Maria Inês Fonseca Cunha
Postoperative respiratory complications
and Obstructive Sleep Apnea Syndrome
Mestrado Integrado em Medicina
Área: Anestesiologia
Trabalho efetuado sob a Orientação de: Doutor Fernando José Pereira Alves Abelha
Trabalho organizado de acordo com as normas da revista: European Journal of Anaesthesiology
and Obstructive Sleep Apnea Syndrome
Aos meus grandes amigos Duarte Leite e Ana Ferro,
Postoperative respiratory complications and Obstructive Sleep Apnea Syndrome.
Maria I Cunha1*
1
. Faculty of Medicine, University of Porto, Portugal. Department of Anesthesiology – Centro Hospitalar São João, Porto, Portugal and Anesthesiology and Perioperative Care Unit – Surgical Department of Faculty of Medicine , University of Porto, Portugal.
* Corresponding author: [email protected] or Faculty of Medicine, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal.
Abstract and Keywords
Context: Obstructive Sleep Apnea Syndrome it has been recognized as a potential
independent risk factor for adverse perioperative outcomes and many of them are undiagnosed.
Objective(s): STOP-BANG score (snore; tired; observed apnea; arterial pressure; body
mass index; age; neck circumference and gender) can predict the risk of a patient to have Obstructive Sleep Apnea. The aim of this study was, to evaluate the incidence of patients with a STOP-BANG ≥3 score and to evaluate its association with postoperative adverse respiratory events.
Design: Observational, prospective study.
Setting: Post-Anesthesia Care Unit of a tertiary hospital: Centro Hospitalar São João,
Porto, Portugal. During the period of 18 June to 12 July 2012.
Patients: 256 patients were admitted and 215 eligible for this study. Written informed
consent was obtained from all patients. Exclusion criteria were patient refusal, incapacity of providing informed consent, a score of <25 in the mini-mental state examination test, age under 18 years, foreign nationality, known neuromuscular disease, urgent/emergent surgery and cardiac surgery, neurosurgery or other procedures that required therapeutic hypothermia.
Main outcome measures: All the patients were asked to complete the STOP
questionnaire and information concerning body mass index, age, neck circumference, and gender (BANG) were collected for every patients.
Results: Incidence of patients with a STOP-BANG ≥3 was 51%. These patients were
older (median age 64 versus 43 years, p<0.001), were more likely to be man (68% versus 48%, p<0.001), had a higher body mass index (median 27.7 versus 25.7, p<0.001), had a higher ASA physical status (ASA III, IV or V 32% versus 15%, p꞊0.004), had higher RCRI scores (8% versus 0% for RCRI>2, p꞊0.002), and showed a higher ischemic heart disease (15% versus 0%, p<0.001), congestive heart disease (5% versus 0%, p꞊0.017), diabetes with insulin therapy (25% versus 7%, p<0.001), hypertension (75% versus 21%, p<0.001), hyperlipidemia (55% versus 13%, p<0.001) and chronic pulmonary obstructive disease (12% versus 3%, p꞊0.011). These patients had more frequently adverse respiratory events (24% versus 10%, p꞊0.011), had a higher incidence of residual neuromuscular blockade (22% versus 15%, p꞊0.021) and longer length of stay in the Hospital (median 7 versus 4 days, p=0.005). In the multiple logistic regression analysis, chronic pulmonary obstructive disease was considered an independent predictor for adverse respiratory events.
Conclusions: Patients with STOP-BANG≥3 score had an important incidence among
patients scheduled to surgery in our hospital, had more co-morbidities and were more prone to postoperative complications.
Introduction
Obstructive Sleep Apnea (OSA) is the most prevalent breathing disorder during sleep (1), it affects 2-26% of the general population (2) and it has been recognized as a potential independent risk factor for an longer length of stay (LOS) in the Hospital and for adverse perioperative outcomes namely respiratory and cardiac complications. (3-5) OSA is characterized by repeated complete occlusion of the upper airway during sleep that last for at least 10 seconds, causing apnoea or hypopnea. (4)
Increasingly OSA has been associated with some diseases such as: obesity, hypertension, dyslipidemia, insulin resistance with development of diabetes, pulmonary arterial hypertension, arrhythmias, atrial fibrillation, stroke (3), deep vein thrombosis (6), gastroesophageal reflux (7) among others.
Some studies show that in the general populations at least 80% of patients with OSA are undiagnosed. (8, 9) The prevalence of OSA in the surgical population is higher than in the general population (3) and 70% of patients undergoing bariatric surgery were found to have OSA. (10)
The gold standard for the diagnosis of OSA, polysomnography (PSG), is impracticable as a routine preoperative assessment tool for OSA because it is an expensive and labour intensive test. (11)
Many tools have been proposed for screening patients for OSA such as the Berlin questionnaire, the STOP questionnaire and the American Society of Anaesthesiologists (ASA) checklist – and the use of these tools improves the likelihood of identifying OSA preoperatively. The STOP questionnaire, showed a high sensitivity for detecting OSA (when score is >3): 93% and 100% for moderate and severe OSA, respectively; however, the specificity at the same cut-off is low: 47% and 37% for moderate and severe OSA, respectively, resulting in high false-positive rates. The STOP questionnaire
is a scoring model consisting of 8 easily administrated questions starting with the acronym STOP-BANG (Appendix) and is scored based on Yes/No answers (scores 1/0). (12)
In a study by Chung F et al (13) the authors compared these three scores, and the STOP questionnaire showed to be the more accurate in identifying the patients who are more likely to develop postoperative complications, like respiratory complications, desaturation and severe desaturation. Conversely, these screening techniques have limited specificity despite a high sensitivity in the diagnosis of OSA.
In the immediate postoperative period the most common causes of hypoventilation include airway obstruction, the effects of anesthetics, analgesics (eg, opioids), sedatives, residual neuromuscular blockade and poorly controlled incisional pain impairing respiration. Impaired oxygen exchange in the postoperative period can occur as a result of intrapulmonary shunting, pulmonary edema and pulmonary embolus.
The most common cause of airway obstruction in the Post Anesthesia Care Unit (PACU) is pharyngeal laxity due to weakness of the pharyngeal muscles. Other causes include laryngospasm, airway edema, hematoma, or a foreign body.
Loss of pharyngeal motor tone leading to muscular laxity is due to residual neuromuscular blockade, residual anesthetic effect, or opioids. Preoperative medical conditions such as obstructive sleep apnea can also predispose to airway obstruction in the PACU. The diaphragm recovers more quickly from the effects of muscle relaxants than the pharyngeal musculature. Residual paralysis of pharyngeal muscles causes the base of the tongue and the tissues of the posterior oropharynx to move toward each other, obstructing the supraglottic inlet. (14, 15)
The aim of this study was, to evaluate the incidence of patients with a STOP-BANG ≥3 score and to evaluate its association with postoperative adverse respiratory events (ARE).
