Sequential use of noninvasive pressure support ventilation for acute exacerbations of COPD

Quality Improvement Initiative to Improve Initiation and Acceptability of Noninvasive Ventilation in Critically Ill Children

OBJECTIVES

To evaluate if the use of a quality improvement (QI) initiative improves initiation and acceptability of noninvasive ventilation (NIV) in critically ill children with respiratory distress.

METHODS

The study was carried out in 3 phases over a period of 6 mo in the pediatric intensive care unit of a tertiary care hospital in children aged 2 mo to 14 y of age. In phase 1, data were collected for 1 mo and reasons for NIV failure were identified. In phase 2, process changes like adherence to checklist, monitoring, and one-day orientation program were instituted. The plan-do-study-act (PDSA) cycle was carried out in each phase. In phase 3, which was for 2 mo, the acceptance of NIV was measured and results were compared with phase 1.

RESULTS

A total of 37 patients were included, 12 in phase 1 and 25 in phase 3. NIV failure was recorded in 5 (42%) and 2 (8%) patients in phase 1 and phase 3 (p = 0.025), respectively. The cause of NIV failure was intolerance to the interface in both phases. Sedation was used in 18 (72%) patients in phase 3, as compared to 2 patients in phase 1.

CONCLUSIONS

The use of a quality improvement initiative in the form of a protocol, checklist, and training of the treating team resulted in improved tolerance to NIV, and thereby, its success. Use of sedation may help improve tolerance to the interface and contribute to its success.

Prospective Comparative Evaluation of Noninvasive and Invasive Mechanical Ventilation in Patients of Chronic Obstructive Pulmonary Disease with Acute Respiratory Failure Type II

Introduction:

Acute respiratory failure is a potential complication of chronic obstructive pulmonary disease (COPD) that severely affects the health of the patient and may require mechanical ventilation. We compared noninvasive and invasive mechanical ventilation in COPD patients with acute respiratory failure type II to validate clinical outcome based on biochemical analysis of arterial blood gases (ABGs) and pulmonary parameters in terms of duration of mechanical ventilation, period spent in intensive care unit (ICU) and mortality.

Materials and Methods:

After approval of institutional ethical committee 100 patients were selected for randomized prospective controlled trial and divided into two groups of 50 each according to mode of mechanical ventilation. Group-I patients managed with noninvasive ventilation (NIV) Group-ll managed with invasive ventilation.

Results:

Demographic data between two groups were comparable. ABG parameters were better at 2 h and 6 h interval in NIV as compared to invasive ventilation (P < 0.05). The duration of ventilation and total time spent in ICU was 106±10 hours and 168±8 hours respectively in NIV group and 218 ± 12 and 280 ± 20 in invasive group. On intergroup comparison these were significantly less in noninvasive group (P < 0.05). Hospital acquired pneumonia occurred in 10% of patients in invasive group whereas no incidence of pneumonia found in noninvasive group. Mortality rate was 12% in invasive groups and 2% in noninvasive groups.

Conclusion:

NIV leads to significant improvement in ABG and pulmonary parameters and it reduces duration of ventilation and total period of hospital stay so it can be used as an alternative to invasive ventilation as first-line treatment in COPD.

The effect of helium-oxygen-assisted mechanical ventilation on chronic obstructive pulmonary disease exacerbation: A systemic review and meta-analysis

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is often accompanied by acute exacerbations. Patients of COPD exacerbation suffering from respiratory failure often need the support of mechanical ventilation. Helium-oxygen can be used to reduce airway resistance during mechanical ventilation. The aim of this study is to evaluate the effect of helium-oxygen-assisted mechanical ventilation on COPD exacerbation through a meta-analysis.

METHODS

A comprehensive literature search through databases of Pub Med (1966∼2016), Ovid MEDLINE (1965∼2016), Cochrane EBM (1991∼2016), EMBASE (1974∼2016) and Ovid MEDLINE was performed to identify associated studies. Randomized clinical trials met our inclusion criteria that focus on helium-oxygen-assisted mechanical ventilation on COPD exacerbation were included. The quality of the papers was evaluated after inclusion and information was extracted for meta-analysis.

RESULTS

Six articles and 392 patients were included in total. Meta-analysis revealed that helium-oxygen-assisted mechanical ventilation reduced Borg dyspnea scale and increased arterial PH compared with air-oxygen. No statistically significant difference was observed between helium-oxygen and air-oxygen as regards to WOB, PaCO2 , OI, tracheal intubation rates and mortality within hospital.

CONCLUSIONS

Our study suggests helium-oxygen-assisted mechanical ventilation can help to reduce Borg dyspnea scale. In terms of the tiny change of PH, its clinical benefit is negligible. There is no conclusive evidence indicating the beneficial effect of helium-oxygen-assisted mechanical ventilation on clinical outcomes or prognosis of COPD exacerbation.

Intermittent noninvasive ventilation after extubation in patients with chronic respiratory disorders: a multicenter randomized controlled trial (VHYPER)

PURPOSE

Early noninvasive ventilation (NIV) after extubation decreases the risk of respiratory failure and lowers 90-day mortality in patients with hypercapnia. Patients with chronic respiratory disease are at risk of extubation failure. Therefore, it could be useful to determine the role of NIV with a discontinuous approach, not limited to patients with hypercapnia. We assessed the efficacy of early NIV in decreasing respiratory failure after extubation in patients with chronic respiratory disorders.

METHODS

A prospective randomized controlled multicenter study was conducted. We enrolled 144 mechanically ventilated patients with chronic respiratory disorders who tolerated a spontaneous breathing trial. Patients were randomly allocated after extubation to receive either NIV (NIV group, n = 72), performed with a discontinuous approach, for the first 48 h, or conventional oxygen treatment (usual care group, n = 72). The primary endpoint was decreased respiratory failure within 48 h after extubation. Analysis was by intention to treat. This trial was registered with ClinicalTrials.gov (NCT01047852).

RESULTS

Respiratory failure after extubation was less frequent in the NIV group: 6 (8.5%) versus 20 (27.8%); p = 0.0016. Six patients (8.5%) in the NIV group versus 13 (18.1%) in the usual care group were reintubated; p = 0.09. Intensive care unit (ICU) mortality and 90-day mortality did not differ significantly between the two groups (p = 0.28 and p = 0.33, respectively). Median postrandomization ICU length of stay was lower in the usual care group: 3 days (IQR 2-6) versus 4 days (IQR 2-7; p = 0.008). Patients with hypercapnia during a spontaneous breathing trial were at risk of developing postextubation respiratory failure [adjusted odds ratio (95% CI) = 4.56 (1.59-14.00); p = 0.006] and being intubated [adjusted odds ratio (95% CI) = 3.60 (1.07-13.31); p = 0.04].

