Effect of post-extubation high-flow nasal cannula combined with respiratory training versus conventional oxygen therapy on postoperative pulmonary complications in patients after major abdominal surgery: protocol for a single-centre randomized controlled trial

BACKGROUND

Nearly 234 million patients undergo surgery each year, and 1.3 million among them develop complications. Patients undergoing major upper abdominal surgery (operation time > 2 h) have a really high incidence of postoperative pulmonary complications (PPCs). The occurrence of PPCs seriously affects the outcomes of patients. High-flow nasal cannula (HFNC) is as effective as noninvasive ventilation (NIV) in preventing postoperative hypoxaemia and respiratory failure. Respiratory training using positive expiratory pressure (PEP) Acapella (Choice) has been shown to help patients with rapid recovery from postoperative atelectasis. However, no relevant randomized controlled studies have been conducted to clarify the effect of HFNC combined with respiratory training in the prevention of PPCs. This study aims to investigate whether the use of HFNC combined with respiratory training could reduce the incidence of PPCs within 7 days after major upper abdominal surgery compared to that with conventional oxygen therapy (COT).

METHODS

This is a randomized controlled single-centre trial. A total of 328 patients who undergo major abdominal surgery will be included. Subjects who fulfil the eligible criteria will be randomly assigned into the combination treatment group (Group A) or COT group (Group B) after extubation. The interventions will begin within 30 min of extubation. Patients in Group A will receive HFNC for at least 48 h and respiratory training three times a day for at least 72 h. Patients in Group B will receive oxygen therapy through a nasal catheter or mask for at least 48 h. Our primary endpoint is the incidence of PPCs within 7 days, and the secondary outcome measures include 28-day mortality, reintubation rate, length of hospital stay, and all-cause mortality within 1 year.

DISCUSSION

This trial would help provide evidence on the effectivity of applying HFNC combined with respiratory training for the prevention of PPCs in patients undergoing major upper abdominal surgery. The objective of this study is to determine the optimal treatment approach to improve the prognosis of patients undergoing surgery.

TRIAL REGISTRATION

ChiCTR2100047146. Registered on 8 June 2021. Retrospectively registered.

Effect of different ventilation modalities on the early prognosis of patients with sleep apnea after acute ischemic stroke---protocol for a prospective, open-label and randomised controlled trial

BACKGROUND

Sleep apnea is highly prevalent after acute ischemic stroke (AIS) and has increased stroke-related mortality and morbidity. The conventional sleep apnea treatment is continuous positive airway pressure (CPAP) ventilation. However, it is poorly tolerated by patients and is not used in all stroke patients. This protocol describes the impact of high-flow nasal cannula (HFNC) oxygen therapy compared to nasal continuous positive airway pressure (nCPAP) ventilation or usual care on the early prognosis of patients with sleep apnea after AIS.

METHODS

This randomised controlled study will be conducted in the intensive care unit of the Department of Neurology at the Wuhan Union Hospital. According to the study plan, 150 patients with sleep apnea after AIS will be recruited. All patients are randomly allocated in a 1:1:1 ratio to one of three groups: the nasal catheter group (standard oxygen group), the HFNC group, and the nCPAP group. Patients receive different types of ventilation after admission to the group, and their tolerance while using the different ventilation is recorded. Patients will be followed up by telephone three months after discharge, and stroke recovery is recorded. The primary outcomes were 28-day mortality, the incidence of pulmonary infection and endotracheal intubation.

DISCUSSION

This study analyses different ventilation modalities for early interventions in patients with sleep apnea after AIS. We will investigate whether nCPAP and HFNC reduce early mortality and endotracheal intubation rates and improve distant neurological recovery in patients.

TRIAL REGISTRATION

This trial was registered at ClinicalTrials.gov (NCT05323266; 25 March 2022).

Optimal machine learning methods for prediction of high-flow nasal cannula outcomes using image features from electrical impedance tomography

BACKGROUND

High-flow nasal cannula (HNFC) is able to provide ventilation support for patients with hypoxic respiratory failure. Early prediction of HFNC outcome is warranted, since failure of HFNC might delay intubation and increase mortality rate. Existing methods require a relatively long period to identify the failure (approximately 12 h) and electrical impedance tomography (EIT) may help identify the patient's respiratory drive during HFNC.

OBJECTIVES

This study aimed to investigate a proper machine-learning model to predict HFNC outcomes promptly by EIT image features.

METHODS

The Z-score standardization method was adopted to normalize the samples from 43 patients who underwent HFNC and six EIT features were selected as model input variables through the random forest feature selection method. Machine-learning methods including discriminant, ensembles, k-nearest neighbour (KNN), artificial neural network (ANN), support vector machine (SVM), AdaBoost, xgboost, logistic, random forest, bernoulli bayes, gaussian bayes and gradient-boosted decision trees (GBDT) were used to build prediction models with the original data and balanced data proceeded by the synthetic minority oversampling technique.

RESULTS

Prior to data balancing, an extremely low specificity (less than 33.33%) as well as a high accuracy in the validation data set were observed in all the methods. After data balancing, the specificity of KNN, xgboost, random forest, GBDT, bernoulli bayes and AdaBoost significantly reduced (p<0.05) while the area under curve did not improve considerably (p>0.05); and the accuracy and recall decreased significantly (p<0.05).

CONCLUSIONS

The xgboost method showed better overall performance for balanced EIT image features, which may be considered as the ideal machine learning method for early prediction of HFNC outcomes.

Comparison of the efficacy and comfort of high-flow nasal cannula with different initial flow settings in patients with acute hypoxemic respiratory failure: a systematic review and network meta-analysis

BACKGROUND

High-flow nasal cannula (HFNC) has been proven effective in improving patients with acute hypoxemic respiratory failure (AHRF), but a discussion of its use for initial flow settings still need to be provided. We aimed to compare the effectiveness and comfort evaluation of HFNC with different initial flow settings in patients with AHRF.

