Lung Recruitment, Individualized PEEP, and Prone Position Ventilation for COVID-19-Associated Severe ARDS: A Single Center Observational Study

Real-Time Camera Image-Guided Nasoenteric Tube Placement in Prone COVID-19 ICU Patients: A Single-Center Study

Background & Aims: This study aims to assess the application value of the real-time camera image-guided nasoenteric tube placement in critically ill COVID-19 patients undergoing endotracheal intubation and prone position ventilation therapy. Methods: We enrolled 116 COVID-19 patients receiving endotracheal intubation and prone position ventilation therapy in the intensive care unit (ICU). Patients were randomly divided into the real-time camera image-guided nasoenteric tube placement (n = 58) and bedside blind insertion (n = 58) groups. The success rate, placement time, complications, cost, heart rate, respiratory rate, Glasgow Coma Scale (GCS), and Acute Physiology and Chronic Health Evaluation II (APACHE-II) scores were compared between the 2 groups. Results: For ICU patients with COVID-19 undergoing prone position ventilation therapy, the success rate and cost were significantly higher in the real-time camera image-guided group compared to the bedside blind group (P < .05). The placement time and complication incidence were significantly lower in the real-time camera image-guided group (P < .05). The differences in heart rate, respiratory rate, GCS scores, and APACHE-II scores were insignificant (P > .05). Conclusions: The real-time camera image-guided nasoenteric tube placement system had advantages for ICU COVID-19 patients undergoing prone position ventilation therapy, including a high success rate, short placement time, and no impact on patient position during tube placement. Real-time camera image-guided nasoenteric tube placement can be performed in any position, and demonstrates high efficiency, safety, and accuracy.

PEEP-Induced Lung Recruitment Maneuver Combined with Prone Position for ARDS: A Single-Center, Prospective, Randomized Clinical Trial

Background: Prone position (PP) and the positive end-expiratory pressure (PEEP)-induced lung recruitment maneuver (LRM) are both efficient in improving oxygenation and prognosis in patients with ARDS. The synergistic effect of PP combined with PEEP-induced LRM in patients with ARDS remains unclear. We aim to explore the effects of PP combined with PEEP-induced LRM on prognosis in patients with moderate to severe ARDS and the predicting role of lung recruitablity. Methods: Patients with moderate to severe ARDS were consecutively enrolled. The patients were prospectively assigned to either the intervention (PP with PEEP-induced LRM) or control groups (PP). The clinical outcomes, respiratory mechanics, and electric impedance tomography (EIT) monitoring results for the two groups were compared. Lung recruitablity (recruitment-to-inflation ratio: R/I) was measured during the PEEP-induced LRM procedure and was used for predicting the response to LRM. Results: Fifty-eight patients were included in the final analysis, among which 28 patients (48.2%) received PEEP-induced LRM combined with PP. PEEP-induced LRM enhanced the effect of PP by a significant improvement in oxygenation (∆PaO2/FiO2 75.8 mmHg vs. 4.75 mmHg, p < 0.001) and the compliance of respiratory system (∆Crs, 2 mL/cmH2O vs. -1 mL/cmH2O, p = 0.02) among ARDS patients. Based on the EIT measurement, PP combined with PEEP-induced LRM increased the ventilation distribution mainly in the dorsal region (5.0% vs. 2.0%, p = 0.015). The R/I ratio was measured in 28 subjects. The higher R/I ratio was related to greater oxygenation improvement after LRM (Pearson's r = 0.4; p = 0.034). Conclusions: In patients with moderate to severe ARDS, PEEP-induced LRM combined with PP can improve oxygenation and dorsal ventilation distribution. R/I can be useful to predict responses to LRM.

Response to PEEP in COVID-19 ARDS patients with and without extracorporeal membrane oxygenation. A multicenter case–control computed tomography study

Background

PEEP selection in severe COVID-19 patients under extracorporeal membrane oxygenation (ECMO) is challenging as no study has assessed the alveolar recruitability in this setting. The aim of the study was to compare lung recruitability and the impact of PEEP on lung aeration in moderate and severe ARDS patients with or without ECMO, using computed tomography (CT).

Methods

We conducted a two-center prospective observational case–control study in adult COVID-19-related patients who had an indication for CT within 72 h of ARDS onset in non-ECMO patients or within 72  h after ECMO onset. Ninety-nine patients were included, of whom 24 had severe ARDS under ECMO, 59 severe ARDS without ECMO and 16 moderate ARDS.

Results

Non-inflated lung at PEEP 5 cmH₂O was significantly greater in ECMO than in non-ECMO patients. Recruitment induced by increasing PEEP from 5 to 15 cmH₂O was not significantly different between ECMO and non-ECMO patients, while PEEP-induced hyperinflation was significantly lower in the ECMO group and virtually nonexistent. The median [IQR] fraction of recruitable lung mass between PEEP 5 and 15 cmH₂O was 6 [4–10]%. Total superimposed pressure at PEEP 5 cmH₂O was significantly higher in ECMO patients and amounted to 12 [11–13] cmH₂O. The hyperinflation-to-recruitment ratio (i.e., a trade-off index of the adverse effects and benefits of PEEP) was significantly lower in ECMO patients and was lower than one in 23 (96%) ECMO patients, 41 (69%) severe non-ECMO patients and 8 (50%) moderate ARDS patients. Compliance of the aerated lung at PEEP 5 cmH₂O corrected for PEEP-induced recruitment (C_{BABY LUNG}) was significantly lower in ECMO patients than in non-ECMO patients and was linearly related to the logarithm of the hyperinflation-to-recruitment ratio.

