Sleep apnea-related hypoxic burden as a predictor of pregnancy and neonatal outcome.

STUDY OBJECTIVES: To determine the clinical impact of sleep apnea-related hypoxic burden in pregnant women and neonates. METHODS: This is a secondary analysis of the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be (nuMoM2b) study. Hypoxia burden was calculated from the home sleep apnea test (HSAT) and defined as the total area under respiratory events. Logistic regression analysis assessed the relationship between hypoxia burden and pregnancy/neonatal outcomes. RESULTS: A total of 3006 subjects in the early term, and 2326 subjects in the middle term of pregnancy, had HSAT. A hypoxic burden greater than 6.8%min was present in 1740 at early term and associated with a higher risk of preeclampsia (odds ratio 1.297, 95 % confidence interval 1.032-1.630, p: 0.026) after adjusted by obstructive sleep apnea (OSA) severity. In the middle term, 1058 subjects had a hypoxia burden more than 11.8%min, which was a predictor for higher incidence of gestational diabetes (OR 1.795, 95 % CI 1.097-2.938, p: 0.020) and an Apgar <7 at 1 min (OR 1.446, 95 % CI 1.079-1.939, p: 0.012) after adjusted by obstructive sleep apnea (OSA) severity. After adjusted by oxygenation disturbance index, HB was not related with Apgar <7 at 1 min (p:0.565). CONCLUSIONS: The hypoxic burden is an independent predictor for preeclampsia and gestational diabetes and an Apgar <7 at 1 min.

The association between the effective apnea-hypopnea index and blood pressure reduction efficacy following CPAP/oxygen treatment.

BACKGROUND: The effect of sleep apnea treatment on reducing cardiovascular disease risk remains inconclusive. This study aims to assess if the effective apnea hypopnea index (eAHI), a measure of residual sleep apnea burden post-treatment, is a factor in determining blood pressure (BP) response to continuous positive airway pressure therapy. The eAHI integrates time on therapy, residual apnea, and % of sleep time untreated. METHODS: A secondary analysis of the Heart Biomarker Evaluation in Apnea Treatment (HeartBEAT) study, a randomized, controlled, parallel group assessment of continuous positive airway pressure (CPAP), oxygen and sleep hygiene. The Delta-AHI (▲AHI) was defined as the difference between baseline AHI and effective AHI at 12 weeks. Logistic and linear regression models estimated the predictors for nocturnal systolic BP change following sleep apnea therapy. RESULTS: One hundred and sixty-nine subjects with a mean age of 62.82 ± 6.99 years were included in the final analysis. Fifty subjects had ▲AHI ≤8/hour of sleep and 119 subjects were higher. After adjustment, baseline mean nighttime systolic blood pressure (OR 1.036, 95% CI 1.015-1.058, p: 0.001) and ▲AHI ≥8/hour (OR 2.406, 95% CI 1.116-5.185, p:0.025) were independent predictors for mean nighttime systolic blood pressure change >3 mm Hg. The higher effective AHI was negatively related with BNP (ß: -2.564, SE: 1.167, p: 0.029) and positively related with troponin change (ß: 0.703, SE: 0.256, p: 0.007). CONCLUSION: The ▲AHI was an independent predictor of the blood pressure response to sleep apnea treatment. REGISTER NUMBER: NCT01086800.

PEEP-Induced Lung Recruitment Maneuver Combined with Prone Position for ARDS: A Single-Center, Prospective, Randomized Clinical Trial.