METHODS

Studies published by October 10, 2022, were searched exhaustively in PubMed, Embase, Web of Science, Cochrane Library (CENTRAL), and the China National Knowledge Infrastructure (CNKI) database. Network meta-analysis (NMA) was performed with STATA 17.0 and R software (version 4.2.1). A Bayesian framework was applied for this NMA. Comparisons of competing models based on the deviance information criterion (DIC) were used to select the best model for NMA. The primary outcome is the intubation at day 28. Secondary outcomes included short-term and long-term mortality, comfort score, length of ICU or hospital stay, and 24-h PaO₂/FiO₂.

RESULTS

This NMA included 23 randomized controlled trials (RCTs) with 5774 patients. With NIV as the control, the HFNC_high group was significantly associated with lower intubation rates (odds ratio [OR] 0.72 95% credible interval [CrI] 0.56 to 0.93; moderate quality evidence) and short-term mortality (OR 0.81 95% CrI 0.69 to 0.96; moderate quality evidence). Using HFNC_Moderate (Mod) group (mean difference [MD] - 1.98 95% CrI -3.98 to 0.01; very low quality evidence) as a comparator, the HFNC_Low group had a slight advantage in comfort scores but no statistically significant difference. Of all possible interventions, the HFNC_High group had the highest probability of being the best in reducing intubation rates (73.04%), short-term (82.74%) and long-term mortality (67.08%). While surface under the cumulative ranking curve value (SUCRA) indicated that the HFNC_Low group had the highest probability of being the best in terms of comfort scores.

CONCLUSIONS

The high initial flow settings (50-60 L/min) performed better in decreasing the occurrence of intubation and mortality, albeit with poor comfort scores. Treatment of HFNC for AHRF patients ought to be initiated from moderate flow rates (30-40 L/min), and individualized flow settings can make HFNC more sensible in clinical practice.

The effectiveness of supplemental oxygen and high-flow nasal cannula therapy in patients with obstructive sleep apnea in different clinical settings: A systematic review and meta-analysis

STUDY OBJECTIVE

To evaluate the effectiveness of supplemental oxygen therapy and high-flow nasal cannula (HFNC) therapy in patients with obstructive sleep apnea (OSA) in different clinical settings to assess its application to surgical patients in the postoperative setting.

DESIGN

A systematic search was conducted on MEDLINE and other databases from 1946 to December 16th, 2021. Title and abstract screening were conducted independently, and the lead investigators resolved conflicts. Meta-analyses were performed using a random-effects model and are presented as mean difference and standardized mean difference with 95% confidence intervals. These were calculated using RevMan 5.4.

PATIENTS

1395 and 228 OSA patients underwent oxygen therapy and HFNC therapy respectively.

INTERVENTIONS

Oxygen therapy and HFNC therapy.

MEASUREMENTS

Apnea-hypopnea index (AHI), oxyhemoglobin saturation (SpO₂), cumulative time with SPO₂ < 90% (CT90).

MAIN RESULTS

Twenty-seven oxygen therapy studies were included in the review, with ten randomized controlled trials (RCT), seven randomized crossovers, seven non-randomized crossovers, and three prospective cohorts. Pooled analyses showed that oxygen therapy significantly reduced AHI by 31% and increased SpO₂ by 5% versus baseline, and CPAP significantly reduced AHI by 84%, and increased SpO₂ by 3% versus baseline. CPAP was 53% more effective in reducing AHI than oxygen therapy, but both treatments had similar effectiveness in increasing SpO₂. Nine HFNC studies were included in the review, with five prospective cohorts, three randomized crossovers, and one RCT. Pooled analyses showed that HFNC therapy significantly reduced AHI by 36% but did not substantially increase SpO₂.

CONCLUSIONS

Oxygen therapy effectively reduces AHI and increases SpO₂ in patients with OSA. CPAP is more effective in reducing AHI than oxygen therapy. HFNC therapy is effective in reducing AHI. Although both oxygen therapy and HFNC therapy effectively reduce AHI, more research is needed to draw conclusions on clinical outcomes.

Comparison of preoxygenation efficiency measured by the oxygen reserve index between high-flow nasal oxygenation and facemask ventilation: a randomised controlled trial

BACKGROUND

High-flow nasal oxygenation and the oxygen reserve index (ORI), which is a non-invasive and innovative modality that reflects the arterial oxygen content, are used in general anaesthesia. This study compares the preoxygenation efficiency (measured by the ORI) of high-flow nasal oxygenation and facemask ventilation during the induction process.

METHODS

This single-centre, two-group, randomised controlled trial included 197 patients aged ≥ 20 years who underwent orotracheal intubation for general anaesthesia for elective surgery. The patients were randomly allocated to receive preoxygenation via facemask ventilation or high-flow nasal oxygenation. The ORI was measured and compared between both groups.

RESULTS

The ORI increased during preoxygenation in all patients. At 1 min of preoxygenation, the ORI was significantly higher in the high-flow nasal oxygenation group (0.34 ± 0.33) than in the facemask ventilation group (0.21 ± 0.28; P = 0.003). The highest ORI was not significantly different between the two groups (0.68 ± 0.25 in the high-flow nasal oxygenation group vs. 0.70 ± 0.28 in the facemask ventilation group; P = 0.505).

CONCLUSIONS

High-flow nasal oxygenation results in an oxygenation status similar to that provided by facemask ventilation during the induction process of general anaesthesia; therefore, high-flow nasal oxygenation is a feasible preoxygenation method.

TRIAL REGISTRATION

Clinicaltrials.gov (NCT04291339).