Methods
Subjects and setting
The study was conducted in the in the Post Anesthesia Care Unit (PACU), of Centro Hospitalar São João (CHSJ), Porto, Portugal. Ethical approval (Ethical n.º 127/2012) was provided by the Ethical committee of CHSJ (Comissão de Ética para a Saúde do Hospital de São João – Chairperson Prof Filipe N.A.S. Almeida). Written informed consent was obtained from all patients.
Centro Hospitalar São João is an 1124-bed tertiary hospital in a major metropolitan area that serves 3,000,000 people. This prospective study was conducted in a 12-bed PACU over a 4 week period from Monday through Thursday (from18 June to 12 July 2012). Every patient admitted to the PACU, during this period of time, who was able to provide written informed consent was included in the study. Exclusion criteria were patient refusal, incapacity of providing informed consent, a score of <25 in the mini-mental state examination test (MMSE), age under 18 years, foreign nationality, known neuromuscular disease, urgent/emergent surgery and cardiac surgery, neurosurgery or other procedures that required therapeutic hypothermia.
All the patients were asked to complete the STOP questionnaire. Information concerning body mass index (BMI) age, neck circumference, and gender (BANG) were collected by a research assistant.
Patients were classified as being at high risk for obstructive sleep apnea (HR-OSA) if their STOP-BANG score was 3 or greater and as being at low risk of OSA (LR-OSA) if their score was less than 3.
The anesthesiologist in charge was blinded to patient involvement in the study. Anesthesia was provided and monitored according to the criteria of the anesthesiologist in charge criteria, but this conduct followed minimum departmental standards.
Neuromuscular blocking drugs (NMBD) were used for tracheal intubation, and additional boluses were provided, if needed. No written policy exists concerning the use of neuromuscular monitoring so this was performed at the discretion of the anesthesiologist. To ensure that the anesthesiologist remained blinded to the patients’ participation in the study, we did not attempt to observe the use or interpretation of TOF intraoperatively. The anesthesiologist was free to decide whether to reverse the neuromuscular blockade (NMB) with neostigmine at the conclusion of the surgical procedure.
Usually, the patient was extubated in the operating room and transferred to the PACU. Criteria for extubation included sustained head lift or hand grip for more than 5 s, the ability to follow simple commands, a stable ventilatory pattern with an acceptable arterial oxygen saturation (SpO2) >95%, and a TOF ratio of greater than 0.80. All subjects were administered 100% oxygen by a facemask after tracheal extubation. The anesthesiologist was free to decide whether to administer oxygen during the time between transfer to the cart and admission to the PACU.
Upon arrival to the PACU oxygen was provided to all subjects by either a nasal cannula or face mask.
A standardized data collection sheet was completed for each patient.
The recorded patients characteristics were: age, gender, weight, height, BMI, benzodiazepines administration before surgery, chronic benzodiazepines use, site of surgery (intra-abdominal, musculoskeletal, head and neck), American Society of Anesthesiologists physical status (ASA-PS), Revised Cardiac Risk Index (RCRI), duration of preoperative fluid fasting, type of anesthesia, duration of surgery, use of nitrous oxide, ARE in the PACU, postoperative pain level (VAS score), postoperative
nausea and vomiting 6 hours after surgery and 24 hours after surgery, LOS in the PACU and in the Hospital.
The magnitude of the surgical procedure was classified as major (surgery in which body cavities or major vessels are exposed to ambient temperature such as major abdominal, thoracic, or major vascular, thoracic spine surgery with instrumentation, or hip arthroplasty), medium (surgery in which body cavities are exposed to a lesser degree such as appendectomy), and minor surgery (superficial surgery). Major surgery was defined as a surgery requiring a hospital stay of 2 or more days.
Clinical risk factors (history of chronic obstructive lung disease, history of ischemic heart disease, history of compensated or prior heart failure, history of cerebrovascular disease, diabetes mellitus and renal insufficiency) and surgical risk (high-risk defined as intrathoracic, intraperitoneal, or suprainguinal vascular surgery, or surgery involving large blood loss or fluid shifts) were defined according to the Cardiac Risk Stratification for Noncardiac Surgical Procedures of the 2007 guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. (16)
Data for other preoperative clinical information regarding chronic obstructive pulmonary disease (COPD), hypertension and dyslipidemia were collected from routine clinical documentation entered into the institution’s perioperative clinical information system.
Residual neuromuscular block (RNMB) was defined as TOF<0.9 and it was quantified at admission to the PACU using acceleromyography of the adductor pollicis muscle (TOF-Watch®). (17, 18)
For delirium screening, at PACU discharge and in the ward the next day after surgery, the nursing delirium screening scale were (Nu-DESC) (19) used, and patients with a Nu-DESC score of 2 or more points at least at one evaluation were considered delirium positive. Patients were tested for delirium by the research team at the time they were formally declared to be ‘ready for discharge’ to the regular ward by the physician in charge of the recovery room. In addition, the patients were seen on the morning of the first postoperative day.
Postoperative respiratory complications
Each postoperative ARE was defined on the data collection sheet using the following criteria according to the classification described by Murphy et al (20): upper airway obstruction requiring an intervention (jaw thrust, or oral or nasal airway); mild-moderate hypoxia (Spo2 of 93%–90%) on 3 L nasal cannula O2 that was not improved after active interventions (increasing O2 flows to > 3 L/min, application of high-flow face mask O2, verbal requests to breathe deeply and tactile stimulation); severe hypoxia (Spo2 <90%) on 3 L nasal cannula O2 that was not improved after active interventions (increasing O2 flows to >3 L/min, application of high-flow facemask O2, verbal requests to breathe deeply, and tactile stimulation); signs of respiratory distress or impending ventilatory failure (respiratory rate >20 breaths per minute, accessory muscle use, and tracheal tug); Inability to breathe deeply when requested to by the PACU nurse; patient complaining of symptoms of respiratory or upper airway muscle
weakness (difficulty breathing, swallowing, or speaking); patient requiring reintubation in the PACU and Clinical evidence or suspicion of pulmonary aspiration after tracheal extubation (gastric contents observed in the oropharynx and hypoxemia).
