Electrical Impedance Tomography to Monitor Hypoxemic Respiratory Failure

Hypoxemic respiratory failure is one of the leading causes of mortality in intensive care. Frequent assessment of individual physiological characteristics and delivery of personalized mechanical ventilation (MV) settings is a constant challenge for clinicians caring for these patients. Electrical impedance tomography (EIT) is a radiation-free bedside monitoring device that is able to assess regional lung ventilation and changes in aeration. With real-time tomographic functional images of the lungs obtained through a thoracic belt, clinicians can visualize and estimate the distribution of ventilation at different ventilation settings or following procedures such as prone positioning. Several studies have evaluated the performance of EIT to monitor the effects of different MV settings in patients with acute respiratory distress syndrome, allowing more personalized MV. For instance, EIT could help clinicians find the positive end-expiratory pressure that represents a compromise between recruitment and overdistension and assess the effect of prone positioning on ventilation distribution. The clinical impact of the personalization of MV remains to be explored. Despite inherent limitations such as limited spatial resolution, EIT also offers a unique noninvasive bedside assessment of regional ventilation changes in the ICU. This technology offers the possibility of a continuous, operator-free diagnosis and real-time detection of common problems during MV. This review provides an overview of the functioning of EIT, its main indices, and its performance in monitoring patients with acute respiratory failure. Future perspectives for use in intensive care are also addressed.

Extracorporeal membrane oxygenation circuits in parallel for refractory hypoxemia in patients with COVID-19

OBJECTIVES

Refractory hypoxemia can occur in patients with acute respiratory distress syndrome from COVID-19 despite support with venovenous (VV) extracorporeal membrane oxygenation (ECMO). Parallel ECMO circuits can be used to increase physiologic support. We report our clinical experience using ECMO circuits in parallel for select patients with persistent severe hypoxemia despite the use of a single ECMO circuit.

METHODS

We performed a retrospective cohort study of all patients with COVID-19-related acute respiratory distress syndrome who received VV-ECMO with an additional circuit in parallel at Vanderbilt University Medical Center between March 1, 2020, and March 1, 2022. We report demographic characteristics and clinical characteristics including ECMO settings, mechanical ventilator settings, use of adjunctive therapies, and arterial blood gas results after initial cannulation, before and after receipt of a second ECMO circuit in parallel, and before removal of the circuit in parallel, and outcomes.

RESULTS

Of 84 patients with COVID-19 who received VV-ECMO during the study period, 22 patients (26.2%) received a circuit in parallel. The median duration of ECMO was 40.0 days (interquartile range, 31.6-53.1 days), of which 19.0 days (interquartile range, 13.0-33.0 days) were spent with a circuit in parallel. Of the 22 patients who received a circuit in parallel, 16 (72.7%) survived to hospital discharge and 6 (27.3%) died before discharge.

CONCLUSIONS

In select patients, the additional use of an ECMO circuit in parallel can increase ECMO blood flow and improve oxygenation while allowing for lung-protective mechanical ventilation and excellent outcomes.

Severe pulmonary hypertension and circulatory failure associated with Congenital syphilis. Case report

BACKGROUND

Congenital syphilis is a vertical infection caused by Treponema pallidum. Despite the implementation of preventive strategies during pregnancy, its incidence is increasing, and it constitutes an important public health problem. Most patients with congenital syphilis are asymptomatic; however, a small group may develop severe disease at birth with the need of advanced resuscitation in the delivery room, acute hypoxemic respiratory failure, and hemodynamic instability. Therefore, awareness is needed.

METHODS AND RESULTS

This series describes the clinical course of two late preterm infants with congenital syphilis who developed acute hypoxemic respiratory failure, pulmonary hypertension, and circulatory collapse early after birth. Integrated hemodynamic evaluation with neonatologist-performed echocardiography (NPE) and therapeutic management is provided.

CONCLUSIONS

A comprehensive hemodynamic evaluation including early and serial functional echocardiography in these patients is needed to address the underlying complex pathophysiology and to help to establish accurate treatment.

Oxygenation saturation index in neonatal hypoxemic respiratory failure

BACKGROUND

This study aimed to assess the validity of the oxygenation saturation index (OSI) and the ratio of oxygen saturation to the fraction of inspired oxygen (FIO2) (S/F ratio) with percutaneous oxygen saturation (OSISpO2 and the Sp/F ratio) and to evaluate the correlation between these values and the oxygen index (OI). It also determined their cut-off values for predicting OI in accordance with neonatal hypoxic respiratory failure severity.

METHODS

We reviewed the data of 77 neonates (gestational age 31.7 ± 6.1 weeks; birthweight, 1768 ± 983 g) requiring invasive mechanical ventilation between 2013 and 2020, 1233 arterial blood gas samples in total. We calculated the OI, OSISpO2, OSI with arterial oxygen saturation (SaO2) (OSISaO2), Sp/F ratio, and the ratio of SaO2 to FIO2 (Sa/F ratio).

RESULTS

The regression and Bland-Altman analysis showed good agreement between OSISpO2 or the Sp/F ratio and OSISaO2 or the Sa/F ratio. Although a significant positive correlation was found between OSISpO2 and OI, OSISpO2 was overestimated in SpO2 > 98% with a higher slope of the fitted regression line than that below 98% of SpO2. Furthermore, receiver-operating characteristic curve analysis using only SpO2 ≤ 98% samples showed that the optimal cut-off points of OSISpO2 and the Sp/F ratio for predicting OI were: OI 5, 3.0 and 332; OI 10, 5.3 and 231; OI 15, 7.7 and 108; OI 20, 11.0 and 149; and OI 25, 17.1 and 103, respectively.

CONCLUSION

The cut-off OSISpO2 and Sp/F ratio values could allow continuous monitoring for oxygenation changes in neonates with the potential for wider clinical applications.

Designing a Behaviour Change Wheel guided implementation strategy for a hypoxaemic respiratory failure and ARDS care pathway that targets barriers

BACKGROUND

A significant gap exists between ideal evidence-based practice and real-world application of evidence-informed therapies for patients with hypoxaemic respiratory failure (HRF) and acute respiratory distress syndrome (ARDS). Pathways can improve the quality of care provided by helping integrate and organise the use of evidence informed practices, but barriers exist that can influence their adoption and successful implementation. We sought to identify barriers to the implementation of a best practice care pathway for HRF and ARDS and design an implementation science-based strategy targeting these barriers that is tailored to the critical care setting.

METHODS

The intervention assessed was a previously described multidisciplinary, evidence-based, stakeholder-informed, integrated care pathway for HRF and ARDS. A survey questionnaire (12 open text questions) was administered to intensive care unit (ICU) clinicians (physicians, nurses, respiratory therapists) in 17 adult ICUs across Alberta. The Behaviour Change Wheel, capability, opportunity, motivation - behaviour components, and Theoretical Domains Framework (TDF) were used to perform qualitative analysis on open text responses to identify barriers to the use of the pathway. Behaviour change technique (BCT) taxonomy, and Affordability, Practicality, Effectiveness and cost-effectiveness, Acceptability, Side effects and safety and Equity (APEASE) criteria were used to design an implementation science-based strategy specific to the critical care context.