Cardiopulmonary outcomes following high flow nasal cannula in pediatric population: A systematic review

BACKGROUND

The high-flow nasal cannula (HFNC) has received much attention in various clinical settings and has been approved recently for application in pediatric care.

OBJECTIVES

To determine whether HFNC use improves cardiopulmonary outcomes in pediatric patients with the cardiac disease more effectively than alternative oxygen therapies.

METHODS

Systematic review was performed using PubMed, Scopus, and Web of Science databases. Randomized controlled trials comparing HFNC with alternative oxygen therapies and observational studies that solely reported on the use of HFNC in the pediatric population were included between 2012 and 2022.

RESULTS

Nine studies with approximately 656 patients were reported in this review. HFNC significantly increased systemic oxygen saturation across all literature investigating this parameter. Other notable outcomes in HFNC patients included normalizing heart rate, partial blood pressure, and PaO₂/FiO₂ ratio. However, some studies reported a complication rate concurrent with traditional oxygen therapies, and a suggested HFNC failure rate of 50% was observed.

CONCLUSIONS

Compared with traditional oxygen therapies, HFNC can reduce anatomical dead space and normalize systemic oxygen saturation, PaO2/FiO2 ratio, heart rate, and partial blood pressure. We advocate using HFNC therapy in children with cardiac diseases as the currently available evidence supports HFNC use over other oxygenation treatments in the pediatric population.

Association of Monocyte Distribution Width with the Need for Respiratory Support in Hospitalized COVID-19 Patients

Background

The monocyte distribution width (MDW), a novel inflammatory biomarker reflecting morphological changes in response to inflammation, has been shown to be useful in identifying COVID-19 infection or predicting death. However, data on the association with predicting the need for respiratory support are still limited. The aim of this study was to determine the association of MDW with the need for respiratory support in patients with SARS-CoV-2 infection.

Patients and methods

This is a single-center retrospective cohort study. Consecutive hospitalized COVID-19 adult patients who presented at the outpatient department (OPD) or emergency department (ED) between May and August 2021 were enrolled. Respiratory support was defined as any one of the following: conventional oxygen therapy, high-flow oxygen nasal cannula, noninvasive, or invasive mechanical ventilation. The performance of MDW was measured using the area under the receiver operating characteristic (AuROC) curve.

Results

Of the 250 enrolled patients, 122 (48.8%) patients received respiratory support. The mean MDW was significantly higher in the respiratory support group: 27.2 ± 4.6 vs 23.6 ± 4.1 (p < 0.001). The MDW ≥ 25 had the best AuROC characteristics of 0.70 (95% CI: 0.65-0.76).

Conclusions

The MDW is a potential biomarker that may aid in identifying individuals at risk of requiring oxygen support in COVID-19 and can be easily implemented in clinical practice.

How to cite this article

Daorattanachai K, Hirunrut C, Pirompanich P, Weschawalit S, Srivilaithon W. Association of Monocyte Distribution Width with the Need for Respiratory Support in Hospitalized COVID-19 Patients. Indian J Crit Care Med 2023;27(5):352-357.

Effect of high-flow nasal cannula on patients' recovery after inhalation general anesthesia

Objective

To investigate the effect of high-flow nasal cannula (HFNC) and Oxygen Nebuliser mask (ONM) on patients recovering from inhalation anesthesia.

Methods

A retrospective analysis was performed on 128 patients after inhalation of general anesthesia in the recovery room of the Anesthesiology Department of The Fourth Hospital of Hebei Medical University from September 2019 to September 2021. All patients received the same anesthesia induction and analgesia methods, inhalation anesthesia or intravenous-inhalation anesthesia maintenance, recovered spontaneous breathing and removed endotracheal intubation after surgery, then were divided into HFNC group and ONM group for oxygen therapy. HFNC setting mode: flow rate: 20-60 L/minutes, humidification temperature: 37°C, the oxygen concentration was adjusted to maintain finger pulse oxygen saturation SPO2>90%; ONM group, the oxygen flow rate was adjusted to maintain finger pulse oxygen saturation SPO2>90%. All patients in the two groups were compared immediately after they entered the recovery room for 0 minutes,, 10 minutes, and 20 minutes,, including tidal volume, blood gas, Richmond Agitation-Sedation Scale (RASS) score and time from sedation to awakening.

Results

The changes in tidal volume, oxygenation index and RASS score over time in the HFNC group were higher than those in the ONM group (p<0.05), and the awakening time in the HFNC group was faster than that in the ONM group (p<0.01), with significant statistical differences.

Conclusions

Compared with ONM, HFNC can shorten postoperative recovery time, reduce the incidence of agitation and improve lung function and oxygenation state during recovery from anesthesia.

[COVID-19-associated lung weakness (CALW): Systematic review and meta-analysis]

Objectives

To assess mortality and different clinical factors derived from the development of atraumatic pneumothorax (PNX) and/or pneumomediastinum (PNMD) in critically ill patients as a consequence of COVID-19-associated lung weakness (CALW).

Design

Systematic review with meta-analysis.

Setting

Intensive care unit (ICU).

Participants

Original research evaluating patients, with or without the need for protective invasive mechanical ventilation (IMV), with a diagnosis of COVID-19 who had developed atraumatic PNX or PNMD on admission or during their hospital stay.

Interventions

Data of interest were obtained from each article and analysed and assessed by the Newcastle-Ottawa Scale. The risk of the variables of interest was assessed by data derived from studies including patients who developed atraumatic PNX or PNMD.

Main variables of interest

Mortality, mean ICU length of stay and mean PaO₂/FiO₂ at diagnosis.

