Non-invasive positive pressure ventilation versus endotracheal intubation in treatment of COVID-19 patients requiring ventilatory support

Oscillometry Longitudinal Data on COVID-19 Acute Respiratory Syndrome Treated with Non-Invasive Respiratory Support

Background: Oscillometry allows for the non-invasive measurements of lung mechanics. In COVID-19 ARDS patients treated with Non-Invasive Oxygen Support (NI-OS), we aimed to (1) observe lung mechanics at the patients' admission and their subsequent changes, (2) compare lung mechanics with clinical and imaging data, and (3) evaluate whether lung mechanics helps to predict clinical outcomes. Methods: We retrospectively analyzed the data from 37 consecutive patients with moderate-severe COVID-19 ARDS. Oscillometry was performed on their 1st, 4th, and 7th day of hospitalization. Resistance (R5), reactance (X5), within-breath reactance changes (ΔX5), and the frequency dependence of the resistance (R5-R19) were considered. Twenty-seven patients underwent computed tomographic pulmonary angiography (CTPA): collapsed, poorly aerated, and normally inflated areas were quantified. Adverse outcomes were defined as intubation or death. Results: Thirty-two patients were included in this study. At the first measurement, only 44% of them had an abnormal R5 or X5. In total, 23 patients had measurements performed on their 3rd day and 7 on their 7th day of hospitalization. In general, their R5, R5-R19, and ΔX decreased with time, while their X5 increased. Collapsed areas on the CTPA correlated with the X5 z-score (ρ = -0.38; p = 0.046), while poorly aerated areas did not. Seven patients had adverse outcomes but did not present different oscillometry parameters on their 1st day of hospitalization. Conclusions: Our study confirms the feasibility of oscillometry in critically ill patients with COVID-19 pneumonia undergoing NI-OS. The X5 z-scores indicates collapsed but not poorly aerated lung areas in COVID-19 pneumonia. Our data, which show a severe impairment of gas exchange despite normal reactance in most patients with COVID-19 ARDS, support the hypothesis of a composite COVID-19 ARDS physiopathology.

A Retrospective Analysis of Ventilatory Strategy Comparing Non-invasive Ventilation (NIV) With Invasive Ventilation in Patients Admitted With Severe COVID-19 Pneumonia

Background The second wave of the COVID-19 pandemic in India saw a sudden upsurge of critically ill patients getting admitted to the ICU. The guidance for respiratory support was unclear in the early phase. But later reports showed lower mortality with non-invasive ventilation (NIV) than with intubation. The aim of this study was to assess the end result of initial methods of ventilation in COVID-19 patients. Methodology Patients admitted to ICU with COVID-19 were categorized as group 1 (IPPV-intubated within 24 hrs of admission), group 2 (NIV -NIV only), group 3 (NIV+ IPPV-intubated after 24 hrs), and group 4 (NRBM - Non-Rebreathing Mask only). All causes in the hospital or 30-day mortality, length of stay in ICU, and incidence of pneumothorax were compared between groups. Logistic regression analysis was done to determine the odds of mortality. Results The overall mortality rate among patients admitted to tertiary care centers was 15% and the rate among patients in ICU was 54.07%. Patients in group 1 and group 3 had significantly high mortality rates of 90.47% and 93.75%, respectively, as compared to 51.28% in group 2 patients. The odds of mortality were high in group 3 (OR 29.57, 95% CI 4.51 and 193.52) and group 1 (OR 8.01, 95% CI 1.35 and 47.48). Conclusion In a resource-limited setting, the use of NIV is associated with higher survival in COVID-19 patients. The prognosis of patients who are intubated early or after a trial of NIV is the same with increased odds of mortality.

Does the intubation timeline affect the in-hospital mortality of COVID-19 patients? A retrospective cohort study

Background

Effective strategies for managing coronavirus disease 19 (COVID-19) patients suffering from acute respiratory distress are constantly evolving. The timeline and threshold for transitioning from non-invasive ventilation to intermittent mandatory ventilation in critical cases who develop COVID-19-related respiratory distress are undetermined. The present research intends to investigate if emergency room intubations in COVID-19 patients affect mortality.

Methods

Between January 1, 2021 and June 30, 2021, we retrospectively reviewed chart analysis on all patients with confirmed positive COVID-19 screening and who underwent endotracheal intubation. Depending on when the intubation was performed; early in the emergency room or delayed outside the emergency room, patients were separated into two cohorts. In addition to comorbid clinical manifestations, the quick sequential organ failure assessment (qSOFA) score, and in-hospital mortality were all recorded as demographic and clinical information.

