The effect of positive pressure airway support on mortality and the need for intubation in cardiogenic pulmonary edema: a systematic review

Complex Heart-Lung Ventilator Emergencies in the CICU

This review aims to enhance the comprehension and management of cardiopulmonary interactions in critically ill patients with cardiovascular disease undergoing mechanical ventilation. Highlighting the significance of maintaining a delicate balance, this article emphasizes the crucial role of adjusting ventilation parameters based on both invasive and noninvasive monitoring. It provides recommendations for the induction and liberation from mechanical ventilation. Special attention is given to the identification of auto-PEEP (positive end-expiratory pressure) and other situations that may impact hemodynamics and patients' outcomes.

Retrospective evaluation of the outcome and prognosis of undergoing positive pressure ventilation due to cardiac and noncardiac causes in dogs and cats (2019-2020): 101 cases

OBJECTIVE

To compare the short- and long-term outcomes of dogs and cats with left-sided congestive heart failure (L-CHF) undergoing positive pressure ventilation (PPV) to patients undergoing PPV for other causes and to determine risk factors associated with outcomes in this population.

DESIGN

This retrospective study included dogs and cats that underwent PPV during 2018-2020. The study group included patients diagnosed with L-CHF. The control group included patients who were ventilated for reasons other than L-CHF. The risk factors evaluated included vital signs on presentation, ventilator settings, development of azotemia during hospitalization, cardiopulmonary resuscitation (CPR), complications, and medications used.

SETTING

University Teaching Hospital.

ANIMALS

Fifty (32 dogs, 18 cats) study group animals and 51 (39 dogs, 12 cats) control group animals were included in the L-CHF and control groups, respectively.

MEASUREMENTS AND MAIN RESULTS

Sixty-six percent (33/50) of L-CHF patients, compared with 35% (18/51) of the control patients, were weaned off PPV (P = 0.002). Fifty-four percent (27/50) of the L-CHF patients survived to discharge, compared with 26% (13/51) of the control group patients (P = 0.003). However, only 54% (12/22) of the discharged L-CHF patients survived for >2 months compared to 100% of the control patients. The median survival time for dogs and cats with L-CHF surviving to discharge was 240 days (range: 1-730 days). In dogs, factors negatively associated with survival included CPR in both groups and the development of azotemia in the L-CHF group. Anemia on presentation was negatively associated with survival for both cats and dogs in the control group.

CONCLUSIONS

Dogs and cats undergoing PPV due to L-CHF were more commonly weaned off the ventilator and survived to discharge compared to other causes necessitating PPV. However, these patients suffer from severe heart disease, and therefore, their long-term survival is guaranteed.

Mechanical ventilation in cardiogenic shock

PURPOSE OF REVIEW

Mechanical ventilation is frequently needed in patients with cardiogenic shock. The aim of this review is to summarize and discuss the current evidence and the pathophysiological mechanism that a clinician should consider while setting the ventilator.

RECENT FINDINGS

Little attention has been placed specifically to ventilatory strategies in patients with cardiogenic shock undertaking mechanical ventilation. Lung failure in patients with cardiogenic shock is associated with worsening outcome as well as a delay in mechanical ventilation institution. The hemodynamic profile and cardiogenic shock cause, considering the preload dependency of the failing heart, must be defined to adjust ventilatory setting.

SUMMARY

Evidence is growing regarding the role of lung failure as adverse prognostic factor and beneficial effect of positive pressure ventilation as part of first-line treatment in patients with cardiogenic failure.

Utilization and outcomes of early respiratory support in 6.5 million acute heart failure hospitalizations

AIMS

The incidence and outcomes of a requirement for non-invasive ventilation (NIV) or invasive mechanical ventilation (IMV) in acute heart failure (AHF) hospitalization are not clearly established. Thus, we aimed to characterize the incidence and trends in use of IMV and NIV in AHF and to estimate the magnitude of hazard for mortality associated with requiring IMV and NIV in AHF.

METHODS AND RESULTS

We used the National Inpatient Sample (NIS) to identify AHF hospitalizations between 2008 and 2014. The exposure variable of interest was IMV or NIV use within 24 h of hospital admission compared to no respiratory support. We analysed the association between ventilation strategies and in-hospital mortality using Cox proportional hazards models adjusting for demographics and comorbidities. We included 6 534 675 hospitalizations for AHF. Of these, 271 589 (4.16%) included NIV and 51 459 (0.79%) included IMV within the first 24 h of hospitalization and rates of NIV and IMV use increased over time. In-hospital mortality for AHF hospitalizations including NIV was 5.0% and 27% for IMV compared with 2.1% for neither (P < 0.001 for both). In an adjusted model, requirement for NIV was associated with over two-fold higher risk for in-hospital mortality [hazard ratio (HR) 2.10, 95% confidence interval (CI) 2.01-2.19; P < 0.001] and requirement for IMV was associated with over three-fold higher risk for in-hospital mortality (HR 3.39, 95% CI 3.14-3.66; P < 0.001).

CONCLUSION

Respiratory support is used in many AHF hospitalizations, and AHF patients who require respiratory support are at high risk for in-hospital mortality. Our work should inform prospective intervention trials and quality improvement ventures in this high-risk population.

Effect of noninvasive ventilation on intubation risk in prehospital patients with acute cardiogenic pulmonary edema: a retrospective study

OBJECTIVE

The aim of this study was to assess the effect of prehospital noninvasive ventilation for acute cardiogenic pulmonary edema on endotracheal intubation rate and on ICU admission rate.

METHODS

We carried out a retrospective study on patients' prehospital files between 2007 and 2010 (control period), and between 2013 and 2016 (intervention period). Adult patients were included if a diagnosis of acute cardiogenic pulmonary edema was made by the prehospital physician. Exclusion criteria were a Glasgow coma scale score less than 9 or any other respiratory diagnosis. We analyzed the association between noninvasive ventilation implementation and endotracheal intubation or ICU admission with univariable and multivariable regression models. The primary outcome was prehospital endotracheal intubation rate. Secondary outcomes were admission to an ICU, prehospital intervention length, and 30-day mortality.