Results

Data were collected from 12 longitudinal studies. Data from a total of 4,901 patients were included in the meta-analysis. A total of 1,629 patients had an episode of atraumatic PNX and 253 patients had an episode of atraumatic PNMD. Despite finding significantly strong associations, the high heterogeneity between studies means that interpretation of the results should be made with caution.

Conclusions

Mortality of COVID-19 patients was higher in those who developed atraumatic PNX and/or PNMD compared to those who did not. The mean PaO2/FiO2 index was lower in patients who developed atraumatic PNX and/or PNMD. We propose to group these cases under the term CAPD.

Heated humidified high flow nasal cannula therapy in children with obstructive sleep apnea: A randomized cross-over trial

OBJECTIVE/BACKGROUND

Moderate-to-severe obstructive sleep apnea (OSA) is highly prevalent in children with obesity and/or underlying medical complexity. The first line of therapy, adenotonsillectomy (AT), does not cure OSA in more than 50% of these children. Consequently, continuous positive airway pressure (CPAP) is the main therapeutic option but adherence is often poor. A potential alternative which may be associated with greater adherence is heated high-flow nasal cannula (HFNC) therapy; however, its efficacy in children with OSA has not been systematically investigated. The study aimed to compare the efficacy of HFNC with CPAP to treat moderate-to-severe OSA with the primary outcome measuring the change from baseline in the mean obstructive apnea/hypopnea index (OAHI).

PARTICIPANTS/METHODS

This was a single-blinded randomized, two period crossover trial conducted from March 2019 to December 2021 at a Canadian pediatric quaternary care hospital. Children aged 2-18 years with obesity and medical complexity diagnosed with moderate-to-severe OSA via overnight polysomnography and recommended CPAP therapy were included in the study. Following diagnostic polysomnography, each participant completed two further sleep studies; a HFNC titration study and a CPAP titration study (9 received HFNC first, and 9 received CPAP first) in a random 1:1 allocation order.

RESULTS

Eighteen participants with a mean ± SD age of 11.9 ± 3.8 years and OAHI 23.1 ± 21.7 events/hour completed the study. The mean [95% CI] reductions in OAHI (-19.8[-29.2, -10.5] vs. -18.8 [-28.2, -9.4] events/hour, p = 0.9), nadir oxygen saturation (7.1[2.2, 11.9] vs. 8.4[3.5, 13.2], p = 0.8), oxygen desaturation index (-11.6[-21.0, -2.3] vs. -16.0[-25.3, -6.6], p = 0.5) and sleep efficiency (3.5[-4.8, 11.8] vs. 9.2[0.9, 15.5], p = 0.2) with HFNC and CPAP therapy were comparable between conditions.

CONCLUSION

HFNC and CPAP therapy yield similar reductions in polysomnography quantified measures of OSA severity among children with obesity and medical complexities.

TRIAL REGISTRATION

NCT05354401 ClinicalTrials.gov.

The efficacy of high-flow nasal cannula (HFNC) versus non-invasive ventilation (NIV) in patients at high risk of extubation failure: a systematic review and meta-analysis

BACKGROUND

Studies suggest that high-flow nasal cannula (HFNC) and non-invasive ventilation (NIV) can prevent reintubation in critically ill patients with a low risk of extubation failure. However, the safety and effectiveness in patients at high risk of extubation failure are still debated. Therefore, we conducted a systematic review and meta-analysis to compare the efficacies of HFNC and NIV in high-risk patients.

METHODS

We searched eight databases (MEDLINE, Cochrane Library, EMBASE, CINAHL Complete, Web of Science, China National Knowledge Infrastructure, Wan-Fang Database, and Chinese Biological Medical Database) with reintubation as a primary outcome measure. The secondary outcomes included mortality, intensive care unit (ICU) length of stay (LOS), incidence of adverse events, and respiratory function indices. Statistical data analysis was performed using RevMan software.

RESULTS

Thirteen randomized clinical trials (RCTs) with 1457 patients were included. The HFNC and NIV groups showed no differences in reintubation (RR 1.10, 95% CI 0.87-1.40, I² = 0%, P = 0.42), mortality (RR 1.09, 95% CI 0.82-1.46, I² = 0%, P = 0.54), and respiratory function indices (partial pressure of carbon dioxide [PaCO₂]: MD - 1.31, 95% CI - 2.76-0.13, I² = 81%, P = 0.07; oxygenation index [P/F]: MD - 2.18, 95% CI - 8.49-4.13, I² = 57%, P = 0.50; respiratory rate [Rr]: MD - 0.50, 95% CI - 1.88-0.88, I² = 80%, P = 0.47). However, HFNC reduced adverse events (abdominal distension: RR 0.09, 95% CI 0.04-0.24, I² = 0%, P < 0.01; aspiration: RR 0.30, 95% CI 0.09-1.07, I² = 0%, P = 0.06; facial injury: RR 0.27, 95% CI 0.09-0.88, I² = 0%, P = 0.03; delirium: RR 0.30, 95%CI 0.07-1.39, I² = 0%, P = 0.12; pulmonary complications: RR 0.67, 95% CI 0.46-0.99, I² = 0%, P = 0.05; intolerance: RR 0.22, 95% CI 0.08-0.57, I² = 0%, P < 0.01) and may have shortened LOS (MD - 1.03, 95% CI - 1.86-- 0.20, I² = 93%, P = 0.02). Subgroup analysis by language, extubation method, NIV parameter settings, and HFNC flow rate revealed higher heterogeneity in LOS, PaCO₂, and Rr.

CONCLUSIONS

In adult patients at a high risk of extubation failure, HFNC reduced the incidence of adverse events but did not affect reintubation and mortality. Consequently, whether or not HFNC can reduce LOS and improve respiratory function remains inconclusive.

