Predictors of failure of noninvasive positive pressure ventilation in patients with acute hypoxemic respiratory failure: a multi-center study

Predictive factors for the outcome of noninvasive ventilation in pediatric acute respiratory failure

OBJECTIVES

To identify success and failure prognostic signs of noninvasive ventilation in pediatric acute respiratory failure. Noninvasive ventilation constitutes an alternative treatment for pediatric acute respiratory failure. However, tracheal intubation should not be delayed when considered necessary.

DESIGN

Prospective, noncontrolled, clinical study.

SETTING

Pediatric intensive care unit in a university hospital.

PATIENTS

Children (age range, 1 month-16 yrs) with moderate-to-severe acute respiratory failure who received noninvasive ventilation during a 4-year period. Failure was defined as the need for tracheal intubation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Nine (19.1%) of 47 patients needed tracheal intubation between the third and 87th hour after the start of treatment (33.6 ± 29.6 hrs). Failure was associated with the younger age group (4 ± 3.3 yrs vs. 7.7 ± 5 yrs, p < .04), acute respiratory distress syndrome (failure/acute respiratory distress syndrome: 5 of 10 vs. failure/non acute respiratory distress syndrome: 4 of 37, p = .013), and worsening radiographic images taken at 24 hrs and/or 48-72 hrs (p = .001 and p < .001, respectively). A significant reduction in heart rate was observed between the second and fourth hour after starting noninvasive ventilation (130 ± 25.8 bpm vs. 116 ± 27.7 bpm, p < .001) and Pco2 (54.1 ± 19.5 torr vs. 48.6 ± 14.3 torr; 7.21 ± 2.6 vs. 6.48 ± 1.91 kPa, p < .007) in the success group. The failure group had a higher rate of breathing assistance, both initial and maximal. In the multivariant analysis, only maximum mean airway pressure and Fio2 formed part of the success/failure discriminant function with a cutoff point of 11.5 and 0.57, respectively.

CONCLUSIONS

Modifications in a patient's respiratory assistance were made depending on the clinical, blood gas, and radiologic evolution of the patient. Mean airway pressure and Fio2 values of >11.5 and 0.6, respectively, predict failure and possibly set the limit above the patient's risk of delayed intubation increases.

Pulmonary contusion: an update on recent advances in clinical management

Pulmonary contusion is a common finding after blunt chest trauma. The physiologic consequences of alveolar hemorrhage and pulmonary parenchymal destruction typically manifest themselves within hours of injury and usually resolve within approximately 7 days. Clinical symptoms, including respiratory distress with hypoxemia and hypercarbia, peak at about 72 h after injury. The timely diagnosis of pulmonary contusion requires a high degree of clinical suspicion when a patient presents with trauma caused by an appropriate mechanism of injury. The clinical diagnosis of acute parenchymal lung injury is usually confirmed by thoracic computed tomography, which is both highly sensitive in identifying pulmonary contusion and highly predictive of the need for subsequent mechanical ventilation. Management of pulmonary contusion is primarily supportive. Associated complications such as pneumonia, acute respiratory distress syndrome, and long-term pulmonary disability, however, are frequent sequelae of these injuries.

Oxygen saturation/fraction of inspired oxygen ratio is a simple predictor of noninvasive positive pressure ventilation failure in critically ill patients

PURPOSE

Noninvasive positive pressure ventilation (NPPV) can improve outcomes of critically ill patients. Early and simple predictors of NPPV outcome could improve clinical management of patients with respiratory failure.

MATERIALS AND METHODS

A prospective observational study was conducted in a medical intensive care unit of a tertiary medical center. Patients requiring NPPV were included and followed. Clinical data including respiratory mechanics at the time of NPPV initiation, and clinical outcomes were recorded. Data were analyzed to identify variables that distinguished NPPV success or failure.

RESULTS

A total of 133 patients were included in the study. Noninvasive positive pressure ventilation success rate was 41%. Patients diagnosed with malignancy had only 29% NPPV success rate. Among patients without malignancy, higher oxygen saturation, oxygen saturation/fraction of inspired oxygen (SF) ratios, and SF/minute ventilation ratios were associated with NPPV success. Receiver operating characteristic curve analyses identify SF ratio less than 98.5 to be a specific (89% specificity, P = .013) predictor of NPPV failure. Furthermore, for patients requiring at least 24 hours of NPPV support, tidal volume/predicted body weight ratio negatively correlated with respiratory improvement.

CONCLUSIONS

For patients without malignancy, SF ratios at the time of NPPV initiation discriminated NPPV success and failure, and could be used to help guide the management of critically ill patients who require ventilatory support.

Noninvasive positive pressure ventilation for patients with acute hypoxemic respiratory failure?

The re-emergence of noninvasive positive pressure ventilation (NIV) represents perhaps the single greatest advance in mechanical ventilation over the last 20 years. Clear benefit has been demonstrated for patients with respiratory failure in the setting of acute exacerbations of chronic obstructive pulmonary disease and cardiogenic pulmonary edema. While there are advocates for the use of NIV in patients presenting with acute hypoxemic respiratory failure not due to cardiogenic pulmonary edema, benefit for these patients is less clear. This article reviews briefly the heterogeneity of hypoxemic respiratory failure and looks at the current evidence to support NIV in this setting in some depth. Presently, there is little evidence to support the use of NIV for patients presenting with hypoxemic respiratory failure who fulfill the American and European Consensus Conference definition of acute lung injury or acute respiratory distress syndrome, other than in patients with high risk for death if endotracheally intubated (immunocompromised patients, postlung resection acute respiratory distress syndrome). As there are reasonable rationales for both benefit and harm, there is a need for a large, multicenter, randomized, controlled trial to clarify whether NIV offers benefit in terms of a reduced need for endotracheal intubation, length of stay and hospital mortality.

