Use Of Noninvasive Positive Pressure Ventilation Research Articles

Outcomes of Patients With Acute Respiratory Failure After Abdominal Surgery Treated With Noninvasive Positive Pressure Ventilation

Little is known about the physiologic and clinical effects of noninvasive positive pressure ventilation (NPPV) in patients who have acute respiratory failure (ARF) after abdominal surgery. We evaluated our clinical experience with the use of NPPV in the treatment of ARF after abdominal surgery. We prospectively evaluated NPPV use during a 2-year period in a medical-surgical ICU of a university hospital. We documented demographic and diagnostic data, gas exchange, and clinical outcomes. We compared patients who were not intubated to those who were intubated after a trial of NPPV. Of 72 patients with ARF after abdominal surgery who were treated with NPPV, 48 patients avoided intubation (67%). Patients in the intubated and nonintubated groups had similar demographic characteristics, and similar American Society of Anesthesiologists physical status and simplified acute physiology score II scores at admission. The intubated group had a significantly lower Pa(O2)/fraction of inspired oxygen (Fi(O2)) ratio (123 +/- 62 mm Hg vs 194 +/- 76 mm Hg, p < 0.01) and more extended bilateral alveolar infiltrates (67% vs 31%, p < 0.01) than the non-intubated group. Within the first NPPV observation period, the Pa(O2)/Fi(O2) increased (+ 36 +/- 29% [+/- SD], p = 0.04) and the respiratory rate decreased (28.2 +/- 3.4 breaths/min vs 23.1 +/- 3.8 breaths/min, p < 0.01) significantly only in the non-intubated group. The non-intubated group had significantly lower length of ICU stay (17.3 +/- 10.9 days vs 34.1 +/- 28.5 days, p < 0.01) and mortality rate (6% vs 29%, p < 0.01). NPPV may be an alternative to conventional ventilation in selected patients with ARF after abdominal surgery who require ventilatory support.

20 Use of Noninvasive Positive Pressure Ventilation to Facilitate Extubation in Pediatric Patients with Neuromuscular Diseases.

Introduction: Patients with neuromuscular diseases (NMDs) who require intubation are at risk of extubation failure due to respiratory muscle weakness and they may require tracheostomy. Purpose: To evaluate the use of noninvasive positive pressure ventilation (NPPV) with the BiPAP® (Respironics) device to facilitate extubation of children with NMDs and poor baseline pulmonary function who have been intubated for acute respiratory failure or surgery. Methods: Retrospective chart review, IRB approved. Results: During the time period Jan 2001–Dec 2004, NPPV was used to facilitate extubation for 22 episodes of intubation in 14 patients. Diagnoses: Duchenne muscular dystrophy (Duchenne MD) (7 patients); type 1 spinal muscular atrophy (2 patients); Becker MD (1 patient); congenital MD (1 patient); nemaline myopathy (1 patient); polymyositis (1 patient); acid maltase deficiency (1 patient). Mean age at time of extubation (± SD): 10.7+ 5.9 years (range: 1–20 years); 11 of 14 patients were male. Four of 22 episodes of extubation were after spinal surgery. In these patients, mean baseline vital capacity was 47.3+ 11.4% predicted. In 18 episodes, extubation was after acute respiratory illness with respiratory failure. Mean baseline vital capacity for these patients: 24.5+ 9.1% predicted (range: 11–38%) (n=10, excludes spinal muscular atrophy infants). NPPV was used successfully to facilitate extubation in all 4 episodes of post-surgical extubaton. NPPV was successful in 17 of 18 episodes of extubation during acute respiratory illnesses (94% success rate). At follow-up (mean 27.5+ 15.2 months after extubation), 2 patients have died (1 patient had Duchenne MD and refused chronic NPPV, 1 patient had acid maltase deficiency). The remaining 12 patients are alive, 9 of whom have no tracheostomy and are using chronic home NPPV. The mean vital capacity at follow-up in these patients is 27.5+ 14.2% predicted. Two patients are now ventilated with tracheostomy tubes. Conclusion: Patients with severe neuromuscular diseases who have been intubated are at risk for extubation failure and the need for tracheostomy. Our study suggests that, despite highly impaired pulmonary function, NPPV can be used to extubate many of these patients successfully. On long-term follow-up, most of our patients have avoided tracheostomy. Further study is needed to optimize the use of NPPV for patients with NMDs.

