Nasal pillow noninvasive ventilation versus high-flow nasal therapy after extubation in surgical intensive care patients: A propensity-matched cohort study

Objective

To evaluate the tolerability and efficacy of nasal pillow-noninvasive ventilation (NP-NIV) compared with high-flow nasal therapy (HFNT) in postsurgical patients.

Methods

This propensity score-matched retrospective study enrolled postoperative patients that received NP-NIV (NP-NIV group) or HFNT (HFNT group) in the intensive care unit. Data were collected from their medical records and the tolerability and respiratory status before and after extubation were compared between the two groups.

Results

The study enrolled 83 patients in the NP-NIV group and 27 patients in the HFNT group. After propensity score matching, there were 19 patients in each group. After matching, there were no significant differences in the baseline demographic and clinical characteristics before extubation. The tolerability was similar in both groups. When the NP-NIV group was compared with the HFNT group, the respiratory rate was significantly lower (median 16 [interquartile range, 14–17] versus median 19 [interquartile range, 18–26], respectively) and the partial pressure of arterial oxygen/fraction of inspired oxygen ratio was significantly higher (median 205 [174–256] versus median 155 [130–192], respectively) at 1 h after extubation.

Conclusion

NP-NIV was equally well tolerated and provided better respiratory support than HFNT in postsurgical patients.

Reversibility of Hypercapnia after an Acute Exacerbation of COPD

Background

After an episode of hypercapnic AECOPD, some patients show reversible, prolonged or persistent hypercapnic respiratory failure. However, at the time of patient discharge, it is uncertain whether patients will remain hypercapnic or may return to a physiologic gas status.

Methods

Data were retrospectively collected from COPD patients with an acute hypercapnic exacerbation (AECOPD). Out of 143 total COPD inpatients, complete data set was available for 82 patients in stable condition. According to the first available capillary or arterial pCO₂, patients were divided into those with persistent hypercapnia (PHG) and those with reversible hypercapnia.

Results

In this study, 51% of patients with acute hypercapnic AECOPD and follow-up (FUP) visits developed normocapnia after a time period of several weeks. These patients were characterized by lower carbon dioxide partial pressure (PaCO₂), HCO₃⁻, and BE levels prior to the AECOPD event, at discharge and at FUP. pH was higher at discharge and FUP in this group. Greater disease severity and lower forced vital capacity were prominent in patients with PHG. Binary logistic regression revealed GOLD D and higher PaCO₂ at discharge as predicting factors for PHG.

Conclusions

A large percentage of patients has prolonged hypercapnia following acute hypercapnic COPD exacerbation. The risk profile of patients with irreversible hypercapnia should be carefully evaluated following AECOPD in order to choose selected patients for home-noninvasive ventilation.

Mechanical Ventilation and Respiratory Support in the Pediatric Intensive Care Unit

Children admitted to the pediatric intensive care unit often require respiratory support for the treatment of respiratory distress and failure. Respiratory support comprises both noninvasive modalities (ie, heated humidified high-flow nasal cannula, continuous positive airway pressure, bilevel positive airway pressure, negative pressure ventilation) and invasive mechanical ventilation. In this article, we review the various essential elements and considerations involved in the planning and application of respiratory support in the treatment of the critically ill children.

Usefulness of P0.1 in the Follow-Up of Individuals With Air Trapping and Home Noninvasive Ventilation and CPAP

BACKGROUND

The ventilatory mechanics of patients with COPD and obesity-hypoventilation syndrome (OHS) are changed when there is air trapping and auto-PEEP, which increase respiratory effort. P0.1 measures the ventilatory drive and, indirectly, respiratory effort. The aim of the study was to measure P0.1 in subjects with COPD or OHS on treatment with positive pressure and to analyze their changes in P0.1 after treatment.

METHODS

With a prospective design, subjects with COPD and OHS were studied in whom positive airway pressure was applied in their treatment. P0.1 was determined at study inclusion and after 6 months of treatment.

RESULTS

A total of 88 subjects were analyzed: 56% were males, and the mean age of 65 ± 9 y old. Fifty-four (61%) had OHS, and 34 (39%) had COPD. Fifty (56%) had air trapping, with an initial P0.1 value of 3.0 ± 1.3 cm H2O compared with 2.1 ± 0.7 cm H2O for subjects who did not have air trapping (P = .001). After 6 months of treatment, subjects who had air trapping had similar P0.1 as those who did not: 2.3 ± 1.1 and 2.1 ± 1 cm H2O, respectively (P = .53). In subjects with COPD, initial P0.1 was 2.9 ± 1.4 cm H2O and at 6 months 2.2 ± 1.1 cm H2O (P = .02). In subjects with OHS, initial P0.1 was 2.4 ± 1.1 cm H2O and at 6 months 2.2 ± 1.0 cm H2O (P = .28).