Factors associated with noninvasive ventilation failure in postoperative acute respiratory insufficiency: an observational study

BACKGROUND AND OBJECTIVE

Few data are available on the efficacy of noninvasive ventilation (NIV) in postoperative patients with acute respiratory failure (ARF).

METHODS

Seventy-two patients coming from the surgical wards with postoperative ARF were retrospectively evaluated. The major characteristics of patients who were intubated were compared with the characteristics of those who were not after a trial of NIV. Predictive factors for failure of NIV were analysed.

RESULTS

Out of 72 patients with ARF after surgery who were treated with NIV, 42 avoided intubation (58%). On a univariate analysis, a decrease in the paO2/FiO2 ratio after 1 h of NIV (223 +/- 84 to 160 +/- 68 mmHg, P < 0.05) was associated with NIV failure and need for tracheal intubation because of nosocomial pneumonia and an increased simplified acute physiology score (SAPS) 2. In a multivariate analysis, nosocomial pneumonia [odds ratio (OR) 4.189; 95% confidence interval (CI) 1.383-12.687] and SAPS 2 higher than 35 (OR 4.969; 95% CI 1.627-15.172) were independent predictive factors of NIV failure. NIV success was associated with a reduced ICU stay (16.8 vs. 26.1 days, P < 0.001).

CONCLUSION

NIV could be considered in postoperative patients who presented with ARF. Nosocomial pneumonia is predictive of NIV failure.

Infection control in mass respiratory failure: preparing to respond to H1N1

The first hints of a global public health crisis emerged with the identification of a new strain of H1N1 influenza A in March and April 2009 in Mexico City. By June 11, the World Health Organization had declared the outbreak of 2009 H1N1 a global pandemic. Now, with the continued growing presence of 2009 H1N1 on the global scene, much attention has been focused on the key role of personal protective equipment in healthcare infection control. Much less emphasis has been placed on specific interventions that may minimize the increased infectious risk commonly associated with critical care delivery. Given the frequency of high-risk respiratory procedures such as intubation and delivery of aerosolized medications in the intensive care unit, the delivery of critical care presents unique infection control challenges and unique opportunities to augment usual infection control practice with specific source-control efforts. Here, we summarize data regarding risks to critical care healthcare workers from previous respiratory virus outbreaks, discuss findings from the early 2009 H1N1 experience that suggest reasons for increased concern for those delivering critical care, and review best available evidence regarding strategies for source control in respiratory and critical care delivery.

Early onset pneumonia in severe chest trauma: a risk factor analysis

BACKGROUND

The development of an early-onset pneumonia (EOP), occurring within the first 72 hours after admission, represents a critical event in severe thoracic trauma population. The aim of this study was to determine risk factors associated with the occurrence of this complication in this specific population.

METHODS

A retrospective review of a prospective implemented trauma registry was conducted during a 4-year period in a Level I trauma center. Over the study period, 223 severely injured patients were admitted with severe thoracic trauma (Injury Severity Score >16 and Thorax Abbreviated Injury Score >2). Multiple logistic regression analysis was used to determine the independent predictors of EOP based on the clinical characteristics and the initial management both in the field and after admission in the trauma center.

RESULTS

Independent predictors of EOP were the necessity of intubation and mechanical ventilation in the field (adjusted odds ratio [OR]: 11.8; 95% confidence interval [CI]: 4.3-32.7), a history of aspiration (OR: 28.6; 95% CI: 4.0-203.5), the presence of pulmonary contusion (OR: 7.0; 95% CI: 2.0-23.9), and the occurrence of a hemothorax (OR: 3.2; 95% CI: 1.4-7.6).

CONCLUSION

These results emphasize the influence of prehospital and early factors in the further occurrence of EOP, which allows the development of early and specific clinical management to prevent it.

Noninvasive and invasive ventilation in acute respiratory failure associated with bronchiectasis

PURPOSE

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

METHODS

Retrospective review of bronchiectatic patients on NIV (n = 31) or IMV (n = 26) for ARF over 8 years in a medical intensive care unit (ICU) experienced in NIV.

RESULTS

At baseline, the NIV group had more patients with acute exacerbations without identified precipitating factors (87.1 vs. 34.6%, p < 0.001), higher pH (mean 7.25 vs. 7.18, p = 0.008) and PaO(2)/FiO(2) ratio (mean 249.4 vs. 173.2, p = 0.02), and a trend towards a lower APACHE II score (mean 25.3 vs. 28.4, p = 0.07) than the IMV group. There was no difference in hospital mortality between the two groups (25.8 vs. 26.9%, p > 0.05). The NIV failure rate (need for intubation or death in the ICU) was 32.3%. Using logistic regression, the APACHE II score was the only predictor of hospital mortality (OR 1.19 per point), and the PaO(2)/FiO(2) ratio was the only predictor of NIV failure (OR 1.02 per mmHg decrease).

CONCLUSIONS

The hospital mortality of patients with bronchiectasis and ARF approximates 25% and is predicted by the APACHE II score. When selectively applied, NIV fails in one-third of the patients, and this is predicted by hypoxemia. Our findings call for randomised controlled trials to compare NIV versus IMV in such patients.

Extubation of patients with neuromuscular weakness: a new management paradigm

BACKGROUND

Successful extubation conventionally necessitates the passing of spontaneous breathing trials (SBTs) and ventilator weaning parameters. We report successful extubation of patients with neuromuscular disease (NMD) and weakness who could not pass them.

METHODS

NMD-specific extubation criteria and a new extubation protocol were developed. Data were collected on 157 consecutive "unweanable" patients, including 83 transferred from other hospitals who refused tracheostomies. They could not pass the SBTs before or after extubation. Once the pulse oxyhemoglobin saturation (Spo(2)) was maintained at > or = 95% in ambient air, patients were extubated to full noninvasive mechanical ventilation (NIV) support and aggressive mechanically assisted coughing (MAC). Rather than oxygen, NIV and MAC were used to maintain or return the Spo(2) to > or = 95%. Extubation success was defined as not requiring reintubation during the hospitalization and was considered as a function of diagnosis, preintubation NIV experience, and vital capacity and assisted cough peak flows (CPF) at extubation.