The cost-effectiveness of early noninvasive ventilation for ALS patients

BackgroundOptimal timing of noninvasive positive pressure ventilation (NIPPV) initiation in patients with amyotrophic lateral sclerosis (ALS) is unknown, but NIPPV appears to benefit ALS patients who are symptomatic from pulmonary insufficiency. This has prompted research proposals of earlier NIPPV initiation in the ALS disease course in an attempt to further improve ALS patient quality of life and perhaps survival. We therefore used a cost-utility analysis to determine a priori what magnitude of health-related quality of life (HRQL) improvement early NIPPV initiation would need to achieve to be cost-effective in a future clinical trial.MethodsUsing a Markov decision analytic model we calculated the benefit in health-state utility that NIPPV initiated at ALS diagnosis must achieve to be cost-effective. The primary outcome was the percent utility gained through NIPPV in relation to two common willingness-to-pay thresholds: $50,000 and $100,000 per quality-adjusted life year (QALY).ResultsOur results indicate that if NIPPV begun at the time of diagnosis improves ALS patient HRQL as little as 13.5%, it would be a cost-effective treatment. Tolerance of NIPPV (assuming a 20% improvement in HRQL) would only need to exceed 18% in our model for treatment to remain cost-effective using a conservative willingness-to-pay threshold of $50,000 per QALY.ConclusionIf early use of NIPPV in ALS patients is shown to improve HRQL in future studies, it is likely to be a cost-effective treatment. Clinical trials of NIPPV begun at the time of ALS diagnosis are therefore warranted from a cost-effectiveness standpoint.

Facial side effects during noninvasive positive pressure ventilation in children

The study quantified the side effects of nasal masks use for noninvasive positive pressure ventilation (NPPV) in children. Cross-sectional retrospective study in a tertiary pediatric university hospital. Patients with obstructive sleep apnea (n=16), neuromuscular disorders (n=14), and cystic fibrosis (n=10). Clinical evaluation of facial tolerance. A skin injury was observed in 19 patients (48%), with a transient erythema in 7 (18%), prolonged erythema in 9 (23%), and skin necrosis in 3 (8%). Skin injury was associated with age over 10 years (OR=16) and use of a commercial mask (OR=15) and was less frequent in patients with obstructive sleep apnea. The change of a commercial mask for a custom-made mask was associated with reduction in the skin injury score. Global facial flattening was present in 68% of the patients. No correlation was observed with age, daily or cumulative use of NPPV, or the type of mask. A maxillary retrusion was present in 37% of patients. No correlation was observed with age or the type of mask or the underlying disease, but an association was found with a longer daily use of NPPV (OR=6.3). The prevalence of facial side effects is clinically significant in children using NPPV. Systematic maxillofacial follow-up enables these effects to be identified. Remedial measures could include the change of the interface or reducing the daily use of NPPV.

L’assistance ventilatoire non invasive à domicile chez l’enfant

Non-invasive positive pressure ventilation (NPPV) represents a particularly interesting technique of ventilatory support in paediatrics. Indeed, a significant number of pathologies that may be responsible for chronic respiratory insufficiency in childhood, such as neuromuscular diseases, obstruction of the upper airways, disorders of chest wall and/or the lungs, and disorders of ventilatory control may all lead to alveolar hypoventilation that can be improved by ventilatory support.Few physiological studies have been performed on NPPV in children. The most appropriate modes and settings for each pathology have not been clearly defined, and the criteria for commencing NPPV are based essentially on consensus guidelines for the management of neuromuscular disorders.All the health care professionals managing these children should combine their efforts to evaluate more precisely the medium and long-term physiological effects of NPPV on the respiratory muscles, the development of the respiratory system, inspiratory activity, the indications for starting treatment and, above all, the benefits in terms of psycho-neurological development and quality of life.A better evaluation of the medium and long-term physiological and psychological benefits together with technical improvements in ventilators and associated equipment should allow a rapid expansion in the use of domiciliary NPPV in children.

