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Importance: The optimal screening frequency and spontaneous breathing trial (SBT) technique to liberate adults from ventilators are unknown., Objective: To compare the effects of screening frequency (once-daily screening vs more frequent screening) and SBT technique (pressure-supported SBT with a pressure support level that was >0-≤8 cm H2O and a positive end-expiratory pressure [PEEP] level that was >0-≤5 cm H2O vs T-piece SBT) on the time to successful extubation., Design, Setting, and Participants: Randomized clinical trial with a 2 × 2 factorial design including critically ill adults who were receiving invasive mechanical ventilation for at least 24 hours, who were capable of initiating spontaneous breaths or triggering ventilators, and who were receiving a fractional concentration of inspired oxygen that was 70% or less and a PEEP level of 12 cm H2O or less. Recruitment was between January 2018 and February 2022 at 23 intensive care units in North America; last follow-up occurred October 18, 2022., Interventions: Participants were enrolled early to enable protocolized screening (more frequent vs once daily) to identify the earliest that patients met criteria to undergo pressure-supported or T-piece SBT lasting 30 to 120 minutes., Main Outcome and Measures: Time to successful extubation (time when unsupported, spontaneous breathing began and was sustained for ≥48 hours after extubation)., Results: Of 797 patients (198 in the once-daily screening and pressure-supported SBT group, 204 in once-daily screening and T-piece SBT, 195 in more frequent screening and pressure-supported SBT, and 200 in more frequent screening and T-piece SBT), the mean age was 62.4 (SD, 18.4) years and 472 (59.2%) were men. There were no statistically significant differences by screening frequency (hazard ratio [HR], 0.88 [95% CI, 0.76-1.03]; P = .12) or by SBT technique (HR, 1.06 [95% CI, 0.91-1.23]; P = .45). The median time to successful extubation was 2.0 days (95% CI, 1.7-2.7) for once-daily screening and pressure-supported SBT, 3.1 days (95% CI, 2.7-4.8) for once-daily screening and T-piece SBT, 3.9 days (95% CI, 2.9-4.7) for more frequent screening and pressure-supported SBT, and 2.9 days (95% CI, 2.0-3.1) for more frequent screening and T-piece SBT. An unexpected interaction between screening frequency and SBT technique required pairwise contrasts that revealed more frequent screening (vs once-daily screening) and pressure-supported SBT increased the time to successful extubation (HR, 0.70 [95% CI, 0.50-0.96]; P = .02). Once-daily screening and pressure-supported SBT (vs T-piece SBT) did not reduce the time to successful extubation (HR, 1.30 [95% CI, 0.98-1.70]; P = .08)., Conclusions and Relevance: Among critically ill adults who received invasive mechanical ventilation for more than 24 hours, screening frequency (once-daily vs more frequent screening) and SBT technique (pressure-supported vs T-piece SBT) did not change the time to successful extubation. However, an unexpected and statistically significant interaction was identified; protocolized more frequent screening combined with pressure-supported SBTs increased the time to first successful extubation., Trial Registration: ClinicalTrials.gov Identifiers: NCT02399267 and NCT02969226.

Traditionally, nasal oxygen therapy has been delivered at low flows through nasal cannulae. In recent years, nasal cannulae designed to administer heated and humidified air/oxygen mixtures at high flows (up to 60 L/min) have been gaining popularity. These high-flow nasal cannula (HFNC) systems enhance patient comfort and tolerance compared with traditional high-flow oxygenation systems, such as nasal masks and nonrebreathing systems. By delivering higher flow rates, HFNC systems are less apt than traditional oxygenation systems to permit entrainment of room air during patient inspiration. Combined with the flushing of expired air from the upper airway during expiration, these mechanisms assure more reliable delivery of high Fio2 levels. The flushing of upper airway dead space also improves ventilatory efficiency and reduces the work of breathing. HFNC also generates a positive end-expiratory pressure (PEEP), which may counterbalance auto-PEEP, further reducing ventilator work; improve oxygenation; and provide back pressure to enhance airway patency during expiration, permitting more complete emptying. HFNC has been tried for multiple indications, including secretion retention, hypoxemic respiratory failure, and cardiogenic pulmonary edema, to counterbalance auto-PEEP in patients with COPD and as prophylactic therapy or treatment of respiratory failure postsurgery and postextubation. As of yet, very few high-quality studies have been published evaluating these indications, so recommendations regarding clinical applications of HFNC remain tentative.