CONCLUSIONS

Early NIV performed following a sequential protocol for the first 48 h after extubation decreased the risk of respiratory failure in patients with chronic respiratory disorders. Reintubation and mortality did not differ between NIV and conventional oxygen therapy.

Use of the Draeger Apollo to Deliver Bilevel Positive Pressure Ventilation During Awake Frontal Craniotomy for a Patient with Severe Chronic Obstructive Pulmonary Disease

In this case report, we describe the use of the Draeger Apollo anesthesia machine to deliver bilevel positive airway pressure (BiPAP) to a patient with severe chronic obstructive pulmonary disease and a history of lung resection undergoing frontal craniotomy for the removal of a brain tumor under moderate to deep sedation. BiPAP in the perioperative period has been described for purposes of preoxygenation and postextubation recruitment. Although its utility as a mode of ventilation during moderate to deep sedation has been demonstrated, it has not come into widespread use. We describe the intraoperative use of pressure support mode on the anesthesia machine to deliver noninvasive positive pressure ventilation through a standard anesthesia mask. Given its ease of access and effectiveness, it is our belief that intraoperative BiPAP may reduce hypoxemia and/or hypercarbia in patients with chronic obstructive pulmonary disease and obstructive sleep apnea undergoing moderate to deep sedation.

Timing of noninvasive ventilation failure: causes, risk factors, and potential remedies

Background

Identifying the predictors of noninvasive ventilation (NIV) failure has attracted significant interest because of the strong link between failure and poor outcomes. However, very little attention has been paid to the timing of the failure. This narrative review focuses on the causes of NIV failure and risk factors and potential remedies for NIV failure, based on the timing factor.

Results

The possible causes of immediate failure (within minutes to <1 h) are a weak cough reflex, excessive secretions, hypercapnic encephalopathy, intolerance, agitation, and patient-ventilator asynchrony. The major potential interventions include chest physiotherapeutic techniques, early fiberoptic bronchoscopy, changing ventilator settings, and judicious sedation. The risk factors for early failure (within 1 to 48 h) may differ for hypercapnic and hypoxemic respiratory failure. However, most cases of early failure are due to poor arterial blood gas (ABGs) and an inability to promptly correct them, increased severity of illness, and the persistence of a high respiratory rate. Despite a satisfactory initial response, late failure (48 h after NIV) can occur and may be related to sleep disturbance.

Conclusions

Every clinician dealing with NIV should be aware of these risk factors and the predicted parameters of NIV failure that may change during the application of NIV. Close monitoring is required to detect early and late signs of deterioration, thereby preventing unavoidable delays in intubation.

Sleep in hypercapnic critical care patients under noninvasive ventilation: conventional versus dedicated ventilators

OBJECTIVE

To compare sleep quality between two types of ventilators commonly used for noninvasive ventilation: conventional ICU ventilators and dedicated noninvasive ventilators; and to evaluate sleep during and between noninvasive ventilation sessions in critically ill patients.

DESIGN

Physiological sleep study with a randomized assessment of the ventilator type.

SETTING

Medical ICU in a university hospital.

PATIENTS

Twenty-four patients admitted for acute hypercapnic respiratory failure requiring noninvasive ventilation.

INTERVENTIONS

Patients were randomly assigned to receive noninvasive ventilation with either an ICU ventilators (n = 12) or a dedicated noninvasive ventilators (n = 12), and their sleep and respiratory parameters were recorded by polysomnography from 4 PM to 9 AM on the second, third, or fourth day after noninvasive ventilation initiation.

MEASUREMENTS AND MAIN RESULTS

Sleep architecture was similar between ventilator groups, including sleep fragmentation (number of arousals and awakenings/hr), but the dedicated noninvasive ventilators group showed a higher patient-ventilator asynchrony-related fragmentation (28% [17-44] vs. 14% [7.0-22]; p = 0.02), whereas the ICU ventilators group exhibited a higher noise-related fragmentation. Ineffective efforts were more frequent in the dedicated noninvasive ventilators group than in the ICU ventilators group (34 ineffective efforts/hr of sleep [15-125] vs. two [0-13]; p < 0.01), possibly as a result of a higher tidal volume (7.2 mL/kg [6.7-8.8] vs. 5.8 [5.1-6.8]; p = 0.04). More sleep time occurred and sleep quality was better during noninvasive ventilation sessions than during spontaneous breathing periods (p < 0.05) as a result of greater slow wave and rapid eye movement sleep and lower fragmentation.

CONCLUSIONS

There were no observed differences in sleep quality corresponding to the type of ventilator used despite slight differences in patient-ventilator asynchrony. Noninvasive ventilation sessions did not prevent patients from sleeping; on the contrary, they seem to aid sleep when compared with unassisted breathing.

Oxygen therapy for pneumonia in adults

BACKGROUND

Oxygen therapy is widely used in the treatment of lung diseases. However, the effectiveness of oxygen therapy as a treatment for pneumonia is not well known.

OBJECTIVES

To determine the effectiveness and safety of oxygen therapy in the treatment of pneumonia in adults older than 18 years.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) 2011, Issue 4, part of The Cochrane Library, www.thecochranelibrary.com (accessed 9 December 2011), which includes the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (1948 to November week 3, 2011) and EMBASE (1974 to December 2011).

SELECTION CRITERIA

Randomised controlled trials (RCTs) of oxygen therapy for adults with community-acquired pneumonia (CAP) and nosocomial (hospital-acquired) pneumonia (HAP or NP) in intensive care units (ICU).

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed abstracts and assessed data for methodological quality.