RESULTS

A total of 1491 patients were included. Noninvasive ventilation availability was associated with a significant decrease in endotracheal intubation rate (2.6% in the control versus 0.7% in the intervention period), with an adjusted odds ratio (OR) of 0.3 [95% confidence interval (CI), 0.1-0.7]. There was a decrease in ICU admissions (18.6% in the control versus 13.0% in the intervention period) with an adjusted OR of 0.6 (95% CI, 0.5-0.9). There was no significant change in 30-day mortality (11.2% in the control versus 11.0% in the intervention period, P = 0.901).

CONCLUSION

In our physician-staffed prehospital system, use of noninvasive ventilation for acute cardiogenic pulmonary edema decreased both endotracheal intubation and ICU admission rates.

Noninvasive Positive Pressure Ventilation for Acute Decompensated Heart Failure

Noninvasive positive pressure ventilation (NIPPV), which can be applied without endotracheal airway or tracheostomy, has been used as the first-line device for patients with acute decompensated heart failure (ADHF) and cardiogenic pulmonary edema. Positive airway pressure (PAP) devices include continuous PAP, bilevel PAP, and adaptive servoventilation. NIPPV can provide favorable physiologic benefits, including improving oxygenation, respiratory mechanics, and pulmonary and systemic hemodynamics. It can also reduce the intubation rate and improve clinical symptoms, resulting in good quality of life and mortality.

Non-Invasive Ventilatory Support In the Elderly

PURPOSE OF REVIEW

The first description of non-invasive ventilation use began in the 1920s. Since then, its role in patient care has evolved through increased clinical knowledge and scientific advancements. The utilization of non-invasive ventilation has broadened from initial application in acute in-hospital ICU settings to now include the outpatient settings. This review discusses the history of non-invasive ventilation and its role in acute in-hospital chronic obstructive pulmonary disease (COPD) exacerbations, cardiogenic pulmonary edema, and weaning from mechanical ventilation in the elderly. The elderly population represents a significant portion of patients hospitalized for the aforementioned conditions. These groups often have more limitations related to the use of invasive mechanical ventilation (IMV), therefore, it is essential to understand the impact of non-invasive ventilation on hospital outcomes.

RECENT FINDINGS

There is strong clinical evidence supporting the use of non-invasive ventilation in patients with respiratory failure secondary to acute COPD exacerbations and cardiogenic pulmonary edema. When compared to standard medical management of these conditions, there is a consistent and significant reduction in the rate of endotracheal intubation and in-hospital mortality.

SUMMARY

The basis of noninvasive ventilation applicability has been determined by significant reduction in mortality and intubation rates. Although survival benefits have been observed, there still remain limitations to the clinical applicability of non-invasive ventilation in certain patient populations and conditions that require further investigation.

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

BACKGROUND

Non-invasive positive pressure ventilation (NPPV) has been used to treat respiratory distress due to acute cardiogenic pulmonary oedema (ACPE). We performed a systematic review and meta-analysis update on NPPV for adults presenting with ACPE.

OBJECTIVES

To evaluate the safety and effectiveness of NPPV compared to standard medical care (SMC) for adults with ACPE. The primary outcome was hospital mortality. Important secondary outcomes were endotracheal intubation, treatment intolerance, hospital and intensive care unit length of stay, rates of acute myocardial infarction, and adverse event rates.

SEARCH METHODS

We searched CENTRAL (CRS Web, 20 September 2018), MEDLINE (Ovid, 1946 to 19 September 2018), Embase (Ovid, 1974 to 19 September 2018), CINAHL Plus (EBSCO, 1937 to 19 September 2018), LILACS, WHO ICTRP, and clinicaltrials.gov. We also reviewed reference lists of included studies. We applied no language restrictions.

SELECTION CRITERIA

We included blinded or unblinded randomised controlled trials in adults with ACPE. Participants had to be randomised to NPPV (continuous positive airway pressure (CPAP) or bilevel NPPV) plus standard medical care (SMC) compared with SMC alone.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened and selected articles for inclusion. We extracted data with a standardised data collection form. We evaluated the risks of bias of each study using the Cochrane 'Risk of bias' tool. We assessed evidence quality for each outcome using the GRADE recommendations.

MAIN RESULTS

We included 24 studies (2664 participants) of adult participants (older than 18 years of age) with respiratory distress due to ACPE, not requiring immediate mechanical ventilation. People with ACPE presented either to an Emergency Department or were inpatients. ACPE treatment was provided in an intensive care or Emergency Department setting. There was a median follow-up of 13 days for hospital mortality, one day for endotracheal intubation, and three days for acute myocardial infarction. Compared with SMC, NPPV may reduce hospital mortality (risk ratio (RR) 0.65, 95% confidence interval (CI) 0.51 to 0.82; participants = 2484; studies = 21; I² = 6%; low quality of evidence) with a number needed to treat for an additional beneficial outcome (NNTB) of 17 (NNTB 12 to 32). NPPV probably reduces endotracheal intubation rates (RR 0.49, 95% CI 0.38 to 0.62; participants = 2449; studies = 20; I² = 0%; moderate quality of evidence) with a NNTB of 13 (NNTB 11 to 18). There is probably little or no difference in acute myocardial infarction (AMI) incidence with NPPV compared to SMC for ACPE (RR 1.03, 95% CI 0.91 to 1.16; participants = 1313; studies = 5; I² = 0%; moderate quality of evidence). We are uncertain as to whether NPPV increases hospital length of stay (mean difference (MD) -0.31 days, 95% CI -1.23 to 0.61; participants = 1714; studies = 11; I² = 55%; very low quality of evidence). Adverse events were generally similar between NPPV and SMC groups, but evidence was of low quality.

AUTHORS' CONCLUSIONS

Our review provides support for continued clinical application of NPPV for ACPE, to improve outcomes such as hospital mortality and intubation rates. NPPV is a safe intervention with similar adverse event rates to SMC alone. Additional research is needed to determine if specific subgroups of people with ACPE have greater benefit of NPPV compared to SMC. Future research should explore the benefit of NPPV for ACPE patients with hypercapnia.

