Efficacy of non-invasive and invasive respiratory management strategies in adult patients with acute hypoxaemic respiratory failure: a systematic review and network meta-analysis

Performance of helmet CPAP using different configurations: Turbine-driven ventilators vs Venturi devices

BACKGROUND

Traditionally, Venturi-based flow generators have been preferred over mechanical ventilators to provide continuous positive airway pressure (CPAP) through the helmet (h-CPAP). Recently, modern turbine-driven ventilators (TDVs) showed to be safe and effective in delivering h-CPAP. We aimed to compare the pressure stability during h-CPAP delivered by Venturi devices and TDVs and assess the impact of High Efficiency Particulate Air (HEPA) filters on their performance.

METHODS

We performed a bench study using an artificial lung simulator set in a restrictive respiratory condition, simulating two different levels of patient effort (high and low) with and without the interposition of the HEPA filter. We calculated the average of minimal (Pmin), maximal (Pmax) and mean (Pmean) airway pressure and the time product measured on the airway pressure curve (PTPinsp). We defined the pressure swing (Pswing) as Pmax - Pmin and pressure drop (Pdrop) as End Expiratory Pressure - Pmin.

RESULTS

Pswing across CPAP levels varied widely among all the tested devices. During "low effort", no difference in Pswing and Pdrop was found between Venturi devices and TDVs; during high effort, Pswing (p<0.001) and Pdrop (p<0.001) were significantly higher in TDVs compared to Venturi devices, but the PTPinsp was lower (1.50 SD 0.54 vs 1.67 SD 0.55, p<0.001). HEPA filter addition almost doubled Pswing and PTPinsp (p<0.001) but left unaltered the differences among Venturi and TDVs systems in favor of the latter (p<0.001).

CONCLUSIONS

TDVs performed better than Venturi systems in delivering a stable positive pressure level during h-CPAP in a bench setting.

Effect of High-Flow Nasal Cannula Oxygen Therapy on Hypoxemia in Patients After Esophagectomy

Background: Patients with esophageal cancer (EC) who have undergone esophagectomy are at risk of developing hypoxemia and encountering postoperative complications. It is essential to ascertain whether the high-flow nasal cannula (HFNC) therapy offers superior clinical efficacy compared to conventional oxygen therapy (COT). Methods: Clinical data from 80 patients who experienced hypoxemia subsequent to radical esophagectomy were retrospectively collected at our institution spanning January 2020 to December 2022. The whole cohort was divided into two groups: the HFNC group and the COT group. Following oxygen administration, we evaluated the variations in arterial blood gas parameters and infection indices within each group, in addition to scrutinizing the occurrence of postoperative pulmonary complications. Results: The HFNC group was associated with a better oxygenation index (F group=41.779, p < 0.001) and partial pressure of carbon dioxide (F group=16.760, p < 0.001) compared with the COT group. Moreover, there were statistically significant differences in the reduction of C-reactive protein (F group = 17.603, p < 0.001) and neutrophil count (F group = 4.395, p=0.039) in the HFNC group compared with the COT group after 3 days of oxygen therapy. Notably, patients treated with HFNC exhibited a markedly reduced risk of developing postoperative complications, especially pneumonia (p=0.039). Conclusion: HFNC outperformed COT in enhancing oxygenation and reducing carbon dioxide levels and infection indices among patients with hypoxemia after radical resection of EC and also lowered the risk of postoperative pneumonia.

Noninvasive oxygenation and ventilation strategies for viral acute respiratory failure: a comprehensive systematic review and meta-analysis

BACKGROUND

The COVID-19 pandemic has resulted in a critical shortage of respiratory ventilators, highlighting the urgent need to explore alternative treatment options for patients with acute respiratory distress syndrome (ARDS) caused by respiratory viruses, as an alternative to invasive mechanical ventilation (IMV) in future pandemics.

OBJECTIVES

The objective of this study was to assess the effectiveness of alternative noninvasive oxygenation and ventilation strategies in comparison to invasive mechanical ventilation (IMV) in patients with virus-induced acute respiratory failure (ARF). The primary outcome was the all-cause ICU mortality rate.

