Ventilator Management Guided by Driving Pressure: A Better Way to Protect the Lungs?

Supportive Care in Patients with Critical Coronavirus Disease 2019

Specific therapies for the treatment of coronavirus disease 2019 (COVID-19) have limited efficacy in the event a patient worsens clinically and requires admission to the intensive care unit (ICU). Thus, providing quality supportive care is essential to the overall management of patients with critical COVID-19. Patients with respiratory failure not requiring intubation should be supported with noninvasive positive pressure ventilation, continuous positive airway pressure, or high flow oxygenation. Use of these respiratory modalities may prevent patients from subsequently requiring intubation. Basic components of supportive care for the critically ill should be applied equally to patients with COVID-19 in the ICU.

Prognostic factors and outcomes in COVID-19 patients requiring prolonged mechanical ventilation: a retrospective cohort study

Background:

Mechanical ventilation (MV) in coronavirus disease 2019 (COVID-19) patients is associated with high mortality and extensive resource utilization. The aim of this study was to investigate prognostic factors and outcomes associated with prolonged mechanical ventilation (PMV) in COVID-19 patients.

Methods:

This was a retrospective cohort study of COVID-19 patients requiring invasive MV who were hospitalized between 1 March 2020 and 30 June 2021 in the intensive care units (ICUs) of three referral hospitals belonging to a single health system. Data were extracted from electronic health records. PMV was defined as  > 17 days of MV.

Results:

Of 355 patients studied, 86 (24%) required PMV. PMV patients had lower PaO2/FiO2 ratio, higher PCO2, and higher plateau and driving pressures during the first 2 weeks of MV than their short MV (SMV; ⩽ 17 days) counterparts. PMV patients received more proning, neuromuscular blockade, and tracheostomy, had longer ICU and hospital length of stay (LOS), and required discharge to an inpatient rehabilitation facility more frequently (all p < 0.001). Overall 30-day mortality was 43.9%, with no statistically significant difference between PMV and SMV groups. In PMV patients, smoking, Charlson comorbidity index > 6, and week 2 PaO2/FiO2 ratio < 150 and plateau pressure ⩾ 30 were positively associated with 30-day mortality. In a multivariate model, results were directionally consistent with the univariate analysis but did not reach statistical significance.

Conclusion:

PMV is commonly required in COVID-19 patients with respiratory failure. Despite the higher need for critical care interventions and LOS, more than half of the PMV cohort survived to hospital discharge. Higher PaO2/FiO2 ratio, lower plateau pressure, and fewer comorbidities appear to be associated with survival in this group.

Product of driving pressure and respiratory rate for predicting weaning outcomes

Objective

Clinicians cannot precisely determine the time for withdrawal of ventilation. We aimed to evaluate the performance of driving pressure (DP)×respiratory rate (RR) to predict the outcome of weaning.

Methods

Plateau pressure (Pplat) and total positive end-expiratory pressure (PEEPtot) were measured during mechanical ventilation with brief deep sedation and on volume-controlled mechanical ventilation with a tidal volume of 6 mL/kg and a PEEP of 0 cmH₂O. Pplat and PEEPtot were measured by patients holding their breath for 2 s after inhalation and exhalation, respectively. DP was determined as Pplat minus PEEPtot. The rapid shallow breathing index was measured from the ventilator. The highest RR was recorded within 3 minutes during a spontaneous breathing trial. Patients who tolerated a spontaneous breathing trial for 1 hour were extubated.

Results

Among the 105 patients studied, 44 failed weaning. During ventilation withdrawal, DP×RR was 136.7±35.2 cmH₂O breaths/minute in the success group and 230.2±52.2 cmH₂O breaths/minute in the failure group. A DP×RR index >170.8 cmH₂O breaths/minute had a sensitivity of 93.2% and specificity of 88.5% to predict failure of weaning.

Conclusions

Measurement of DP×RR during withdrawal of ventilation may help predict the weaning outcome. A high DP×RR increases the likelihood of weaning failure.

Statement: This manuscript was previously posted as a preprint on Research Square with the following link: https://www.researchsquare.com/article/rs-15065/v3 and DOI: 10.21203/rs.2.24506/v3

Beyond Low Tidal Volume Ventilation: Treatment Adjuncts for Severe Respiratory Failure in Acute Respiratory Distress Syndrome

OBJECTIVES

Despite decades of research, the acute respiratory distress syndrome remains associated with significant morbidity and mortality. This Concise Definitive Review provides a practical and evidence-based summary of treatments in addition to low tidal volume ventilation and their role in the management of severe respiratory failure in acute respiratory distress syndrome.

DATA SOURCES

We searched the PubMed database for clinical trials, observational studies, and review articles describing treatment adjuncts in acute respiratory distress syndrome patients, including high positive end-expiratory pressure strategies, recruitment maneuvers, high-frequency oscillatory ventilation, neuromuscular blockade, prone positioning, inhaled pulmonary vasodilators, extracorporeal membrane oxygenation, glucocorticoids, and renal replacement therapy.

STUDY SELECTION AND DATA EXTRACTION

Results were reviewed by the primary author in depth. Disputed findings and conclusions were then reviewed with the other authors until consensus was achieved.

DATA SYNTHESIS

Severe respiratory failure in acute respiratory distress syndrome may present with refractory hypoxemia, severe respiratory acidosis, or elevated plateau airway pressures despite lung-protective ventilation according to acute respiratory distress syndrome Network protocol. For severe hypoxemia, first-line treatment adjuncts include high positive end-expiratory pressure strategies, recruitment maneuvers, neuromuscular blockade, and prone positioning. For refractory acidosis, we recommend initial modest liberalization of tidal volumes, followed by neuromuscular blockade and prone positioning. For elevated plateau airway pressures, we suggest first decreasing tidal volumes, followed by neuromuscular blockade, modification of positive end-expiratory pressure, and prone positioning. Therapies such as inhaled pulmonary vasodilators, glucocorticoids, and renal replacement therapy have significantly less evidence in favor of their use and should be considered second line. Extracorporeal membrane oxygenation may be life-saving in selected patients with severe acute respiratory distress syndrome but should be used only when other alternatives have been applied.

CONCLUSIONS

Severe respiratory failure in acute respiratory distress syndrome often necessitates the use of treatment adjuncts. Evidence-based application of these therapies in acute respiratory distress syndrome remains a significant challenge. However, a rational stepwise approach with frequent monitoring for improvement or harm can be achieved.