Comparative evaluation of propofol 350 and 200 mg for induction of anaesthesia in morbidly obese patients: a randomized double-blind pilot study.

BACKGROUND AND OBJECTIVE: The aim of this pilot study was to evaluate efficacy and safety of propofol 350 versus 200 mg for induction of anaesthesia in morbidly obese patients undergoing bariatric surgery. PATIENTS AND METHODS: Twenty morbidly obese patients (BMI range 38-60 kg m) were randomized to receive propofol 350 or 200 mg over 60 s for induction of anaesthesia. Bispectral index (BIS) values, induction characteristics and haemodynamic parameters were compared. RESULTS: At the time of intubation, in the 200 mg group, mean BIS values were more variable and significantly higher [53 (range 27-86) versus 31 (range 18-52), 200 versus 350 mg group (P = 0.01)]. In 20% of the 200 mg group, an additional propofol dose was needed, whereas no additional doses were judged necessary in the 350 mg group. At the time of intubation, six patients in the 200 mg group had systolic arterial pressures above 160 mmHg [mean 162 (range 100-210)], whereas mean pressures in the first 10 min were more in the target range in the 350 mg group [mean 122 (range 90-170)] (P = 0.01). One patient in the 350 mg group experienced a serious decrease in systolic arterial pressure (below 60 mmHg), immediately upon starting the maintenance dose. There were no significant differences in heart rate. CONCLUSION: Although propofol 200 mg proved to be an inadequate induction dose for morbidly obese patients, the 350 mg induction dose deserves further study, provided the maintenance dose is not started within 5 min, thereby preventing temporary cardiovascular instability.

Time to wean after tracheotomy differs among subgroups of critically ill patients: retrospective analysis in a mixed medical/surgical intensive care unit.

OBJECTIVE: To determine the time to wean from mechanical ventilation and time spent off the ventilator per day after tracheotomy in critically ill patients in a 28-bed mixed medical and surgical intensive care unit (ICU) in Amsterdam, Netherlands. METHODS: We conducted a retrospective analysis of consecutive patients during the 14-month period from November 1, 2003, through January 1, 2005. Included were translaryngeally intubated mechanically ventilated patients who received a tracheotomy during their ICU stay. RESULTS: Of all the patients admitted to the ICU, 129 (7%) received a tracheotomy. Significantly more tracheotomies were performed in neurosurgery/neurology patients and in those admitted for acute conditions (16% and 12%, respectively). Tracheotomy was performed a median 8 days (interquartile range 4-13 d) after ICU admission. For all the patients, the median time to wean after tracheotomy was 5 days (interquartile range 2-11 d). Neurosurgery/neurology patients and patients in the cardiology subgroup needed significantly less time to wean from mechanical ventilation than did patients in other subgroups (3 d, interquartile range 2-7 d, and 3 d, interquartile range 2-5 d, respectively, p < 0.05). There was a significant association between admission group and neurological status at the time of tracheotomy. A low Glasgow coma scale score was associated with shorter time to wean. Within 1 week after tracheotomy, the probability of the patient having breathed spontaneously, without ventilator assistance, for > 4 h/d was 89%, 78% for > 8 h/d, and 72% for > 12 h/d. By day 28, the probability of the patient having breathed spontaneously for > 4 h/d was 98%, 97% for > 8 h/d, and 94% for > 12 h/d. CONCLUSION: Time to wean from after tracheotomy differed among the subgroups in our ICU. After tracheotomy, the majority of patients were quickly able to breathe spontaneously without assistance of the mechanical ventilator for several hours per day. Patients who require tracheotomy only for airway protection wean sooner than other patients.