No abstract

SummaryThe aim of the study was to evaluate leakage of liquid past the low-pressure cuffs of tracheal tubes. Ten samples of each of nine different types of tubes were tested in a PVC mock trachea, using intracuff pressures of 20, 30, 40 and 50 cmH 2 O. In five types of tubes, 6-10 cuffs allowed profuse leakage (> 20 ml water in 5 min) even at the highest intracuff pressure, i.e. 50 cmH 2 O. In the most efficient tube, all the cuffs were leak-proof (leakage < 5 ml in 5 min) at 40 cmH 2 O and in the second best type the cuffs were leak-proof at 50 cmH 2 O. The leakage of fluid past the tracheal tube remains an unresolved problem with low-pressure cuffs.

The effects on corrected QT interval (QTc), heart rate and arterial pressure were studied after induction with propofol 1.5, 2 or 2.5 mg.kg-1, thiopentone 5 mg.kg-1 or methohexitone 2 mg.kg-1 in 123 ASA class I or II children undergoing outpatient otolaryngological surgery. Premedication consisted of oral midazolam and atropine. The children were randomly allocated to one of the three propofol groups or to the thiopentone or methohexitone group. After injection of the intravenous anaesthetic, the QTc interval was significantly prolonged after propofol 2.5 mg.kg-1. Thirty seconds after suxamethonium 1.5 mg.kg-1, a significant prolongation of the QTc interval occurred in the thiopentone and propofol 1.5 and 2 mg.kg-1 groups. After intubation, no further prolongation of the QTc interval occurred in any of the groups. Heart rate increased significantly after the barbiturates but not after propofol. Systolic arterial pressure decreased significantly after propofol 1.5 and 2.5 mg.kg-1. In all groups a cardiovascular intubation response occurred. Bradycardia and junctional rhythm occurred in 4% of the children in both barbiturate groups and in 19-29% in the propofol groups. It is concluded that propofol causes prolongation of the QT interval and results in a higher incidence of bradycardia and junctional rhythm than the barbiturates.

In order to quantify changes in total respiratory compliance (Crs) Pressurization of the peritoneal cavity for laparoscopic surgery effects an abrupt decrease in total respiratory compliance (CrO, mainly resulting from a decrease in thoracic compliance. 1 Breath by breath monitoring of C~ is made convenient by a commercial side stream spirometry device. 2 In order to assess the changes in C~s coinciding with CO2 insufflation and deflation, we recorded the readings in patients, scheduled for laparoscopic cholecystectomy, fundoplication, and inguinal hernia repair. Our assumption was that C_~ would remain decreased after deflation, as described after gynaecological laparoscopy.3,4 Such a decrement might disturb postoperative respiration. MethodsThe study was approved by the local Ethics committee. We recorded the readings of C~ in 32 successive adult ASA 1-2 patients undergoing laparoseopic surgery. The patients were categorized according to the procedure in order to assess the effect of position and that of varying insufflation pressures and duration of pressurization, as necessittted by different surgery: C = cholecystectomy, CAN J ANAESTH 1995 / 42: 6/pp495-7