During the PACU stay the patients were observed continuously by the PACU nurses who contacted a study investigator without delay if a ARE was observed. The inability to breathe deeply and the assessement of symptoms of respiratory or upper airway muscle weakness were observed in intervals of 10 minutes. One other investigators of study then examined the patient to confirm that the patient met at least one of the criteria for an ARE.
Statistical method
Descriptive analysis of variables was used to summarize data. Ordinal and continuous data found not to follow a normal distribution, based on the Kolmogorov–Smirnov test for normality of the underlying population, are presented as median and interquartile range. Normally distributed data are presented as mean and standard deviation (SD). An univariate analysis was performed to identify differences between HR-OSA and LR-OSA patients, using the Mann-Whitney U test to compare continuous variables and Chi-square or Fisher’s exact test to compare proportions between 2 groups of subjects. Differences were considered statistically significant when P was <0.05.
A univariate analysis was performed to identify predictors for ARE. Multiple regression binary logistic was used with forward conditional method in the model in order to identify independent predictors for ARE. In this model, all covariates with p<0.05 in the univariate analyses were entered and an odds ratio (OR) and 95% Confidence Interval
Data was analyzed using SPSS software for Windows Version 19.0 (SPSS Inc., Chicago, IL, USA).
Results
Form 256 patients consecutively admitted in the PACU during the study period, a total of 215 were studied.
Forty-one patients were excluded: 12 patients were admitted to a surgical intensive care unit, 8 patients were unable to provide informed consent or had a MMSE <25, 2 patients did not undergo surgery, 2 patient underwent neurosurgery, 11 patient were less than 18 years old, 3 patient did not speak Portuguese and 3 patient refused to participate.
Of 215 patients include in the analysis (Table 1), 110 were classified as HR-OSA. These patients were older (median age 64 versus 43 years, p<0.001), had a higher BMI (median 27.7 versus 25.7, p<0.001), were more likely to be man (68% versus 48%, p<0.001), had a higher ASA physical status (ASA III, IV or V 32% versus 15%, p꞊0.004), and had higher RCRI scores (8% versus 0% for RCRI>2, p꞊0.002).
Patients with HR-OSA showed a higher prevalence of pre-existing co-morbidities, including ischemic heart disease (15% versus 0%, p<0.001), congestive heart disease (5% versus 0%, p꞊0.017), diabetes with insulin therapy (25% versus 7%, p<0.001), hypertension (75% versus 21%, p<0.001), hyperlipidemia (55% versus 13%, p<0.001) and COPD (12% versus 3%, p꞊0.011).
HR-OSA patient were submitted more frequently to intra-abdominal surgery (59% versus 37%, p꞊0.005) and less frequently to musculoskeletal (34% versus 49%, p꞊0.004) or head and neck surgery (7% versus 14%, p꞊0.002). HR-OSA patients were underwent more frequently loco regional anesthesia (23% versus 11%, p꞊0.049) and less frequently to general or combined anesthesia (77% versus 89%, p꞊0.049) and had hypothermia more frequently at PACU admission (36% versus 24%, p=0.045). HR-OSA patients had a longer LOS in the Hospital (median 7 versus 4 days, p꞊0.005).
Regarding respiratory complications (Table 2) that occurred in the PACU, patients with HR-OSA had more frequently ARE (24% versus 10%, p꞊0.011). HR-OSA patients had more frequently mild/moderated hypoxia (16% versus 6%, p꞊0.013) and a decreased inspiratory capacity (18% versus 5%, p꞊0.002).
In a multivariate analyses occurrence (Table 3) and after adjustment for univariate predictor (age, hypertension, COPD and HR-OSA), only COPD was identified as an independent predictor of ARE.
Discussion
In this study the incidence of patients with a STOP-BANG ≥3 were 51% what is a considerable and relevant figure for an incidence among patients undergoing elective surgery in our hospital.
We relied on a STOP-BANG ≥3, since this has been demonstrated to have a very high sensitivity to screen patients with moderate/severe OSA. (12) Indeed recent systemic review by Abrishami et al. (21) showed that STOP-BANG questionnaire have a higher methodological quality and as Chung F et al. (12) suggest this cut-off may be adequate to stratify patients with unrecognized OSA in the surgical population at higher risk of postoperative complications. This author stated that this questionnaire is concise and simple to use and may help on the identification of HR-OSA patients.
HR-OSA patients were more frequently males and as expected had a higher BMI (p<0.001) and were older (p<0.001). Similar results have been found by others (22, 23) and its importance is revealed by the inclusion of these variables in different tools used to access for OSA severity like sleep apnea clinical score (SACS) and even STOP-BANG.
The association between increased morbidity and untreated OSA is well established, which may result in an increased mortality rate (3, 24) and these patients are at an increased risk of developing cardiovascular disease. (25) In our study, we also realize that HR-OSA group had more frequently history of cardiac co-morbidities (ischemic heart disease and congestive heart disease), higher frequency of hypertension (22, 26-28), hyperlipidaemia, diabetes (29) and also pulmonary chronic disease. This co-morbidities may had although indirectly reflect a higher ASA physical status and higher RCRI scores in the HR-OSA patients.
Patients with HR-OSA were more frequently submitted to abdominal surgery, and loco regional anesthesia and had more frequently hypothermia. We may suppose that these three circumstances may be linked and may had influenced the simultaneous occurrence of each other.
As well as was described in retrospective studies (5, 30, 31) our study revealed that HR-OSA patients had also a longer LOS in the Hospital. Liu S et al (31) suggests that postoperative hypoxemia may occur not only in the first postoperative day and it was associated with adverse outcomes as frequent respiratory interventions, more need for intensive monitoring and a longer LOS in the Hospital. In the other hand Rakesh G et al (5) suggest that a longer LOS in the Hospital was associated with coronary artery disease and metabolic syndrome.
Patients with a STOP-BANG score ≥3 had also a higher incidence of RNMB. It is described that patients with a high BMI had a higher incidence of RNMB. (32) This fact has not yet been described for the patients with OSA, but our results suggest that enhanced monitoring is important in HR-OSA patients because they are exposed to additional risk for respiratory complications and the prevalence of patients with high BMI is higher in the HR-OSA patients.
The incidence of postoperative respiratory complications was higher in patients who have STOP-BANG score ≥3. This is in agreement with other studies (5, 33) that found respiratory events to occur more frequently, particularly postoperative hypoxia that had a higher incidence in the patients at HR-OSA. However, in our study, as in the study of Chung et al (34) analysis of perioperative adverse events did not show significant respiratory morbidity in HR-OSA patients compared to the LR-OSA patients. In fact in our study we could not found that HR-OSA was a determinant for ARE.