RESULTS

Survey responses (692) resulted in 16 belief statements and 9 themes with 9 relevant TDF domains. Differences in responses between clinician professional group and hospital setting were common. Based on intervention functions linked to each belief statement and its relevant TDF domain, 26 candidate BCTs were identified and evaluated using APEASE criteria. 23 BCTs were selected and grouped to form 8 key components of a final strategy: Audit and feedback, education, training, clinical decision support, site champions, reminders, implementation support and empowerment. The final strategy was described using the template for intervention description and replication framework.

CONCLUSIONS

Barriers to a best practice care pathway were identified and were amenable to the design of an implementation science-based mitigation strategy. Future work will evaluate the ability of this strategy to improve quality of care by assessing clinician behaviour change via better adherence to evidence-based care.

Regional moderate hyperthermia for mild-to-moderate COVID-19 (TherMoCoV study): a randomized controlled trial

Background

To prevent COVID-19 progression, low-cost alternatives that are available to all patients are needed. Diverse forms of thermotherapy have been proposed to prevent progression to severe/critical COVID-19.

Objective

The aim of this study is to evaluate the efficacy and safety of local thermotherapy to prevent disease progression in hospitalized adult patients with mild-to-moderate COVID-19.

Methods

A multicenter, open-label, parallel-group, randomized, adaptive trial is used to evaluate the efficacy and safety of local thermotherapy to prevent disease progression in hospitalized adult patients with mild-to-moderate COVID-19. Eligible hospitalized adult patients with symptoms of COVID-19 with ≤5 days from symptom onset, meeting criteria for mild or moderate COVID-19, were randomly assigned to the intervention consisting of local thermotherapy via an electric heat pad in the thorax (target temperature range 39.5–42°C) continuously for 90 min, twice daily, for 5 days, or standard care. The main outcome was the proportion of patients who progressed to severe-to-critical COVID-19 or death. Patients were randomized in a 1:1 ratio through a centralized computer-generated sequence of minimization with a random component of 20%. Participants and medical staff were not blinded to the intervention.

Results

One-hundred and five participants (thermotherapy n = 54, control n = 51) with a median age of 53 (IQR: 41–64) years were included for analysis after the early cessation of recruitment due to the closure of all temporal COVID-19 units (target sample size = 274). The primary outcome of disease progression occurred in 31.4% (16/51) of patients in the control group vs. 25.9% (14/54) of those receiving thermotherapy (risk difference = 5.5%; 95%CI: −11.8–22.7, p = 0.54). Thermotherapy was well tolerated with a median total duration of thermotherapy of 900 (IQR: 877.5–900) min. Seven (13.7%) patients in the control group and seven (12.9%) in the thermotherapy group had at least one AE (p = 0.9), none of which were causally attributed to the intervention. No statistically significant differences in serum cytokines (IL-1β, IL-6, IL-8, IL-10, IL-17, and IFN-γ) were observed between day 5 and baseline among groups.

Conclusion

Local thermotherapy was safe and well-tolerated. A non-statistically significant lower proportion of patients who experienced disease progression was found in the thermotherapy group compared to standard care. Local thermotherapy could be further studied as a strategy to prevent disease progression in ambulatory settings.

Clinical Trial registration: www.clinicaltrials.gov, identifier: NCT04363541.

A Survey of Feeding Practices During High-Flow Nasal Cannula Oxygen Therapy

BACKGROUND

High-flow nasal cannula (HFNC) oxygen therapy is used to deliver warm and humidified gases to patients in respiratory failure. A purported advantage of HFNC oxygen therapy is that it can allow for oral feeding while on the device, although few data support this practice. The purpose of this study was to identify practices and opinions with regard to feeding practices during HFNC oxygen therapy.

METHODS

A survey related to the practice and opinions of feeding practices during HFNC oxygen therapy was developed and sent to respiratory therapists, speech-language pathologists, physicians, advanced practice providers, and registered dietitians.

RESULTS

Respondents included 307 professionals from 14 different countries. Most respondents worked in an academic/teaching hospital (n = 174 [56.7%]) with patients ages ≥ 18 years (n = 282 [91.9%]). Most respondents stated that their institution did not have a specific feeding protocol for HFNC oxygen therapy (n = 246 [80.4%]) and felt that patients could have an oral diet during HFNC oxygen therapy if not in imminent danger of being intubated (n = 264 [86.3%]). Fewer than half of the respondents felt that patients should have a bedside/clinical swallow examination before eating and/or drinking during HFNC oxygen therapy (n = 143 [46.7%]). By profession, most physicians/advanced practice providers (n = 67 [59.3%]), respiratory therapists (n = 37 [62.7%]) and half of the registered dietitians (n = 16 [50%]) felt that bedside/clinical swallow examinations were unnecessary before eating and/or drinking with HFNC, but speech-language pathologists were in favor (n = 77 [75.5%]).

CONCLUSIONS

Most facilities did not have a protocol to guide feeding practices when HFNC oxygen therapy is used. Most clinicians felt that an oral diet is safe for stable patients not in danger of being intubated. In general, speech-language pathologists felt that patients on HFNC oxygen therapy should undergo a bedside/clinical swallow examination before eating and/or drinking.

Pulmonary Vascular Phenotypes of Prematurity: The Path to Precision Medicine

Pulmonary hypertension (PH) is associated with significant morbidities and high mortality in preterm infants, yet mechanisms contributing to the pathogenesis of PH, the impact of early pulmonary vascular disease (PVD) on the risk for BPD, the role for PH-targeted drug therapies, and long-term pulmonary vascular sequelae remain poorly understood. PVD is not a homogeneous disease, rather, PVD in the setting of prematurity includes various phenotypes as based on underlying pathophysiology, the severity of associated PH, the timing of disease onset, its contribution to hemodynamic and respiratory status, late outcomes, and other features. As with term newborns, severe hypoxemia with acute respiratory failure (HRF) in preterm infants can be due to marked elevation of pulmonary artery pressure with extrapulmonary shunt, traditionally referred to as persistent pulmonary hypertension of the newborn (PPHN). Transient and less severe levels of PH can also be observed during the early transition after birth without evidence of severe HRF, representing physiologic PH or delayed pulmonary vascular transition in preterm infants. Importantly, echocardiographic evidence of early PH has been strongly associated with the subsequent development of bronchopulmonary dysplasia (BPD), late PH, and chronic respiratory disease during infancy and early childhood. Late PH beyond the first postnatal months in preterm in neonates with established BPD is further associated with poor outcomes, especially as related to BPD severity. In addition, echocardiographic signs of PVD can further persist throughout childhood and may lead to chronic PH of variable severity and cardiac maldevelopment in prematurely born young adults. This review discusses the importance of characterizing diverse pulmonary vascular phenotypes in preterm infants to better guide clinical care and research, and to enhance the development of more precise therapeutic strategies to optimize early and late outcomes of preterm infants.

Erratum: Effects of awake prone position vs. usual care on acute hypoxemic respiratory failure in patients with COVID-19: a systematic review and meta-analysis of randomized controlled trials

[This corrects the article DOI: 10.3389/fmed.2023.1120837.].