High-flow cannula for frail patients with SARS-CoV-2 infection non-eligible for intensive care unit management

OBJECTIVES

High-flow nasal cannula (HFNC) was widely used during the COVID-19 pandemic in intensive care units (ICU), but there is no recommendation for elderly patients non-eligible for ICU management. We aimed to describe the outcomes of HFNC treatment in patients with COVID-19 who are not eligible for ICU management.

METHODS

Retrospective bicentric cohort study performed between September 1, 2020 and June 30, 2021 in two infectious diseases departments of Colmar Hospital and Antoine Beclere University Hospital, France.

RESULTS

Sixty-four patients were treated with HFNC: 33 in Colmar and 31 in Beclere hospital (median age: 85 years; IQ, 82-92). Of these, 16 patients survived (25%). Surviving patients had a lower Charlson comorbidity index score than deceased patients (five vs six; p = 0.02).

CONCLUSIONS

Despite a high death rate, with survivors being younger and having fewer comorbidities, HFNC is an easy tool to implement in non-ICU wards for the frailest patients.

The effects of flow settings during high-flow nasal cannula support for adult subjects: a systematic review

BACKGROUND

During high-flow nasal cannula (HFNC) therapy, flow plays a crucial role in the physiological effects. However, there is no consensus on the initial flow settings and subsequent titration. Thus, we aimed to systematically synthesize the effects of flows during HFNC treatment.

METHODS

In this systematic review, two investigators independently searched PubMed, Embase, Web of Science, Scopus, and Cochrane for in vitro and in vivo studies investigating the effects of flows in HFNC treatment published in English before July 10, 2022. We excluded studies that investigated the pediatric population (< 18 years) or used only one flow. Two investigators independently extracted the data and assessed the risk of bias. The study protocol was prospectively registered with PROSPERO, CRD42022345419.

RESULTS

In total, 32,543 studies were identified, and 44 were included. In vitro studies evaluated the effects of flow settings on the fraction of inspired oxygen (F_IO₂), positive end-expiratory pressure, and carbon dioxide (CO₂) washout. These effects are flow-dependent and are maximized when the flow exceeds the patient peak inspiratory flow, which varies between patients and disease conditions. In vivo studies report that higher flows result in improved oxygenation and dead space washout and can reduce work of breathing. Higher flows also lead to alveolar overdistention in non-dependent lung regions and patient discomfort. The impact of flows on different patients is largely heterogeneous.

INTERPRETATION

Individualizing flow settings during HFNC treatment is necessary, and titrating flow based on clinical findings like oxygenation, respiratory rates, ROX index, and patient comfort is a pragmatic way forward.

Effect of high-flow nasal cannula therapy on thirst sensation and dry mouth after extubation: A single-centre prospective cohort study

OBJECTIVES

Little is known regarding the association between the type of oxygen therapy and thirst sensation after extubation. This study aimed to assess the effect of post-extubation high-flow nasal cannula on thirst.

RESEARCH METHODOLOGY/DESIGN AND SETTING

This single-centre prospective cohort study included 100 ventilated patients. After extubation, patients received either high-flow nasal cannula (n = 19) or conventional oxygen therapy (n = 81). Thirst intensity was evaluated by a self-reporting numeric rating scale, and dry mouth was defined objectively using an oral moisture checking device.

MAIN OUTCOME MEASURES

The primary outcome was thirst intensity 24 hours post-extubation. Secondary outcomes were thirst intensity at 4 hours post-extubation and prevalence of dry mouth at 4 hours and 24 hours post-extubation.

RESULTS

At 24 hours post-extubation, the median (interquartile range) thirst intensity was 5 (1, 7) in the high-flow nasal cannula group and 5 (4, 6) in the conventional oxygen group. After adjustment, high-flow nasal cannula therapy was significantly associated with lower thirst intensity (adjusted odds ratio, 0.14; 95 % confidence interval (CI) 0.04-0.49; P = 0.002). At 4 hours post-extubation, high-flow nasal cannula was also associated with lower thirst intensity (adjusted odds ratio, 0.19; 95 % CI, 0.06-0.60; P = 0.005). The number of patients with dry mouth was not significantly different between the two groups (high-flow vs conventional oxygen therapy, 42.1 % vs 30.9 % [4 hours after extubation]; 47.4 % vs 34.6 % [24 hours after extubation]).

CONCLUSIONS

High-flow nasal cannula therapy was associated with lower thirst intensity than conventional oxygen therapy following extubation. However, there was no significant difference in the prevalence of dry mouth.

ROX index versus HACOR scale in predicting success and failure of high-flow nasal cannula in the emergency department for patients with acute hypoxemic respiratory failure: a prospective observational study

BACKGROUND

High-flow nasal cannula has been a promising initial respiratory support measure for patients with acute hypoxemic respiratory failure (AHRF) in the emergency department (ED). However, delayed detection of HFNC failure is associated with increased mortality. The ROX index is a tool that can help predict HFNC success. Nonetheless, its utility in ED patients is limited, and no studies have compared it with the HACOR scale, another tool that may be as accurate in predicting HFNC failure. Therefore, we aimed to compare the prognostic utility of the ROX index and the HACOR scale in emergency AHRF patients.

METHODS

This prospective observational study was conducted at the ED of Siriraj Hospital, Thailand, between August 2018 and February 2020. Adult patients with AHRF requiring HFNC in the ED were included. The ROX index and the HACOR scale were measured at 1, 2, and 6 h after HFNC initiation. The primary outcome was HFNC success, defined as no intolerance or escalation towards mechanical ventilation or non-invasive ventilation within 48 h.