CONCLUSIONS

COPD and air trapping were associated with greater P0.1 as a marker of respiratory effort. A decrease in P0.1 indicates less respiratory effort after treatment.

Respiratory support strategy in adults with acute hypoxemic respiratory failure: a systematic review and network meta-analysis

Introduction

Network meta-analyses (NMAs) of respiratory management strategies for acute hypoxemic respiratory failure (AHRF) have been reported, but no previous study has compared noninvasive ventilation (NIV), high-flow nasal oxygen (HFNO), standard oxygenation therapy (SOT), and invasive mechanical ventilation (IMV) for de novo AHRF. Therefore, we conducted an NMA to assess the effectiveness of these four respiratory strategies in patients with de novo AHRF.

Methods

The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and Ichushi databases were searched. Studies including adults aged ≥18 years with AHRF and RCTs that compared two different oxygenation techniques (SOT, NIV, HFNO, or IMV) were selected. A frequentist-based approach with multivariate random-effects meta-analysis was used. The outcomes were mortality and intubation rates.

Results

Among the 14,263 records initially identified, 25 studies (3302 patients) were included. In the analysis of mortality, compared to SOT, NIV (risk ratio [RR], 0.76; 95% confidence interval [CI], 0.61–0.95) reduced mortality; however, IMV (RR, 1.01; 95% CI, 0.57–1.78) and HFNO (RR, 0.89; 95% CI, 0.66–1.20) did not. For assessments of the intubation incidence, compared to SOT, NIV use (RR, 0.63; 95% CI, 0.51–0.79) was associated with a reduction in intubation, but HFNO (RR, 0.82; 95% CI, 0.61–1.11) was not significant.

Conclusions

Our NMA demonstrated that only NIV showed clinical benefits compared with SOT as an initial respiratory strategy for de novo AHRF. Further investigation, especially comparison with HFNO, is warranted.

Trial registration

PROSPERO (registration number: CRD42020213948, 11/11/2020).

Supplementary Information

The online version contains supplementary material available at 10.1186/s40981-022-00525-4.

Proposals from a French expert panel for respiratory care in ALS patients

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive diaphragm weakness and deteriorating lung function. Bulbar involvement and cough weakness contribute to respiratory morbidity and mortality. ALS-related respiratory failure significantly affects quality of life and is the leading cause of death. Non-invasive ventilation (NIV), which is the main recognized treatment for alleviating the symptoms of respiratory failure, prolongs survival and improves quality of life. However, the optimal timing for the initiation of NIV is still a matter of debate. NIV is a complex intervention. Multiple factors influence the efficacy of NIV and patient adherence. The aim of this work was to develop practical evidence-based advices to standardize the respiratory care of ALS patients in French tertiary care centres.

METHODS

For each proposal, a French expert panel systematically searched an indexed bibliography and prepared a written literature review that was then shared and discussed. A combined draft was prepared by the chairman for further discussion. All of the proposals were unanimously approved by the expert panel.

RESULTS

The French expert panel updated the criteria for initiating NIV in ALS patients. The most recent criteria were established in 2005. Practical advice for NIV initiation were included and the value of each tool available for NIV monitoring was reviewed. A strategy to optimize NIV parameters was suggested. Revisions were also suggested for the use of mechanically assisted cough devices in ALS patients.

CONCLUSION

Our French expert panel proposes an evidence-based review to update the respiratory care recommendations for ALS patients in daily practice.

Early prolonged prone position in noninvasively ventilated patients with SARS-CoV-2-related moderate-to-severe hypoxemic respiratory failure: clinical outcomes and mechanisms for treatment response in the PRO-NIV study

Background

Whether prone position (PP) improves clinical outcomes in COVID-19 pneumonia treated with noninvasive ventilation (NIV) is unknown. We evaluated the effect of early PP on 28-day NIV failure, intubation and death in noninvasively ventilated patients with moderate-to-severe acute hypoxemic respiratory failure due to COVID-19 pneumonia and explored physiological mechanisms underlying treatment response.

