Non-invasive ventilation in acute exacerbations of chronic obstructive pulmonary disease: long term survival and predictors of in-hospital outcome

Factores predictivos de un ingreso corto en pacientes con enfermedad pulmonar obstructiva crónica agudizada

BACKGROUND AND OBJECTIVE

We intended to identify the factors predicting a short length of stay in patients with chronic obstructive pulmonary disease (COPD) and acute exacerbations in order to select those who are tributary to be admitted in a short stay unit.

PATIENTS AND METHOD

Several clinical and biochemical characteristics were compared in a group of patients with COPD admitted in a short stay unit during an acute exacerbation, classified as lasting 4 days or > 4 days of hospital stay.

RESULTS

A comorbidity index of 2 [1-2] vs 3 [2-3.5], a number of breaths per minute of 29.0 (6.5) vs 33.6 (6.8) and a pCO2 value on admission of 39.1 (5.3) vs 50.7 (12.0) mmHg were factors independently associated with a shorter stay (p < 0.001 in all).

CONCLUSIONS

Some clinical characteristics of COPD patients are predictive of a short length of stay during acute exacerbations.

Noninvasive ventilation in hypercapnic acute respiratory failure due to chronic obstructive pulmonary disease vs. other conditions: effectiveness and predictors of failure

OBJECTIVE

This study compared the effectiveness of noninvasive ventilation (NIV) and the risk factors for NIV failure in hypercapnic acute respiratory failure (ARF) due to chronic obstructive pulmonary disease (COPD) vs. non-COPD conditions.

DESIGN AND SETTING

Prospective cohort study in the medical intensive care unit of a university hospital.

PATIENTS AND PARTICIPANTS

111 patients with hypercapnic ARF, 43 of whom had COPD exacerbations and 68 other conditions. Baseline characteristics of the two groups were similar.

MEASUREMENTS AND RESULTS

The risk of NIV failure, defined as the need for endotracheal intubation, was significantly lower in COPD than in other conditions (19% vs. 47%). High APACHE II score was an independent predictor of NIV failure in COPD (OR 5.38 per 5 points). The presence of pneumonia (OR 5.63), high APACHE II score (OR 2.59 per 5 points), rapid heart rate (OR 1.22 per 5 beats/min), and high PaCO(2) 1 h after NIV (OR 1.22 per 5 mmHg) were independent predictors of NIV failure in the non-COPD group. Failure of NIV independently predicted mortality (OR 10.53).

CONCLUSIONS

Noninvasive ventilation was more effective in preventing endotracheal intubation in hypercapnic ARF due to COPD than non-COPD conditions. High APACHE II score predicted NIV failure in both groups. Noninvasive ventilation was least effective in patients with hypercapnic ARF due to pneumonia.

Readmission rates and life threatening events in COPD survivors treated with non-invasive ventilation for acute hypercapnic respiratory failure

BACKGROUND

Non-invasive ventilation (NIV) has been shown to reduce intubation and in-hospital mortality in patients with chronic obstructive pulmonary disease (COPD) and acute hypercapnic respiratory failure (AHRF). However, little information exists on the outcomes following discharge. A study was undertaken to examine the rates of readmission, recurrent AHRF, and death following discharge and the risk factors associated with them.

METHODS

A cohort of COPD patients with AHRF who survived after treatment with NIV in a respiratory high dependency unit was prospectively followed from July 2001 to October 2002. The times to readmission, first recurrent AHRF, and death were recorded and analysed against potential risk factors collected during the index admission.

RESULTS

One hundred and ten patients (87 men) of mean (SD) age 73.2 (7.6) years survived AHRF after NIV during the study period. One year after discharge 79.9% had been readmitted, 63.3% had another life threatening event, and 49.1% had died. Survivors spent a median of 12% of the subsequent year in hospital. The number of days in hospital in the previous year (p = 0.016) and a low Katz score (p = 0.018) predicted early readmission; home oxygen use (p = 0.002), APACHE II score (p = 0.006), and a lower body mass index (p = 0.041) predicted early recurrent AHRF or death; the MRC dyspnoea score (p<0.001) predicted early death.

CONCLUSIONS

COPD patients with AHRF who survive following treatment with NIV have a high risk of readmission and life threatening events. Further studies are urgently needed to devise strategies to reduce readmission and life threatening events in this group of patients.