Background: This study determined actual utilization rates and outcomes of noninvasive positive pressure ventilation (NIV) at selected hospitals that had participated in a prior survey on NIV use., Methods: This observational cohort study, based at eight acute care hospitals in Massachusetts, focused on all adult patients requiring ventilatory support for acute respiratory failure during predetermined time intervals., Results: Of 548 ventilator starts, 337 (61.5%) were for invasive mechanical ventilation and 211 (38.5%) were for NIV, with an overall NIV success rate of 73.9% (ie, avoidance of intubation or death while on NIV or within 48 h of discontinuation). Causal diagnoses for respiratory failure were classified as (I) acute-on-chronic lung disease (23.5%), (II) acute de novo respiratory failure (17.9%), (III) neurologic disorders (19%), (IV) cardiogenic pulmonary edema (16.8%), (V) cardiopulmonary arrest (12.2%), and (VI) others (10.6%). NIV use and success rates for each of the causal diagnoses were, respectively, (I) 76.7% and 75.8%, (II) 37.8% and 62.2%, (III) 1.9% and 100%, (IV) 68.5% and 79.4%, (V) none, and (VI) 17.2% and 60%. Hospital mortality rate was higher in patients with invasive mechanical ventilation than in patients with NIV (30.3% vs 16.6%, P < .001)., Conclusions: NIV occupies an important role in the management of acute respiratory failure in acute care hospitals in selected US hospitals and is being used for a large majority of patients with acute-on-chronic respiratory failure and acute cardiogenic pulmonary edema. NIV use appears to have increased substantially in selected US hospitals over the past decade., Trial Registry: ClinicalTrials.gov; No.: NCT00458926; URL: www.clinicaltrials.gov.

Background: We hypothesized that the total face mask (TFM) would be perceived as more comfortable than a standard oronasal mask (ONM) by patients receiving noninvasive mechanical ventilation (NIV) therapy for acute respiratory failure (ARF) and would be quicker to apply by respiratory therapists., Methods: Sixty patients presenting with ARF were randomized to receive NIV via either an ONM or a TFM. Mask comfort and dyspnea were assessed using visual analog scores. Other outcomes included time required to apply, vital signs and gas exchange at set time points, and early NIV discontinuation rates (ie, stoppage while still requiring ventilatory assistance)., Results: Mask comfort and dyspnea scores were similar for both groups through 3 h of use. The time required to apply the mask (5 min [interquartile range (IQR), 2-8] vs 3.5 min [IQR, 1.9-5]), and duration of use (15.7 h [IQR, 4.0-49.8]) vs 6.05 h [IQR, 0.9-56.7]) were not significantly different between the ONM and the TFM group, respectively. Except for heart rate, which was higher at baseline in the TFM group, no differences in vital signs or gas exchange were detected between the groups during the first 3 h (P > .05). Early NIV discontinuation rates were similar for both the ONM group and TFM group (40% vs 57.1%); however, eight patients in the TFM group were switched to an ONM within 3 h, and none from the ONM group was switched to a TFM (P < .05)., Conclusions: Among patients with ARF requiring NIV, the ONM and TFM were perceived to be equally comfortable and had similar application times. Early NIV discontinuation rates, improvements in vital signs and gas exchange, and intubation and mortality rates were also similar., Trial Registry: ClinicalTrials.gov; No.: NCT00686257; URL: www.clinicaltrials.gov.

Background: Noninvasive positive-pressure ventilation (NPPV) modes are currently available on bilevel and ICU ventilators. However, little data comparing the performance of the NPPV modes on these ventilators are available., Methods: In an experimental bench study, the ability of nine ICU ventilators to function in the presence of leaks was compared with a bilevel ventilator using the IngMar ASL5000 lung simulator (IngMar Medical; Pittsburgh, PA) set at a compliance of 60 mL/cm H(2)O, an inspiratory resistance of 10 cm H(2)O/L/s, an expiratory resistance of 20 cm H(2)O/ L/s, and a respiratory rate of 15 breaths/min. All of the ventilators were set at 12 cm H(2)O pressure support and 5 cm H(2)O positive end-expiratory pressure. The data were collected at baseline and at three customized leaks., Main Results: At baseline, all of the ventilators were able to deliver adequate tidal volumes, to maintain airway pressure, and to synchronize with the simulator, without missed efforts or auto-triggering. As the leak was increased, all of the ventilators (except the Vision [Respironics; Murrysville, PA] and Servo I [Maquet; Solna, Sweden]) needed adjustment of sensitivity or cycling criteria to maintain adequate ventilation, and some transitioned to backup ventilation. Significant differences in triggering and cycling were observed between the Servo I and the Vision ventilators., Conclusions: The Vision and Servo I were the only ventilators that required no adjustments as they adapted to increasing leaks. There were differences in performance between these two ventilators, although the clinical significance of these differences is unclear. Clinicians should be aware that in the presence of leaks, most ICU ventilators require adjustments to maintain an adequate tidal volume.

