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Effects of pulsed inhaled nitric oxide on arterial oxygenation during mechanical ventilation in anaesthetised horses undergoing elective arthroscopy or emergency colic surgery
Author(s) -
Wiklund M.,
Kellgren M.,
Wulcan S.,
Grubb T.,
Nyman G.
Publication year - 2020
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/evj.13129
Subject(s) - medicine , anesthesia , nitric oxide , oxygenation , mechanical ventilation , surgery
Summary Background Administration of pulsed inhaled nitric oxide (Pi NO ) improves arterial oxygenation in spontaneously breathing anaesthetised healthy horses and in horses undergoing colic surgery. However, because hypoventilation commonly occurs, horses are often mechanically ventilated to prevent hypercarbia. Objectives To evaluate the effects of Pi NO on arterial oxygenation during anaesthesia in mechanically ventilated healthy horses and horses undergoing colic surgery. Study design Prospective nonblinded clinical trial. Methods Fifty horses undergoing elective arthroscopy (Group A) and 30 horses undergoing colic surgery (Group C) in dorsal recumbency were included in the study. Every second horse in each group received Pi NO (A‐ INO , C‐ INO ), the others served as controls (A‐ CN , C‐ CN ). All horses were mechanically ventilated and anaesthesia was maintained with isoflurane. Pi NO was mechanically delivered at the proximal end of the endotracheal tube as a pulse during the first part of each inspiration. Data were collected at the start (baseline, before Pi NO ) and at the end of inhalation anaesthesia. The Tukey method was used to compare baseline and end values for each parameter. Results Arterial oxygen tension (PaO 2 ) increased from (median [ IQR ]) 13.6 (9.3, 30.1) at baseline to 24.2 (18.6, 37.0) kP a at the end of anaesthesia in A‐ INO (P = 0.005) and from 7.7 (6.4, 8.5) to 15.5 (9.9, 26.9) kP a in C‐ INO (P = 0.007). Mean (95% CI ) difference in F‐shunt between baseline and end were −6 (−10; −1) and −11 (−22; −1) % in A‐ INO (P = 0.005) and C‐ INO (P = 0.04) respectively. There was no change in PaO 2 or F‐shunt from baseline to end of anaesthesia in A‐ CN or C‐CN. Main limitations Cardiac output was not measured, thus O 2 delivery could not be calculated. Conclusions The combination of mechanical ventilation and Pi NO improved pulmonary gas exchange during anaesthesia by a simultaneous decrease in F‐shunt and improved alveolar ventilation.