///2019 Abstract Details
2019 Abstract Details2019-07-13T07:45:15-05:00

Clinical Trial of Transnasal Humidified Rapid Insufflation Ventilatory Exchange (THRIVE) pre-oxygenation in Women having Planned Caesarean Delivery.

Abstract Number: T2A-350
Abstract Type: Original Research

Saba Al-Sulttan MBChB MSc FRCA1 ; Ryan Howle MBChB BSc FRCA2; Columb Malachy FRCA FFICM3; Sohail Bampoe BSc MSc MBBS FRCA4; Pervez Sultan MBChB MD(Res) FRCA5

Introduction

THRIVE, Transnasal Humidified Rapid-Insufflation Ventilatory Exchange, is a form of high-flow humidified nasal oxygen delivery system delivers high concentrations of oxygen and may improve pre-oxygenation before the start of general anaesthesia and allows continued apnoeic oxygenation after induction of anaesthesia between apnoea and successful tracheal intubation and ventilation. The aim is to determine the number of vital capacity (VC) breaths required using THRIVE to pre-oxygenate 90% of parturients to an end-tidal oxygen concentration fraction (FETO2) of >0.90 (EN90).

Methods

After ethical approval We used an up-down sequential allocation methodology to investigate the effective number of VC breaths with THRIVE that produces a therapeutic response (i.e. FETO2 of >0.90) in 90% of the parturients (EN90). Each patient was assessed with 3 interventions, THRIVE mouth closed, THRIVE mouth open and with standard facemask pre-oxygenation.

The primary aim of the trial is to determine the number of vital capacity breaths required using THRIVE mouth closed to pre-oxygenate 90% of parturients to a FETO2 of >0.90 (EN90). Secondary outcomes include assessment of THRIVE mouth open, facemask pre-oxygenation, maternal satisfaction and fetal outcomes. The study plans to enroll N=50 parturients.

This preliminary analysis was to simply compare the initial relative performances of the methods of oxygenation in the study. McNemar chi-square tests with exact P values were used to assess the paired responses with P<0.05 as significant.

Results

The results for date for n=9 patients are shown in the Figure. The rates for successful oxygenation were 2, 0 and 6 for THRIVE mouth closed, THRIVE mouth open and facemask respectively. At the numbers of vital capacities tested so far, facemask appears to be significantly (P=0.031) more effective than THRIVE mouth open.

Discussion

Although it is too early to conclude, up to 17 VC breaths were not reliably successful in achieving FETO2 of >0.90 with THRIVE, 4 of 7 of these unsuccessful participants had their ETO2 of 90 achieved via traditional facemask oxygenation. This suggests that the failure to pre-oxygenate can be due to THRIVE rather than the participants at the range of VC breaths tested so far.

Reference

PCF Tan, AT Dennis. High-flow humidified nasal pre-oxygenation in pregnant women. Anaesthesia. 2016; 71: 847-61.



SOAP 2019