METHODS

A systematic review was conducted following the Cochrane guidelines and PRISMA reporting guidelines. The search encompassed databases such as Medline, Cochrane CENTRAL, and Embase to identify relevant indexed literature. Additionally, gray literature was included by consulting regulatory agencies. The included studies compared various oxygenation and ventilatory alternatives, such as high-flow nasal cannula (HFNC), continuous positive airway pressure (CPAP), or noninvasive mechanical ventilation (NIMV) with IMV. An exploratory meta-analysis was performed by calculating the risk ratio (RR) by random effects and meta-regression to explore possible sources of heterogeneity and to compare ventilatory alternatives against IMV to reduce mortality, length of stay (LOS) days in ICU, nosocomial infection, and barotrauma.

RESULTS

A total of forty-seven studies were included in this systematic review. NIMV had an RR of 0.70 (0.58-0.85), HFNC had an RR of 0.54 (0.42-0.71), and CPAP had an RR of 0.80 (0.71-0.90), with meta-regression models that reduced heterogeneity to 0%. For LOS days in ICU, NIMV had 0.38 (- 0.69: - 0.08) lower days and HFNC 0.29 (- 0.64: 0.06) lower days with meta-regression models that reduction heterogeneity to 0% for HFNC and 50% for NIMV. Not enough studies reported nosocomial infection or barotrauma to evaluate them in a meta-analysis. The overall quality of evidence, as assessed by GRADE evaluation, was determined to be from very low to medium certainty depending on the ventilatory strategy and outcome.

CONCLUSIONS

The findings of this systematic review support the use of alternative noninvasive oxygenation and ventilation strategies as viable alternatives to conventional respiratory ventilation for managing viral-induced ARF. Although it is essential to interpret these findings with caution given the overall low to medium certainty of the evidence, the integration of these modalities as part of the management strategies of these patients could help reduce the utilization of ICU beds, invasive ventilators, and costs in both developed and developing countries.

Comparison of non-invasive ventilation on bilevel pressure mode and CPAP in the treatment of COVID-19 related acute respiratory failure. A propensity score-matched analysis

OBJECTIVE

The purpose of this study was to analyze the differences in the effectiveness and complications of CPAP versus non-invasive ventilation on bilevel positive airway pressure (BiPAP) in the treatment of COVID-19 associated acute respiratory failure (ARF).

DESIGN

Retrospective observational study.

SETTING

ICU.

PATIENTS

All COVID-19 patients, admitted to an ICU between March 2020 and February 2023, who required CPAP or BiPAP were analyzed.

INTERVENTIONS

Use of CPAP or BiPAP in COVID-19 associated ARF.

MAIN VARIABLES OF INTEREST

Initial clinical variables, CPAP and BiPAP failure rate, complications, in-hospital mortality.

RESULTS

429 patients were analyzed, of whom 328 (76.5%) initially received CPAP and 101 (23.5%) BiPAP. Initial respiratory rate was 30 ± 8 in the CPAP group and 34 ± 9 in BiPAP (p < 0.001), while PaO2/FiO2 was 120 ± 26 and 111 ± 24 mmHg (p = 0.001), respectively. The most frequent complication related to the device was claustrophobia/discomfort, 23.2% in CPAP and 25.7% in BiPAP (p = 0.596), while the most frequent complications not related to the device were severe ARDS, 58.6% and 70.1% (p = 0.044), and hyperglycemia, 44.5% and 37.6%, respectively (p = 0.221). After adjusting by propensity score matched analysis, neither failure of the device (OR 1.37, CI 95% 0.72-2.62) nor in-hospital mortality (OR 1.57, CI 95% 0.73-3.42) differed between both groups.

CONCLUSIONS

Either non-invasive ventilatory device failure or mortality rate differed in patients initially treated with CPAP versus BiPAP.

A Meta-Analysis on the Efficacy of Noninvasive Positive Pressure Ventilation Combined With Pressure Support Ventilation in Treating Chronic Heart Failure

OBJECTIVE

To evaluate the clinical efficacy and safety of noninvasive positive pressure ventilation combined with pressure support ventilation (NPPV-PSV) in the treatment of chronic heart failure (CHF) through a meta-analysis.