Results

Fifty-eight of the 224 corona-positive patients who underwent intubation had their intubations performed in the emergency room. Age, sex, alcohol use, and smoking status did not significantly differ between the two categories at the baseline. The mean qSOFA score was higher in the early intubation cohort (3.5; p < 0.000) along with more underlying comorbidities (3.0; p < 0.000). When compared to the late intubation cohort (45.78%), patients treated with early intubation had a significantly greater death rate (67.24%).

Conclusion

In summary, we discovered that patients who underwent intubation in the emergency units exhibited a high quick SOFA score as well as maximum co-morbid conditions than patients intubated somewhere else in the hospital. The findings of our investigation imply that intubating patients too early might be risky.

Prediction of Noninvasive Ventilation Failure in COVID-19 Patients: When Shall We Stop?

INTRODUCTION

In coronavirus disease 2019 (COVID-19), there are no tools available for the difficult task of recognizing which patients do not benefit from maintaining respiratory support, such as noninvasive ventilation (NIV). Identifying treatment failure is crucial to provide the best possible care and optimizing resources. Therefore, this study aimed to build a model that predicts NIV failure in patients who did not progress to invasive mechanical ventilation (IMV).

METHODS

This retrospective observational study included critical COVID-19 patients treated with NIV who did not progress to IMV. Patients were admitted to a Portuguese tertiary hospital between October 1, 2020, and March 31, 2021. The outcome of interest was NIV failure, defined as COVID-19-related in-hospital death. A binary logistic regression was performed, where the outcome (mortality) was the dependent variable. Using the independent variables of the logistic regression a decision-tree classification model was implemented.

RESULTS

The study sample, composed of 103 patients, had a mean age of 66.3 years (SD=14.9), of which 38.8% (40 patients) were female. Most patients (82.5%) were autonomous for basic activities of daily living. The prediction model was statistically significant with an area under the curve of 0.994 and a precision of 0.950. Higher age, a higher number of days with increases in the fraction of inspired oxygen (FiO₂), a higher number of days of maximum expiratory positive airway pressure, a lower number of days on NIV, and a lower number of days from disease onset to hospital admission were, with statistical significance, associated with increased odds of death. A decision-tree classification model was then obtained to achieve the best combination of variables to predict the outcome of interest.

CONCLUSIONS

This study presents a model to predict death in COVID-19 patients treated with NIV in patients who did not progress to IMV, based on easily applicable variables that mainly reflect patients' evolution during hospitalization. Along with the decision-tree classification model, these original findings may help clinicians define the best therapeutical approach to each patient, prioritizing life-comforting measures when adequate, and optimizing resources, which is crucial within limited or overloaded healthcare systems. Further research is needed on this subject of treatment failure, not only to understand if these results are reproducible but also, in a broader sense, helping to fill this gap in modern medicine guidelines.

Noninvasive Respiratory Assist Devices in the Management of COVID-19-related Hypoxic Respiratory Failure: Pune ISCCM COVID-19 ARDS Study Consortium (PICASo)

Objective

To determine whether high-flow nasal oxygen (HFNO) or noninvasive ventilator (NIV) can avoid invasive mechanical ventilation (IMV) in COVID-19-related acute respiratory distress syndrome (ADRS), and the outcome predictors of these modalities.

Design

Multicenter retrospective study conducted in 12 ICUs in Pune, India.

Patients

Patients with COVID-19 pneumonia who had PaO₂/FiO₂ ratio <150 and were treated with HFNO and/or NIV.

Intervention

HFNO and/or NIV.

Measurements

The primary outcome was to assess the need of IMV. Secondary outcomes were death at Day 28 and mortality rates in different treatment groups.

Main results

Among 1,201 patients who met the inclusion criteria, 35.9% (431/1,201) were treated successfully with HFNO and/or NIV and did not require IMV. About 59.5% (714/1,201) patients needed IMV for the failure of HFNO and/or NIV. About 48.3, 61.6, and 63.6% of patients who were treated with HFNO, NIV, or both, respectively, needed IMV. The need of IMV was significantly lower in the HFNO group (p <0.001). The 28-day mortality was 44.9, 59.9, and 59.6% in the patients treated with HFNO, NIV, or both, respectively (p <0.001). On multivariate regression analysis, presence of any comorbidity, SpO₂ <90%, and presence of nonrespiratory organ dysfunction were independent and significant determinants of mortality (p <0.05).

