The association of pre-operative STOP-BANG scores with postoperative critical care admission.

The STOP-BANG questionnaire screens for obstructive sleep apnoea. We retrospectively analysed the independent association of pre-operative variables with postoperative critical care admission using multivariable logistic regression for patients undergoing elective surgery from January to December 2011. Of 5432 patients, 338 (6.2%) were admitted postoperatively to the critical care unit. In multivariate analysis, the odds ratios (95% CI) for critical care admission were: 2.2 (1.1-4.6), p = 0.037; 3.2 (1.2-8.1), p = 0.017; and 5.1 (1.8-14.9), p = 0.002, for STOP-BANG scores of 4, 5 and ≥ 6, respectively. The odds ratio was also independently increased for: each year of age, 1.015 (1.004-1.026), p = 0.019; asthma, 1.6 (1.1-2.4), p = 0.016; obstructive sleep apnoea, 3.2 (1.9-5.6), p < 0.001; and for ASA physical status 2, 3 and ≥ 4, 2.1 (1.4-3.3), 6.5 (3.9-11.0), 6.3 (2.9-13.8), respectively, p < 0.001 for all.

Accuracy of ProSeal™ laryngeal mask airway intracuff pressure estimation using finger palpation technique - a prospective, observational study.

The incidence of pharyngolaryngeal adverse events associated with laryngeal mask airways can be reduced by the use of manometry to limit the laryngeal mask airway intracuff pressures. We conducted a prospective, observational study in 80 patients undergoing general anaesthesia with the ProSeal™ laryngeal mask airway to determine the accuracy of a finger palpation technique compared to actual readings obtained from a hand-held manometer by different anaesthesia personnel. The strength of association of estimated versus actual intracuff pressures, R, for nurse anaesthesia assistants, junior anaesthetists and senior anaesthetists were 0.21 (weak), 0.35 (moderate) and 0.78 (strong) respectively. Subgroup analysis showed that anaesthetists with more than three years of experience were more accurate than those with less than three years of experience. The actual versus estimated intracuff pressures were 4±17 vs 19±27 cmH2O (P value <0.001) respectively. In all groups, the palpation technique tended to underestimate the actual intracuff pressure by a mean of 10.3 cmH2O. Palpation accuracy decreased when actual intracuff pressures were >80 cmH2O. These findings suggest that cuff pressure manometry should be recommended as standard of care with the use of laryngeal mask airways.

Perioperative risk factors in obese patients for bariatric surgery: a Singapore experience.

INTRODUCTION: Morbid obesity and obstructive sleep apnoea (OSA) are increasingly encountered in anaesthetic practice today. Difficult intubation may be seen more frequently in our practice. This high-risk group may also be more prone to complications in the postoperative period. METHODS: We reviewed a consecutive series of patients who had undergone laparoscopic gastric banding at our institution from 2001 to 2006. The incidence of difficult intubation, early postoperative complications and its attendant risk factors were studied. RESULTS: Severe OSA and neck circumference greater than 44 cm were factors associated with difficult intubation in morbidly obese patients who presented for bariatric surgery. Asthma and increasing age may be associated risk factors for adverse events in the postoperative period. CONCLUSION: It is important to anticipate and prepare for a difficult intubation scenario in patients with severe OSA and a larger neck circumference. Close monitoring is recommended for patients with respiratory comorbidities and advanced age.

A comparison of 5% dextrose in 0.9% normal saline versus non-dextrose-containing crystalloids as the initial intravenous replacement fluid in elective surgery.

Intravenous fluid replacement in adult elective surgery is often initiated with dextrose-containing fluids. We sought to determine if this practice resulted in significant hyperglycaemia and if there was a risk of hypoglycaemia if non-dextrose-containing crystalloids were used instead. We conducted a randomized controlled trial in 50 non-diabetic adult patients undergoing elective surgery which did not involve entry into major body cavities, large fluid shifts, or require administration of >500 ml of intravenous fluid in the first two hours of peri-operative care. Patients received 500 ml of either 5% dextrose in 0.9% normal saline, lactated Ringer's solution, or 0.9% normal saline over 45 to 60 minutes. Plasma glucose, electrolytes and osmolarity were measured prior to infusion, and at 15 minutes and one hour after completion of infusion. None of the patients had preoperative hypoglycaemia despite average fasting times of almost 13 hours. Patients receiving lactated Ringer's and normal saline remained normoglycaemic throughout the study period. Patients receiving dextrose saline had significantly elevated plasma glucose 15 minutes after completion of infusion (11.1 (9.9-12.2, 95% CI) mmol/l). Plasma glucose exceeded 10 mmol/l in 72% of patients receiving dextrose saline. There was no significant difference in plasma glucose between the groups at one hour after infusion, but 33% of patients receiving DS had plasma glucose > or = 8 mmol/l. We conclude that initiation of intravenous fluid replacement with dextrose-containing solutions is not required to prevent hypoglycaemia in elective surgery. On the contrary, a relatively small volume of 500 ml causes significant, albeit transient, hyperglycaemia, even in non-diabetic patients.