METHODS

A systematic search was conducted using PubMed, Embase, Web of Science, Cochrane Library, CNKI and Wanfang databases to find randomized controlled trials and cohort studies on NPPV-PSV treatment for CHF. The period of search was set from inception until 2024. Eligible studies were included in a systematic review and meta-analysis.

RESULTS

A total of 8 studies with 568 patients were included in this meta-analysis. The meta-analysis revealed that compared with conventional treatment, NPPV-PSV treatment had significant advantages in several aspects: clinical efficacy rate (total effect Z = 5.10, OR = 3.12, 95% confidence interval (CI) [2.01, 4.83], p = 0.000), heart rate (HR) (total effect Z = 16.26, MD = -10.50, 95% CI [-11.76, -9.23], p = 0.000), respiratory rate (RR) (total effect Z = 16.50, MD = -6.44, 95% CI [-7.20, -5.67], p = 0.000) and oxygen saturation (total effect Z = 12.40, MD = 0.09, 95% CI [0.08, 0.11], p = 0.000).

CONCLUSION

Noninvasive positive pressure ventilation combined with PSV treatment significantly improves clinical symptoms, reduces HR and RR and increases oxygen saturation in patients with CHF, showing superior effects compared with conventional treatment.

Non-invasive respiratory support in elderly hospitalized patients

INTRODUCTION

The proportion of elderly people among hospitalized patients is rapidly growing. Between 7% to 25% of ICU patients are aged 85 and over and noninvasive respiratory support is often offered to avoid the risks of invasive mechanical ventilation or in patients with a 'do-not-intubate' order. However, while noninvasive respiratory support has been extensively studied in the general population, there is limited data available on its efficacy in elderly patients with ARF.

AREAS COVERED

PubMed/Medline, Web of Science, Scopus and Embase online databases were searched for studies that assessed clinical efficacy of high flow nasal cannula, continuous positive airway pressure and noninvasive ventilation in patients ≥ 65 years old with acute de novo ARF, showing that short to mid-term benefits provided by noninvasive respiratory support in elderly patients in terms of reduction of mechanical ventilation risk and mortality are similar to younger patients, if adjusted for the severity of comorbidities and respiratory failure.

EXPERT OPINION

Noninvasive support strategies can represent an effective opportunity in elderly patients with ARF, especially in patients too frail to undergo endotracheal intubation and in whom received or decided for a 'do not intubate' order. Indeed, noninvasive support has a different impact, depending on the setting.

Pulmonary benign metastasizing leiomyoma presenting as acute hypoxemic respiratory failure: a case report

Pulmonary benign metastasizing leiomyoma is an uncommon condition, predominantly affecting women of childbearing age with a history of uterine smooth muscle tumors and uterine leiomyoma surgery for uterine leiomyoma. The progression of PBML is often unpredictable and depends on the extent of lung involvement. Generally, most patients remain asymptomatic, but a minority may experience coughing, wheezing, or shortness of breath, which are frequently misdiagnosed as pneumonia. consequently, this presents significant challenges in both treatment and nursing care before diagnosis. This paper reports the case of a 35-year-old woman primarily diagnosed with acute hypoxic respiratory failure who was transferred from the emergency room to the intensive care unit. The initial computed tomography scan of the patient's lungs indicated diffuse interstitial pneumonia, but the sequencing of the alveolar lavage fluid pathogen macro did not detect any bacteria, fungi, or viruses. Moreover, the patient remained in a persistent hypoxic state before the definitive diagnosis. Therefore, our focus was on maintaining the airway patency of the patient, using prone ventilation, inhaling nitric oxide, monitoring electrical impedance tomography, and preventing ventilator-associated pneumonia to improve oxygenation, while awaiting immunohistochemical staining of the patient's biopsied lung tissue. This would help us clarify the diagnosis and treat it based on etiology. After meticulous treatment and nursing care, the patient was weaned off the ventilator after 26 days and transferred to the respiratory ward after 40 days. This case study may serve as a reference for clinical practice and assist patients suffering from PBML.