This study has several limitations. The first and more important limitation is that it was not possible to compare the results of the STOP-BANG questionnaire with a definitive polysomnographic diagnosis. Second, our patients may have been at high risk for postoperative events without having OSA. The use of the STOP-BANG score is used as an instrument to predict the risk of a patient to have OSA may have led to a high incidence of false positive results. It is possible that a higher score should have been used because recent studies had showed that the STOP-BANG score has a higher accuracy of detecting moderate to severe OSA patients in a surgical population when the score is greater than or equal to 5. (12) Third, the respiratory events were only registered in the PACU and complications that could have occurred after PACU discharge were not considered. This might be viewed as a major limitation since respiratory complications after surgery may be associated with adverse outcomes that occur during the hospital stay after PACU discharge.
In conclusion the principal findings in our study were:
The incidence of HR-OSA patients was 51%;
HR-OSA patients had more co-morbidities as ischemic heart disease, congestive
heart disease, use of insulin to treated diabetes, hypertension, hyperlipidemia and COPD;
HR-OSA patients have a higher incidence of postoperative respiratory
complications, including mild/moderate hypoxia and decreased inspiratory capacity.
HR-OSA patients demonstrated a longer LOS in the Hospital.
Acknowledgements
The author would like to thank all the Post-Anesthesia Care Unit staff for the assistance with the study.
There was no financial support or sponsorship.
References
1. Kryger H. Diagnosis and management of sleep apnea syndrome. Clinical
cornerstone 2000; 2(5): 39-47.
2. Young T, Hutton R, Finn L et al. The gender bias in sleep apnea diagnosis. Are women missed because they have different symptoms? Archives of internal medicine 1996; 156(21): 2445-51.
3. Chung A, Yuan H, Chung F. A systemic review of obstructive sleep apnea and its implications for anesthesiologists. Anesth Analg 2008; 107(5): 1543-63.
4. Porhomayon J, El-Solh A, Chhangani S et al. The management of surgical patients with obstructive sleep apnea. Lung 2011; 189(5): 359-67.
5. Gupta M, Parvizi J, Hanssen D et al. Postoperative complications in patients with obstructive sleep apnea syndrome undergoing hip or knee replacement: a case-control study. Mayo Clin Proc 2001; 76(9): 897-905.
6. Ambrosetti M, Lucioni A, Ageno W et al. Is venous thromboembolism more frequent in patients with obstructive sleep apnea syndrome? Journal of thrombosis and
haemostasis : JTH 2004; 2(10): 1858-60.
7. Gislason T, Janson C, Vermeire P et al. Respiratory symptoms and nocturnal gastroesophageal reflux: a population-based study of young adults in three European countries. Chest 2002; 121(1): 158-63.
8. Kapur V, Strohl P, Redline S et al. Underdiagnosis of sleep apnea syndrome in U.S. communities. Sleep & breathing = Schlaf & Atmung 2002; 6(2): 49-54.
9. Young T, Evans L, Finn L et al. Estimation of the clinically diagnosed proportion of sleep apnea syndrome in middle-aged men and women. Sleep 1997; 20(9) :705-6.
10. Frey C, Pilcher J. Obstructive sleep-related breathing disorders in patients evaluated for bariatric surgery. Obes Surg 2003; 13(5): 676-83.
11. Stierer L, Wright C, George A et al. Risk assessment of obstructive sleep apnea in a population of patients undergoing ambulatory surgery. J Clin Sleep Med 2010; 6(5): 467-72.
12. Chung F, Subramanyam R, Liao P et al. High STOP-Bang score indicates a high probability of obstructive sleep apnoea. Br J Anaesth 2012; 108(5): 768-75.
13. Chung F, Yegneswaran B, Liao P et al. Validation of the Berlin questionnaire and American Society of Anesthesiologists checklist as screening tools for obstructive sleep apnea in surgical patients. Anesthesiology 2008; 108(5): 822-30.
14. Shorten D, Opie J, Graziotti P et al. Assessment of upper airway anatomy in awake, sedated and anaesthetised patients using magnetic resonance imaging. Anaesth
Intensive Care 1994; 22(2): 165-9.
15. Mathru M, Esch O, Lang J et al. Magnetic resonance imaging of the upper airway. Effects of propofol anesthesia and nasal continuous positive airway pressure in humans. Anesthesiology 1996; 84(2): 273-9.
16. Fleisher A, Beckman A, Brown A et al. ACC/AHA 2007 Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 2002 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery) Developed in Collaboration With the American Society of Echocardiography, American Society of Nuclear Cardiology, Heart Rhythm Society, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society
for Vascular Medicine and Biology, and Society for Vascular Surgery. J Am Coll
Cardiol 2007; 50(17): 1707-32.
17. Murphy S, Brull J. Residual neuromuscular block: lessons unlearned. Part I: definitions, incidence, and adverse physiologic effects of residual neuromuscular block.
Anesth Analg 2010; 111(1): 120-8.
18. Murphy S. Residual neuromuscular blockade: incidence, assessment, and relevance in the postoperative period. Minerva Anestesiol 2006; 72(3): 97-109.
19. Gaudreau D, Gagnon P, Harel F et al. Fast, systematic, and continuous delirium assessment in hospitalized patients: the nursing delirium screening scale. J Pain
Symptom Manage 2005; 29(4): 368-75.
20. Murphy S, Szokol W, Marymont H et al. Intraoperative acceleromyographic monitoring reduces the risk of residual neuromuscular blockade and adverse respiratory events in the postanesthesia care unit. Anesthesiology 2008; 109(3): 389-98.
21. Abrishami A, Khajehdehi A, Chung F. A systematic review of screening questionnaires for obstructive sleep apnea. Canadian journal of anaesthesia = Journal
canadien d'anesthesie 2010; 57(5): 423-38.
22. Ramachandran K, Kheterpal S, Consens F et al. Derivation and validation of a simple perioperative sleep apnea prediction score. Anesth Analg 2010; 110(4): 1007-15. 23. Tishler V, Larkin K, Schluchter D et al. Incidence of sleep-disordered breathing in an urban adult population: the relative importance of risk factors in the development of sleep-disordered breathing. JAMA 2003; 289(17): 2230-7.
24. Hung J, Whitford G, Parsons W et al. Association of sleep apnoea with myocardial infarction in men. Lancet 1990; 336(8710): 261-4.
25. Gottlieb J, Yenokyan G, Newman B et al. Prospective study of obstructive sleep apnea and incident coronary heart disease and heart failure: the sleep heart health study.
Circulation 2010; 122(4): 352-60.