Methods

In this controlled non-randomized trial, 81 consecutive prospectively enrolled patients with COVID-19 pneumonia and moderate-to-severe (paO2/FiO2 ratio < 200) acute hypoxemic respiratory failure treated with early PP + NIV during Dec 2020–May 2021were compared with 162 consecutive patients with COVID-19 pneumonia matched for age, mortality risk, severity of illness and paO2/FiO2 ratio at admission, treated with conventional (supine) NIV during Apr 2020–Dec 2020 at HUMANITAS Gradenigo Subintensive Care Unit, after propensity score adjustment for multiple baseline and treatment-related variables to limit confounding. Lung ultrasonography (LUS) was performed at baseline and at day 5. Ventilatory parameters, physiological dead space indices (DSIs) and circulating inflammatory and procoagulative biomarkers were monitored during the initial 7 days.

Results

In the intention-to-treat analysis. NIV failure occurred in 14 (17%) of PP patients versus 70 (43%) of controls [HR = 0.32, 95% CI 0.21–0.50; p < 0.0001]; intubation in 8 (11%) of PP patients versus 44 (30%) of controls [HR = 0.31, 95% CI 0.18–0.55; p = 0.0012], death in 10 (12%) of PP patients versus 59 (36%) of controls [HR = 0.27, 95% CI 0.17–0.44; p < 0.0001]. The effect remained significant within different categories of severity of hypoxemia (paO2/FiO2 < 100 or paO2/FiO2 100–199 at admission). Adverse events were rare and evenly distributed. Compared with controls, PP therapy was associated with improved oxygenation and DSIs, reduced global LUS severity indices largely through enhanced reaeration of dorso-lateral lung regions, and an earlier decline in inflammatory markers and D-dimer. In multivariate analysis, day 1 CO2 response outperformed O2 response as a predictor of LUS changes, NIV failure, intubation and death.

Conclusion

Early prolonged PP is safe and is associated with lower NIV failure, intubation and death rates in noninvasively ventilated patients with COVID-19-related moderate-to-severe hypoxemic respiratory failure. Early dead space reduction and reaeration of dorso-lateral lung regions predicted clinical outcomes in our study population.

Clinical trial registration

ISRCTN23016116. Retrospectively registered on May 1, 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-03937-x.

Efficacy, dose-response, and aerosol delivery of dry powder synthetic lung surfactant treatment in surfactant-deficient rabbits and premature lambs

BACKGROUND

Dry powder (DP) synthetic lung surfactant may be an effective means of noninvasive delivery of surfactant therapy to premature infants supported with nasal continuous positive airway pressure (nCPAP) in low-resource settings.

METHODS

Four experimental DP surfactant formulations consisting of 70% of phospholipids (DPPC:POPG 7:3), 3% Super Mini-B (SMB) or its sulfur-free derivate B-YL as SP-B peptide mimic, 25% of lactose or trehalose as excipient, and 2% of NaCl were formulated using spray drying. In vitro surface activity was confirmed with captive bubble surfactometry. Surfactant particle size was determined with a cascade impactor and inhaled dose was quantified using a spontaneously breathing premature lamb lung model supported with CPAP. In vivo surfactant efficacy was demonstrated in three studies. First, oxygenation and lung compliance were monitored after intratracheal instillation of resuspended DP surfactant in intubated, ventilated, lavaged, surfactant-deficient juvenile rabbits. In dose-response studies, ventilated, lavaged, surfactant-deficient rabbits received 30, 60, 120 or 240 mg/kg of DP B-YL:Lactose or B-YL:Trehalose surfactant by aerosol delivery with a low flow aerosol chamber via their endotracheal tube. Noninvasive aerosolization of DP B-YL:Trehalose surfactant via nasal prongs was tested in spontaneous breathing premature lambs supported with nCPAP. Intratracheal administration of 200 mg/kg of Curosurf®, a liquid porcine surfactant, was used as a positive control.

RESULTS

Mass median aerosol diameter was 3.6 μm with a geometric standard deviation of 1.8. All four experimental surfactants demonstrated high surface efficacy of intratracheal instillation of a bolus of ~ 100 mg/kg of surfactant with improvement of oxygenation and lung compliance. In the dose-response studies, rabbits received incremental doses of DP B-YL:Lactose or B-YL:Trehalose surfactant intratracheally and showed an optimal response in oxygenation and lung function at a dose of 120-240 mg/kg. Aerosol delivery via nasal prongs of 1 or 2 doses of ~ 100 mg/kg of B-YL:Trehalose surfactant to premature lambs supported with nCPAP resulted in stabilization of spontaneous breathing and oxygenation and lung volumes comparable to the positive control.

CONCLUSION

These studies confirm the clinical potential of DP synthetic lung surfactant with B-YL peptide as a SP-B mimic to alleviate surfactant deficiency when delivered as a liquid bolus or as an aerosol.

