Noninvasive ventilation for acute respiratory failure

Noninvasive ventilation refers to any form of ventilatory support applied without the use of an endotracheal tube. It offers the potential to provide primary treatment for acute respiratory failure while avoiding complications associated with mechanical ventilation with endotracheal intubation. Noninvasive ventilation has been most commonly studied in hypercapnic respiratory failure. A review of randomized, controlled studies shows mixed results and methodologic limitations affect the interpretation of current evidence. Patient selection is clearly the most important issue in considering noninvasive ventilation for acute respiratory failure. Unfortunately, patients who benefit from noninvasive ventilation represent only a minority of the total group with any one disease, and thus it is difficult to make broad conclusions concerning applicability of this treatment modality. Future studies are needed to focus on determining the specific patient populations who will benefit the most, evaluating the optimal ventilatory mode and mask for providing noninvasive ventilation, and clarifying its impact on clinical outcomes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Noninvasive ventilation for acute respiratory failure

PURPOSE OF REVIEW: This review critically examines recent literature related to applications of noninvasive ventilation in the acute setting. RECENT FINDINGS: Recent articles have strengthened the evidence supporting the use of noninvasive ventilation for patients with cardiogenic pulmonary edema and exacerbation of severe chronic pulmonary obstructive disease. In the former, however, it remains unclear whether noninvasive ventilation offers any significant advantages over continuous positive airway pressure. The rate of myocardial infarction seems to be no higher when patients with cardiogenic pulmonary edema are treated with noninvasive ventilation rather than continuous positive airway pressure, although caution is still advised in patients with acute coronary syndromes. Noninvasive ventilation also does not seem to increase the risk of dissemination of severe acute respiratory syndrome to health care workers as long as strict isolation procedures are used. Noninvasive ventilation facilitates weaning in patients with chronic obstructive pulmonary disease but should not be used routinely to treat extubation failure, and necessary intubation should not be delayed. Guidelines for the use of noninvasive ventilation can alter caregivers' behavior but have not been clearly shown to improve outcomes. Outcomes do seem to improve, however, as caregivers acquire experience with the technique. SUMMARY: The recent literature has refined some of the current indications for noninvasive ventilation in the acute-care setting, including chronic pulmonary obstructive disease and cardiogenic pulmonary edema. Guidelines for use are now being developed, and outcomes seem to be improving, partly as a consequence of greater caregiver experience and possibly related to technologic advances.     

Noninvasive ventilation in patients with hypoxemic acute respiratory failure

PURPOSE OF REVIEW: To discuss the recent literature concerning the use of noninvasive ventilation for hypoxemic acute respiratory failure. RECENT FINDINGS: The benefits of noninvasive ventilation for patients with hypoxemic acute respiratory failure are unclear. In immunocompromised patients and following thoracic surgery, there is a strong rationale for using noninvasive ventilation to treat acute respiratory failure. Prophylactic continuous positive airway pressure after abdominal or thoracic surgery and prophylactic noninvasive ventilation in patients at risk of extubation failure have proved beneficial. Recent studies show that noninvasive ventilation has a favourable impact in immunocompetent patients with acute lung injury/acute respiratory distress syndrome, but caution is required. In hypoxemic acute respiratory failure after extubation, one study reported excess mortality in patients treated with noninvasive ventilation, possibly related to the delay for intubation. A major issue is avoiding undue noninvasive ventilation prolongation and staying alert for predictors of early noninvasive ventilation failure. Caution, close monitoring, and broad experience are required. SUMMARY: Hypoxemic acute respiratory failure may benefit from noninvasive ventilation or continuous positive airway pressure, but undue prolongation should be avoided. In postextubation respiratory failure there is no evidence for routine use of noninvasive ventilation.     

