Survey of perioperative care of adults with obstructive sleep apnoea

Abstract

Editor, Obstructive sleep apnoea (OSA) involves frequent compromise of airway and respiration during sleep. The prevalence of adult OSA is approximately 5% and is associated with obesity [1,2]. Recent epidemiology shows increased obesity prevalence of 25% in UK adults [3]. The prevalence of OSA in surgical patients is about 9%, underestimated, increasing and associated with considerable risk of perioperative cardiorespiratory complications [4–6]. Sleep deprivation and sedatives aggravate the postoperative problems. There is controversy and inadequate evidence regarding the perioperative care of patients with OSA. A previous survey in Canada produced limited information [7]. Recent guidelines by the ASA are not widely accepted [8]. The aims of our survey are to examine UK practice, share experience, promote awareness and produce guidelines for perioperative care of patients with OSA. A postal questionnaire was designed to survey the opinions and clinical practice of anaesthetists regarding the perioperative care of adult patients with OSA. The questionnaire was based on literature evidence, ASA guidelines, controversies and local experience of the perioperative care of patients with OSA. It was distributed to 125 anaesthetists of consultant and registrar grades across three teaching hospitals and four general hospitals in Northwest England, UK. The survey was approved by the Pennine Acute Hospitals, Manchester, UK. The response rate was 45% (56/125). There were more consultant respondents (30/56; 54%) than there were registrars (26/56; 46%). The distribution of respondents' grade was similar between teaching hospitals and general hospitals. More than 93% were not aware of any perioperative management guidelines and 86% expressed support for the formation of UK guidelines. The annual frequency of perioperative care of OSA patients performed by anaesthetists was defined as rare (less than or equal to five cases), occasional (6–12 cases) and frequent (13 or more cases). Approximately 71% of consultants, 67% of teaching hospital registrars and 45% of general hospital registrars rarely anaesthetized patients with OSA. Only 15% anaesthetized patients with OSA frequently. In the preoperative screening of patients for OSA, more than 80% of respondents screened patients with a BMI of more than 30 kg m−2 or large neck circumference of 17 or more; 50% screened patients with craniofacial abnormality or tonsillar/thyroid enlargement; 60% of consultants and 40% of registrars screened patients with polycythaemia or ECG suggestive of right heart strain; and less than 8% screened hypertensive patients or all patients. More than 75% of respondents usually enquired about the symptoms of OSA, including snoring, witnessed apnoea, daytime somnolence and waking with choking feeling. About 70% of teaching hospital consultants enquired about morning headaches or poor concentration, compared with 50% of others. In patients with suspected OSA, more than 65% of respondents would conduct preoperative overnight oximetry, ECG and arterial blood gas analysis; 60% of consultants would request polysomnography (PSG); 40% of registrars would request PSG; and less than 35% of respondents would request echocardiography or chest radiography. About 70% of respondents were unaware of their regional PSG centre. Patients with OSA as the major morbidity were graded as ASA 3 by 70% of respondents and as ASA 2 by 30%. For the preoperative optimization of elective patients with OSA, more than 70% of respondents would optimize the patient's comorbidities, institute weight loss strategies, ensure a reduction in the patient's alcohol/sedative intake and institute continuous positive airway pressure (CPAP) if indicated by PSG. However, less than 14% would institute empirical CPAP or jaw devices preoperatively. Procedures considered appropriate for an 8 h day-stay by 61% were endoscopic, superficial, arthroscopic and ophthalmic surgery. About 40% considered inguinal/perineal surgery appropriate and less than 10% considered laparoscopy or airway surgery appropriate for day-stay. In patients with OSA not optimized for surgery, more than 80% would cancel major surgery, 50% would cancel laparoscopy and 26% would cancel arthroscopy. The preferred anaesthesia techniques for orthopaedic or peripheral surgery were central neuraxial block by more than 75%, nerve block by 40% and general anaesthesia by 10%. More than 85% administered supplemental oxygen to patients under regional anaesthesia. About 75% would not sedate patients with OSA undergoing regional anaesthesia and 65% would not use sedation as the sole technique for endoscopy. Before extubation, more than 80% would ensure reversal of neuromuscular block, adequate spontaneous respiration, full wakefulness and sitting posture, whereas less than 15% would ensure lateral posture or adequate blood gas analysis. The preferred modes of postoperative analgesia following orthopaedic or peripheral surgery included continuous catheter nerve block, epidural without opioid, nonsteroidal anti-inflammatory