Noninvasive ventilation (NIV) has assumed an important role in the management of certain types of respiratory failure in acute-care hospitals. However, the optimal location for NIV has been a matter of debate. Some have argued that all patients begun on NIV in the acute-care setting should go to an intensive care unit (ICU), but this is impractical because ICU beds are often unavailable, and it may not be a sensible use of resources. Also, relatively few studies have examined the question of location for NIV. One problem is that various units' capabilities to deliver NIV differ substantially, even in the same hospital. Choosing the appropriate environment for NIV requires consideration of the patient's need for monitoring, the monitoring capabilities of the unit, including both technical and personnel resources (nursing and respiratory therapy), and the staff's skill and experience. In some hospitals NIV is begun most often in the emergency department, but is most often managed in an ICU. Step-down units are often good locations for NIV, but many institutions do not have step-down units. With ICU beds at a premium, many hospitals are forced to manage some NIV patients on general wards, which can be safely done with more stable patients if the ward is suitably monitored and experienced. When deciding where to locate the patient, clinicians must be familiar with the capabilities of the units in their facility and try to match the patient's need for monitoring and the unit's capabilities.

Objective: We recently reported a high success rate using noninvasive positive pressure ventilation (NPPV) to treat COPD exacerbations with hypercapnic encephalopathy. This study compared the hospital outcomes of NPPV vs. conventional mechanical ventilation (CMV) in COPD exacerbations with moderate to severe hypercapnic encephalopathy, defined by a Kelly score of 3 or higher., Design and Setting: A 3-year prospective matched case-control study in a respiratory semi-intensive care unit (RSICU) and intensive care unit (ICU)., Patients and Participants: From 103 consecutive patients the study included 20 undergoing NPPV and 20 CMV, matched for age, simplified acute physiology score II, and baseline arterial blood gases., Measurements and Results: ABG significantly improved in both groups after 2 h. The rate of complications was lower in the NPPV group than in the CMV group due to fewer cases of nosocomial pneumonia and sepsis. In-hospital mortality, 1-year mortality, and tracheostomy rates were similar in the two groups. Fewer patients remained on ventilation after 30 days in NPPV group. The NPPV group showed a shorter duration of ventilation., Conclusions: In COPD exacerbations with moderate to severe hypercapnic encephalopathy, the use of NPPV performed by an experienced team compared to CMV leads to similar short and long-term survivals with a reduced nosocomial infection rate and duration of ventilation.

Objectives: Noninvasive positive-pressure ventilation (NPPV) is increasingly used in patients with acute respiratory failure, but few data exist regarding current sedation practices during NPPV. We sought to characterize current practices and attitudes regarding sedation during NPPV., Design: Cross-sectional Web-based survey., Setting: Medical institutions., Participants: Physician members of the American College of Chest Physician's Critical Care Network (n = 2,656) and the European Respiratory Society's Assembly of Critical Care (n = 339)., Interventions: Survey., Measurements and Main Results: Of the 790 of 2,985 (27%) of physicians who responded, 15%, 6%, and 28% never used sedation, analgesia, or hand restraints any of the time for NPPV patients, respectively, and the large majority reported using these interventions in < or =25% of patients. Sedation, analgesia, and hand restraints were more commonly used by North Americans than Europeans (41% vs. 24% for sedation, 48% vs. 35% for analgesia, and 27% vs. 16% for hand restraints, all p < .01) and critical care vs. noncritical care physicians (42% vs. 24% for sedation and 50% vs. 34% for analgesia, all p < .01). A benzodiazepine alone was the most preferred (33%), followed by an opioid alone (29%). Europeans were less likely to use a benzodiazepine alone (25% vs. 39%, p < .001) but more likely to use an opioid alone (37% vs. 26%, p < .009). Sedation was usually administered as an intermittent intravenous bolus, outside of a protocol, and was assessed by nurses using clinical end points rather than a sedation scale., Conclusions: Most physicians infrequently use sedation and analgesic therapy for NPPV to treat acute respiratory failure, but practices vary widely within and between specialties and geographic regions.