MAIN RESULTS

Three RCTs met our inclusion criteria. The studies enrolled 151 participants with CAP or immunosuppressed patients with pulmonary infiltrates. Overall, we found that non-invasive ventilation can reduce the risk of death in the ICU, odd ratio (OR) 0.28, 95% confidence interval (CI) 0.09 to 0.88; endotracheal intubation, OR 0.26, 95% CI 0.11 to 0.61; complications, OR 0.23, 95% CI 0.08 to 0.70; and shorten ICU length of stay, mean duration (MD) -3.28, 95% CI -5.41 to -1.61.Non-invasive ventilation and standard oxygen supplementation via a Venturi mask were similar when measuring mortality in hospital, OR 0.54, 95% CI 0.11 to 2.68; two-month survival, OR 1.67, 95% CI 0.53 to 5.28; duration of hospital stay, MD -1.00, 95% CI -2.05 to 0.05; and duration of mechanical ventilation, standard MD -0.26, 95% CI -0.66 to 0.14. Some outcomes and complications of non-invasive ventilation were varied according to different participant populations. We also found that some subgroups had a high level of heterogeneity when conducting pooled analyses.

AUTHORS' CONCLUSIONS

Non-invasive ventilation can reduce the risk of death in the ICU, endotracheal intubation, shorten ICU stay and length of intubation. Some outcomes and complications of non-invasive ventilation were varied according to different participant populations. Other than the oxygen therapy, we must mention the importance of standard treatment by physicians. The evidence is weak and we did not include participants with pulmonary tuberculosis and cystic fibrosis. More RCTs are required to answer these clinical questions. However, the review indicates that non-invasive ventilation may be more beneficial than standard oxygen supplementation via a Venturi mask for pneumonia.

Comparison of noninvasive ventilation by sequential use of mask and helmet versus mask in acute exacerbation of chronic obstructive pulmonary disease: a preliminary study

BACKGROUND

Noninvasive positive pressure ventilation (NPPV) using a face mask is the ventilatory mode of choice in selected patients experiencing acute exacerbation of chronic obstructive pulmonary disease (COPD). A high incidence of intolerance limits the use of this approach.

OBJECTIVE

To evaluate the sequential use of mask and helmet during NPPV in patients with severe exacerbation of COPD in order to reduce the intolerance to these devices.

METHODS

Fifty-three patients ventilated for the first 2 h with NPPV by mask were studied. If gas exchange and clinical status improved, they were randomized to continue on NPPV by mask or helmet. Physiological parameters were measured at admission, after the first 2 h on NPPV by mask, 4 h after randomization and at discharge. Need for intubation, ventilatory assistance, length of stay (LOS) and complications were recorded.

RESULTS

After the first 2 h of NPPV, gas exchange and clinical parameters improved in 40 patients. Four hours after randomization, PaCO(2) was lower in the mask group than in the helmet group. Nine patients in the mask group and 2 in the helmet group failed NPPV, 8 and 1, respectively, owing to intolerance. Time of noninvasive ventilation and LOS were lower in the mask than in the helmet group.

CONCLUSIONS

In patients with acute exacerbation of COPD and undergoing NPPV, the sequential use of a mask and helmet diminished the incidence of failure. Under the present experimental conditions, the use of a helmet increased LOS and the duration of artificial ventilation.

A multicenter, randomized trial of noninvasive ventilation with helium-oxygen mixture in exacerbations of chronic obstructive lung disease

OBJECTIVE

To assess the effect of a helium-oxygen mixture on intubation rate and clinical outcomes during noninvasive ventilation in acute exacerbation of chronic obstructive pulmonary disease.

DESIGN

Multicenter, prospective, randomized, controlled trial.

SETTING

Seven intensive care units.

PATIENTS

A total of 204 patients with known or suspected chronic obstructive pulmonary disease and acute dyspnea, Paco2> 45 mm Hg and two among the following factors: pH <7.35, Paco2 <50 mm Hg, respiratory rate >25/min.

INTERVENTIONS

Noninvasive ventilation randomly applied with or without helium (inspired oxygen fraction 0.35) via a face mask.

MEASUREMENTS AND MAIN RESULTS

Duration and complications of NIV and mechanical ventilation, endotracheal intubation, discharge from intensive care unit and hospital, mortality at day 28, adverse and serious adverse events were recorded. Follow-up lasted until 28 days since enrollment. Intubation rate did not significantly differ between groups (24.5% vs. 30.4% with or without helium, p = .35). No difference was observed in terms of improvement of arterial blood gases, dyspnea, and respiratory rate between groups. Duration of noninvasive ventilation, length of stay, 28-day mortality, complications and adverse events were similar, although serious adverse events tended to be lower with helium (10.8% vs. 19.6%, p = .08).

CONCLUSIONS

Despite small trends favoring helium, this study did not show a statistical superiority of using helium during NIV to decrease the intubation rate in acute exacerbation of chronic obstructive pulmonary disease.

[Field 5. Safety practices procedures for mechanical ventilation. French-speaking Society of Intensive Care. French Society of Anesthesia and Resuscitation]

Invasive or endotracheal mechanical ventilation can lead to numerous complications likely to burden morbidity and mortality of patients in the intensive care unit. Various safety practices for mechanical ventilation may involve intubation, the mechanical ventilation period, weaning and extubation, the use of tracheostomy as well as non-invasive ventilation. The main objective of safety practices described in this chapter is to prevent or avoid the main risks due to invasive mechanical ventilation.

A case of attempted suicide from the ingestion of formalin

The ingestion of formalin causes disorders in the oral cavity, the gastrointestinal tract, liver, kidney, lung, heart, and central nervous system in the early phase of reaction. The stomach suffers the most severe damage in such cases because the formalin is in contact with the gastric mucosa longer than in the other parts of the gastrointestinal tract. Gastric ulcers and mild hemorrhaging are frequently seen. There are no reported cases of gastric perforations in Japan (n= 15), and there are only two reported cases in other countries since 1950 (n = 11). The ingestion of formalin could lead to peritonitis without perforation because of gastric wall inflammation. Cicatrical stricture of the stomach tends to be a major problem in the late phase of formalin ingestion. Similar to our case, seven of twelve reported cases of cicatrical deformity survived without operation. Therefore, a gastrectomy for the cicatrical deformity might not be always indicated if the patients are able to feed themselves sufficiently or if parenteral nutrition can be provided.

Automatic adjustment of noninvasive pressure support with a bilevel home ventilator in patients with acute respiratory failure: a feasibility study

OBJECTIVE

To test the feasibility of applying noninvasive ventilation (NIV) using a prototype algorithm implemented in a bilevel ventilation device designed to adjust pressure support (PS) to maintain a clinician-set alveolar ventilation in patients with acute respiratory failure after initial stabilization.

DESIGN AND SETTING

Prospective crossover interventional study in an intensive care unit, university hospital.

PATIENTS

19 patients receiving NIV for acute hypercapnic respiratory failure (13 men, 6 women; mean age 70+/-11 years).