Does noninvasive positive pressure ventilation improve outcome in acute hypoxemic respiratory failure? A systematic review

The results of studies on noninvasive positive pressure ventilation (NPPV) for acute hypoxemic respiratory failure unrelated to cardiogenic pulmonary edema have been inconsistent. To assess the effect of NPPV on the rate of endotracheal intubation, intensive care unit and hospital length of stay, and mortality for patients with acute hypoxemic respiratory failure not due to cardiogenic pulmonary edema. We searched the databases of MEDLINE (1980 to October 2003) and EMBASE (1990 to October 2003). Additional data sources included the Cochrane Library, personal files, abstract proceedings, reference lists of selected articles, and expert contact. We included studies if a) the design was a randomized controlled trial; b) patients had acute hypoxemic respiratory failure not due to cardiogenic pulmonary edema; c) the interventions compared noninvasive ventilation and standard therapy with standard therapy alone; and d) outcomes included need for endotracheal intubation, length of intensive care unit or hospital stay, or intensive care unit or hospital survival. In duplicate and independently, we abstracted data to evaluate methodological quality and results. The addition of NPPV to standard care in the setting of acute hypoxemic respiratory failure reduced the rate of endotracheal intubation (absolute risk reduction 23%, 95% confidence interval 10-35%), ICU length of stay (absolute reduction 2 days, 95% confidence interval 1-3 days), and ICU mortality (absolute risk reduction 17%, 95% confidence interval 8-26%). However, trial results were significantly heterogeneous. Randomized trials suggest that patients with acute hypoxemic respiratory failure are less likely to require endotracheal intubation when NPPV is added to standard therapy. However, the effect on mortality is less clear, and the heterogeneity found among studies suggests that effectiveness varies among different populations. As a result, the literature does not support the routine use of NPPV in all patients with acute hypoxemic respiratory failure.

Noninvasive Ventilation by Helmet or Face Mask in Immunocompromised Patients: A Case-Control Study

To compare the efficacy of noninvasive positive pressure ventilation (NPPV) by helmet and face mask in immunocompromised patients with hypoxemic acute respiratory failure (ARF). Case-control study. The general ICU of a university hospital. Nineteen immunocompromised patients (hematologic malignancies [n = 8], solid-organ recipients [n = 8], AIDS [n = 3]) with hypoxemic ARF, fever, and lung infiltrates were treated with NPPV delivered by a helmet. Nineteen immunocompromised patients matched for diagnosis, age, simplified acute physiology score II, and Pao(2)/fraction of inspired oxygen (Fio(2)) receiving NPPV through a facial mask served as case-control subjects. The use of NPPV delivered via helmet was as effective as NPPV delivered via face mask in avoiding endotracheal intubations (intubation rate, 37% vs 47%, respectively; p = 0.37) and improving gas exchange; 14 patients (74%) in the helmet group showed a sustained improvement in Pao(2)/Fio(2) ratio (ability to increase Pao(2)/Fio(2) ratio > 200, or an increase > 100 from the baseline) in comparison with 7 patients (34%) in the mask group (p = 0.02), whose Pao(2)/Fio(2) at treatment discontinuation was higher (p = 0.02) and had fewer complications related to NPPV (ie, skin necrosis, p = 0.01). Moreover, the patients receiving ventilation via helmet required significantly less NPPV discontinuations in the first 24 h of application (p < 0.001) than patients receiving ventilation via face mask. The helmet may represent a valid alternative to a face mask in immunocompromised patients with lung infiltrates and hypoxemic ARF, increasing the patient's tolerance (ie, the number of hours of continuous NPPV use without interruptions) and decreasing the rate of complications directly related to the administration of NPPV.

Non-invasive positive pressure ventilation in acute hypercapnic respiratory failure: clinical experience of a respiratory ward

