Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA.
Department of Veterinary Sciences, University of Pisa, Pisa, Italy.
Vet Anaesth Analg. 2023 Jul;50(4):363-371. doi: 10.1016/j.vaa.2023.03.002. Epub 2023 Mar 22.
To evaluate the impact of a 30% end-inspiratory pause (EIP) on alveolar tidal volume (V), airway (V) and physiological (V) dead spaces in mechanically ventilated horses using volumetric capnography, and to evaluate the effect of EIP on carbon dioxide (CO) elimination per breath (Vcobr), PaCO and the ratio of PaO-to-fractional inspired oxygen (PaO:FiO).
Prospective research study.
A group of eight healthy research horses undergoing laparotomy.
Anesthetized horses were mechanically ventilated as follows: 6 breaths minute, tidal volume (V) 13 mL kg, inspiratory-to-expiratory time ratio 1:2, positive end-expiratory pressure 5 cmHO and EIP 0%. Vcobr and expired tidal volume (V) of 10 consecutive breaths were recorded 30 minutes after induction, after adding 30% EIP and upon EIP removal to construct volumetric capnograms. A stabilization period of 15 minutes was allowed between phases. Data were analyzed using a mixed-effect linear model. Significance was set at p < 0.05.
The EIP decreased V from 6.6 (6.1-6.7) to 5.5 (5.3-6.1) mL kg (p < 0.001) and increased V from 7.7 ± 0.7 to 8.6 ± 0.6 mL kg (p = 0.002) without changing the V. The V to V ratio decreased from 51.0% to 45.5% (p < 0.001) with EIP. The EIP also increased PaO:FiO from 393.3 ± 160.7 to 450.5 ± 182.5 mmHg (52.5 ± 21.4 to 60.0 ± 24.3 kPa; p < 0.001) and Vcobr from 0.49 (0.45-0.50) to 0.59 (0.45-0.61) mL kg (p = 0.008) without reducing PaCO.
The EIP improved oxygenation and reduced V and V, without reductions in PaCO. Future studies should evaluate the impact of different EIP in healthy and pathological equine populations under anesthesia.
使用容量测定碳酸图评估 30%吸气末停顿（EIP）对机械通气马的肺泡潮气量（V）、气道（V）和生理（V）死腔的影响，并评估 EIP 对每呼吸二氧化碳消除量（Vcobr）、PaCO 和动脉血氧分压与吸入氧分数比值（PaO:FiO）的影响。
前瞻性研究。
一组 8 头接受剖腹手术的健康研究马。
麻醉马以以下方式进行机械通气：6 次/分钟，潮气量（V）13mL/kg，吸气至呼气时间比 1:2，呼气末正压 5cmH2O，EIP 为 0%。在诱导后 30 分钟、添加 30%EIP 后以及 EIP 去除后，连续记录 10 次呼吸的 Vcobr 和呼出潮气量（V），以构建容量测定碳酸图。各阶段之间允许 15 分钟的稳定期。使用混合效应线性模型分析数据。设 p < 0.05 为有统计学意义。
EIP 使 V 从 6.6（6.1-6.7）降至 5.5（5.3-6.1）mL/kg（p < 0.001），V 从 7.7±0.7 增至 8.6±0.6mL/kg（p=0.002），但 V 不变。V 与 V 的比值从 51.0%降至 45.5%（p < 0.001）。EIP 还使 PaO:FiO 从 393.3±160.7 增至 450.5±182.5mmHg（52.5±21.4 至 60.0±24.3kPa；p < 0.001），Vcobr 从 0.49（0.45-0.50）增至 0.59（0.45-0.61）mL/kg（p=0.008），而 PaCO 无降低。
EIP 改善了氧合作用，降低了 V 和 V，而不降低 PaCO。未来的研究应评估不同 EIP 在麻醉健康和病理马群中的影响。