Background: Prone position (PP) and the positive end-expiratory pressure (PEEP)-induced lung recruitment maneuver (LRM) are both efficient in improving oxygenation and prognosis in patients with ARDS. The synergistic effect of PP combined with PEEP-induced LRM in patients with ARDS remains unclear. We aim to explore the effects of PP combined with PEEP-induced LRM on prognosis in patients with moderate to severe ARDS and the predicting role of lung recruitablity. Methods: Patients with moderate to severe ARDS were consecutively enrolled. The patients were prospectively assigned to either the intervention (PP with PEEP-induced LRM) or control groups (PP). The clinical outcomes, respiratory mechanics, and electric impedance tomography (EIT) monitoring results for the two groups were compared. Lung recruitablity (recruitment-to-inflation ratio: R/I) was measured during the PEEP-induced LRM procedure and was used for predicting the response to LRM. Results: Fifty-eight patients were included in the final analysis, among which 28 patients (48.2%) received PEEP-induced LRM combined with PP. PEEP-induced LRM enhanced the effect of PP by a significant improvement in oxygenation (∆PaO2/FiO2 75.8 mmHg vs. 4.75 mmHg, p < 0.001) and the compliance of respiratory system (∆Crs, 2 mL/cmH2O vs. -1 mL/cmH2O, p = 0.02) among ARDS patients. Based on the EIT measurement, PP combined with PEEP-induced LRM increased the ventilation distribution mainly in the dorsal region (5.0% vs. 2.0%, p = 0.015). The R/I ratio was measured in 28 subjects. The higher R/I ratio was related to greater oxygenation improvement after LRM (Pearson's r = 0.4; p = 0.034). Conclusions: In patients with moderate to severe ARDS, PEEP-induced LRM combined with PP can improve oxygenation and dorsal ventilation distribution. R/I can be useful to predict responses to LRM.

Ventilatory ratio as a predictor for extubation failure in critical ill patients based on MIMIC-IV database (from 2008 to 2019).

Background: The predictive ability of the ventilatory ratio (VR) for extubation failure risk in critically ill patients on mechanical ventilation is unclear. This study aims to examine the predictive ability of VR for extubation failure risk. Methods: This retrospective study was based on the MIMIC-IV database. The MIMIC-IV database consists of the clinical information of patients who were admitted to the intensive care unit at the Beth Israel Deaconess Medical Center between 2008 and 2019. With extubation failure as the primary outcome and in-hospital mortality as the secondary outcome, we assessed the predictive value of VR 4 hours before extubation using a multivariate logistic regression model. Results: Of 3,569 ventilated patients who were included, the rate of extubation-failure was 12.7% and the median Sequential Organ Failure Assessment (SOFA) score was 6 before extubation. Increased VR, elevated heart rate, greater positive end-expiratory pressure, higher blood urea nitrogen level, higher platelet count, greater SOFA score, decreased pH, decreased tidal volume, presence of chronic pulmonary disease, paraplegia, and metastatic solid tumor were independent predictors for extubation failure. A threshold of 1.595 of VR was associated with prolonged intensive care unit length of stay, higher risk of mortality and extubation failure. The area under the receiver operating characteristic curve (ROC) for VR was 0.669 [0.635-0.703], which was significantly larger than the rapid shallow breathing index [0.510 (0.476-0.545)] and the partial pressure of oxygen to the fraction of inspired oxygen [0.586 (0.551-0.621)]. Conclusion: VR 4 hours before extubation was associated with extubation failure, mortality, and prolonged length of stay in the intensive care unit. VR provides good predictive performance for extubation failure (measured by ROC) than the rapid shallow breathing index. Further prospective studies are warranted to confirm these findings.

Acute and long-term effects of acetazolamide in presumed high loop gain sleep apnea.