Although a controlled trial demonstrated that non-invasive positive pressure ventilation (NIV) can be successfully applied to a respiratory ward (RW) for selected cases of acute hypercapnic respiratory failure (AHRF), clinical practice data about NIV use in this setting are limited. The aim of this observational study is to assess the feasibility and efficacy of NIV applied to AHRF in a RW in everyday practice. Twenty-two percent (216/984) of patients consecutively admitted for AHRF to our RW in Arezzo (years: 1996-2003) received NIV in addition to standard therapy, according to pre-defined routinely used criteria. Tolerance, effects upon arterial blood gases (ABG), success rate (avoidance a priori criteria for intubation) and predictors of failure of NIV were analysed. Nine patients (4.2%) were found to be intolerant to NIV, while the remaining 207 (M: 157, F: 50; mean (SD) age: 73.2 (8.9) yrs; COPD: 71.5%) were ventilated for >1 hour. ABG significantly improved after two hours of NIV (pH: 7.32 (0.06) versus median (Interquartiles) 7.28 (7.24-7.31), p<0.0001; PaCO2: 71.9 (13.5) mmHg versus 80.0 (15.2) mmHg, p<0.0001; PaO2/FiO2: 212 (66) versus 184 (150-221), p<0.0001). NIV succeeded in avoiding intubation in 169/207 patients (81.6%) with hospital mortality of 15.5%. NIV failure was independently predicted by Activity of Daily Living score, pneumonia as cause of AHRF and Acute Physiology and Chronic Health Evaluation III score. In clinical practice NIV is feasible, effective in improving ABG and useful in avoiding intubation in most AHRF episodes that do not respond to the standard therapy managed in an RW adequately trained in NIV.

Noninvasive mechanical ventilation in patients with stable severe COPD

Noninvasive positive pressure ventilation in patients with stable chronic obstructive pulmonary disease. The role of non-invasive positive pressure ventilation (NIPPV) is well documented in patients with restrictive thoracic diseases like kyphoscoliosis, tuberculosis sequelae or neuromuscular disease. There is also a good evidence for the use of NIPPV in acute respiratory failure in patients with an exacerbation of COPD. The application of NIPPV in patients with chronic respiratory failure is growing, but there is less evidence than in restrictive disorders. NIPPV can unload the respiratory muscles in patients with chronic hypercapnic COPD and so alleviates fatigue of the respiratory pump, but improvement in the maximal inspiratory pressure (Pi (max)) is small or even absent. An improvement of sleep quality has also postulated, there was an increase in total sleep time and sleep effectiveness when using higher inspiratory pressure. An increase of the walking distance was shown in short term studies, only. In most studies, there was an increase in quality of life as a main topic. Mortality was unchanged in the two long-term randomised controlled studies. Current data suggest a possible role of NIPPV in patients with severe hypercapnia. A high effective inspiratory pressure and a ventilator mode with a significant reduction in the work of breathing should be choosen. NIPPV should be started in hospital, a close reassessment must be performed. Patients who accepted NIPPV in the first weeks had a good compliance for long-term use.

Use of noninvasive ventilation in patients with amyotrophic lateral sclerosis

Noninvasive positive pressure ventilation (NIPPV) is associated with improved survival in amyotrophic lateral sclerosis (ALS) and has been widely recommended. The extent of NIPPV use in ALS patients and the factors associated with its use have not been studied. A cross-sectional study using the ALS Patient Care Database. Analyses were performed to assess the association of patient and care characteristics with use of ventilatory support. 1458 patients were studied. 15.6% used NIPPV and 2.1% used invasive mechanical ventilation. Patients who used NIPPV were significantly more likely to be male and have higher income than those who did not. They were also more likely to have a gastrostomy tube, lower vital capacity, more severe disease, bulbar involvement and poorer general health status as measured by the SF-12 and Sickness Impact Profile. Multivariate analysis revealed that lower FVC, higher income and use of gastrostomy tube were independently associated with use of NIPPV. NIPPV is used more than seven times as frequently as invasive ventilation in ALS patients. Patients who use NIPPV have more severe disease than those who do not use any respiratory intervention. Patients with lower income are less likely to use NIPPV, which raises concerns about disparities in the care of patients with ALS.

Noninvasive positive pressure ventilation as a weaning strategy for intubated adults with respiratory failure.