Conclusions

During COVID-19 pandemic surge, HFNO and/or NIV could successfully avoid IMV in 35.5% individuals with PO₂/FiO₂ ratio <150. Those who needed IMV due to failure of HFNO or NIV had high (87.5%) mortality.

How to cite this article

Jog S, Zirpe K, Dixit S, Godavarthy P, Shahane M, Kadapatti K, et al. Noninvasive Respiratory Assist Devices in the Management of COVID-19-related Hypoxic Respiratory Failure: Pune ISCCM COVID-19 ARDS Study Consortium (PICASo). Indian J Crit Care Med 2022;26(7):791-797.

Extension of Non-invasive Ventilation Capabilities of MASI for the Care of Patients Affected by COVID-19

The MASI mechanical ventilator was developed in a state of emergency to meet the demand for ventilators caused by COVID-19. Although it has obtained positive results in its use with patients in intensive care units, not having an optimal quality non-invasive ventilation (NIV) modality prevents it from being used in the early treatment of patients, which has been shown to prevent admission to the ICU and reduce mortality. Therefore, the following study focuses on evaluating MASI's ability to provide NIV using different accessories in order to compare their performance and determine which one would work best with MASI, and under which conditions. To do this, the high-flow nasal cannula, facial mask, and ventilation helmet accessories were tested under different pressure parameter settings. The data was collected using a gas flow analyzer. After that, a statistical analysis of the results was carried out, which showed that the face mask is the best accessory to use for NIV with MASI, and that it performs with optimal accuracy and precision when the peak inspiratory pressure is set at a value lower than 25 cmH20. Clinical Relevance- This study presents an optimization of the non-invasive ventilation (NIV) modality of the MASI me-chanical ventilator by evaluating its performance with different accessories.

Predictors of Noninvasive Respiratory Support Failure in COVID-19 Patients: A Prospective Observational Study

Background and Objective: Respiratory assistance tactic that is best for COVID-19-associated acute hypoxemic respiratory failure (AHRF) individuals has yet to be determined. Patients with AHRF may benefit from the use of a high-flow nasal cannula (HFNC) and non-invasive ventilation (NIV). The goals of this prospective observational research were to estimate predictive factors for HFNC and NIV failure in COVID-19-related AHRF subjects. Materials and Methods: The research enlisted the participation of 124 patients. A stepwise treatment approach was used. HFNC and NIV were used on 124 (100%) and 64 (51.6%) patients, respectively. Thirty (24.2%) of 124 patients were intubated and received invasive mechanical ventilation. Results: 85 (68.5%) patients were managed successfully. Patients who required NIV exhibited a higher prevalence of treatment failure (70.3% vs. 51.6%, p = 0.019) and had higher mortality (59.4% vs. 31.5%, p = 0.001) than patients who received HFNC. Using logistic regression, the respiratory rate oxygenation (ROX) index at 24 h (odds ratio (OR) = 0.74, p = 0.018) and the Charlson Comorbidity Index (CCI) (OR = 1.60, p = 0.003) were found to be predictors of HFNC efficacy. It was the ROX index at 24 h and the CCI optimum cut-off values for HFNC outcome that were 6.1 (area under the curve (AUC) = 0.73) and 2.5 (AUC = 0.68), respectively. Serum ferritin level (OR = 0.23, p = 0.041) and lymphocyte count (OR = 1.03, p = 0.01) were confirmed as predictors of NIV failure. Serum ferritin level at a cut-off value of 456.2 ng/mL (AUC = 0.67) and lymphocyte count lower than 0.70 per mm³, (AUC = 0.70) were associated with NIV failure with 70.5% sensitivity, 68.7% specificity and sensitivity of 84.1%, specificity of 56.2%, respectively. Conclusion: The ROX index at 24 h, CCI, as well as serum ferritin level, and lymphocyte count can be used as markers for HFNC and NIV failure, respectively, in SARS-CoV-2-induced AHRF patients.