Management of severe COPD

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide, and the burden of the disorder will continue to increase over the next 20 years despite medical intervention. Apart from smoking cessation, no approach or agent affects the rate of decline in lung function and progression of the disease. Especially in the later phase, COPD is a multicomponent disorder, and various integrated intervention strategies are needed as part of the optimum management programme. This seminar describes largely non-pharmacological interventions aimed at improving health status and function of disabled patients. Exacerbations become progressively more troublesome as baseline lung function declines, commonly necessitating hospital admission and associated with the development of acute respiratory failure.

Effects of Mechanical Insufflation-Exsufflation on Respiratory Parameters for Patients With Chronic Airway Secretion Encumbrance

STUDY OBJECTIVES

To analyze the physiologic effects and tolerance of mechanical insufflation-exsufflation (MI-E) for patients with chronic ventilatory failure of various etiologies.

DESIGN

Prospective clinical trial.

SETTING

Rehabilitation unit of a university hospital.

PATIENTS OR PARTICIPANTS

Thirteen patients with amyotrophic lateral sclerosis (ALS), 9 patients with severe COPD, and 7 patients with other neuromuscular disorders (oNMDs) with chronic airway secretion encumbrance and decreases in oxyhemoglobin saturation (Spo(2)).

INTERVENTIONS

Pressures of MI-E of 15 cm H(2)O, 30 cm H(2)O, and 40 cm H(2)O were cycled to each patient, with 3 s for insufflation and 4 s for exsufflation. One application was six cycles at each pressure for a total of three applications.

MEASUREMENTS AND RESULTS

We continuously evaluated respiratory inductance plethysmography (RIP) and Spo(2) during every application. Peak cough flow (PCF) and dyspnea (Borg Scale) were also measured before the first and after the last application. The technique was well tolerated in all patient groups. Median Spo(2) improved significantly (p < 0.005) in all patient groups. Median PCF improved significantly (p < 0.005) in the ALS and oNMD groups from 170 to 200 L/min and from 180 to 220 L/min, respectively, and dyspnea improved significantly in the patients with oNMDs and patients with COPD from 3 to 1 and from 2 to 0.75, respectively. Breathing pattern characteristics (RIP) did not deteriorate after MI-E in any patient groups. Inspiratory flow limitation significantly decreased at the highest MI-E pressures for the ALS group.

CONCLUSIONS

Our results confirm good tolerance and physiologic improvement in patients with restrictive disease and in patients with obstructive disease, suggesting that MI-E may be a potential complement to noninvasive ventilation for a wide variety of patient groups.

An empirical analysis of the decision-making of limiting life-sustaining treatment for patients with advanced chronic obstructive pulmonary disease in Hong Kong, China

OBJECTIVES

To understand the prognostic and quality-of-life considerations surrounding life-sustaining treatment decisions for patients with advanced chronic obstructive pulmonary disease (COPD) in Hong Kong China.

METHODS

A documentary review of 49 COPD patients and 19 patient case studies from the medical departments of 2 hospitals were undertaken to examine the practices of DNI decision-making (do not perform mechanical ventilation and cardiopulmonary resuscitation). Statistical, event, and thematic analyses were conducted to delineate the prognostic and quality-of-life factors that shaped the not for intubation and mechanical ventilation (DNI) decisions.

RESULTS

Three major treatment-limiting decision-making patterns existed in practice: 1) Patient-initiated and shared decision-making with physician (n = 14); 2) Physician-initiated and shared decision-making with the patient/family members (n = 24); and 3) Physician-initiated DNI decision-making with patient family, but without patient participation due to mental incapacity (n = 11). Prognostic considerations include physiological parameters, performance status, concomitant diseases, therapeutic regimens, and the utilization of medical services. Three major themes were delineated regarding the way in which the patients evaluated their life quality in the context of DNI status. They are prognostic awareness, illness burdens, and existential concerns.

DISCUSSION

A decision-making framework used by patients/families/physicians to limit life-sustaining treatments in patients with advanced COPD is delineated. Observations regarding how treatment limiting decision-making for patients with advanced chronic illnesses can be improved in Hong Kong are discussed.

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.