Noninvasive positive pressure ventilation (NPPV) provides ventilatory support without the need for an invasive airway. Interest has emerged in using NPPV to facilitate earlier removal of the endotracheal tube and decrease complications associated with prolonged intubation. To summarize the evidence comparing NPPV and invasive positive pressure ventilation (IPPV) weaning on clinical outcomes in intubated adults with respiratory failure. We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library, issue 2, 2003), MEDLINE (January 1966 to July 2003) and EMBASE (January 1980 to July 2003) for randomized controlled trials comparing NPPV and IPPV weaning. Additional data sources included personal files, conference proceedings and author contact. Randomized and quasi-randomized studies comparing early extubation with immediate application of NPPV to IPPV weaning in intubated adults with respiratory failure. Two reviewers independently assessed trial quality and abstracted data according to prespecified criteria. Sensitivity and subgroup analyses were planned to assess the impact of (i) excluding quasi-randomized trials and (ii) the etiology of respiratory failure on outcomes. We identified eleven trials, of which five were included, involving 171 participants with predominantly chronic obstructive pulmonary disease. Overall, the included studies were of moderate to good quality. Compared to the IPPV strategy, the NPPV strategy decreased mortality (RR 0.41, 95% CI 0.22 to 0.76), the incidence of ventilator associated pneumonia (RR 0.28, 95% CI 0.09 to 0.85), intensive care unit length of stay (WMD -6.88 days, 95% CI -12.60 to -1.15), hospital length of stay (WMD -7.33 days, 95%CI -14.05 to -0.61), total duration of mechanical support (WMD -7.33 days, 95% CI -11.45 to -3.22) and the duration of endotracheal mechanical ventilation (WMD -6.79 days, 95% CI -11.70 to -1.87). There was no effect of NPPV on weaning failures or the duration of mechanical support related to weaning and insufficient data to pool adverse events or quality of life. Excluding a single quasi-randomized trial maintained the significant reduction in mortality and ventilator associated pneumonia. Subgroup analyses suggested that the mortality benefit of the NPPV approach is greater in patients with chronic obstructive pulmonary disease. Summary estimates from five studies of moderate to good quality demonstrated a consistent positive effect on overall mortality. At present, use of NPPV to facilitate weaning in mechanically ventilated patients, with predominantly chronic obstructive lung disease, is associated with promising, although insufficient, evidence of net clinical benefit.

Longitudinal effects of noninvasive positive-pressure ventilation in patients with amyotrophic lateral sclerosis.

To evaluate the duration of benefit on symptoms, quality of life, and survival derived from the use of noninvasive positive-pressure ventilation by patients with amyotrophic lateral sclerosis. In this prospective, cohort study, 30 of 36 consecutively referred symptomatic patients tolerated nightly noninvasive positive-pressure ventilation and undertook pulmonary function testing and 12 symptom and quality-of-life instruments concerning sleep quality, daytime sleepiness, physical fatigue, mental fatigue, and depression that were administered during a 10-mo period. With treatment, there was a significant improvement in the majority of patients in sleep quality, daytime sleepiness, physical fatigue, and depression; however, significant improvements lasted for up to 10 mo only in sleep quality. Partial pressure of arterial oxygen, partial pressure of arterial carbon dioxide, and oxyhemoglobin saturation remained stable or even improved for up to 7 mo during use of part-time noninvasive positive-pressure ventilation. A total of 14 patients had survival prolonged by continuous dependence on noninvasive positive-pressure ventilation. Noninvasive positive-pressure ventilation provides a long-lasting benefit on symptoms and quality of life indicators for amyotrophic lateral sclerosis patients and should be offered to all patients with symptoms of sleep disordered breathing or inspiratory muscle dysfunction. It can also prolong tracheostomy-free survival.

Noninvasive Positive Pressure Ventilation for Acute Respiratory Failure in Emergency Department: a Qualitative Review

The roles of noninvasive positive pressure ventilation (NIPPV) as a treatment modality for patients presenting with acute respiratory failure (ARF) to the emergency department (ED) have not been clearly identified. The major advantages of NIPPV are avoiding patient's discomforts and complications relating to endotracheal intubation and mechanical ventilation. This review is to explore the current evidence on the effectiveness of NIPPV in various subgroups of patients with ARF. The rationales, advantages, complications and contraindications in the usage of NIPPV will also be discussed. There is robust evidence to support the use of NIPPV in severe acute exacerbation of chronic obstructive airway disease (COAD). A modest amount of favourable evidence supports the use of Continuous Positive Airway Pressure (CPAP) in cardiogenic pulmonary oedema, although the potential for harm has not been excluded. There exists no solid evidence supporting the use of NIPPV in asthma and pneumonia. Early institution of NIPPV in the ED is appropriate, feasible, likely to be beneficial and without major complications. Further good quality studies to evaluate the roles of NIPPV for ARF in the ED setting are needed to define which groups of patients can gain most benefit from this type of treatment.