RESULTS

A total of 75 patients were enrolled; 52 (69.3%) had a successful treatment. The ROX index was higher in the success group, while the HACOR scale was lower at all timepoints. The ROX index yielded generally higher discrimination capacity based on the area under the receiver operating characteristic curve (AUROC) than the HACOR scale [AUROC at 1, 2, and 6 h = 0.815, 0.784, 0.853 for ROX in predicting HFNC success and 0.733, 0.690, and 0.764 for HACOR in predicting HFNC failure]. The ROX index measured at 6 h at the cut-point of 4.88 had 92.98% sensitivity, 61.11% specificity, 88.33% positive predictive value, and 73.33% negative predictive value with a diagnostic accuracy of 85.33%.

CONCLUSION

The ROX index had superior prognostic utility in predicting HFNC outcome (success/failure) compared to the HACOR scale in patients with AHRF in the ED setting. Moreover, it is less complex and more efficient to be employed at bedside. Therefore, the ROX index is a more appropriate tool to guide further management and potential escalation therapy for AHRF patients with HFNC therapy initiated in the ED.

Comparison of high-flow nasal cannula and conventional oxygen therapy for high-risk patients during bronchoscopy examination: protocol for a randomized controlled trial

INTRODUCTION

High-flow nasal cannula (HFNC) has been proven to improve oxygenation and avoid intubation in hypoxemic patients. It has also been utilized during endoscopy examination to reduce the incidence of hypoxia. However, little is known about the effects of HFNC versus conventional oxygen therapy (COT) on oxygenation during bronchoscopy examination via nasal route; particularly, no study has compared the use of HFNC with that of COT at similar F_IO₂ for patients who have high-risk factors of desaturation during bronchoscopy examination.

METHODS AND ANALYSIS

This randomized controlled trial will be implemented in four academic centers in China. Patients who have high-risk factors including hypoxemia, hypercapnia, morbid obesity, and narrow airway will be enrolled to use HFNC or COT during bronchoscopy examination. In the HFNC group, the initial gas flow will be set at 50 L/min with a fraction of inspired oxygen (F_IO₂) at 0.45, if the patient tolerates, the flow can be increased to 60L/min at most, while in the COT group, oxygen flow will be set at 6 L/min via a conventional nasal cannula. After 5 min pre-oxygenation, the bronchoscope will be inserted via the nasal route. Vital signs, oxygenation (SpO₂), and transcutaneous CO₂ (PtCO₂) will be continuously monitored. The primary outcome is the incidence of hypoxemia, defined as SpO₂ < 90% for 10 s during bronchoscopy examination, and secondary outcomes include the need for treatment escalation and adverse events.

DISCUSSION

Hypoxia is a common complication of bronchoscopy, our study attempted to demonstrate that HFNC may reduce the probability of hypoxia during bronchoscopy in high-risk patients. The results will be disseminated through peer-reviewed journals and national and international conferences.

TRIAL REGISTRATION

http://www.chictr.org.cn/ : ChiCTR2100055038. Registered on 31 December 2021.

Direct Extubation to High-Flow Nasal Cannula versus Noninvasive Ventilation in Obese Subjects

BACKGROUND

Patients who are obese have a higher risk of acute respiratory failure after extubation in the ICU. This study aimed to compare the extubation of subjects who were critically ill and obese to high-flow nasal cannula (HFNC) versus noninvasive ventilation (NIV) to determine whether HFNC can aid in reducing postextubation respiratory failure and the re-intubation rate.

METHODS

In this randomized controlled trial, subjects who were obese, defined as individuals with a body mass index ≥ 30 kg/m2, were randomly assigned to receive HFNC (n = 60) versus 60 subjects treated with NIV applied immediately after extubation. The primary outcome was the incidence of postextubation respiratory failure and re-intubation rate within 72 h. Secondary outcomes included oxygenation, breathing frequency, subjective dyspnea, ICU and hospital length of stay, and ICU mortality at day 28.

RESULTS

Compared with NIV, HFNC reduced the risk of respiratory failure by 8.4%, 95% CI 6.2-12.8%. Even though the rate of re-intubation was lower in the HFNC group versus in the NIV group, no statistical significance was observed (11.6% vs 16.6%; difference 5%, 95% CI 2.5%-8.2%). In 48-h periods and 72 h after extubation, the mean PaO2 /FIO2 significantly increased in the HFNC group compared with the NIV group. Both groups had low dyspnea levels 72 h after extubation. No difference was detected between the groups in breathing frequency. In addition, the 2 groups had no significant difference in ICU and hospital length of stay. The HFNC and NIV groups had comparable hospital mortality rates. The multivariable logistic regression analysis revealed the presence of severe obesity, comorbidities, a higher severity score, and hypercapnia remained as factors associated with an increased risk of re-intubation.

CONCLUSIONS

Postextubation application of HFNC may prevent respiratory failure in patients who are obese. (ClinicalTrials.gov registration NCT04035351.).

Non-rebreather mask and low-flow nasal cannula vs high-flow nasal cannula in severe COVID-19 pneumonia in the emergency department

BACKGROUND

To assess the effectiveness of non-rebreather mask combined with low-flow nasal cannula (NRB + NC) compared to high-flow nasal cannula (HFNC) in improving oxygenation in patients with COVID-19-related hypoxemic respiratory failure (HRF).

METHODS

This retrospective study was conducted in emergency departments of two tertiary hospitals from June 1 to August 31, 2021. Consecutive patients aged >18 years admitted for COVID-19-related HRF (World Health Organization criteria: confirmed COVID-19 pneumonia with respiratory rate > 30 breaths/min, severe respiratory distress, or peripheral oxygen saturation < 90% on room air) requiring NRB + NC or HFNC were screened for enrollment. Primary outcome was improvement of partial pressure arterial oxygen (PaO₂) at two hours. Secondary outcomes were intubation rate, ventilator-free days, hospital length of stay, and 28-day mortality. Data were analyzed using linear regression with inverse probability of treatment weighting (IPTW) based on propensity score.