Positive Pressure Ventilation in the Cardiac Intensive Care Unit

Contemporary cardiac intensive care units (CICUs) provide care for an aging and increasingly complex patient population. The medical complexity of this population is partly driven by an increased proportion of patients with respiratory failure needing noninvasive or invasive positive pressure ventilation (PPV). PPV often plays an important role in the management of patients with cardiogenic pulmonary edema, cardiogenic shock, or cardiac arrest, and those undergoing mechanical circulatory support. Noninvasive PPV, when appropriately applied to selected patients, may reduce the need for invasive mechanical PPV and improve survival. Invasive PPV can be lifesaving, but has both favorable and unfavorable interactions with left and right ventricular physiology and carries a risk of complications that influence CICU mortality. Effective implementation of PPV requires an understanding of the underlying cardiac and pulmonary pathophysiology. Cardiologists who practice in the CICU should be proficient with the indications, appropriate selection, potential cardiopulmonary interactions, and complications of PPV.

Cardiorespiratory interaction with continuous positive airway pressure

The treatment of choice for obstructive sleep apnoea (OSA) is continuous positive airway pressure therapy (CPAP). Since its introduction in clinical practice, CPAP has been used in various clinical conditions with variable and heterogeneous outcomes. In addition to the well-known effects on the upper airway CPAP impacts on intrathoracic pressures, haemodynamics and blood pressure (BP) control. However, short- and long-term effects of CPAP therapy depend on multiple variables which include symptoms, underlying condition, pressure used, treatment acceptance, compliance and usage. CPAP can alter long-term cardiovascular risk in patients with cardiorespiratory conditions. Furthermore, the effect of CPAP on the awake patient differs from the effect on the patients while asleep, and this might contribute to discomfort and removal of the use interface. The purpose of this review is to highlight the physiological impact of CPAP on the cardiorespiratory system, including short-term benefits and long-term outcomes.

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

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

Treatment and Outcome of Acute Cardiogenic Pulmonary Oedema Presenting to an Emergency Department in Hong Kong: Retrospective Cohort Study

Objectives

To explore the epidemiology, treatment and outcome of acute cardiogenic pulmonary oedema (ACPO) in a Hong Kong emergency department (ED).

Methods

This was a retrospective cohort study in a university hospital ED. Cases were identified from ED records and resuscitation room logbooks. The study extended from 1 September 2004 to 30 April 2005. Parametric tests and logistic regression were used to identify predictors of survival.

Results

A total of 140 patients were identified, with a mean age of 75 years and male:female ratio of 1:1.4. Mean values (range) on presentation were as follows: pulse rate 103 beats/minute (36–108); blood pressure (BP) 169/88 mmHg (77-274/20-162) and respiratory rate 31 breaths/minute (12–88). Past medical history included previous ACPO (12.1%), diabetes (45.7%), chronic obstructive pulmonary disease (9.3%), ischaemic heart disease (45.0%), hypertension (72.1%) and congestive heart failure (40.7%). On admission, 47.1% had pH<7.35 and 40.7% had PaCO2>5.5kPa. ED treatments included: sublingual nitrates (n=2), intravenous (IV) nitrates (n=89, median 10 mg/hr), IV frusemide (n=85, median 40 mg), IV morphine (n=25, median 3 mg). There were 21 patients on non-invasive ventilation; 27 intubations and 41 patients were admitted to the intensive care unit. Survival to discharge was 95.7%; and median length of hospital stay was 8 days. The 90-day all-cause hospital readmission rate was 30.0%. The 30-day mortality was 12.9% (n=18) and 90-day mortality was 29.3% (n=41). Logistic regression showed that past history of hypertension (p=0.0061), higher systolic BP on ED discharge (p=0.0102) and lower creatinine following treatment (p=0.035) were predictors of improved survival at 90 days.

Conclusion

ACPO commonly presents to the ED in Hong Kong and has a high 90-day mortality. Previous hypertension, higher systolic blood pressure on leaving the ED and lower creatinine following treatment predict improved survival at 90 days.

Noninvasive Mechanical Ventilation in Acute Ventilatory Failure: Rationale and Current Applications

Noninvasive ventilation plays a pivotal role in acute ventilator failure and has been shown, in certain disease processes such as acute exacerbation of chronic obstructive pulmonary disease, to prevent and shorten the duration of invasive mechanical ventilation, reducing the risks and complications associated with it. The application of noninvasive ventilation is relatively simple and well tolerated by patients and in the right setting can change the course of their illness.

Non-Invasive Mechanical Ventilation Versus Continuous Positive Airway Pressure Relating to Cardiogenic Pulmonary Edema in an Intensive Care Unit

BACKGROUND

To compare the application of non-invasive ventilation (NIV) versus continuous positive airway pressure (CPAP) in the treatment of patients with cardiogenic pulmonary edema (CPE) admitted to an intensive care unit (ICU).

METHODS

In a prospective, randomized, controlled study performed in an ICU, patients with CPE were assigned to NIV (n=56) or CPAP (n=54). Primary outcome was intubation rate. Secondary outcomes included duration of ventilation, length of ICU and hospital stay, improvement of gas exchange, complications, ICU and hospital mortality, and 28-day mortality. The outcomes were analyzed in hypercapnic patients (PaCO₂>45mmHg) with no underlying chronic lung disease.

RESULTS

Both devices led to similar clinical and gas exchange improvement; however, in the first 60min of treatment a higher PaO₂/FiO₂ ratio was observed in the NIV group (205±112 in NIV vs. 150±84 in CPAP, P=.02). The rate of intubation was similar in both groups (9% in NIV vs. 9% in CPAP, P=1.0). There were no differences in duration of ventilation, ICU and length of hospital stay. There were no significant differences in ICU, hospital and 28-d mortality between groups. In the hypercapnic group, there were no differences between NIV and CPAP.

CONCLUSIONS

Either NIV or CPAP are recommended in patients with CPE in the ICU. Outcomes in the hypercapnic group with no chronic lung disease were similar using NIV or CPAP.

Helmet CPAP versus Oxygen Therapy in Hypoxemic Acute Respiratory Failure: A Meta-Analysis of Randomized Controlled Trials

PURPOSE

The efficacy of helmet continuous positive airway pressure (CPAP) in hypoxemic acute respiratory failure (hARF) remains unclear. The aim of this meta-analysis was to critically review studies that investigated the effect of helmet CPAP on gas exchange, mortality, and intubation rate in comparison with standard oxygen therapy.

MATERIALS AND METHODS

We performed a meta-analysis of randomized controlled trials (RCTs) by searching the PubMed, Embase, Cochrane library, OVID, and CBM databases, and the bibliographies of the retrieved articles. Studies that enrolled adults with hARF who were treated with helmet CPAP and measured at least one of the following parameters were included: gas exchange, intubation rate, in-hospital mortality rate.

