Lung ultrasound response to awake prone positioning predicts the need for intubation in patients with COVID-19 induced acute hypoxemic respiratory failure: an observational study.

BACKGROUND: Awake prone positioning (APP) reduces the intubation rate in COVID-19 patients treated by high-flow nasal cannula (HFNC). However, the lung aeration response to APP has not been addressed. We aimed to explore the lung aeration response to APP by lung ultrasound (LUS). METHODS: This two-center, prospective, observational study enrolled patients with COVID-19-induced acute hypoxemic respiratory failure treated by HFNC and APP. LUS score was recorded 5-10 min before, 1 h after APP, and 5-10 min after supine in the first APP session within the first three days. The primary outcome was LUS score changes in the first three days. Secondary outcomes included changes in SpO2/FiO2 ratio, respiratory rate and ROX index (SpO2/FiO2/respiratory rate) related to APP, and the rate of treatment success (patients who avoided intubation). RESULTS: Seventy-one patients were enrolled. LUS score decreased from 20 (interquartile range [IQR] 19-24) to 19 (18-21) (p < 0.001) after the first APP session, and to 19 (18-21) (p < 0.001) after three days. Compared to patients with treatment failure (n = 20, 28%), LUS score reduction after the first three days in patients with treatment success (n = 51) was greater (- 2.6 [95% confidence intervals - 3.1 to - 2.0] vs 0 [- 1.2 to 1.2], p = 0.001). A decrease in dorsal LUS score > 1 after the first APP session was associated with decreased risk for intubation (Relative risk 0.25 [0.09-0.69]). APP daily duration was correlated with LUS score reduction in patients with treatment success, especially in dorsal lung zones (r = - 0.76; p < 0.001). CONCLUSIONS: In patients with acute hypoxemic respiratory failure due to COVID-19 and treated by HFNC, APP reduced LUS score. The reduction in dorsal LUS scores after APP was associated with treatment success. The longer duration on APP was correlated with greater lung aeration. Trial registration This study was prospectively registered on clinicaltrials.gov on April 22, 2021. Identification number NCT04855162 .

Factors for success of awake prone positioning in patients with COVID-19-induced acute hypoxemic respiratory failure: analysis of a randomized controlled trial.

BACKGROUND: Awake prone positioning (APP) improves oxygenation in coronavirus disease (COVID-19) patients and, when successful, may decrease the risk of intubation. However, factors associated with APP success remain unknown. In this secondary analysis, we aimed to assess whether APP can reduce intubation rate in patients with COVID-19 and to focus on the factors associated with success. METHODS: In this multicenter randomized controlled trial, conducted in three high-acuity units, we randomly assigned patients with COVID-19-induced acute hypoxemic respiratory failure (AHRF) requiring high-flow nasal cannula (HFNC) oxygen to APP or standard care. Primary outcome was intubation rate at 28 days. Multivariate analyses were performed to identify the predictors associated to treatment success (survival without intubation). RESULTS: Among 430 patients randomized, 216 were assigned to APP and 214 to standard care. The APP group had a lower intubation rate (30% vs 43%, relative risk [RR] 0.70; CI95 0.54-0.90, P = 0.006) and shorter hospital length of stay (11 interquartile range [IQR, 9-14] vs 13 [IQR, 10-17] days, P = 0.001). A respiratory rate ≤ 25 bpm at enrollment, an increase in ROX index > 1.25 after first APP session, APP duration > 8 h/day, and a decrease in lung ultrasound score ≥ 2 within the first 3 days were significantly associated with treatment success for APP. CONCLUSION: In patients with COVID-19-induced AHRF treated by HFNC, APP reduced intubation rate and improved treatment success. A longer APP duration is associated with APP success, while the increase in ROX index and decrease in lung ultrasound score after APP can also help identify patients most likely to benefit. TRIAL REGISTRATION: This study was retrospectively registered in ClinicalTrials.gov at July 20, 2021. Identification number NCT04477655. https://clinicaltrials.gov/ct2/show/NCT04477655?term=PRO-CARF&draw=2&rank=1.

Prone positioning in non-intubated patients with COVID-19 associated acute respiratory failure, the PRO-CARF trial: A structured summary of a study protocol for a randomised controlled trial.

OBJECTIVES: To assess the effect of prone positioning therapy on intubation rate in awake patients with COVID-19 and acute respiratory failure. TRIAL DESIGN: This is a two-center parallel group, superiority, randomized (1:1 allocation ratio) controlled trial. PARTICIPANTS: All patients admitted to the Hospital Civil de Guadalajara and Hospital General de Occidente in Mexico for COVID-19 associated acute respiratory failure and in need of supplementary oxygen through high-flow nasal cannula are screened for eligibility. INCLUSION CRITERIA: all adult patients admitted to the COVID-19 unit who test positive for COVID-19 by PCR-test and in need for oxygen are eligible for inclusion. Randomization starts upon identification of requirement of a fraction of inspired oxygen ≥30% for an oxygen capillary saturation of ≥90% Exclusion criteria: less than 18 years-old, pregnancy, patients with immediate need of invasive mechanical ventilation (altered mental status, fatigue), vasopressor requirement to maintain median arterial pressure >65 mmHg, contraindications for prone positioning therapy (recent abdominal or thoracic surgery or trauma, facial, pelvic or spine fracture, untreated pneumothorax, do-not-resuscitate or do-not-intubate order, refusal or inability of the patient to enroll in the study. INTERVENTION AND COMPARATOR: Patients of the intervention group will be asked to remain in a prone position throughout the day as long as possible, with breaks according to tolerance. Pillows will be offered for maximizing comfort at chest, pelvis and knees. Monitoring of vital signs will not be suspended. Inspired fraction of oxygen will be titrated to maintain a capillary saturation of 92%-95%. For patients in the control group, prone positioning will be allowed as a rescue therapy. Staff intensivists will monitor the patient's status in both groups on a 24/7 basis. All other treatment will be unchanged and left to the attending physicians. MAIN OUTCOMES: Endotracheal intubation rate for mechanical ventilation at 28 days. RANDOMISATION: Patients will be randomly allocated to either prone positioning or control group at 1:1 ratio. Such randomization will be computer generated and stratified by center with permuted blocks and length of 4. BLINDING (MASKING): Due to logistical reasons, only principal investigators and the data analyst will be blinded to group assignment. NUMBERS TO BE RANDOMISED (SAMPLE SIZE): With an intubation rate of 60% according to recent reports from some American centers, and assuming a decrease to 40% to be clinically relevant, we calculated a total of 96 patients per group, for a beta error of 0.2, and alpha of 0.5. Therefore, we plan to recruit 200 patients, accounting for minimal losses to follow up, with 100 non-intubated patients in the prone position group and a 100 in the control group. TRIAL STATUS: The local registration number is 048-20, with the protocol version number 2.0. The date of approval is 3rd May 2020. Recruitment started on 3rd May and is expected to end in December 2020. TRIAL REGISTRATION: The protocol was retrospectively registered under the title: "Prone Positioning in Non-intubated Patients With COVID-19 Associated Acute Respiratory Failure. The PRO-CARF trial" in ClinicalTrials.gov with the registration number: NCT04477655. Registered on 20 July 2020. FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol. The study protocol has been reported in accordance with the Standard Protocol Items: Recommendations for Clinical Interventional Trials (SPIRIT) guidelines (Additional file 2).