Clinical review: Noninvasive ventilation in the clinical setting--experience from the past 10 years

This brief review analyses the progress of noninvasive ventilation (NIV) over the last decade. NIV has gained the dignity of first line intervention for acute exacerbation of chronic obstructive pulmonary disease, assuring reduction of the intubation rate, rate of infection and mortality. Despite positive results, NIV still remains controversial as a treatment for acute hypoxemic respiratory failure, largely due to the different pathophysiology of hypoxemia. The infection rate reduction effect achieved by NIV application is crucial for immunocompromised patients for whom the endotracheal intubation represents a high risk. Improvements in skills acquired with experience over time progressively allowed successful treatment of more severe patients.

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.

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 ventilation for acute respiratory disease

Non-invasive ventilation (NIV) has been shown to be effective in acute respiratory failure of various aetiologies in different health care systems and ward settings. It should be seen as complementary to invasive ventilation and primarily a means of preventing some patients from deteriorating to the point at which intubation is needed. Generally it is best initiated early before assisted ventilation is mandatory, although it has been shown to be effective even in very sick patients. Important benefits include the avoidance of endotracheal-tube-associated infections, which carry an important morbidity and mortality, and a reduction in health care costs. The most important ingredient for an acute NIV service is a well-trained enthusiastic ward team.

Non-invasive positive pressure ventilation for treatment of respiratory failure due to exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Non-invasive positive pressure ventilation (NPPV) is being used increasingly in the management of patients admitted to hospital with acute respiratory failure secondary to an exacerbation of chronic obstructive pulmonary disease (COPD).

OBJECTIVES

To determine the efficacy of NPPV in the management of patients with respiratory failure due to an acute exacerbation of COPD.

SEARCH STRATEGY

An initial search was performed using the Cochrane Airways Group trials register and other relevant electronic databases. An updated search was conducted in September 2003 and another in April 2004.

SELECTION CRITERIA

Randomised controlled trials comparing NPPV plus usual medical care (UMC) versus UMC alone were selected. Trials needed to recruit adult patients admitted to hospital with respiratory failure due to an exacerbation of COPD and with PaCO2 > 6 kPa (45 mmHg).

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected articles for inclusion, evaluated methodological quality of the studies and abstracted the data.

MAIN RESULTS

Fourteen studies were included in the review. NPPV resulted in decreased mortality (Relative Risk 0.52; 95%CI 0.35 to 0.76), decreased need for intubation (RR 0.41; 95%CI 0.33 to 0.53), reduction in treatment failure (RR 0.48; 95%CI 0.37 to 0.63), rapid improvement within the first hour in pH (Weight Mean Difference 0.03; 95%CI 0.02 to 0.04), PaCO2 (WMD -0.40 kPa; 95%CI -0.78 to -0.03) and respiratory rate (WMD -3.08 bpm; 95%CI -4.26 to -1.89). In addition, complications associated with treatment (RR 0.38; 95%CI 0.24 to 0.60) and length of hospital stay (WMD -3.24 days; 95%CI -4.42 to -2.06) was also reduced in the NPPV group.

REVIEWERS' CONCLUSIONS

Data from good quality randomised controlled trials show benefit of NPPV as first line intervention as an adjunct therapy to usual medical care in all suitable patients for the management of respiratory failure secondary to an acute exacerbation of COPD. NPPV should be considered early in the course of respiratory failure and before severe acidosis ensues, as a means of reducing the likelihood of endotracheal intubation, treatment failure and mortality.

Non-invasive positive pressure ventilation for treatment of respiratory failure due to exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Non-invasive positive pressure ventilation (NPPV) is being used increasingly in the management of patients admitted to hospital with acute respiratory failure secondary to an exacerbation of chronic obstructive pulmonary disease (COPD).

OBJECTIVES

To determine the efficacy of NPPV in the management of patients with respiratory failure due to an acute exacerbation of COPD.

SEARCH STRATEGY

An initial search was performed using the Cochrane Airways Group trials register and other relevant electronic databases. An updated search was conducted in September 2003.

SELECTION CRITERIA

Randomised controlled trials comparing NPPV plus usual medical care (UMC) versus UMC alone were selected. Trials needed to recruit adult patients admitted to hospital with respiratory failure due to an exacerbation of COPD and with PaCO(2) > 6 kPa (45 mmHg).

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected articles for inclusion, evaluated methodological quality of the studies and abstracted the data.

