Desaturation times between dogs preoxygenated via face mask or flow-by technique before induction of anesthesia

Barbara Ambros; Maria Valentina Carrozzo; Teela Jones

doi:10.1016/j.vaa.2018.03.004

Desaturation times between dogs preoxygenated via face mask or flow-by technique before induction of anesthesia

Vet Anaesth Analg. 2018 Jul;45(4):452-458. doi: 10.1016/j.vaa.2018.03.004. Epub 2018 Apr 10.

Authors

Barbara Ambros¹, Maria Valentina Carrozzo², Teela Jones²

Affiliations

¹ Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada. Electronic address: barbara.ambros@usask.ca.
² Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada.

PMID: 29739649
DOI: 10.1016/j.vaa.2018.03.004

Abstract

Objective: To compare time to desaturation after induction of anesthesia following administration of oxygen via face mask or flow-by for 3 minutes.

Study design: Randomized crossover study.

Animals: A group of six healthy adult dogs weighing 15.0 ± 3.4 kg.

Methods: Dogs were anesthetized twice separated by 14 days. Intramuscular administration of dexmedetomidine (4 μg kg^-1), acepromazine (0.01 mg kg^-1) and butorphanol (0.2 mg kg^-1) provided sedation for percutaneous insertion of a catheter into the tracheal lumen. The tip was advanced to the thoracic inlet and position confirmed using fluoroscopy. Using a sample aspiration rate 200 mL minute^-1, inspired (FIO₂) and end-tidal oxygen (Fe'O₂) were measured. Oxygen (100 mL kg^-1 minute^-1) was delivered into a circle delivery system and administered to the dog for 3 minutes via face mask or flow-by from the circle Y-piece 2.5 cm from the nares. Then, propofol was administered to induce anesthesia and apnea. A pulse oximeter (lingual probe) measured hemoglobin saturation (SpO₂). At SpO₂ 90% (desaturation point), an endotracheal tube was inserted to allow administration of oxygen and artificial ventilation. Arterial blood and data were collected at baseline (before oxygen administration), 5 seconds after induction of anesthesia, and every 30 seconds until the desaturation point was reached. Data were analyzed using an unpaired and paired t test with (p < 0.05).

Results: FIO₂, Fe'O₂ and PaO₂ (mean ± standard deviation) were significantly higher after mask preoxygenation [89.7 ± 5.5%, 83.0 ± 7.6% and 394 ± 112 mmHg (52.4 ± 14.9 kPa)] compared with flow-by [30.0 ± 5.4%, 22.7 ± 3.8% and 133 ± 22 mmHg (17.7 ± 2.9 kPa)], respectively. Time to desaturation was significantly longer after mask treatment compared with flow-by (187 ± 67 versus 66 ± 17 seconds).

Conclusions and clinical relevance: Mask preoxygenation provided longer time to desaturation compared with the flow-by technique tested.

Keywords: anesthetic induction; dog; face mask; flow-by; preoxygenation.

Publication types

Randomized Controlled Trial

MeSH terms

Anesthesia, General / methods
Anesthesia, General / veterinary*
Animals
Cross-Over Studies
Dogs
Female
Laryngeal Masks / veterinary
Male
Oximetry / veterinary
Oxygen / administration & dosage*
Oxygen / blood
Respiratory Rate

Substances

Oxygen