METHODS

The same bilevel ventilator was used with manually adjusted PS and with the automated algorithm (autoPS), set to maintain the same alveolar ventilation as in PS. Sequence (measurements at end of each period): (a) prior to initiating NIV (baseline 1); (b) 45 min with manually set PS; (c) 60 min without NIV; (d) 45 min with autoPS; (e) 60 min without NIV; (f) 45 min with manually set PS.

RESULTS

The magnitude of decrease in PaCO(2) and increase in pH with autoPS was comparable to that of conventional PS, with the same alveolar ventilation and level of PS. No technical problem occurred in autoPS mode, and no NIV trial had to be discontinued because of patient discomfort.

CONCLUSIONS

These results suggest that the alveolar ventilation based automatic control of PS during NIV with a bilevel device is feasible and leads to beneficial effects in patients with acute respiratory failure comparable to those of manually set PS. Further studies should now explore the potential of this system over longer periods in patients with acute and chronic respiratory failure.

Intrapulmonary percussive ventilation improves the outcome of patients with acute exacerbation of chronic obstructive pulmonary disease using a helmet

OBJECTIVE

To evaluate the effect of intrapulmonary percussive ventilation (IPV) by mouthpiece during noninvasive positive-pressure ventilation with helmet in patients with exacerbation of chronic obstructive pulmonary disease (COPD).

DESIGN

Randomized clinical trial.

SETTING

General intensive care unit, university hospital.

PATIENTS

Forty patients with exacerbation of COPD ventilated with noninvasive positive-pressure ventilation by helmet were randomized to two different mucus clearance strategies: IPV (IPV group) vs. respiratory physiotherapy (Phys group). As historical control group, 40 patients receiving noninvasive positive pressure and ventilated by face mask treated with respiratory physiotherapy were studied.

INTERVENTIONS

Two daily sessions of IPV (IPV group) or conventional respiratory physiotherapy (Phys group).

MEASUREMENTS AND MAIN RESULTS

Physiologic variables were measured at entry in the intensive care unit, before and after the first session of IPV, and at discharge from the intensive care unit. Outcome variables (need for intubation, ventilatory assistance, length of intensive care unit stay, and complications) were also measured. All physiologic variables improved after IPV. At discharge from the intensive care unit, Paco2 was lower in the IPV group compared with the Phys and control groups (mean +/- sd, 58 +/- 5.4 vs. 64 +/- 5.2 mm Hg, 67.4 +/- 4.2 mm Hg, p < .01). Pao2/Fio2 was higher in IPV (274 +/- 15) than the other groups (Phys, 218 +/- 34; control, 237 +/- 20; p < .01). In the IPV group, time of noninvasive ventilation (hrs) (median, 25th-75th percentile: 61, 60-71) and length of stay in the intensive care unit (days) (7, 6-8) were lower than other groups (Phys, 89, 82-96; control, 87, 75-91; p < .01; and Phys, 9, 8-9; control, 10, 9-11; p < .01).

CONCLUSIONS

IPV treatment was feasible for all patients. Noninvasive positive-pressure ventilation by helmet associated with IPV reduces the duration of ventilatory treatment and intensive care unit stay and improves gas exchange at discharge from intensive care unit in patients with severe exacerbation of COPD.

Automatic adjustment of pressure support by a computer-driven knowledge-based system during noninvasive ventilation: a feasibility study

OBJECTIVE

To evaluate the feasibility of using a knowledge-based system designed to automatically titrate pressure support (PS) to maintain the patient in a "respiratory comfort zone" during noninvasive ventilation (NIV) in patients with acute respiratory failure.

DESIGN AND SETTING

Prospective crossover interventional study in an intensive care unit of a university hospital.

PATIENTS

Twenty patients.

INTERVENTIONS

After initial NIV setting and startup in conventional PS by the chest physiotherapist NIV was continued for 45 min with the automated PS activated.

MEASUREMENTS AND RESULTS

During automated PS minute-volume was maintained constant while respiratory rate decreased significantly from its pre-NIV value (20+/-3 vs. 25+/-3 bpm). There was a trend towards a progressive lowering of dyspnea. In hypercapnic patients PaCO(2) decreased significantly from 61+/-9 to 51+/-2 mmHg, and pH increased significantly from 7.31+/-0.05 to 7.35+/-0.03. Automated PS was well tolerated. Two system malfunctions occurred prompting physiotherapist intervention.

CONCLUSIONS

The results of this feasibility study suggest that the system can be used during NIV in patients with acute respiratory failure. Further studies should now determine whether it can improve patient-ventilator interaction and reduce caregiver workload.

Comparison of tolerance of facemask vs. mouthpiece for non-invasive ventilation

This prospective, single centre, randomised, cross-over study compares patient tolerance of the facemask and mouthpiece for delivery of non-invasive ventilation in an intensive care unit. Twenty-seven patients with acute respiratory failure were scheduled for two 45-min sessions of non-invasive ventilation with facemask and mouthpiece. The order of the sessions was chosen at random. Nurses and patients assessed the tolerance of both techniques using a visual analogue scale. The time spent by nurses and the changes in respiratory parameters were recorded. The facemask was better tolerated than the mouthpiece; all the cases of non-invasive ventilation withdrawal (n = 5) occurred with mouthpieces (p = 0.026). Less nursing time was required using the facemask for the 22 patients who underwent both procedures (p = 0.01). However, the difference in tolerance scores was not significant. Non-invasive ventilation with both facemask and mouthpiece improved the P(a)o(2)/F(i)o(2) ratio, increased the pH and decreased the P(a)co(2). Only non-invasive ventilation with the facemask lowered the respiratory rate. The facemask appears to be a better initial choice for non-invasive ventilation when compared to mouthpiece, but both can be effective.

Noninvasive ventilation to prevent respiratory failure after extubation in high-risk patients

OBJECTIVE

Compared with standard medical therapy (SMT), noninvasive ventilation (NIV) does not reduce the need for reintubation in unselected patients who develop respiratory failure after extubation. The goal of this study was to assess whether early application of NIV, immediately after extubation, is effective in preventing postextubation respiratory failure in an at-risk population.

DESIGN

Multiple-center, randomized controlled study.

SETTING

Multiple hospitals.