26. Peppard E, Young T, Palta M et al. Prospective study of the association between sleep-disordered breathing and hypertension. The New England journal of medicine 2000; 342(19): 1378-84.
27. Nieto J, Young B, Lind K et al. Association of sleep-disordered breathing, sleep apnea, and hypertension in a large community-based study. Sleep Heart Health Study.
JAMA 2000; 283(14): 1829-36.
28. Ohayon M, Guilleminault C, Priest G et al. Is sleep-disordered breathing an independent risk factor for hypertension in the general population (13,057 subjects)? J
Psychosom Res 2000; 48(6): 593-601.
29. Coughlin R, Mawdsley L, Mugarza A et al. Obstructive sleep apnoea is independently associated with an increased prevalence of metabolic syndrome. Eur
Heart J 2004; 25(9): 735-41.
30. Ballantyne H, Svahn J, Capella F et al. Predictors of prolonged hospital stay following open and laparoscopic gastric bypass for morbid obesity: body mass index, length of surgery, sleep apnea, asthma, and the metabolic syndrome. Obes Surg 2004; 14(8): 1042-50.
31. Liu S, Chisholm F, Ngeow J et al. Postoperative hypoxemia in orthopedic patients with obstructive sleep apnea. HSS journal : the musculoskeletal journal of
Hospital for Special Surgery 2011; 7(1): 2-8.
32. Gaszynski T, Szewczyk T, Gaszynski W. Randomized comparison of sugammadex and neostigmine for reversal of rocuronium-induced muscle relaxation in morbidly obese undergoing general anaesthesia. Br J Anaesth 2012; 108(2): 236-9.
33. Liao P, Yegneswaran B, Vairavanathan S et al. Postoperative complications in patients with obstructive sleep apnea: a retrospective matched cohort study. Canadian
journal of anaesthesia = Journal canadien d'anesthesie 2009; 56(11): 819-28.
34. Chung F, Ward B, Ho J et al. Preoperative identification of sleep apnea risk in elective surgical patients, using the Berlin questionnaire. J Clin Anesth 2007; 19(2): 130-4.
Appendix: STOP-BANG Scoring Model
1. Snoring. Do you snore loudly (louder than talking ou loud enough to be heard)?
Yes No
2. Tired. Do you often feel tired, fatigued, or sleepy during daytime?
Yes No
3. Observed. Has anyone observed you stop breathing during your sleep?
Yes No
4. Blood pressure. Do you have or are you being treated for high blood pressure?
Yes No
5. Body Mass Index. Body Mass Index more than 35 kg/m2?
Yes No
6. Age. Age over 50 years old?
Yes No
7. Neck circumference. Neck circumference greater than 40 cm?
Yes No
8. Gender. Gender male?
Yes No
High risk of Obstructive Sleep Apnea: answering yes to three or more items.
Table 1. Patient baseline characteristics (n= 215) Variable All N=215 HR-OSA N=110 LR-OSA N=105 p
Age, median (IQR) 58 (43-68) 64 (58 – 72) 43 (33 – 57) <0.001(c)
Gender, n (%) <0.001(a) Male 125 (58) 75(68) 50 (48) Female 90 (42) 35(32) 55 (55) Site of Surgery, n (%) Intraabdominal 104 (48) 65 (59) 39 (37) 0.005(a) Musculoskeletal 88 (41) 37 (34) 51 (49) 0.004(a)
Head and Neck 23 (11) 8 (7) 15 (14) 0.002(a)
Body Mass Index (Kg/m2) 26.2 (23.6-30.0) 27.7 (24.4-32.1) 25.7(22.2 -28.1) <0.001(c)
ASA physical status, n (%) 0.004(a)
I/II 164 (76) 75 (68) 89 (85)
III/IV/V 51 (24) 35 (32) 16 (15)
High Risk surgery, n (%) 61 (28) 42 (38) 19 (18) 0.001(a) Ischemic heart disease, n (%) 17 (8) 17(15) 0 <0.001(b) Congestive heart disease, n (%) 6(3) 6 (5) 0 0.017(b) Cerebrovascular disease, n (%) 3(1) 3 (3) 0 0.132(b) Insulin therapy for diabetes, n (%) 35 (16) 28(25) 7(7) <0.001(a) Renal insufficiency, n, (%) 15 (7) 9 (8) 6(6) 0.478(a)
RCRI, n (%) 0.002(b) RCRI≤2 206 (96) 101(92) 105 (100) RCRI>2 9 (4) 9 (8) 0 Hypertension, n (%) 104 (48) 82 (75) 22(21) <0.001(a) Hyperlipidemia, n (%) 74 (34) 60 (55) 14 (13) <0.001(a) COPD, n (%) 16 (7) 13 (12) 3 (3) 0.011(b)
Type of anesthesia, n (%) 0.049(a)
Loco regional 36 (17) 25 (23) 11 (11)
General / combined 179 (83) 85(77) 94(89)
Magnitude of surgery, n (%) 0.170(a)
Minor 18 (8) 11 (10) 7 (7)
Medium 111(52) 50 (46) 61 (58)
Major 86 (40) 49(45) 37 (35)
Bariatric surgery, n (%) 8 (4) 6 (5) 2 (2) 0.156(b) Duration surgery, median (IQR) 90 (55 – 145) 90 (54-141) 90 (54-148) 0.849(c) Post-operative delirium hospital, n (%) 22 (10) 15 (14) 7 (7) 0.092(a) Temperature on admission, median (IQR) 35.5(34.9-36.0) 35.5(34.9-36.0) 35.5(35.1-36.0) 0.358(c)
<35ºC, n (%) 65 (30) 40 (36) 25 (24) 0.045(a)
Length of PACU stay (minutes), median (IQR) 112 (80-150) 118 (85-160) 105 (80-148) 0.081(c) Length of Hospital stay (days) 6 (3-12) 7 (5-17) 4 (2-8) 0.005(c) Perioperative muscle relaxant use, n (%) 132 (61) 61 (55) 71(65) 0.156(a) Neuromuscular residual blocking, n (%) 40 (30) 24 (22) 16(15) 0.021(a)
a) Pearson's chi-squared test b) Fisher’s exact test c) Mann-Whitney U test IQR, Interquartil range
HR-OSA, High-risk of OSA; ASA, American Society of Anesthesiologists; RCRI, Revised cardiac risk index; COPD, Chronic Pulmonary Obstructive Disease; PACU, Post Anesthesia Care Unit
Table 2. Respiratory complications (n= 215) Variable All (n=215) HR-OSA (n=110) LR-OSA (n=105) p Respiratory events 37 26 (24) 11 (10) 0.011 Obstruction airway 3 1 (1) 2 (2) 0.534 Hypoxia (mild/moderate) 24 18 (16) 6 (6) 0.013 Hypoxia Severe 4 2 (2) 2 (2) 0.672 Respiratory failure 4 2 (2) 2 (2) 0.672
Inspiratory capacity decreased 25 20 (18) 5 (5) 0.002
Muscle weakness 9 7 (6) 2 (2) 0.103
Table 3. Multivariate regression analysis for predictors of adverse respiratory events
Variable Simple OR (95%CI) p *OR (95% CI) Pa
Age 1.0 (1.0 – 1.1) 0.046 -
Hypertension 2.6 (1.2 – 5.5) 0.012 -
COPD 4.4 (1.5– 12.7) 0.006 4.4 (1.5– 12.7) 0.006
HR-OSA 2.7 (1.2 – 5.7) 0.013 - -
a) Logistic regression analysis with forward conditional elimination method was used with an entry criterion of p < 0.05.