[Non-invasive Mechanical Ventilation in Acute Respiratory Failure. Clinical Practice Guidelines - on behalf of the German Society of Pneumology and Ventilatory Medicine]

The guideline update outlines the advantages as well as the limitations of NIV in the treatment of acute respiratory failure in daily clinical practice and in different indications.Non-invasive ventilation (NIV) has a high value in therapy of hypercapnic acute respiratory failure, as it significantly reduces the length of ICU stay and hospitalization as well as mortality.Patients with cardiopulmonary edema and acute respiratory failure should be treated with continuous positive airway pressure (CPAP) and oxygen in addition to necessary cardiological interventions. This should be done already prehospital and in the emergency department.In case of other forms of acute hypoxaemic respiratory failure with only mild or moderately disturbed gas exchange (PaO2/FiO2 > 150 mmHg) there is no significant advantage or disadvantage compared to high flow nasal oxygen (HFNO). In severe forms of ARDS NIV is associated with high rates of treatment failure and mortality, especially in cases with NIV-failure and delayed intubation.NIV should be used for preoxygenation before intubation. In patients at risk, NIV is recommended to reduce extubation failure. In the weaning process from invasive ventilation NIV essentially reduces the risk of reintubation in hypercapnic patients. NIV is regarded useful within palliative care for reduction of dyspnea and improving quality of life, but here in concurrence to HFNO, which is regarded as more comfortable. Meanwhile NIV is also recommended in prehospital setting, especially in hypercapnic respiratory failure and pulmonary edema.With appropriate monitoring in an intensive care unit NIV can also be successfully applied in pediatric patients with acute respiratory insufficiency.

Analysis of therapeutic effects on type II respiratory failure and impact on blood gas changes: high-flow nasal oxygen therapy vs. non-invasive positive pressure ventilation

OBJECTIVE

To evaluate the efficacy of high-flow nasal oxygen therapy (HFNO) vs. non-invasive positive pressure ventilation (NIPPV) in type II respiratory failure, and analyze their impact on blood gas parameters.

METHODS

A retrospective analysis of 110 cases of type II respiratory failure treated from April 2021 to March 2023 categorized patients into control (NIPPV, n=50) and observation (HFNO, n=60) groups. Both groups received comprehensive nursing interventions. Treatment outcomes, respiratory and hemodynamic parameters, blood gas parameters, and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores were compared before and 48 hours after treatment. Additionally, the complication rates and independent risk factors affecting prognosis were analyzed.

RESULTS

The observation group exhibited superior treatment efficacy compared to the control group (P=0.001). Both groups showed significant improvements in APACHE II scores and respiratory, hemodynamic, and blood gas parameters after treatment (P<0.001), with the observation group experiencing more pronounced improvements (P<0.001). The observation group also had a lower incidence of complications than the control group (P=0.013). Logistic regression identified PaCO2 and treatment protocol as independent risk factors affecting adverse outcomes (P<0.05).

CONCLUSION

HFNO demonstrates superior therapeutic efficacy in type II respiratory failure, significantly improving blood gas parameters with a high level of safety, supporting its clinical applicability.

Continuous positive airway pressure versus high-flow nasal cannula oxygen therapy for acute hypoxemic respiratory failure: A randomized controlled trial

BACKGROUND AND OBJECTIVE

The relative effectiveness of initial non-invasive respiratory strategies for acute respiratory failure using continuous positive airway pressure (CPAP) or high-flow nasal cannula (HFNC) is unclear.

METHODS

We conducted a multicenter, open-label, parallel-group randomized controlled trial to compare the efficacy of CPAP and HFNC on reducing the risk of meeting the prespecified criteria for intubation and improving clinical outcomes of acute hypoxemic respiratory failure. The primary endpoint was the time taken to meet the prespecified criteria for intubation within 28 days.

RESULTS

Eighty-five patients were randomly assigned to the CPAP or HFNC group. Eleven (28.9%) in the CPAP group and twenty (42.6%) in the HFNC group met the criteria for intubation within 28 days. Compared with HFNC, CPAP reduced the risk of meeting the intubation criteria (hazard ratio [HR], 0.327; 95% CI, 0.148-0.724; p = 0.006). There were no significant between-group differences in the intubation rates, in-hospital and 28-day mortality rates, ventilator-free days, duration of the need for respiratory support, or duration of hospitalization for respiratory illness. Pulmonary oxygenation was significantly better in the CPAP group, with significantly lower pH and higher partial pressure of carbon dioxide, but there were no differences in the respiratory rate between groups. CPAP and HFNC were associated with few possibly causal adverse events.