Endotracheal intubation rate is lower in critically-ill SARS-CoV-2 patients requiring high-flow nasal oxygen receiving additional face-mask noninvasive ventilation: a retrospective bicentric cohort with propensity score analysis

BACKGROUND

SARS-CoV-2 pneumonia is responsible for unprecedented numbers of acute respiratory failure requiring invasive mechanical ventilation (IMV). This work aimed to assess whether adding face-mask noninvasive ventilation (NIV) to high-flow nasal oxygen (HFNO) was associated with a reduced need for endotracheal intubation.

METHODS

This retrospective cohort study was conducted from July 2020 to January 2021 in two tertiary care intensive care units (ICUs) in Paris, France. Patients admitted for laboratory confirmed SARS-CoV-2 infection with acute hypoxemic respiratory failure requiring HFNO with or without NIV were included. The primary outcome was the rate of endotracheal intubation. Secondary outcomes included day-28 mortality, day-28 respiratory support and IMV free days, ICU and hospital length-of-stay. Sensitivity analyses with both propensity score matching and overlap weighting were used.

RESULTS

128 patients were included, 88 (69%) received HFNO alone and 40 (31%) received additional NIV. Additional NIV was associated with a reduced rate of endotracheal intubation in multivariate analysis (53 (60%) vs 15 (38%), HR=0.46 (95%CI, 0.23-0.95), p=0.04). Sensitivity analyses by propensity score matching (HR=0.45 (95%IC, 0.24-0.84), p=0.01) and overlap weighting (HR=0.52 (95% CI, 0.28-0.94), p=0.03) were consistent. Day-28 mortality was 25 (28%) in the HFNO group and 8 (20%) in the NIV group (HR=0.75 (95%CI, 0.15-3.82), p=0.72). NIV was associated with higher IMV free days (20 (0-28) vs 28 (14-28), p=0.015). All sensitivity analyses were consistent regarding secondary outcomes.

CONCLUSION

Need for endotracheal intubation was lower in critically-ill SARS-CoV-2 patients receiving face-mask noninvasive mechanical ventilation in addition to high-flow oxygen therapy.

Non-invasive respiratory support in the management of acute COVID-19 pneumonia: considerations for clinical practice and priorities for research

Non-invasive respiratory support (NIRS) has increasingly been used in the management of COVID-19-associated acute respiratory failure, but questions remain about the utility, safety, and outcome benefit of NIRS strategies. We identified two randomised controlled trials and 83 observational studies, compromising 13 931 patients, that examined the effects of NIRS modalities-high-flow nasal oxygen, continuous positive airway pressure, and bilevel positive airway pressure-on patients with COVID-19. Of 5120 patients who were candidates for full treatment escalation, 1880 (37%) progressed to invasive mechanical ventilation and 3658 of 4669 (78%) survived to study end. Survival was 30% among the 1050 patients for whom NIRS was the stated ceiling of treatment. The two randomised controlled trials indicate superiority of non-invasive ventilation over high-flow nasal oxygen in reducing the need for intubation. Reported complication rates were low. Overall, the studies indicate that NIRS in patients with COVID-19 is safe, improves resource utilisation, and might be associated with better outcomes. To guide clinical decision making, prospective, randomised studies are needed to address timing of intervention, optimal use of NIRS modalities-alone or in combination-and validation of tools such as oxygenation indices, response to a trial of NIRS, and inflammatory markers as predictors of treatment success.

Clinical Outcomes of Early Versus Late Intubation in COVID-19 Patients

Background The implications of intubation timing in COVID-19 patients remain highly debatable due to the scarcity of available evidence. Objectives Our study aims to assess the clinical characteristics and outcomes of COVID-19 patients undergoing early intubation compared to those undergoing late intubation. Methods This is a single-center retrospective study of adult COVID-19 patients admitted between March 1, 2020 and January 10, 2021. Early intubation was defined as intubation within 24 hours of a) hospital admission; b) respiratory status deterioration requiring FiO₂ 60% and higher; or c) moderate/severe acute respiratory distress syndrome (ARDS) diagnosis. Results Among the 128 COVID-19 patients included, 66.4% required early intubation, and 33.6% required late intubation. The 28-day all-cause mortality and other outcomes of mechanical ventilation duration, hospital and ICU length of stay were equal regardless of intubation timing. Clinical characteristics, inflammatory markers, COVID-19 therapies, PaO₂/FiO₂ ratio, and pH were comparable for both groups. Better lung compliance was observed during early intubation than late intubation based on plateau (mean 21.3 vs. 25.5 cmH₂O; P < 0.01) and peak pressure (mean 24.1 vs. 27.4 cmH₂O; P = 0.04). Conclusions In critically ill COVID-19 patients, the timing of intubation was not significantly associated with poor clinical outcomes in the setting of matching clinical characteristics. More research is needed to determine which subset of patients may benefit from intubation and the predictors for optimal intubation timing.

