Incidence and causes of non-invasive mechanical ventilation failure after initial success

Assessment of some inflammatory biomarkers as predictors of outcome of acute respiratory failure on top of chronic obstructive pulmonary disease and evaluation of the role of bacteria

Objective. To study the value of the inflammatory markers (interleukin-6 (IL-6), interleukin-8 (IL-8), and C-reactive protein (CRP)) in predicting the outcome of noninvasive ventilation (NIV) in the management of acute respiratory failure (ARF) on top of chronic obstructive pulmonary disease (COPD) and the role of bacteria in the systemic inflammation. Methods. Thirty three patients were subjected to standard treatment plus NIV, and accordingly, they were classified into responders and nonresponders. Serum samples were collected for IL-6, IL-8, and CRP analysis. Sputum samples were taken for microbiological evaluation. Results. A wide spectrum of bacteria was revealed; Gram-negative and atypical bacteria were the most common (31% and 28% resp.; single or copathogen). IL-8 and dyspnea grade was significantly higher in the non-responder group (P = 0.01 and 0.023 resp.). IL-6 correlated positivity with the presence of infection and type of pathogen (P = 0.038 and 0.034 resp.). Gram-negative bacteria were associated with higher significant IL-6 in comparison between others (196.4 ± 239.1 pg/dL; P = 0.011) but insignificantly affected NIV outcome (P > 0.05). Conclusions. High systemic inflammation could predict failure of NIV. G-ve bacteria correlated with high IL-6 but did not affect the response to NIV.

Outcomes of noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease in the United States, 1998-2008

RATIONALE

The patterns and outcomes of noninvasive, positive-pressure ventilation (NIPPV) use in patients hospitalized for acute exacerbations of chronic obstructive pulmonary disease (COPD) nationwide are unknown.

OBJECTIVES

To determine the prevalence and trends of noninvasive ventilation for acute COPD.

METHODS

We used data from the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample to assess the pattern and outcomes of NIPPV use for acute exacerbations of COPD from 1998 to 2008.

MEASUREMENTS AND MAIN RESULTS

An estimated 7,511,267 admissions for acute exacerbations occurred from 1998 to 2008. There was a 462% increase in NIPPV use (from 1.0 to 4.5% of all admissions) and a 42% decline in invasive mechanical ventilation (IMV) use (from 6.0 to 3.5% of all admissions) during these years. This was accompanied by an increase in the size of a small cohort of patients requiring transition from NIPPV to IMV. In-hospital mortality in this group appeared to be worsening over time. By 2008, these patients had a high mortality rate (29.3%), which represented 61% higher odds of death compared with patients directly placed on IMV (95% confidence interval, 24-109%) and 677% greater odds of death compared with patients treated with NIPPV alone (95% confidence interval, 475-948%). With the exception of patients transitioned from NIPPV to IMV, in-hospital outcomes were favorable and improved steadily year by year.

CONCLUSIONS

The use of NIPPV has increased significantly over time among patients hospitalized for acute exacerbations of COPD, whereas the need for intubation and in-hospital mortality has declined. However, the rising mortality rate in a small but expanding group of patients requiring invasive mechanical ventilation after treatment with noninvasive ventilation needs further investigation.

Noninvasive ventilation and weaning in patients with chronic hypercapnic respiratory failure: a randomized multicenter trial

RATIONALE

The use of noninvasive ventilation (NIV) as an early weaning/extubation technique from mechanical ventilation remains controversial.

OBJECTIVES

To investigate NIV effectiveness as an early weaning/extubation technique in difficult-to-wean patients with chronic hypercapnic respiratory failure (CHRF).

METHODS

In 13 intensive care units, 208 patients with CHRF intubated for acute respiratory failure (ARF) who failed a first spontaneous breathing trial were randomly assigned to three groups: conventional invasive weaning group (n = 69), extubation followed by standard oxygen therapy (n = 70), or NIV (n = 69). NIV was permitted as rescue therapy for both non-NIV groups if postextubation ARF occurred. Primary endpoint was reintubation within 7 days after extubation. Secondary endpoints were: occurrence of postextubation ARF or death within 7 days after extubation, use of rescue postextubation NIV, weaning time, and patient outcomes.

MEASUREMENTS AND MAIN RESULTS

Reintubation rates were 30, 37, and 32% for invasive weaning, oxygen-therapy, and NIV groups, respectively (P = 0.654). Weaning failure rates, including postextubation ARF, were 54, 71, and 33%, respectively (P < 0.001). Rescue NIV success rates for invasive and oxygen-therapy groups were 45 and 58%, respectively (P = 0.386). By design, intubation duration was 1.5 days longer for the invasive group than in the two others. Apart from a longer weaning time in NIV than in invasive group (2.5 vs. 1.5 d; P = 0.033), no significant outcome difference was observed between groups.

CONCLUSIONS

No difference was found in the reintubation rate between the three weaning strategies. NIV decreases the intubation duration and may improve the weaning results in difficult-to-wean patients with CHRF by reducing the risk of postextubation ARF. The benefit of rescue NIV in these patients deserves confirmation.

Early predictors of success of non-invasive positive pressure ventilation in hypercapnic respiratory failure

BACKGROUND

Non-invasive positive pressure ventilation (NIPPV) has emerged as a significant advancement in the management of acute hypercapnic respiratory failure.

METHOD

Patients with hypercapnic respiratory failure requiring ventilation therapy (respiratory rate [RR] of > 30 breaths per minutes, PaCO2 > 55 mmHg and arterial pH < 7.35) were included in the study. Baseline clinical parameters and arterial blood gas (ABG) were recorded before initiating NIPPV. Clinical parameters including heart rate (HR), RR, oxygen saturation and ABG were revaluated at 1, 4, and 24 hours after initiation of NIPPV. Change in these parameters and need for intubation was evaluated.

