Blouin R T, Seifert H A, Babenco H D, Conard P F, Gross J B
Department of Anesthesiology, University of Connecticut School of Medicine, Farmington 06030.
Anesthesiology. 1993 Dec;79(6):1177-82. doi: 10.1097/00000542-199312000-00007.
Propofol infusion at subanesthetic doses provides reliable conscious sedation. However, the ventilatory effects of sedative doses of propofol have not been established. The current study was conducted to determine the effects of propofol sedation on the hypoxic ventilatory response.
Eight healthy, male volunteers received 1 mg.kg-1 propofol followed by a propofol infusion adjusted to maintain a constant, subanesthetic level of sedation. Hypoxic ventilatory response was measured using an isocapnic rebreathing technique: while keeping PETCO2 constant (approximately 6 mmHg above prestudy baseline), the authors continuously recorded minute ventilation and tidal volume, as oxygen saturation (SpO2) decreased from 98 to 70%. Hypoxic response determinations were performed before and during propofol infusion, as well as 30 and 60 min after termination of the propofol infusion.
The slope of the hypoxic ventilatory response curve (VE vs. SpO2) decreased from 0.88 +/- 0.15 to 0.17 +/- 0.03 l.min-1.%SpO2 -1 during propofol sedation (mean +/- SE). Thirty minutes after discontinuation of the propofol infusion, slope returned to its prepropofol value. In addition, minute ventilation at SpO2 = 90% decreased during propofol sedation, from 16.1 +/- 0.8 to 8.7 +/- 0.4 l.min-1, accompanied by a similar decrease in tidal volume at SpO2 = 90%, from 1,099 +/- 87 to 523 +/- 21 ml. Thirty minutes after discontinuation of the propofol infusion, these variables also returned to their prepropofol values.
The authors concluded that propofol infusion for conscious sedation significantly decreases the slope and causes a downward shift of the hypoxic ventilatory response curve measured during isohypercapnia.
亚麻醉剂量的丙泊酚输注可提供可靠的清醒镇静。然而，镇静剂量的丙泊酚对通气的影响尚未明确。本研究旨在确定丙泊酚镇静对低氧通气反应的影响。
八名健康男性志愿者先接受1mg·kg-1的丙泊酚，随后进行丙泊酚输注，调整输注速度以维持恒定的亚麻醉镇静水平。使用等碳酸氧再呼吸技术测量低氧通气反应：在使呼气末二氧化碳分压（PETCO2）保持恒定（比研究前基线高约6mmHg）的同时，当氧饱和度（SpO2）从98%降至70%时，作者持续记录分钟通气量和潮气量。在丙泊酚输注前、输注期间以及丙泊酚输注结束后30分钟和60分钟进行低氧反应测定。
在丙泊酚镇静期间，低氧通气反应曲线（分钟通气量与SpO2）的斜率（平均值±标准误）从0.88±0.15降至0.17±0.03l·min-1·%SpO2-1。丙泊酚输注停止30分钟后，斜率恢复到输注前的值。此外，在丙泊酚镇静期间，SpO2 = 90%时的分钟通气量从16.1±0.8降至8.7±0.4l·min-1，同时SpO2 = 90%时的潮气量也有类似下降，从1099±87降至523±21ml。丙泊酚输注停止30分钟后，这些变量也恢复到输注前的值。
作者得出结论，用于清醒镇静的丙泊酚输注显著降低了斜率，并导致在等碳酸血症期间测量的低氧通气反应曲线向下移动。
