Effects of pneumoperitoneal pressure and position changes on respiratory mechanics during laparoscopic colectomy.

BACKGROUND: This study was designed to assess the effects of pneumoperitoneal pressure (PP) and positional changes on the respiratory mechanics during laparoscopy assisted colectomy. METHODS: Peak inspiratory pressure, plateau pressure, lung compliance, and airway resistance were recorded in PP of 10 mmHg and 15 mmHg, with the position change in 5 steps: head-down at 20°, head-down at 10°, neutral position, head-up at 10° and head-up at 20°. RESULTS: When the patient was placed head-down, the position change accentuated the effects of pneumoperitoneum on respiratory mechanics. However, when the patient was placed in a head-up position during pneumoperitoneum the results showed no pattern. In the 20° head-up position with the PP being 10 mmHg, the compliance increased from 30.6 to 32.6 ml/cmH(2)O compared with neutral position (P = 0.002). However with the PP being 15 mmHg, the compliance had not changed compared with neutral position (P = 0.989). In 20° head-down position with the PP of 10 mmHg, the compliance was measured as 24.2 ml/cmH(2)O. This was higher than that for patients in the 10° head-down position with a PP of 15 mmHg, which was recorded as 21.2 ml/cmH(2)O. Also in the airway resistance, the patient in the 20° head-down position with the PP of 10 mmHg showed 15.8 cmH(2)O/L/sec, while the patient in the 10° head-down position with the PP of 15 mmHg showed 16.2 cmH(2)O/L/sec of airway resistance. These results were not statistically significant but still suggested that the head-down position accentuated the effects of pneumoperitoneum on respiratory mechanics. CONCLUSIONS: Our results suggest that respiratory mechanics are affected by the patient position and the level of PP - the latter having greater effect.

A comparison of hemodynamic changes after endotracheal intubation by the Optiscope™ and the conventional laryngoscope.

BACKGROUND: Optiscope™ is a newly developed video stylet device. This study evaluated and compared the hemodynamic changes observed after endotracheal intubation with video stylet and after conventional laryngoscopic endotracheal intubation. METHODS: Fifty-eight adult patients with American Society of Anesthesiologists (ASA) physical status class 1 or 2, undergoing general anesthesia, were randomized into two groups: one group of patients were intubated using video stylet (n = 29) and the other group were intubated using direct laryngoscope (n = 29). Systolic blood pressure (SBP), mean arterial pressure (MAP), diastolic blood pressure (DBP), heart rate (HR), POGO (percentage of glottic opening) score, time for intubation and degree of sore throat were recorded. RESULTS: There were no significant differences in the SBP, MAP, DBP, HR, and the sore throat incidence between the two groups. Optiscope™ produced better POGO scores, but time for intubation was longer than with conventional laryngoscope. CONCLUSIONS: Optiscope™, when compared with conventional laryngoscope for intubation, does not modify the hemodynamic response, but it provides a better view of the vocal cords.