PATIENTS

Ninety-seven consecutive patients with similar baseline characteristics, requiring >48 hrs of mechanical ventilation and considered at risk of developing postextubation respiratory failure (i.e., patients who had hypercapnia, congestive heart failure, ineffective cough and excessive tracheobronchial secretions, more than one failure of a weaning trial, more than one comorbid condition, and upper airway obstruction).

INTERVENTIONS

After a successful weaning trial, the patients were randomized to receive NIV for > or = 8 hrs a day in the first 48 hrs or SMT. Primary outcome was the need for reintubation according to standardized criteria. Secondary outcomes were intensive care unit and hospital mortality, as well as time spent in the intensive care unit and in hospital.

MEASUREMENTS AND MAIN RESULTS

Compared with the SMT group, the NIV group had a lower rate of reintubation (four of 48 vs. 12 of 49; p = .027). The need for reintubation was associated with a higher risk of mortality (p < .01). The use of NIV resulted in a reduction of risk of intensive care unit mortality (-10%, p < .01), mediated by the reduction for the need of reintubation.

CONCLUSIONS

NIV was more effective than SMT in preventing postextubation respiratory failure in a population considered at risk of developing this complication.

Acute applications of noninvasive positive pressure ventilation

Noninvasive positive-pressure ventilation (NPPV) has been used increasingly to treat acute respiratory failure (ARF). The best indications for its use are ARF in patients with COPD exacerbations, acute pulmonary edema, and immunocompromised states. For these indications, multiple controlled trials have demonstrated that therapy with NPPV avoids intubation and, in the case of COPD and immunocompromised patients, reduces mortality as well. NPPV is used to treat patients with numerous other forms of ARF, but the evidence is not as strong for its use in those cases, and patients must be selected carefully. The best candidates for NPPV are able to protect their airway, are cooperative, and are otherwise medically stable. Success is optimized when a skilled team applies a well-fitted, comfortable interface. Ventilator settings should be adjusted to reduce respiratory distress while avoiding excessive discomfort, patient-ventilator synchrony should be optimized, and adequate oxygenation should be assured. The appropriate application of NPPV in the acute care setting should lead to improved patient outcomes and more efficient resource utilization.

Chronic obstructive pulmonary disease * 9: management of ventilatory failure in COPD

The management of respiratory failure during acute exacerbations of COPD and during chronic stable COPD is reviewed and the role of non-invasive and invasive mechanical ventilation is discussed.

[Noninvasive positive pressure ventilation for acute respiratory failure in chronic obstructive pulmonary disease in a general respiratory ward]

BACKGROUND AND OBJECTIVE

In patients with acute exacerbations of chronic obstructive pulmonary disease (COPD), noninvasive ventilatory support (NPPV) with bilevel positive airway pressure (BiPAP) may improve clinical and physiological parameters. The present study used a randomized, prospective design to evaluate the possible benefits of NPPV plus standard therapy versus standard therapy alone in patients admitted with acute hypercapnic respiratory failure in a respiratory unit of a tertiary hospital.

PATIENTS AND METHOD

Forty-one patients were included in the study. Of them, 20 were randomly allocated to receive NPPV with a standard mask connected to a BiPAP ventilatory assist device (Respironics Inc, Murrysville, PA) and 21 to standard therapy. Both groups had similar characteristics upon their admission in the hospital.

RESULTS

The use of noninvasive ventilation significantly reduced the respiratory rates and improved the conscious level within the first 2 h (p < 0.001). There were significant differences in PaCO2 and pH (p < 0.05) at 6 h of treatment. The need for intubation was 5% in the NPPV group vs 14% in the control group. The length of hospital stay was significantly shorter in the NPPV group (7 vs 10 days; p < 0.01). Nasal NPPV was well tolerated and complications were uncommon and mild.

CONCLUSIONS

Early use of noninvasive ventilation in patients with acute exacerbation of chronic obstructive pulmonary disease leads to a more rapid improvement of physiological variables. Moreover, it is possible to apply this treatment in a general respiratory ward.

Positive pressure mechanical ventilation

There have been numerous advances in the application of positive pressure mechanical ventilation in the last two decades. As knowledge of pulmonary physiology expands, the application of modes and parameters to maximize the efficacy and minimize the complications of ventilatory support continues to advance. As the use of noninvasive ventilation becomes more widespread, its usefulness in certain clinical entities such as COPD exacerbations and acute cardiogenic pulmonary edema will become more prominent. The role of specific modes and parameters of these devices likely will be further refined to maximize outcomes.

Helium-oxygen versus air-oxygen noninvasive pressure support in decompensated chronic obstructive disease: A prospective, multicenter study

OBJECTIVE

To study whether noninvasive pressure support ventilation (NIPSV) with helium/oxygen (He/oxygen), which can reduce dyspnea, PaCO2, and work of breathing more than NIPSV with air/oxygen in decompensated chronic obstructive pulmonary disease, could have beneficial consequences on outcome and hospitalization costs.

DESIGN

Prospective, randomized, multicenter study.

SETTING

Intensive care units of three tertiary care university hospitals.

PATIENTS

All patients with chronic obstructive pulmonary disease admitted to the intensive care units for NIPSV during a 24-month period.

INTERVENTIONS

Patients were randomized to NIPSV with air/oxygen or He/oxygen. NIPSV settings, number of daily trials, decision to intubate, and intensive care unit and hospital discharge criteria followed standard practice guidelines.

RESULTS

A total of 123 patients (male/female ratio, 71:52; age, 71 +/- 10 yrs, Acute Physiology and Chronic Health Evaluation II, 17 +/- 4) were included. Intubation rate (air/oxygen 20% vs. He/oxygen 13%) and length of stay in the intensive care unit (air/oxygen 6.2 +/- 5.6 vs. He/oxygen 5.1 +/- 4 days) were comparable. The post-intensive care unit hospital stay was lower with He/oxygen (air/oxygen 19 +/- 12 vs. He/oxygen 13 +/- 6 days, p < .002). Cost of NIPSV gases was higher with He/oxygen, but total hospitalization costs were lower by $3,348 per patient with He/oxygen. No complications were associated with the use of He/oxygen.

CONCLUSION

He/oxygen did not significantly reduce intubation rate or intensive care unit stay, but hospital stay was shorter and total costs were lower. He/oxygen NIPSV can be safely administered and could prove to be a cost-effective strategy.

Noninvasive mechanical ventilation in clinical practice: a 2-year experience in a medical intensive care unit

OBJECTIVE

To evaluate the feasibility and outcome results of noninvasive mechanical ventilation (NIV) in daily clinical practice outside any prospective protocol-driven trial.