CONCLUSION

CPAP is more effective than HFNC at reducing the risk of meeting the intubation criteria in patients with acute hypoxemic respiratory failure.

Outcomes of Invasive and Noninvasive Ventilation in a Haitian Emergency Department

Background

Limited data exist on the outcomes of patients requiring invasive ventilation or noninvasive positive pressure ventilation (NIPPV) in low-income countries. To our knowledge, no study has investigated this topic in Haiti.

Objectives

We describe the clinical epidemiology, treatment, and outcomes of patients requiring NIPPV or intubation in an emergency department (ED) in rural Haiti.

Methods

This is an observational study utilizing a convenience sample of adult and pediatric patients requiring NIPPV or intubation in the ED at an academic hospital in central Haiti from January 2019-February 2021. Patients were prospectively identified at the time of clinical care. Data on demographics, clinical presentation, management, and ED disposition were extracted from patient charts using a standardized form and analyzed in SAS v9.4. The primary outcome was survival to discharge.

Findings

Of 46 patients, 27 (58.7%) were female, mean age was 31 years, and 14 (30.4%) were pediatric (age <18 years). Common diagnoses were cardiogenic pulmonary edema, pneumonia/pulmonary sepsis, and severe asthma. Twenty-three (50.0%) patients were initially treated with NIPPV, with 4 requiring intubation; a total of 27 (58.7%) patients were intubated. Among those for whom intubation success was documented, first-pass success was 57.7% and overall success was 100% (one record missing data); intubation was associated with few immediate complications. Twenty-two (47.8%) patients died in the ED. Of the 24 patients who survived, 4 were discharged, 19 (intubation: 12; NIPPV: 9) were admitted to the intensive care unit or general ward, and 1 was transferred. Survival to discharge was 34.8% (intubation: 22.2%; NIPPV: 52.2%); 1 patient left against medical advice following admission.

Conclusions

Patients with acute respiratory failure in this Haitian ED were successfully treated with both NIPPV and intubation. While overall survival to discharge remains relatively low, this study supports developing capacity for advanced respiratory interventions in low-resource settings.

Effects of CPAP and FiO2 on respiratory effort and lung stress in early COVID-19 pneumonia: a randomized, crossover study

BACKGROUND

in COVID-19 acute respiratory failure, the effects of CPAP and FiO2 on respiratory effort and lung stress are unclear. We hypothesize that, in the compliant lungs of early Sars-CoV-2 pneumonia, the application of positive pressure through Helmet-CPAP may not decrease respiratory effort, and rather worsen lung stress and oxygenation when compared to higher FiO2 delivered via oxygen masks.

METHODS

In this single-center (S.Luigi Gonzaga University-Hospital, Turin, Italy), randomized, crossover study, we included patients receiving Helmet-CPAP for early (< 48 h) COVID-19 pneumonia without additional cardiac or respiratory disease. Healthy subjects were included as controls. Participants were equipped with an esophageal catheter, a non-invasive cardiac output monitor, and an arterial catheter. The protocol consisted of a random sequence of non-rebreather mask (NRB), Helmet-CPAP (with variable positive pressure and FiO2) and Venturi mask (FiO2 0.5), each delivered for 20 min. Study outcomes were changes in respiratory effort (esophageal swing), total lung stress (dynamic + static transpulmonary pressure), gas-exchange and hemodynamics.

RESULTS

We enrolled 28 COVID-19 patients and 7 healthy controls. In all patients, respiratory effort increased from NRB to Helmet-CPAP (5.0 ± 3.7 vs 8.3 ± 3.9 cmH2O, p < 0.01). However, Helmet's pressure decreased by a comparable amount during inspiration (- 3.1 ± 1.0 cmH2O, p = 0.16), therefore dynamic stress remained stable (p = 0.97). Changes in static and total lung stress from NRB to Helmet-CPAP were overall not significant (p = 0.07 and p = 0.09, respectively), but showed high interpatient variability, ranging from - 4.5 to + 6.1 cmH2O, and from - 5.8 to + 5.7 cmH2O, respectively. All findings were confirmed in healthy subjects, except for an increase in dynamic stress (p < 0.01). PaO2 decreased from NRB to Helmet-CPAP with FiO2 0.5 (107 ± 55 vs 86 ± 30 mmHg, p < 0.01), irrespective of positive pressure levels (p = 0.64). Conversely, with Helmet's FiO2 0.9, PaO2 increased (p < 0.01), but oxygen delivery remained stable (p = 0.48) as cardiac output decreased (p = 0.02). When PaO2 fell below 60 mmHg with VM, respiratory effort increased proportionally (p < 0.01, r = 0.81).