Background: To assess the factors associated with reintubation in patients who had successfully passed a spontaneous breathing trial., Methods: We used logistic regression and recursive partitioning analyses of prospectively collected clinical data from adults admitted to ICUs of 37 hospitals in eight countries, who had undergone invasive mechanical ventilation for > 48 h and were deemed ready for extubation., Results: Extubation failure occurred in 121 of the 900 patients (13.4%). The logistic regression analysis identified the following associations with reintubation: rapid shallow breathing index (RSBI) [odds ratio (OR), 1.009 per unit; 95% confidence interval (CI), 1.003 to 1.015]; positive fluid balance (OR, 1.70; 95% CI, 1.15 to 2.53); and pneumonia as the reason for initiating mechanical ventilation (OR, 1.77; 95% CI, 1.10 to 2.84). The recursive partitioning analysis allowed the separation of patients into different risk groups for extubation failure: (1) RSBI of > 57 breaths/L/min and positive fluid balance (OR, 3.0; 95% CI, 1.8 to 4.8); (2) RSBI of < 57 breaths/L/min and pneumonia as reason for mechanical ventilation (OR, 2.0; 95% CI, 1.1 to 3.6); (3) RSBI of > 57 breaths/L/min and negative fluid balance (OR, 1.4; 95% CI, 0.8 to 2.5); and (4) RSBI of < 57 breaths/L/min (OR, 1 [reference value])., Conclusions: Among routinely measured clinical variables, RSBI, positive fluid balance 24 h prior to extubation, and pneumonia at the initiation of ventilation were the best predictors of extubation failure. However, the combined predictive ability of these variables was weak.

Introduction: Hypercapnic coma secondary to acute respiratory failure (ARF) is considered to be a contraindication to the use of treatment with noninvasive positive-pressure ventilation (NPPV). However, intubation exposes these patients to the risk of complications such as nosocomial pneumonia, sepsis, and even death., Patients and Methods: We performed a prospective, open, noncontrolled study to assess the outcomes of NPPV therapy in patients with a Glasgow coma scale (GCS) score of 8 responded to therapy (70%; p = 0.04). A total of 25 coma patients died in the hospital (26.3%), and 287 noncoma patients died in the hospital (33.2%; p = 0.17). The variables related to the success of NPPV therapy were GCS score 1 h posttherapy (odds ratio [OR], 2.32; 95% confidence interval [CI], 1.53 to 3.53) and higher levels of multiorgan dysfunction, as measured by the maximum sequential organ failure assessment index score reached during NPPV therapy (OR, 0.72; 95% CI, 0.55 to 0.92)., Conclusions: We concluded that selected patients with hypercapnic coma secondary to ARF can be treated as successfully with NPPV as awake patients with ARF.

Context: The results of studies on noninvasive positive pressure ventilation (NPPV) for acute hypoxemic respiratory failure unrelated to cardiogenic pulmonary edema have been inconsistent., Objective: 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., Data Source: 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., Study Selection: 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., Data Extraction: In duplicate and independently, we abstracted data to evaluate methodological quality and results., Data Synthesis: 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., Conclusion: 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.

Objective: To determine whether diagnosis and bedside observations predict outcomes of patients who have declined intubation but accept noninvasive positive pressure ventilation (NPPV) to treat their respiratory failure., Design: Prospective multiple-center cohort trial., Setting: Two teaching hospitals and two community-based hospitals in southeastern New England from January through October 1999., Patients: All patients receiving NPPV for acute respiratory failure were screened and enrolled if they had a written do-not-intubate (DNI) order., Interventions: Patients were begun on NPPV with mean inspiratory and expiratory pressures of 13.4 +/- 0.3 and 5.0 +/- 1 cm H2O, respectively. Respiratory therapists recorded demographic information, blood gases, and ventilator type and settings, and they made bedside assessments of cough strength, presence of airway secretions, awake state, and agitation. Patients were followed until discharge for duration of NPPV, survival status, and disposition., Measurements and Main Results: Of 1,211 screened patients, 114 had a DNI status and were enrolled into the study. Of these, 49 (43%) survived to discharge. Age, gender, location in a community vs. teaching hospital, and initial pH and PaO2 did not affect survival, but a higher baseline PaCO2 was associated with a favorable odds ratios for survival to discharge. Diagnosis was an important determinant of survival, with congestive heart failure patients having significantly better survival rates than those with chronic obstructive pulmonary disease, cancer, pneumonia, or other diagnoses. A stronger cough and being awake were also associated with increased probability of survival., Conclusion: Patients with respiratory failure and a DNI status have a high overall mortality rate when treated with NPPV, but those with diagnoses such as congestive heart failure or chronic obstructive pulmonary disease, who have a strong cough, or who are awake have better prognoses. These data should be useful when counseling DNI patients and their families on use of NPPV.