BACKGROUND: The acute effect during positive pressure titration and long term efficacy of acetazolamide (AZT) in high loop gain sleep apnea (HLGSA) is inadequately assessed. We predicted that AZT may improve HLGSA in both conditions. METHODS: A retrospective analysis of polysomnograms from patients with presumed HLGSA and residual respiratory instability administered AZT (125 or 250 mg) about 3 h into an initially drug-free positive pressure titration. A responder was defined as ≥ 50% reduction of the apnea hypopnea index(AHI 3% or arousal) before and after AZT. A multivariable logistic regression model estimated responder predictors. Long term efficacy of AZT was assessed by comparing both auto-machine (aREIFLOW) and manually scored respiratory events (sREIFLOW) extracted from the ventilator, prior to and after 3 months of AZT, in a subset. RESULTS: Of the 231 participants (median age of 61[51-68] years) and 184 (80%) males in the acute effect testing: 77 and 154 patients were given 125 mg and 250 mg AZT. Compared to PAP alone, PAP plus AZT was associated with a lower breathing related arousal index (8 [3-16] vs. 5 [2-10], p < 0.001), and AHI3% (19 [7-37] vs. 11 [5-21], p < 0.001); 98 patients were responders. The non-rapid eye movement sleep (NREM) AHI3% (OR 1.031, 95%CI [1.016-1.046], p < 0.001) was a strong predictor for responder status with AZT exposure. In the 109 participants with 3-month data, both aREIFLOW and sREIFLOWwere significantly reduced after AZT. CONCLUSIONS: AZT acutely and chronically reduced residual sleep apnea in presumed HLGSA; NREM AHI3% is a response predictor. AZT was well tolerated and beneficial for at least 3 months.

Predictors and consequences of residual apnea during positive airway pressure therapy.

STUDY OBJECTIVES: Determine the risk factors for, and consequences of, residual apnea during long-term positive airway pressure (PAP) therapy for obstructive sleep apnea (OSA). METHODS: A prospective cohort study of 195 subjects after a split-night polysomnogram. Estimation of residual respiratory events on PAP were done by both automated and manual scoring of data in EncoreAnywhere™. Clinical and polysomnographic predictors of residual apnea were estimated. RESULTS: There were 166 and 101 patients still on PAP at the 3 and 12 months, respectively. Seventy four (44.6%) and 46 (45.5%) had a residual scored respiratory event index-flow (sREIFLOW) ≥ 15/hour of use and 46 (45.5%) at the 3rd and 12th month, respectively. Treatment phase central apnea hypopnea index (TCAHI), a surrogate of high loop gain, was the main predictor for residual sREIFLOW (ß = 0.345, p: 0.025) at the 3rd and 12th month (ß = 0.147, p: 0.020). TCAHI also predicted unstable breathing (U) %. The body mass index (hazard ratio [HR] 1.034, 95% CI 1.008-1.062, p: 0.012) and effective sREIFLOW>15/hour in the first month (HR 2.477, 95% CI 1.510-4.065, p < 0.001) were the key predictors for drop out of PAP use at the 12th month. Effective sREIFLOW>15/hour in the first month was also a predictor for median usage duration >4 h for 70% of the night at both the 3rd month (odds ratio [OR] 0.947, 95% CI 0.909-0.986, p: 0.008) and 12th month (OR 0.973, 95% CI 0.951-0.994, p: 0.014). CONCLUSIONS: Treatment-phase CAHI predicts long-term residual apnea on PAP. High residual disease adversely impacts adherence.

Association between ventilatory ratio and ICU mortality in interstitial lung disease patients on mechanical ventilation: A retrospective study.

BACKGROUND: Ventilatory ratio (VR) is a simple bedside index of ventilatory efficiency. Interstitial lung disease (ILD) is a diverse group of diseases that causes fibrosis or inflammation of the pulmonary parenchyma, and the main clinical manifestation is hypoxemia. To date, no study has explored ventilation efficiency in patients with ILD. OBJECTIVES: This study aimed to explore the features of VR in mechanically ventilated patients with ILD and their relationship with intensive care unit (ICU) mortality. METHODS: In this retrospective analysis, we included mechanically ventilated patients with ILD in the ICU of West China Hospital, Sichuan University, from 2013 to 2021. Demographic data and mechanical ventilation (MV) parameters within 24 h of intubation were collected. The characteristics of VR and their relationships with ICU mortality were also analyzed. RESULTS: 224 patients were included in the final analysis. There were 146 males (53.9%), and the median age was 65 years (interquartile range [IQR]54∼74). The mean value of VR was 2.22, and VR was significantly higher in nonsurvivors than in survivors (1.79 vs 2.32, P < 0.001). A high VR value was an independent risk factor for ICU mortality (odds ratio=1.602, P = 0.038) after adjustment. A high value of VR was associated with a shorter survival time after admission to ICU (hazard ratio=1.485, P = 0.006) CONCLUSIONS: VR in patients with ILD on MV was increased, and the VR of nonsurvivors within 24 h of intubation was higher than that of survivors. The high VR value within 24 h of intubation was an independent risk factor for ICU mortality after adjusting for other factors.