RESULTS

Before hospitalization 96 (61%) patients had no experience with NIV, 41 (26%) used it < 24 h per day, and 20 (13%) were continuously NIV dependent. The first-attempt protocol extubation success rate was 95% (149 patients). All 98 extubation attempts on patients with assisted CPF > or = 160 L/m were successful. The dependence on continuous NIV and the duration of dependence prior to intubation correlated with extubation success (P < .005). Six of eight patients who initially failed extubation succeeded on subsequent attempts, so only two with no measurable assisted CPF underwent tracheotomy.

CONCLUSIONS

Continuous volume-cycled NIV via oral interfaces and masks and MAC with oximetry feedback in ambient air can permit safe extubation of unweanable patients with NMD.

Noninvasive ventilation reduces intubation in chest trauma-related hypoxemia: a randomized clinical trial

BACKGROUND

Guidelines for noninvasive mechanical ventilation (NIMV) recommend continuous positive airway pressure in patients with thoracic trauma who remain hypoxic despite regional anesthesia. This recommendation is rated only by level C evidence because randomized controlled trials in this specific population are lacking. Our aim was to determine whether NIMV reduces intubation in severe trauma-related hypoxemia.

METHODS

This was a single-center randomized clinical trial in a nine-bed ICU of a level I trauma hospital. Inclusion criteria were patients with Pao(2)/Fio(2)<200 for >8 h while receiving oxygen by high-flow mask within the first 48 h after thoracic trauma. Patients were randomized to remain on high-flow oxygen mask or to receive NIMV. The interface was selected based on the associated injuries. Thoracic anesthesia was universally supplied unless contraindicated. The primary end point was intubation; secondary end points included length of hospital stay and survival. Statistical analysis was based on multivariate analysis.

RESULTS

After 25 patients were enrolled in each group, the trial was prematurely stopped for efficacy because the intubation rate was much higher in controls than in NIMV patients (10 [40%] vs 3 [12%], P = .02). Multivariate analysis adjusted for age, gender, chronic heart failure, and Acute Physiology and Chronic Health Evaluation II at admission revealed NIMV as the only variable independently related to intubation (odds ratio, 0.12; 95% CI, 0.02-0.61; P = .01). Length of hospital stay was shorter in NIMV patients (14 vs 21 days P = .001), but no differences were observed in survival or other secondary end points.

CONCLUSION

NIMV reduced intubation compared with oxygen therapy in severe thoracic trauma-related hypoxemia.

Non-invasive ventilation in acute respiratory failure

Non-invasive mechanical ventilation has been increasingly used to avoid or serve as an alternative to intubation. Compared with medical therapy, and in some instances with invasive mechanical ventilation, it improves survival and reduces complications in selected patients with acute respiratory failure. The main indications are exacerbation of chronic obstructive pulmonary disease, cardiogenic pulmonary oedema, pulmonary infiltrates in immunocompromised patients, and weaning of previously intubated stable patients with chronic obstructive pulmonary disease. Furthermore, this technique can be used in postoperative patients or those with neurological diseases, to palliate symptoms in terminally ill patients, or to help with bronchoscopy; however further studies are needed in these situations before it can be regarded as first-line treatment. Non-invasive ventilation implemented as an alternative to intubation should be provided in an intensive care or high-dependency unit. When used to prevent intubation in otherwise stable patients it can be safely administered in an adequately staffed and monitored ward.

Patient outcomes after noninvasive mechanical ventilation at a high dependency unit of an emergency department

OBJECTIVE

To describe the outcome of patients after noninvasive ventilation in a high dependency unit (HDU) of an emergency department (ED). Secondary aims were to define the role of intensive care consultation and to identify variables associated with mortality.

METHODS

Observational, prospective 6-month study.

RESULTS

Two hundred and nine cases were analysed. Thirty-four patients were initially rejected by the intensive care unit (ICU). Physicians in the ED did not request ICU consultation in the remaining 175 (83%) because of 'belief of improvable medical condition in the ED in patients without therapeutic limits' in 93 (group 1) and to 'preset therapeutic limits' or 'comfort measures only' in 82 (groups 2 and 3). Ten out of these 175 were subsequently admitted to the ICU. The global in-hospital mortality rate was 22% (3.3% in the high dependency unit), but only 10% in group 1. Place of referral for ventilation (P<0.001), absence of subsequent ventilation on the general ward (P<0.001), group of assignation (P=0.004), intensive care initial rejection (P=0.022), no previous home ventilation (P=0.028), older age (P=0.03) and longer duration on ventilation (P=0.047) were significantly associated with mortality. In the multivariate regression model, ventilating patients from general wards (odds ratio=7.1; 2.3-25, 95% confidence interval) and ventilation under preset limits (odds ratio=3.57; 1.42-8.98, 95% confidence interval) remained significantly associated with mortality.

CONCLUSION

Noninvasive ventilation is a relatively safe and effective treatment in the ED when performed in carefully controlled settings. ICU consultation may be securely deferred in this setting.

Review of non-invasive ventilation in the emergency department: clinical considerations and management priorities

AIMS AND OBJECTIVES

We aimed to synthesise evidence from published literature on non-invasive ventilation to inform nurses involved in the clinical management of non-invasive ventilation in the emergency department.

BACKGROUND

Non-invasive ventilation is a form of ventilatory support that does not require endotracheal intubation and is used in the early management of acute respiratory failure in emergency departments. Safe delivery of this intervention requires a skilled team, educated and experienced in appropriate patient selection, available devices and monitoring priorities.

DESIGN

Systematic review.