Effectiveness of CPAP vs. Noninvasive Ventilation Based on Disease Severity in Obesity Hypoventilation Syndrome and Concomitant Severe Obstructive Sleep Apnea

RATIONALE

Obesity hypoventilation syndrome (OHS) with concomitant severe obstructive sleep apnea (OSA) is treated with CPAP or noninvasive ventilation (NIV) during sleep. NIV is costlier, but may be advantageous because it provides ventilatory support. However, there are no long-term trials comparing these treatment modalities based on OHS severity.

OBJECTIVE

To determine if CPAP have similar effectiveness when compared to NIV according to OHS severity subgroups.

METHODS

Post hoc analysis of the Pickwick randomized clinical trial in which 215 ambulatory patients with untreated OHS and concomitant severe OSA, defined as apnoea-hypopnea index (AHI)≥30events/h, were allocated to NIV or CPAP. In the present analysis, the Pickwick cohort was divided in severity subgroups based on the degree of baseline daytime hypercapnia (PaCO₂ of 45-49.9 or ≥50mmHg). Repeated measures of PaCO₂ and PaO₂ during the subsequent 3 years were compared between CPAP and NIV in the two severity subgroups. Statistical analysis was performed using linear mixed-effects model.

RESULTS

204 patients, 97 in the NIV group and 107 in the CPAP group were analyzed. The longitudinal improvements of PaCO₂ and PaO₂ were similar between CPAP and NIV based on the PaCO₂ severity subgroups.

CONCLUSION

In ambulatory patients with OHS and concomitant severe OSA who were treated with NIV or CPAP, long-term NIV therapy was similar to CPAP in improving awake hypercapnia, regardless of the severity of baseline hypercapnia. Therefore, in this patient population, the decision to prescribe CPAP or NIV cannot be solely based on the presenting level of PaCO₂.

Accuracy evaluation of mainstream and sidestream end-tidal carbon dioxide monitoring during noninvasive ventilation: a randomized crossover trial (MASCAT-NIV trial)

Background

The end-tidal partial pressure of carbon dioxide (P_ETCO₂) can be used to estimate the arterial partial pressure of carbon dioxide (PaCO₂) in patients who undergo mechanical ventilation via endotracheal intubation. However, no reliable method for measuring P_ETCO₂ during noninvasive ventilation (NIV) has been established. The purpose of this study was to evaluate the correlation and agreement between PaCO₂ and P_ETCO₂ measured by these two methods and to compare them in patients who underwent NIV after extubation.

Methods

This study was a randomized, open-label, crossover trial in a mixed intensive care unit. We included patients who were planned for NIV after extubation and for whom the difference between P_ETCO₂ and PaCO₂ was ≤ 5 mmHg. We compared mainstream capnography using an inner cup via face mask (the novel method) with sidestream capnography (the previous method) during NIV. The relationships between PaCO₂ and P_ETCO₂ were evaluated by computing the Pearson correlation coefficient, and the agreement between PaCO₂ and P_ETCO₂ was estimated using the Bland–Altman method.

Results

From April 2020 to October 2021, 60 patients were included to the study. PaCO₂ and P_ETCO₂ were well correlated in both methods (the novel methods: r = 0.92, P < 0.001; the previous method: r = 0.79, P < 0.001). Mean bias between PaCO₂ and P_ETCO₂ measured using the novel method was 2.70 (95% confidence interval [CI], 2.15–3.26) mmHg with 95% limits of agreement (LoA) ranging from − 1.61 to 7.02 mmHg, similar to the result of measurement during SBT (mean bias, 2.51; 95% CI, 2.00–3.02; 95% LoA, − 1.45 to 6.47 mmHg). In contrast, measurement using the previous method demonstrated a larger difference (mean bias, 6.22; 95% CI, 5.22–7.23; 95% LoA, − 1.54 to 13.99 mmHg).

Conclusion

The current study demonstrated that the novel P_ETCO₂ measurement was superior to the previous method for PaCO₂ prediction. During NIV, the novel method may collect as sufficient exhalation sample as during intubation. Continuous P_ETCO₂ measurement combined with peripheral oxygen saturation monitoring is expected to be useful for early recognition of respiratory failure among high-risk patients after extubation.

Trial registration UMIN-CTR UMIN000039459. Registered February 11, 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-022-00603-w.

Non Invasive Ventilation's Effectiveness (NIV) in Patients with Interstitial Lung Disease and Hypercapnic Respiratory Failure

Background

The therapeutic options for patients with interstitial lung disease (ILD) are limited. On the other hand, the role of noninvasive ventilation (NIV) in ILD management is not clear. This study investigated the effect of nighttime NIV in hypercapnic ILD patients.