Optimizing Tracheal Oxygen Tension and Diffusion Ratio When Choosing High-Flow Oxygen Therapy or CPAP for the Treatment of Hypoxemic Respiratory Failure: Insights from Ex Vivo Physiologic Modelling

This article is a review of the physiological and technological processes underpinning high-flow nasal therapy with oxygen (HFNT or HFOT) for the treatment of hypoxemic respiratory failure. A mathematical model was carefully built to represent the relationships between the settings on the HFNT device and the resultant diffusion of oxygen into hypoxemic, arterial blood. The analysis was used to recommend a strategy for setting the flow rate at or above the patient's peak inspiratory flow when HFNT is used with a blender and equal to the patient's peak inspiratory rate when bleed-in oxygen is used. The analysis also teaches how to titrate the settings to achieve a desired fraction of inhaled oxygen, (FiO2), in the trachea using a simple ratio when bleed-in oxygen is used. The model was used to compare HFNT as a method to improve oxygen diffusion efficacy with other forms of oxygen therapy. The analysis in this article relates the efficacy of HFOT/HFNT to that of CPAP with supplemental oxygen by computing the diffusion ratio of oxygen therapy versus breathing room air. We predicted that in non-atelectatic lungs, when considering oxygenation, HFNT can be equally effective as CPAP with supplemental oxygen therapy for treating hypoxemic respiratory failure.

Alveolar dead space fraction is not associated with early RV systolic dysfunction in pediatric ARDS

PRIMARY HYPOTHESIS

We hypothesized that higher alveolar dead space fraction (AVDSf) at pediatric acute respiratory distress syndrome (PARDS) onset would be associated with right ventricular (RV) systolic dysfunction within the first 24 h of PARDS.

STUDY DESIGN AND METHODS

We performed a retrospective single-center cohort study of PARDS patients with clinically obtained echocardiograms within 24 h. Primary exposure was AVDSf at PARDS onset. Primary outcome was RV systolic dysfunction as defined by RV global longitudinal strain (GLS) (>-18%). Secondary outcomes included pulmonary hypertension (PH) and RV systolic dysfunction as defined by other echocardiogram parameters, and measures of oxygenation. Unadjusted and adjusted logistic and linear regression were used to investigate AVDSf associations with outcomes.

RESULTS

Ninety-one patients were included: median age 6.2 years, 46% female, and 65% with moderate or severe PARDS. Median AVDSf was 0.2 (interquartile range [IQR] 0.0-0.3), 33% had RV dysfunction, and 21% had PH. Unadjusted and adjusted logistic regression showed no association between AVDSf and RV systolic dysfunction or PH by any echocardiographic measure, but unadjusted and adjusted linear regression did show an association between AVDSf and PaO2 /FiO2 .

CONCLUSION

AVDSf at PARDS onset was not associated with RV systolic dysfunction or PH within 24 h but was associated with PaO2 /FiO2 ratio and may be more reflective of pulmonary causes of ventilation-perfusion mismatch. Future investigations should focus on clarifying the clinical utility of AVDSf in relation to existing metrics throughout the course of PARDS.

Therapeutic response of iNO in preterm infants with hypoxemic respiratory failure

BACKGROUND

Inhaled nitric oxide (iNO) has been used as a rescue treatment for preterm infants with hypoxemic respiratory failure (HRF). However, its effectiveness remains debatable. Thus, in this study, we aimed to examine the impact of iNO therapy on HRF in extremely preterm infants.

METHODS

A retrospective observational study was performed. Extremely preterm infants admitted to our neonatal intensive care unit who received iNO therapy later in their postnatal life were included. The oxygen saturation index (OSI) was used as an index of the severity of respiratory failure.

RESULTS

In total, 30 extremely preterm infants were included in this study. Oxygenation was enhanced after the administration of iNO in infants with HRF. The OSI decreased by more than 20% in 12 patients (40%, positive responder) and did not decrease in 17 patients (57%, negative responder) within the first 6 h of treatment. The iNO initiation day was the significant independent factor associated with a positive response to iNO therapy in extremely preterm infants with HRF.

CONCLUSIONS

iNO therapy was effective in enhancing oxygenation in extremely preterm infants with HRF. Earlier use of iNO was the significant factor associated with a positive therapeutic response to iNO, implying that iNO may be more effective in pulmonary vessels which are less damaged by shorter-term mechanical ventilation.

The role of prone positioning in patients with SARS-CoV-2-related respiratory failure in non-intensive care unit

BACKGROUND

Prone positioning (PP) is an established and commonly used lung recruitment method for intubated patients with severe acute respiratory distress syndrome, with potential benefits in clinical outcome. The role of PP outside the intensive care unit (ICU) setting is debated.

OBJECTIVES

We aimed at assessing the role of PP in death and ICU admission in non-intubated patients with acute respiratory failure related to COronaVIrus Disease-19 (COVID-19) pneumonia.

DESIGN

This is a retrospective analysis of a collaborative multicenter database obtained by merging local non-interventional cohorts.

METHODS

Consecutive adult patients with COVID-19-related respiratory failure were included in a collaborative cohort and classified based on the severity of respiratory failure according to the partial arterial oxygen pressure to fraction of inspired oxygen ratio (PaO₂/FiO₂) and on clinical severity by the quick Sequential Organ Failure Assessment (qSOFA) score. The primary study outcome was the composite of in-hospital death or ICU admission within 30 days from hospitalization.

RESULTS

PP was used in 114 of 536 study patients (21.8%), more commonly in patients with lower PaO₂/FiO₂ or receiving non-invasive ventilation and less commonly in patients with known comorbidities. A primary study outcome event occurred in 163 patients (30.4%) and in-hospital death in 129 (24.1%). PP was not associated with death or ICU admission (HR 1.17, 95% CI 0.78-1.74) and not with death (HR 1.01, 95% CI 0.61-1.67) at multivariable analysis; PP was an independent predictor of ICU admission (HR 2.64, 95% CI 1.53-4.40). The lack of association between PP and death or ICU admission was confirmed at propensity score-matching analysis.

CONCLUSION

PP is used in a non-negligible proportion of non-intubated patients with COVID-19-related severe respiratory failure and is not associated with death but with ICU admission. The role of PP in this setting merits further evaluation in randomized studies.

Effects of awake prone position vs. usual care on acute hypoxemic respiratory failure in patients with COVID-19: A systematic review and meta-analysis of randomized controlled trials

Background

Previous studies have shown that an awake prone position may be beneficial for the treatment of acute respiratory distress syndrome (ARDS) or acute hypoxic respiratory failure (AHRF) in patients with COVID-19, but the results are not consistent, especially in terms of oxygenation outcomes and intubation rate. This systematic review and meta-analysis assessed the effects of the awake prone position on AHRF in patients with COVID-19 with all randomized controlled trials (RCTs).

Methods

An extensive search of online databases, including MEDLINE, Embase, Web of Science, and Cochrane Central Register of Controlled Trials from 1 December 2019 to 30 October 2022, with no language restrictions was performed. This systematic review and meta-analysis are based on the PRISMA statement. We only included RCTs and used the Cochrane risk assessment tool for quality assessment.

Results

Fourteen RCTs fulfilled the selection criteria, and 3,290 patients were included. A meta-analysis found that patients in the awake prone position group had more significant improvement in the SpO₂/FiO₂ ratio [mean difference (MD): 29.76; 95% confidence interval (CI): 1.39-48.13; P = 0.001] compared with the usual care. The prone position also reduced the need for intubation [odd ratio (OR): 0.72; 95% CI: 0.61 to 0.84; P < 0.0001; I ² = 0%]. There was no significant difference in mortality, hospital length of stay, incidence of intensive care unit (ICU) admission, and adverse events between the two groups.

