SponTaneous Respiration using IntraVEnous anaesthesia and Hi-flow nasal oxygen (STRIVE Hi) maintains oxygenation and airway patency during management of the obstructed airway: an observational study

Abstract

Background: High-flow nasal oxygen (HFNO) has been shown to benefit oxygenation, ventilation and upper airway patency in a range of clinical scenarios, however its use in spontaneously breathing patients during general anaesthesia has not been described. Spontaneous respiration using i.v. anaesthesia is the primary technique used at our institution for tubeless airway surgery. We hypothesized that the addition of HFNO would increase our margin of safety, particularly during management of an obstructed airway.

Methods: A retrospective observational study was conducted using a SponTaneous Respiration using IntraVEnous anaesthesia and High-flow nasal oxygen (STRIVE Hi) technique to manage 30 adult patients undergoing elective laryngotracheal surgery.

Results: Twenty-six patients (87%) presented with significant airway and/or respiratory compromise (16 were stridulous, 10 were dyspnoeic). No episodes of apnoea or complete airway obstruction occurred during the induction of anaesthesia using STRIVE Hi. The median [IQR (range)] lowest oxygen saturation during the induction period was 100 [99–100 (97–100)] %. The median [IQR (range)] overall duration of spontaneous ventilation was 44 [40–49.5 (18–100)] min. The median [IQR (range)] end-tidal carbon dioxide (ETCO2) level at the end of the spontaneous ventilation period was 6.8 [6.4–7.1 (4.8–8.9)] kPa. The mean rate of increase in ETCO2 was 0.03 kPa min−1.

Conclusions: STRIVE Hi succeeded in preserving adequate oxygen saturation, end-tidal carbon dioxide and airway patency. We suggest that the upper and lower airway benefits attributed to HFNO, are ideally suited to a spontaneous respiration induction, increasing its margin of safety. STRIVE Hi is a modern alternative to the traditional inhalation induction.

© The Author 2017. Published by Oxford University Press on behalf of the British Journal of Anaesthesia.

Figures

Fig 1

Endoscopic appearance of 3 mm diameter subglottic stenosis in a patient anaesthetized with STRIVE Hi.

Fig 2

The relationship between the duration of spontaneous respiration during the induction phase and oxygen saturation levels (n = 30).

Fig 3

A comparison of oxygen saturations throughout the different phases of spontaneous ventilation showing the effect of varying the inspired oxygen concentration (FiO2) during the maintenance phase. Box plot shows median and first and third quartiles. Vertical extensions indicate minimum and maximum observed measurements.

Fig 4

The relationship between the overall duration of spontaneous respiration and end-tidal (and in five patients arterial, as indicated by the blue circles) carbon dioxide (n = 29). The line represents linear regression with r = 0.091.

Fig 5

Carbon dioxide levels measured at baseline and at the end of the spontaneous ventilation period. Black lines indicate end-tidal measurements (n = 12). Blue lines indicate serial arterial blood gas measurements (n = 5). The red line indicates the mean overall (end-tidal + arterial) rate of increase of carbon dioxide (0.03 kPa.min−1).