RESULTS

Of the 100 patients, 76 (76%) showed improvement in clinical parameters and ABG. There was improvement in HR and RR, pH, and PCO2 within the first hour in the success group and these parameters continued to improve even after four and 24 hours of NIPPV treatment. Out of 24 (24%) patients who failed to respond, 13 (54%) needed endotracheal intubation within one hour. The failure group had higher baseline HR than the success group.

CONCLUSION

Improvement in HR, RR, pH, and PCO2 one hour after putting the patient on NIPPV predicts success of non-invasive positive pressure ventilation in hypercapnic respiratory failure.

Acute lung failure

Lung failure is the most common organ failure seen in the intensive care unit. The pathogenesis of acute respiratory failure (ARF) can be classified as (1) neuromuscular in origin, (2) secondary to acute and chronic obstructive airway diseases, (3) alveolar processes such as cardiogenic and noncardiogenic pulmonary edema and pneumonia, and (4) vascular diseases such as acute or chronic pulmonary embolism. This article reviews the more common causes of ARF from each group, including the pathological mechanisms and the principles of critical care management, focusing on the supportive, specific, and adjunctive therapies for each condition.

[Evidence-based medicine: implications from the guideline "non-invasive ventilation" in critically ill elderly patients]

The demographic shift means that there are an increasing number of elderly critically ill patients with various comorbidities. This very specific group needs particular treatment which has not been considered sufficiently in medical guidelines so far. To improve health care, it is indispensable not only to work out the current guidelines, but aspects of geriatric medicine must also be integrated into future developments. Using the example of the recent guideline "non-invasive ventilation," it is shown how the process of designing and implication can actively be realized in clinical daily routine.

Phase II study of tight glycaemic control in COPD patients with exacerbations admitted to the acute medical unit

BACKGROUND

Hyperglycaemia is associated with poor outcomes from exacerbations of chronic obstructive pulmonary disease (COPD). Glycaemic control could improve outcomes by reducing infection, inflammation and myopathy. Most patients with COPD are managed on the acute medical unit (AMU) outside intensive care (ICU).

OBJECTIVE

To determine the feasibility, safety and efficacy of tight glycaemic control in patients on an AMU.

DESIGN

Prospective, non-randomised, phase II, single-arm study of tight glycaemic control in COPD patients with acute exacerbations and hyperglycaemia admitted to the AMU. Participants received intravenous, then subcutaneous, insulin to control blood glucose to 4.4-6.5 mmol/l. Tight glycaemic control was evaluated: feasibility, protocol adherence; acceptability, patient questionnaire; safety, frequency of hypoglycaemia (capillary blood glucose (CBG) <2.2 mmol/l and 2.2-3.3 mmol/l); efficacy, median CBG, fasting CBG, proportion of measurements/time in target range, glycaemic variability.

RESULTS

were compared with 25 published ICU studies. Results 20 patients (10 females, age 71 ± 9 years; forced expiratory volume in 1 s: 41 ± 16% predicted) were recruited. Tight glycaemic control was feasible (78% CBG measurements and 89% of insulin-dose adjustments were adherent to protocol) and acceptable to patients. 0.2% CBG measurements were <2.2 mmol/l and 4.1% measurements 2.2-3.3 mmol/l. The study CBG and proportion of measurements/time in target range were similar to that of ICU studies, whereas the fasting CBG was lower, and the glycaemic variability was greater.

CONCLUSIONS

Tight glycaemic control is feasible and has similar safety and efficacy on AMU to ICU. However, as more recent ICU studies have shown no benefit and possible harm from tight glycaemic control, alternative strategies for blood glucose control in COPD exacerbations should now be explored. Trial registration number ISRCTN: 42412334. http://Clinical.Trials.gov NCT00764556.

COPD exacerbation: mortality prognosis factors in a respiratory care unit

OBJECTIVE

The aim of our study was to investigate the mortality predictive factors after a severe exacerbations of COPD admitted to a Spanish respiratory intermediate care unit (IRCU).

PATIENTS AND METHODS

Prospective observational 2 years study, where we included all episodes of acute exacerbations of COPD with hypercapnic respiratory failure admitted in an IRCU. We analyzed different sociodemographic, functional and clinical variables including physical activity.

RESULTS

We collected data from 102 consecutive episodes admitted to IRCU (90.1% men). Mean age was 69.4±10.6. The mean APACHE II was 19.6±5.0 and 9.5% presented a failure of other non respiratory organ. Non invasive ventilation was applied in 75.3% of the episodes and this treatment failed in 11.6% of them. The duration of stay in the IRCU was 3.5±2.1 days and 8.0±5.3 days in the hospital. The hospital mortality rate was 6.9%, and another 12.7% after 90 days of discharged. In order to predict hospital mortality, multivariant statistics identified a model with AUC of 0.867, based in 3 variables: the number of previous year admission for COPD exacerbation (p=0,048), the respiratory rate after 2 hours of treatment in the IRCU (p=0.0484) and the severity of the disease established with ADO score (p=0.0241).

CONCLUSIONS

The number of previous year admission for COPD exacerbation, the severity of the disease established with ADO score, the respiratory rate after 2 hours of treatment, allow us to identify what patients with a COPD exacerbation admitted in a IRCU can die during this episode.

Acidemia does not affect outcomes of patients with acute cardiogenic pulmonary edema treated with continuous positive airway pressure

Introduction

A lack of data exists in the literature evaluating acidemia on admission as a favorable or negative prognostic factor in patients with acute cardiogenic pulmonary edema (ACPE) treated with non-invasive continuous positive airway pressure (CPAP). The objective of the present study was to investigate the impact of acidemia on admission on outcomes of ACPE patients treated with CPAP.