OR; Odds Ratio; CI, Confidence Interval
COPD, Chronic Obstructive Pulmonary Disease; HR-OSA, High-Risk of Obstructive Sleep Apnea
*Adjusted OR for age, hypertension, COPD and HR-OSA (variables considered to be determinants for adverse respiratory events in a univariate analyses).
Guidance for Authors on the Preparation and Submission of Manuscripts to the
European Journal of Anaesthesiology
Note: These instructions comply with those formulated by the International Committee
of Medical Journal Editors (ICMJE). For further details, authors should consult the
following article: International Committee of Medical Journal Editors. “Uniform
Requirements for Manuscripts Submitted to Biomedical Journals” New Engl J Med
1997, 336:309–315. The complete document appears at http://www.icmje.org.
Scope
The European Journal of Anaesthesiology (EJA) publishes original work of high
scientific quality in the field of anaesthesiology, pain, emergency medicine and
intensive care. Preference is given to experimental work or clinical observation in man,
and to laboratory work of clinical relevance. The journal also publishes commissioned
reviews by an authority, abstracts of scientific meetings, editorials, commentaries,
We ask you to confirm that your paper has not been published in its current form or a
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material that you have posted on a web site), we ask you to proceed with your
submission but to include a copy of the relevant previously published work or work
under consideration by other journals. Authors must draw attention to any published
work that concerns the same patients or subjects as the present paper in a covering letter
with their article.
Conflicts of interest
Authors must state all possible conflicts of interest in the manuscript, including
financial, consultant, institutional and other relationships that might lead to bias or a
paragraph: Acknowledgements).
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The EJA requires you to send us copies of permission to reproduce material (such as
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please obtain it or remove the identifying material.
A statement to the effect that such consent had been obtained must be included in the
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All articles dealing with original human or animal data must include a statement on
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The paragraph could read, for example:
Ethics: Ethical approval for this study (Ethical Committee N° NAC 207) was provided
by the Ethical Committee NAC of Geneva University Hospitals, Geneva, Switzerland
(Chairperson Prof N. Dupont) on 12 February 2007.
In addition and as stated above, for studies conducted on human participants you must
state clearly that you obtained written informed consent from the study participants;
please also look at the latest version of the Declaration of Helsinki. Similarly, for
experiments involving animals you must state the care of animal and licensing
guidelines under which the study was performed and report these in accordance with the
requests, please state why it was not required. Please note that the editors may ask you
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Agency (or similar) please state this and provide details, this can be particularly useful
when discussing the use of unlicensed drugs.
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The European Journal of Anaesthesiology adheres to the guidelines on adequate data
reporting that were established by The Enhancing the QUAlity and Transparency Of
health Research (EQUATOR) network (http://www.equator-network.org/home/). For
more information, see the EJA Editorial: Guidelines on adequate data reporting: use
them!
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validity of the results reported.
All persons designated as authors should qualify for authorship and all those who
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Acquisition of funding, the collection of data or general supervision of the research
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who are not authors should be named in the Acknowledgements section.
Retractions
as on Overlapping Publications.
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All manuscripts and materials must be submitted through the web-based tracking
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system. Authors should NOT in addition then post a hard copy submission to the
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article, plus an electronic version on disk or CD-ROM to the following address:
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Wilkins, 250 Waterloo Road, London, SE1 8RD, UK.
1.5 spacing should be used throughout the manuscript, which should include the
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the Title Page, and the page number should be placed in the top right hand corner of
each page. Two letter abbreviations should be avoided. Longer abbreviations should be
defined on their first appearance in the text; those not accepted by international bodies
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Article Types
Randomised Controlled Trials
Authors are requested to report these in accordance with the CONSORT (Consolidated
the study was performed and to judge whether the findings are likely to be reliable (see
EJA Editorial: Adherence to guidelines for improved quality of data reporting: where
are we today?). Please provide the following:
• A flow chart showing the progress of participants through the study. The example
flowchart may be adapted as required.
• A checklist for editors and reviewers (not for publication) showing that you have
described the recommended respective key points in your report.
Maximum length of reports of randomised controlled trials is 3500 words. Please
provide a structured abstract (max. 400 words, see subheading Structured Abstract).
Observational Study (Cohort, Case-control, Cross-sectional, Case Series)
Authors are requested to report these in accordance with the STROBE (STrengthening
the Reporting of OBservational studies in Epidemiology) statement [
www.strobe-statement.org].
Maximum length of reports of observational studies is 3500 words. Please provide a
Studies of Diagnostic Accuracy
Authors are requested to report these in accordance with STARD (STandard for the
Reporting of Diagnostic accuracy) statement [www.stard-statement.org].
Maximum length of reports of Diagnostic studies is 3500 words. Please provide a
structured abstract (max. 400 words, see subheading Structured Abstract).
Systematic Reviews (with or without meta-analysis)
Authors are requested to submit these as ‘Original articles’ (not ‘Reviews’) and report
them in accordance with the PRISMA (Transparent Reporting of Systematic Reviews
and Meta-Analyses) Statement [www.prisma-statement.org]. This ensures that enough
information is provided for editors, peer reviewers, and readers to see how the study
was performed and to judge whether the findings are likely to be reliable (see EJA
Editorial: Adherence to guidelines for improved quality of data reporting: where are we
today?). Please provide the following:
described the recommended respective key points in your report.
Maximum length of reports of systematic reviews is 3500 words. Please provide a
structured abstract (max. 400 Words, see subheading Structured Abstract). Authors are
encouraged to publish additional material (for instance, large tables, figures with forest
plots, data from subgroup analyses etc.) as Supplemental Digital Content (see above for
details).
