Ventilatory response to CO2 following intravenous ketamine in children.
The effects of intravenous ketamine (bolus of 2 mg.kg-1 followed by a continuous infusion at a rate of 40 micrograms.kg-1.min-1) on ventilatory response to carbon dioxide were studied in nine children ranging in age from 6 to 10 yr and in weight from 20 to 48 kg. Ketamine did not affect resting respiratory rate, tidal volume, end-tidal CO2 tension (PETCO2), or minute ventilation. Five minutes after the ketamine bolus, the slope VE/PETCO2 decreased significantly (P less than 0.05) from 1.71 +/- 0.47 to 1.05 +/- 0.23 1.min-1.mmHg-1 (mean +/- SD). After 30 min of continuous iv ketamine infusion, the slope returned to 1.65 +/- 0.44 1.min-1.mmHg-1, a significantly higher value (P less than 0.05) compared with the nadir and not significantly different from control. The minute ventilation at a PETCO2 of 60 mmHg decreased from 824 +/- 98 to 626 +/- 26 ml.kg-1.min-1 5 min after iv ketamine, and remained depressed (640 +/- 125 ml.kg-1.min-1 P less than 0.05) throughout the 30-min ketamine infusion. In addition, the slope VT/PETCO2 and the VT 60 did not change during the study; nonetheless, the slope f/PETCO2 and the f 60 decreased significantly following iv bolus ketamine, and the f 60 remained significantly decreased following ketamine infusion. The authors conclude that clinically useful doses of iv ketamine significantly alter ventilatory control in children.
Hamza
J
J
Department of Anesthesiology, Bicêtre Hospital, Université Paris-Sud, France.
Ecoffey
C
C
Gross
J B
JB
D000704:Analysis of Variance; D000771:Anesthesia, Intravenous / Q000379:methods; D002245:Carbon Dioxide / Q000502:physiology*; D002648:Child; D003864:Depression, Chemical; D004341:Drug Evaluation; D006801:Humans; D007649:Ketamine / Q000008:administration & dosage / Q000009:adverse effects; D012119:Respiration / Q000187:drug effects*; D012129:Respiratory Function Tests
D002245:Carbon Dioxide; D007649:Ketamine