RESULTS

Among the 110 patients recruited, 52 (47.3%) were treated with NRB + NC, and 58 (52.7%) with HFNC. There were significant improvements in patients' PaO₂, PaO₂/F_IO2 ratio, and respiratory rate two hours after the initiation of NRB + NC and HFNC. Comparing the two groups, after IPTW adjustment, there were no statistically significant differences in PaO₂ improvement (adjusted mean ratio [MR] 2.81; 95% CI -5.82 to 11.43; p = .524), intubation rate (adjusted OR 1.76; 95% CI 0.44 to 6.92; p = .423), ventilator-free days (adjusted MR 0.00; 95% CI -8.84 to 8.85; p = .999), hospital length of stay (adjusted MR 3.04; 95% CI -2.62 to 8.69; p = .293), and 28-day mortality (adjusted OR 0.68; 95% CI 0.15 to 2.98; p = .608).

CONCLUSION

HFNC may be beneficial in COVID-19 HRF. NRB + NC is a viable alternative, especially in resource-limited settings, given similar improvement in oxygenation at two hours, and no significant differences in long-term outcomes. The effectiveness of NRB + NC needs to be investigated by a powered randomized controlled trial.

Clinical practice guidelines: management of severe bronchiolitis in infants under 12 months old admitted to a pediatric critical care unit

PURPOSE

We present guidelines for the management of infants under 12 months of age with severe bronchiolitis with the aim of creating a series of pragmatic recommendations for a patient subgroup that is poorly individualized in national and international guidelines.

METHODS

Twenty-five French-speaking experts, all members of the Groupe Francophone de Réanimation et Urgence Pédiatriques (French-speaking group of paediatric intensive and emergency care; GFRUP) (Algeria, Belgium, Canada, France, Switzerland), collaborated from 2021 to 2022 through teleconferences and face-to-face meetings. The guidelines cover five areas: (1) criteria for admission to a pediatric critical care unit, (2) environment and monitoring, (3) feeding and hydration, (4) ventilatory support and (5) adjuvant therapies. The questions were written in the Patient-Intervention-Comparison-Outcome (PICO) format. An extensive Anglophone and Francophone literature search indexed in the MEDLINE database via PubMed, Web of Science, Cochrane and Embase was performed using pre-established keywords. The texts were analyzed and classified according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. When this method did not apply, an expert opinion was given. Each of these recommendations was voted on by all the experts according to the Delphi methodology.

RESULTS

This group proposes 40 recommendations. The GRADE methodology could be applied for 17 of them (3 strong, 14 conditional) and an expert opinion was given for the remaining 23. All received strong approval during the first round of voting.

CONCLUSION

These guidelines cover the different aspects in the management of severe bronchiolitis in infants admitted to pediatric critical care units. Compared to the different ways to manage patients with severe bronchiolitis described in the literature, our original work proposes an overall less invasive approach in terms of monitoring and treatment.

High-flow nasal cannula and non-invasive mechanical ventilation in pediatric asthma exacerbation: two-year prospective observational study in intensive care

BACKGROUND

Asthma is a common cause of admission to the pediatric intensive care unit (PICU). We described and analyzed the therapies applied to children admitted to a tertiary PICU because of asthma. Later, we evaluated high-flow nasal cannula (HFNC) use in these patients and compared their evolution and complications with those who received non-invasive ventilation.

METHODS

We conducted a prospective observational study (October 2017-October 2019). Collected data: epidemiological, clinical, respiratory support therapy needed, complementary tests, and PICU and hospital stay. Patients were divided into three groups: (1) only HFNC; (2) HFNC and non-invasive mechanical ventilation (NIMV); and (3) only NIMV.

RESULTS

Seventy-six patients were included (39 female). The median age was 2 years and 1 month. The median pulmonary score was 5. The median PICU stay was 3 days, and the hospital stay was 6 days. Children with HNFC only (56/76) had fewer PICU days (p = 0.025) and did not require NIMV (6/76). Children with HFNC had a higher oxygen saturation/fraction of inspired oxygen ratio ratio (p = 0.025) and lower PCO2 (p = 0.032). In the group receiving both therapies (14/76), NIMV was used first in all cases. No epidemiologic or clinical differences were found among groups.

CONCLUSION

HFNC was a safe approach that did not increase the number of PICU or hospital days. On admission, normal initial blood gases and the absence of high oxygen requirements were useful in selecting responders to HFNC. Further randomized and multicenter clinical trials are needed to verify these data.

Choice of respiratory therapy for COVID-19 patients with acute hypoxemic respiratory failure: a retrospective case series study

Background

In the treatment of acute hypoxemic respiratory failure (AHRF) due to coronavirus 2019 (COVID-19), physicians choose respiratory management ranging from low-flow oxygen therapy to more invasive methods, depending on the severity of the patient's symptoms. Recently, the ratio of oxygen saturation (ROX) index has been proposed as a clinical indicator to support the decision for either high-flow nasal cannulation (HFNC) or mechanical ventilation (MV). However, the reported cut-off value of the ROX index ranges widely from 2.7 to 5.9. The objective of this study was to identify indices to achieve empirical physician decisions for MV initiation, providing insights to shorten the delay from HFNC to MV. We retrospectively analyzed the ROX index 6 hours after initiating HFNC and lung infiltration volume (LIV) calculated from chest computed tomography (CT) images in COVID-19 patients with AHRF.

Methods

We retrospectively analyzed the data for 59 COVID-19 patients with AHRF in our facility to determine the cut-off value of the ROX index for respiratory therapeutic decisions and the significance of radiological evaluation of pneumonia severity. The physicians chose either HFNC or MV, and the outcomes were retrospectively analyzed using the ROX index for initiating HFNC. LIV was calculated using chest CT images at admission.