Conclusion

The awake prone position was a promising intervention method, which is beneficial to improve the oxygenation of patients with ARDS or AHRF caused by COVID-19 and reduce the need for intubation. However, the awake prone position showed no obvious advantage in mortality, hospital length of stay, incidence of ICU admission, and adverse events.

Systematic review registration

International Prospective Register of Systematic Reviews (PROSPERO), identifier: CRD42022367885.

Autologous blood-patch pleurodesis for persistent air leak in an AIDS patient with pneumothorax

Autologous blood-patch pleurodesis (ABPP) is a common technique used to manage patients with persistent pleural air leaks caused by pneumothorax. Other treatment options for persistent air leak (PAL) include chemical pleurodesis or placement of endobronchial valves, though severity of illness, risk of complications such as infection, or patient comorbidities may impact treatment decisions. The use of ABPP in patients with HIV and AIDS has not been reported in the literature. We present a case of a 32-year-old man with a history of AIDS (noncompliant with medications) and schizophrenia who presented with acute hypoxemic respiratory failure complicated by pneumothorax and PAL. He safely underwent ABPP without complications and eventually had resolution of PAL.

Platypnea-Orthodeoxia Syndrome: A Rare Cause of Positional Respiratory Failure

Platypnea-orthodeoxia syndrome (POS) is a rare clinical entity characterized by dyspnea and arterial desaturation in the upright position. Hypoxia in POS has been attributed to the mixing of deoxygenated venous with oxygenated arterial blood via a shunt, with patent foramen ovale being the most commonly reported abnormality. A systematic evaluation is necessary to identify the underlying cause and promote an appropriate intervention. Here, we present the case of a 79-year-old female with a new diagnosis of POS during the workup of hypoxemic respiratory failure.

Combined Noninvasive Respiratory Support Therapies to Treat COVID-19

BACKGROUND

The roles of high-flow nasal cannula (HFNC) and CPAP in coronavirus disease 2019 (COVID-19) are controversial. The objective of the study was to evaluate the impact of the application of a noninvasive respiratory support algorithm on clinical outcomes in subjects with COVID-19 and with acute respiratory failure.

METHODS

We performed a single-center prospective observational study of subjects with respiratory failure from COVID-19 managed with HFNC and with CPAP plus HFNC (combined therapy). The main outcome was the intubation rate, which defined failure of therapy. We also analyzed the role of the ROX index ([[Formula: see text]/[Formula: see text]]/breathing frequency) to predict the need for intubation.

RESULTS

From June to December 2020, 113 subjects with COVID-19 respiratory failure were admitted to our respiratory intermediate care unit. HFNC was applied in 65 subjects (57.52%) and combined therapy in 48 subjects (42.47%). A total of 83 subjects (73.45%) were successfully treated with noninvasive respiratory support. The intubation rate was 26.54%, and the overall mortality rate was 14.15%. The mortality rate in subjects who were intubated was 55.2%. An ROX index of 6.28 at 12 h predicted noninvasive respiratory support failure, with 97.6% sensitivity and 51.8% specificity.

CONCLUSIONS

Data from our cohort managed in a respiratory intermediate care unit showed that combined noninvasive respiratory support was feasible, with favorable outcomes. Further prospective studies are required.

Response to Awake Prone Position in Nonintubated Individuals With COVID-19

BACKGROUND

Prone positioning is used for patients with ARDS undergoing invasive mechanical ventilation; its effectiveness in nonventilated awake patients is unclear. We aimed to evaluate the effectiveness of the prone maneuver in decreasing the risk of intubation and increasing the odds of favorable events.

METHODS

We prospectively evaluated 66 subjects with COVID-19-related moderate ARDS who were admitted to the ICU; treated with high-flow nasal cannula, noninvasive ventilation, a reservoir mask, or a nasal cannula; and subjected to awake prone maneuvers from March 1, 2020-August 30, 2020. The following factors were recorded at ICU admission: age, sex, prior illness, simplified acute physiology score 3, body mass index, and changes in gas exchange after and before prone positioning. Subjects were divided into a group of responders and nonresponders according to a 20% increase in the P_aO2 /F_IO2 ratio before and after the maneuver. The need for intubation within 48 h of the start of the maneuver was also evaluated. We also analyzed the differences in mortality, ICU length of stay, hospital length of stay, and duration of mechanical ventilation. A generalized estimating equation model was applied to preprone and postprone means. To control for confounding factors, multivariate Poisson regression was applied.

RESULTS

Forty-one subjects age 54.1 y ± 12.9 were enrolled. Responders showed increased S_pO2 (P < .001), P_aO2 (P < .001), and P_aO2 /F_IO2 ratios (P < .001) with the maneuver and reduced breathing frequency. Responders had shorter lengths of stay in the ICU (P < .001) and hospital (P < .003), lower intubation rates at 48 h (P < .012), fewer days of ventilation (P < .02), and lower mortality (P < .001). Subjects who responded to the maneuver had a 54% reduction in the risk of ventilation and prolonged stay in the ICU.

CONCLUSIONS

Among the responders to prone positioning, there were fewer deaths, shorter duration of mechanical ventilation, shorter ICU length of stay, and shorter hospital length of stay.

Prone Positioning of Nonintubated Patients With Coronavirus Disease 2019-A Systematic Review and Meta-Analysis

OBJECTIVES

Several studies have reported prone positioning of nonintubated patients with coronavirus diseases 2019-related hypoxemic respiratory failure. This systematic review and meta-analysis evaluated the impact of prone positioning on oxygenation and clinical outcomes.

DESIGN AND SETTING

We searched PubMed, Embase, and the coronavirus diseases 2019 living systematic review from December 1, 2019, to November 9, 2020.

SUBJECTS AND INTERVENTION

Studies reporting prone positioning in hypoxemic, nonintubated adult patients with coronavirus diseases 2019 were included.

MEASUREMENTS AND MAIN RESULTS

Data on prone positioning location (ICU vs non-ICU), prone positioning dose (total minutes/d), frequency (sessions/d), respiratory supports during prone positioning, relative changes in oxygenation variables (peripheral oxygen saturation, Pao2, and ratio of Pao2 to the Fio2), respiratory rate pre and post prone positioning, intubation rate, and mortality were extracted. Twenty-five observational studies reporting prone positioning in 758 patients were included. There was substantial heterogeneity in prone positioning location, dose and frequency, and respiratory supports provided. Significant improvements were seen in ratio of Pao2 to the Fio2 (mean difference, 39; 95% CI, 25-54), Pao2 (mean difference, 20 mm Hg; 95% CI, 14-25), and peripheral oxygen saturation (mean difference, 4.74%; 95% CI, 3-6%). Respiratory rate decreased post prone positioning (mean difference, -3.2 breaths/min; 95% CI, -4.6 to -1.9). Intubation and mortality rates were 24% (95% CI, 17-32%) and 13% (95% CI, 6-19%), respectively. There was no difference in intubation rate in those receiving prone positioning within and outside ICU (32% [69/214] vs 33% [107/320]; p = 0.84). No major adverse events were recorded in small subset of studies that reported them.

CONCLUSIONS

Despite the significant variability in frequency and duration of prone positioning and respiratory supports applied, prone positioning was associated with improvement in oxygenation variables without any reported serious adverse events. The results are limited by a lack of controls and adjustments for confounders. Whether this improvement in oxygenation results in meaningful patient-centered outcomes such as reduced intubation or mortality rates requires testing in well-designed randomized clinical trials.