Conventional, Non-systematic Reviews
These are usually commissioned. Maximum length of reviews is 3500 words. Please
provide an unstructured abstract (max. 250 words). Please include a title page giving the
author's name, address, email address, phone and fax numbers, as well as an
Acknowledgement statement (see paragraph: Acknowledgements) and signed copyright
forms.
Practice Parameters, Recommendations, Consensus Statements, Position Papers) should
describe:
1. The clinical problem to be addressed;
2. The mechanism by which the statement was generated;
3. A review of the evidence for the statement (if available), and;
4. The statement on practice itself.
As more than one group or society may issue statements on the same topic, this often
results in confusion amongst clinicians. To minimize confusion and to enhance
transparency, such statements should begin with the following bulleted phrases,
followed by brief comments addressing each phrase:
What other guideline statements are available on this topic?
Why was this guideline developed?
How does this statement differ from existing guidelines?
Why does this statement differ from existing guidelines?
usually commissioned. Editorials should be up to 1500 words long with no more than
15 references. Please include a title page giving all authors' names, addresses, email
addresses, phone and fax numbers, as well as an Acknowledgement statement (see
paragraph: Acknowledgements) and signed copyright forms. Editorials do not have an
abstract.
Commentaries
Commentaries discuss issues that are directly related to published material.
Commentaries accompany original articles, critically appraise their results and put their
conclusions into a wider context. Commentaries are always commissioned and should
be up to 1000 words long with no more than 10 references. Commentaries do not have
an abstract. Please include a title page giving the author's name, address, email address,
phone and fax numbers, as well as an Acknowledgement statement (see paragraph:
In this section, we publish case reports, letters and replies. Items in the Correspondence
section are peer reviewed. Please look at a very recent copy of the European Journal of
Anaesthesiology to see how the material should be presented. The format (layout) for
the Correspondence section is quite different from our other articles. The absolute
maximum is 1000 words, which must include the space for any tables and illustrations
(this is approximately two sides of printed matter in the Journal). References are limited
to seven.
Correspondence articles do not have an abstract. Please include a title page giving the
author's name, address, email address, phone and fax numbers, as well as an
Acknowledgement statement (see paragraph: Acknowledgements) and signed copyright
forms.
Case Reports
Case reports should follow the guidance for correspondence (see above). In addition
case reports dealing with patients must state that informed consent to publication was
Title Page
The Title Page should carry the full title of the paper and a short title to be used as a
‘running head’ (and which should be so identified). Please, include the study design in
the title; for instance, “randomized trial”, or “systematic review”. Titles should be as
informative and complete as possible. The EJA Editorial: How to write a good title
provides some help. The first name, middle initial and last name of each author and
their affiliations should appear. Academic degrees should not be stated. If the work is to
be attributed to a department or institution, its full name should be included. The name
and address of the corresponding author and the name and address of the author to
whom requests for reprints should be made should also appear on the Title Page.
Structured Abstract
For original articles, the second page should carry an abstract, which will be printed at
the beginning of the paper and should not be more than 400 words. Use the following
headings and information as appropriate (which are adapted from the BMJ and JAMA
and it should not contain abbreviations or references (see EJA Editorial: Writing the
abstract: completeness and accuracy matter).
Example: Randomised controlled trial, observational study, diagnostic study,
animal study
Context: Explaining the clinical (or other) importance of the study question.
Objective(s): Including a clear statement of the main aim(s) of the study and the major
hypothesis tested or research question posed. Avoid statements such as “We aimed to
evaluate the effectiveness of X”.
Design: For example, randomised-controlled study, case control study, crossover study,
observational study, survey, diagnostic test etc.
Setting: Include the level of care e.g. primary, secondary; number of participating
centres. Be general rather than give the name of the specific centre, but give the
geographical location if this is important. Include the dates of the study period.
Patients, other participants (delete what does not apply): Numbers entering and
included in the Design or Setting section.
Intervention(s): What, how, when and for how long. This heading can be deleted if
there were no interventions but should normally be included for randomised controlled
trials, cross over trials, and before and after studies.
Main outcome measures: What was the primary endpoint? What outcome measures
were planned in protocol, which were finally measured (if different, explain why)?
Results: Main results with (for quantitative studies) 95% confidence intervals and,
where appropriate, the exact level of statistical significance.
Conclusions: Primary conclusions and their implications, suggest areas for further
research if appropriate.
Trial registration: If appropriate, the trial registration should be stated at the end of the
abstract, for example: “Trial registration: Clinicaltrials.gov identifier: NCT00405977.”
Example: Systematic reviews with or without meta-analyses
Context:
analyses.
Data sources: Where included studies were retrieved from? Include years searched.
Eligibility criteria: Describe inclusion and non-inclusion criteria of selected studies.
Results:
Conclusions:
Key Words
The abstract should be followed by a list of 3–10 key words or short phrases which will
assist the cross-indexing of the article. When possible, the terms used should be from
the Medical Subject Headings list of the National Library of Medicine.
Text
The remainder of the text should be divided into sections headed Introduction, Methods
(including ethical and statistical information), Results, and Discussion (including a
The acknowledgements section should contain three distinct statements in three separate
paragraphs:
1. Assistance with the article. Acknowledgements should be made only to those who
have made a substantial contribution to the study. Authors are responsible for obtaining
written permission from people acknowledged by name in case readers infer their
endorsement of data and conclusions. If there was no assistance state: none declared.
2. Financial support and sponsorship. You must make reference to all relevant sources
of funding concerning this article. If there were no sources of funding please state: none
declared.
3. Conflicts of interest. You must make reference to all relevant conflicts of interest
concerning this article. If there are no conflicts of interest please state: none declared.
For example:
Acknowledgements
Assistance with the study: We would like to thank Dr John A. Smith for his assistance
Anaesthesiology, London Hospital, London, UK.
Conflicts of interest: A has received honoraria from Company Z. B is currently
receiving a grant (#12345) from Organisation Y, and C is on the speaker’s bureau for
Organisation X. For the remaining authors none were declared.
References
Number references consecutively in the order in which they are first mentioned in the
text. Identify references in the text, tables and legends using superscripted Arabic
numerals that are placed after the punctuation. References cited only in tables or in
legends to figures should be numbered in accordance with the sequence established by
the first identification in the text of the particular table or illustration.
Use the Vancouver reference system as adopted by the U.S. National Library of
Medicine ensuring that all journal titles conform to Index Medicus approved
abbreviations. If in doubt, look up the reference list of a recent paper published in the
Unpublished observations and personal communications should not be used as
references, although references to written (not verbal) communications may be inserted
(in parentheses) in the text. Manuscripts that have been accepted but not yet published
(e.g. Epub ahead of print) should be included in the list, followed by (in press).
