Preoperative Evaluation of Patients with Obesity and Obstructive Sleep Apnea

Anesthesia for the Morbidly Obese Patient

Obesity is considered a major comorbidity, and it is imperative for an anesthesiologist to put increased emphasis on preoperative evaluation and perioperative management. A multidisciplinary team approach is the key for a successful outcome. This article encompasses basic tenets like pathophysiology and pharmacology pertaining to obesity. The authors also talk about important aspects of anesthesia care starting from preoperative assessment and optimization, intraoperative challenges and care, to recovery and discharge of these patients.

Preoperative Evaluation: Estimation of Pulmonary Risk Including Obstructive Sleep Apnea Impact

One in 4 deaths occurring within a week of surgery are related to pulmonary complications, making it the second most common serious morbidity after cardiovascular events. The most significant predictors of the postoperative pulmonary complications (PPCs) are American Society of Anesthesiologists physical status, advanced age, dependent functional status, surgical site, and duration of surgery. The overall risk of PPCs can be predicted using scores that incorporate readily available clinical data.

Short-term carbohydrate-restricted diet for weight loss in severely obese women

BACKGROUND

Weight loss in bariatric pre-surgery period reduces surgical complications, surgery time, blood loss, and length of hospital stay. Carbohydrate-restricted diets have been used as an alternative for weight loss. We tested the efficacy of a low-calorie carbohydrate-restricted diet (RD) for short-term weight loss in women with severe obesity and evaluate its metabolic effects in relation to a conventional low-calorie diet (CD).

METHODS

The subjects received a 1,200-kcal diet with or without carbohydrate restriction for a period of 1 week in the hospital. Nineteen obesity class III women were distributed into two groups: experimental (n = 10) and control (n = 9). The following variables were assessed at the beginning and end of the study: anthropometric measurements, body composition, resting energy expenditure, substrate oxidation, and biochemical tests.

RESULTS

Compared with CD, RD led to larger weight loss (2.6 and 4.4 kg, respectively; p = 0.01) and waist circumference reduction (p < 0.01). Among the assessed biochemical indicators, only plasma and urine acetone levels were different (p < 0.01); higher values were found in the experimental group with no symptoms and other diet-related complaints. There was also a significant decrease in triglycerides and carbohydrate oxidation, as well as a significant enhancement in lipid oxidation in the RD group.

CONCLUSION

Short-term RD was more efficient than CD regarding quick weight loss and waist circumference reduction, which may favor gastroplasty. Also, RD did not lead adverse metabolic effects.

Anaesthesia for bariatric surgery

Although many smaller studies have addressed anaesthetic care for bariatric surgical patients, comprehensive systematic literature reviews have yet to be compiled, and much evidence includes expert panel opinion. This review summarises study results in bariatric surgical patients regarding pre-anaesthesia evaluation, the perioperative impact of sleep-disordered breathing, airway management at anaesthetic induction and emergence, maintenance of anaesthesia, postoperative pain management, utility of clinical-care pathways and feasibility of outpatient bariatric surgery. The 'ramped' upper-body, reversed Trendelenburg position at anaesthetic induction and manual application of positive end-expiratory pressure (PEEP) is recommended. Intra-operative hypoxaemia can be treated with the combination of PEEP and recruitment manoeuvres, and attention to airway management at emergence is critical. Local anaesthetic wound infiltration and non-steroidal anti-inflammatory drugs should be part of multimodal opioid-sparing postoperative analgesia. Implementation of bariatric clinical-care pathways seems beneficial. Considering the prevalence of sleep apnoea in these patients, outpatient bariatric surgery remains controversial, but is probably safe for certain procedures, provided there is strict adherence to preoperative eligibility and home-care protocols.

Emergency department management of the airway in obese adults

Airway management in obese adults can be challenging, and much of the literature on this subject focuses on elective surgical cases, rather than acutely ill patients. In this article, we review the emergency department evaluation of the airway in obesity, discussing anatomy, physiology, and pharmacology. In addition, we describe techniques and devices used to improve intubating conditions in the obese patient. After our review of the relevant literature, we conclude that research in this particular area of acute care remains in its infancy.

Challenges in pulmonary risk assessment and perioperative management in bariatric surgery patients

Bariatric surgery has serious associated medical comorbidity and procedure-related risks and is, thus, considered an intermediate-to-high-risk non-cardiac surgery. Altered respiratory mechanics, obstructive sleep apnea (OSA), and less often, pulmonary hypertension and postoperative pulmonary embolism are the major contributors to poor pulmonary outcomes in obese patients. Attention to posture and positioning is critical in patients with OSA. Suspected OSA patients requiring intravenous narcotics should be kept in a monitored setting with frequent assessments and naloxone kept at the bedside. Use of reverse Tredelenburg position, preinduction, maintenance of positive end-expiratory pressure, and use of continuous positive airway pressure can help improve oxygenation in the perioperative period.

Apresentação clínica de pacientes obesos com diagnóstico polissonográfico de apnéia obstrutiva do sono

OBJETIVO: Avaliar a sintomatologia de pacientes obesos com diagnóstico polissonográfico de Síndrome da Apnéia/Hipopnéia Obstrutiva do Sono (SAHOS). MÉTODOS: Foram avaliados todos os pacientes obesos (IMC > 30 kg/m²) que realizaram polissonografia em dois laboratórios de sono da cidade de Salvador, BA, no período de julho a dezembro de 2004 e apresentaram Índice de Apnéia/Hipopnéia (IAH) > 5 ev/h/sono. Os sintomas considerados foram sonolência excessiva diurna, despertares noturnos, sensação de engasgos e/ou sufocamentos durante o sono. RESULTADOS: Foram incluídos 73 pacientes, sendo 57,5% do sexo masculino com média de idade e IMC de, respectivamente, 45,2 anos e 38,0 kg/m². A maioria (49,3%) foi classificada como SAHOS grave (IAH > 30). Os dados revelaram que 19,2% destes pacientes não apresentavam nenhum dos sintomas pesquisados, 28,8%, apenas um sintoma, 30,1%, dois e 21,9%, três. Não houve diferença estatisticamente significante em relação à gravidade da doença entre os indivíduos com e sem sintomas. Houve uma maior freqüência de pacientes assintomáticos entre os pacientes com obesidade severa (30,8% versus 5,9%; p = 0,007). CONCLUSÕES: A polissonografia parece ser um exame fundamental na avaliação de pacientes obesos devido à alta taxa de indivíduos assintomáticos com índices polissonográficos alterados neste grupo, em especial nos obesos graves.