Respiratory Mechanics in a Cohort of Critically Ill Subjects With COVID-19 Infection

BACKGROUND

Patients with coronavirus disease 2019 (COVID-19) often develop acute hypoxemic respiratory failure and receive invasive mechanical ventilation. Much remains unknown about their respiratory mechanics, including the trajectories of pulmonary compliance and [Formula: see text]/[Formula: see text], the prognostic value of these parameters, and the effects of prone positioning. We described respiratory mechanics among subjects with COVID-19 who were intubated during the first month of hospitalization.

METHODS

We included patients with COVID-19 who were mechanically ventilated between February and May 2020. Daily values of pulmonary compliance, [Formula: see text], [Formula: see text], and the use of prone positioning were abstracted from electronic medical records. The trends were analyzed separately over days 1-10 and days 1-35 of intubation, stratified by prone positioning use, survival, and initial [Formula: see text]/[Formula: see text].

RESULTS

Among 49 subjects on mechanical ventilation day 1, the mean compliance was 41 mL/cm H₂O, decreasing to 25 mL/cm H₂O by day 14, the median duration of mechanical ventilation. In contrast, the [Formula: see text]/[Formula: see text] on day 1 was similar to day 14. The overall mean compliance was greater among the non-survivors versus the survivors (27 mL/cm H₂O vs 24 mL/cm H₂O; P = .005), whereas [Formula: see text]/[Formula: see text] was higher among the survivors versus the non-survivors over days 1-10 (159 mm Hg vs 138 mm Hg; P = .002) and days 1-35 (175 mm Hg vs 153 mm Hg; P < .001). The subjects who underwent early prone positioning had lower compliance during days 1-10 (27 mL/cm H₂O vs 33 mL/cm H₂O; P < .001) and lower [Formula: see text]/[Formula: see text] values over days 1-10 (139.9 mm Hg vs 167.4 mm Hg; P < .001) versus those who did not undergo prone positioning. After day 21 of hospitalization, the average compliance of the subjects who had early prone positioning surpassed that of the subjects who did not have prone positioning.

CONCLUSIONS

Respiratory mechanics of the subjects with COVID-19 who were on mechanical ventilation were characterized by persistently low respiratory system compliance and [Formula: see text]/[Formula: see text], similar to ARDS due to other etiologies. The [Formula: see text]/[Formula: see text] was more tightly associated with mortality than with compliance.

High-Flow Nasal Cannula Therapy in COVID-19: Using the ROX Index to Predict Success

BACKGROUND

Optimal timing of mechanical ventilation in COVID-19 is uncertain. We sought to evaluate outcomes of delayed intubation and examine the ROX index (ie, [[Formula: see text]]/breathing frequency) to predict weaning from high-flow nasal cannula (HFNC) in patients with COVID-19.

METHODS

We performed a multicenter, retrospective, observational cohort study of subjects with respiratory failure due to COVID-19 and managed with HFNC. The ROX index was applied to predict HFNC success. Subjects that failed HFNC were divided into early HFNC failure (≤ 48 h of HFNC therapy prior to mechanical ventilation) and late failure (> 48 h). Standard statistical comparisons and regression analyses were used to compare overall hospital mortality and secondary end points, including time-specific mortality, need for extracorporeal membrane oxygenation, and ICU length of stay between early and late failure groups.

RESULTS

272 subjects with COVID-19 were managed with HFNC. One hundred sixty-four (60.3%) were successfully weaned from HFNC, and 111 (67.7%) of those weaned were managed solely in non-ICU settings. ROX index >3.0 at 2, 6, and 12 hours after initiation of HFNC was 85.3% sensitive for identifying subsequent HFNC success. One hundred eight subjects were intubated for failure of HFNC (61 early failures and 47 late failures). Mortality after HFNC failure was high (45.4%). There was no statistical difference in hospital mortality (39.3% vs 53.2%, P = .18) or any of the secondary end points between early and late HFNC failure groups. This remained true even when adjusted for covariates.

CONCLUSIONS

In this retrospective review, HFNC was a viable strategy and mechanical ventilation was unecessary in the majority of subjects. In the minority that progressed to mechanical ventilation, duration of HFNC did not differentiate subjects with worse clinical outcomes. The ROX index was sensitive for the identification of subjects successfully weaned from HFNC. Prospective studies in COVID-19 are warranted to confirm these findings and to optimize patient selection for use of HFNC in this disease.

Development and Content Validation of a Multidisciplinary Standardized Management Pathway for Hypoxemic Respiratory Failure and Acute Respiratory Distress Syndrome

Supplemental Digital Content is available in the text.

Objectives:

Treatment of hypoxemic respiratory failure and acute respiratory distress syndrome is complex. Evidence-based therapies that can improve survival and guidelines advocating their use exist; however, implementation is inconsistent. Our objective was to develop and validate an evidence-based, stakeholder-informed standardized management pathway for hypoxemic respiratory failure and acute respiratory distress syndrome to improve adherence to best practice.

Design:

A standardized management pathway was developed using a modified Delphi consensus process with a multidisciplinary group of ICU clinicians. The proposed pathway was externally validated with a survey involving multidisciplinary stakeholders and clinicians.

Setting:

In-person meeting and web-based surveys of ICU clinicians from 17 adult ICUs in the province of Alberta, Canada.

Intervention:

Not applicable.

Measurements and Main Results:

The consensus panel was comprised of 30 ICU clinicians (4 nurses, 10 respiratory therapists, 15 intensivists, 1 nurse practitioner; median years of practice 17 [interquartile range, 13–21]). Ninety-one components were serially rated and revised over two rounds of online and one in-person review. The final pathway included 46 elements. For the validation survey, 692 responses (including 59% nurses, 33% respiratory therapists, 7% intensivists and 1% nurse practitioners) were received. Agreement of greater than 75% was achieved on 43 of 46 pathway elements.

Conclusions:

A 46-element evidence-informed hypoxemic respiratory failure and acute respiratory distress syndrome standardized management pathway was developed and demonstrated to have content validity.

Fluid Balance Predicts Need for Intubation in Subjects With Respiratory Failure Initiated on High-Flow Nasal Cannula

BACKGROUND

High-flow nasal cannula (HFNC) has gained widespread use for acute hypoxemic respiratory failure on the basis of recent publications that demonstrated fewer intubations and perhaps lower mortality in certain situations. However, a subset of patients initiated on HFNC for respiratory failure ultimately do require intubation. Our goal was to identify patient-level features predictive of this outcome.

METHODS

This was a retrospective cohort study of subjects with hypoxemic respiratory failure treated with HFNC. Individuals were described as having succeeded (if weaned from HFNC) or failed (if they required intubation). A variety of easily measurable variables were evaluated for their ability to predict intubation risk, analyzed via a multivariate logistic regression model.

RESULTS

Of a total of 74 subjects, 42 succeeded and 32 failed. The mean ± SD net fluid balance in the first 24 h after HFNC initiation was significantly lower in the success group versus the failure group (-33 ± 80 mL/h vs 72 ± 117 mL/h; P < .01). An adjusted model found only fluid balance and the previously described respiratory rate (breathing frequency [f]) to oxygenation (ROX) index ([[Formula: see text]/[Formula: see text]]/f) at 12 h as significant predictors of successful weaning (negative fluid balance adjusted odds ratio 0.77 [95% CI 0.62-0.96] for -10 mL/h increments [P = .02]; ROX adjusted OR 1.72 [1.15-2.57], P < .01).