CONCLUSIONS

In early COVID-19 pneumonia, Helmet-CPAP increases respiratory effort without altering dynamic stress, while the effects upon static and total stress are variable, requiring individual assessment. Oxygen masks with higher FiO2 provide better oxygenation with lower respiratory effort. Trial registration Retrospectively registered (13-May-2021): clinicaltrials.gov (NCT04885517), https://clinicaltrials.gov/ct2/show/NCT04885517 .

COVID-19 Acute Respiratory Distress Syndrome: Treatment with Helmet CPAP in Respiratory Intermediate Care Unit by Pulmonologists in the Three Italian Pandemic Waves

COVID-19 Acute Respiratory Distress Syndrome (CARDS) is the most serious complication of COVID-19. The SARS-CoV-2 outbreaks rapidly saturated intensive care unit (ICU), forcing the application of non-invasive respiratory support (NIRS) in respiratory intermediate care unit (RICU). The primary aim of this study is to compare the patients' clinical characteristics and outcomes (Helmet-Continuous Positive Airway Pressure (H-CPAP) success/failure and survival/death). The secondary aim is to evaluate and detect the main predictors of H-CPAP success and survival/death. A total of 515 patients were enrolled in our observational prospective study based on CARDS developed in RICU during the three Italian pandemic waves. All selected patients were treated with H-CPAP. The worst ratio of arterial partial pressure of oxygen (PaO2) and fraction of inspired oxygen (FiO2) PaO2/FiO2 during H-CPAP stratified the subjects into mild, moderate and severe CARDS. H-CPAP success has increased during the three waves (62%, 69% and 77%, respectively) and the mortality rate has decreased (28%, 21% and 13%). H-CPAP success/failure and survival/death were related to the PaO2/FiO2 (worst score) ratio in H-CPAP and to steroids' administration. D-dimer at admission, FiO2 and positive end expiratory pressure (PEEP) were also associated with H-CPAP success. Our study suggests good outcomes with H-CPAP in CARDS in RICU. A widespread use of steroids could play a role.

Noninvasive ventilation in patients with acute hypoxemic respiratory failure: a systematic review and meta-analysis of randomized controlled trials

The clinical benefits of noninvasive ventilation (NIV) for patients with acute hypoxemic respiratory failure (AHRF) is still inconclusive. We aimed to evaluate the effect of NIV compared with conventional oxygen therapy (COT)/high-flow nasal cannula (HFNC) in this patient population. We searched for relevant studies from PubMed, Embase, Cochrane Library, ClinicalTrials.gov, CINHAL, Web of Science up to August 2019 for randomized controlled trials (RCTs) that compared NIV with COT/HFNC in AHRF. The primary outcome was the tracheal intubation rate. Secondary outcomes were intensive care unit (ICU) mortality, and hospital mortality. We applied the GRADE approach to grade the strength of the evidence. Seventeen RCTs that recruited 1738 patients were included in our meta-analysis. When comparing NIV versus COT/HFNC, the pooled risk ratio (RR) for the tracheal intubation rate was 0.68, 95% confidence interval (CI) 0.52-0.89, p = 0.005, I² = 72.4%, low certainty of evidence. There were no significant differences in ICU mortality (pooled RR = 0.87, 95% CI 0.60-1.26), p = 0.45, I² = 64.6%) and hospital mortality (pooled RR = 0.71, 95% CI 0.51-1.00, p = 0.05, I² = 27.4%). Subgroup analysis revealed that NIV application with helmet was significantly associated with a lower intubation rate than NIV with face mask. NIV did not show a significant reduction in intubation rate compared to HFNC. In conclusion, NIV application in patients with medical illness and AHRF was associated with a lower risk of tracheal intubation compared to COT. NIV with helmet and HFNC are promising strategies to avoid tracheal intubation in this patient population and warrant further studies. NIV application had no effect on mortality.The study protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD42018087342).