Evaluation of a Practice Guideline for Noninvasive Positive-Pressure Ventilation for Acute Respiratory Failure

Clinical practice guidelines have been devised to change practitioner performance and to improve the process and outcomes of care. The objective of this study was to determine whether adherence to a practice guideline on noninvasive positive-pressure ventilation (NPPV) for the treatment of patients with acute respiratory failure (ARF) would change clinician behavior and resource utilization, and improve NPPV utilization and patient outcomes. Using a multidisciplinary team, we developed, implemented, and evaluated an NPPV practice guideline for ARF. Before and after guideline implementation, we recorded the incidence of endotracheal intubation (ETI) and mortality. Secondary outcomes were technological settings (ie, NPPV settings and duration) and NPPV administration (ie, cardiopulmonary monitoring, transfer to and time spent in the ICU, and pulmonary consultation). We enrolled 189 patients, 91 in the preguideline phase and 98 in the postguideline phase. Patients were similar in the both phases with respect to diagnoses at hospital admission and severity of illness. Of patients receiving NPPV for ARF, 67.3% fulfilled the guideline eligibility criteria in the postguideline phase compared to 62.6% in the preguideline phase (p = 0.543). Compared to the preguideline phase, more patients in the postguideline phase were transferred to the ICU (14.7% vs 33.7%, respectively; p = 0.003), spent more time in the ICU (30.9% vs 62.4%, respectively; p < 0.0001), and had consultation by a pulmonary physician (28.4% vs 49.0%, respectively; p = 0.004). There were no changes in technological settings. Guideline implementation was associated with improved cardiopulmonary monitoring. Nursing and respiratory therapist flow sheets were well-utilized during the guideline phase. There were no differences in ETI rates and mortality rates before and after guideline implementation. In this before-after study, we found that a multidisciplinary guideline for the use of NPPV for the treatment of patients with ARF was associated with changes in the process of care, with greater NPPV utilization in the ICU, and with increased pulmonary consultation, without any significant changes in the outcomes of care (ie, ETI and mortality rates).

Noninvasive ventilation in the pediatric intensive care unit for children with acute respiratory failure.

Noninvasive ventilation, a novel treatment to increase alveolar ventilation, is accomplished with either subatmospheric or positive pressure administered via an external interface. In adults with acute respiratory failure, noninvasive positive pressure ventilation (NPPV) is superior to standard therapy in preventing intubation and reducing mortality. The role of NPPV in pediatric-age patients with acute respiratory distress is not as well established. Early case reports showed that NPPV treatment does acutely improve both the clinical manifestations of respiratory distress and respiratory gas exchange in children with respiratory distress. However, it is not clear whether NPPV in this setting can prevent vs. delay endotracheal intubation. Other uses of NPPV in the pediatric intensive care unit include the treatment of upper airway obstruction, atelectasis, and exacerbations of neuromuscular disorders, and to facilitate weaning from invasive mechanical ventilation. Successful use of NPPV in young infants with respiratory distress is impeded by the lack of suitable size interfaces, and the response characteristics of commercially available bilevel ventilators. Despite these challenges, NPPV is a promising alternate to standard therapies in the treatment of acute respiratory distress in the pediatric-age patient.

Health technology assessment in the ICU: Noninvasive positive pressure ventilation for acute respiratory failure

Critical care practitioners have a number of health-related technologies at our disposal to provide the best possible care for our critically ill patients. Although certain technologies may improve outcomes in the intensive care unit (ICU), many technologies are disseminated without rigorous evaluation. Health technology assessment (HTA) in critical care is a complex and dynamic process, which is a powerful tool to assess a health technology for its initial use or continued application in the ICU. This article applies an HTA framework to the use of noninvasive positive pressure ventilation (NPPV) for patients with acute respiratory failure (ARF). The strongest evidence to date supports the use of NPPV in patients with ARF caused by exacerbations of chronic obstructive pulmonary disease (COPD); the benefit for patients with acute nonhypercarbic, hypoxemic respiratory failure is less clear. The success of NPPV technology depends on operator education and experience. The cost effectiveness of NPPV has been evaluated in patients with ARF caused by COPD, and cost reduction is attributed to the prevention of ventilator-associated pneumonia by avoiding endotracheal intubation. An HTA framework can help health care practitioners make important decisions regarding the acquisition of new technologies and the evaluation of current technologies. Careful evaluation of health technologies in the ICU should be an ongoing priority. Copyright 2003 Elsevier, Inc. All rights reserved.