Methods

This was a retrospective, observational study of consecutive patients admitted with a diagnosis of ACPE to the Emergency Department of IRCCS Fondazione Cà Granda Ospedale Maggiore Policlinico, Milan, Italy, between January 2003 and December 2006, treated with CPAP on admission. Two groups of patients were identified: subjects with acidemia (acidotic group), and those with a normal pH on admission (controls). The primary endpoint was clinical failure, defined as switch to bi-level ventilation, switch to endotracheal intubation or inhospital mortality.

Results

Among the 378 patients enrolled, 290 (77%) were acidotic on admission. A total of 28 patients (9.7%) in the acidotic group and eight patients (9.1%) among controls experienced a clinical failure (odds ratio = 1.069, 95% confidence interval = 0.469 to 2.438, P = 0.875). Survival analysis indicates that, among acidotic patients, the time at which 50% of patients reached the 7.35 threshold was 173 minutes (95% confidence interval = 153 to 193). Neither acidemia (P = 0.205) nor the type of acidosis on admission (respiratory acidosis, P = 0.126; metabolic acidosis, P = 0.292; mixed acidosis, P = 0.397) affected clinical failure after adjustment for clinical and laboratory factors in a multivariable logistic regression model.

Conclusions

Neither acidemia nor the type of acidosis on admission should be considered risk factors for adverse outcomes in ACPE patients treated with CPAP.

Noninvasive ventilation in adults with acute respiratory distress: a primer for the clinician

Noninvasive ventilation (NIV) has become an integral part of critical care management. Despite > 2 decades of experience, it is relatively underused, with general utilization reported as a little over 10% in a recent international survey. Lack of training, knowledge, equipment, and experience with NIV may account for its slow adoption. Patient selection, staff training and experience, and prompt recognition of ineffective NIV are important components to successful application of NIV. Noninvasive ventilation does have a learning curve that may be steep for some institutions but must be mastered if the procedure is to become a successful institutional component of care. Patients with acute respiratory failure due to chronic obstructive pulmonary disease or congestive heart failure are ideal candidates for NIV, and optimal efficacy in associated conditions is often linked to these 2 conditions. Technical issues and written guidelines are addressed, including details of an adequate trial of therapy as well as criteria for intubation. Attention to these elements should increase the success rate of NIV, which in turn should increase its general use.

Non-invasive ventilation for acute exacerbations of COPD

Acute exacerbations of chronic obstructive pulmonary disease (COPD) causing respiratory failure are associated with mortality rates of up to 26%. A new Royal College of Physicians guideline aims to impart standards and practical advice to those providing a non-invasive ventilation service for these patients. This article examines the guideline.

Bi-Level Positive Airway Pressure Ventilation in Pediatric Oncology Patients With Acute Respiratory Failure

The aim of the study was to describe our experience with bi-level positive airway pressure (BiPAP) ventilation in oncology children with acute respiratory failure, hospitalized in a single tertiary pediatric tertiary center. This was a retrospective cohort study of all pediatric oncology patients in our center admitted to the intensive care unit with acute hypoxemic or hypercarbic respiratory failure from January 1999 through May 2006, who required mechanical ventilation with BiPAP. Fourteen patients met the inclusion criteria with a total of 16 events of respiratory failure or impending failure: 12 events were hypoxemic, 1 was combined hypercarbic and hypoxemic, and 3 had severe respiratory distress. Shortly after BiPAP ventilation initiation, there was a statistically significant improvement in the respiratory rate (40.4 ± 9.3 to 32.5 ± 10.1, P < .05] and a trend toward improvement in arterial partial pressure of oxygen (PaO 2; 71.3 ± 32.7 to 104.6 ± 45.6, P = .055). The improvement in the respiratory status was sustained for at least 12 hours. In 12 (75%) events there was a need for sedation during ventilation; 12 children needed inotropic support during the BiPAP ventilation. Bi-level positive airway pressure ventilation failed in 3 (21%) children who were switched to conventional ventilation. All of them have died during the following days. One child was recategorized to receive palliative care while on BiPAP ventilator and was not intubated. In 12 of 16 BiPAP interventions (75%; 11 patients), the children survived to pediatric intensive care unit (PICU) discharge without invasive ventilation. No major complications were noted during BiPAP ventilation. Bi-level positive airway pressure ventilation is well tolerated in pediatric oncology patients suffering from acute respiratory failure and may offer noninferior outcomes compared with those previously described for conventional invasive ventilation. It appears to be a feasible initial option in children with malignancy experiencing acute respiratory failure.

Noninvasive ventilation as ceiling of therapy in end-stage chronic obstructive pulmonary disease

The benefits of noninvasive ventilation (NIV) for acute hypercapnic respiratory failure caused by chronic obstructive pulmonary disease (COPD) are well recognized and consequently its use is widespread. Prognostication in advanced COPD is imperfect, limiting accurate identification of 'end-stage' COPD. Decisions regarding withholding invasive ventilation are largely dependent upon prognostication. In patients where 'invasive' ventilation is not considered to be in their best interests, NIV will be the ceiling of therapy. In this patient group, NIV is extremely valuable in reducing mortality and providing valuable symptomatic benefit. We discuss the use of NIV in the management of an acute exacerbation of 'end-stage' COPD where NIV is the ceiling of therapy, the use of advanced directives and the implications of the Mental Capacity Act 2005 on decisions regarding end-of-life care. We highlight areas where further research would be useful.

The metabolic syndrome, diabetes and lung dysfunction

Sleep-disordered breathing and sleep apnoea are conditions frequently associated with comorbidity, including obesity, diabetes, hypertension, insulin resistance (metabolic syndrome) and cardiovascular disease. The diabetic state (type 1 and type 2 diabetes) may be associated to diminished lung function and, in particular, decreased vital capacity, and the association between chronic obstructive pulmonary disease (COPD) and type 2 diabetes may be due to a shared inflammatory process. Also, the alteration in circulating endothelial progenitor cells found in respiratory disease, the metabolic syndrome and cardiovascular disease reflect a common condition of endothelial dysfunction.