Results

Among the 59 patients who required high-flow oxygen therapy with HFNC at admission, 24 were later transitioned to MV; the remaining 35 patients recovered. Four of the 24 patients in the MV group died, and the ROX index values of these patients were 9.8, 7.3, 5.4, and 3.0, respectively. These index values indicated that the ROX index of half of the patients who died was higher than the reported cut-off values of the ROX index, which range from 2.7-5.99. The cut-off value of the ROX index 6 hours after the start of HFNC, which was used to classify the management of HFNC or MV as a physician's clinical decision, was approximately 6.1. The LIV cut-off value on chest CT between HFNC and MV was 35.5%. Using both the ROX index and LIV, the cut-off classifying HFNC or MV was obtained using the equation, LIV = 4.26 × (ROX index) + 7.89. The area under the receiver operating characteristic curve, as an evaluation metric of the classification, improved to 0.94 with a sensitivity of 0.79 and specificity of 0.91 using both the ROX index and LIV.

Conclusion

Physicians' empirical decisions associated with the choice of respiratory therapy for HFNC oxygen therapy or MV can be supported by the combination of the ROX index and the LIV index calculated from chest CT images.

High-flow nasal cannula therapy with sequential noninvasive ventilation versus noninvasive ventilation alone as the initial ventilatory strategy in acute COPD exacerbations: study protocol for a randomized controlled trial

BACKGROUND

Noninvasive ventilation (NIV) is the recommended mode of ventilation used in acute respiratory failure secondary to an acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Recent data has shown that high-flow nasal cannula (HFNC) treatment can be an alternative for patients with hypercapnic respiratory failure. The purpose of this study is to evaluate HFNC with sequential NIV versus NIV alone as the initial ventilatory strategy in AECOPD.

METHODS

This investigator-initiated, unblinded, single center, randomized controlled trial will be conducted in the emergency department, emergency intensive care unit, or respiratory intensive care unit of a tertiary-care urban teaching hospital. A total of 66 patients will be enrolled and randomized into the intervention group (HFNC with sequential NIV) or the control group (NIV group). The primary endpoint will be the mean difference in PaCO₂ from baseline to 24 h after randomization. Secondary endpoints include the mean difference in PaCO₂ from baseline to 6, 12, and 18 h, as well as the dyspnea score, overall discomfort score, rate of treatment failure, respiratory rate, rate of endotracheal intubation, length of hospital stay, and mortality.

DISCUSSION

Taking the advantages of both HFNC and NIV on AECOPD patients into account, we designed this clinical trial to investigate the combination of these ventilatory strategies. This trial will help us understand how HFNC with sequential NIV compares to NIV alone in treating AECOPD patients.

TRIAL REGISTRATION

ChiCTR2100054809.

Noninvasive Respiratory Support Effects on Sighs in Preterm Infants by Electrical Impedance Tomography

OBJECTIVE

To evaluate differences regarding sigh frequency between noninvasive respiratory support types and to assess regional ventilation distribution, delta Z, and end-expiratory lung impedance differences before and after sighs.

METHODS

Very low-birth-weight infants with gestational ages less than 32 wk were included in the study. Participants were split into two groups: those receiving continuous positive airway pressure and infants receiving high-flow nasal cannula therapy.

RESULTS

The study enrolled 30 infants. The high-flow nasal cannula therapy group had more sighs per 10-min period than infants receiving continuous positive airway pressure (p = 0.016). Ventilation distribution was similar in the anterior and right ventilation distribution compartments pre- and post-sigh (46.30% vs. 45.68% and 54.27% vs. 55.26%, respectively). No statistically significant increase in end-expiratory lung impedance or delta Z was observed in global or separate lung regions (p > 0.05).

CONCLUSION

The study has demonstrated that sighs are more frequent in infants receiving high-flow nasal cannula respiratory support compared to continuous positive airway pressure. Spontaneously occurring sighs on noninvasive respiratory support due to respiratory distress syndrome (RDS) do not increase end-expiratory lung impedance or alter delta Z, and appear to have limited clinical significance.

TRIAL REGISTRATION

Prospectively registered at www.

CLINICALTRIALS

gov , reg. No. NCT04542096, reg. date 01/09/2020.

Systematic review and meta-analysis of efficacy and safety of continuous positive airways pressure versus high flow oxygen cannula in acute bronchiolitis

INTRODUCTION

There are a trend towards increasing use of High-Flow Nasal Cannula (HFNC), outside of paediatric intensive care unit. Give this trend is necessary to update the actual evidence and to assess available published literature to determinate the efficacy of HFNC over Continuous Positive Air Pressure (CPAP) as treatment for children with severe bronchiolitis.

METHODS

We searched MEDLINE, EMBASE, LILACS, and COCHRANE Central, and gray literature in clinical trials databases ( www.

CLINICALTRIALS

gov ), from inception to June 2022. The inclusion criteria for the literature were randomized clinical trials (RCTs) that included children < 2 years old, with acute moderate or severe bronchiolitis. All study selection and data extractions are performed independently by two reviewers.

RESULTS

The initial searches including 106 records. Only five randomized controlled trial that met the inclusion criteria were included in meta-analysis. The risk of invasive mechanical ventilation was not significantly different in CPAP group and HFNC group [OR: 1.18, 95% CI (0.74, 1.89), I² = 0%] (very low quality). The risk of treatment failure was less significantly in CPAP group than HFNC group [OR: 0.51, 95% CI (0.36, 0.75), I² = 0%] (very low quality).

CONCLUSION

In conclusion, there was no significant difference between HFNC and CPAP in terms of risk of invasive mechanical ventilation. CPAP reduces de risk of therapeutic failure with a highest risk of non severe adverse events. More trials are needed to confirm theses results.