CONCLUSIONS

A negative fluid balance while on HFNC discriminated well between those who required intubation versus those who were successfully weaned.

The utility of HACOR score in predicting failure of high-flow nasal oxygen in acute hypoxemic respiratory failure

OBJECTIVES

To assess the diagnostic performance of HACOR scoring system using bedside variables and to predict failure of HFNO in patients with acute hypoxemic respiratory failure (AHRF).

MATERIAL AND METHODS

150 patients with AHRF who were receiving HFNO were enrolled in this study; to predict HFNO treatment failure. A scoring scale (HACOR score) consisted of Heart rate (beats/minute), acidosis (assessed by pH), consciousness (assessed by Glasgow coma score), oxygenation, and respiratory rate. Failure was defined as the need for intubation or death.

RESULTS

Patients were analyzed according to the success or failure of HFNO. Total 150 patients, of which 100 (66.7%) had a successful treatment while 50 (33.3%) failed with such intervention. There was an improvement in HR and RR, and PaO₂/FiO₂ within the first hour (T1) in the success group and these parameters continued to improve even after 24 hours (T2) of HFNO treatment. Patients with HFNO failure had a higher HACOR score at initiation and after 1, 12, 24 and 48 hours. Before intubation, the highest value of the HACOR score was reached in the failure group. At 1h of HFNO assessment, the area under the receiver operating characteristic curve was 0.86, showing good predictive power for failure. We found that HACOR score at a cutoff point > 6 had 81.2% sensitivity and 91% specificity, 92.5% positive predictive value, and 71.4% negative predictive value with a diagnostic accuracy was 85%. Furthermore, the overall diagnostic accuracy exceeded 87% when the HACOR score was assessed at 1, 12, 24 or 48 h of HFNO.

CONCLUSIONS

The HACOR scale is a clinically useful bedside tool for the prediction of HFNO failure in hypoxemic patients. A HACOR score < 6 after 1 hour of HFNO highlights patients with < 85% risk of failure.

Caring for Critically Ill Children With Suspected or Proven Coronavirus Disease 2019 Infection: Recommendations by the Scientific Sections' Collaborative of the European Society of Pediatric and Neonatal Intensive Care

OBJECTIVES

In children, coronavirus disease 2019 is usually mild but can develop severe hypoxemic failure or a severe multisystem inflammatory syndrome, the latter considered to be a postinfectious syndrome, with cardiac involvement alone or together with a toxic shock like-presentation. Given the novelty of severe acute respiratory syndrome coronavirus 2, the causative agent of the recent coronavirus disease 2019 pandemic, little is known about the pathophysiology and phenotypic expressions of this new infectious disease nor the optimal treatment approach.

STUDY SELECTION

From inception to July 10, 2020, repeated PubMed and open Web searches have been done by the scientific section collaborative group members of the European Society of Pediatric and Neonatal Intensive Care.

DATA EXTRACTION

There is little in the way of clinical research in children affected by coronavirus disease 2019, apart from descriptive data and epidemiology.

DATA SYNTHESIS

Even though basic treatment and organ support considerations seem not to differ much from other critical illness, such as pediatric septic shock and multiple organ failure, seen in PICUs, some specific issues must be considered when caring for children with severe coronavirus disease 2019 disease.

CONCLUSIONS

In this clinical guidance article, we review the current clinical knowledge of coronavirus disease 2019 disease in critically ill children and discuss some specific treatment concepts based mainly on expert opinion based on limited experience and the lack of any completed controlled trials in children at this time.

Application of surgical mask with high-flow nasal cannula (HFNC) leads to improved oxygenation in patients with COVID-19: a set of case reports

The new coronavirus SARS-CoV-2 is responsible for the development of acute infectious illness named COVID-19. While most people have a mild course of the disease, a significant minority of patients will develop some degree of respiratory insufficiency requiring hospitalization. In case of failure of conventional oxygen therapy, the method of choice in patients with respiratory insufficiency is ventilation with high-flow nasal cannula (HFNC). In order to reduce the dispersion of infectious aerosol during HFNC treatment, nasal cannula is often covered with a surgical mask in many hospitals. According to recent observations, the application of a surgical mask in these patients could also have a positive effect on oxygenation parameters without clinically relevant side effects. In the present set of case reports, we demonstrate this effective, simple and affordable way how to improve oxygenation in patients with COVID-19 and hypoxemic respiratory failure treated with HFNC.

Emergency Department Management of Severe Hypoxemic Respiratory Failure in Adults With COVID-19

Background

While emergency physicians are familiar with the management of hypoxemic respiratory failure, management of mechanical ventilation and advanced therapies for oxygenation in the emergency department have become essential during the coronavirus disease 2019 (COVID-19) pandemic.

Objective

We review the current evidence on hypoxemia in COVID-19 and place it in the context of known evidence-based management of hypoxemic respiratory failure in the emergency department.

Discussion

COVID-19 causes mortality primarily through the development of acute respiratory distress syndrome (ARDS), with hypoxemia arising from shunt, a mismatch of ventilation and perfusion. Management of patients developing ARDS should focus on mitigating derecruitment and avoiding volutrauma or barotrauma.

Conclusions

High flow nasal cannula and noninvasive positive pressure ventilation have a more limited role in COVID-19 because of the risk of aerosolization and minimal benefit in severe cases, but can be considered. Stable patients who can tolerate repositioning should be placed in a prone position while awake. Once intubated, patients should be managed with ventilation strategies appropriate for ARDS, including targeting lung-protective volumes and low pressures. Increasing positive end-expiratory pressure can be beneficial. Inhaled pulmonary vasodilators do not decrease mortality but may be given to improve refractory hypoxemia. Prone positioning of intubated patients is associated with a mortality reduction in ARDS and can be considered for patients with persistent hypoxemia. Neuromuscular blockade should also be administered in patients who remain dyssynchronous with the ventilator despite adequate sedation. Finally, patients with refractory severe hypoxemic respiratory failure in COVID-19 should be considered for venovenous extracorporeal membrane oxygenation.

Noninvasive Ventilation as a Weaning Strategy in Subjects with Acute Hypoxemic Respiratory Failure

BACKGROUND

Weaning through noninvasive ventilation (NIV) after early extubation may facilitate invasive ventilation withdrawal and reduce related complications in patients with hypercapnic respiratory failure. However, the effects of NIV weaning are uncertain in patients with acute hypoxemic respiratory failure (AHRF). We aimed to investigate whether NIV weaning could reduce hospital mortality and other outcomes compared with invasive weaning in subjects with hypoxemic AHRF.

METHODS

We searched medical literature databases for relevant articles published from inception to February 2019. Randomized controlled trials that adopted NIV as a weaning strategy compared with invasive weaning in hypoxemic AHRF were included. The primary outcome was hospital mortality. The secondary outcomes included ICU mortality, the ICU stay, weaning time, duration of ventilation, extubation failure, and adverse events.

