Weerasuriya Scott, Vlachos Savvas, Bobo Ahmed, Jayaprabhu Namitha Birur, Matthews Lauren, Blackstock Adam R, Metaxa Victoria
Department of Critical Care Medicine, King's College Hospital NHS Foundation Trust, London, UK.
Acute Crit Care. 2023 Feb;38(1):31-40. doi: 10.4266/acc.2022.01081. Epub 2023 Feb 27.
It can be challenging for clinicians to predict which patients with respiratory failure secondary to coronavirus disease 2019 (COVID-19) will fail on high-flow nasal cannula (HFNC) oxygen and require escalation of therapy. This study set out to evaluate the association between the respiratory rate-oxygenation index (ROX) and HFNC failure in such patients and to assess whether ROX trajectory correlates with treatment failure.
This was a single-centre, retrospective, observational study of patients with COVID-19 requiring HFNC, conducted over a 3-month period. ROX was calculated as "pulse-oximetry oxygen saturation (SpO2) over the fractional inspired oxygen concentration (FiO2)/respiratory rate" for each patient at 2, 4, and 12 hours from starting HFNC. HFNC failure was defined as escalation to continuous positive airway pressure ventilation or invasive mechanical ventilation (IMV). Time-to-event analyses were performed to account for the longitudinal data set and time-dependent variables.
We included 146 patients. Ninety-three (63.7%) experienced HFNC failure, with 53 (36.3%) requiring IMV. Higher ROX values were associated with a lower subhazard of HFNC failure on time-to-HFNC failure analysis (subhazard ratio, 0.29; 95% confidence interval [CI], 0.18-0.46; P<0.001). This remained true after controlling for informative censoring. Median ROX values changed differentially over time, increasing in the HFNC success group (0.06 per hour; 95% CI, 0.05-0.08; P<0.001) but not in the HFNC failure group (0.004 per hour; 95% CI, -0.05 to 0.08; P=0.890).
A higher ROX is associated with a lower risk of HFNC failure. Monitoring ROX trajectory over time may help identify patients at risk of treatment failure. This has potential clinical applications; however, future prospective studies are required.
对于临床医生而言，预测哪些2019冠状病毒病（COVID-19）继发呼吸衰竭的患者在高流量鼻导管（HFNC）吸氧治疗时会失败并需要升级治疗可能具有挑战性。本研究旨在评估此类患者的呼吸频率-氧合指数（ROX）与HFNC治疗失败之间的关联，并评估ROX轨迹是否与治疗失败相关。
这是一项为期3个月的针对需要HFNC治疗的COVID-19患者的单中心回顾性观察研究。从开始HFNC治疗起2小时、4小时和12小时，计算每位患者的ROX，公式为“脉搏血氧饱和度（SpO2）除以吸入氧分数浓度（FiO2）与呼吸频率之比”。HFNC治疗失败定义为升级为持续气道正压通气或有创机械通气（IMV）。进行事件发生时间分析以处理纵向数据集和时间依赖性变量。
我们纳入了146例患者。93例（63.7%）经历了HFNC治疗失败，其中53例（36.3%）需要IMV。在HFNC治疗失败时间分析中，较高的ROX值与较低的HFNC治疗失败亚风险相关（亚风险比，0.29；95%置信区间[CI]，0.18 - 0.46；P < 0.001）。在控制信息删失后，情况依然如此。ROX的中位数随时间变化不同，HFNC治疗成功组上升（每小时0.06；95% CI，0.05 - 0.08；P < 0.001），而HFNC治疗失败组未上升（每小时0.004；95% CI， - 0.05至0.08；P = 0.890）。
较高的ROX与较低的HFNC治疗失败风险相关。随时间监测ROX轨迹可能有助于识别有治疗失败风险的患者。这具有潜在的临床应用价值；然而，还需要未来的前瞻性研究。