无创机械通气在重症肺炎合并急性呼吸衰竭中的应用

目的探讨无创机械通气（NIV）在救治重症肺炎合并急性呼吸衰竭中的价值。方法收集24例重症肺炎合并急性呼吸衰竭患者进行NIV的临床资料,回顾性分析NIV前后缺氧的改善情况、并发症及转归等。结果24例患者使用了机械通气,14例仅采用NIV,气体交换获得持久性改善,避免了气管插管,并最终存活出院。另10例先采用NIV,后改用有创机械通气。所有患者均能较好耐受。NIV使用1h后,PaO2和平均氧合指数较治疗前有明显提高（P〈0．05）。结论NIV可用于重症肺炎合并急性呼吸衰竭的早期呼吸支持治疗,能有效改善缺氧,耐受性和安全性好。     

Noninvasive and invasive ventilation in acute respiratory failure associated with bronchiectasis

Purpose  

To describe the outcomes of patients with bronchiectasis and acute respiratory failure (ARF) treated with noninvasive ventilation (NIV) and invasive mechanical ventilation (IMV) after a failure of conservative measures, and to identify the predictors of hospital mortality and NIV failure.     

Noninvasive pressure support versus proportional assist ventilation in acute respiratory failure

Background Although conventional pressure ventilation (PSV) decreases the rate of intubation in acute respiratory failure, patient-ventilator dyssynchrony is a frequent cause of failure. In proportional assist ventilation (PAV), pressure is applied by the ventilator in proportion to the patient-generated volume and flow; therefore, there is automatic synchrony between the patient's effort and the ventilatory cycle.Objective The aim of this study was to compare the effects of PSV and PAV during noninvasive ventilation in the treatment of acute respiratory failure.Design Prospective randomised study.Setting A multidisciplinary 24-bed intensive care unit of an acute-care teaching hospital in Alicante, Spain.Patients This study included 117 consecutive adult patients with acute respiratory failure randomised to noninvasive ventilation delivered by PSV (n = 59) or PAV (n = 58).Measurements and results There were no statistically significant differences between patients assigned to each mode of ventilation with regard to baseline parameters and aetiological diagnoses of acute respiratory failure. With regard to outcome data, no significant differences were observed between PSV and PAV in the frequency of intubation (37% vs 34%), mortality rate (29% vs 28%), and mean length of stay. Subjective comfort (0–10 visual analogue scale) was rated higher and intolerance occurred less frequently (3.4% vs 15%, P = 0.03) in the PAV than in the PSV mode.Conclusions Although PAV seems more comfortable and intolerance occurred less frequently, no major differences exist in terms of physiological improvement or in terms of outcomes when comparing PSV and PAV.An editorial regarding this article can be found in the same issue ()     

Noninvasive ventilation for acute hypoxemic respiratory failure in patients with COVID-19

AimNoninvasive ventilation (NIV) is known to reduce intubation in patients with acute hypoxemic respiratory failure (AHRF). We aimed to assess the outcomes of NIV application in COVID-19 patients with AHRF.Materials & methodsIn this retrospective cohort study, patients with confirmed diagnosis of COVID-19 and AHRF receiving NIV in general wards were recruited from two university-affiliated hospitals. Demographic, clinical, and laboratory data were recorded at admission. The failure of NIV was defined as intubation or death during the hospital stay.ResultsBetween April 8 and June 10, 2020, 61 patients were enrolled into the final cohort. NIV was successful in 44 out of 61 patients (72.1%), 17 patients who failed NIV therapy were intubated, and among them 15 died. Overall mortality rate was 24.6%. Patients who failed NIV were older, and had higher respiratory rate, PaCO₂, D-dimer levels before NIV and higher minute ventilation and ventilatory ratio on the 1-st day of NIV. No healthcare workers were infected with SARS-CoV-2 during the study period.ConclusionsNIV is feasible in patients with COVID-19 and AHRF outside the intensive care unit, and it can be considered as a valuable option for the management of AHRF in these patients.     