RESULTS

Four studies with 377 subjects met the inclusion criteria and were analyzed. Compared to the standard oxygen therapy, helmet CPAP significantly increased the PaO₂/FiO₂ [weighted mean difference (WMD)=73.40, 95% confidence interval (95% CI): 43.92 to 102.87, p<0.00001], and decreased the arterial carbon dioxide levels (WMD=-1.92, 95% CI: -3.21 to -0.63, p=0.003), intubation rate [relative risk (RR)=0.21, 95% CI: 0.11 to 0.40, p<0.00001], and in-hospital mortality rate (RR=0.22, 95% CI: 0.09 to 0.50, p=0.0004).

CONCLUSION

The results of this meta-analysis suggest that helmet CPAP improves oxygenation and reduces mortality and intubation rates in hARF. However, the significant clinical and statistical heterogeneity of the literature implies that large RCTs are needed to determine the role of helmet CPAP in different hypoxemic ARF populations.

Diagnosing and managing acute heart failure in the emergency department

Heart failure is a clinical syndrome that results from the impairment of ventricular filling or ejection of blood and affects millions of people worldwide. Diagnosis may not be straightforward and at times may be difficult in an undifferentiated patient. However, rapid evaluation and diagnosis is important for the optimal management of acute heart failure. We review the many aspects of diagnosing and treating acute heart failure in the emergency department.

Adaptive Servo-Ventilation Has More Favorable Acute Effects on Hemodynamics Than Continuous Positive Airway Pressure in Patients With Heart Failure

Adaptive servo-ventilation (ASV) has been attracting attention as a novel respiratory support therapy for heart failure (HF). However, the acute hemodynamic effects have not been compared between ASV and continuous positive airway pressure (CPAP) in HF patients.We studied 12 consecutive patients with stable chronic HF. Hemodynamic measurement was performed by right heart catheterization before and after CPAP 5 cmH2O, CPAP 10 cmH2O, and ASV for 15 minutes each.Heart rate, blood pressure, pulmonary capillary wedge pressure (PCWP), and stroke volume index (SVI) were not changed by any intervention. Right atrial pressure significantly increased after CPAP 10 cmH2O (3.6 ± 3.3 to 6.7 ± 1.6 mmHg, P = 0.005) and ASV (4.1 ± 2.6 to 6.8 ± 1.5 mmHg, P = 0.026). Cardiac index was significantly decreased by CPAP 10 cmH2O (2.3 ± 0.4 to 1.9 ± 0.3 L/minute/m(2), P = 0.048), but was not changed by ASV (2.3 ± 0.4 to 2.0 ± 0.3 L/ minute/m(2), P = 0.299). There was a significant positive correlation between baseline PCWP and % of baseline SVI by CPAP 10 cmH2O (r = 0.705, P < 0.001) and ASV (r = 0.750, P < 0.001). ASV and CPAP 10 cmH2O had significantly greater slopes of this correlation than CPAP 5 cmH2O, suggesting that patients with higher PCWP had a greater increase in SVI by ASV and CPAP 10 cmH2O. The relationship between baseline PCWP and % of baseline SVI by ASV was shifted upwards compared to CPAP 10 cmH2O. Furthermore, based on the results of a questionnaire, patients accepted CPAP 5 cmH2O and ASV more favorably compared to CPAP 10 cmH2O.ASV had more beneficial effects on acute hemodynamics and acceptance than CPAP in HF patients.

Update: Acute Heart Failure (VII): Nonpharmacological Management of Acute Heart Failure

Acute heart failure is a major and growing public health problem worldwide with high morbidity, mortality, and cost. Despite recent advances in pharmacological management, the prognosis of patients with acute decompensated heart failure remains poor. Consequently, nonpharmacological approaches are being developed and increasingly used. Such techniques may include several modalities of ventilation, ultrafiltration, mechanical circulatory support, myocardial revascularization, and surgical treatment, among others. This document reviews the nonpharmacological approach in acute heart failure, indications, and prognostic implications.

Positive airway pressure therapy for heart failure

Heart failure (HF) is a life-threatening disease and is a growing public health concern. Despite recent advances in pharmacological management for HF, the morbidity and mortality from HF remain high. Therefore, non-pharmacological approaches for HF are being developed. However, most non-pharmacological approaches are invasive, have limited indication and are considered only for advanced HF. Accordingly, the development of less invasive, non-pharmacological approaches that improve outcomes for patients with HF is important. One such approach may include positive airway pressure (PAP) therapy. In this review, the role of PAP therapy applied through mask interfaces in the wide spectrum of HF care is discussed.

The 2013 Annual Autumn Meeting of the British Society of Heart Failure

16th British Society for Heart Failure Annual Autumn Meeting Queen Elizabeth II Conference Centre, London, UK, 28-29 November 2013 The 16th Annual Meeting for the British Society for Heart Failure took place in the impressive surroundings of the Queen Elizabeth II Conference Centre in Westminster (London, UK). Over the two-day conference, more than 700 delegates attended - the largest number to date. Over 40 talks were delivered by some of the world's experts in heart failure. For 2013, the theme was making sense of acute heart failure - a clinical entity which is frequently encountered, poorly understood, and for which there exists virtually no evidence base for treatment.

Continuous negative extrathoracic pressure or continuous positive airway pressure compared to conventional ventilation for acute hypoxaemic respiratory failure in children

BACKGROUND

Acute hypoxaemic respiratory failure (AHRF) is an important cause of mortality and morbidity in children. Positive pressure ventilation is currently the standard care, however, it does have complications. Continuous negative extrathoracic pressure (CNEP) ventilation or continuous positive airway pressure (CPAP) ventilation delivered via non-invasive approaches (Ni-CPAP) have shown certain beneficial effects in animal and uncontrolled human studies.

OBJECTIVES

To assess the effectiveness of CNEP or Ni-CPAP compared to conventional ventilation in children (at least one month old and less than 18 years of age) with AHRF due to non-cardiogenic causes for improving the mortality or morbidity associated with AHRF.

SEARCH METHODS

We searched CENTRAL 2013, Issue 6, MEDLINE (January 1966 to June week 3, 2013), EMBASE (1980 to July 2013) and CINAHL (1982 to July 2013).

