Blumenthal S R, Skoula C M, Gordon B E
Department of Comparative Medicine, Carolinas Medical Center, Charlotte, North Carolina, USA.
Lab Anim Sci. 1998 Feb;48(1):69-73.
Hounds undergoing prolonged or complicated surgical procedures are often underventilated, as indicated by blood gas and end-tidal CO2 (CO2) values when using published ventilatory guidelines. We investigated the relationship between body weight, tidal volume, and inspiratory pressure delivered by the ventilator (lung inflation pressure) in 59 anesthetized hounds (19 to 33 kg). Animals were ventilated under positive pressure control and noninvasively instrumented to monitor blood pressure, ECG, oxygen saturation, CO2, and tidal volume. Weight, sex, and thorax measurements were recorded. All dogs were monitored at lung inflation pressures of 10, 14, and 18 cm H2O, with measurements recorded once CO2 stabilized. Veterinary guidelines recommend tidal volumes of 10 to 15 ml/kg of body weight and lung inflation pressures of 15 to 25 cm H2O. When inflation pressure was below guidelines (10), tidal volume was "normal" (10 to 15 ml/kg), but the animals were underventilated. When inflation pressure was "normal" (14 or 18 cm H2O), tidal volume was above guidelines. Physiologic variables were normal only when inflation pressure was 14 cm H2O. Weight and thorax depth accounted for 32 and 6%, respectively, of tidal volume variability, and tidal volume varied by +/- 250 ml at any given body weight and inflation pressure. None of the measured physical variables accurately predicted tidal volume. These data suggest that the inconsistency in tidal volume is due to a previously undescribed variability in respiratory compliance in the anesthetized hound and that the guidelines for ventilation during surgery need further investigation.
根据已发表的通气指南，接受长时间或复杂外科手术的猎犬往往通气不足，这可通过血气和呼气末二氧化碳（CO2）值来表明。我们调查了59只麻醉后的猎犬（体重19至33千克）的体重、潮气量与呼吸机输送的吸气压力（肺膨胀压力）之间的关系。动物在正压控制下通气，并通过非侵入性仪器监测血压、心电图、血氧饱和度、CO2和潮气量。记录体重、性别和胸部测量数据。所有犬只在肺膨胀压力为10、14和18厘米水柱时进行监测，CO2稳定后记录测量值。兽医指南建议潮气量为10至15毫升/千克体重，肺膨胀压力为15至25厘米水柱。当膨胀压力低于指南值（10）时，潮气量“正常”（10至15毫升/千克），但动物通气不足。当膨胀压力“正常”（14或18厘米水柱）时，潮气量高于指南值。只有当膨胀压力为14厘米水柱时，生理变量才正常。体重和胸深分别占潮气量变异性的32%和6%，在任何给定体重和膨胀压力下，潮气量变化±250毫升。所测量的物理变量均无法准确预测潮气量。这些数据表明，潮气量的不一致是由于麻醉后的猎犬呼吸顺应性存在先前未描述的变异性，并且手术期间的通气指南需要进一步研究。