Noninvasive mechanical ventilation in patients with chronic obstructive pulmonary disease and severe hypercapnic neurological deterioration in the emergency room

OBJECTIVES

The objective of this study was to assess the effectiveness of noninvasive motion ventilation (NIMV) in patients with chronic obstructive pulmonary disease (COPD), having infectious exacerbation and severe hypercapnic neurological dysfunction in the emergency room.

DESIGN

This is a prospective interventional study.

SETTING

The study setting was the emergency room at the Military Hospital in Guayaquil, Ecuador.

PATIENTS

A total of 24 patients were studied. Twelve patients had acute exacerbation of their chronic obstructive pulmonary disease: they presented at the emergency room with severe neurological dysfunction, with a Glasgow Coma Scale (GCS) score of less than 8 and a pH of less than 7.25. These patients were compared with 12 controls who were being treated with invasive mechanical ventilation (IMV), who were then matched according to their GCS scores, pH status, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, and age.

INTERVENTIONS

We evaluated the effectiveness and safety of applying a ventilatory strategy based on a biphasic positive airway pressure protocol in the emergency room.

MEASUREMENTS AND RESULTS

The pH, PCO2, and GCS scores, measured during the first 3 h, were predictors of success for the application of NIMV treatment (P<0.05). Mortality was 33.3 and 16.7% for the IMV and the NIMV groups, respectively (P=0.01). Days of IMV were 5.60+/-1.2 versus 3.6+/-1.1 for NIMV (P=0.006). Days of hospitalization were 11.1+/-4.7 for the IMV group and 6.5+/-1.9 for the NIMV group (P=0.001). The cumulative survival rates at 6 months were 71.4 and 80% for the IMV and NIMV groups, respectively (P=0.80).

CONCLUSION

We consider that severe neurological dysfunction and pH of less than 7.25 do not constitute absolute contraindications to the use of NIMV. This kind of management can be implemented in the emergency room with favorable results.

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.

[Design of a lung simulator for teaching lung mechanics in mechanical ventilation]

Over the last 10 years, noninvasive ventilation has become a treatment option for respiratory insufficiency in pulmonology services. The technique is currently included in pulmonology teaching programs. Physicians and nurses should understand the devices they use and the interaction between the patient and the ventilator in terms of respiratory mechanics, adaptation, and synchronization. We present a readily assembled lung simulator for teaching purposes that is reproducible and interactive. Based on a bag-in-box system, this model allows the concepts of respiratory mechanics in mechanical ventilation to be taught simply and graphically in that it reproduces the patterns of restriction, obstruction, and the presence of leaks. It is possible to demonstrate how each ventilation parameter acts and the mechanical response elicited. It can also readily simulate asynchrony and demonstrate how this problem can be corrected.

Noninvasive Ventilation Using a Mouthpiece in Patients with Chronic Obstructive Pulmonary Disease and Acute Respiratory Failure

BACKGROUND

Noninvasive positive pressure ventilation (NPPV) delivered via a mouthpiece (mNPPV) has been successfully used in stable chronic restrictive respiratory insufficiency, but not in patients with chronic obstructive pulmonary disease (COPD) and acute respiratory failure (ARF).

OBJECTIVES

The purpose of this matched case-control study was to compare the usefulness of mNPPV to noninvasive ventilation using a nasal or oronasal mask (nNPPV) or standard medical treatment (SMT) in COPD patients with ARF.

METHODS

Twenty-nine patients receiving mNPPV were matched with 29 patients receiving nNPPV and 29 patients receiving SMT regarding age, SAPSII, admission PaCO(2) and pH.

RESULTS

In the mNPPV group, admission PaCO(2) and pH were 78.6 +/- 12 mm Hg and 7.30 +/- 0.04, respectively. mNPPV and nNPPV avoided the need for endotracheal intubation in 27 and 25 patients, respectively (nonsignificant) whereas SMT resulted in a higher mechanical ventilation rate (13 patients). At the end of the treatment protocol, PaCO(2) was lower in the mNPPV group (62.2 +/- 9.6 mm Hg) than in the SMT group (72.4 +/- 20.4 mm Hg, p < 0.018) leading to a significantly higher pH. No significant differences were observed between the mNPPV and nNPPV groups.

CONCLUSIONS

In case of moderate respiratory acidosis, noninvasive ventilation using a mouthpiece significantly reduces the endotracheal intubation rate in comparison with SMT and therefore appears to be a second-line alternative to noninvasive ventilation delivered via a mask, especially when poorly tolerated.

Ventilatory management in patients with chronic airflow obstruction

Mechanical ventilatory support allows patients who have CAO to gain time for pharmacologic treatment to work and to avoid and/or recover from respiratory muscle fatigue. The cornerstone to avoiding associated morbidity with mechanical ventilation in these patients is to prevent dynamic hyperinflation of the lung by limiting minute ventilation and maximizing time for expiration and by inducing synchronization between the patient and mechanical ventilator. When mechanical ventilation is necessary, NPPV should be considered first, whenever possible, in these patients. Patients who have CAO requiring mechanical ventilatory support have an increased risk of death following such an event. Therefore, careful followup is needed after hospital discharge.

The pathophysiology of emphysema: considerations for critical care nursing practice

Emphysema is caused by exposure to cigarette smoking as well as alpha(1)-antitrypsin deficiency. It has been estimated to cost the National Health Service (NHS) in excess of 800 million pounds per year in related health care costs. The challenges for Critical Care nurses are those associated with dynamic hyperinflation, Auto-PEEP, malnutrition and the weaning from invasive and non-invasive mechanical ventilation. In this paper we consider the impact of the pathophysiology of emphysema, its effects on other body systems as well as the impact acute exacerbations have when patients are admitted to the Intensive Care Unit.

