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High‐flow nasal oxygen vs. standard flow‐rate facemask pre‐oxygenation in pregnant patients: a randomised physiological study
Author(s) -
Shippam W.,
Preston R.,
Douglas J.,
Taylor J.,
Albert A.,
Chau A.
Publication year - 2019
Publication title -
anaesthesia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.839
H-Index - 117
eISSN - 1365-2044
pISSN - 0003-2409
DOI - 10.1111/anae.14567
Subject(s) - medicine , anesthesia , oxygenation , tidal volume , breathing , respiratory rate , oxygen , work of breathing , respiratory system , heart rate , mechanical ventilation , blood pressure , chemistry , organic chemistry
Summary High‐flow nasal oxygen has been shown to provide effective pre‐oxygenation and prolong apnoeic time during intubation attempts in non‐pregnant patients. We aimed to compare pre‐oxygenation using high‐flow nasal oxygen (30–70 l.min −1 oxygen flow) via nasal prongs with standard 15 l.min −1 oxygen breathing via a tight‐fitting facemask. Forty healthy parturients were randomly allocated to these two groups, and furthermore each patient underwent the selected pre‐oxygenation method with both 3‐min tidal volume breathing and 30s tidal breathing followed by eight vital capacity breaths. With 3‐min tidal volume breathing, the respective estimated marginal means for high‐flow nasal oxygen and standard flow rate facemask pre‐oxygenation were 87.4% (95% CI 85.5–89.2%) and 91.0% (95% CI 89.3–92.7%), p = 0.02; with eight vital capacity breaths the estimated marginal means were 85.9% (95% CI 84.1–87.7%) and 91.8% (95% CI 90.1–93.4%, p < 0.0001). Furthermore, high‐flow nasal oxygen did not reliably achieve a mean end‐tidal oxygen concentration ≥ 90% compared with the standard flow rate facemask. In this physiological study, high‐flow nasal oxygen pre‐oxygenation performed worse than standard flow rate facemask pre‐oxygenation in healthy term parturients.