Noninvasive Ventilation in the Management of Respiratory Failure Due to COVID-19 Infection: Experience From a Resource-Limited Setting

OBJECTIVE

To study the role of noninvasive ventilation (NIV) in Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV2) related acute respiratory failure (C-ARF).

PATIENTS AND METHODS

Patients with C-ARF managed on NIV were categorized as NIV success or failure (death or intubation). Factors associated with failure were explored using regression analysis and expressed as odds ratio (OR) with 95% CI.

RESULTS

Between April 1, 2020, and September 15, 2020, a total of 286 patients with a mean ± SD age of 53.1±11.6 years and Acute Physiology and Chronic Health Evaluation II score of 11.1±5.5 were initiated on NIV. Of the 182 patients (63.6%) successfully managed on NIV alone, 118 had moderate or severe acute respiratory distress syndrome. When compared with NIV success, NIV failure was associated with lower admission PaO₂ to fraction of inspired oxygen ratio (P<.001) and higher respiratory rate (P<.001). On penalized logistic regression analysis, NIV failure was associated with higher Acute Physiology and Chronic Health Evaluation II score (OR, 1.12; 95% CI, 1.01 to 1.24), severe acute respiratory distress syndrome (OR, 3.99; 95% CI, 1.24 to 12.9), D-dimer level of 1000 ng/mL DDU (to convert to mg/L, divide by 1000) or greater (OR, 2.60; 95% CI, 1.16 to 5.87), need for inotropes or dialysis (OR, 12.7; 95% CI, 4.3 to 37.7), and nosocomial infections (OR, 13.6; 95% CI, 4.06 to 45.9). Overall mortality was 30.1% (86/286). In patients requiring intubation, time to intubation was longer in nonsurvivors than survivors (median, 5; interquartile range, 3-8 vs 3; interquartile range, 2-3 days; P<.001).

CONCLUSION

Noninvasive ventilation can be used successfully in C-ARF. Illness severity and need for non-respiratory organ support predict NIV failure.

Differences between the first and the second wave of critically ill COVID-19 patients admitted to the intensive care units

Background

To compare the demographic characteristics and prognosis of patients admitted to the intensive care unit (ICU) for coronavirus disease 2019 (COVID-19) pneumonia during the first wave (March-July) versus those admitted during the second wave (August-December).

Methods

Prospective, observational, descriptive cohort-study including patients admitted to the ICU for COVID-19 pneumonia during the first wave (March-July 2020) or the second wave (August-December). The demographic characteristics, comorbidities, treatments, complications, and mortality in both pandemic waves were studied.

Results

A total of 72 patients were included: Twenty-six admitted during the first wave and 46 during the second wave. Men were predominant in both waves: 61.5% versus 73.9%. The most frequently associated comorbidities in both periods were: arterial hypertension 65.4% versus 65.2%, diabetes mellitus 46.2% versus 34.8% and overweight, measured as (body mass index), 29.13 ± 3.38 versus 28.98 ± 4.25. More patients received noninvasive mechanical ventilation prior to invasive ventilation during the second wave (P < 0.01); the incidence of atelectasis and bronchial obstruction were lower during the second wave (P < 0.01 and P = 0.055 respectively); no further differences were observed in the occurrence of other complications.

Conclusions

No significant differences were observed between the first and the second wave in the demographic characteristics or comorbidities of admitted patients. Blood hypertension, diabetes and overweight were remarkable risk factors. Improving our knowledge of the complications, these patients tend to develop was essential to reduce some of them, such as endotracheal tube obstruction or atelectasis, and to promote the use of noninvasive ventilation therapies.

Use of high-flow nasal cannula oxygen and risk factors for high-flow nasal cannula oxygen failure in critically-ill patients with COVID-19

BACKGROUND

High-flow nasal oxygen therapy (HFNC) may be an attractive first-line ventilatory support in COVID-19 patients. However, HNFC use for the management of COVID-19 patients and risk factors for HFNC failure remain to be determined.