Conclusions

Lung recruitability of COVID-19 pneumonia is not significantly different between ECMO and non-ECMO patients, with substantial interindividual variations. The balance between hyperinflation and recruitment induced by PEEP increase from 5 to 15 cmH₂O appears favorable in virtually all ECMO patients, while this PEEP level is required to counteract compressive forces leading to lung collapse. C_{BABY LUNG} is significantly lower in ECMO patients, independently of lung recruitability.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-04076-z.

Prone position in COVID 19-associated acute respiratory failure

PURPOSE OF REVIEW

Prone position has been widely used in the COVID-19 pandemic, with an extension of its use in patients with spontaneous breathing ('awake prone'). We herein propose a review of the current literature on prone position in mechanical ventilation and while spontaneous breathing in patients with COVID-19 pneumonia or COVID-19 ARDS.

RECENT FINDINGS

A literature search retrieved 70 studies separating whether patient was intubated (24 studies) or nonintubated (46 studies). The outcomes analyzed were intubation rate, mortality and respiratory response to prone. In nonintubated patient receiving prone position, the main finding was mortality reduction in ICU and outside ICU setting.

SUMMARY

The final results of the several randomized control trials completed or ongoing are needed to confirm the trend of these results. In intubated patients, observational studies showed that responders to prone in terms of oxygenation had a better survival than nonresponders.

Effect of prone positioning on oxygenation and static respiratory system compliance in COVID-19 ARDS vs. non-COVID ARDS

Background

Prone positioning is recommended for patients with moderate-to-severe acute respiratory distress syndrome (ARDS) receiving mechanical ventilation. While the debate continues as to whether COVID-19 ARDS is clinically different from non-COVID ARDS, there is little data on whether the physiological effects of prone positioning differ between the two conditions. We aimed to compare the physiological effect of prone positioning between patients with COVID-19 ARDS and those with non-COVID ARDS.

Methods

We retrospectively compared 23 patients with COVID-19 ARDS and 145 patients with non-COVID ARDS treated using prone positioning while on mechanical ventilation. Changes in PaO₂/FiO₂ ratio and static respiratory system compliance (Crs) after the first session of prone positioning were compared between the two groups: first, using all patients with non-COVID ARDS, and second, using subgroups of patients with non-COVID ARDS matched 1:1 with patients with COVID-19 ARDS for baseline PaO₂/FiO₂ ratio and static Crs. We also evaluated whether the response to the first prone positioning session was associated with the clinical outcome.

Results

When compared with the entire group of patients with non-COVID ARDS, patients with COVID-19 ARDS showed more pronounced improvement in PaO₂/FiO₂ ratio [adjusted difference 39.3 (95% CI 5.2–73.5) mmHg] and static Crs [adjusted difference 3.4 (95% CI 1.1–5.6) mL/cmH₂O]. However, these between-group differences were not significant when the matched samples (either PaO₂/FiO₂-matched or compliance-matched) were analyzed. Patients who successfully discontinued mechanical ventilation showed more remarkable improvement in PaO₂/FiO₂ ratio [median 112 (IQR 85–144) vs. 35 (IQR 6–52) mmHg, P = 0.003] and static compliance [median 5.7 (IQR 3.3–7.7) vs. − 1.0 (IQR − 3.7–3.0) mL/cmH₂O, P = 0.006] after prone positioning compared with patients who did not. The association between oxygenation and Crs responses to prone positioning and clinical outcome was also evident in the adjusted competing risk regression.

Conclusions

In patients with COVID-19 ARDS, prone positioning was as effective in improving respiratory physiology as in patients with non-COVID ARDS. Thus, it should be actively considered as a therapeutic option. The physiological response to the first session of prone positioning was predictive of the clinical outcome of patients with COVID-19 ARDS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01819-4.

Effect of prone versus supine position in COVID-19 patients: A systematic review and meta-analysis

Study objective

To review the effects of prone position and supine position on oxygenation parameters in patients with Coronavirus Disease 2019 (COVID-19).

Design

Systematic review and meta-analysis of non-randomized trials.

Patients

Databases of EMBASE, MEDLINE and CENTRAL were systematically searched from its inception until March 2021.

Interventions

COVID-19 patients being positioned in the prone position either whilst awake or mechanically ventilated.

Measurements

Primary outcomes were oxygenation parameters (PaO₂/FiO₂ ratio, PaCO₂, SpO₂). Secondary outcomes included the rate of intubation and mortality rate.

Results

Thirty-five studies (n = 1712 patients) were included in this review. In comparison to the supine group, prone position significantly improved the PaO₂/FiO₂ ratio (study = 13, patients = 1002, Mean difference, MD 52.15, 95% CI 37.08 to 67.22; p < 0.00001) and SpO₂ (study = 11, patients = 998, MD 4.17, 95% CI 2.53 to 5.81; p ≤0.00001). Patients received prone position were associated with lower incidence of mortality (study = 5, patients = 688, Odd ratio, OR 0.44, 95% CI 0.24 to 0.80; p = 0.007). No significant difference was noted in the incidence of intubation rate (study = 5, patients = 626, OR 1.20, 95% CI 0.77 to 1.86; p = 0.42) between the supine and prone groups.

Conclusion

Our meta-analysis demonstrated that prone position improved PaO₂/FiO₂ ratio with better SpO₂ than supine position in COVID-19 patients. Given the limited number of studies with small sample size and substantial heterogeneity of measured outcomes, further studies are warranted to standardize the regime of prone position to improve the certainty of evidence.

PROSPERO Registration: CRD42021234050