PK：急性呼吸衰竭患者适用无创正压机械通气吗？——正方：当用则用，物尽其用

学术辩论对于辨明学术发展进程中某些有争议的问题，是非常重要的一种学术交流形式。在中华医学会重症医学分会全国重症医学学术会议上，专家们就急性呼吸衰竭患者是否适用于无创机械通气进行了辩论，本刊以CCCM论坛的形式将其发表，希望能引起大家热烈的讨论。[编者按]     

Noninvasive proportional assist ventilation compared with noninvasive pressure support ventilation in hypercapnic acute respiratory failure

OBJECTIVES: To compare short-term administration of noninvasive proportional assist ventilation (NIV-PAV) and pressure support ventilation (NIV-PSV). DESIGN: Prospective, crossover, randomized study. SETTING: Medicosurgical intensive care unit in a nonteaching hospital. PATIENTS: Twelve chronic obstructive pulmonary disease patients admitted for hypercapnic acute respiratory failure. INTERVENTION: NIV-PSV and NIV-PAV given in a randomized order after baseline evaluation in continuous positive airway pressure. Using a flow-triggering ventilator, NIV-PAV was adjusted using the runaway method and compared with NIV-PSV at similar peak inspiratory airway pressure. MEASUREMENTS AND MAIN RESULTS: Flow, airway pressure, and changes in esophageal pressure were measured and the tidal volume, the patient's inspiratory work of breathing, and the esophageal pressure--time product were calculated. Arterial pH and PaCO(2) were measured and breathing comfort was assessed using a visual analogic scale. Peak inspiratory airway pressure (17 +/- 3 cm H(2)O) and tidal volume were similarly increased with the two modalities with no change in respiratory rate. The change in esophageal pressure was similarly decreased (from 20 +/- 8 cm H(2)O in continuous positive airway pressure to 12 +/- 7 in NIV-PSV and 10 +/- 5 cm H(2)O in NIV-PAV) as well as inspiratory muscle effort indexes. Arterial pH and PaCO(2) were similarly improved. Breathing comfort was significantly improved in NIV-PAV (+38 +/- 38%) but not in NIV-PSV (+11 +/- 23%). The tidal volume was more variable in NIV-PAV (89 +/- 18%) than in NIV-PSV (15 +/- 8%) and changes in tidal volume variability were significantly correlated (p =.02) with changes in breathing comfort. CONCLUSIONS: In chronic obstructive pulmonary disease patients with hypercapnic acute respiratory failure, NIV-PAV was able to unload inspiratory muscles similarly to NIV-PSV but may be more comfortable than NIV-PSV.     

Noninvasive ventilation in acute respiratory failure--a meta-analysis update

OBJECTIVE: To present a meta-analytic update on the effects of noninvasive ventilation (NIV) in the management of acute respiratory failure. DESIGN: Meta-analysis of randomized controlled clinical trials in acute respiratory failure comparing NIV with standard medical therapy. PATIENTS: Randomized controlled trials of NIV in acute respiratory failure were identified by search of i) MEDLINE (1966-2000), ii) published abstracts from scientific meetings, and iii) bibliographies of relevant articles. MEASUREMENTS AND MAIN RESULTS: Of the 15 randomized controlled trials that were identified (13 published and 2 in abstract form), 8 studies were on exacerbations of chronic obstructive pulmonary disease (COPD) and 7 on diverse disease processes in both COPD and non-COPD groups ("mixed-group"). Because of underlying heterogeneity of treatment effects, only the DerSimonian-Laird random effects estimator was used and reported. The effects of NIV vs. standard therapy on mortality and subsequent invasive mechanical ventilation (MV) was assessed as risk difference, and hospital length of stay as mean weighted difference (days). NIV was associated with reduction in mortality (8%, p = .03), reduced need for MV (19%, p = .001) and shortened hospital length of stay (2.74 days, p = .004). In the COPD cohort, significant reductions in mortality (13%, p = .001), need for MV (18%, p = .02), and hospital length of stay (5.66 days, p = .01) were observed in the group treated with NIV. In contrast, in the mixed-group, there was no demonstrable reduction in mortality (0%, p = .98). However, there was significant reduction in the need for MV (22%, p = .001). Publication bias was not evident on analysis. Treatment effect i) as mortality or need for mechanical ventilation was not modified by enrollment pH, PaCO2, nor age and ii) was not related (as log odds ratio) to underlying risk (control arm log odds). Cumulative meta-analysis did not demonstrate any substantial variation in the point estimates with the addition of the recently published studies. However a contraction in the confidence intervals was observed in the COPD subgroup. Complication rates were not significantly different in the standard medical therapy group and the NIV treated patients. CONCLUSION: Substantial reductions in mortality and the need for subsequent MV were associated with NIV in acute respiratory failure, especially in the COPD subgroup. Hospital length of stay was variably affected. Heterogeneity of treatment effects was observed.     