Management of acute ventilatory failure

Acute ventilatory failure is a challenging yet increasingly common medical emergency reflecting the growing burden of respiratory disease. It is not a diagnosis in itself but the end result of a diversity of disease processes culminating in arterial hypoxaemia and hypercapnia. This review focuses on key management issues including giving appropriate oxygen therapy, treatment of the underlying aetiology as well as any precipitant factors and provision of assisted ventilation if required. Ventilatory assistance can be provided both invasively and non-invasively and the indications for either or both forms of assisted ventilation are discussed. Further emphasis is needed regarding advanced directives of care and clinicians should be aware of ethical issues regarding assisted ventilation.

The use of noninvasive mechanical ventilation in COPD with severe hypercapnic acidosis

STUDY OBJECTIVES

To compare the effect of noninvasive mechanical ventilation (NIV) in severely acidotic with mildly acidotic patients with acute hypercapnic chronic obstructive lung disease (COPD).

DESIGN

Comparison of NIV in consecutively enrolled patients with acute hypercapnic COPD with mild (pH 7.25-7.35) or severe (pH<7.25) acidosis on time to normalise pH and improve PaCO(2), duration of NIV treatment, length of stay in hospital and survival. Results (meadian (IQR)): Twenty-nine patients had 36 episodes of acute hypercapnic respiratory failure: Seventeen with pH<7.25 and 19 with pH 7.25-7.34. Compared with the mildly acidotic group, the severely acidotic group took a similar length of time for pH to normalise and PaCO(2) improve (12 (6-34) vs 12 (4-28)h, respectively, P=0.42), with similar duration of NIV treatment (60 (35-96) vs 68 (36-48)h, respectively, P=0.25) and hospital length of stay (8 (7-18) vs 9 (5-17) days, respectively, P=0.61). Overall survival was 89%, with 95% in the mild and 82% in the severely acidotic groups.

CONCLUSIONS

Noninvasive ventilation is effective in the treatment of patients with severe acidosis due to acute hypercapnic COPD.

Airway management and artificial ventilation in intensive care

PURPOSE OF REVIEW

This article defines the indication for airway-securing measures and describes the actual state of knowledge about the available techniques. Various modes of ventilation and their rationale are presented.

RECENT FINDINGS

New techniques in airway management and ventilation strategy are presented, explained and evaluated.

SUMMARY

Respiratory failure is a major confounding factor of morbidity and mortality in critical care patients and contributes considerably to prolonged intensive-care unit stay. When respiratory impairment is acute, rapid assessment of essential respiratory functions such as airway patency, gas exchange, and cough function have the highest priority in patients in life-threatening conditions. Securing the airway is a basic and vital procedure that has to be applied either in an elective or an emergency situation. Various levels of difficulty in laryngoscopy, intubation and maintaining oxygenation can occur and require standardized protocols, an adequate level of expertise and appropriate equipment. In intubated patients as well as in patients without secured airway, ventilatory assistance of various degrees and invasivities may be required. In this article all clinically applied forms of ventilation, their advantages and disadvantages as well as the relevant settings are extensively presented and discussed.

Time of non-invasive ventilation

Non-invasive ventilation (NIV) is a safe, versatile and effective technique that can avert side effects and complications associated with endotracheal intubation. The success of NIV relies on several factors, including the type and severity of acute respiratory failure, the underlying disease, the location of treatment, and the experience of the team. The time factor is also important. NIV is primarily used to avert the need for endotracheal intubation in patients with early-stage acute respiratory failure and post-extubation respiratory failure. It can also be used as an alternative to invasive ventilation at a more advanced stage of acute respiratory failure or to facilitate the process of weaning from mechanical ventilation. NIV has been used to prevent development of acute respiratory failure or post-extubation respiratory failure. The number of days of NIV and hours of daily use differ, depending on the severity and course of the acute respiratory failure and the timing of application. In this review article, we analyse, compare and discuss the results of studies in which NIV was applied at various times during the evolution of acute respiratory failure.

Use of Drotrecogin Alpha (Recombinant Human Activated Protein C, rhAPC) in the Treatment of Severe Sepsis Induced by Graft Pancreatitis After Simultaneous Pancreas and Kidney Transplantation: A Case Report

We present our experience with recombinant human activated protein C (rhAPC) to treat a 40-year-old preemptive simultaneous pancreas-kidney transplant (spktx) recipient who developed septic shock due to graft pancreatitis. We diagnosed intra-abdominal septic complications with septicemia induced by multiple pathogens and cardiopulmonary insufficiency. Until the 59th posttransplant day, 21 peritoneal lavages were performed to treat peritonitis and intra-abdominal abscesses. On the 53rd day when septic shock was diagnosed, rhAPC was administered, after which the patient improved, vasoconstrictive agents were reduced, and respiratory insufficiency resolved. The Physiologic and Operative Severity Score for enumeration of Mortality and Morbidity (POSSUM) scale showed a decrease in predicted mortality from 93% to 17% on day 7 after rhAPC initiation. The patient was discharged at 128 days after spktx with good function of both grafts. Administration of rhAPC limited systemic inflammatory response syndrome (SIRS) and may be considered when faced with the dilemma of stopping immunosuppression to save a recipient's life but at the cost of rejection of a functioning graft.

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

OBJECTIVE

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

DESIGN

Multiple-center, randomized controlled study.

SETTING

Multiple hospitals.

PATIENTS

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

INTERVENTIONS

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

MEASUREMENTS AND MAIN RESULTS

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

CONCLUSIONS

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

Noninvasive positive pressure ventilation in patients with acute exacerbations of COPD and varying levels of consciousness

STUDY OBJECTIVES

A severely altered level of consciousness (ALC) has been considered a contraindication to noninvasive positive pressure ventilation (NPPV). We compared the clinical outcome of patients with acute respiratory failure (ARF) due to COPD exacerbations and different degrees of ALC.

DESIGN

A 5-year case-control study with a prospective data collection.

SETTING

Respiratory Monitoring Unit.

