[Lithotomy position: respiratory resistance with thiopental and propofol anesthesia].
OBJECTIVE
To study airway resistance changes induced by placement in lithotomy position under thiopentone and propofol anaesthesia.


METHODS
Prospective, randomised study.


METHODS
OR of a university hospital.


METHODS
Consecutive sample of 36 patients without bronchopulmonary disease (ASA 1-2; 18-78 yr.; 45-100 kg) scheduled for elective surgery in lithotomy position under general (mask) anaesthesia; oral premedication with 0.3 mg.kg-1 dipotassium chloroazeptate on the evening before and in the morning of surgery.


METHODS
Injection of either 4-6 mg.kg-1 thiopentone or 2-2.5 mg.kg-1 propofol into a fast running peripheral infusion until loss of eyelash reflex. Placement of an oropharyngeal airway and assisted ventilation via anatomic mask until recovery of spontaneous respiration. Oscilloresistometric determination (Siregnost FD 5; Siemens AG, Erlangen) of airway impedance (ROS) before and after placement in lithotomy position.


RESULTS
Before positioning ROS was 3.5 +/- 1.3 mbar.l-1.s-1 and 3.7 +/- 1.1 mbar.l-1.s-1 in the propofol and thiopentone group respectively. After positioning ROS was unchanged in the propofol group (3.8 +/- 1.8 mbar.l-1.s-1) and increased to 4.5 +/- 1.5 mbar.l-1.s-1 (p < 0.05) in the thiopentone group.


CONCLUSIONS
Lithotomy positioning induces an increase in airway impedance under thiopentone but not under propofol anaesthesia.
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Klinik und Poliklinik für Anästhesiologie und operative Intensivmedizin, Westfälischen Wilhelms-Universität Münster.
D000293:Adolescent; D000328:Adult; D000368:Aged; D000403:Airway Resistance / Q000187:drug effects* / Q000502:physiology; D000768:Anesthesia, General; D000771:Anesthesia, Intravenous; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015742:Propofol / Q000009:adverse effects; D011446:Prospective Studies; D016683:Supine Position / Q000502:physiology*; D013874:Thiopental / Q000009:adverse effects
D013874:Thiopental; D015742:Propofol
Steinschnittlagerung: Atemwegswiderstand unter Thiopental und Propofolanästhesie.