Background: The need for reintubation after extubation and discontinuation of mechanical ventilation is not uncommon and is associated with increased mortality. Noninvasive positive-pressure ventilation has been suggested as a promising therapy for patients with respiratory failure after extubation, but a single-center, randomized trial recently found no benefit. We conducted a multicenter, randomized trial to evaluate the effect of noninvasive positive-pressure ventilation on mortality in this clinical setting., Methods: Patients in 37 centers in eight countries who were electively extubated after at least 48 hours of mechanical ventilation and who had respiratory failure within the subsequent 48 hours were randomly assigned to either noninvasive positive-pressure ventilation by face mask or standard medical therapy., Results: A total of 221 patients with similar baseline characteristics had been randomly assigned to either noninvasive ventilation (114 patients) or standard medical therapy (107 patients) when the trial was stopped early, after an interim analysis. There was no difference between the noninvasive-ventilation group and the standard-therapy group in the need for reintubation (rate of reintubation, 48 percent in both groups; relative risk in the noninvasive-ventilation group, 0.99; 95 percent confidence interval, 0.76 to 1.30). The rate of death in the intensive care unit was higher in the noninvasive-ventilation group than in the standard-therapy group (25 percent vs. 14 percent; relative risk, 1.78; 95 percent confidence interval, 1.03 to 3.20; P=0.048), and the median time from respiratory failure to reintubation was longer in the noninvasive-ventilation group (12 hours vs. 2 hours 30 minutes, P=0.02)., Conclusions: Noninvasive positive-pressure ventilation does not prevent the need for reintubation or reduce mortality in unselected patients who have respiratory failure after extubation., (Copyright 2004 Massachusetts Medical Society)

Chronic neuromuscular diseases may affect all major respiratory muscles groups including inspiratory, expiratory, and bulbar, and respiratory complications are the major cause of morbidity and mortality. Untreated, many of these diseases lead inexorably to hypercapnic respiratory failure, precipitated in some cases by chronic aspiration and secretion retention or pneumonia, related to impairment of cough and swallowing mechanisms. Many measures are helpful including inhibition of salivation, cough-assist techniques, devices to enhance communication, and physical therapy. In addition, ventilatory assistance is an important part of disease management for patients with advanced neuromuscular disease. Because of its comfort, convenience, and portability advantages, noninvasive positive pressure ventilation (NPPV) has become the modality of first choice for most patients. Patients to receive NPPV should be selected using consensus guidelines, and initiation should be gradual to maximize the chances for success. Attention should be paid to individual preferences for interfaces and early identification of cough impairment that necessitates the use of cough-assist devices. For patients considered unsuitable for noninvasive ventilation, invasive mechanical ventilation should be considered, but only after a frank but compassionate discussion between the patient, family, physician, and other caregivers.

Noninvasive positive-pressure ventilation (NPPV) should be considered a standard of care to treat COPD exacerbations in selected patients, because NPPV markedly reduces the need for intubation and improves outcomes, including lowering complication and mortality rates and shortening hospital stay. Weaker evidence indicates that NPPV is beneficial for COPD patients suffering respiratory failure precipitated by superimposed pneumonia or postoperative complications, to allow earlier extubation, to avoid re-intubation in patients who fail extubation, or to assist do-not-intubate patients. NPPV patient-selection guidelines help to identify patients who need ventilatory assistance and exclude patients who are too ill to safely use NPPV. Predictors of success with NPPV for COPD exacerbations have been identified and include patient cooperativeness, ability to protect the airway, acuteness of illness not too severe, and a good initial response (within first 1-2 h of NPPV). In applying NPPV, the clinician must pay attention to patient comfort, mask fit and air leak, patient-ventilator synchrony, sternocleidomastoid muscle activity, vital signs, hours of NPPV use, problems with patient adaptation to NPPV (eg, nasal congestion, dryness, gastric insufflation, conjunctival irritation, inability to sleep), symptoms (eg, dyspnea, fatigue, morning headache, hypersomnolence), and gas exchange while awake and asleep. For severe stable COPD, preliminary evidence suggests that NPPV might improve daytime and nocturnal gas exchange, increase sleep duration, improve quality of life, and possibly reduce the need for hospitalization, but further study is needed. There is consensus, but without strong supportive evidence, that COPD patients who have substantial daytime hypercapnia and superimposed nocturnal hypoventilation are the most likely to benefit from NPPV. Adherence to NPPV is problematic among patients with severe stable COPD.

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.

Background: Over the past decade, noninvasive positive-pressure ventilation (NPPV) in the setting of acute exacerbations of chronic obstructive pulmonary disease (COPD) has increased in popularity. Although several trials have been published on the relative effectiveness of this treatment, apparent inconsistencies in study results remain., Purpose: To assess the effect of NPPV on rate of endotracheal intubation, length of hospital stay, and in-hospital mortality rate in patients with an acute exacerbation of COPD and to determine the effect of exacerbation severity on these outcomes., Data Sources: MEDLINE (1966 to 2002) and EMBASE (1990 to 2002). Additional data sources included the Cochrane Library, personal files, abstract proceedings, reference lists of selected articles, and expert contact. There were no language restrictions., Study Selection: The researchers selected randomized, controlled trials that 1) examined patients with acute exacerbation of COPD; 2) compared noninvasive ventilation and standard therapy with standard therapy alone; and 3) included need for endotracheal intubation, length of hospital stay, or hospital survival as an outcome., Data Extraction: Methodologic quality and results were abstracted independently and in duplicate., Data Synthesis: The addition of NPPV to standard care in patients with an acute exacerbation of COPD decreased the rate of endotracheal intubation (risk reduction, 28% [95% CI, 15% to 40%]), length of hospital stay (absolute reduction, 4.57 days [CI, 2.30 to 6.83 days]), and in-hospital mortality rate (risk reduction, 10% [CI, 5% to 15%]). However, subgroup analysis showed that these beneficial effects occurred only in patients with severe exacerbations, not in those with milder exacerbations., Conclusions: Patients with severe exacerbations of COPD benefit from the addition of NPPV to standard therapy. However, NPPV has not been shown to benefit hospitalized patients with milder COPD exacerbations.

