Hypoxemia Index Associated with Prehospital Intubation in COVID-19 Patients.

Romain Jouffroy,Benoit Frattini,Daniel Jost,Marine Scannavino,Clement Derkenne,Kilian Bertho,Frederic Lemoine,Romain Kedzierewicz,Bertrand Prunet

doi:10.3390/jcm9093025

Abstract

Background: There exists a need for prognostic tools for the early identification of COVID-19 patients requiring prehospital intubation. Here we investigated the association between a prehospital Hypoxemia Index (HI) and the need for intubation among COVID-19 patients in the prehospital setting. Methods: We retrospectively analyzed COVID-19 patients initially cared for by a Paris Fire Brigade advanced life support (ALS) team in the prehospital setting between 8th March and 18th April of 2020. We assessed the association between HI and prehospital intubation using receiver operating characteristic (ROC) curve analysis and logistic regression model analysis after propensity score matching. Results are expressed as odds ratio (OR) and 95% confidence interval (CI). Results: We analyzed 300 consecutive COVID-19 patients (166 males (55%); mean age, 64 ± 18 years). Among these patients, 45 (15%) were deceased on the scene, 34 (11%) had an active care restriction, and 18 (6%) were intubated in the prehospital setting. The mean HI value was 3.4 ± 1.9. HI was significantly associated with prehospital intubation (OR, 0.24; 95% CI: 0.12–0.41, p < 10−3) with a corresponding area under curve (AUC) of 0.91 (95% CI: 0.85–0.98). HI significantly differed between patients with and without prehospital intubation (1.0 ± 1.0 vs. 3.6 ± 1.8, respectively; p < 10−3). ROC curve analysis defined the optimal HI threshold as 1.3. Bivariate analysis revealed that HI <1.3 was significantly, positively associated with prehospital intubation (OR, 38.38; 95% CI: 11.57–146.54; p < 10−3). Multivariate logistic regression analysis demonstrated that prehospital intubation was significantly associated with HI (adjusted odds ratio (ORa), 0.20; 95% CI: 0.06–0.45; p < 10−3) and HI <3 (ORa, 51.08; 95% CI: 7.83–645.06; p < 10−3). After adjustment for confounders, the ORa between HI <1.3 and prehospital intubation was 3.6 (95% CI: 1.95–5.08; p < 10−3). Conclusion: An HI of <1.3 was associated with a 3-fold increase in prehospital intubation among COVID-19 patients. HI may be a useful tool to facilitate decision-making regarding prehospital intubation of COVID-19 patients initially cared for by a Paris Fire Brigade ALS team. Further prospective studies are needed to confirm these preliminary results.

Highlights

There exists a need for prognostic tools for the early identification of COVID-19 patients requiring prehospital intubation
One peculiarity of respiratory SARS-CoV-2 infection is the presentation of a low respiratory rate (RR) increase despite severe hypoxemia reflected by low pulse oximetry (SpO2) of variable depth depending on the stage of the disease, along with a lack of functional signs and respiratory distress signs [11]
We report the relationship between COVID-19 patients intubated in the prehospital setting by a Paris Fire Brigade advanced life support team and the Hypoxemia Index (HI), defined as the ratio between initial pulse oximetry and initial respiratory rate

Summary

Introduction

There exists a need for prognostic tools for the early identification of COVID-19 patients requiring prehospital intubation. One peculiarity of respiratory SARS-CoV-2 infection is the presentation of a low respiratory rate (RR) increase despite severe hypoxemia reflected by low pulse oximetry (SpO2) of variable depth depending on the stage of the disease, along with a lack of functional signs and respiratory distress signs [11]. This remarkable disconnect in rest between profound hypoxemia and proportional signs of respiratory distress was named “happy hypoxia” by Dhont et al [12]

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Results

Conclusion