Prone-positioning therapy in ARDS

Early, awake proning in emergency department patients with COVID-19

Objective

Proning has been shown to improve oxygenation and mortality in certain populations of intubated patients with acute respiratory distress syndrome. Small observational analyses of COVID-19 patients suggest awake proning may lead to clinical improvement. Data on safety and efficacy is lacking. We sought to describe the effect of proning on oxygenation in nonintubated COVID-19 patients. We also evaluated feasibility, safety, and other physiological and clinical outcomes associated with this intervention.

Methods

We conducted a prospective, observational cohort study of nonintubated patients with COVID-19 who underwent proning per an Emergency Department (ED) clinical protocol. Patients with mild to moderate respiratory distress were included. We calculated change in oxygenation by comparing the oxygen saturation to fraction of inspired oxygen ratio (SpO2:FiO2) during the five minutes prior to proning and first 30 min of proning. We also captured data on respiratory rate, duration of proning, need for intubation, intensive care unit admission, survival to discharge.

Results

Fifty-two patients were enrolled. Thirty were excluded for not meeting protocol inclusion criteria or missing baseline oxygenation data, leaving 22 for analysis. The SpO2:FiO2 ratio increased by a median of 5 (IQR: 0–15) in the post-proning period compared to the pre-proning period (median: 298 (IQR: 263–352) vs 295 (IQR: 276–350), p = 0.01). Respiratory rate did not change significantly between time periods. No immediate adverse events occurred during proning. Five patients (23%) were intubated within 48 h of admission.

Conclusion

Early, awake proning may be feasible in select COVID-19 patients and was associated with improved oxygenation.

Proning Patients With COVID-19: A Review of Equipment and Methods

OBJECTIVE

To identify and critically evaluate methods for proning patients with COVID-19 in the intensive care unit (ICU).

BACKGROUND

Acute respiratory distress syndrome (ARDS) is common in hospitalized patients with COVID-19. Proning improves blood oxygenation and survival rates in these patients but is not commonly performed due to the difficulty of the procedure.

METHODS

An academic literature review, internet video search, and consultation with five subject-matter experts was performed to identify known methods for proning. Evaluation of each method considered the number of healthcare workers required, physical stresses on staff, risk of adverse events to patients, and equipment cost and availability.

RESULTS

Several variations of manual techniques and-lift assisted techniques were identified in addition to a specialized proning bed. Manual methods require more healthcare workers, higher physical stresses, and greater risk of adverse events than lift-assisted methods or the proning bed.

CONCLUSION

Both the specialized proning bed and a lift-assisted method using straps largely eliminated manual forces required for proning while allowing for a controlled lowering and positioning of the patient.

APPLICATION

This review will guide practitioners to the most suitable methods for proning patients in the ICU.

Optimal Strategies for Severe Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) occurs in more than 10% of intensive care unit admissions and in nearly 25% of ventilated patients. Mortality remains high at 40%, and, for patients who survive, recovery continues for months or even years. Early recognition and minimizing further lung injury remain essential to successful management of severe ARDS. Advanced treatment strategies, which complement lung protective ventilation, include short-term neuromuscular blockade, prone positioning, and extracorporeal membrane oxygenation. Alternative ventilator strategies include high-frequency ventilation and airway pressure release ventilation. This article reviews these options in patients with severe ARDS.

Good practices for prone positioning at the bedside: Construction of a care protocol

Last year, interest in prone positioning to treat acute respiratory distress syndrome (ARDS) resurfaced with the demonstration of a reduction in mortality by a large randomized clinical trial. Reports in the literature suggest that the incidence of adverse events is significantly reduced with a team trained and experienced in the process. The objective of this review is to revisit the current evidence in the literature, discuss and propose the construction of a protocol of care for these patients. A search was performed on the main electronic databases: Medline, Lilacs and Cochrane Library. Prone positioning is increasingly used in daily practice, with properly trained staff and a well established care protocol are essencial.

Management of Respiratory Failure

The management of acute respiratory failure varies according to the etiology. A clear understanding of physiology of respiration and pathophysiological mechanisms of respiratory failure is mandatory for managing these patients. The extent of abnormality in arterial blood gas values is a result of the balance between the severity of disease and the degree of compensation by cardiopulmonary system. Normal blood gases do not mean that there is an absence of disease because the homeostatic system can compensate. However, an abnormal arterial blood gas value reflects uncompensated disease that might be life threatening.

Regional lung volume differences between the side-lying and semi-prone positions

[Purpose] This study aimed to clarify the differences in regional lung volume between the semi-prone (Sim's position) and side-lying position, and the optimal position for increasing lung volume. [Methods] Measurements were performed in both positions on both sides. Sim's position was inclined 45° forward from the side-lying position. A 1.5-T system with a fast advanced spin-echo sequence in the coronal plane was used for magnetic resonance imaging. [Results] The two positions did not significantly differ in total lung capacity and its subdivisions on both sides, except the left lung in the right side-lying position and right Sim's position. In the nondependent lung, the percentage lung volume of the dorsal segment was significantly higher in the right Sim's position than in the right side-lying position. However, no significant difference was observed between the left side-lying and left Sim's position. [Conclusion] The heart was displaced ventrally by gravity in Sim's position and leaned on the ventral parapet. The spaces for the expansion of the ventral and dorsal segments of the lung were decreased and increased in Sim's position, respectively. With a nondependent left lung, the increase in the percentage lung volume of the dorsal segment was greater in Sim's position than in the side-lying position.