METHOD

A multi-database search was performed to identify works published in the English language between 1998-2008. Search terms included: non-invasive ventilation, continuous positive airway pressure and emergency department. Inclusion and exclusion criteria for the review were identified and systematically applied.

RESULTS

Terminology used to describe aspects of non-invasive ventilation is ambiguous. Two international guidelines inform the delivery of this intervention, however, much research has been undertaken since these publications. Strong evidence exists for non-invasive ventilation for patients with acute exacerbation of congestive heart failure and chronic obstructive pulmonary disease. Non-invasive ventilation may be delivered with various interfaces and modes; little evidence is available for the superiority of individual interfaces or modes.

CONCLUSIONS

Early use of non-invasive ventilation for the management of acute respiratory failure may reduce mortality and morbidity. Though international guidelines exist, specific recommendations to guide the selection of modes, settings or interfaces for various aetiologies are lacking due to the absence of empirical evidence.

RELEVANCE TO CLINICAL PRACTICE

Monitoring of non-invasive ventilation should focus on assessment of response to treatment, respiratory and haemodynamic stability, patient comfort and presence of air leaks. Complications are related to mask-fit and high air flows; serious complications are few and occur infrequently. The use of non-invasive ventilation has resource implications that must be considered to provide effective and safe management in the emergency department.

Acute respiratory failure in intensive care units. FINNALI: a prospective cohort study

OBJECTIVE

To evaluate the incidence, treatment and mortality of acute respiratory failure (ARF) in Finnish intensive care units (ICUs).

STUDY DESIGN

Prospective multicentre cohort study.

METHODS

All adult patients in 25 ICUs were screened for use of invasive or non-invasive ventilatory support during an 8-week period. Patients needing ventilatory support for more than 6 h were included and defined as ARF patients. Risk factors for ARF and details of prior chronic health status were assessed. Ventilatory and concomitant treatments were evaluated and recorded daily throughout the ICU stay. ICU and 90-day mortalities were assessed.

RESULTS

A total of 958 (39%) from the 2,473 admitted patients were treated with ventilatory support for more than 6 h. Incidence of ARF, acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) was 149.5, 10.6 and 5.0/100,000 per year, respectively. Ventilatory support was started with non-invasive interfaces in 183 of 958 (19%) patients. Ventilatory modes allowing triggering of spontaneous breaths were preferred (81%). Median tidal volume/predicted body weight was 8.7 (7.6-9.9) ml/kg and plateau pressure 19 (16-23) cmH2O. The 90-day mortality of ARF was 31%.

CONCLUSIONS

While the incidence of ARF requiring ventilatory support is higher, the incidence of ALI and ARDS seems to be lower in Finland than previously reported in other countries. Tidal volumes are higher than recommended in the concept of lung protective strategy. However, restriction of peak airway pressure was used in the majority of ARF patients.

Avoiding circulatory complications during endotracheal intubation and initiation of positive pressure ventilation

BACKGROUND

In many hospitals, emergency physicians commonly initiate invasive positive-pressure ventilation.

OBJECTIVES

To review common patient- and ventilator-related factors that can promote hemodynamic instability during and after endotracheal intubation.

DISCUSSION

Venous return is proportional to mean systemic pressure (Pms) minus right atrial pressure (Pra). Endotracheal intubation with positive-pressure ventilation often reduces Pms while always increasing Pra, so venous return inevitably decreases, resulting in hypotension in almost one-third of patients. This article reviews the pathophysiology of respiratory failure, the basic circulatory physiology associated with endotracheal intubation, and methods that may be helpful to reduce the frequency of intubation-related hypotension.

CONCLUSION

Although unproven, preventive measures taken before, during, and after endotracheal intubation are likely to minimize the frequency, magnitude, and duration of intubation-related hypotension.

Effect of noninvasive mechanical ventilation in elderly patients with hypercapnic acute-on-chronic respiratory failure and a do-not-intubate order

Noninvasive mechanical ventilation (NIMV) is effective in the treatment of patients with acute respiratory failure (ARF). It proved to reduce the need of endotracheal intubation (ETI), the incidence of ETI-associated pneumonia, and mortality compared to nonventilated patients. A particular aspect concerns the outcome of NIMV in patients referring to an emergency room (ER) for ARF, and with a do-not-intubate (DNI) status due to advanced age or critical conditions. The aim of our study is to assess the outcome of NIMV in a group of elderly patients with acute hypercapnic ARF who had a DNI status. An overall number of 62 subjects (30 males, 32 females, mean age 81 ± 4.8 years, range 79–91 years) referred to our semi-intensive respiratory department were enrolled in the study. The underlying diseases were severe chronic obstructive pulmonary disease (COPD) in 50/62 subjects, restrictive thoracic disorders in 7/62 subjects, and multiorgan failure in 5/62 subjects. Fifty-four/62 patients were successfully treated with NIMV while 2/62 did not respond to NIMV and were therefore submitted to ETI (one survived). Among NIMV-treated patients, death occurred in 6 patients after a mean of 9.9 days; the overall rate of NIMV failure was 12.9%. Negative prognostic factors for NIMV response proved to be: an older age, a low Glasgow Coma Score, a high APACHE score at admission, a high PaCO₂ after 12 hours and a low pH both after 1 and 12 hours of NIMV. We conclude that elderly patients with acute hypercapnic ARF with a DNI status can be successfully treated by NIMV.

[Impact of sophrology on non-invasive ventilation tolerance in patients with acute respiratory failure]

OBJECTIVES

Non-invasive ventilation (NIV) in patients with acute respiratory failure (ARF) is subject to a large number of failures due to discomfort of the art, the feeling of difficulty breathing and pain. The purpose of this study was to evaluate the efficiency of sophrology to improve conditions for the realization of NIV in patients with ARF.