SELECTION CRITERIA

Randomised or quasi-randomised clinical trials of CNEP or Ni-CPAP versus standard therapy (including positive pressure ventilation) involving children (from one month old to less than 18 years at time of randomisation) who met the criteria for diagnosis of AHRF with at least one of the outcomes reported.

DATA COLLECTION AND ANALYSIS

We assessed risk of bias of the included studies using allocation concealment, blinding of intervention, completeness of follow-up and blinding of outcome measurements. We abstracted data on relevant outcomes and estimated the effect size by calculating risk ratio (RR) and risk difference (RD) with 95% confidence intervals (CI).

MAIN RESULTS

We identified two eligible studies: one of CPAP and one of CNEP (published as an abstract). Both were unblinded studies with mainly unclear risk of bias due to lack of adequate information to assess this. The CPAP study enrolled 37 children to oxygen mask and CPAP and reported improvement in respiratory rate and oxygen saturation in both arms after 30 minutes of application. The CNEP study was published as an abstract and included 33 infants with bronchiolitis. In the CNEP study there was a reduction in the fraction of inspired oxygen (FiO2) (less than 30% within one hour of initiation of therapy) in four participants in the CNEP group compared to none in the control group (RR 10.7, 95% CI 0.6 to 183.9). One infant required CPAP and mechanical ventilation in the control group while all infants in the CNEP group were managed without intubation (RR for both outcomes 0.40, 95% CI 0.02 to 9.06). None of the trials reported on mortality. No adverse events were reported in ether of the included trials.

AUTHORS' CONCLUSIONS

There is a lack of well-designed, controlled trials of non-invasive modes of respiratory support in children with AHRF. Studies assessing the outcomes mortality, avoidance of intubation and its associated complications, hospital stay and patient comfort are needed.

Randomized trial of bilevel versus continuous positive airway pressure for acute pulmonary edema

BACKGROUND

Studies have shown different clinical outcomes of noninvasive positive pressure ventilation (NPPV) from those of continuous positive airway pressure (CPAP).

OBJECTIVE

We evaluated whether bilevel positive airway pressure (BPAP) more rapidly improves dyspnea, ventilation, and acidemia without increasing the myocardial infarction (MI) rate compared to continuous positive pressure ventilation (CPAP) in patients with acute cardiogenic pulmonary edema (APE).

METHODS

Patients with APE were randomized to either BPAP or CPAP. Vital signs and dyspnea scores were recorded at baseline, 30 min, 1 h, and 3 h. Blood gases were obtained at baseline, 30 min, and 1 h. Patients were monitored for MI, endotracheal intubation (ETI), lengths of stay (LOS), and hospital mortality.

RESULTS

Fourteen patients received CPAP and 13 received BPAP. The two groups were similar at baseline (ejection fraction, dyspnea, vital signs, acidemia/oxygenation) and received similar medical treatment. At 30 min, PaO2:FIO2 was improved in the BPAP group compared to baseline (283 vs. 132, p < 0.05) and the CPAP group (283 vs. 189, p < 0.05). Thirty-minute dyspnea scores were lower in the BPAP group compared to the CPAP group (p = 0.05). Fewer BPAP patients required intensive care unit (ICU) admission (38% vs. 92%, p < 0.05). There were no differences between groups in MI or ETI rate, LOS, or mortality.

CONCLUSIONS

Compared to CPAP to treat APE, BPAP more rapidly improves oxygenation and dyspnea scores, and reduces the need for ICU admission. Further, BPAP does not increase MI rate compared to CPAP.

The impact of prehospital continuous positive airway pressure on the rate of intubation and mortality from acute out-of-hospital respiratory emergencies

BACKGROUND

Previous studies have demonstrated decreased rates of intubation and mortality with prehospital use of continuous positive airway pressure (CPAP). We sought to validate these findings in a larger observational study.

METHODS

We conducted a before and after observational study of consecutive patients transported by emergency medical services (EMS) during the 12 months before and the 12 months following implementation of a prehospital CPAP protocol for acute respiratory distress. Included were all patients transported by EMS meeting preestablished criteria indicative of acute respiratory distress and CPAP use (patient's problem specified as cardiac, respiratory distress, respiratory disease, or congestive heart failure [CHF]; age ≥ 12 years; chest sounds documented as wheezes or rales; Glascow Coma Scale [GCS] ≥ 11; respiratory rate ≥ 24 breaths per minute; systolic blood pressure ≥ 90 mmHg; and oxygen saturation < 90%). Data were abstracted from ambulance call reports (ACRs) and hospital records. All cases in which "do not resuscitate" (DNR) was documented on the patient chart or ACR or whose in-hospital outcome (death or discharge) was unknown were excluded.

RESULTS

In all, 442 patients met the above criteria. The mean (SD) age was 73.0 (13.9) years, and 51.5% were women. In-hospital mortality rates did not differ for these patients: 17/228 (7.5%) in the before group and 17/214 (7.9%) in the after group (p = 0.85). In-hospital intubation rates were similar for both groups (12.7 vs. 14.5%, p = 0.59). An analysis of the subgroup that had a hospital diagnosis of chronic obstructive pulmonary disease (COPD), CHF, or pulmonary edema (n = 273) showed mortality was somewhat lower in the before group (3/138, 2.2%) than in the after group (8/135, 5.9%) (p = 0.13). In-hospital intubation rates were also similar for both groups in this subgroup analysis (11.6 vs. 9.6%, p = 0.61).

CONCLUSION

In contrast to previous studies, we were unable to demonstrate a decrease in intubation or mortality related to the use of prehospital CPAP. Our findings may be specific to our EMS system but suggest that further large-scale, randomized, controlled trials may be warranted to firmly establish the benefit of prehospital CPAP.

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

BACKGROUND

This is an update of a systematic review previously published in 2008 about non-invasive positive pressure ventilation (NPPV). NPPV has been widely used to alleviate signs and symptoms of respiratory distress due to cardiogenic pulmonary oedema. 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 oedema in its acute stage.

SEARCH METHODS

We searched the following databases on 20 April 2011: CENTRAL and DARE, (The Cochrane Library, Issue 2 of 4, 2011); MEDLINE (Ovid, 1950 to April 2011); EMBASE (Ovid, 1980 to April 2011); CINAHL (1982 to April 2011); and LILACS (1982 to April 2011). We also reviewed reference lists of included studies and contacted experts and equipment manufacturers. We did not apply language restrictions.

