# Efficacy and adverse effects of three delivery methods for aerosolized salbutamol in anesthetized European moose (Alces alces alces): a case series

## TL;DR

This study tested three ways to give aerosolized salbutamol to anesthetized moose to see if it helps with breathing issues, but found no clear benefit over a placebo.

## Contribution

The study is the first to evaluate aerosolized salbutamol delivery methods in anesthetized European moose for hypoxemia.

## Key findings

- Aerosolized salbutamol was well tolerated but did not significantly improve hypoxemia compared to placebo.
- The largest increase in PaO₂ was observed with salbutamol delivered via an intranasal tube.
- No adverse effects were observed during or after the treatments.

## Abstract

Wild and captive European moose (Alces alces alces) are routinely anesthetized with drug combinations including alpha-2 adrenoceptor agonists, dissociative anesthetics, and opioids. Reportedly, severe respiratory depression, ventilation/perfusion (V/Q) mismatch, and hypoxemia are common complications in this species, requiring perianesthetic oxygen supplementation as key treatment, athough high flow rates can exacerbate respiratory acidosis. Salbutamol is a β2-adrenoceptor agonist effective in alleviating V/Q mismatch and hypoxemia in anesthetized horses when administered via endotracheal tube. Administration of salbutamol could elicit similar effects in anesthetized moose, improving animal welfare and perhaps reducing or replacing the supplemental oxygen requirements.

Three healthy captive moose (two juveniles, male and female, and one adult male) underwent four anesthetic events for routine zoo health assessments. One juvenile was anesthetized again after 15 days and served as its own control. Moose were anesthetized with medetomidine (0.05–0.08 mg kg−1), ketamine (1.7–2.8 mg kg−1), and butorphanol (0.04–0.07 mg kg−1) intramuscularly (IM). Intranasal oxygen (1 L min−1 100 kg−1) was administered, and they were allocated to receive either 10 mL saline (control) or aerosolized salbutamol. Salbutamol was administered incrementally at 200, 400 and 800 µg 100 kg−1, with 10-minute monitoring intervals following each dose, using one of three methods: a spacer, an equine intranasal (IN) tube, or an equine medical mask. Invasive blood pressure, electrocardiogram, respiratory rate, SpO2, and rectal temperature were recorded every 5 min. Arterial blood gases and electrolytes were measured before oxygen supplementation and both before and 10 min after each salbutamol dose. Anesthesia was reversed with IM atipamezole (0.3–0.4 mg kg−1), and all moose were monitored for seven days post-anesthesia for adverse effects. All moose were hypoxemic, hypercapnic, hypertensive, and tachypneic. No hypotension or hypokalemia occurred. PaO₂ increased in all individuals, with no consistent difference between treatment and control. The largest PaO₂ increase occurred in the moose receiving salbutamol via the IN tube. Other physiological variables remained stable. Recoveries were uneventful, with no adverse effects observed.

Aerosolized salbutamol was well tolerated, but did not provide a clear benefit for hypoxemia compared to placebo. Further studies with higher salbutamol doses, alternative delivery routes, or modified anesthetic protocols are recommended.

The online version contains supplementary material available at 10.1186/s13028-026-00856-7.