Information from manuscripts not yet accepted may be cited only in the text as
(unpublished observations). Authors should verify references against the original
documents before submitting the article.
Electronic or online references should be cited in the reference list only if the material
referenced is a specific article (e.g. a paper published in a web-based journal); see below
for correct style. Less specific references (e.g. the web pages of societies, organisations
and university departments) should not appear in the references; instead the URL should
be cited in full in the text.
Authors must confirm that the details of these references are accurate and complete. In
the full list of references give the names and initials of all authors. If there are more than
six, cite only the first three names followed by et al. The authors' names are followed by
last page numbers in full followed by a full stop. Titles of books should be followed by
the town and country of publication, the publisher, the year and inclusive page numbers.
See the following examples:
Journal articles
Pollard BJ, Bryan A, Bennett D et al. Recovery after oral surgery with halothane,
enflurane, isoflurane or propofol anaesthesia. Br J Anaesth 1994; 72: 559–566.
Books
Korttila K. Recovery period and discharge. In: White P, ed. Outpatient Anaesthesia.
New York, USA: Churchill Livingstone Inc, 1990: 369–395.
Chapter in a book:
Pessayre D, Feldmann G, Haouzi D, Fau D, Moreau A, Neumann M. Hepatocyte
apoptosis triggered by natural substances (cytokines, other endogenous molecules and
foreign toxins). In Cameron RG, Feuer G (editors): Apoptosis and its Modulation by
Drugs. Handbook of Experimental Pharmacology. Berlin: Springer-Verlag; 2000, pp.
59-108.
of a community-wide intervention to improve the delivery of preventive services to
children. Pediatrics [online serial] 2001; 108:e42.
http://www.pediatrics.org/cgi/content/full/108/3/e42. [Accessed 20 September 2001].
Tables
References to tables should be made in order of appearance in the text and should be in
Arabic numerals in parentheses, e.g. (Table 1). Each table should be typed on a separate
sheet in 1.5 spacing. Tables should not be submitted as photographs. Each table should
have a brief title as a heading. Vertical rules should not be used. Place explanatory
matter in footnotes, not in the heading. Authors are discouraged from using
abbreviations in tables. If abbreviations are necessary then please explain them in the
table’s footnotes. Identify statistical measures of variations, such as standard deviation
(SD) and standard error of the mean (SEM).
Be sure that each table is cited in the text. If you use data from another published or
for publication online only. See Supplemental Digital Content section for more details.
Figures
A) Creating Digital Artwork
1. Learn about the publication requirements for Digital Artwork:
http://links.lww.com/ES/A42
2. Create, Scan and Save your artwork and compare your final figure to the Digital
Artwork Guideline Checklist (below).
3. Upload each figure to Editorial Manager in conjunction with your manuscript text
and tables.
B) Digital Artwork Guideline Checklist
Here are the basics to have in place before submitting your digital artwork:
Artwork should be saved as TIFF, EPS, or MS Office (DOC, PPT, XLS) files.
High resolution PDF files are also acceptable.
resolution of at least 1200 dpi. If created in an MS Office program, send the
native (DOC, PPT, XLS) file.
Photographs, radiographs and other halftone images must be saved at a
resolution of at least 300 dpi.
Photographs and radiographs with text must be saved as postscript or at a
resolution of at least 600 dpi.
Each figure must be saved and submitted as a separate file. Figures should not
be embedded in the manuscript text file.
Remember:
References to figures should be made in order of appearance in the text and
should be in Arabic numerals in parentheses, e.g. (Fig. 2).
Number figures in the figure legend in the order in which they are discussed.
Upload figures consecutively to the Editorial Manager web site and enter figure
numbers consecutively in the Description field when uploading the files.
If hard copies are submitted they should have a label pasted to the back bearing
the illustration demands it, to a width of 166 mm.
Photomicrographs must have internal scale markers. If photographs of people
are used, their identities must be obscured or their written consent to use the
photograph must have been obtained. If necessary the Editors may request
copies of any consent forms.
If a figure has been published before, the original source must be acknowledged
and written permission from the copyright holder for both print and electronic
formats should be submitted with the material. Permission is required regardless
of authorship or publisher, except for documents in the public domain.
Figures may be reduced, cropped or deleted at the discretion of the editor.
Figure legends
Captions should be typed in 1.5 spacing, beginning on a separate page. Each figure
should be assigned an Arabic numeral, e.g. (Figure 3) and a brief title as a heading.
Internal scales should be explained and staining methods for photomicrographs should
Units of measurement
Scientific measurements should be given in SI units. Blood pressure, however, may be
expressed in mmHg and haemoglobin as g dL-1.
Abbreviations and symbols
Authors are discouraged from using abbreviations. If an abbreviation is necessary please
use only standard abbreviations. Avoid abbreviations in the title and abstract. The full
term for which an abbreviation stands should precede its first use in the text unless it is
a standard unit of measurement.
Supplemental Digital Content
Authors may submit supplemental digital content (SDC) to enhance their article’s text
and to be considered for online-only posting. SDC may include the following types of
content: text documents, graphs, tables, figures, graphics, illustrations, audio, and video.
On the Attach Files page of the submission process, please select Supplemental Audio,
placed in the call-out within the article. SDC files are not copy-edited by LWW staff,
they will be presented digitally as submitted. For a list of all available file types and
detailed instructions, please visit http://links.lww.com/A142.
SDC Call-outs
Supplemental Digital Content must be cited consecutively in the text of the submitted
manuscript. Citations should include the type of material submitted (Audio, Figure,
Table, etc.), be clearly labelled as "Supplemental Digital Content," include the
sequential list number, and provide a description of the supplemental content. All
descriptive text should be included in the call-out as it will not appear elsewhere in the
article.
For example:
We performed many tests on the degrees of flexibility in the elbow (see Video,
Supplemental Digital Content 1, which demonstrates elbow flexibility) and found our
A listing of Supplemental Digital Content must be submitted at the end of the
manuscript file. Include the SDC number and file type of the Supplemental Digital
Content. This text will be removed by our production staff and not be published.
For example:
Supplemental Digital Content 1.wmv
SDC File Requirements
All acceptable file types are permissible up to 10 MBs. For audio or video files greater
than 10 MBs, authors should first query the journal office for approval. For a list of all
available file types and detailed instructions, please visit http://links.lww.com/A142.
Reprints
Reprints may be purchased using the appropriate form that will be made available with
proofs. Orders should be sent when the proofs are returned; orders received after this