Noninvasive ventilation in chronic obstructive pulmonary disease, bronchiectasis and cystic fibrosis.

Although long-term oxygen therapy (LTOT) improves survival, it has little effect on hypoventilation and other outcomes in patients with hypercapnic respiratory failure due to chronic obstructive pulmonary disease (COPD). Recent studies have shown that the use of noninvasive positive-pressure ventilation, when used in combination with LTOT in selected stable COPD patients, controls hypoventilation and improves daytime arterial blood gases, sleep quality, health status and may have a benefit in reducing exacerbation frequency and severity. Patients who show the greatest reduction in overnight carbon dioxide tension in arterial blood with ventilation are most likely to benefit from long-term ventilatory support. Some benefits have also been shown in patients with chronic respiratory failure due to bronchiectasis and cystic fibrosis, though survival is inferior in this patient group. As most studies of noninvasive positive-pressure ventilation in chronic obstructive pulmonary disease have been relatively short term, large multicentre studies with survival, exacerbations and hospital admissions as the primary end points are required to evaluate longer term effects.

Noninvasive Positive-Pressure Ventilation vs Conventional Oxygen Supplementation in Hypoxemic Patients Undergoing Diagnostic Bronchoscopy

We have reported previously on the use of noninvasive positive-pressure ventilation (NPPV) to assist spontaneous breathing in high-risk hypoxemic patients (i.e., PaO(2)/fraction of inspired oxygen [FIO(2)] ratio, < or = 100) who are undergoing diagnostic fiberoptic bronchoscopy (FOB). The efficacy of this intervention in patients with less severe forms of hypoxemia (i.e., PaO(2)/FIO(2) ratio, < 200) is unknown. Twenty-six patients with PaO(2)/FIO(2) ratios < or = 200 who required bronchoscopic BAL for suspected nosocomial pneumonia were entered into the study. Thirteen patients were randomized during FOB to receive NPPV, and 13 patients were randomized to receive conventional oxygen supplementation by Venturi mask. The primary end points were changes in the PaO(2)/FIO(2) ratio during FOB and within 60 min of terminating the procedure. RESULTS AND OUTCOME: At study entry, the two groups were similar in terms of age, simplified acute physiologic score II values, and cardiorespiratory parameters. During FOB, the mean (+/- SD) PaO(2)/FIO(2) ratio increased by 82% in the NPPV group (261 +/- 100 vs 139 +/- 38; p < 0.001) and decreased by 10% in the conventional oxygen supplementation group (155 +/- 24 to 139 +/- 38; p = 0.23). Sixty minutes after undergoing FOB, the NPPV group had a higher mean PaO(2)/FIO(2) ratio (176 +/- 62 vs 140 +/- 38; p = 0.09), a lower mean heart rate (91 +/- 18 vs. 108 +/- 15 beats/min; p = 0.02), and no reduction in mean arterial pressure in comparison to a 15% decrease from the baseline in the control group. One patient in the NPPV group and two patients in the control group required nonemergent intubation. Major bacterial isolates included Staphylococcus aureus (7 of 30 isolates; 23%) and Pseudomonas aeruginosa (12 of 30 isolates; 40%). In patients with severe hypoxemia, NPPV is superior to conventional oxygen supplementation in preventing gas-exchange deterioration during FOB with better hemodynamic tolerance.

Noninvasive positive-pressure ventilation in pediatric status asthmaticus.