SELECTION CRITERIA

We selected blinded or unblinded randomised or quasi-randomised clinical trials, reporting on adult patients with acute or acute-on-chronic cardiogenic pulmonary oedema and where NPPV (continuous positive airway pressure (CPAP) 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 standardised data collection form. We evaluated study quality with emphasis on allocation concealment, sequence generation allocation, losses to follow-up, outcome assessors, selective outcome reporting and adherence to the intention-to-treat principle.

MAIN RESULTS

We included 32 studies (2916 participants), of generally low or uncertain risk of bias. Compared with standard medical care, NPPV significantly reduced hospital mortality (RR 0.66, 95% CI 0.48 to 0.89) and endotracheal intubation (RR 0.52, 95% CI 0.36 to 0.75). We found no difference in hospital length of stay with NPPV; however, intensive care unit stay was reduced by 1 day (WMD -0.89 days, 95% CI -1.33 to -0.45). Compared with standard medical care, we did not observe significant increases in the incidence of acute myocardial infarction with NPPV during its application (RR 1.24, 95% CI 0.79 to 1.95) or after (RR 0.70, 95% CI 0.11 to 4.26). We identified fewer adverse events with NPPV use (in particular progressive respiratory distress and neurological failure (coma)) when compared with standard medical care.

AUTHORS' CONCLUSIONS

NPPV in addition to standard medical care is an effective and safe intervention for the treatment of adult patients with acute cardiogenic pulmonary oedema. The evidence to date on the potential benefit of NPPV in reducing mortality is entirely derived from small-trials and further large-scale trials are needed.

Practical use, effects and complications of prehospital treatment of acute cardiogenic pulmonary edema using the Boussignac CPAP system

BACKGROUND

Early use of continuous positive airway pressure (CPAP) has been shown to be beneficial within the setting of acute cardiogenic pulmonary edema (ACPE). The Boussignac CPAP system (BCPAP) was therefore introduced into the protocols of emergency medical services (EMS) in a large urban region. This study evaluates the implementation, practical use and complications of this prehospital treatment.

METHODS

This was a retrospective case series study. The study was carried out in a period shortly after the implementation of the BCPAP system on all EMS ambulances in the The Hague region. According to protocol, diagnosis of ACPE in the prehospital setting was left to the discretion of the EMS paramedics and the facial mask was applied immediately after the diagnosis had been made. Patients were selected through hospital registration and diagnostic criteria for ACPE. Only those patients showing evident clinical signs of ACPE were included. Patient characteristics, physiologic variables, clinical outcomes and complications were collected from EMS transport reports and hospital records.

RESULTS

Between 1 June 2008 and 30 April 2009 a total of 180 patients were admitted for ACPE. Of these, 76 (42%) had evident clinical signs of ACPE upon presentation and were included. Three patients were transferred and in 14 cases data were missing. Out of the remaining 59 patients, 16 (27%) received BCPAP. In 43 (73%) cases the mask was not applied. For 7 out of 43 cases that were eligible for BCPAP treatment but did not receive the facial mask, an explanation was found in the EMS transport record. No complications were recorded pertaining to using the BCPAP system.

CONCLUSIONS

A significant portion of patients with clinical signs of acute cardiogenic pulmonary edema in the prehospital setting is not treated according to protocol using BCPAP. Based on the small group of patients that actually received BCPAP treatment, the facial mask seems feasible and effective for the treatment of acute cardiogenic pulmonary edema in the prehospital setting.

State of the evidence: mechanical ventilation with PEEP in patients with cardiogenic shock

The need to provide invasive mechanical ventilatory support to patients with myocardial infarction and acute left heart failure is common. Despite the large number of patients requiring mechanical ventilation in this setting, there are remarkably few data addressing the ideal mode of respiratory support in such patients. Although there is near universal acceptance regarding the use of non-invasive positive pressure ventilation in patients with acute pulmonary oedema, there is more concern with invasive positive pressure ventilation owing to its more significant haemodynamic impact. Positive end-expiratory pressure (PEEP) is almost universally applied in mechanically ventilated patients due to benefits in gas exchange, recruitment of alveolar units, counterbalance of hydrostatic forces leading to pulmonary oedema and maintenance of airway patency. The limited available clinical data suggest that a moderate level of PEEP is safe to use in severe left ventricular (LV) dysfunction and cardiogenic shock, and may provide haemodynamic benefits as well in LV failure which exhibits afterload-sensitive physiology.

Acute Heart Failure Treatment

Dyspnea is the predominant symptom for patients with acute heart failure and initial treatment is largely directed towards the alleviation of this. Contrary to conventional belief, not all patients present with fluid overload and the approach to management is rapidly evolving from a solitary focus on diuresis to one that more accurately reflects the complex interplay of underlying cardiac dysfunction and acute precipitant. Effective treatment thus requires an understanding of divergent patient profiles and an appreciation of various therapeutic options for targeted patient stabilization. The key principle within this paradigm is directed management that aims to diminish the work of breathing through situation appropriate ventillatory support, volume reduction and hemodynamic improvement. With such an approach, clinicians can more efficiently address respiratory discomfort while reducing the likelihood of avoidable harm.

Prehospital continuous positive airway pressure for acute respiratory failure: a systematic review and meta-analysis

INTRODUCTION

Acute respiratory failure (ARF) is a common problem encountered by emergency medical services and is associated with significant morbidity, mortality, and health care costs. Continuous positive airway pressure (CPAP) is an integral part of the hospital treatment of acute ARF, predominantly because of congestive heart failure. Intuitively, better patient outcomes may be achieved when CPAP is applied early in the prehospital setting, but there are few outcome studies to validate its use in this setting.

OBJECTIVE

This systematic review and meta-analysis aimed to examine the effectiveness of CPAP in the prehospital setting for patients with ARF.

METHODS

A literature review of bibliographic databases and secondary sources was conducted and potential papers were assessed by two independent reviewers. Included studies were those that compared CPAP therapy (and usual care) with no CPAP for ARF in the prehospital setting. Studies of other methods of noninvasive ventilation were not included. Methodologic quality was assessed using guidelines from the Cochrane Collaboration. Outcomes included the number of intubations, mortality, physiologic parameters, and dyspnea score. Forrest plots were constructed to estimate the pooled effect of CPAP on outcomes.