PATIENTS

Eighty of 153 consecutive COPD patients requiring NPPV for ARF were divided into four groups, which were carefully matched for the main physiologic variables, according to the level of consciousness assessed with the Kelly-Matthay Score, in which 1 is normal (control subjects) and 6 is severely impaired.

MEASUREMENT AND RESULTS

Changes from baseline in arterial blood gas (ABG) levels and Kelly score, the rate and causes of NPPV failure, the rate of nosocomial pneumonia, and the 90-day mortality rate were compared. NPPV significantly improved ABG levels and Kelly score in all groups after 1 to 2 h. NPPV failure (Kelly score 1 = 15%; Kelly score 2 = 25%; Kelly score 3 = 30%; Kelly score > 3 = 45%) and 90-day mortality rate (Kelly score 1 = 20%; Kelly score 2 = 35%; Kelly score 3 = 35%; Kelly score > 3 = 50%) significantly increased with the worsening of the level of consciousness. Using a multivariate analysis, the acute nonrespiratory component of the acute physiology and chronic health evaluation (APACHE) III score, and baseline pH independently predicted baseline Kelly score. After 1 to 2 h of NPPV, changes in the Kelly score were associated with those in pH. No correlation was found with Pa(CO2).

CONCLUSIONS

This study confirms that NPPV may be successfully applied to patients experiencing COPD exacerbations with milder ALCs, whereas the rate of failure in patients with severely ALCs (ie, Kelly score > 3) is higher, even though better than expected, so that an initial and cautious attempt with NPPV may be performed even in this latter group. Changes in the level of consciousness induced by NPPV are not correlated with those in Pa(CO2).

Predictive factors for the success of noninvasive mask ventilation in infants and children with acute respiratory failure

OBJECTIVE

Noninvasive mask ventilation (NIV) is a treatment option in acute respiratory failure in adults. This study was performed to determine prognostic variables for the success of NIV in a group of infants and children with respiratory failure for a wide range of reasons.

DESIGN

Prospective, clinical study.

SETTING

Multidisciplinary, neonatal-pediatric intensive care unit of a university teaching hospital.

METHODS

Descriptive study of infants and children <or=16 yrs of age with acute respiratory failure requiring assisted ventilation. During 2002-2003, patients with hypoxemic or hyper-carbic respiratory failure, signs of respiratory distress, and described by the attending critical care physician as likely to require intubation, were eligible to receive mask ventilation as an alternative means of respiratory support. Patients were not selected for their underlying disease contributing to the respiratory problems. Depending on whether they failed NIV and had to be intubated, the children were assigned to nonresponders or responders groups. The two groups were compared regarding physiologic variables prospectively evaluated before NIV and at 1, 8, 24, and 48 hrs of NIV.

RESULTS

A total of 42 patients were included. Their median age was 2.45 yrs (range, 0.01-18 yrs). Twenty-one patients required mask ventilation only with continuous positive airway pressure and 21 with biphasic positive airway pressure. In both responders' and nonresponders' blood gas results, heart rate and respiratory rate improved significantly after initiation of NIV (p<.0001). The courses of these variables did not differentiate between the two groups. The overall success rate of NIV was 57%. After 1 hr of NIV, there was a significantly higher Fio2 in patients who failed NIV than in responders. An Fio2 of >80% after 1 hr of NIV predicted nonresponse with a sensitivity of 56%, specificity of 83%, and positive and negative predictive value of 71%.

CONCLUSION

NIV can be successfully applied to infants and children with acute respiratory failure in the setting of a pediatric intensive care unit. The level of Fio2 after 1 hr of NIV may be a predictive factor for the treatment success.

Effectiveness of mask and helmet interfaces to deliver noninvasive ventilation in a human model of resistive breathing

The helmet, a transparent latex-free polyvinyl chloride cylinder linked by a metallic ring to a soft collar that seals the helmet around the neck, has been recently proposed as an effective alternative to conventional face mask to deliver pressure support ventilation (PSV) during noninvasive ventilation in patients with acute respiratory failure. We tested the hypothesis that mechanical characteristics of the helmet (large internal volume and high compliance) might impair patient-ventilator interactions compared with standard face mask. Breathing pattern, CO2 clearance, indexes of inspiratory muscle effort and patient-ventilator asynchrony, and dyspnea were measured at different levels of PSV delivered by face mask and helmet in six healthy volunteers before (load-off) and after (load-on) application of a linear resistor. During load-off, no differences in breathing pattern and inspiratory muscle effort were found. During load-on, the use of helmet to deliver pressure support increased inspiratory muscle effort and patient-ventilator asynchrony, worsened CO2 clearance, and increased dyspnea compared with standard face mask. Autocycled breaths accounted for 12 and 25% of the total minute ventilation and for 10 and 23% of the total inspiratory muscle effort during mask and helmet PSV, respectively. We conclude that PSV delivered by helmet interface is less effective in unloading inspiratory muscles compared with PSV delivered by standard face mask. Other ventilatory assist modes should be tested to exploit to the most the potential benefits offered by the helmet.

Early and late failure of noninvasive ventilation in chronic obstructive pulmonary disease with acute exacerbation

BACKGROUND

Despite recent encouraging results, the use of noninvasive ventilation (NIV) in the management of acute exacerbations in chronic obstructive pulmonary disease (COPD), complicated by acute respiratory failure (ARF), is not always successful. Failure of NIV may require an immediate intubation after a few hours (usually 1-3) of ventilation ('early failure') or may result in clinical deterioration (one or more days later) after an initial improvement of blood gas tension and general conditions ('late failure').

MATERIALS AND METHODS

We enrolled 122 patients affected by COPD complicated by ARF, and treated with NIV. The schedule of NIV provided sessions of 2-6 h twice daily.

