The effects of abdominal opening on respiratory mechanics during general anaesthesia for open bariatric surgery in morbidly obese patients.

BACKGROUND: Morbid obesity BMI 40 kg mL-2 is associated with several changes in anatomy and physiology of the respiratory system. Respiratory work is increased whereas compliance of the chest wall and lungs is decreased. Increased intra-abdominal pressure compresses the diaphragm and reduces its movability. Abdominal opening should influence respiratory mechanics. METHODS: Forty-seven morbidly obese patients (BMI 49.54 ± 7.21 kg m-2) scheduled for elective bariatric surgery (open Roux-en-Y-Gastric Bypass - RYGB) were included in the study and divided into 3 groups: 40< BMI <50, 50< BMI <60 and BMI >60. Measurements were performed during general anaesthesia at two time points: before (T1) and after abdominal opening (T2). All patients were ventilated using the volume control mode. RESULTS: Preoperative spirometry revealed significantly decreased FEV 1% in the BMI >60 group. The conditions of mechanical ventilation during general anaesthesia deteriorated with an increasing BMI. After abdominal opening,the mechanical ventilation conditions improved: increased lung compliance and decreased airway pressures. The difference was statistically significant in the entire population studied. After dividing the population into groups, however, the difference was no longer significant in patients with BMI >60. The most significant difference in peak and plateau pressures after abdominal opening was observed in patients with BMI <50. CONCLUSION: Abdominal opening improves the conditions of mechanical ventilation in morbidly obese patients; when BMI is over 60 kg m-2, this improvement may not be relevant.

A Comparison of a Standard Macintosh Blade Laryngoscope, Pentax-AWS Videolaryngoscope and Intubrite Videolaryngoscope for Tracheal Intubation in Manikins in Sitting and Prone Positions: A Randomized Cross-Over Study.

BACKGROUND: Intubation of a patient in different positions may be done not only in emergency settings, but also in routine anesthesia (e.g., prone position for lumbar spine surgery). METHODS: The aim of the study was to compare the classic Macintosh blade laryngoscope with two videolaryngoscopes: the Pentax-AWS and the Intubrite in a simulated scenario of a manikin placed in a sitting and prone position. Additionally, intubation with the use of all three devices was performed in a standard supine position as the control group. The time of intubation and the pressure exerted on the tongue was assessed. The ANOVA Friedman (analysis of variance) and Wilcoxon with Bonferroni correction tests were used for statistical analysis. RESULTS: The time of intubation in a prone position was significantly shorter for the Pentax-AWS videolaryngoscope compared to the Macintosh and the Intubrite. There were no significant differences in the obtained results of the evaluated devices in sitting and standard positions. The lowest pressure exerted on the tongue was with the Pentax-AWS, followed by the Intubrite and the Macintosh laryngoscopes. CONCLUSIONS: The use of the Pentax-AWS was associated with faster tracheal intubation, creating lower pressure on tongue when compared with standard Macintosh and Intubrite laryngoscopes in both prone and sitting positions.

Post-anesthesia recovery after infusion of propofol with remifentanil or alfentanil or fentanyl in morbidly obese patients.

BACKGROUND: The type of opioid used during general anesthesia in the morbidly obese influences recovery and the postoperative period. In a randomized clinical trial, the postoperative recovery profile and early period after general anesthesia with remifentanil, fentanyl and alfentanil were compared in morbidly obese patients. MATERIAL AND METHOD: 60 morbidly obese patients with BMI >35 kg/m(2) (mean 43.31) undergoing open Roux-en-y gastric bypass were randomly divided into 3 groups: remifentanil (R), fentanyl (F), and alfentanil (A). Dosage of opioids was based on ideal body weight (IBW): fentanyl 5 mcg/kg for intubation followed by infusion of 0.025-0.05 mcg/kg/min; alfentanil 15 mcg/kg initially, then 1.0-1.5 mcg kg/min; and remifentanil 1 mcg/kg followed by infusion of 0.25-1.5 mcg/kg/min. Anesthesia was induced with infusion of propofol and oxygen with N(2)O (1:1). After anesthesia, the duration to response to verbal command, spontaneous respiration, adequate respiration, and safe extubation were recorded. The incidence of postoperative nausea and vomiting were recorded. Using verbal scale for evaluation of postoperative pain, the early postoperative analgesia requirements were assessed. RESULTS: Demographic profiles and duration of procedure did not differ between groups. A total dose of propofol was significantly lower in Group R compared with Groups A and F (P <0.05). Duration to spontaneous respiration, adequate respiration and safe extubation were significantly shorter in Group R compared with Group F (P <0.05). Shortly after anesthesia, significantly more patients in Group R required additional dose of analgesic than in Group F (P <0.05). Postoperative nausea and vomiting (PONV) occurred significantly more often in Group R compared with Group F (P <0.05). Recovery profile of Group A was more similar to Group R, and postoperative pain and PONV evaluation more similar to Group F. CONCLUSION: In morbidly obese individuals, alfentanil or fentanyl and remifentanil can be safely used, but there is a higher rate of PONV and postoperative pain in the remifentanil group.