Grubb Tamara, Frendin Jan H M, Edner Anna, Funkquist Pia, Hedenstierna Göran, Nyman Görel
Department of Animal Environment and Health, Faculty of Veterinary Medicine and Animal Husbandry, Swedish University of Agricultural Sciences, Skara, Sweden; Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA.
Vet Anaesth Analg. 2013 Nov;40(6):e19-30. doi: 10.1111/vaa.12037. Epub 2013 Apr 20.
Anaesthetized horses commonly become hypoxaemic due to ventilation/perfusion (V·A/Q·) mismatch and increased pulmonary shunt fraction (Qs·/Qt·). Pulse-delivered inhaled nitric oxide may improve oxygenation but may increase plasma concentration of the potent vasoconstrictor, endothelin-1 (ET-1). Objectives: Study 1) compare arterial oxygen concentration (PaO2) and saturation (SaO2), calculated Qs·/Qt· and ET-1 concentration; and Study 2) assess V·A/Q· matching and measured Qs·/Qt· in isoflurane-anaesthetized horses in left lateral recumbency receiving pulse-delivered inhaled nitric oxide (PiNO group) or inhalant gas only (C group).
Prospective research trial.
Ten Healthy adult Standardbred horses. Two horses were anaesthestized in both groups in a random cross-over design with >4 weeks between studies.
Study 1) Cardiopulmonary data including PaO2, SaO2, Qs·/Qt· and ET-1 concentration were measured or calculated prior to and at various points during PiNO administration in 6PiNO and 6C horses. Two-way repeated measures anova with Bonferroni significant difference test was used for data analysis with p < 0.05 considered significant. Study 2) V·A/Q· matching and Qs·/Qt· were determined using the multiple inert gas elimination technique in 3 horses. Data were collected after 60 minutes of anaesthesia without PiNO (baseline) and 15 minutes after PiNO was pulsed during the first 30%, and then the first 60%, of inspiration. Data were descriptive only.
Study 1) PaO2 and SaO2 were higher and calculated Qs·/Qt· was lower in the PiNO group than the C group at most time points. ET-1 was not different over time or between groups. Study 2) V·A/Q· matching and measured Qs·/Qt· were improved from baseline in all horses but PiNO60% provided no improvement when compared to PiNO30%.
PiNO delivered in the initial portion of the inspiration effectively relieves hypoxaemia in anaesthetized horses by improving V·A/Q· matching and decreasing Qs·/Qt· without affecting ET-1.
麻醉马匹常因通气/灌注（V·A/Q·）不匹配和肺分流分数（Qs·/Qt·）增加而出现低氧血症。脉冲式吸入一氧化氮可能改善氧合，但可能会增加强效血管收缩剂内皮素-1（ET-1）的血浆浓度。目的：研究1）比较动脉血氧浓度（PaO2）和饱和度（SaO2）、计算的Qs·/Qt·和ET-1浓度；研究2）评估左侧卧、接受脉冲式吸入一氧化氮（PiNO组）或仅吸入气体（C组）的异氟烷麻醉马匹的V·A/Q·匹配情况及测量的Qs·/Qt·。
前瞻性研究试验。
10匹健康成年标准赛马。两组各有2匹马采用随机交叉设计进行麻醉，两次研究间隔>4周。
研究1）在6匹PiNO组和6匹C组马匹吸入PiNO之前及给药过程中的不同时间点测量或计算包括PaO2、SaO2、Qs·/Qt·和ET-1浓度在内的心肺数据。采用双向重复测量方差分析及Bonferroni显著性差异检验进行数据分析，p<0.05认为具有显著性。研究2）使用多惰性气体排除技术测定3匹马的V·A/Q·匹配情况及Qs·/Qt·。在无PiNO麻醉60分钟后（基线）以及在吸气的前30%和前60%期间脉冲式给予PiNO后15分钟收集数据。数据仅作描述性分析。
研究1）在大多数时间点，PiNO组的PaO2和SaO2较高，计算的Qs·/Qt·较低。ET-1在不同时间或组间无差异。研究2）所有马匹的V·A/Q·匹配情况及测量的Qs·/Qt·较基线均有改善，但与PiNO30%相比，PiNO60%未显示出进一步改善。
在吸气初始阶段给予PiNO可通过改善V·A/Q·匹配和降低Qs·/Qt·有效缓解麻醉马匹的低氧血症，且不影响ET-1。