A longitudinal study of the accuracy of positive airway pressure therapy machine-detected apnea-hypopnea events.

STUDY OBJECTIVES: During positive airway pressure (PAP) therapy for sleep apnea syndromes, the machine-detected respiratory event index (REIFLOW) is an important method for clinicians to evaluate the beneficial effects of PAP. There are concerns about the accuracy of this detection, which also confounds a related question, How common and severe are residual events on PAP? METHODS: Patients with obstructive sleep apnea who underwent a split-night polysomnography were recruited prospectively. Those treated with PAP and tracked by the EncoreAnywhere system (Philips Respironics, Murrysville, PA) were analyzed. Those who stopped PAP within 1 month were excluded from this analysis. Compliance, therapy data, and waveform data were analyzed. Machine-detected vs manually scored events were compared at the first, third, sixth, and 12th month from PAP initiation. Logistic regression was used to determine factors associated with a high REIFLOW difference. RESULTS: One hundred and seventy-nine patients with a mean age 59.06 ± 13.97 years, median body mass index of 33.60 (29.75-38.75) kg/m2, and median baseline apnea-hypopnea index of 46.30 (31.50-65.90) events/h were included. The difference between the machine-detected REIFLOW and manually scored REIFLOW was 10.72 ± 8.43 events/h in the first month and remained stable for up to 12 months. Male sex and large leak ≥ 1.5% were more frequent in patients who had an REIFLOW difference of ≥ 5 events/h of use. A titration arousal index ≥ 15 events/h of sleep, and higher ratio of unstable to stable breathing were also associated with an REIFLOW difference ≥ 5 events/h of use. CONCLUSIONS: There is a substantial and sustained difference between manual and automated event estimates during PAP therapy, and some associated factors were identified. CITATION: Ni Y-N, Thomas RJ. A longitudinal study of the accuracy of positive airway pressure therapy machine-detected apnea-hypopnea events. J Clin Sleep Med. 2022;18(4):1121-1134.

Cardiopulmonary Sleep Spectrograms Open a Novel Window Into Sleep Biology-Implications for Health and Disease.

The interactions of heart rate variability and respiratory rate and tidal volume fluctuations provide key information about normal and abnormal sleep. A set of metrics can be computed by analysis of coupling and coherence of these signals, cardiopulmonary coupling (CPC). There are several forms of CPC, which may provide information about normal sleep physiology, and pathological sleep states ranging from insomnia to sleep apnea and hypertension. As CPC may be computed from reduced or limited signals such as the electrocardiogram or photoplethysmogram (PPG) vs. full polysomnography, wide application including in wearable and non-contact devices is possible. When computed from PPG, which may be acquired from oximetry alone, an automated apnea hypopnea index derived from CPC-oximetry can be calculated. Sleep profiling using CPC demonstrates the impact of stable and unstable sleep on insomnia (exaggerated variability), hypertension (unstable sleep as risk factor), improved glucose handling (associated with stable sleep), drug effects (benzodiazepines increase sleep stability), sleep apnea phenotypes (obstructive vs. central sleep apnea), sleep fragmentations due to psychiatric disorders (increased unstable sleep in depression).

The Effect of Conservative Oxygen Therapy in Reducing Mortality in Critical Care Patients: A Meta-Analysis and Trial Sequential Analysis.