PATIENTS AND METHODS

In this prospective randomized and controlled study, consecutive patients with ARF were included. From the very first NIV session, they received either sophrology during the first 30 min of NIV (S group), or standard care by the same nurse during 30 min (T group). The hemodynamic and ventilatory data were recorded continuously; pain, respiratory difficulty and discomfort were measured with a numeric scale at the end of the session.

RESULTS

Thirty patients were included in the study, 27 have been analysed. Each patient received an average of four sessions NIV during the protocol. There was no significant difference between the two groups in terms of improvement in gas exchange. In contrast, there was a significant difference in terms of reduction of difficulty in breathing (-76%), discomfort (-60%) and decrease the pain (-40%) in the sophrology group (p<0.001). Respiratory rate, heart rate and systolic arterial blood pressure were decrease during NIV.

CONCLUSION

Sophrology constitutes aid for the achievement of the meetings of NIV in patients' IRA.

[Non-invasive ventilation as treatment for acute respiratory insufficiency. Essentials from the new S3 guidelines]

BACKGROUND

Scientific evidence is accumulating that non-invasive ventilation (NIV) may be beneficial for different patient groups with acute respiratory insufficiency (ARI). The aim of the new S3 guidelines is to propagate evidence-based knowledge about the indications and limitations of NIV in clinical practice.

METHODS

A total of 28 experts from 12 German medical societies were involved in the process of development of the present guidelines. These experts systematically analyzed approximately 2,900 publications. Finally, the recommendations were discussed and approved in two consensus conferences.

RESULTS

In hypercapnic ARI, NIV reduces the length of stay and mortality during intensive care treatment [grade A recommendation (A)]. Patients with cardiopulmonary edema should be treated with continuous positive airway pressure (CPAP) or NIV (A). For immunocompromized patients with ARI, NIV reduces the mortality (A). In patients with postextubation respiratory failure and during weaning from mechanical ventilation, NIV reduces the risk of reintubation (A). For patients who decline to be ventilated invasively, NIV may be an acceptable alternative (B). Non-invasive ventilation can also successfully be used in pediatric patients with ARI caused by different reasons (C). In acute respiratory distress syndrome (ARDS) NIV cannot generally be recommended because the failure rate is relatively high.

CONCLUSION

Non-invasive ventilation is still not as widely implemented in clinical medicine as would be expected on the basis of the scientific literature. The aim of the present guidelines is to further propagate NIV for the treatment of ARI.

Use of noninvasive positive-pressure ventilation in the emergency department

To optimize the successful use of noninvasive positive-pressure ventilation (NPPV) in the emergency department (ED), clinicians must acquire the necessary knowledge, experience, and skill in its proper application. The purpose of this article is to provide a concise but thorough review of the current state of knowledge relating to the proper application of NPPV pertaining to its use in the ED.

Patient-ventilator asynchrony during non-invasive ventilation for acute respiratory failure: a multicenter study

OBJECTIVE

To determine the prevalence of patient-ventilator asynchrony in patients receiving non-invasive ventilation (NIV) for acute respiratory failure.

DESIGN

Prospective multicenter observation study.

SETTING

Intensive care units in three university hospitals.

METHODS

Patients consecutively admitted to ICU were included. NIV, performed with an ICU ventilator, was set by the clinician. Airway pressure, flow, and surface diaphragmatic electromyography were recorded continuously for 30 min. Asynchrony events and the asynchrony index (AI) were determined from visual inspection of the recordings and clinical observation.

RESULTS

A total of 60 patients were included, 55% of whom were hypercapnic. Auto-triggering was present in 8 (13%) patients, double triggering in 9 (15%), ineffective breaths in 8 (13%), premature cycling 7 (12%) and late cycling in 14 (23%). An AI > 10%, indicating severe asynchrony, was present in 26 patients (43%), whose median (25-75 IQR) AI was 26 (15-54%). A significant correlation was found between the magnitude of leaks and the number of ineffective breaths and severity of delayed cycling. Multivariate analysis indicated that the level of pressure support and the magnitude of leaks were weakly, albeit significantly, associated with an AI > 10%. Patient comfort scale was higher in pts with an AI < 10%.

CONCLUSION

Patient-ventilator asynchrony is common in patients receiving NIV for acute respiratory failure. Our results suggest that leaks play a major role in generating patient-ventilator asynchrony and discomfort, and point the way to further research to determine if ventilator functions designed to cope with leaks can reduce asynchrony in the clinical setting.

Predictive factors of non invasive ventilation failure in critically ill children: a prospective epidemiological study

OBJECTIVE

Identification of predictive factors for non-invasive ventilation (NIV) failure and determination of NIV characteristics.

DESIGN

Prospective observational study.

SETTING

Paediatric Intensive Care Unit in a University Hospital.

PATIENTS AND MEASUREMENTS

A total of 116 episodes were included. Clinical data collected were respiratory rate (RR), heart rate and FiO(2) before NIV began. Same data and expiratory and support pressures were collected at 1, 6, 12, 24 and 48 h. Conditions precipitating acute respiratory failure (ARF) were classified into two groups: type 1 (38 episodes) and type 2 (78 episodes). Ventilation-perfusion impairment was the main respiratory failure mechanism in type 1, and hypoventilation in type 2. Factors predicting NIV failure were determined by multivariate analysis.

RESULTS

Most common admission diagnoses were pneumonia (81.6%) in type 1 and bronchiolitis (39.7%) and asthma (42.3%) in type 2. Complications secondary to NIV were detected in 23 episodes (20.2%). NIV success rate was 84.5% (68.4% in type 1 and 92.3% in type 2). Type 1 patients showed a higher risk of NIV failure compared to type 2 (OR 11.108; CI 95%, 2.578-47.863). A higher PRISM score (OR 1.138; CI 95%, 1.022-1.267), and a lower RR decrease at 1 h and at 6 h (OR 0.926; CI 95%, 0.860-0.997 and OR 0.911; CI 95%, 0.837-0.991, respectively) were also independently associated with NIV failure.

