Effects of high-flow oxygen therapy on oxygenation in dogs undergoing diagnostic bronchoscopy

Abstract

Introduction: Hypoxemia is a common complication during bronchoscopy and bronchoalveolar lavage (BAL). High-Flow Oxygen Therapy (HFOT) has been used to improve oxygenation and prevent periods of hypoxemia in people undergoing bronchoscopy.

Objective: The main objective of this study was to evaluate the effect of HFOT on oxygenation in dogs undergoing diagnostic bronchoscopy compared to a traditional oxygen supplementation method (TOT). A secondary objective was to assess potential HFOT-related complications.

Methods: Prospective randomized clinical trial. Dogs presented for diagnostic bronchoscopy were randomly assigned to receive either HFOT or TOT using nasal cannulas during the bronchoscopic procedure. Oxygenation was monitored through PaO₂ measurements taken at seven time points: baseline (t0), after preoxygenation (t1), post-induction (t2), pre- and post-BAL sampling (t3 and t4), at the end of the procedure (t5), and 1 h after bronchoscopy (t6). Pre- and post-procedure thoracic radiographs were assessed for air leak syndrome or aerophagia.

Results: 20 privately owned dogs presented for diagnostic bronchoscopy were included in the study (HFOT group: n = 10, TOT group: n = 10). Baseline characteristics and physiological parameters did not differ significantly between groups. Five dogs in each group showed hypoxemia (PaO₂ < 80 mmHg) at baseline with 1/5 in each group having PaO₂ < 60 mmHg. HFOT improved oxygenation throughout the procedure, with a significant increase in PaO₂ observed after preoxygenation (P = 0.001) and at the end of the procedure (P = 0.013). Additionally, only 1/10 dogs in the HFOT group experienced hypoxemia during bronchoscopy compared to 5/10 dogs in the TOT group, and patients in the HFOT achieved numerically higher PaO₂ values across all time points during the procedure (t1-t5). No serious adverse events related to HFOT were observed, although aerophagia occurred in both groups without necessitating intervention.

Conclusion: HFOT can improve oxygenation and prevent episodes of hypoxemia in dogs undergoing bronchoscopy compared to traditional oxygen supplementation methods.

Keywords: bronchoscopy; dogs; high flow oxygen therapy; hypoxemia; oxygen supplementation; oxygenation.

Figure 1

Picture depicting patient placement and setup for bronchoscopy.

Figure 2

Timeline depicting the bronchoscopic procedure and the individual time points for arterial blood gas sampling.

Figure 3

Differences in PaO₂ at different time points between the TOT and the HFOT group. (A) Differences in PaO₂ at baseline (t0); p = 0.664. (B) Differences in PaO₂ after preoxygenation (t1); p = 0.001. (C) Differences in PaO₂ after induction of anesthesia (t2); p = 0.304. (D) Differences in PaO₂ before BAL (t3); p = 0.102. (E) Difference in PaO₂ after bronchoalveolar lavage (t4). p = 0.056. (F) Difference in PaO₂ at the end of the procedure (t5); p = 0.013. PaO₂, partial pressure of arterial oxygen; TOT, traditional oxygen therapy; HFOT, High-Flow Oxygen Therapy. ^*P ≤ 0.05; ^***P ≤ 0.001; ns > 0.05.

Figure 4

Linear graph showing mean and standard error of mean from baseline (t0) across all time points during the procedure (t1–t5) for each group, TOT, traditional oxygen therapy; HFOT, High-Flow Oxygen Therapy.

Figure 5

Difference in P_aCO₂ values (mean and standard deviation) between TOT and HFOT groups across time points t0–t6, TOT, traditional oxygen therapy; HFOT, High-Flow Oxygen Therapy.

Figure 6

Frequency and distribution of aerophagia compared between the TOT and HFOT groups. TOT, traditional oxygen therapy; HFOT, High-Flow Oxygen Therapy.