Materials and Methods

In this unblinded randomized clinical trial, we included a total of 20 ILD patients admitted in a specialized center with hypoxia, PaCO₂>45, and HCO₃>27. Participants were randomly allocated into two groups; intervention (nighttime NIV plus standard treatment) and control (standard treatment). The severity of dyspnea and the quality of life (QoL) was evaluated at beginning of the trial and after 30 days through Modified medical research council (mMRC) dyspnea scale and the SF-36 health survey questionnaire. Paired or Wilcoxon Signed rank tests and independent samples t-test or Mann-Whiney U test were used for between and within groups analyses, respectively.

Results

The mean age of 20 patients enrolled was 62.57±6.67 and 40% were male. Although, a clinical significant improvement of dyspnea was detected in NIV group (P=0.046) after intervention, it was not statistically different from control group. Significant improvement was observed in physical functioning (P<0.001), social functioning (P=0.004) and pain (P=0.003) detected after 30 days in NIV group and the observed improvement in QoL was significantly higher than control group for physical functioning (P=0.042) and general health (0.049).

Conclusion

Our results suggest NIV treatment in patients with ILD and hypercapnic respiratory failure could be advised in order to improve physical functioning.

Helmet noninvasive ventilation for COVID-19 patients (Helmet-COVID): statistical analysis plan for a randomized controlled trial

BACKGROUND

Noninvasive respiratory support is frequently needed for patients with acute hypoxemic respiratory failure due to coronavirus disease 19 (COVID-19). Helmet noninvasive ventilation has multiple advantages over other oxygen support modalities but data about effectiveness are limited.

METHODS

In this multicenter randomized trial of helmet noninvasive ventilation for COVID-19 patients, 320 adult ICU patients (aged ≥14 years or as per local standards) with suspected or confirmed COVID-19 and acute hypoxemic respiratory failure (ratio of arterial oxygen partial pressure to fraction of inspired oxygen < 200 despite supplemental oxygen with a partial/non-rebreathing mask at a flow rate of 10 L/min or higher) will be randomized to helmet noninvasive ventilation with usual care or usual care alone, which may include mask noninvasive ventilation, high-flow nasal oxygen, or standard oxygen therapy. The primary outcome is death from any cause within 28 days after randomization. The trial has 80% power to detect a 15% absolute risk reduction in 28-day mortality from 40 to 25%. The primary outcome will be compared between the helmet and usual care group in the intention-to-treat using the chi-square test. Results will be reported as relative risk  and 95% confidence interval. The first patient was enrolled on February 8, 2021. As of August 1, 2021, 252 patients have been enrolled from 7 centers in Saudi Arabia and Kuwait.

DISCUSSION

We developed a detailed statistical analysis plan to guide the analysis of the Helmet-COVID trial, which is expected to conclude enrollment in November 2021.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04477668 . Registered on July 20, 2020.

Noninvasive Ventilation and Oxygenation Strategies

Noninvasive ventilation (NIV) provides respiratory support without the use of invasive ventilation with techniques that do not bypass the upper airway. NIV is particularly attractive given its associated reduced risk of complications associated with intubation. Available NIV modes include nasal cannula, simple mask, nonrebreather, high flow nasal cannula, continuous positive airway pressure (CPAP), and bilevel positive airway pressure. Acute exacerbation of COPD, cardiogenic pulmonary edema, and COVID-19 are conditions for which NIV has shown to be beneficial, whereas there is no consensus among the use of NIV in trauma patients and ARDS.

Efficacy prediction of noninvasive ventilation failure based on the stacking ensemble algorithm and autoencoder

Background

Early prediction of noninvasive ventilation failure is of great significance for critically ill ICU patients to escalate or change treatment. Because clinically collected data are highly time-series correlated and have imbalanced classes, it is difficult to accurately predict the efficacy of noninvasive ventilation for severe patients. This paper aims to precisely predict the failure probability of noninvasive ventilation before or in the early stage (1–2 h) of using it on patients and to explain the correlation of the predicted results.

Methods

In this paper, we proposed a SMSN model (stacking and modified SMOTE algorithm of prediction of noninvasive ventilation failure). In the feature generation stage, we used an autoencoder algorithm based on long short-term memory (LSTM) to automatically extract time series features. In the modelling stage, we adopted a modified SMOTE algorithm to address imbalanced classes, and three classifiers (logistic regression, random forests, and Catboost) were combined with the stacking ensemble algorithm to achieve high prediction accuracy.