Background: Conservative oxygen therapy can prevent both hypoxemia and hyperoxemia, but the effect on the prognosis of patients admitted to the intensive care unit (ICU) remains controversial. Methods: All controlled studies comparing conservative oxygen therapy and conventional oxygen therapy in adult patients admitted to the ICU were searched. The primary outcome was mortality, and the secondary outcomes were length of ICU stay (ICU LOS), length of hospital stay (hospital LOS), length of mechanical ventilation (MV) hours, new organ failure during ICU stay, and new infections during ICU stay. Results: Nine trials with a total of 5,759 patients were pooled in our final studies. Compared with conventional oxygen therapy, conservative oxygen therapy did not reduce overall mortality (Z = 0.31, p = 0.75) or ICU LOS (Z = 0.17, p = 0.86), with firm evidence from trial sequential analysis, or hospital LOS (Z = 1.98, p = 0.05) or new infections during the ICU stay (Z = 1.45, p = 0.15). However, conservative oxygen therapy was associated with a shorter MV time (Z = 5.05, p < 0.00001), reduction of new organ failure during the ICU stay (Z = 2.15, p = 0.03) and lower risk of renal replacement therapy (RRT) (Z = 2.18, p = 0.03). Conclusion: Conservative oxygen therapy did not reduce mortality but did decrease MV time, new organ failure and risk of RRT in critically ill patients. Systematic Review Registration: identifier [CRD42020171055].

Comparison of Actual Performance in the Flow and Fraction of Inspired O2 among Different High-Flow Nasal Cannula Devices: A Bench Study.

Background: High-flow nasal cannula (HFNC) oxygen therapy has been recommended for use in coronavirus disease 2019 (COVID-19) patients with acute respiratory failure and many other clinical conditions. HFNC devices produced by different manufacturers may have varied performance. Whether there is a difference in these devices and the extent of the differences in performance remain unknown. Methods: Four HFNC devices (AIRVO 2, TNI softFlow 50, HUMID-BH, and OH-70C) and a ventilator with an HFNC module (bellavista 1000) were evaluated. The flow was set at 20, 25, 30, 35, 40, 45, 50, 60, 70, and 80 L/min, and the FiO2 was set at 21%, 26%, 30%, 35%, 40%, 45%, 50%, 60%, 70%, 80%, and 90%. Then, one side of the cannulas was clipped to simulate the compression, bending, or blocking of the nasal cannulas. The flow and FiO2 of the delivered gas were recorded and compared among settings and devices. Results: The actual-flow and actual-FiO2 delivered by different settings and devices varied. AIRVO 2 had superior performance in flow and FiO2 accuracy. bellavista 1000 and OH-70C had good performance in the accuracy of actual-flows and actual-FiO2, respectively. bellavista 1000 and HUMID-BH had a larger flow range from 10 to 80 L/min, but only bellavista 1000 could provide a stable flow with an excessive resistance up to 60 L/min. TNI softFlow 50 had the best flow compensation and could provide sufficient flow with excessive resistance at 20-50 L/min. Conclusions: The variation in flow, FiO2 settings, and devices could influence the actual-flow and actual-FiO2 delivered. AIRVO 2 and OH-70C showed better FiO2 accuracy. TNI softFlow 50, bellavista 1000, and HUMID-BH could lower the risk of insufficient flow support due to accidental compression or blocking of the cannulas. In addition, ventilators with HFNC modules provided comparable flow and FiO2 and could be an alternative to standalone HFNC devices.

The role of acetazolamide in sleep apnea at sea level: a systematic review and meta-analysis.