RESULTS

Ninety-nine (81%) patients showed a progressive improvement of the clinical parameters and were discharged. Among the remaining 23 patients, 13 had an early failure and 10 had a late failure. In the 'success' group and 'late failure' groups we found after an increase of pH 2 h of NIV (from 7.31 +/- 0.05 to 7.38 +/- 0.04 P < 0.001 and from 7.29 +/- 0.03 to 7.36 +/- 0.02 P < 0.001, respectively) and a decrease of PaCO2 (from 80.93 +/- 9.79 to 66.48 +/- 5.95 P < 0.001 and from 85.96 +/- 10.77 to 76.41 +/- 11.02 P < 0.001, respectively). After 2 h of NIV in the 'late failure' group there were no significant changes in terms of pH (from 7.20 +/- 0.10 to 7.28 +/- 0.06) nor PaCO2 (from 92.86 +/- 35.49 to 93.68 +/- 23.68). The 'early failure' group had different characteristics and, owing to more severe conditions, the value of pH, of Glasgow Coma Score, and Apache II Score were the best predictors of the failure; while, among the complications on admission, metabolic alterations were the only independently significant predictor.

CONCLUSIONS

Our study confirms that NIV may be useful to avoid intubation in approximately 80% of patients with COPD complicated by moderate-severe hypercapnic respiratory failure.

Noninvasive Positive-Pressure Ventilation To Treat Hypercapnic Coma Secondary to Respiratory Failure

INTRODUCTION

Hypercapnic coma secondary to acute respiratory failure (ARF) is considered to be a contraindication to the use of treatment with noninvasive positive-pressure ventilation (NPPV). However, intubation exposes these patients to the risk of complications such as nosocomial pneumonia, sepsis, and even death.

PATIENTS AND METHODS

We performed a prospective, open, noncontrolled study to assess the outcomes of NPPV therapy in patients with a Glasgow coma scale (GCS) score of </= 8 points due to ARF. The primary goal of the study was to determine the success of NPPV therapy (defined as a response to therapy allowing the patient to avoid endotracheal intubation, and to survive a stay in the ICU and at least 24 h on a medical ward) in patients with hypercapnic coma, compared to those who started NPPV therapy while awake. The secondary goal of the study was to identify the variables that can predict a failure of NPPV therapy in these patients.

RESULTS

A total of 76 coma patients (80%) responded to NPPV therapy, and 605 patients with GCS scores > 8 responded to therapy (70%; p = 0.04). A total of 25 coma patients died in the hospital (26.3%), and 287 noncoma patients died in the hospital (33.2%; p = 0.17). The variables related to the success of NPPV therapy were GCS score 1 h posttherapy (odds ratio [OR], 2.32; 95% confidence interval [CI], 1.53 to 3.53) and higher levels of multiorgan dysfunction, as measured by the maximum sequential organ failure assessment index score reached during NPPV therapy (OR, 0.72; 95% CI, 0.55 to 0.92).

CONCLUSIONS

We concluded that selected patients with hypercapnic coma secondary to ARF can be treated as successfully with NPPV as awake patients with ARF.

Acute respiratory failure in the cancer patient: the role of non-invasive mechanical ventilation

The most common cause of ICU admission in patients affected by a hematologic or solid cancer is acute respiratory failure, often associated with a respiratory infection. The prognosis of these critically ill patients is disappointingly low especially if they require endotracheal intubation. In the last 10 years, non-invasive mechanical ventilation (NIV), delivered through a face or nose mask, has been increasingly used as an alternative to invasive ventilation. There is good evidence that, compared to the standard medical therapy alone or with invasive mechanical ventilation, NIV may improve survival and reduce the rate of infectious complications in patients affected by hematologic cancers. Patients with a solid tumor and "reversible" acute respiratory failure are also likely to benefit from NIV, while the use of NIV in palliative care of terminally ill patients still needs to be elucidated. The success of NIV is strictly dependent on its "early" use and on the experience of the staff involved.

The prognosis of acute respiratory failure in critically ill cancer patients

Acute respiratory failure (ARF) in patients with cancer is frequently a fatal event. To identify factors associated with survival of cancer patients admitted to an intensive care unit (ICU) for ARF, we conducted a prospective 5-year observational study in a medical ICU in a teaching hospital in Paris, France. The patients were 203 cancer patients with ARF mainly due to infectious pneumonia (58%), but also noninfectious pneumonia (9%), congestive heart failure (12%), and no identifiable cause (21%). We measured clinical characteristics and ICU and hospital mortality rates.ICU mortality was 44.8% and hospital mortality was 47.8%. Noninvasive mechanical ventilation was used in 79 (39%) patients and conventional mechanical ventilation in 114 (56%), the mortality rates being 48.1% and 75.4%, respectively. Among the 14 patients with late noninvasive mechanical ventilation failure (>48 hours), only 1 survived. The mortality rate was 100% in the 19 noncardiac patients in whom conventional mechanical ventilation was started after 72 hours. By multivariable analysis, factors associated with increased mortality were documented invasive aspergillosis (odds ratio [OR], 2.13; 95% confidence intervals [CI], 1.05-14.74), no definite diagnosis (OR, 3.85; 95% CI, 1.26-11.70), vasopressors (OR, 3.19; 95% CI, 1.28-7.95), first-line conventional mechanical ventilation (OR, 8.75; 95% CI, 2.35-35.24), conventional mechanical ventilation after noninvasive mechanical ventilation failure (OR, 17.46; 95% CI, 5.04-60.52), and late noninvasive mechanical ventilation failure (OR, 10.64; 95% CI, 1.05-107.83). Hospital mortality was lower in patients with cardiac pulmonary edema (OR, 0.16; 95% CI, 0.03-0.72). Survival gains achieved in critically ill cancer patients in recent years extend to patients requiring ventilatory assistance. The impact of conventional mechanical ventilation on survival depends on the time from ICU admission to conventional mechanical ventilation and on the patient's response to noninvasive mechanical ventilation.

