Preoxygenation in pediatric patients

BACKGROUND: Preoxygenation with tidal volume breathing for 3 min is a standard technique using 100% oxygen for prevention of hypoxia during the induction of general anesthesia. The measurement of end tidal oxygen concentration is useful in preoxygenation monitoring. The aim of the study was to determine the effects of preoxygenation in pediatric patients during 3 min with tidal volume breathing. METHODS: Sixty patients who were scheduled for general surgery were divided into 0-6 yr old children (Group I, n = 20), 7-15 yr old children (Group II, n = 20) and adults (Group III, n = 20). Patients with an inflatable mask connected to an anesthesia machine breathed 100% oxygen spontaneously for 3 min with tidal volume in all three groups. End tidal oxygen concentration, end tidal carbon dioxide concentration and respiratory rate were measured simultaneously for 3 min. RESULTS: Group I and II showed significantly higher end tidal oxygen concentrations than Group III from 10 sec to 160 sec with 3 min tidal volume breathing (P < 0.05). The mean time required for end tidal oxygen concentration of 90% was 85.5 +/- 18.5 sec for Group I, 101.5 +/- 21.5 sec for Group II and 148.0 +/- 24.0 sec for Group III. Therefore, Group I and II showed a significantly shorter time than Group III (P < 0.05). CONCLUSIONS: Pediatric patients showed a significantly shorter time to obtain the required preoxygenation.

Comparison of the effects of preoxygenation between pregnant and non-pregnant patients

BACKGROUND: Preoxygenation is a standard anesthetic technique using 100% oxygen for the prevention of hypoxia during the induction of anesthesia. Measuring end-tidal oxygen is the most useful indicator for determining the end-point of preoxygenation. We studied the effects of preoxygenation between pregnant and non-pregnant patients during 5 min of tidal volume breathing. METHODS: Non-pregnant women who were scheduled for general surgery (Group I, n = 25) and pregnant women who were scheduled for elective cesarean section (Group II, n = 20) were explained the technique of preoxygenation, which was conducted with 100% oxygen during 5 min of tidal volume breathing. End-tidal oxygen concentration was measured at 10 sec intervals for 5 min, simultaneously. RESULTS: Group II showed significantly higher end-tidal oxygen concentration than Group I from 30 sec to 170 sec during preoxygenation (P or =90% was 110.0 +/- 31.7 sec for Group II and 152.8 +/- 34.5 sec for Group I. Therefore, Group II showed a significantly shorter time than Group I (P < 0.05). CONCLUSIONS: We concluded that the time for complete preoxygenation was shorter in pregnant patients compared to non-pregnant patients.

The effect of pyridostigmine on bispectral index during recovery from sevoflurane anesthesia / 대한마취과학회지

BACKGROUND: There have been some conflicting reports showing that muscle relaxants and anticholinesterases affect the level of the bispectral index (BIS). The purpose of this study was to investigate whether pyridostigmine affects the level of the BIS during recovery from sevoflurane anesthesia. METHODS: Fifty-two adult patients scheduled for laparoscopic cholecystectomy and laparoscopic appendectomy. Anesthesia was induced with thiopental 4 mg/kg and rocuronium 0.6 mg/kg. The lung was mechanically ventilated with 1-3 vol% sevoflurane, 50% oxygen and 50% nitrous oxide. After a specimen was removed, the sevoflurane concentration was maintained at 1.5 vol%. When skin closure began, sevoflurane was stopped; however, 50% oxygen and 50% nitrous oxide were maintained. The patients then received either (1) a group that received an injection of glycopyrrolate 0.04 mg/kg and pyridostigmine 0.2 mg/kg (reverse (R) group, n = 26) or (2) a group that received normal saline (control (C) group, n = 26). Group assignment was random. Pyridostigmine, a reversible cholinesterase inhibitor, is a parasympathomimetic. End-tidal sevoflurane concentration, train of four (TOF) ratio, bispectral index (BIS), blood pressure and heart rate were measured from the end of the operation to 15 min after inject of pyridostigmine or placebo. RESULTS: There were no significant between group differences in the time dependent decrease in end-tidal sevoflurane concentration (P = 0.0642). There were significant differences between the two groups for the time course for increases in the TOF value (P < 0.0001). There were significant differences between the two groups for the time course for increases in the BIS value (P = 0.0107). There were no significant differences in the mean BIS value up to 10 minutes after administering drug, but 15 minutes after administrating the reverse drug or the control drug, the BIS value showed significantly different BIS values: 68.2 +/- 6.2 (Group R) and 63.2 +/- 6.2 (Group C) (P = 0.0058). CONCLUSIONS: The finding that pyridostigmine increases TOF and BIS suggests that pyridostigmine may enhance recovery during recovery from sevoflurane anesthesia.