Update on the management of acute respiratory failure using non-invasive ventilation and pulse oximetry

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2023. Other selected articles can be found online at  https://www.biomedcentral.com/collections/annualupdate2023 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from  https://link.springer.com/bookseries/8901 .

Does High Flow Nasal Cannula avoid intubation and improve the mortality of adult patients in acute respiratory failure in the intensive care setting, when compared to others methods as Conventional Oxygen Therapy or Non-Invasive Ventilation? A narrative review

High-flow oxygen therapy via nasal cannula (HFNC) has been used for many years to oxygenate patients in respiratory failure. However, scientific data in literature are divergent about its value to prevent invasive mechanical ventilation and mortality. The use of HFNC has increased following the COVID-19 pandemic. Our review considers the impact of HFNC on intubation rates and mortality compared with conventional oxygen therapy (COT) and noninvasive ventilation (NIV). HFNC would decrease the use of invasive mechanical ventilation compared to COT and would be equivalent to NIV. Combination of NIV and HFNC would have a benefit compared to NIV alone. Some etiologies of respiratory failure would benefit more from this technique as post-extubation critical ill patient or COVID-19 pneumonia. HFNC seems to reduce mortality in COVID-19 patients compared to NIV.

Breathing pattern, accessory respiratory muscles work, and gas exchange evaluation for prediction of NIV failure in moderate-to-severe COVID-19-associated ARDS after deterioration of respiratory failure outside ICU: the COVID-NIV observational study

BACKGROUND

Data on the efficacy of non-invasive ventilation (NIV) after progression of respiratory failure in patients who have already received oxygen therapy, or CPAP outside ICU is limited. The study aimed to find predictors of NIV failure based on breathing pattern, gas exchange, and accessory respiratory muscles evaluation in patients who progressed to moderate-to-severe COVID-19 ARDS.

METHODS

This was a prospective observational study in patients with moderate-to-severe COVID-19-ARDS on NIV (n = 80) admitted to COVID-ICU of Sechenov University. The combined success rate for conventional oxygen and CPAP outside ICU was 78.6% (440 of 560 patients). The primary endpoints were intubation rate and mortality. We measured respiratory rate, exhaled tidal volume (Vte), mean peak inspiratory flow (PIF), inspiratory time (Ti), PaO₂, SpO₂, end-tidal carbon dioxide (P_ETCO₂), and Patrick score, and calculated ROX index, PaO₂/FiO₂, ventilatory ratio, and alveolar dead space (Vdalv/Vt) on Days 1, 3, 5, 7, 10, and 14. For all significant differences between NIV success and failure groups in measured data, we performed ROC analysis.

RESULTS

NIV failure rate in ICU after deterioration of respiratory failure outside ICU was 71.3% (n = 57). Patients with the subsequent NIV failure were older at inclusion, more frail, had longer duration of disease before ICU admission, and higher rate of CPAP use outside ICU. ROC-analysis revealed that the following respiratory parameters after 48 h of NIV can serve as a predictors for NIV failure in moderate-to-severe COVID-19-associated ARDS: PaO₂/FiO₂ < 112 mmHg (AUROC 0.90 (0.93-0.97), p < 0.0001); P_ETCO₂ < 19.5 mmHg (AUROC 0.84 (0.73-0.94), p < 0.0001); VDalv/VT > 0.43 (AUROC 0.78 (0.68-0.90), p < 0.0001); ROX-index < 5.02 (AUROC 0.89 (0.81-0.97), p < 0.0001); Patrick score > 2 points (AUROC 0.87 (0.78-0.96), p = 0.006).

CONCLUSION

In patients who progressed to moderate-to-severe COVID-19-ARDS probability of NIV success rate was about 1/3. Prediction of the NIV failure can be made after 48 h based on ROX index < 5.02, PaO₂/FiO₂ < 112 mmHg, P_ETCO2 < 19.5 mmHg, and Patrick score >  = 2.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04667923 , registered on 16/12/2020.