OBJECTIVE: To describe the use of noninvasive positive-pressure ventilation in children with status asthmaticus. DESIGN: Brief report. SETTING: Pediatric intensive care unit in two tertiary institutions. SUBJECTS: Children with severe acute asthma and hypercarbic respiratory failure. INTERVENTIONS: Noninvasive positive-pressure ventilation using a bilevel positive-pressure (BIPAP) device. MEASUREMENTS AND MAIN RESULTS: Three children, ages 9, 11, and 15 yrs, were treated for hypercarbic respiratory failure caused by status asthmaticus by using BIPAP. The duration of pediatric intensive care unit admission was 48 hrs, and the duration of therapy ranged from 12 to 17 hrs. Inspiratory positive airway pressure ranged from 10 to 14 cm H(2)O (0.98-1.37 kPa), with a mean of 12 cm H(2)O (1.18 kPa). Expiratory positive airway pressure ranged from 4 to 5 cm H(2)O (0.39-0.49 kPa), with a mean of 5 cm H(2)O (0.49 kPa). Pulse oximetry was monitored continuously until resolution of symptoms. The mean values for respiratory rate, pH, and CO(2) tension were compared at initiation, 3-4 hrs, and >12 hrs after beginning BIPAP. BIPAP treatment resulted in improved ventilatory status as shown by an increase in pH from a mean of 7.26 on admission to 7.38 after 3-4 hrs and after 12 hrs, respectively. However, respiratory rate showed a steady decrease from a mean of 31.7 breaths/min on admission to 24 breaths/min at 3-4 hrs and 19 breaths/min at >12 hrs of BIPAP therapy. CO(2) tension (Pco(2)) decreased from a mean value of 54.6 mm Hg (7.28 kPa) on admission to 36.4 mm Hg (4.85 kPa) at 3-4 hrs of treatment; the mean Pco(2) after >12 hrs of treatment was 39.8 mm Hg (5.31 kPa). CONCLUSION: In three children with status asthmaticus, BIPAP seemed to improve ventilation and gas exchange, culminating in resolution of hypercarbic respiratory failure. A prospective, randomized, and controlled study is required to determine its role in pediatric status asthmaticus.

Ventilação não-invasiva com pressão positiva em pacientes com insuficiência respiratória aguda: fatores associados à falha ou ao sucesso

Objetivo: Determinar a eficiência da ventilação não-invasiva com pressão positiva (VNIPP) na insuficiência respiratória aguda e identificar fatores associados ao sucesso ou falha. Pacientes e métodos: Estudo aberto e prospectivo analisando 60 episódios de uso de VNIPP em 53 pacientes em insuficiência respiratória. Resultados: Em 37 episódios (62%) obteve-se sucesso sem intubação (grupo Sucesso, GS), enquanto em 23 ocasiões (38%) os pacientes foram intubados (grupo Falha, GF). Os pacientes do GF apresentaram escore de Apache II mais elevado do que os do GS (30,4 ± 9 versus 22,2 ± 8, p = 0,001). Após 2h de VNIPP houve redução da freqüência respiratória, sendo menos intensa no GF (de 33 ± 9 para 30 ± 8irpm, p = 0,094) do que no GS (de 39 ± 11 para 28 ± 9irpm, p &lt; 0,001). Houve aumento da PaO2 (de 62 ± 22 para 101 ± 65mmHg, p &lt; 0,001), sem diferenças entre os grupos. Nos pacientes com hipercapnia houve redução da PaCO2 no GS (de 76 ± 20 para 68 ± 21mmHg, p = 0,032) e não no GF (de 89 ± 23 para 93 ± 40mmHg, p = 0,54). O pH se elevou de 7,25 ± 0,10 e 7,34 ± 0,11, p = 0,007 no GS, mas não no GF (7,24 ± 0,07 e 7,21 ± 0,12, p = 0,48). A VNIPP foi utilizada por mais tempo no GS (3,4 ± 2,5 versus 2,3 ± 2 dias, p = 0,003) e com níveis mais altos de pressão respiratória positiva em via aérea (IPAP) (13,2 ± 3 versus 11 ± 4cmH2O, p = 0,02). Dez pacientes (17%) foram a óbito, todos no GF. A complicação mais freqüente foi lesão de pele no ponto de contato da máscara com o nariz (5, 8%). A VNIPP foi eficiente no tratamento da insuficiência respiratória aguda em cerca de 2/3 das vezes. Pacientes mais graves, menor eficiência em reduzir a freqüência respiratória, em reverter a acidose respiratória e o uso de níveis relativamente mais baixos de pressão respiratória positiva em via aérea (IPAP) associaram-se à falha. A alta mortalidade (10, 43%) nos casos de falha justifica esforços para otimizar sua utilização e ao mesmo tempo para reconhecer precocemente suas falhas, evitando-se protelar a intubação traqueal.