MAIN RESULTS

Fourteen studies were included in the review. NPPV resulted in decreased mortality (Relative Risk 0.52; 95%CI 0.35, 0.76), decreased need for intubation (RR 0.41; 95%CI 0.33, 0.53), reduction in treatment failure (RR 0.48; 95%CI 0.37, 0.63), rapid improvement within the first hour in pH (Weight Mean Difference 0.03; 95%CI 0.02, 0.04), PaCO(2) (WMD -0.40 kPa; 95%CI -0.78, -0.03) and respiratory rate (WMD -3.08 bpm; 95%CI -4.26, -1.89). In addition, complications associated with treatment (RR 0.38; 95%CI 0.24, 0.60) and length of hospital stay (WMD -3.24 days; 95%CI -4.42, -2.06) was also reduced in the NPPV group.

REVIEWER'S CONCLUSIONS

Data from good quality randomised controlled trials show benefit of NPPV as first line intervention as an adjunct therapy to usual medical care in all suitable patients for the management of respiratory failure secondary to an acute exacerbation of COPD. NPPV should be considered early in the course of respiratory failure and before severe acidosis ensues, as a means of reducing the likelihood of endotracheal intubation, treatment failure and mortality.

Domiciliary non-invasive ventilation for recurrent acidotic exacerbations of COPD: an economic analysis

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) pose a significant burden to healthcare providers with frequent exacerbations necessitating hospital admission. Randomised controlled data exist supporting the use of acute non-invasive ventilation (NIV) in patients with exacerbations of COPD with mild to moderate acidosis. The use of NIV is also described in chronic stable COPD, with evidence suggesting a reduction in hospital admissions and general practitioner care. We present economic data on the impact of domiciliary NIV on the need for admission to hospital and its attendant costs.

METHODS

A cost and consequences analysis of domiciliary NIV based on a before and after case note audit was performed in patients with recurrent acidotic exacerbations of COPD who tolerated and responded well to NIV. The primary outcome measure was the total cost incurred per patient per year from the perspective of the acute hospital. Effectiveness outcomes were total days in hospital and in intensive care.

RESULTS

Thirteen patients were identified. Provision of a home NIV service resulted in a mean (95% CI) saving of pound sterling 8254 (pound sterling 4013 to pound sterling 12,495) (Euro 11,720; Euro 5698 to Euro 17,743) per patient per year. Total days in hospital fell from a mean (SD) of 78 (51) to 25 (25) (p=0.004), number of admissions from 5 (3) to 2 (2) (p=0.007), and ICU days fell from a total of 25 to 4 (p=0.24). Outpatient visits fell from a mean of 5 (3) to 4 (2) (p=0.14).

CONCLUSIONS

This study suggests that domiciliary NIV for a highly selected group of COPD patients with recurrent admissions requiring NIV is effective at reducing admissions and minimises costs from the perspective of the acute hospital. Such evidence is important in obtaining financial support for providing such a service.

Acute exacerbations in chronic obstructive pulmonary disease: current strategies with pharmacological therapy

In acute exacerbation of chronic obstructive pulmonary disease (AECOPD), short-acting inhaled bronchodilators, such as salbutamol (albuterol) and ipratropium bromide, have proven useful. In patients who are refractory to these agents, intravenous aminophylline should be considered. Corticosteroids should also be used, either in the outpatient or inpatient setting. The duration of corticosteroids should probably not exceed 2 weeks and the optimum dosage is yet to be determined. Antibacterials, especially in patients with purulent or increased sputum, should be used, guided by the local antibiogram of the key microbes. Controlled oxygen therapy improves outcome in hypoxaemic patients and arterial blood gases should be performed to ensure hypercarbia is not becoming excessive. Should patients be in distress despite the above measures or if there is acidaemia or hypercarbia, noninvasive positive pressure ventilation could be used to improve outcomes without resorting to invasive mechanical ventilation. Mucous-clearing drugs and chest physiotherapy have no proven beneficial role in AECOPD.

Chronic obstructive pulmonary disease * 9: management of ventilatory failure in COPD

The management of respiratory failure during acute exacerbations of COPD and during chronic stable COPD is reviewed and the role of non-invasive and invasive mechanical ventilation is discussed.