Results

Data from 2495 patients were used to train the SMSN model. Among them, 80% of 2495 patients (1996 patients) were randomly selected as the training set, and 20% of these patients (499 patients) were chosen as the testing set. The F1 of the proposed SMSN model was 79.4%, and the accuracy was 88.2%. Compared with the traditional logistic regression algorithm, the F1 and accuracy were improved by 4.7% and 1.3%, respectively.

Conclusions

Through SHAP analysis, oxygenation index, pH and H1FIO₂ collected after 1 h of noninvasive ventilation were the most relevant features affecting the prediction.

Outcomes after Prolonged Weaning in Chronic Obstructive Pulmonary Disease Patients: Data from the German WeanNet Initiative

BACKGROUND

The outcome of prolonged weaning in COPD patients is still unclear.

METHODS

A subgroup analysis of 2,937 COPD patients (median: age 69 years, 5 comorbidities, 43% female) from the entire WeanNet cohort of specialized German weaning centers previously published (N = 11,424) was performed.

RESULTS

Weaning outcomes were as follows: successful weaning without subsequent long-term noninvasive ventilation (NIV): N = 900; 30.6%; successful weaning with subsequent long-term NIV: N = 900; 30.6%; weaning failure with subsequent long-term invasive ventilation: N = 780; 26.6%; and death: N = 357; 12.2%. Most important predictors of mortality and weaning failure were advanced age and duration of mechanical ventilation in the transferring ICU, respectively. On discharge, the tracheostoma was closed in only 53% and 59% of patients with successful weaning not receiving and receiving long-term NIV, respectively. Unsuccessfully weaned patients were predominantly discharged home (20.5%) or to long-term care facilities (57.2%). Successfully weaned patients were predominantly discharged home (22.4%/35.9%: without/with NIV) and to rehabilitation (41.0%/43.1%: without/with NIV), respectively.

CONCLUSION

COPD forms an important subgroup of prolonged weaning patients. Following transfer from the ICU to a specialized weaning center, weaning is successful more than 60%. Importantly, both tracheostomy status and initial destination following discharge are highly dependent on the weaning outcome.

Noninvasive ventilation and high-flow nasal cannula in patients with acute hypoxemic respiratory failure by covid-19: a retrospective study of the feasebility, safety and outcomes

BACKGROUND

Noninvasive ventilation (NIV) and High-flow nasal cannula (HFNC) are the main forms of treatment for acute respiratory failure. This study aimed to evaluate the effect, safety, and applicability of the NIV and HFNC in patients with acute hypoxemic respiratory failure (AHRF) caused by COVID-19.

METHODS

In this retrospective study, we monitored the effect of NIV and HFNC on the SpO₂ and respiratory rate before, during, and after treatment, length of stay, rates of endotracheal intubation, and mortality in patients with AHRF caused by COVID-19. Additionally, data regarding RT-PCR from physiotherapists who were directly involved in assisting COVID-19 patients and non-COVID-19.

RESULTS

62.2% of patients were treated with HFNC. ROX index increased during and after NIV and HFNC treatment (P < 0.05). SpO₂ increased during NIV treatment (P < 0.05), but was not maintained after treatment (P = 0.17). In addition, there was no difference in the respiratory rate during or after the NIV (P = 0.95) or HFNC (P = 0.60) treatment. The mortality rate was 35.7% for NIV vs 21.4% for HFNC (P = 0.45), while the total endotracheal intubation rate was 57.1% for NIV vs 69.6% for HFNC (P = 0.49). Two adverse events occurred during treatment with NIV and eight occurred during treatment with HFNC. There was no difference in the physiotherapists who tested positive for SARS-CoV-2 directly involved in assisting COVID-19 patients and non-COVID-19 ones (P = 0.81).

CONCLUSION

The application of NIV and HFNC in the critical care unit is feasible and associated with favorable outcomes. In addition, there was no increase in the infection of physiotherapists with SARS-CoV-2.