Noninvasive ventilation in respiratory failure due to cystic fibrosis

BACKGROUND: Noninvasive positive-pressure ventilation (NIPPV) is increasingly used as an effective means of avoiding endotracheal intubation and mechanical ventilation in patients with respiratory insufficiency or failure. METHODS: We retrospectively reviewed our experience with NIPPV to treat respiratory failure in five patients with cystic fibrosis (CF). RESULTS: Despite chronic lung disease related to CF, none of our cases were end-stage. All patients had recent pulmonary function tests showing a forced expiratory volume in 1 second (FEV1) of more than 30% predicted for age. All patients had progressive atelectasis, hypoxemia, and impending respiratory failure related to an acute pulmonary exacerbation or upper abdominal surgical procedure (open gastrostomy tube placement). Respiratory rates decreased, oxygen saturation increased, fraction of inspired oxygen (FiO2) requirement decreased, transcutaneous CO2 decreased, and atelectasis resolved with NIPPV. CONCLUSIONS: Use of NIPPV provides effective respiratory support while avoiding the need for endotracheal intubation. The applications of NIPPV, reports of its use in patients with CF, and the equipment required are reviewed.     

Noninvasive ventilation for acute respiratory failure after lung resection: an observational study

Background  A single prospective randomized study found that, in selected patients with acute respiratory failure (ARF) following lung resection, noninvasive ventilation (NIV) decreases the need for endotracheal mechanical ventilation and improves clinical outcome. Method  We prospectively evaluated early NIV use for ARF after lung resection during a 4-year period in the setting of a medical and a surgical ICU of a university hospital. We documented demographics, initial clinical characteristics and clinical outcomes. NIV failure was defined as the need for tracheal intubation. Results  Among 690 patients at risk of severe complications following lung resection, 113 (16.3%) experienced ARF, which was initially supported by NIV in 89 (78.7%), including 59 with hypoxemic ARF (66.3%) and 30 with hypercapnic ARF (33.7%). The overall success rate of NIV was 85.3% (76/89). In-ICU mortality was 6.7% (6/89). The mortality rate following NIV failure was 46.1%. Predictive factors of NIV failure in univariate analysis were age (P = 0.046), previous cardiac comorbidities (P = 0.0075), postoperative pneumonia (P = 0.0016), admission in the surgical ICU (P = 0.034), no initial response to NIV (P < 0.0001) and occurrence of noninfectious complications (P = 0.037). Only two independent factors were significantly associated with NIV failure in multivariate analysis: cardiac comorbidities (odds ratio, 11.5; 95% confidence interval, 1.9–68.3; P = 0.007) and no initial response to NIV (odds ratio, 117.6; 95% confidence interval, 10.6–1305.8; P = 0.0001). Conclusion  This prospective survey confirms the feasibility and efficacy of NIV in ARF following lung resection. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. This work was presented during the September 2008 ESICM congress in Lisbon international meeting and published as an abstract.     