drug and local infiltration by more than 76% of respondents, epidural opioid or spinal opioid by 24% and parenteral opioid by 18%. Postoperatively, 84% of consultants monitored patients in a high-dependency unit (HDU), compared with 35% of registrars. About 59% of registrars monitored patients with continuous oximetry and telemetry, compared with 33% of consultants. About 65% of general hospital respondents monitored patients by extended stay in the recovery room, compared with 40% of teaching hospital respondents. Postoperatively, 86% of respondents provided supplemental oxygen to all patients, 14% provided oxygen as required and 40% re-instituted patients' CPAP. Perioperative complications previously encountered by proportions of respondents included difficult intubation in 34%, difficult ventilation in 47%, cardiovascular instability in 24%, difficult analgesia in 41%, difficult extubation in 13%, postoperative apnoea in 46%, reintubation in 27%, unplanned ICU admission in 23% and cardiac event in 25%. This is the first survey based on ASA guidelines for care of patients with OSA and the first to analyse the practice of perioperative care of patients with OSA in the UK (and Europe). The survey is relevant because of the obesity epidemic, the associated increased likelihood of anaesthetists encountering patients with OSA and the importance of assessing anaesthetists' desire or need for evidence-based guidelines. A previous survey from Canada had a response rate of 70% after reminders [7], but we had a response rate of 45% without using reminders. There was a similar response rate from teaching and general hospitals, but with more consultant respondents than registrars. It is possible that some responses may reflect local practice limitations secondary to availability of resources such as preoperative sleep studies, high-dependency beds and experts in obesity/OSA care, whereas some responses may reflect individual anaesthetist's preferences. Only 15% of our anaesthetists frequently anaesthetize patients with OSA, compared with 67% in the Canadian survey, and this may explain the different rate or type of responses. The low frequency may be related to underdiagnosis of OSA or referral to specialized units. Most of our anaesthetists were unaware of ASA guidelines despite their publication 18 months earlier, which highlights inadequate knowledge of OSA. However, similar to those in the Canadian survey, the anaesthetists in our study showed strong support for the formation of guidelines; partly because this may be perceived as potentially helpful to minimize adverse events encountered by 25–47% of respondents. There was wide variation in preoperative assessment and investigations, which reflects insufficient knowledge of OSA. The majority of our anaesthetists were unaware of their regional PSG centre, and this implies underutilization of available resources due to inadequate knowledge or information. These problems may be corrected easily by local education and information dissemination. In accordance with ASA guidelines, we recommend robust preoperative assessment and early perioperative planning for patients with known or suspected OSA, in collaboration with surgeons and other members of the perioperative team. Our survey revealed an overwhelming agreement that patients with OSA should be classified as ASA 3, preoptimized before elective surgery, have major surgery postponed if not optimized and day-case procedures limited to peripheral surgery. Although this well tolerated approach is recommended, it should be noted that it can potentially aggravate the pressure on hospital resources or performance; and we recommend a risk–benefit analytical management of individual cases. It is encouraging that the vast majority of responses regarding anaesthesia care were in keeping with ASA guidelines, with a general preference for regional anaesthesia over general anaesthesia and the use of opioid-sparing analgesia if possible. There is good evidence to support the benefits of this practice, which should be encouraged among anaesthetists. Postoperative monitoring, respiratory support and oxygen therapy were mostly in accordance with ASA guidelines; although there is room for improvement. The preference for the location of postoperative care was varied, with registrars preferring surgical wards with continuous oximetry and telemetry; unlike consultants, who preferred HDU monitoring. However, HDU monitoring may be excessive, unnecessary and should be employed judiciously because of costs. The location of postoperative care is not as important as ensuring continuous pulse oximetry in patients with OSA. Overall, our anaesthetists showed considerable agreement on anaesthesia care and analgesia, but there was discrepancy in preoperative assessment and postoperative care of patients with OSA. There was strong support for establishing UK guidelines, which would be especially beneficial in the areas of discrepancy. However, there is also a need for further research into these areas to help clarify the benefits of certain investigations and practices such as routine PSG and HDU monitoring.