Co-morbidity and acute decompensations of COPD requiring non-invasive positive-pressure ventilation

OBJECTIVE

To assess the prevalence and the impact of chronic and/or acute non-respiratory co-morbidity on short and longer-term outcome of non-invasive positive pressure ventilation (NIPPV) in acute decompensations of chronic obstructive pulmonary disease (COPD) with acute hypercapnic respiratory failure (AHRF).

DESIGN AND SETTING

An observational study in a three-bed respiratory monitoring unit in a respiratory ward of a non-university hospital.

PATIENTS

We grouped 120 consecutive COPD patients requiring NIPPV for AHRF (pH 7.28+/-0.05, PaO2/FIO2 ratio 192+/-63, PaCO2 78.3+/-12.3 mmHg) according to whether NIPPV succeeded (n=98) or failed (n=22) in avoiding the need for endotracheal intubation and whether alive (n=77) or dead (n=42) at 6 months.

MEASUREMENTS AND RESULTS

The prevalence of chronic and acute co-morbidity was, respectively, 20% and 41.7%; most of the cases were cardiovascular. In-hospital NIPPV failure was greater in patients with than in those without chronic (33.3% vs. 14.6%) or acute co-morbidity (32% vs. 8.6%). Six-month mortality was worse in patients with than in those without chronic (54.2% vs. 30.5%) or more than one acute co-morbidity (66.7% vs. 30.8%). Multiple regression analysis predicted in-hospital NIPPV failure by acute co-morbidity and forced expiratory volume in 1 s, while death at 6 months was predicted by having more than one acute co-morbidity, non-cardiovascular chronic co-morbidity and Activities of Daily Living score.

CONCLUSIONS

Chronic and acute co-morbidities are common in COPD patients with AHRF needing NIPPV and their presence influences short and longer-term outcome.

Noninvasive ventilation in patients with acute hypercapnic exacerbation of chronic obstructive pulmonary disease who refused endotracheal intubation

OBJECTIVE

To determine the long-term outcome of noninvasive ventilation in chronic obstructive pulmonary disease patients who refused intubation for acute hypercapnic respiratory failure.

DESIGN

Prospective, observational study.

SETTING

Noninvasive ventilation unit in an acute regional hospital in Hong Kong.

METHODS

The study recruited 37 chronic obstructive pulmonary disease patients who had the do-not-intubate code and developed acute hypercapnic respiratory failure. They were offered noninvasive ventilation, and their long-term outcomes were followed. Survival and event-free survival (an event is death or recurrent acute hypercapnic respiratory failure) were analyzed by survival analysis. Their disease profile and outcome were compared with another 43 chronic obstructive pulmonary disease patients without the do-not-intubate codes, who had acute hypercapnic respiratory failure and received noninvasive ventilation during the study period (usual care group).

RESULTS

Patients in the do-not-intubate group were significantly older (p =.029), had worse dyspnea score (p <.001), worse Katz Activities of Daily Living score (p <.001), worse comorbidity score (p =.024), worse Acute Physiology and Chronic Health Evaluation II score (p =.032), lower hemoglobin (p =.001), and longer stay in the hospital during the past year (p =.001) than patients who received usual care. In the do-not-intubate group, the median survival was 179 days, and 1-yr actuarial survival was 29.7%; in the usual care group, the median survival was not reached during follow-up, and 1-yr actuarial survival was 65.1% (p <.0001). In the do-not-intubate group, the median event-free survival was 102 days, and 1-yr event-free survival was 16.2%; in the usual care group, median event-free survival was 292 days, and 1-yr event-free survival was 46.5% (p =.0004).

CONCLUSIONS

A 1-yr survival of about 30% was recorded in chronic obstructive pulmonary disease patients with the do-not-intubate code who developed acute hypercapnic respiratory failure requiring noninvasive ventilation. The majority of survivors developed another life-threatening event in the following year. Information generated from this study is important to physicians and chronic obstructive pulmonary disease patients when they are considering using noninvasive ventilation as a last resort.

Non-invasive negative and positive pressure ventilation in the treatment of acute on chronic respiratory failure

OBJECTIVE

To investigate in clinical practice the role of non-invasive mechanical ventilation in the treatment of acute respiratory failure on chronic respiratory disorders.

DESIGN

An 18 months prospective cohort study.

SETTING

A specialised respiratory intensive care unit in a university-affiliated hospital.

PATIENTS

A total of 258 consecutive patients with acute respiratory failure on chronic respiratory disorders.

INTERVENTIONS

Criteria for starting non-invasive mechanical ventilation and for endotracheal intubation were predefined. Non-invasive mechanical ventilation was provided by positive pressure (NPPV) ventilators or iron lung (NPV).

RESULTS

The main characteristics of patients (70% with chronic obstructive pulmonary disease) on admission were (mean, SD or median, 25th-75th centiles): pH 7.29 (0.07), PaCO(2) 83 mm Hg (19), PaO(2)/FiO(2) 198 (77), APACHE II score 19 (15-24). Among the 258 patients, 200 (77%) were treated exclusively with non-invasive mechanical ventilation (40% with NPV, 23% with NPPV, and 14% with the sequential use of both), and 35 (14%) with invasive mechanical ventilation. In patients in whom NPV or NPPV failed, the sequential use of the alternative non-invasive ventilatory technique allowed a significant reduction in the failure of non-invasive mechanical ventilation (from 23.4 to 8.8%, p=0.002, and from 25.3 to 5%, p=0.0001, respectively). In patients as a whole, the hospital mortality (21%) was lower than that estimated by APACHE II score (28%).

CONCLUSIONS

Using NPV and NPPV it was possible in clinical practice to avoid endotracheal intubation in the large majority of unselected patients with acute respiratory failure on chronic respiratory disorders needing ventilatory support. The sequential use of both modalities may increase further the effectiveness of non-invasive mechanical ventilation.