METHODS

In this retrospective study, we included all consecutive COVID-19 patients admitted to our intensive care unit (ICU) in the first (Mars-May 2020) and second (August 2020- February 202) French pandemic waves. Patients with limitations for intubation were excluded. HFNC failure was defined as the need for intubation after ICU admission. The impact of HFNC use was analyzed in the whole cohort and after constructing a propensity score. Risk factors for HNFC failure were identified through a landmark time-dependent cause-specific Cox model. The ability of the 6-h ROX index to detect HFNC failure was assessed by generating receiver operating characteristic (ROC) curve.

RESULTS

200 patients were included: HFNC was used in 114(57%) patients, non-invasive ventilation in 25(12%) patients and 145(72%) patients were intubated with a median delay of 0 (0-2) days after ICU admission. Overall, 78(68%) patients had HFNC failure. Patients with HFNC failure had a higher ICU mortality rate (34 vs. 11%, p = 0.02) than those without. At landmark time of 48 and 72 h, SAPS-2 score, extent of CT-Scan abnormalities > 75% and HFNC duration (cause specific hazard ratio (CSH) = 0.11, 95% CI (0.04-0.28), per + 1 day, p < 0.001 at 48 h and CSH = 0.06, 95% CI (0.02-0.23), per + 1 day, p < 0.001 at 72 h) were associated with HFNC failure. The 6-h ROX index was lower in patients with HFNC failure but could not reliably predicted HFNC failure with an area under ROC curve of 0.65 (95% CI(0.52-0.78), p = 0.02). In the matched cohort, HFNC use was associated with a lower risk of intubation (CSH = 0.32, 95% CI (0.19-0.57), p < 0.001).

CONCLUSIONS

In critically-ill COVID-19 patients, while HFNC use as first-line ventilatory support was associated with a lower risk of intubation, more than half of patients had HFNC failure. Risk factors for HFNC failure were SAPS-2 score and extent of CT-Scan abnormalities > 75%. The risk of HFNC failure could not be predicted by the 6-h ROX index but decreased after a 48-h HFNC duration.

Invasive Airway "Intubation" in COVID-19 Patients; Statistics, Causes, and Recommendations: A Review Article

CONTEXT

Severe coronavirus disease 2019 (COVID-19) can induce acute respiratory distress, which is characterized by tachypnea, hypoxia, and dyspnea. Intubation and mechanical ventilation are strategic treatments for COVID-19 distress or hypoxia.

METHODS

We searched PubMed, Embase, and Scopus databases to identify relevant randomized control trials, observational studies, and case series published from April 1, 2021.

RESULTS

24 studies were included in this review. Studies had been conducted in the USA, China, Spain, South Korea, Italy, Iran, and Brazil. Most patients had been intubated in the intensive care unit. Rapid sequence induction had been mostly used for intubation. ROX index can be utilized as the predictor of the necessity of intubation in COVID-19 patients. According to the studies, the rate of intubation was 5 to 88%. It was revealed that 1.4 - 44.5% of patients might be extubated. Yet obesity and age (elderly) are the only risk factors of delayed or difficult extubation.

CONCLUSIONS

Acute respiratory distress in COVID-19 patients could require endotracheal intubation and mechanical ventilation. Severe respiratory distress, loss of consciousness, and hypoxia had been the most important reasons for intubation. Also, increased levels of C-reactive protein (CRP), ferritin, d-dimer, and lipase in combination with hypoxia are correlated with intubation. Old age, diabetes mellitus, respiratory rate, increased level of CRP, bicarbonate level, and oxygen saturation are the most valuable predictors of the need for mechanical ventilation. ICU admission mortality following intubation was found to be 15 to 36%. Awake-prone positioning in comparison with high-flow nasal oxygen therapy did not reduce the risk of intubation and mechanical ventilation. There was no association between intubation timing and mortality of the infected patients. Noninvasive ventilation may have survival benefits.