Motor neuron, peripheral nerve, and neuromuscular junction disorders

In amyotrophic lateral sclerosis (ALS), Guillain-Barré syndrome (GBS), and neuromuscular junction disorders, three mechanisms may lead, singly or together, to respiratory emergencies and increase the disease burden and mortality: (i) reduced strength of diaphragm and accessory muscles; (ii) oropharyngeal dysfunction with possible aspiration of saliva/bronchial secretions/drink/food; and (iii) inefficient cough due to weakness of abdominal muscles. Breathing deficits may occur at onset or more often along the chronic course of the disease. Symptoms and signs are dyspnea on minor exertion, orthopnea, nocturnal awakenings, excessive daytime sleepiness, fatigue, morning headache, poor concentration, and difficulty in clearing bronchial secretions. The "20/30/40 rule" has been proposed to early identify GBS patients at risk for respiratory failure. The mechanical in-exsufflator is a device that assists ALS patients in clearing bronchial secretions. Noninvasive ventilation is a safe and helpful support, especially in ALS, but has some contraindications. Myasthenic crisis is a clinical challenge and is associated with substantial morbidity including prolonged mechanical ventilation and 5%-12% mortality. Emergency room physicians and consultant pulmonologists and neurologists must know such respiratory risks, be able to recognize early signs, and treat properly.

Outcome of patients with acute heart failure secondary to acute myocardial infarction treated with noninvasive mechanical ventilation

INTRODUCTION AND OBJECTIVES

Noninvasive ventilation (NIV) has been shown to reduce the rate of endotracheal intubation and mortality in patients with acute heart failure (AHF). However, patients with AHF secondary to acute coronary syndrome/acute myocardial infarction (ACS-AMI) have been excluded from many clinical trials. The purpose of this study was to compare the effectiveness of NIV between patients with AHF triggered by ACS-AMI and by other etiologies.

METHODS

Prospective cohort study of all patients with AHF treated with NIV admitted to the intensive care unit for a period of 20 years. Patients were divided according to whether they had ACS-AMI as the cause of the AHF episode. NIV failure was defined as the need for endotracheal intubation or death.

RESULTS

A total of 1009 patients were analyzed, 403 (40%) showed ACS-AMI and 606 (60%) other etiologies. NIV failure occurred in 61 (15.1%) in the ACS-AMI group and in 64 (10.6%) in the other group (P=.031), without differences in in-hospital mortality (16.6% and 14.9%, respectively; P=.478).

CONCLUSIONS

The presence of ACS-AMI as the triggering cause of AHF did not influence patients with acute respiratory failure requiring noninvasive respiratory support.

Noninvasive and invasive mechanical ventilation for neurologic disorders

Patients with acute neurologic injuries frequently require mechanical ventilation due to diminished airway protective reflexes, cardiopulmonary failure secondary to neurologic insults, or to facilitate gas exchange to precise targets. Mechanical ventilation enables tight control of oxygenation and carbon dioxide levels, enabling clinicians to modulate cerebral hemodynamics and intracranial pressure with the goal of minimizing secondary brain injury. In patients with acute spinal cord injuries, neuromuscular conditions, or diseases of the peripheral nerve, mechanical ventilation enables respiratory support under conditions of impending or established respiratory failure. Noninvasive ventilatory approaches may be carefully considered for certain disease conditions, including myasthenia gravis and amyotrophic lateral sclerosis, but may be inappropriate in patients with Guillain-Barré syndrome or when relevant contra-indications exist. With regard to discontinuing mechanical ventilation, considerable uncertainty persists about the best approach to wean patients, how to identify patients ready for extubation, and when to consider primary tracheostomy. Recent consensus guidelines highlight these and other knowledge gaps that are the focus of active research efforts. This chapter outlines important general principles to consider when initiating, titrating, and discontinuing mechanical ventilation in patients with acute neurologic injuries. Important disease-specific considerations are also reviewed where appropriate.

Gas conditioning during helmet noninvasive ventilation: effect on comfort, gas exchange, inspiratory effort, transpulmonary pressure and patient-ventilator interaction

Background

There is growing interest towards the use of helmet noninvasive ventilation (NIV) for the management of acute hypoxemic respiratory failure. Gas conditioning through heat and moisture exchangers (HME) or heated humidifiers (HHs) is needed during facemask NIV to provide a minimum level of humidity in the inspired gas (15 mg H₂O/L). The optimal gas conditioning strategy during helmet NIV remains to be established.

Methods

Twenty patients with acute hypoxemic respiratory failure (PaO₂/FiO₂ < 300 mmHg) underwent consecutive 1-h periods of helmet NIV (PEEP 12 cmH₂O, pressure support 12 cmH₂O) with four humidification settings, applied in a random order: double-tube circuit with HHs and temperature set at 34 °C (HH34) and 37 °C (HH37); Y-piece circuit with HME; double-tube circuit with no humidification (NoH). Temperature and humidity of inhaled gas were measured through a capacitive hygrometer. Arterial blood gases, discomfort and dyspnea through visual analog scales (VAS), esophageal pressure swings (ΔP_ES) and simplified pressure–time product (PTP_ES), dynamic transpulmonary driving pressure (ΔP_L) and asynchrony index were measured in each step.

