Abstract：
OBJECTIVE: To study the changes in dynamic compliance (Cdyn), ventilation/perfusion (V˙/ Q˙) mismatch and haemodynamic variables in hypoxaemic anaesthetized horses whose PaO2 increased following salbutamol inhalation.
METHODS: Retrospective, clinical, cohort study.
METHODS: A group of 73 client-owned horses treated with salbutamol when PaO2 <100 mmHg (13.3 kPa) during anaesthesia.
METHODS: Horses were divided into two groups: responders (R), where PaO2 after salbutamol ≥1.2 PaO2 before treatment (i.e. ≥20% increase), and non-responders (NR), where PaO2 after salbutamol <1.2 PaO2 before treatment. Demographic data and intraoperative variables before treatment were compared between R and NR. Cdyn, arterial to end-tidal carbon dioxide difference [P(a-E´)CO2], estimated ratio of dead space to tidal volume (est.VD/VT), estimated shunt fraction (F-shunt), heart rate, systolic, mean and diastolic arterial pressure and dobutamine requirements were compared before and after treatment within R and NR. For each variable, the difference (Δ) between values pre- and posttreatment was calculated and compared between groups R and NR. Numerical data were compared using univariate or bivariate analysis and categorical data were compared using chi-square test; p < 0.05.
RESULTS: Of the 73 horses 50 were classified as R while 23 horses were classified as NR. There was no statistical difference between R and NR for demographic data or initial intraoperative variables except for body weight [R: 531 (170-715) kg, NR: 540 (420-914) kg]. While salbutamol did not alter Cdyn in either group, it significantly decreased P(a-E´)CO2, est.VD/VT and F-shunt in R only. ΔP(a-E´)CO2, Δest.VD/VT and ΔF-shunt were significantly greater in R (-17.8%, -19.0% and -24.1%, respectively) than in NR (11.5%, 6.6% and -0.3%, respectively).
CONCLUSIONS: In hypoxaemic anaesthetized horses responding to inhaled salbutamol by a ≥1.2 increase in PaO2 no change in Cdyn was detected, but indicators of V˙/ Q˙ mismatch improved.
METHODS: Retrospective, clinical, cohort study.
METHODS: A group of 73 client-owned horses treated with salbutamol when PaO2 <100 mmHg (13.3 kPa) during anaesthesia.
METHODS: Horses were divided into two groups: responders (R), where PaO2 after salbutamol ≥1.2 PaO2 before treatment (i.e. ≥20% increase), and non-responders (NR), where PaO2 after salbutamol <1.2 PaO2 before treatment. Demographic data and intraoperative variables before treatment were compared between R and NR. Cdyn, arterial to end-tidal carbon dioxide difference [P(a-E´)CO2], estimated ratio of dead space to tidal volume (est.VD/VT), estimated shunt fraction (F-shunt), heart rate, systolic, mean and diastolic arterial pressure and dobutamine requirements were compared before and after treatment within R and NR. For each variable, the difference (Δ) between values pre- and posttreatment was calculated and compared between groups R and NR. Numerical data were compared using univariate or bivariate analysis and categorical data were compared using chi-square test; p < 0.05.
RESULTS: Of the 73 horses 50 were classified as R while 23 horses were classified as NR. There was no statistical difference between R and NR for demographic data or initial intraoperative variables except for body weight [R: 531 (170-715) kg, NR: 540 (420-914) kg]. While salbutamol did not alter Cdyn in either group, it significantly decreased P(a-E´)CO2, est.VD/VT and F-shunt in R only. ΔP(a-E´)CO2, Δest.VD/VT and ΔF-shunt were significantly greater in R (-17.8%, -19.0% and -24.1%, respectively) than in NR (11.5%, 6.6% and -0.3%, respectively).
CONCLUSIONS: In hypoxaemic anaesthetized horses responding to inhaled salbutamol by a ≥1.2 increase in PaO2 no change in Cdyn was detected, but indicators of V˙/ Q˙ mismatch improved.
摘要：
目的：研究动态依从性（Cdyn）的变化，吸入沙丁胺醇后PaO2增加的低氧血症麻醉马的通气/灌注（V•/Q•）不匹配和血流动力学变量。
方法：回顾性，临床,队列研究。
方法：在麻醉期间，当PaO2<100mmHg（13.3kPa）时，使用沙丁胺醇治疗的73匹客户拥有的马。
方法：将马分为两组：反应者（R），其中沙丁胺醇后的PaO2≥1.2治疗前的PaO2（即≥20％的增加），和非响应者(NR)，其中沙丁胺醇后的PaO2<1.2治疗前的PaO2。比较R和NR治疗前的人口统计学数据和术中变量。Cdyn,动脉与呼气末二氧化碳差[P(a-E')CO2]，估计死区与潮气量之比(估计。VD/VT),估计分流分数(F分流)，心率,收缩压,在R和NR治疗前后比较平均和舒张压和多巴酚丁胺需求。对于每个变量，计算治疗前后值之间的差异（Δ），并比较R组和NR组之间的差异。使用单变量或双变量分析比较数值数据，使用卡方检验比较分类数据；p<0.05。
结果：在73匹马中，有50匹马被归类为R，而有23匹马被归类为NR。除了体重[R：531（170-715）kg，R和NR之间的人口统计学数据或术中初始变量没有统计学差异，NR：540（420-914）kg]。虽然沙丁胺醇在任何一组中都没有改变Cdyn，它显着降低了P（a-E'）CO2。仅R中的VD/VT和F分流。ΔP(a-E')CO2,Δest。VD/VT和ΔF分流在R中显著更大(-17.8%，-19.0%和-24.1%，分别)比NR(11.5%，6.6%和-0.3%，分别)。
结论：在低氧麻醉马中，对吸入沙丁胺醇的PaO2增加≥1.2的反应没有检测到Cdyn的变化，但是V*/Q*不匹配的指标有所改善。
方法：回顾性，临床,队列研究。
方法：在麻醉期间，当PaO2<100mmHg（13.3kPa）时，使用沙丁胺醇治疗的73匹客户拥有的马。
方法：将马分为两组：反应者（R），其中沙丁胺醇后的PaO2≥1.2治疗前的PaO2（即≥20％的增加），和非响应者(NR)，其中沙丁胺醇后的PaO2<1.2治疗前的PaO2。比较R和NR治疗前的人口统计学数据和术中变量。Cdyn,动脉与呼气末二氧化碳差[P(a-E')CO2]，估计死区与潮气量之比(估计。VD/VT),估计分流分数(F分流)，心率,收缩压,在R和NR治疗前后比较平均和舒张压和多巴酚丁胺需求。对于每个变量，计算治疗前后值之间的差异（Δ），并比较R组和NR组之间的差异。使用单变量或双变量分析比较数值数据，使用卡方检验比较分类数据；p<0.05。
结果：在73匹马中，有50匹马被归类为R，而有23匹马被归类为NR。除了体重[R：531（170-715）kg，R和NR之间的人口统计学数据或术中初始变量没有统计学差异，NR：540（420-914）kg]。虽然沙丁胺醇在任何一组中都没有改变Cdyn，它显着降低了P（a-E'）CO2。仅R中的VD/VT和F分流。ΔP(a-E')CO2,Δest。VD/VT和ΔF分流在R中显著更大(-17.8%，-19.0%和-24.1%，分别)比NR(11.5%，6.6%和-0.3%，分别)。
结论：在低氧麻醉马中，对吸入沙丁胺醇的PaO2增加≥1.2的反应没有检测到Cdyn的变化，但是V*/Q*不匹配的指标有所改善。