Treatment of chronic obstructive pulmonary disease in older patients: a practical guide

Chronic obstructive pulmonary disease (COPD) is a common disability, largely encountered in the elderly population, in whom it causes significant morbidity and mortality. The general perception of health professionals is that COPD is often a self-inflicted disorder affecting the more socio-economically disadvantaged segment of the population with significant comorbidity. COPD is the least funded in terms of research in relation to illness burden compared with other chronic diseases. However, recently published guidelines of both the British Thoracic Society and the Global Initiative for Chronic Obstructive Lung Disease have highlighted best management strategies both of chronic symptoms and acute exacerbations in this patient group. The chronic management of COPD should, like asthma, involve a stepwise approach with smoking cessation being pivotal for all severities of COPD, regardless of patient age. The mainstay of therapeutic treatment remains regular bronchodilators, both beta(2)-adrenoreceptor agonists and anticholinergic agents. Current evidence suggests that long-acting beta(2)-adrenoreceptor agonists such as salmeterol and the new long-acting anticholinergic agent tiotropium bromide are more efficacious than their shorter acting equivalents such as salbutamol and ipratropium bromide in terms of bronchodilation, improved well-being and a reduction in acute exacerbation rates. Additionally since they are taken once or twice daily compliance should be improved. The role of long-term inhaled corticosteroids in the chronic management of COPD is contentious. Only those patients with COPD who have been shown to respond to a formal corticosteroid trial, preferably with a 2-week course of oral corticosteroid, should receive long-term inhaled corticosteroids. In the management of acute exacerbations in acidotic patients nasal ventilation is the treatment of choice in addition to conventional treatment with bronchodilators and oral corticosteroids. Antibacterials need not be prescribed universally in all exacerbations of COPD. Pulmonary rehabilitation classes either individually or in groups have been shown to be beneficial in the management of patients with COPD and their use in secondary care is to be encouraged. Most treatment modalities do not improve pulmonary function in patients with severe COPD. Therefore, pulmonary function including spirometry should be used to make the diagnosis of COPD but not as a monitor of efficacy of treatment. Assessment of severity of COPD and improvement with treatment modalities is best done with dynamic exercise testing such as 6-minute walk tests and incremental shuttle walk tests or with the administration of disease-specific physical disability and quality-of-life questionnaires. Most COPD research does not specifically target the older COPD patients and these patients may merit special consideration for their optimum assessment and management.

Changes in the practice of non-invasive ventilation in treating COPD patients over 8 years

OBJECTIVE

We reviewed data of 208 episodes of acute respiratory failure due to chronic obstructive pulmonary disease treated by non-invasive ventilation (NIV) in our Respiratory Intensive Care Unit (RICU) from its opening in 1992 to 1999.

MATERIAL AND METHODS

We assessed whether the rate of NIV success, the severity of the disease, and the associated costs changed in this period during which the staff and the equipment did not change.

RESULTS

The failure rate was constant over the years (17.2% on average). The severity of the episodes of ARF, defined by pH and APACHE II at admission, worsened during the years. The statistical change point test allowed us to identify 1997 as the year of a significant change in the severity of admission pH and therefore to identify two different periods: 1992-1996 (mean pH = 7.25+/-0.07) and 1997-1999 (7.20+/-0.08; P<0.001). In this latter period the risk of failure for a patient with a pH <7.25 was threefold lower than in 1992-1996. In 1997-1999 an increasing number of episodes of ARF with a pH >7.28 were treated in the Medical Ward (20% vs 60%). This allowed a significant reduction of daily cost per patient treated with NIV (558+/-8 Euros vs 470+/-14 Euros, respectively; P<0.01).

CONCLUSIONS

We conclude that, over time, experience with NIV may progressively allow more severely ill patients to be treated without changing the rate of success. The daily cost of NIV per patient can be reduced by treating less severely ill patients outside the RICU.

[Noninvasive ventilation in the intensive care unit -- is it still negligible?]