DESIGN

An observational retrospective cohort study.

SETTING

A 22-bed medical intensive care unit in a university hospital.

PATIENTS

A consecutive cohort of 124 patients who underwent 143 NIV trials, regardless of the indication, over two consecutive years (1997-1998).

INTERVENTIONS

None.

RESULTS

A total of 604 acute respiratory failure patients underwent mechanical ventilation, and 143 NIVs were performed in 124 patients. The overall prevalence of NIV use was 143 of 604 patients (24%) in three groups: hypoxemic acute respiratory failure (29.5%), hypercapnic acute respiratory failure (41%), and weaning/postextubation (29.5%). Intubation was avoided in 92 of 143 of the NIVs performed (64%), 19 (13%) after changing the initial NIV mode (i.e., a success rate of 62%, 51%, and 86% in the three groups, respectively). A total of 35 of 51 intubated patients (69%) required intubation during the first 24 hrs of NIV. Intensive care unit stay was 12 +/- 10 days for the overall population, and mortality, when NIV failed, was 13 of 124 patients (10.5%). Arterial pH (p =.0527) and the Pao2/Fio2 ratio (p =.0482) after 1 hr were the only independent predictive factors for NIV failure by multivariate analysis.

CONCLUSIONS

This study confirms the results of controlled trials and demonstrates the feasibility and efficacy of NIV applied in daily clinical practice. These results suggest that NIV should be considered as a first-line ventilatory treatment in various etiologies of acute respiratory failure and as a promising weaning technique and postextubation ventilatory support. However, NIV should certainly be performed by a motivated and sufficiently trained care team.

Noninvasive ventilation in acute exacerbations of chronic obstructive pulmonary disease in patients with and without home noninvasive ventilation

OBJECTIVE

The frequency of home ventilation has increased greatly. The objective of the study was, first, to compare the outcome of episodes of acute exacerbation of chronic obstructive pulmonary disease treated with mask intermittent positive-pressure ventilation (MIPPV) in patients with home MIPPV and in patients without home ventilatory support and, second, for each category of patients, to compare patients successfully ventilated with MIPPV with those who failed with MIPPV.

DESIGN

Prospective, controlled, nonrandomized clinical study.

SETTING

Medical intensive care unit of a university hospital.

PATIENTS

In the groups with and without home MIPPV, respectively, 31 and 78 episodes of acute exacerbations of chronic obstructive pulmonary disease were studied.

INTERVENTIONS

MIPPV was performed in a sequential mode and delivered through a full-face mask with a bilevel positive airway pressure system.

MEASUREMENTS AND MAIN RESULTS

The clinical and functional characteristics of the two groups, at admission, were similar. In groups with and without home ventilation, respectively, success rates were 68% and 72% (p =.68), length of intensive care unit stay was 8 +/- 6 and 10 +/- 4 days (p =.02), and intensive care unit deaths were 13% and 8% (p =.30). In survivors and in groups with and without home ventilation, respectively, the total time of ventilatory assistance in intensive care unit was 5 +/- 4 and 8 +/- 4 days (p =.004), and the length of intensive care unit stay was 7 +/- 5 and 10 +/- 4 days (p =.003). A greater correction of pH, after 45 mins of MIPPV with optimal settings, was recorded in the success patients than in the failure patients, respectively; in the group with home MIPPV, the pH after 45 mins was 7.34 +/- 0.04 vs. 7.31 +/- 0.04 (p =.06), and in the group without home MIPPV, pH was 7.34 +/- 0.04 vs. 7.30 +/- 0.04 (p =.001).

CONCLUSION

MIPPV may also be favorable during episodes of acute exacerbations in patients with chronic obstructive pulmonary disease. Experience with MIPPV could benefit selected patients in the management of acute respiratory failure.

Non-invasive ventilation in acute exacerbations of chronic obstructive pulmonary disease: long term survival and predictors of in-hospital outcome

BACKGROUND

Non-invasive ventilation (NIV) reduces the need for intubation and the mortality associated with an exacerbation of chronic obstructive pulmonary disease (COPD). This study aimed to identify factors that could be used to stratify patients according to their risk of requiring invasive mechanical ventilation. The second aim was to determine the long term survival of patients treated with and without NIV.

METHODS

In this prospective multicentre randomised controlled trial 118 patients were allocated to standard treatment and 118 to NIV between November 1996 and September 1998. Arterial blood gas tensions and respiratory rate were recorded at enrolment and after 1 and 4 hours. Prognostic factors were identified using logistic regression analysis. All patients were followed until death or 1 January 1999.

RESULTS

At enrolment the H+ concentration (OR 1.22 per nmol/l, 95% CI 1.09 to 1.37, p<0.01) and Paco2 (OR 1.14 per kPa, 95% CI 1.14 to 1.81, p<0.01) were associated with treatment failure. Allocation to NIV was protective (OR 0.39, 95% CI 0.19 to 0.80). After 4 hours of treatment improvement in acidosis (OR 0.89 per nmol/l, 95% CI 0.82 to 0.97, p<0.01) and fall in respiratory rate (OR 0.92 per breaths/min, 95% CI 0.84 to 0.99, p=0.04) were associated with success. Median length of survival was 16.8 months in those treated with NIV and 13.4 months in those receiving standard treatment (p=0.12). The trend in improved survival was attributable to prevention of death during the index admission.

CONCLUSION

Initial pH and hypercapnia can be used to stratify groups of patients according to their risk of needing intubation. NIV reduces this risk and progress should be monitored using change in respiratory rate and pH. The long term survival after NIV is sufficiently good to render treatment appropriate.

Non-invasive ventilation in acute exacerbations of chronic obstructive pulmonary disease: long term survival and predictors of in-hospital outcome

BACKGROUND

Non-invasive ventilation (NIV) reduces the need for intubation and the mortality associated with an exacerbation of chronic obstructive pulmonary disease (COPD). This study aimed to identify factors that could be used to stratify patients according to their risk of requiring invasive mechanical ventilation. The second aim was to determine the long term survival of patients treated with and without NIV.

METHODS

In this prospective multicentre randomised controlled trial 118 patients were allocated to standard treatment and 118 to NIV between November 1996 and September 1998. Arterial blood gas tensions and respiratory rate were recorded at enrolment and after 1 and 4 hours. Prognostic factors were identified using logistic regression analysis. All patients were followed until death or 1 January 1999.