RESULTS

Five studies (1,002 patients) met the selection criteria--three randomized controlled trials (RCTs), a nonrandomized comparative study, and a retrospective comparative study using chart review. Forty-seven percent of the patients were allocated to the CPAP group. Baseline characteristics were similar between groups. The pooled estimates demonstrated significantly fewer intubations (odds ratio [OR] 0.31; 95% confidence interval [CI] 0.19-0.51) and lower mortality (OR 0.41; 95% CI 0.19-0.87) in the CPAP group.

CONCLUSION

The studies included in this review showed a reduction in the number of intubations and mortality in patients with ARF who received CPAP in the prehospital setting. The results may not be applicable to other health care contexts because of the inherent differences in the organization and staffing of the EMS systems. Information from large RCTs on the efficacy of CPAP initiated early in the prehospital setting is critical to establishing the evidence base underpinning this therapy before ambulance services incorporate CPAP as routine clinical practice.

Out-of-hospital noninvasive ventilation: epidemiology, technology and equipment

Noninvasive ventilation has been utilized successfully in the pre- and out-of-hospital settings for a variety of disorders, including respiratory distress syndrome in neonates, neurologic and pulmonary diseases in infants and children, and heart failure as well as chronic obstructive pulmonary disease in adults. A variety of interfaces as well as mechanical positive pressure devices have been used: simple continuous positive airway pressure devices are available which do not require sophisticated equipment, while a broad spectrum of ventilators have been used to provide bilevel positive airway pressure. Extensive training of transport teams may be important, particularly when utilizing bilevel positive airway pressure in infants and children.

Acute cardiogenic pulmonary oedema: reflecting on the management of an intensive care unit patient

AIM

The aim of this paper is to reflect upon the management interventions of non-invasive ventilation (NIV) and diuretic therapy that were implemented for a patient admitted to an intensive care unit (ICU) with acute cardiogenic pulmonary oedema.

BACKGROUND

Acute pulmonary oedema is a serious and life-threatening complication of acute heart failure, particularly if this results from an ischaemic event. Statistics highlight that of those patients treated for acute cardiogenic pulmonary oedema, approximately only one third were alive after 1 year. Many of these patients will require intensive care management in order to restore homeostasis. It is therefore imperative that nurses understand the condition and the relevant management of it in order to maximize the already poor prognosis.

RESULTS

Using Driscoll's (2000) reflective model to guide critical thinking, this paper reflects on the management of one patient who was admitted to ICU with acute cardiogenic pulmonary oedema as a result of heart failure. Although there are many aspects of patient management that can be explored, specific care interventions that this patient received in relation to NIV and diuretic therapy will be considered. The evidence base for their use, together with the relevant nursing management issues, and patient implications will be critically analysed and outlined.

CONCLUSIONS

This paper identifies that standard therapy for acute cardiogenic pulmonary oedema is largely supportive and aimed at promoting gaseous exchange. It also highlights that nurses have a key role in ensuring that these essential treatments are as efficacious as possible.

RELEVANCE TO CLINICAL PRACTICE

By using a reflective analysis approach, this paper highlights how reflecting on practice improves knowledge and understanding of the use of NIV and diuretic therapy interventions and should facilitate nurses working in ICU to become more competent in ensuring that the treatment provided for acute cardiogenic pulmonary oedema is as successful as possible.

Predicting the success of noninvasive positive pressure ventilation in emergency room for patients with acute heart failure

BACKGROUND

Non-invasive positive pressure ventilation (NPPV) for acute heart failure (AHF) is increasingly used to avoid endotracheal intubation (ETI). We therefore reviewed our experience using respirator management in the emergency room for AHF, and evaluated the predictive factors in the success of NPPV in the emergency room.

METHODS AND RESULTS

Three-hundred forty-three patients with AHF were analyzed. The AHF patients were assigned to either BiPAP-Synchrony (B-S; Respironics, Merrysville, PA, USA) period (2005-2007, n = 176) or BiPAP-Vision (B-V; Respironics) period (2008-2010, n = 167). The rate of carperitide use was significantly increased and dopamine use was significantly decreased in the B-V period. The total length of hospital stay was significantly shorter in the B-V period. AHF patients were also assigned to a failed trial of NPPV followed by ETI (NPPV failure group) or an NPPV success group in the emergency room for each period. NPPV was successfully used in 48 cases in the B-S period, and in 111 cases in the B-V period. Fifty-seven ETI patients included 45 direct ETI and 11 NPPV failure cases in the B-S period, and 16 ETI patients included 10 direct ETI and 6 NPPV failure cases in the B-V period. The pH values were significantly lower in the NPPV failure than in the NPPV success for both periods (7.19 ± 0.10 vs. 7.28 ± 0.11, B-S period, p < 0.05; 7.05 ± 0.08 vs. 7.27 ± 0.14, B-V period, p < 0.001). A pH value of 7.20 produced the optimal balance in the B-S period, while that of 7.03 produced the optimal balance in B-V periods by the ROC curve analysis. The cutoff value of pH was lower in the B-V period than in the B-S period.

CONCLUSIONS

This predictive value provides successful estimates of NPPV with a high sensitivity and specificity, and the aortic blood gas level was above 7.03 pH when using the B-V system.

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.

[Applications of noninvasive mechanical ventilation in anesthesiology and postanesthesia recovery care]

Noninvasive ventilation (NIV) can be useful to anesthesiologists working in critical care units, postanesthesia recovery units, operating theaters, or other settings. NIV can help in situations of acute respiratory failure or serve as a preventive measure in patients undergoing interventions under local-regional anesthesia or diagnostic or therapeutic procedures requiring sedation. Successful NIV depends on adequately trained health personnel and the proper choice of material (interfaces, respirators, etc.) for each setting where this modality is used.

Emergency department stabilization of heart failure

Optimizing heart failure management begins in the emergency department. Prompt recognition and treatment of underlying pathophysiology can improve patient outcomes. A review of therapeutic options is provided, with the goal of providing best practices in patient care.

Noninvasive ventilation in acute cardiogenic pulmonary edema

PURPOSE OF REVIEW

Patients with acute pulmonary edema are often treated with noninvasive ventilation (NIV). There are essentially two modalities used in this setting: continuous positive airway pressure and bilevel pressure support ventilation. The clinical impact of these techniques and the subset of patients who can benefit from their application have not been definitely established.