STUDY OBJECTIVES: The recognition of specific endotypes as drivers of sleep apnea suggests the need of therapies targeting individual mechanisms. Acetazolamide is known to stabilize respiration at high altitude but benefits at sea level are less well understood. METHODS: All controlled studies of acetazolamide in obstructive sleep apnea and/or central sleep apnea (CSA) were evaluated. The primary outcome was the apnea-hypopnea index. RESULTS: Fifteen trials with a total of 256 patients were pooled in our systematic review. Acetazolamide reduced the overall apnea-hypopnea index (mean difference [MD] -15.82, 95% CI: -21.91 to -9.74, P < .00001) in central sleep apnea (MD -22.60, 95% CI: -29.11 to -16.09, P < .00001), but not in obstructive sleep apnea (MD -10.29, 95% CI: -33.34 to 12.77, P = .38). Acetazolamide reduced the respiratory related arousal index (MD -0.82, 95% CI: -1.56 to -0.08, P = .03), improved partial arterial of oxygen (MD 11.62, 95% CI: 9.13-14.11, P < .00001), mean oxygen saturation (MD 1.78, 95% CI: 0.53-3.04, P = .005), total sleep time (MD 25.74, 95% CI: 4.10-47.38, P = .02), N2 sleep (MD 3.34, 95% CI: 0.12-6.56, P = .04) and sleep efficiency (MD 4.83, 95% CI: 0.53-9.13, P = .03). CONCLUSIONS: Acetazolamide improves the apnea-hypopnea index and several sleep metrics in central sleep apnea. The drug may be of clinical benefit in patients with high loop gain apnea of various etiologies and patterns. The existence of high heterogeneity is an important limitation in applicability of our analysis. SYSTEMATIC REVIEW REGISTRATION: Registry: PROSPERO; Name: The effect of acetazolamide in patients with sleep apnea at sea level: a systematic review and meta analysis; URL: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020163316; Identifier: CRD42020163316.

Automated Apnea-Hypopnea Index from Oximetry and Spectral Analysis of Cardiopulmonary Coupling.

Rationale: The increased prevalence of obstructive sleep apnea (OSA) coincides with a severe shortage of sleep physicians. There is a need for widescale home-sleep-testing devices with accurate automated scoring to accelerate access to treatment.Objectives: To examine the accuracy of an automated apnea-index (AHI) derived from spectral analysis of cardiopulmonary coupling (CPC) extracted from electrocardiograms, combined with oximetry signals, in relation to polysomnograms (PSGs).Methods: Electrocardiograms and pulse-oximeter tracings on PSGs from APPLES (Apnea Positive Pressure Long-term Efficacy Study) were analyzed. Distinct CPC spectral bands were combined with the oxygen desaturation index to create a derived AHI (DAHI). Correlation statistics between the DAHI and the conventionally scored AHI, in which hypopneas required ≥50% airflow reduction alone or a lesser airflow reduction associated with ≥3% desaturation or arousal, using PSGs from APPLES were calculated.Results: A total of 833 adult subjects were included. The DAHI has excellent and strong correlation with the conventionally scored AHI on PSGs, with Pearson coefficients of 0.972 and receiver operating characteristic curves demonstrating strong agreement in all OSA categories: 98.5% in mild OSA (95% confidence interval [CI], 97.6-99.3%), 96.4% in moderate OSA (95% CI, 95.3-97.5%), and 98.5% in severe OSA (95% CI, 97.8-99.2%).Conclusions: An accurate automated AHI can be derived from oximetry and CPC.

The independent factors associated with oxygen therapy in COVID-19 patients under 65 years old.

BACKGROUND: The number of hospitalized young coronavirus disease 2019 (COVID-19) patients has increased significantly. However, specific data about COVID-19 patients under 65 years old who are admitted to the hospital are scarce. METHODS: The COVID-19 patients under 65 years old who were admitted to the hospital in Sichuan Province, Renmin Hospital of Wuhan University, and Wuhan Red Cross Hospital were included in this study. Demographic information, laboratory data and clinical treatment courses were extracted from electronic medical records. Risk factors associated with oxygen therapy were explored. RESULTS: Eight hundred thirty-three COVID-19 patients under 65 years old were included. Of the included patients, 29.4% had one or more comorbidities. Oxygen therapy was required in 63.1% of these patients, and the mortality was 2.9% among the oxygen therapy patients. Fever (odds ratio [OR] 2.072, 95% confidence interval [CI] 1.312-3.271, p = 0.002), dyspnea (OR 2.522, 95% CI 1.213-5.243, p = 0.013), chest distress (OR 2.278, 95% CI 1.160-4.473, p = 0.017), elevated respiratory rate (OR 1.114, 95% CI 1.010-1.228, p = 0.031), and decreased albumin (OR 0.932, 95% CI 0.880-0.987, p = 0.016) and globulin levels (OR 0.929, 95% 0.881-0.980, p = 0.007) were independent factors related to oxygen therapy. CONCLUSIONS: Oxygen therapy is highly required in COVID-19 patients under 65 years old who are admitted to the hospital, but the success rate is high. Respiratory failure-related symptoms, elevated respiratory rate, low albumin and globulin levels, and fever at admission are independent risk factors related to the requirement of oxygen.

