Apnoeic oxygenation in morbid obesity: a randomised controlled trial comparing facemask and high-flow nasal oxygen delivery.

BACKGROUND: Obesity is a risk factor for airway-related incidents during anaesthesia. High-flow nasal oxygen has been advocated to improve safety in high-risk groups, but its effectiveness in the obese population is uncertain. This study compared the effect of high-flow nasal oxygen and low-flow facemask oxygen delivery on duration of apnoea in morbidly obese patients. METHODS: Morbidly obese patients undergoing bariatric surgery were randomly allocated to receive either high-flow nasal (70 L min-1) or facemask (15 L min-1) oxygen. After induction of anaesthesia, the patients were apnoeic for 18 min or until peripheral oxygen saturation decreased to 92%. RESULTS: Eighty patients were studied (41 High-Flow Nasal Oxygen, 39 Facemask). The median apnoea time was 18 min in both the High-Flow Nasal Oxygen (IQR 18-18 min) and the Facemask (inter-quartile range [IQR], 4.1-18 min) groups. Five patients in the High-Flow Nasal Oxygen group and 14 patients in the Facemask group desaturated to 92% within 18 min. The risk of desaturation was significantly lower in the High-Flow Nasal Oxygen group (hazard ratio=0.27; 95% confidence interval [CI], 0.11-0.65; P=0.007). CONCLUSIONS: In experienced hands, apnoeic oxygenation is possible in morbidly obese patients, and oxygen desaturation did not occur for 18 min in the majority of patients, whether oxygen delivery was high-flow nasal or low-flow facemask. High-flow nasal oxygen may reduce desaturation risk compared with facemask oxygen. Desaturation risk is a more clinically relevant outcome than duration of apnoea. Individual physiological factors are likely to be the primary determinant of risk rather than method of oxygen delivery. CLINICAL TRIAL REGISTRATION: NCT03428256.

The use of high-dose intrathecal diamorphine in laparoscopic bariatric surgery: a single-centre retrospective cohort study.

INTRODUCTION: The use of intrathecal diamorphine is not commonplace in laparoscopic bariatric surgery. At our institution, a major UK bariatric centre, high-dose intrathecal diamorphine is routinely utilised. METHODS: Data were analysed retrospectively. Fifty-three patients who had a spinal anaesthetic were matched against age, sex, body mass index and surgical procedure type to generate controls. Pain scores were recorded in the post-anaesthetic care unit on arrival, after 1 hour and on discharge to the ward. Post-operative nausea and vomiting; post-operative hypertension; pruritus; 24-hour morphine consumption and length of stay were measured. RESULTS: Pain scores were better in the spinal anaesthetic group in all measured categories (p = 0.033, p < 0.01, p < 0.01); post-operative nausea and vomiting was less common in the spinal anaesthetic group (p < 0.01); post-operative hypertension was less common in the spinal anaesthetic group (p = 0.25); pruritus was more common in the spinal anaesthetic group (p < 0.01); morphine consumption was less common in the spinal anaesthetic group (p = 0.037). Length of hospital stay was reduced by 12.4 hours (p = 0.025). CONCLUSION: We propose that this is a practical and safe technique to adopt. A randomised-control trial will need to be conducted in order to find the most efficacious volume of local anaesthetic and dose of diamorphine.

Anaesthetic Preparation of Obese Patients: Current Status on Optimal Work-up.

PURPOSE OF REVIEW: With the prevalence of obesity rapidly growing, bariatric anaesthesia becomes everyday anaesthesia rather than a subspecialty. In this review, we are aiming to draw attention to this complex group of patients and their comorbidities, relevant to everyday practice for contemporary anaesthetists. RECENT FINDINGS: We wanted to focus greatly on sleep-related breathing disorders, because preoperative screening, diagnosis and treatment of the aforementioned make a huge impact in the improvement of preoperative morbidity and mortality, including positive effects on the cardiovascular system. The overview is touching on main obesity-related comorbidities and guides the anaesthetist and associated health professionals on how to approach and manage them. A multidisciplinary approach widely used in bariatric care may be adopted in the care of obese patients in order to reduce preoperative morbidity and mortality. We advocate the early involvement of the anaesthetic team in the preoperative assessment of obese patients in order to achieve appropriate risk stratification and optimise the care.