Results

Median [IqR] absolute humidity, temperature and VAS discomfort were significantly lower during NoH vs. HME, HH34 and HH37: absolute humidity (mgH₂O/L) 16 [12–19] vs. 28 [23–31] vs. 28 [24–31] vs. 33 [29–38], p < 0.001; temperature (°C) 29 [28–30] vs. 30 [29–31] vs. 31 [29–32] vs 32. [31–33], p < 0.001; VAS discomfort 4 [2–6] vs. 6 [2–7] vs. 7 [4–8] vs. 8 [4–10], p = 0.03. VAS discomfort increased with higher absolute humidity (p < 0.01) and temperature (p = 0.007). Higher VAS discomfort was associated with increased VAS dyspnea (p = 0.001). Arterial blood gases, respiratory rate, ΔP_ES, PTP_ES and ΔP_L were similar in all conditions. Overall asynchrony index was similar in all steps, but autotriggering rate was lower during NoH and HME (p = 0.03).

Conclusions

During 1-h sessions of helmet NIV in patients with hypoxemic respiratory failure, a double-tube circuit with no humidification allowed adequate conditioning of inspired gas, optimized comfort and improved patient–ventilator interaction. Use of HHs or HME in this setting resulted in increased discomfort due to excessive heat and humidity in the interface, which was associated with more intense dyspnea.

Trail Registration Registered on clinicaltrials.gov (NCT02875379) on August 23rd, 2016.

Synchronized Nasal Intermittent Positive Pressure Ventilation

Avoiding MV is a critical goal in neonatal respiratory care. Different modes of noninvasive respiratory support beyond nasal CPAP, such as nasal intermittent positive pressure ventilation (NIPPV) and synchronized NIPPV (SNIPPV), may further reduce intubation rates. SNIPPV offers consistent benefits over nonsynchronized techniques such as a more efficient positive pressure transmission to the lung, an effective increase in transpulmonary pressure during ventilation, and a better stabilization of the chest wall during inspiration. This review discusses mechanisms of action, benefits and limitations of synchronized noninvasive ventilation, describes the different modes of synchronization, and analyzes properties and clinical results.

Nasal Intermittent Positive Pressure Ventilation for Neonatal Respiratory Distress Syndrome

Nasal or noninvaisve intermittent positive pressure ventilation (NIPPV) refers to well-established noninvasive respiratory support strategies combining a continuous distending pressure with intermittent pressure increases. Uncertainty remains regarding the benefits provided by the various devices and techniques used to generate NIPPV. Our included meta-analyses of trials comparing NIPPV with continuous positive airway pressure (CPAP) in preterm infants demonstrate that both primary and postextubation NIPPV are superior to CPAP to prevent respiratory failure leading to additional ventilatory support. This short-term benefit is associated with a reduction in bronchopulmonary dysplasia, but not with mortality. Benefits are greatest when ventilator-generated, synchronized NIPPV is used.

Respiratory failure after scoliosis correction surgery in patients with Prader-Willi syndrome: Two case reports

BACKGROUND

Sleep-disordered breathing, including hypoventilation and obstructive sleep apnea, is often observed in Prader-Willi syndrome (PWS). Particularly in adolescence, scoliosis causes a progressive restrictive pulmonary pattern, leading to hypoventilation, so timely corrective surgery is required. However, the effect is controversial. In addition, since mental retardation of PWS, patient effort-based respiratory tests may be less reliable. So far, no studies have accurately reported on the comparison of respiratory function before and after corrective surgery, and appropriate respiratory function measurement method in PWS.

CASE SUMMARY

We present two cases of adolescent PWS with typical characteristics, including obesity, mental retardation, and scoliosis. Two boys, aged 12 and 13, diagnosed with PWS, both underwent scoliosis correction surgery. Before and immediately after surgery, arterial blood tests showed no abnormalities and no respiratory symptoms occurred. However, after 6-7 mo, both patients complained of daytime sleepiness, difficulty sleeping at night, dyspnea on exertion, and showed cyanosis. Hypercapnia and hypoxia were confirmed by polysomnography and transcutaneous CO₂ monitoring during sleep and were diagnosed with obstructive sleep apnea and alveolar hypoventilation. It was corrected by nighttime noninvasive ventilation application and normal findings of arterial blood gas were maintained after 6-8 mo follow-up.

CONCLUSION

Even after scoliosis surgery, “periodic” monitoring of respiratory failure with an “objective” test method is needed for timely respiratory support.