RESULTS

Six relevant studies, which involved 718 subjects, were included. There was no significant effect of NIV weaning on hospital mortality compared with invasive weaning (risk ratio 0.94, 95% CI 0.65-1.36; P = .74), whereas there was a significant effect of NIV weaning on shortening the ICU stay (mean difference -3.95, 95% CI -6.49 to -1.40, P = .002) and on decreasing adverse events without affecting the weaning time (standardized MD -0.04, 95% CI -0.21 to 0.14; P = .68).

CONCLUSIONS

The strategy of NIV weaning did not decrease hospital mortality in subjects with hypoxemic AHRF, but it did shorten the ICU lengths of stay and reduce adverse events.

Initial Noninvasive Oxygenation Strategies in Subjects With De Novo Acute Hypoxemic Respiratory Failure

BACKGROUND

De novo hypoxemic respiratory failure is defined as significant hypoxemia in the absence of chronic lung disease such as COPD, and excluding respiratory failure occurring in the immediate postoperative or postextubation period. We aimed to evaluate the efficacy of various oxygenation strategies including noninvasive ventilation (NIV), high-flow nasal cannula (HFNC), and conventional oxygen therapy in patients with de novo hypoxemic respiratory failure.

METHODS

We performed electronic database searches of PubMed, Cochrane Library, and Embase from inception to December 2018 to include randomized controlled trials that compared various oxygenation strategies in cases of de novo hypoxemic respiratory failure occurring in adult subjects without a preexisting chronic lung disease and excluding respiratory failure in the immediate postoperative or postextubation periods. We performed a Bayesian network meta-analysis to calculate odds ratio (OR) and Bayesian 95% credible intervals (CrI).

RESULTS

16 studies were included, involving 2,180 subjects with a mean age of 61 ± 17 y (66% were male; 46% of the included subjects were treated with conventional oxygen, 27.8% were treated with NIV, and 25.8% were treated with HFNC). Compared to conventional oxygen, NIV was associated with reduced intubation rates (OR 0.42, 95% CrI 0.26-0.62) but no significant reduction in short-term (OR 0.73, 95% CrI 0.47-1.02) or long-term mortality (OR 0.60, 95% CrI 0.29-1.06). There was no significant difference between NIV and HFNC or between HFNC and conventional oxygen regarding all outcomes. In a sensitivity analysis, the results remained consistent after exclusion of studies that included subjects with respiratory failure secondary to cardiogenic pulmonary edema.

CONCLUSION

Among subjects with hypoxemic respiratory failure, NIV was associated with a significant reduction in intubation rates but not short- or long-term mortality when compared to conventional oxygen therapy. There was no significant difference between NIV and HFNC or between HFNC and conventional oxygen regarding all outcomes.

Tolerability and safety of awake prone positioning COVID-19 patients with severe hypoxemic respiratory failure

PURPOSE

Prone positioning of non-intubated patients with coronavirus disease (COVID-19) and hypoxemic respiratory failure may prevent intubation and improve outcomes. Nevertheless, there are limited data on its feasibility, safety, and physiologic effects. The objective of our study was to assess the tolerability and safety of awake prone positioning in COVID-19 patients with hypoxemic respiratory failure.

METHODS

This historical cohort study was performed across four hospitals in Calgary, Canada. Included patients had suspected COVID-19 and hypoxic respiratory failure requiring intensive care unit (ICU) consultation, and underwent awake prone positioning. The duration, frequency, tolerability, and adverse events from prone positioning were recorded. Respiratory parameters were assessed before, during, and after prone positioning. The primary outcome was the tolerability and safety of prone positioning.

RESULTS

Seventeen patients (n = 12 ICU, n = 5 hospital ward) were included between April and May 2020. The median (range) number of prone positioning days was 1 (1-7) and the median number of sessions was 2 (1-6) per day. The duration of prone positioning was 75 (30-480) min, and the peripheral oxygen saturation was 91% (84-95) supine and 98% (92-100) prone. Limitations to prone position duration were pain/general discomfort (47%) and delirium (6%); 47% of patients had no limitations. Seven patients (41%) required intubation and two patients (12%) died.

CONCLUSIONS

In a small sample, prone positioning non-intubated COVID-19 patients with severe hypoxemia was safe; however, many patients did not tolerate prolonged durations. Although patients had improved oxygenation and respiratory rate in the prone position, many still required intubation. Future studies are required to determine methods to improve the tolerability of awake prone positioning and whether there is an impact on clinical outcomes.

Standardized Management for Hypoxemic Respiratory Failure and ARDS: Systematic Review and Meta-analysis

BACKGROUND

Treatment of hypoxemic respiratory failure (HRF) and ARDS is complex. Standardized management of HRF and ARDS may improve adherence to evidence-informed practice and improve outcomes.

RESEARCH QUESTION

What is the effect of standardized treatment compared with usual care on survival of patients with HRF and ARDS?

STUDY DESIGN AND METHODS

MEDLINE, EMBASE, Cochrane, CINAHL, Scopus, and Web-of-Science were searched (inception to 2018). Included studies were randomized clinical trials or quasi-experimental studies that examined the effect of standardized treatment (care-protocol, care-pathway, or bundle) compared with usual treatment among mechanically ventilated adult patients admitted to an ICU with HRF or ARDS. Study characteristics, pathway components, and patient outcomes were abstracted independently by two reviewers.

RESULTS

From 15,932 unique citations, 14 studies were included in the systematic review (three randomized clinical trials and 11 quasi-experimental studies). Twelve studies (including 5,767 patients) were included in the meta-analysis. Standardized management of HRF was associated with a 23% relative reduction in mortality (relative risk, 0.77; 95% CI, 0.65-0.91; I², 70%; P = .002). In studies targeting patients with ARDS (n = 8), a 21% pooled mortality reduction was observed (relative risk, 0.79; 95% CI, 0.71-0.88; I², 3.1%). Standardized management was associated with increased 28-day ventilator-free days (weighted mean difference, 3.48 days; 95% CI, 2.43-4.54 days; P < .001). Standardized management was also associated with a reduction in tidal volume (weighted mean difference, -1.80 mL/kg predicted body weight; 95% CI, -2.80 to -0.80 mL/kg predicted body weight; P < .001). Meta-regression demonstrated that the reduction in mortality was associated with provision of lower tidal volume (P = .045).

INTERPRETATION

When compared with usual treatment, standardized treatment of patients with HRF and ARDS is associated with increased ventilator-free days, lower tidal volume ventilation, and lower mortality. ICUs should consider the use of standardized treatment to improve the processes and outcomes of care for patients with HRF and ARDS.

CLINICAL TRIAL REGISTRATION

PROSPERO; No.: CRD42019099921; URL: www.crd.york.ac.uk/prospero/.

The Role of Interleukin-6 Inhibitors in the Treatment of COVID-19 Infections: A Case Series

An outbreak of severe acute respiratory distress syndrome coronavirus 2 (SARS-CoV-2) infection started in December 2019 in China that resulted in a global health emergency. The World Health Organization later named the disease as coronavirus disease 2019 (COVID-19). Currently, there is no effective treatment available and the data are evolving through continuous clinical trials and ongoing research. Severe infections present with hypoxemic respiratory failure from acute respiratory distress syndrome as one of the major complications. We report two cases of COVID-19 patients who initially presented with moderate to severe symptoms. Later, their clinical course worsened despite ongoing treatment with multiple medications such as hydroxychloroquine and azithromycin until they were started on tocilizumab. Within a short period after they were administered tocilizumab, their oxygen saturation improved and other inflammatory markers such as D-dimer levels, lactate dehydrogenase, and ferritin levels decreased. There is an increase in the amount of research citing the role of various cytokines in the pathophysiology of COVID-19. Targeting the inflammatory mediators in the pathogenesis, especially interleukin-6 pathway inhibitors, would improve overall morbidity and mortality, thus decreasing the burden on healthcare systems.