Objective: To compare the ease and efficacy of two commonly used methods for choosing optimal positive end-expiratory pressure (PEEP) in patients with acute respiratory distress syndrome: a static pressure-volume curve to determine the lower inflection point (P(flex)) and the "best PEEP" (PEEP(best)) as determined by the maximal compliance curve., Design: Prospective study., Setting: Medical and respiratory intensive care units of university-associated tertiary care hospital., Patients: Twenty-eight patients on mechanical ventilation with acute respiratory distress syndrome., Interventions: A critical care attending physician or fellow and an experienced respiratory therapist attempted to obtain both static pressure-volume curves and maximal compliance curves on 28 patients with acute respiratory distress syndrome by using established methods that were practical to everyday use. The curves then were used to determine both P(flex) and PEEP(best), and the results were compared., Measurement and Main Results: Our results showed at least one value for optimal PEEP was obtained in 26 of 28 patients (93%). P(flex) was determined in 19 (68%), a PEEP(best) in 24 (86%), and both values in 17 (61%). In patients who had both P(flex) and PEEP(best) determined, there was a close concordance (+/-3 cm H2O) in 60%. When the values of P(flex) and PEEP(best) were interpreted by two additional investigators, there was unanimous agreement on the P(flex) (+/-3) only 64% of the time. There was agreement on the value of PEEP(best) 93% of the time., Conclusions: Our data show that optimal PEEP, as determined by a pressure-volume curve and a maximal compliance curve, are sometimes unobtainable by practical means but, when obtained, often correspond. A maximal compliance is more often identified, has less interobserver variability, and poses less risk to the patient. We conclude that determining optimal PEEP by maximal static compliance may be easier to measure and more frequently obtained at the bedside than by using a static pressure-volume curve.

Leak compensating abilities of six different positive pressure ventilators commonly used to deliver noninvasive positive pressure ventilation, including the bilevel positive airway pressure (BiPAP) S/T-D and Quantum (Respironics Inc, Murrysville, PA, USA), 335 and O'NYX (Mallinckrodt Inc, St Louis, MO, USA), PLV 102 (Respironics), and Siemens Servo 900C (Siemens Inc, Danvers, MA, USA). Using a test lung model, compensatory capabilities of the ventilators were tested for smaller and larger leaks using the assist/control or timed modes. Back-up rate was 20 min(-1), inspiratory pressure was 18 cmH2O, and expiratory pressure was 5 cmH2O. It was found that even in the absence of air leaking, delivered tidal volume differed substantially between the ventilators during use of pressure-targeted modes, depending on inspiratory flows, inaccuracies in set versus delivered pressures, and inspiratory duration. Also during pressure-targeted ventilation, increasing the tI/ttot up to, but not beyond, 0.5 improved compensation by lengthening inspiratory duration, whereas use of a sensitive flow trigger setting tended to cause autocycling during leaking, interfering with compensation. Leaking interfered with cycling of the BiPAP S/T, inverting the I:E ratio, shortening expiratory time, and reducing delivered tidal volume. Volume-targeted modes achieved limited compensation for small air leaks, but compensated poorly for large leaks. To conclude, leak-compensating capabilities differ markedly between ventilators but pressure-targeted ventilators are preferred for noninvasive positive pressure ventilation in patients with substantial air leaking. Adequate inspiratory flows and durations should be used, triggering sensitivity should be adjusted to prevent autocycling, and a mechanism should be available to limit inspiratory time and avoid I:E ratio inversion.