Management of refractory hypoxemia during venovenous extracorporeal membrane oxygenation for ARDS

Venovenous extracorporeal membrane oxygenation (VV ECMO) in acute respiratory distress syndrome (ARDS) is currently a widely used therapeutic strategy. However, patients are often still hypoxemic despite complete ECMO support. The major determinants of peripheral oxygen saturation (SpO2) during VV ECMO are pump flow, degree of recirculation, patient's systemic venous return and its oxygen saturation, hemoglobin concentration and residual lung function. Current guidelines state that the support can be considered adequate when the patient's SpO2 is equal or greater than 80%, but a possible objection could be that such a value of O2-tension may be too low and may worsen the patient's prognosis. Moving from the pathophysiology of hypoxemia during VV ECMO, this review focuses on recirculation of blood and on the possible strategies to minimize it, on the pharmacologic modulation of intrapulmonary shunt and on the questions related to management of ECMO flow and the risks and benefits of permissive hypoxemic states. Transfusional strategy during VV ECMO, administration of neuromuscular blocking agents and sedatives, therapeutic hypothermia, and prone positioning is also reviewed. The potential advantages of β-blockers are discussed. Finally, transition from VV ECMO to venoarterial ECMO (VA ECMO) or a hybrid configuration is also examined.

The effects of prone position ventilation in patients with acute respiratory distress syndrome. A systematic review and metaanalysis

INTRODUCTION

Prone position ventilation has been shown to improve oxygenation and ventilatory mechanics in patients with acute respiratory distress syndrome. We evaluated whether prone ventilation reduces the risk of mortality in adult patients with acute respiratory distress syndrome versus supine ventilation.

METHODOLOGY

A metaanalysis of randomized controlled trials comparing patients in supine versus prone position was performed. A search was conducted of the Pubmed, Embase, Cochrane Library, and LILACS databases. Mortality, hospital length of stay, days of mechanical ventilation and adverse effects were evaluated.

RESULTS

Seven randomized controlled trials (2,119 patients) were included in the analysis. The prone position showed a nonsignificant tendency to reduce mortality (OR: 0.76; 95%CI: 0.54 to 1.06; P=.11, I(2) 63%). When stratified by subgroups, a significant decrease was seen in the risk of mortality in patients ventilated with low tidal volume (OR: 0.58; 95%CI: 0.38 to 0.87; P=.009, I(2) 33%), prolonged pronation (OR: 0.6; 95%CI: 0.43 to 0.83; p=.002, I(2) 27%), start within the first 48hours of disease evolution (OR 0.49; 95%CI 0.35 to 0.68; P=.0001, I(2) 0%) and severe hypoxemia (OR: 0.51: 95%CI: 0.36 to 1.25; P=.0001, I(2) 0%). Adverse effects associated with pronation were the development of pressure ulcers and endotracheal tube obstruction.

CONCLUSIONS

Prone position ventilation is a safe strategy and reduces mortality in patients with severely impaired oxygenation. It should be started early, for prolonged periods, and should be associated to a protective ventilation strategy.

Therapeutic effect of intravenous infusion of perfluorocarbon emulsion on LPS-induced acute lung injury in rats

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS) are the leading causes of death in critical care. Despite extensive efforts in research and clinical medicine, mortality remains high in these diseases. Perfluorocarbon (PFC), a chemical compound known as liquid ventilation medium, is capable of dissolving large amounts of physiologically important gases (mainly oxygen and carbon dioxide). In this study we aimed to investigate the effect of intravenous infusion of PFC emulsion on lipopolysaccharide (LPS) induced ALI in rats and elucidate its mechanism of action. Forty two Wistar rats were randomly divided into three groups: 6 rats were treated with saline solution by intratracheal instillation (control group), 18 rats were treated with LPS by intratracheal instillation (LPS group) and the other 18 rats received PFC through femoral vein prior to LPS instillation (LPS+PFC group). The rats in the control group were sacrificed 6 hours later after saline instillation. At 2, 4 and 6 hours of exposure to LPS, 6 rats in the LPS group and 6 rats in LPS+PFC group were sacrificed at each time point. By analyzing pulmonary pathology, partial pressure of oxygen in the blood (PaO2) and lung wet-dry weight ratio (W/D) of each rat, we found that intravenous infusion of PFC significantly alleviated acute lung injury induced by LPS. Moreover, we showed that the expression of pulmonary myeloperoxidase (MPO), intercellular adhesion molecule-1 (ICAM-1) of endothelial cells and CD11b of polymorphonuclear neutrophils (PMN) induced by LPS were significantly decreased by PFC treatment in vivo. Our results indicate that intravenous infusion of PFC inhibits the infiltration of PMNs into lung tissue, which has been shown as the core pathogenesis of ALI/ARDS. Thus, our study provides a theoretical foundation for using intravenous infusion of PFC to prevent and treat ALI/ARDS in clinical practice.

[Management of postoperative complications following esophagectomy]

Complications following esophagectomy significantly affect the outcome, including perioperative mortality, costs and survival. Pulmonary complications and anastomotic leaks still remain the most serious complications and early recognition and appropriate initial treatment are essential. Mortality associated with esophageal leaks is decreasing due in part to the increased use of computed tomography (CT) scanning and endoscopy for diagnosis and subsequent appropriate multidisciplinary therapy. In this respect, it is critically important to differentiate between leaks and conduit necrosis, and endoscopic examination is the best method for making this assessment. Endoscopic and interventional radiology techniques are being applied increasingly for detection of intrathoracic leaks but appropriate patient selection is important. Adequate external drainage of the leak and prevention of further contamination are the primary therapeutic goals. The spectrum of therapeutic options ranges from simple conservative treatment for smaller, well drained leaks, interventional placement of drains, to endoscopic intervention with closure of the fistula or placement of stents and reoperation or discontinuity resection for conduit necrosis.