High flow oxygen therapy in intensive care and anaesthesiology

Na podstawie przeglądu aktualnego piśmiennictwa przedstawiono zasady i praktyczne efekty zastosowania wysokoprzepływowego leczenia tlenem (WLT) wśród chorych intensywnej terapii i poddanych zabiegom operacyjnym. Rezultaty stosowania WLT wybiegają poza uzyskanie stabilnego i kontrolowanego stężenia tlenu w powietrzu oddechowym. Dodatkowe efekty związane są z uzyskiwaniem dodatnich ciśnień w fazie wydechu, zjawiska wypłukiwania CO2 i czynnościowego zmniejszania przestrzeni martwej, wzrostu końcowo - wydechowej objętości płuc w wyniku ograniczania mikro-niedodmy i poprawy dystrybucji objętości oddechowej. W wyniku optymalnego nawilżania i ogrzewania mieszaniny wdechowej dochodzi do zmniejszenia oporów wentylacji i pracy oddychania. Opisane efekty WLT skłaniają do prób jej wykorzystywania nie tylko jako narzędzia tlenoterapii biernej, ale również jako urządzenia alternatywnego dla wentylacji nieinwazyjnej lub wczesnej intubacji. Zakres zastosowań ocenionych w piśmiennictwie dotyczy ostrej hypoksemicznej niewydolności oddechowej, wstępnej fazy ARDS, POChP, okresu okołooperacyjnego oraz zastosowań podczas procesów diagnostycznych (gastroskopia, bronchoskopia). Szczególną formą WLT jest poddawana aktualnie ocenie adaptacja metody dla chorych z tracheostomią, usprawniająca głównie procesy nawilżania mieszaniny oddechowej. WLT wymaga dalszych ocen w dużych, randomizowanych badaniach, jednak dotychczasowe efekty stosowania są zachęcające.

Amiodarone-induced Hemoptysis: A Rare Presentation of Amiodarone-induced Pulmonary Toxicity Occurs at a Low Dose

Amiodarone-induced pulmonary toxicity (APT) is one of the most feared and underappreciated adverse effects of this commonly prescribed antiarrhythmic. APT has a variable presentation, among the rarest of these is amiodarone-induced diffuse alveolar hemorrhage with hemoptysis. Though previous cases confirmed with biopsy averaged a dose of 570 mg PO daily, APT can occur at any dose. Previous literature has suggested the importance of cumulative exposure to amiodarone rather than the patient's actual dose. The presented case describes amiodarone-induced hemoptysis occurring at a dose of 200 mg PO daily for five years. Additionally described is the treatment regimen which managed a patient with metabolic syndrome and elevated A1c while addressing the recommended treatment of extended high-dose steroids for APT with complicated respiratory status. To the best of the authors' knowledge, only two biopsied cases have been described at a dose this low. Furthermore, this case describes a more typical timeline for APT than those two cases.

Early Use of Inhaled Nitric Oxide in Preterm Infants: Is there a Rationale for Selective Approach?

Background Inhaled nitric oxide (iNO) is being increasingly used in preterm infants < 34 weeks with hypoxemic respiratory failure (HRF) and/or pulmonary hypertension (PH). Objective To evaluate the risk factors, survival characteristics, and lung histopathology in preterm infants with PH/HRF. Methods Retrospective chart review was conducted to determine characteristics of 93 preterm infants treated with iNO in the first 28 days and compared with 930 matched controls. Factors associated with survival with preterm HRF and smooth muscle actin from nine autopsies were evaluated. Results Preterm neonates treated with iNO had a higher incidence of preterm prolonged rupture of membrane (pPROM ≥ 18 hours), oligohydramnios and delivered by C-section. In infants treated with iNO, antenatal steroids (odds ratio [OR],3.7; confidence interval [CI], 1.2-11.3; p = 0.02), pPROM (OR, 1.001; CI, 1.0-1.004; p = 0.3), and oxygenation response to iNO (OR, 3.7; CI, 1.08-13.1; p = 0.037) were associated with survival. Thirteen infants with all three characteristics had 100% (13/13) survival without severe intraventricular hemorrhage (IVH)/periventricular leukomalacia (PVL) compared with 48% survival (12/25, p = 0.004) and 16% severe IVH/PVL without any of these factors. Severity of HRF correlated with increased smooth muscle in pulmonary vasculature. Conclusion Preterm infants with HRF exposed to antenatal steroids and pPROM had improved oxygenation with iNO and survival without severe IVH/PVL. Precisely targeting this subset may be beneficial in future trials of iNO.

Is oxygen saturation variable of simplified pulmonary embolism severity index reliable for identification of patients, suitable for outpatient treatment

INTRODUCTION

The pulmonary embolism severity index (PESI) or simplified version (sPESI) are widely validated risk scores for the identification of eligible patients for outpatient treatment. Saturation is one of these criteria. For this metric, saturation of 90% or greater is assigned zero points. However, 90% saturation does not always exclude hypoxemic respiratory failure.

OBJECTIVE

The aims of this study were first was to define corresponding partial arterial oxygen pressure (PaO₂ ) values according to saturation in pulmonary embolism (PE) patients, and the second was to define a target saturation that can exclude hypoxemic respiratory failure and enable secure discharge of PE patients from emergency departments.

METHODS

This is a retrospective study. To determine the optimal saturation value by which to detect hypoxemic respiratory failure, we generated receiver operating characteristic (ROC) curves and calculated the negative predictive value.

RESULTS

Total of 65 patients were included in this study. Mean PaO₂ levels from SaO₂ 89% to SaO₂ 93% were 52.8, 57.1, 57.3, 61, and 63.8 mmHg, respectively. ROC curve analysis revealed SaO₂ level of 91.5% to be optimal target saturation for excluding respiratory failure with 84.6% specificity and 89.7% sensitivity; area under the curve was 0.885 (95% CI 0.796-0.975). The negative predictive value was 80% for SaO₂ level of 92%.

CONCLUSION

Patients with PE may be in respiratory failure despite an oxyhemoglobin saturation of ≥90%. Although saturation is likely more important than precise PaO₂ in tissue oxygenation, clinicians should be aware of the physiological effects of hypoxemia and take this into account before making outpatient treatment decisions.

Successful Treatment of a Neonate with Idiopathic Persistent Pulmonary Hypertension with Inhaled Nitric Oxide via Nasal Cannula without Mechanical Ventilation

We report a case study of a term neonate presenting with oxygen desaturation without respiratory distress or acidosis, despite receiving 100% oxygen through a nasal cannula. Echocardiogram showed evidence of persistent pulmonary hypertension of the newborn (PPHN). She was successfully treated with inhaled nitric oxide (iNO) via nasal cannula without requiring mechanical ventilation. In a term neonate with idiopathic PPHN with adequate respiratory drive without any parenchymal lung disease, noninvasive methods of iNO delivery may treat the condition without the complications associated with mechanical ventilation.