High-Flow Nasal Cannula vs Conventional Oxygen Therapy for Postcardiothoracic Surgery.

BACKGROUND: High-flow nasal cannula (HFNC) oxygen therapy is widely used in extubated patients. We aim to evaluate the effect of HFNC compared with conventional oxygen therapy in adults after cardiothoracic surgery. METHODS: We conducted a literature search in PubMed, Embase, and ClinicalTrials for randomized controlled trials that compared HFNC with conventional oxygen therapy in extubated patients after cardiothoracic surgery. RESULTS: Eight studies with 1,086 subjects were included. Compared with conventional oxygen therapy, HFNC was associated with a significant reduction in the need for escalation of respiratory support (risk ratio 0.40, 95% CI 0.26-0.61, P < .001), re-intubation rate (risk ratio 0.35, 95% CI 0.13-0.96, P = .04), and length of hospital stay (mean difference -0.48, 95% CI -0.95 to -0.01, P = .05). No significant differences were found for the length of ICU stay (mean difference -0.09, 95% CI -0.21 to -0.04, P = .18), pulmonary complications (risk ratio 0.85, 95% CI 0.48-1.48, P = .56), or mortality rate (risk ratio 0.54, 95% CI 0.12-2.53, P = .44). CONCLUSIONS: HFNC may significantly reduce the need for the escalation of respiratory support and re-intubation rate, and might reduce the hospital stay. More high-quality randomized controlled trials are needed to further validate our results.

Correction to: The effect of corticosteroids on the mortality of patients with influenza pneumonia: a systematic review and meta-analysis.

An amendment to this paper has been published and can be accessed via the original article.

Could the loss of diaphragm thickness measured by computer tomography predict the rate of reintubation?

BACKGROUND: Diaphragm function loss is very common in the intensive care unit (ICU) and can predict the success of weaning. However, whether diaphragm thickness loss during mechanical ventilation (MV) as measured by computed tomography (CT) can predict the rate of reintubation remains unclear. Therefore, we hypothesized that a loss of diaphragm thickness would impact the outcome of weaning. METHODS: A retrospective study was performed on patients who received MV in the ICU of West China Hospital, Sichuan University. The diaphragm thickness of each patient on the CT scans within 48 hours after MV and 24 hours before weaning were measured by at least two independent investigators. The primary outcome was the rate of reintubation, and the second outcomes included hospital mortality and the length of ICU stay (ICU LOS) after extubation. RESULTS: A total of 145 patients were included in the analysis. According to the receiver operating characteristic curve, all patients were divided into two groups (less or more than 1.55 mm diaphragm thickness loss in reintubation). As a result, less loss of diaphragm thickness was a protective factor for the rate of reintubation [33% vs. 12%; adjusted odds ratio (aOR) 0.001; 95% confidence interval (CI), 0.001-0.271; P=0.018] and hospital mortality (18% vs. 4%; aOR 0.001; 95% CI, 0.001-0.035; P=0.007). However, no significant difference was found in the ICU LOS after extubation between the two groups. CONCLUSIONS: Less diaphragm thickness loss was related to a lower rate of reintubation and hospital mortality.

Use of High-Flow Nasal Cannula for Immunocompromise and Acute Respiratory Failure: A Systematic Review and Meta-Analysis.