CONCLUSIONS

NIV is a useful respiratory support technique in paediatric patients. Type 1 group classification, higher PRISM score, and lower RR decrease during NIV were independent risk factors for NIV failure.

[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.

Predictors of noninvasive ventilation failure in patients with hematologic malignancy and acute respiratory failure

OBJECTIVES

The current trend to manage critically ill hematologic patients admitted with acute respiratory failure is to perform noninvasive ventilation to avoid endotracheal intubation. However, failure of noninvasive ventilation may lead to an increased mortality.

DESIGN

Retrospective study to determine the frequency of noninvasive ventilation failure and identify its determinants.

SETTING

Medical intensive care unit in a University hospital.

PATIENTS

All consecutive patients with hematologic malignancies admitted to the intensive care unit over a 10-yr period who received noninvasive ventilation.

RESULTS

A total of 99 patients were studied. Simplified Acute Physiology Score II at admission was 49 (median, interquartile range, 39-57). Fifty-three patients (54%) failed noninvasive ventilation and required endotracheal intubation. Their PaO2/FiO2 ratio was significantly lower (175 [101-236] vs. 248 [134-337]) and their respiratory rate under noninvasive ventilation was significantly higher (32 breaths/min [30-36] vs. 28 [27-30]). Forty-seven patients (89%) who failed noninvasive ventilation required vasopressors. Hospital mortality was 79% in those who failed noninvasive ventilation, and 41% in those who succeeded. Patients who failed noninvasive ventilation had a significantly longer intensive care unit stay (13 days [8-23] vs. 5 [2-8]) and a significantly higher rate of intensive care unit-acquired infections (32% compared with 7%). Factors independently associated with noninvasive ventilation failure by multivariate analysis were respiratory rate under noninvasive ventilation, longer delay between admission and noninvasive ventilation first use, need for vasopressors or renal replacement therapy, and acute respiratory distress syndrome.

CONCLUSIONS

Failure of noninvasive ventilation occurs in half the critically ill hematologic patients and is associated with an increased mortality. Predictors of noninvasive ventilation failure might be used to guide decisions regarding intubation.

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

BACKGROUND

A single prospective randomized study found that, in selected patients with acute respiratory failure (ARF) following lung resection, noninvasive ventilation (NIV) decreases the need for endotracheal mechanical ventilation and improves clinical outcome.

METHOD

We prospectively evaluated early NIV use for ARF after lung resection during a 4-year period in the setting of a medical and a surgical ICU of a university hospital. We documented demographics, initial clinical characteristics and clinical outcomes. NIV failure was defined as the need for tracheal intubation.

RESULTS

Among 690 patients at risk of severe complications following lung resection, 113 (16.3%) experienced ARF, which was initially supported by NIV in 89 (78.7%), including 59 with hypoxemic ARF (66.3%) and 30 with hypercapnic ARF (33.7%). The overall success rate of NIV was 85.3% (76/89). In-ICU mortality was 6.7% (6/89). The mortality rate following NIV failure was 46.1%. Predictive factors of NIV failure in univariate analysis were age (P = 0.046), previous cardiac comorbidities (P = 0.0075), postoperative pneumonia (P = 0.0016), admission in the surgical ICU (P = 0.034), no initial response to NIV (P < 0.0001) and occurrence of noninfectious complications (P = 0.037). Only two independent factors were significantly associated with NIV failure in multivariate analysis: cardiac comorbidities (odds ratio, 11.5; 95% confidence interval, 1.9-68.3; P = 0.007) and no initial response to NIV (odds ratio, 117.6; 95% confidence interval, 10.6-1305.8; P = 0.0001).

CONCLUSION

This prospective survey confirms the feasibility and efficacy of NIV in ARF following lung resection.

Mortality in acute cardiogenic pulmonary edema treated with continuous positive airway pressure

OBJECTIVE

To investigate mortality in acute cardiogenic pulmonary edema (ACPE) patients treated with continuous positive airway pressure (CPAP) and to identify clinical and laboratory characteristics associated with mortality.

DESIGN

Observational, retrospective study.

SETTING

Emergency Medicine Department.

PATIENTS AND PARTICIPANTS

A total of 454 consecutive ACPE patients treated with CPAP.

MEASUREMENTS AND RESULTS

Demographics, past medical history, clinical characteristics, laboratory evaluation, in-hospital mortality data were collected. Potential predictors of in-hospital mortality that were considered of clinical relevance and immediately accessible on admission were investigated by multivariable logistic regression. ACPE-related mortality rate was 3.8% (17/452 patients) and the in-hospital mortality rate was 11.4% (50/440 patients). Significant independent predictors of increased risk of in-hospital mortality were: advanced age (P = 0.012), normal-to-low blood pressure (P < 0.001), low PaO(2)/FiO(2) ratio (P = 0.020), hypocapnia (P = 0.009) and anemia (P = 0.05).

CONCLUSIONS

Values recorded within few minutes from arrival to the hospital can predict mortality in ACPE patients treated with CPAP who has been tested, for the first time, in a real life study. This can allow physicians to quickly recognize more severe ACPE patients treated with CPAP and plan for aggressive monitoring and treatment and for deciding the better site of care.

Factors predicting successful noninvasive ventilation in acute lung injury

PURPOSE

Noninvasive ventilation (NIV) has been successfully used to treat various forms of acute respiratory failure. It remains unclear whether NIV has potential as an effective therapeutic method in patients with acute lung injury (ALI). The aims of this study were to determine factors predicting the need for endotracheal intubation in ALI patients treated with NIV, and to promote the selection of patients suitable for NIV.

METHODS

We conducted a retrospective study of all patients admitted to the intensive care unit (ICU) of the Nippon Medical School Hospital from 2000 to 2006 with a diagnosis of ALI, in whom NIV was initiated.