Non-invasive oxygenation strategies for respiratory failure with COVID-19: A concise narrative review of literature in pre and mid-COVID-19 era

The coronavirus disease 2019 (COVID-19) has spread globally and can cause a shortage of medical resources, in particular, mechanical ventilators. High-flow nasal cannula oxygen therapy (HFNC) and non-invasive positive pressure ventilation (NPPV) are frequently used for acute respiratory failure patients as alternatives to invasive mechanical ventilation. They are drawing attention because of a potential role to save mechanical ventilators. However, their effectiveness and risk of viral spread are unclear. The latest network meta-analysis of pre-COVID-19 trials reported that treatment with non-invasive oxygenation strategies was associated with improved survival when compared with conventional oxygen therapy. During the COVID-19 pandemic, a lot of clinical research on COVID-19 related acute respiratory failure has been reported. Several observational studies and small trials have suggested HFNC or NPPV as an alternative of standard oxygen therapy to manage COVID-19 related acute respiratory failure, provided that appropriate infection prevention is applied by health care workers to avoid risks of the virus transmission. Awake proning is an emerging strategy to optimise the management of patients with COVID-19 acute respiratory failure. However, the benefits of awake proning have yet to be assessed in properly designed clinical research. Although HFNC and NPPV are probably effective for acute respiratory failure, the safety data are mostly based on observational and experimental reports. As such, they should be implemented carefully if adequate personal protective equipment and negative pressure rooms are available.

Characteristics, outcomes and global trends of respiratory support in patients hospitalized with COVID-19 pneumonia: a scoping review

INTRODUCTION

To date, a shared international consensus on treatment of Coronavirus Disease 2019 (COVID-19) with invasive or non-invasive respiratory support is lacking. Patients' management and outcomes, especially in severe and critical cases, can vary depending on regional standard operating procedures and local guidance.

EVIDENCE ACQUISITION

Rapid review methodology was applied to include all the studies published on PubMed and Embase between December 15th 2019 and February 28th 2021, reporting in-hospital and respiratory support-related mortality in adult patients hospitalized with COVID-19 that underwent either continuous positive airway pressure (CPAP), non-invasive ventilation (NIV) or invasive mechanical ventilation (IMV). Only English language studies with ≥100 patients and reporting data on respiratory failure were included. Data on comorbidities, ventilatory parameters and hospital-related complications were registered.

EVIDENCE SYNTHESIS

Fifty-two studies (287359 patients - 57.5% males, mean age 64 years (range 24-98)) from 17 different countries were included in the final analysis. 33.3% of patients were hospitalized in intensive care units. 44.2% had hypertension, 26.1% had diabetes, and 7.1% a chronic respiratory disease. 55% of patients underwent respiratory support (36% IMV, 62% NIV and 2% CPAP). Without considering a study with the highest number of patients treated with NIV (n=96729), prevalence of NIV and CPAP use was 12.5% and 13.5% respectively. Globally, invasive and non-invasive approaches were heterogeneously applied. In-hospital mortality was 33.7%, and IMV-related mortality was 72.6% (range: 4.3%-99%). Specific mortality in patients treated with CPAP or NIV was available for 53% of studies, and was 29% (range: 7.2%-100%). The median length of hospital stay was 13 days (range: 6-63). The most frequent hospital-related complication was acute kidney injury being reported in up to 55.7% of enrolled patients.

CONCLUSIONS

Global employment of respiratory supports and related outcomes are very heterogeneous. The most frequent respiratory support in patients with COVID-19 pneumonia is IMV, while NIV and CPAP are less frequently and equally applied, the latter especially in Europe, while data on NIV/CPAP-related mortality is often under-reported. Integrated and comprehensive reporting is desirable and needed to construct evidence-based recommendations.

Severe covid-19 pneumonia: pathogenesis and clinical management

Severe covid-19 pneumonia has posed critical challenges for the research and medical communities. Older age, male sex, and comorbidities increase the risk for severe disease. For people hospitalized with covid-19, 15-30% will go on to develop covid-19 associated acute respiratory distress syndrome (CARDS). Autopsy studies of patients who died of severe SARS CoV-2 infection reveal presence of diffuse alveolar damage consistent with ARDS but with a higher thrombus burden in pulmonary capillaries. When used appropriately, high flow nasal cannula (HFNC) may allow CARDS patients to avoid intubation, and does not increase risk for disease transmission. During invasive mechanical ventilation, low tidal volume ventilation and positive end expiratory pressure (PEEP) titration to optimize oxygenation are recommended. Dexamethasone treatment improves mortality for the treatment of severe and critical covid-19, while remdesivir may have modest benefit in time to recovery in patients with severe disease but shows no statistically significant benefit in mortality or other clinical outcomes. Covid-19 survivors, especially patients with ARDS, are at high risk for long term physical and mental impairments, and an interdisciplinary approach is essential for critical illness recovery.