Objective: To evaluate whether bilevel positive airway pressure, by actively assisting inhalation, more rapidly improves ventilation, acidemia, and dyspnea than continuous positive airway pressure (CPAP) in patients with acute pulmonary edema., Design: Randomized, controlled, double-blind trial., Setting: Emergency department in a university hospital., Patients: Twenty-seven patients, presenting with acute pulmonary edema, characterized by dyspnea, tachypnea, tachycardia, accessory muscle use, bilateral rales, and typical findings of congestion on a chest radiograph., Interventions: In addition to standard therapy, 13 patients were randomized to receive nasal CPAP (10 cm H2O), and 14 patients were randomized to receive nasal bilevel positive airway pressure (inspiratory and expiratory positive airway pressures of 15 and 5 cm H2O, respectively) in the spontaneous/timed mode that combines patient flow-triggering and backup time-triggering., Measurements and Main Results: After 30 mins, significant reductions in breathing frequency (32 +/- 4 to 26 +/- 5 breaths/min), heart rate (110 +/- 21 to 97 +/- 20 beats/min), blood pressure (mean 117 +/- 28 to 92 +/- 18 mm Hg), and Paco2 (56 +/- 15 to 43 +/- 9 torr [7.5 +/- 2 to 5.7 +/- 1.2 kPa]) were observed in the bilevel positive airway pressure group, as were significant improvements in arterial pH and dyspnea scores (p < .05 for all of these parameters). Only breathing frequency improved significantly in the CPAP group (32 +/- 4 to 28 +/- 5 breaths/min, p < .05). At 30 mins; the bilevel positive airway pressure group had greater reductions in Paco2 (p = .057), systolic blood pressure (p = .005), and mean arterial pressure (p = .03) than the CPAP group. The myocardial infarction rate was higher in the bilevel positive airway pressure group (71%) compared with both the CPAP group (31%) and historically matched controls (38%) (p = .05). Duration of ventilator use, intensive care unit and hospital stays, and intubation and mortality rates were similar between the two groups., Conclusions: Bilevel positive airway pressure improves ventilation and vital signs more rapidly than CPAP in patients with acute pulmonary edema. The higher rate of myocardial infarctions associated with the use of bilevel positive airway pressure highlights the need for further studies to clarify its effects on hemodynamics and infarction rates, and to determine optimal pressure settings.

Recent studies suggest that noninvasive positive pressure ventilation (NPPV) administered by nasal or oronasal mask avoids the need for endotracheal intubation, rapidly improves vital signs, gas exchange, and sense of dyspnea, and may reduce mortality in selected patients with acute respiratory failure, but few controlled trials have been done. The present study used a randomized prospective design to evaluate the possible benefits of NPPV plus standard therapy versus standard therapy alone in patients with acute respiratory failure. Patients to receive NPPV were comfortably fitted with a standard nasal mask connected to a BiPAP ventilatory assist device (Respironics, Inc., Murrysville, PA) in the patient flow-triggered/time-triggered (S/T) mode, and standard therapy consisted of all other treatments deemed necessary by the primary physician, including endotracheal intubation. The need for intubation was reduced from 73% in the standard therapy group (11 of 15 patients) to 31% in the NPPV group (5 of 16 patients, p < 0.05). Among chronic obstructive pulmonary disease (COPD) patients, the reduction was even more striking, with 8 of 12 (67%) control patients requiring intubation compared with 1 of 11 (9%) NPPV patients (p < 0.05). Heart and respiratory rates were significantly lower in the NPPV group than in control patients within 1 h, and PaO2 was significantly improved in the NPPV group for the first 6 h. Dyspnea scores and maximal inspiratory pressures were better in the NPPV than in control patients at 6 h, and nurses and therapists spent similar amounts of time at the bedside for both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Purpose: To review the clinical use of noninvasive positive pressure ventilation, including its efficacy with acute and chronic forms of respiratory failure, its mechanism of action, and its implementation., Data Sources: Studies were identified through a MEDLINE search using the key words respiratory failure and mechanical ventilation and through a manual review of reference lists of published articles., Study Selection: All original studies relating to the use of noninvasive positive pressure ventilation in respiratory failure were included. Because of the paucity of controlled trials, cohort studies were not excluded., Data Extraction: Study design, numbers and diagnoses of patients, ventilator modes, and success and complication rates were extracted and compiled., Results: For acute respiratory failure, studies report improved gas exchange and avoidance of intubation in 60% to 80% of patients with chronic obstructive pulmonary disease, restrictive thoracic disease, congestive heart failure, pneumonia, or postoperative extubation failure. However, the patients were highly selected, and relatively few studies have been published, only one of which was a randomized controlled trial. For chronic respiratory failure due to restrictive thoracic disease, all studies report improved gas exchange and symptoms of hypoventilation after prolonged nocturnal use, although no study was controlled. Some cohort studies of patients with severe chronic obstructive pulmonary disease yielded favorable results, but longer-term, randomized, controlled studies showed minimal, if any, benefit., Conclusion: Noninvasive positive pressure ventilation is effective in the treatment of chronic respiratory failure due to restrictive thoracic diseases. The routine use of such treatment for chronic respiratory failure due to chronic obstructive pulmonary disease and for acute respiratory failure needs to be studied in randomized controlled trials in better-defined patient subsets.