RESULTS

A total of 47 patients with ALI received NIV, and 33 patients (70%) successfully avoided endotracheal intubation. Patients who required endotracheal intubation had a significantly higher Acute Physiology and Chronic Health Evaluation (APACHE) II score and a significantly higher Simplified Acute Physiology Score (SAPS) II, and a significantly lower arterial pH. The respiratory rate decreased significantly within 1 h of starting NIV only in patients successfully treated with NIV. An APACHE II score of more than 17 (P = 0.022) and a respiratory rate of more than 25 breaths x min(-1) after 1 h of NIV (P = 0.024) were independent factors associated with the need for endotracheal intubation. Patients who avoided endotracheal intubation had a significantly lower ICU mortality rate and in-hospital mortality rate than patients who required endotracheal intubation.

CONCLUSION

We determined an APACHE II score of more than 17 and a respiratory rate of more than 25 breaths x min(-1) after 1 h of NIV as factors predicting the need for endotracheal intubation in ALI patients treated with NIV.

Non-invasive positive pressure ventilation (CPAP or bilevel NPPV) for cardiogenic pulmonary edema

BACKGROUND

Non-invasive positive pressure ventilation (NPPV) has been widely used to alleviate signs and symptoms of respiratory distress due to cardiogenic pulmonary edema. NPPV prevents alveolar collapse and helps redistribute intra-alveolar fluid, improving pulmonary compliance and reducing the pressure of breathing.

OBJECTIVES

To determine the effectiveness and safety of NPPV in the treatment of adult patients with cardiogenic pulmonary edema.

SEARCH STRATEGY

We undertook a comprehensive search of the following databases in April 2005: CENTRAL, MEDLINE, EMBASE, CINAHL, DARE and LILACS. We also reviewed reference lists of included studies and contacted experts, equipment manufacturers, and the Cochrane Heart Group. We did not apply language restrictions.

SELECTION CRITERIA

We selected blinded or unblinded randomized or quasi-randomized clinical trials, reporting on adult patients with acute or acute-on-chronic cardiogenic pulmonary edema and where NPPV (continuous positive airway pressure (CPAP)) and/or bilevel NPPV plus standard medical care was compared with standard medical care alone.

DATA COLLECTION AND ANALYSIS

Two authors independently selected articles and abstracted data using a standardized data collection form. We evaluated study quality with emphasis on allocation concealment, adherence to the intention-to-treat principle and losses to follow-up.

MAIN RESULTS

We included 21 studies involving 1,071 participants. Compared to standard medical care, NPPV significantly reduced hospital mortality (RR 0.6, 95% CI 0.45 to 0.84) and endotracheal intubation (RR 0.53, 95% CI 0.34 to 0.83) with numbers needed to treat of 13 and 8, respectively. We found no difference in hospital length of stay with NPPV, however, intensive care unit stay was reduced by 1 day (WMD -1.07 days, 95% CI -1.60 to -0.53). Compared to standard medical care, we did not observe significant increases in the incidence of acute myocardial infarction with NPPV during (RR 1.24, 95% CI 0.79 to 1.95) or after (RR 0.82, 95% CI 0.09 to 7.54) its application.

AUTHORS' CONCLUSIONS

NPPV, especially CPAP, in addition to standard medical care is an effective and safe intervention for the treatment of adult patients with acute cardiogenic pulmonary edema.

Clinical practice guideline: non-invasive mechanical ventilation as treatment of acute respiratory failure

INTRODUCTION

Non-invasive mechanical ventilation (NIV) has been used to treat acute respiratory failure (ARF) for approximately 20 years. This guideline addresses the indications for, and limitations of, NIV as treatment for ARF according to evidence-based criteria.

METHODS

A panel of experts from 12 scientific medical societies reviewed circa 2900 publications. The panel judged the clinical relevance of these studies and assessed the evidence presented in each, then held two interdisciplinary consensus conferences to formulate guideline recommendations and algorithms.

RESULTS

Whenever possible, NIV should be preferred to invasive mechanical ventilation, in order to avoid the risk of ventilator and tube-associated complications such as nosocomial pneumonia (grade of recommendation A). Particularly in patients with hypercapnic ARF, NIV reduces the rate of hospital-acquired pneumonia, the length of hospital stay and mortality in the intensive care unit and in the hospital (grade of recommendation A). NIV (or continuous positive airway pressure) is also recommended in cardiogenic pulmonary edema (grade of recommendation A), as treatment for ARF in immunocompromised patients (grade of recommendation A), to prevent postextubation failure, to facilitate weaning in patients with hypercapnic ARF (grade of recommendation A), and to improve dyspnea in palliative care (grade of recommendation C). NIV is not generally recommended in patients with hypoxic ARF because of its high failure rate of 30% to over 50% in such patients.

DISCUSSION

Although evidence indicates that NIV can be used as the treatment of first choice for several indications, it is still underutilized in the acute setting. These guidelines provide evidence-based information about the indications for, and limitations of, NIV in the treatment of ARF.

Edema e hemorragia pulmonar por pressão negativa associados à obstrução das vias aéreas superiores

O edema pulmonar por pressão negativa associado à hemorragia como manifestação de obstrução das vias aéreas superiores é um problema incomum com potencial risco de morte. O principal mecanismo fisiopatológico envolvido é a geração de uma acentuada pressão negativa intratorácica que eleva tanto o volume vascular como a pressão transmural capilar pulmonar, causando risco de ruptura da membrana alvéolo-capilar. Relatamos o caso de um paciente do sexo masculino com hemorragia alveolar difusa após obstrução aguda das vias aéreas superiores causada pela formação de um abscesso cervical e mediastinal decorrente do implante de uma órtese traqueal metálica. O paciente foi tratado com drenagem do abscesso, antibioticoterapia e ventilação mecânica com pressão positiva. Este artigo enfatiza a importância de incluir essa entidade no diagnóstico diferencial da lesão pulmonar aguda após procedimentos que envolvam a manipulação das vias aéreas superiores.