RESULTS

At enrolment the H(+) concentration (OR 1.22 per nmol/l, 95% CI 1.09 to 1.37, p<0.01) and PaCO2 (OR 1.14 per kPa, 95% CI 1.14 to 1.81, p<0.01) were associated with treatment failure. Allocation to NIV was protective (OR 0.39, 95% CI 0.19 to 0.80). After 4 hours of treatment improvement in acidosis (OR 0.89 per nmol/l, 95% CI 0.82 to 0.97, p<0.01) and fall in respiratory rate (OR 0.92 per breaths/min, 95% CI 0.84 to 0.99, p=0.04) were associated with success. Median length of survival was 16.8 months in those treated with NIV and 13.4 months in those receiving standard treatment (p=0.12). The trend in improved survival was attributable to prevention of death during the index admission.

CONCLUSION

Initial pH and hypercapnia can be used to stratify groups of patients according to their risk of needing intubation. NIV reduces this risk and progress should be monitored using change in respiratory rate and pH. The long term survival after NIV is sufficiently good to render treatment appropriate.

Management of acute exacerbations of COPD: a summary and appraisal of published evidence

STUDY OBJECTIVES

To critically review the available data on the diagnostic evaluation, risk stratification, and therapeutic management of patients with acute exacerbations of COPD.

DESIGN, SETTING, AND PARTICIPANTS

English-language articles were identified from the following databases: MEDLINE (from 1966 to week 5, 2000), EMBASE (from 1974 to week 18, 2000), HealthStar (from 1975 to June 2000), and the Cochrane Controlled Trials Register (2000, issue 1). The best available evidence on each subtopic then was selected for analysis. Randomized trials, sometimes buttressed by cohort studies, were used to evaluate therapeutic interventions. Cohort studies were used to evaluate diagnostic tests and risk stratification. Study design and results were summarized in evidence tables. Individual studies were rated as to their internal validity, external validity, and quality of study design. Statistical analyses of combined data were not performed.

MEASUREMENT AND RESULTS

Limited data exist regarding the utility of most diagnostic tests. However, chest radiography and arterial blood gas sampling appear to be useful, while short-term spirometry measurements do not. In terms of the risk of relapse and the risk of death after hospitalization for an acute exacerbation, there are identifiable clinical variables that are associated with these outcomes. Therapies for which there is evidence of efficacy include bronchodilators, corticosteroids, and noninvasive positive-pressure ventilation. There is also support for the use of antibiotics in patients with more severe exacerbations. Based on limited data, mucolytics and chest physiotherapy do not appear to be of benefit, and oxygen supplementation appears to increase the risk of respiratory failure in an identifiable subgroup of patients.

CONCLUSIONS

Although suggestions for appropriate management can be made based on available evidence, the supporting literature is spotty. Further high-quality research is needed and will require an improved, generally acceptable, and transportable definition of the syndrome "acute exacerbation of COPD" and improved methods for observing and measuring outcomes.

Noninvasive ventilation in immunosuppressed patients with pulmonary infiltrates, fever, and acute respiratory failure

BACKGROUND

Avoiding intubation is a major goal in the management of respiratory failure, particularly in immunosuppressed patients. Nevertheless, there are only limited data on the efficacy of noninvasive ventilation in these high-risk patients.

METHODS

We conducted a prospective, randomized trial of intermittent noninvasive ventilation, as compared with standard treatment with supplemental oxygen and no ventilatory support, in 52 immunosuppressed patients with pulmonary infiltrates, fever, and an early stage of hypoxemic acute respiratory failure. Periods of noninvasive ventilation delivered through a face mask were alternated every three hours with periods of spontaneous breathing with supplemental oxygen. The ventilation periods lasted at least 45 minutes. Decisions to intubate were made according to standard, predetermined criteria.

RESULTS

The base-line characteristics of the two groups were similar; each group of 26 patients included 15 patients with hematologic cancer and neutropenia. Fewer patients in the noninvasive-ventilation group than in the standard-treatment group required endotracheal intubation (12 vs. 20, P=0.03), had serious complications (13 vs. 21, P=0.02), died in the intensive care unit (10 vs. 18, P=0.03), or died in the hospital (13 vs. 21, P=0.02).

CONCLUSIONS

In selected immunosuppressed patients with pneumonitis and acute respiratory failure, early initiation of noninvasive ventilation is associated with significant reductions in the rates of endotracheal intubation and serious complications and an improved likelihood of survival to hospital discharge.

Bronchoscopy with bronchoalveolar lavage via the laryngeal mask airway in high-risk hypoxemic immunosuppressed patients

OBJECTIVE

Fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) are major tools in the diagnosis of pulmonary complications in immunocompromised patients. Nevertheless, severe hypoxemia is an accepted contraindication to FOB in nonintubated patients. The purpose of this study was to evaluate the feasibility and safety of laryngeal mask airway (LMA)-supported FOB with BAL in immunosuppressed patients with suspected pneumonia and severe hypoxemia.

DESIGN

Prospective, clinical investigation.

SETTING

Medical intensive care unit of a university hospital.

PATIENTS

Forty-six immunosuppressed patients admitted to our intensive care unit with suspected pneumonia and Pao2/Fio2 < or = 125.

INTERVENTIONS

After the administration of 0.3 mg x kg(-1) of etomidate, the patients were ventilated manually while receiving 1.0 Fio2. After the administration of 2.5 mg x kg(-1) of propofol, followed by an infusion of 9.1 +/- 2.3 mg x kg(-1) x hr(-1) of propofol, the LMA (size 3 or 4) was placed and connected to a bag-valve unit to allow manual ventilation with 1.0 Fio2. The FOB was introduced through a T-adapter attached to the LMA, and BAL was carried out with 150 mL of sterile 0.9% saline solution by sequential instillation and aspiration of 50-mL aliquots.

MEASUREMENTS AND MAIN RESULTS

Three patients developed transient laryngospasm during passage of the bronchoscope via the LMA, which resolved with deepening of anesthesia. Changes in mean blood pressure, heart rate, Pao2/Fio2, and Paco2 values induced by the procedure did not reach significance. Seven patients (15%) presented hypotension (mean blood pressure, <60 mm Hg) maintained for 120 +/- 40 secs, which required plasma expanders in three cases. Oxygen desaturation to <90% occurred in six patients (13%) during BAL. Nevertheless, the lowest Sao2 during the procedure was significantly higher than the initial Sao2 (94% +/- 4% vs. 90% +/- 2%). No patient required tracheal intubation during the 8 hrs after the procedure. BAL had an overall diagnostic yield of 65%. Because of the results obtained by using the BAL analysis, treatment was modified in 33 (72%) cases.