We tested the efficacy of nocturnal nasal ventilation (NNV) using the BIPAP ventilator in patients with restrictive thoracic diseases by withdrawing them from NNV for an average of 1 wk. One male and five female patients were enrolled in the study; four with restrictive chest wall diseases, and two with muscular dystrophies. All patients had chronic CO2 retention (PaCO2 greater than 50 mm Hg) and had been improved by using NNV for at least 2 months before the study. Four patients were switched to the BIPAP ventilator from standard portable volume ventilators at least 1 month prior to the study without changes in gas exchange or symptoms. After withdrawal of NNV, patients had no deterioration in daytime vital signs, pulmonary functions, maximal inspiratory or expiratory pressures, or arterial blood gases compared with measures made immediately before withdrawal and 1 wk after resumption. However, patients had more dyspnea at rest, increased daytime somnolence, more morning headaches, less daytime energy, and felt less rested in the morning during withdrawal of NNV. Furthermore, nocturnal monitoring demonstrated greater tachycardia, tachypnea, oxygen desaturation, and hypoventilation during withdrawal of NNV. We conclude that NNV administered by the BIPAP ventilator is effective in ameliorating nocturnal hypoventilation and daytime symptoms in patients with chronic CO2 retention caused by severe restrictive thoracic diseases. These data also suggest that the efficacy of NNV may depend more on amelioration of nocturnal hypoventilation than on resting of ventilatory muscles.

Intermittent positive pressure ventilation administered nocturnally via a nasal mask has been associated with improvements in pulmonary function and symptoms in patients with restrictive ventilatory disorders. We hypothesized that nocturnal nasal ventilation (NNV) would bring about similar improvements in patients with severe chronic obstructive pulmonary disease (COPD). The study used a randomized, crossover design, with subjects undergoing NNV or "standard care" for sequential 3-month periods. Of 23 patients with obstructive lung disease and a FEV1 less than 1 L who were initially enrolled, 4 were excluded because of obstructive sleep apnea prior to randomization. Among the remaining 19 patients, 7 withdrew because of intolerance of the nose mask, 5 were withdrawn because of intercurrent illnesses, and 7 completed both arms of the protocol. These latter 7 patients used the ventilator for an average of 6.7 h/night, and 3 of the 7 had partial relief of dyspnea during ventilator use. However, in comparison with studies performed upon initiation or after the standard care arm of the study, studies performed after 3 months of NNV revealed no improvements in pulmonary function, respiratory muscle strength, gas exchange, exercise endurance, sleep efficiency, quality or oxygenation, or dyspnea ratings. The only improvements observed were in neuropsychological function, possibly related to a placebo effect or another unknown mechanism. Despite the small sample size, our study indicates that NNV is not well tolerated by and brings about minimal improvements in stable outpatients with severe COPD.

We followed eight patients with Duchenne-type muscular dystrophy for an average of 39 months after initiation of noninvasive intermittent ventilatory assistance using body ventilators. After one to three months of nocturnal use averaging 8 h, mean daytime PaCO2 fell from 63 +/- 2 to 45 +/- 3 mm Hg. At late follow-up, PaCO2 remained stable at 47 +/- 4 mm Hg, but vital capacity fell 33 percent compared with the initial value and the average duration of ventilator use had increased to 18 +/- 2 h daily. Three patients died and five survived; two continued using negative pressure ventilators and three had tracheostomies placed for administration of positive pressure ventilation. We conclude that noninvasive intermittent ventilatory assistance effectively reverses hypoventilation and symptoms in patients with late-stage Duchenne muscular dystrophy, but pulmonary function continues to deteriorate necessitating longer periods of ventilation, and often tracheostomy, within a few years.

Interest has been increasing in providing ventilatory support in the home for patients with chronic respiratory failure, mainly with the use of positive pressure ventilation via a chronic tracheostomy. However, body ventilators that assist ventilation by applying intermittent negative or positive pressure to the thorax, abdomen, or airway without requiring an artificial airway, can offer distinct advantages for selected patients over systems requiring a permanent airway. These ventilators include the iron lung, portable lung (Portalung), pneumowrap, chest cuirass, pneumobelt, rocking bed, and positive pressure provided via a face or nose mask. They have successfully stabilized or reversed chronic hypercarbia when used intermittently in patients with slowly progressive chronic respiratory failure due to certain neuromuscular diseases and kyphoscoliosis. How they achieve this stabilization has not been clarified, but reversal of chronic respiratory muscle fatigue following periodic rest probably contributes. These ventilators are generally less effective than positive pressure ventilation through a tracheostomy and should be reserved for patients with relatively stable chronic respiratory failure and intact upper airways. However, they have the advantages of simpler operation and less expense, and they allow maintenance of a normal airway.