RECENT FINDINGS

The main advantage of the use of NIV in patients with severe acute pulmonary edema is to avoid intubation by more effectively decreasing respiratory distress with respect to conventional oxygen therapy. These beneficial effects were demonstrated in three meta-analyses including nearly 900 patients. Although neither technique was superior to the other in the comparative analysis, a tendency to reduce hospital mortality was observed, which was statistically significant for continuous positive airway pressure. However, unpublished data from a large multicenter trial comparing both modalities of NIV to conventional treatment in emergency departments did not confirm these results. Recent research has pointed out a clear advantage when the treatment is initiated early in the prehospital setting.

SUMMARY

Although in acute pulmonary edema NIV is more effective in improving respiratory distress than conventional oxygen therapy and reduces the necessity of intubation, the subset of patients who can best benefit from these techniques in terms of mortality still warrant further investigation.

Is helmet CPAP first line pre-hospital treatment of presumed severe acute pulmonary edema?

PURPOSE

Non-invasive continuous positive airway pressure (CPAP) is effective in reducing intubation rate and mortality of patient with acute cardiogenic pulmonary edema (ACPE). We report our experience on pre-hospital application of CPAP by helmet as an adjunct to medical therapy or as a stand alone procedure in patient with presumed ACPE.

METHODS

In pre-hospital treatment of 62 patients with presumed ACPE, CPAP was added to standard medical treatment while in another 59 patients, CPAP was used as a sole therapy.

RESULTS

Helmet CPAP was feasible in all patients. No patient required pre-hospital intubation. In both groups, CPAP significantly improved oxygenation (SpO(2) went from 79 +/- 12 to 97 +/- 3% and from 81 +/- 13 to 98 +/- 3%), reduced respiratory rate (from 26 +/- 4 to 21 +/- 3 bpm and from 30 +/- 9 to 22 +/- 8 bpm) and improved hemodynamics, with a more pronounced decrease in blood pressure in the group with medical treatment than in the one without it. In the two cohorts, four and five patients were, respectively, intubated in Emergency Department and 11 and 9 eventually died.

CONCLUSIONS

Helmet CPAP is feasible, efficient and safe in pre-hospital treatment of presumed ACPE. A significant improvement of physiological variables was observed also in the group treated with CPAP in the absence of a drug therapy. We propose helmet CPAP as first line pre-hospital treatment of presumed severe ACPE.

Prehospital noninvasive ventilation: a viable treatment option in the urban setting

OBJECTIVE

To determine the viability of prehospital noninvasive ventilation (NIV) as a prelude to a definitive clinical trial.

METHODS

This was a retrospective observational study of patients (aged > 55 years, severe shortness of breath) transported to a tertiary emergency department (10/5/03-12/28/04). Data were extracted from paramedic and hospital medical records. The primary outcome measure was the number of patients who could potentially benefit from prehospital NIV. They were defined as "conscious upon paramedic arrival and who required ventilatory support (bag/valve/mask ventilation [BVM], NIV or endotracheal intubation) during transport or within 30 minutes of arrival at the emergency department (ED)." The secondary outcome measures were the effectiveness of existing paramedic treatment regimens and paramedic management times.

RESULTS

Two hundred sixty-four patients were enrolled (mean age 75.5 +/- 8.7 years, 59.1% male). Sixty-seven patients (25.4%, 95% CI: 20.3-31.2) met the primary outcome measure: 31 (11.7%, 95% CI: 8.2-16.4) received prehospital BVM, an additional 35 (13.3%, 95% CI: 9.5-18.1) received NIV in the ED and one (0.4%, 95% CI: 0.0-2.4) was intubated in the ED. Prehospital treatment resulted in significant (p < 0.001) improvements in systolic blood pressure (151.2 dropping to 144.2 mmHg), respiratory rate (29.4 dropping to 26.3 breaths/minute), and oxygen saturation (92.3% rising to 96.2%). Median paramedic management time was 33 minutes (IQR 29-40).

CONCLUSION

Prehospital treatment significantly improved patient vital signs. However, a considerable proportion of patients still required ventilatory support either prehospital or early in their ED course. Further research is indicated to determine if these patients would benefit from prehospital NIV.

Predictors of successful noninvasive ventilation treatment for patients suffering acute respiratory failure

BACKGROUND

To identify predictors of successful noninvasive ventilation (NIV) treatment for patients with acute respiratory failure.

METHODS

This was a prospective intervention study of the intensive care unit of a teaching hospital in Chia-Yi, Taiwan. Patients were enrolled if they had acute respiratory failure and had been admitted to the intensive care unit of our hospital between October 1, 2004 and September 30, 2005 inclusively.

RESULTS

All 86 patients who satisfied the study's inclusion criteria agreed to participate in the study, and each patient was followed-up until the discontinuation of NIV treatment or their death. We measured the Acute Physiology and Chronic Health Evaluation (APACHE) II score prior to their treatment and also conducted serial measurements of respiratory rate (RR), tidal volume, rapid shallow breathing index, maximal inspiratory pressure (PImax), and maximal expiratory pressure (PEmax) prior to, and 30 minutes and 60 minutes subsequent to NIV treatment (denoted by, respectively, the subscripted numbers 0, 30 and 60). NIV treatment was determined as being successful for 55 patients (the success group, for which individuals endotracheal intubation was avoided) and as being a failure for 31 patients (the failure group). APACHE II scores prior to treatment, PImax30 (PImax 30 minutes subsequent to NIV), RR30 (RR 30 minutes subsequent to NIV), and RR60 (RR 60 minutes subsequent to NIV) were all significantly lower for the success group than for the failure group. The success group also had significantly better values for RR during the first 30 minutes of NIV treatment and for PEmax during the first 60 minutes of NIV treatment compared to individuals from the failure group.

CONCLUSION

APACHE II scores recorded prior to NIV treatment, PImax30, RR30, RR60, as well as improvements to RR during the first 30 minutes of NIV treatment and to PEmax during the first 60 minutes of NIV treatment were predictors of successful NIV treatment for patients suffering from acute respiratory failure. Such parameters may be helpful in selecting patients to receive NIV treatment and also for deciding when early termination of the treatment is appropriate.