Noninvasive positive-pressure ventilation in acute respiratory failure outside clinical trials: experience at the Massachusetts General Hospital

BACKGROUND

Noninvasive positive-pressure ventilation (NPPV) has been shown to be effective in select patients enrolled in clinical trials. However, few data are available on the use of NPPV as routine standard medical care for patients with respiratory failure outside of controlled trials.

MEASUREMENTS AND MAIN RESULTS

All patients receiving NPPV for a 1-yr period for acute or acute on chronic respiratory failure who did not select do not intubate/resuscitate status were evaluated. Demographic, physiological, and laboratory data were collected for as long as NPPV was provided. Data were recorded on 449 patients. Intubation rate was 18%, 24%, 38%, 40%, and 60%, respectively, for patients with cardiogenic pulmonary edema (n = 97), acute exacerbation of chronic obstructive pulmonary disease (n = 87), non-chronic obstructive pulmonary disease acute hypercapnic respiratory failure (n = 35), postextubation respiratory failure patients (n = 95), and acute hypoxemic respiratory failure (n = 144). The hospital mortality for patients with acute hypoxemic respiratory failure who failed NPPV was 64%. A logistic regression showed that baseline Simplified Acute Physiology Score II (odds ratio [OR], 1.07; 95% confidence interval [CI], 1.05-1.10; p <.0001), Glasgow Coma Scale (OR, 0.76; 95% CI, 0.66-0.87; p <.0001), PaO2/FIO2 ratio (OR, 0.98; 95% CI, 0.93-0.99; p = .02), and serum albumin (OR, 0.30; 95% CI, 0.16-0.57; p < .001) were the variables associated with NPPV failure.

CONCLUSION

NPPV as routine standard medical care resulted in the intubation of a similar percentage of patients with respiratory failure due to cardiogenic pulmonary edema and chronic obstructive pulmonary disease exacerbation as shown in randomized controlled trials but in a higher percent of patients with hypoxemic respiratory failure than reported in these trials. NPPV failure was associated with high hospital mortality for patients with hypoxemic respiratory failure.

Noninvasive positive pressure ventilation in acute respiratory failure due to COPD vs other causes: effectiveness and predictors of failure in a respiratory ICU in North India

OBJECTIVES

To determine the effectiveness of noninvasive positive pressure ventilation (NIPPV), and the factors predicting failure of NIPPV in acute respiratory failure (ARF) due to chronic obstructive pulmonary disease (COPD) versus other causes of ARF.

PATIENTS AND METHODS

This was a prospective observational study and all patients with ARF requiring NIPPV over a one-and-a-half year period were enrolled in the study. We recorded the etiology of ARF and prospectively collected the data for heart rate, respiratory rate, arterial blood gases (pH, partial pressure of oxygen in the arterial blood [PaO2], partial pressure of carbon dioxide in arterial blood [PaCO2]) at baseline, one and four hours. The patients were further classified into two groups based on the etiology of ARF as COPD-ARF and ARF due to other causes. The primary outcome was the need for endotracheal intubation during the intensive care unit (ICU) stay.

RESULTS

During the study period, 248 patients were admitted in the ICU and of these 63 (25.4%; 24, COPD-ARF, 39, ARF due to other causes; 40 male and 23 female patients; mean [standard deviation] age of 45.7 [16.6] years) patients were initiated on NIPPV. Patients with ARF secondary to COPD were older, had higher APACHE II scores, lower respiratory rates, lower pH and higher PaCO2 levels compared to other causes of ARF. After one hour there was a significant decrease in respiratory rate and heart rate and decline in PaCO2 levels with increase in pH and PaO2 levels in patients successfully managed with NIPPV. However, there was no difference in improvement of clinical and blood gas parameters between the two groups except the rate of decline of pH at one and four hours and PaCO2 at one hour which was significantly faster in the COPD group. NIPPV failures were significantly higher in ARF due to other causes (15/39) than in ARF-COPD (3/24) (p = 0.03). The mean ICU and hospital stay and the hospital mortality were similar in the two groups. In the multivariate logistic regression model (after adjusting for gender, APACHE II scores and improvement in respiratory rate, pH, PaO2 and PaCO2 at one hour) only the etiology of ARF, ie, ARF-COPD, was associated with a decreased risk of NIPPV failure (odds ratio 0.23; 95% confidence interval, 0.58-0.9).

CONCLUSIONS

NIPPV is more effective in preventing endotracheal intubation in ARF due to COPD than other causes, and the etiology of ARF is an important predictor of NIPPV failure.

Noninvasive ventilation in acute respiratory failure

BACKGROUND

Noninvasive ventilation has assumed an important role in the management of respiratory failure in critical care units, but it must be used selectively depending on the patient's diagnosis and clinical characteristics.

DATA

We review the strong evidence supporting the use of noninvasive ventilation for acute respiratory failure to prevent intubation in patients with chronic obstructive pulmonary disease exacerbations or acute cardiogenic pulmonary edema, and in immunocompromised patients, as well as to facilitate extubation in patients with chronic obstructive pulmonary disease who require initial intubation. Weaker evidence supports consideration of noninvasive ventilation for chronic obstructive pulmonary disease patients with postoperative or postextubation respiratory failure; patients with acute respiratory failure due to asthma exacerbations, pneumonia, acute lung injury, or acute respiratory distress syndrome; during bronchoscopy; or as a means of preoxygenation before intubation in critically ill patients with severe hypoxemia.

CONCLUSION

Noninvasive ventilation has assumed an important role in managing patients with acute respiratory failure. Patients should be monitored closely for signs of noninvasive ventilation failure and promptly intubated before a crisis develops. The application of noninvasive ventilation by a trained and experienced intensive care unit team, with careful patient selection, should optimize patient outcomes.