CONCLUSION

Application of the LMA appears to be a safe and effective alternative to intubation for accomplishing FOB with BAL in immunosuppressed patients with suspected pneumonia and severe hypoxemia.

Noninvasive continuous positive airway pressure in neutropenic patients with acute respiratory failure requiring intensive care unit admission

OBJECTIVE

To evaluate the tolerance and the efficacy of noninvasive continuous positive airway pressure (CPAP) in severe acute respiratory failure occurring in intensive care unit (ICU) neutropenic patients with hematologic malignancies, and to establish predictive variables of efficacy of this method.

DESIGN

Prospective study over a 5-yr period.

SETTING

Hematologic and medical intensive care unit of a teaching hospital.

METHODS

Among 129 neutropenic patients admitted to the ICU, 64 patients presented with febrile acute hypoxemic normocapnic respiratory failure (PaO2/FIO2 ratio <200) and were enrolled. In addition to standard therapy, patients received CPAP with a facial mask. The initial settings of the CPAP were 6 cm H2O positive end-expiratory pressure and FIO2 0.8 (80%). Physiologic measurements were performed at the end of 45 mins of ventilation with first adjustments. CPAP was used with a sequential mode (45 mins/3 hrs). CPAP was efficient if intubation was avoided.

RESULTS

The setting of CPAP, after adjustments, was as follows: positive end-expiratory pressure 7 +/- 1 cm H2O and FIO2 0.7 +/- 0.1 (70% +/- 10%). For the 64 patients, CPAP was administered for a total of 6 +/- 2 hrs during the first 24 hrs. The mean duration of CPAP was 7 +/- 3 days. A reduction in respiratory rate to less than 25 breaths/min was achieved in 53% of patients. PaO2/FIO2 ratio increased from 128 +/- 32 to 218 +/- 28. CPAP was successful in avoiding endotracheal intubation in 16/64 patients. A total of 16 responders and four nonresponders survived. Hepatic failure was a criterion indicating the failure of CPAP: 1/16 vs. 26/48 (p = .001). In multivariate analysis, two variables were predictive of failure of CPAP: Simplified Acute Physiology Score II (58 +/- 14 vs. 41 +/- 11) and a hepatic failure at the entry into the study.

CONCLUSION

CPAP was efficient in 25% of cases. All the responders survived. This noninvasive method was used as a way to avoid mechanical ventilation, which is well correlated with a poor prognosis in neutropenic ICU patients. Further controlled studies are needed to confirm the efficacy of noninvasive CPAP and to evaluate the most appropriate selection of immunocompromised patients.

Short-term adverse effects in humans of ingested mineral oils, their additives and possible contaminants--a review

The toxicological databases for petroleum refinery products such as mineral oils, as well as for their potential contaminants and additives, were reviewed for human cases of poisoning by the oral route. The aim was to determine whether any overlooked adulterant in the oil implicated as the cause of the 1981 outbreak of Toxic Oil Syndrome (TOS) in Spain, may have been responsible for the unusual symptomatology characterizing this disease. The essential features of TOS were peripheral eosinophilia, pulmonary oedema and endothelial damage in the acute phase; myalgia, sensory neuropathy, hepatic injury, skin oedema and sicca in the intermediate phase; and peripheral neuropathy, muscle wasting, scleroderma and hepatopathy in the chronic phase. Of the more than 70 chemical entities and mixtures reviewed here, none had been reported as producing adverse toxic effects upon ingestion resembling the specific set of symptoms and progression that characterized TOS. Because of their viscosity, the most commonly recorded disease process associated with oral ingestion of petroleum refinery products was lipid pneumonia, implicating lung exposure via aspiration. The mineral oil additives and contaminants comprised a highly diverse range of chemical entities, producing a variety of symptoms in instances of poisoning. Specifically, no chemical entity amongst the refinery products, additives or contaminants was described as inducing a syndrome involving vasculitis accompanied by thrombotic events, along with immunological consequences (such as T-lymphocyte activation and cytokine release), as is considered to be the cellular basis of TOS.

Noninvasive ventilation as a systematic extubation and weaning technique in acute-on-chronic respiratory failure: a prospective, randomized controlled study

Prolonged duration of endotracheal mechanical ventilation (ETMV) is associated with an increased morbidity and mortality in intensive care unit (ICU) patients. The aim of this study was to assess the usefulness of noninvasive ventilation (NIV) as a systematic extubation and weaning technique to reduce the duration of ETMV in acute-on-chronic respiratory failure (ACRF). Among 53 consecutively intubated patients admitted for ACRF, we conducted a prospective, randomized controlled trial of weaning in 33 patients who failed a 2-h T-piece weaning trial (2 h-WT) although they met simple criteria for weaning. Conventional invasive pressure support ventilation (IPSV) was used as the control weaning technique in 16 patients (IPSV group), and NIV was applied immediately after extubation in 17 patients (NIV group). The two weaning groups were similar for type of chronic respiratory failure (CRF), pulmonary function data, age, Simplified Acute Physiology Score (SAPS II), and severity of ACRF on admission. The characteristics of the two groups were also similar at randomization. In the IPSV group, 12 of 16 patients (75%) were successfully weaned and extubated, versus 13 of 17 (76.5%) in the NIV group (p = NS). NIV like IPSV significantly and similarly improved gas exchange in relation to that achieved during 2 h-WT (p < 0.05). The duration of ETMV was significantly shorter in the NIV (4.56 +/- 1.85 d) than in the IPSV group (7.69 +/- 3.79 d) (p = 0. 004). NIV also reduced the mean period of daily ventilatory support, but increased the total duration of ventilatory support related to weaning (3.46 +/- 1.42 d, versus 11.54 +/- 5.24 d with NIV; p = 0. 0001). Most patients in the IPSV group developed complications related to ETMV and/or the weaning process, but the difference was not significant (nine of 16 versus six of 17). The durations of ICU and hospital stays and the 3-mo survival were similar in the two groups. In conclusion, NIV permits earlier removal of the endotracheal tube than with conventional IPSV, and reduces the duration of daily ventilatory support without increasing the risk of weaning failures. NIV should be considered as a new and useful systematic approach to weaning in patients with ACRF who are difficult to wean.