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Clinical implementation of Pulsed inhaled Nitric Oxide in equine anaesthesia

Wiklund, Maja


Hypoxaemia is a common complication during horse anaesthesia that is a challenge
to treat. The primary cause of hypoxaemia is the development of a large intrapulmonary
shunt that leads to significant ventilation-perfusion mismatch. Opening
and ventilating atelectasis during anaesthesia requires high airway pressures and
repeated manoeuvres. Another approach to improve gas exchange in the lung is to
redistribute blood flow from atelectatic to well-ventilated lung regions. In
experimental studies, it has been shown possible to target the vasodilating gas nitric
oxide to open ventilated lung parts by pulsing the gas at the beginning of inspiration.

In the first experimental study of the present thesis, the effect of Pulsed inhaled Nitric
Oxide (PiNO) was evaluated during different modes of ventilation in combination
with normal or low cardiac output and blood pressure. In the following clinical
studies, PiNO was evaluated in colic horses undergoing abdominal surgery and in
healthy horses undergoing arthroscopy. In the last study, it was investigated if PiNOinduced
improved arterial oxygenation had an impact on the quality of recovery after
anaesthesia compared to controls. The results showed that PiNO was effective
during mechanical ventilation only if cardiac output blood pressure were adequate,
while PiNO was effective under both hypotensive and normotensive conditions
during spontaneous breathing. In the clinical studies, PiNO effectively improved
arterial oxygenation in both healthy and colic horses, ventilated spontaneously or
mechanically. In the last study, horses that received PiNO during anaesthesia had
better recovery quality compared to controls. In addition, a positive correlation
between arterial oxygenation during anaesthesia and recovery quality was seen.

In summary, PiNO offers a simple and effective option to treat hypoxaemia in
anaesthetised horses. In the future, the effect of oxygenation on the quality of
recovery needs to be further investigated as well as the long-term effects, such as
wound healing in the postoperative period.


horse; anaesthesia; hypoxaemia; nitric oxide; recovery; ventilation

Publicerad i

Acta Universitatis Agriculturae Sueciae
2023, nummer: 2023:11ISBN: 978-91-8046-074-3, eISBN: 978-91-8046-075-0
Utgivare: Swedish University of Agricultural Sciences

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