Noninvasive positive pressure ventilation as treatment for acute respiratory failure in critically ill patients

Our current state of knowledge on noninvasive positive pressure ventilation (NPPV) and technical aspects are discussed in the present review. In patients with chronic obstructive pulmonary disease, NPPV can be considered a valid therapeutic option to prevent endotracheal intubation. Evidence suggests that, before eventual endotracheal intubation, NPPV should be considered as first-line intervention in the early phases of acute exacerbation of chronic obstructive pulmonary disease. Small randomized and non-randomized studies on the application of NPPV in patients with acute hypoxaemic respiratory failure showed promising results, with reduction in complications such as sinusitis and ventilator-associated pneumonia, and in the duration of intensive care unit stay. The conventional use of NPPV in hypoxaemic acute respiratory failure still remains controversial, however. Large randomized studies are still needed before extensive clinical application in this condition.     

Noninvasive positive pressure ventilation reverses acute respiratory failure in select "do-not-intubate" patients

OBJECTIVE: To determine the outcome from the use of noninvasive positive pressure ventilation (NPPV) in "do-not-intubate" (DNI) patients in acute respiratory failure. DESIGN: Prospective observational study. SETTING: University-affiliated large medical center. PATIENTS: All patients with DNI status who received NPPV for a 1-yr period. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Demographic, physiologic, and laboratory data were collected before initiation, 2 hrs after initiation, and each morning and evening for as long as NPPV was provided. Data were recorded on 137 episodes of acute respiratory failure in 131 DNI patients. Hospital mortality rate was 37.5% in 24 patients with an exacerbation of chronic obstructive pulmonary disease (COPD), 39% in 28 patients with acute cardiogenic pulmonary edema, 68% in nine patients with non-COPD hypercapnic ventilatory failure, 77% in 13 post-extubation respiratory failure patients, and 86% in 57 patients with hypoxemic respiratory failure. Advanced cancer was present in 40 patients and was associated with increased risk of death (85% mortality rate, p = .002). A score based on the Simplified Acute Physiology Score (SAPS) II and serum albumin level calculated before NPPV was predictive of hospital outcome. CONCLUSIONS: NPPV is successful in reversing acute respiratory failure and preventing hospital mortality in DNI patients with COPD and cardiogenic pulmonary edema but not in patients with post-extubation failure, hypoxemic respiratory failure, or end-stage cancer. An easy-to-calculate score combining SAPS II and serum albumin level is a good prediction of outcome in DNI patients receiving NPPV.     

Noninvasive ventilation for treating acute respiratory failure in AIDS patients with Pneumocystis carinii pneumonia

OBJECTIVE: To compare noninvasive positive pressure ventilation (NPPV) vs. invasive mechanical ventilation in AIDS patients with Pneumocystis carinii pneumonia (PCP)-related acute respiratory failure (ARF). DESIGN: A single-center, prospective, case-control trial. SETTING: An ICU of a private tertiary hospital specialized in infectious disease. PATIENTS: Forty-eight AIDS patients with severe PCP-related ARF needing mechanical ventilation.Interventions: Twenty-four patients treated with NPPV by a facial mask strictly matched with 24 patients treated with invasive ventilation by endotracheal intubation. RESULTS: Use of NPPV avoided intubation in 67% of patients, and avoidance of intubation was associated with improved survival (100% vs. 38%; P=0.003). NPPV-treated patients required fewer invasive devices ( P<0.001) and had a lower incidence of pneumothoraces (8.3% vs. 37.5%; P=0.039). The NPPV-treated group required a nurse workload similar to that of the conventional ventilation group, but this group had a shorter duration of stay in the ICU ( P=0.013). The NPPV-treated group had a lower mortality in the ICU, the hospital and within 2 months of study entry. Differences in mortality between the two groups disappeared after 6 months. CONCLUSIONS: The findings of this study seem to provide further support for applying NPPV in AIDS patients with severe PCP-related ARF as a first-line therapeutic choice, but randomized controlled trials are required to confirm our results.