BACKGROUND: Acute respiratory failure (ARF) is a common cause of emergency department (ED) and intensive care unit (ICU) admissions. High-flow nasal cannula oxygen therapy (HFNC) is widely used for patients with ARF. OBJECTIVE: Our aim was to evaluate the latest evidence regarding the application of HFNC in immunocompromised patients with ARF. METHODS: We searched PubMed, Embase, and Cochrane databases from inception to January 2019. The primary outcome was short-term mortality and the secondary outcomes were intubation rate and length of ICU stay. RESULTS: Eight studies involving 2,179 immunocompromised subjects with ARF were included. No significant differences for short-term mortality were observed when comparing HFNC with conventional oxygen therapy (COT) (risk ratio [RR] 0.89; 95% confidence interval [CI] 0.73 to 1.09; p = 0.25, I2 = 47%) and with noninvasive ventilation (NIV) (RR 0.66; 95% CI 0.37 to 1.18; p = 0.16, I2 = 58%). Lower intubation rates were found when comparing HFNC with COT (RR 0.89; 95% CI 0.80 to 0.99; p = 0.03, I2 = 0%) and no significant difference was found between HFNC and NIV (RR 0.74; 95% CI 0.46 to 1.19; p = 0.22, I2 = 67%). The length of ICU stay was similar when comparing HFNC with COT (mean difference [MD] 0.59; 95% CI -1.68 to 2.85; p = 0.61, I2 = 56%), but was significantly shorter when HFNC was compared with NIV (MD -2.13; 95% CI -3.98 to -0.29; p = 0.02, I2 = 0%). CONCLUSIONS: There was no significant difference in short-term mortality with use of HFNC when compared with COT or NIV for immunocompromised patients with ARF. A lower intubation rate than COT and a shorter length of ICU stay than NIV were observed in the HFNC group.

Direct oral anticoagulants for thromboprophylaxis in ambulatory patients with cancer.

Background: Venous thromboembolism (VTE) is a common complication in cancer patients. We aim to evaluate the effect and safety of direct oral anticoagulants (DOACs) as primary prophylaxis in ambulatory cancer patients.Methods: We conducted a literature search in PubMed, EMBASE and ClinicalTrials for studies that evaluated DOACs for thromboprophylaxis in cancer patients. RevMan 5.3 software was used for this meta-analysis.Results: Three randomized controlled trials (RCTs) with a total of 1465 patients were pooled in the meta-analysis. DOACs significantly reduced the symptomatic VTE incidence during intervention period (RR 0.23, CI 0.11-0.47, P<0.0001, I2=9%). Significantly lower total VTE incidence (RR 0.53, CI 0.36-0.78, P = 0.001, I2 =30%) and PE incidence (RR 0.50, CI 0.28-0.89, P = 0.02, I2 =5%) were found during the observation period, and a trend for less symptomatic DVT events was found in the DOACs group (RR 0.62, CI 0.37-1.04, P = 0.07, I2 =5%). No differences for all-cause mortality were found between groups (RR 0.92, CI 0.74-1.15, P = 0.47, I2 =14%). DOACs did not significantly increase major bleeding risks (RR 1.66, CI 0.72-3.83, P = 0.24, I2 =0%) during the intervention period or clinically relevant non-major bleeding events (RR 1.50, CI 0.90-2.49, P = 0.12, I2 =0%) and total bleeding events during the observation period (RR 1.50, CI 0.98-2.29, P = 0.06, I2 =0%).Conclusion: DOACs are effective for thromboprophylaxis in ambulatory cancer patients, but there is a potential risk of bleeding. DOACs may be recommended in selected patients at high risk of VTE. More high-quality studies are needed to further validate our results.Abbreviations: CAT: cancer-associated thrombosis; CI: confidence interval; DOAC: direct oral anticoagulant; DVT: deep vein thrombosis; LMWH: low molecular weight heparin; NNH: number needed to harm; NNT: number needed to treat; PE: pulmonary embolism; RCT: randomized controlled trials; RR: risk ratio; RD: rate difference; VTE: venous thromboembolism.