Non-invasive positive pressure ventilation (NIPPV) has been discussed comprehensively in the last years, but usage of non-invasive ventilation in Intensive Care Units is rare. The reasons may be uncertainty in indications and difficulties in handling the masks and ventilators. In the last years the introduction of full face masks and respiratory helmets has made it possible to ventilate patients with unusual facial forms and to avoid problems of pressure necrosis. Software components designed for NIPPV are available for standard respirators. Indications for NIPPV (neuromuscular diseases, spinal abnormalities, chest wall malformations, COPD, cardiogenic pulmonary edema) have been ensured in clinical trials. No sufficient data are available for the application of NIPPV in weaning and respiratory failure following extubation. Indication for NIPPV becomes apparent when therapy starts in early stage with sufficient ventilation pressure. Compared to standard therapy, no reliable advantage has been seen for NIPPV in hypoxic hypercapnia respiratory failure except for malignant diseases. However, prophylactic use in patients with high risk might be conceivable. For these patients strict criteria of termination are required to avoid missing the time point for intubation. Gas exchange disturbances in advanced lung fibrosis, pneumonia and ARDS are not amenable to NIPPV. Contraindications for NIPPV are non-compliant patients, absence of cough- and pharyngeal reflexes as well as retention of secretions and malignant ventricular arrhythmia. Relative contraindications are catecholamine-dependent circulatory collapse and acute myocardial infarction, since sufficient data for NIPPV are missing.

Non-invasive ventilation and palliation: experience in a district general hospital and a review

Non-invasive ventilation (NIV) is increasingly being used in hospitals to treat respiratory failure. The use of NIV with palliative intent in a district general hospital is described and ten illustrative cases where NIV was used in an attempt to palliate symptoms or to 'buy time' are presented. The role of NIV in relieving symptoms in various conditions is reviewed and ethical aspects are considered. It is suggested that hospital palliative care teams will increasingly see patients treated by this technique as it becomes more widely used for exacerbations of chronic obstructive airways disease, for relief of breathlessness in the terminally ill and for buying time in patient management. Domiciliary teams will see increasing numbers of people with motor neurone disease and other conditions treated with NIV.

The pulmonary physician in critical care. 11: critical care management of respiratory failure resulting from COPD

Survival to hospital discharge of patients suffering exacerbations of COPD is better than other medical causes for ICU admission. Although non-invasive ventilation (NIV) may prevent progression to tracheal intubation, its failure in most cases should lead to a period of controlled mechanical ventilation aiming for early extubation, possibly supported by NIV and tracheostomy if this fails. A greater understanding of the physiological principles behind ventilatory support of patients with COPD should reduce patient-ventilator disharmony and avoid the excessive use of sedation. The risk of nosocomial infection increases with the length of time the patient remains in the ICU and commonly further prolongs the period of ventilator dependency. Weaning centres with an emphasis on general rehabilitation may offer the best support for such individuals.

Non-invasive positive pressure ventilation in patients with acute respiratory failure

Non-invasive positive pressure ventilation is an emerging modality in contemporary critical care practice. Perhaps the most widely utilized and familiar form of non-invasive positive pressure ventilation is mask continuous positive airway pressure. Other common modes include mask Bi-level positive airway pressure and mask pressure support ventilation. All feature the delivery of positive airway pressure via a mask (full-face, naso-oral or nasal), and a patient-controlled respiratory cycle. The physiological benefits of non-invasive positive pressure ventilation suggested by a number of studies include improved oxygenation, decreased work of breathing, improved ventilation and perfusion matching, decreased fatigue, and increased minute ventilation. The utilization of non-invasive positive pressure ventilation has now been reported for a variety of clinical indications. In most, randomized trials are lacking, and the benefits and preferred mode of non-invasive positive pressure ventilation are still to be elucidated. In general, in patients that are candidates for endotracheal intubation, non-invasive positive pressure ventilation should be used as a way to possibly avoid endotracheal intubation rather than as an alternative to endotracheal intubation. Whilst the benefit of non-invasive positive pressure ventilation appears to be established in patients with chronic obstructive airways disease with hypercapnic acute respiratory failure, one of the major unresolved issues is whether one modality is significantly better than the others. Unfortunately, the question of whether Bi-level positive airway pressure is better than continuous positive airway pressure in this clinical scenario has not been satisfactorily addressed in any large randomized and controlled clinical trial. Further, there is no 'gold standard' for predicting success with non-invasive positive pressure ventilation, although several studies have looked at this aspect.

[Non-invasive ventilation in patients with severe hypercapnic encephalopathy in a conventional hospital ward]

OBJECTIVE

To report our experience with non-invasive ventilation (NIV) at two levels of pressure (Bi-PAP) on a general respiratory medicine ward with patients in hypercapnic impaired consciousness and/or coma who had not previously been in an intensive care unit (ICU).

METHODS

This was a prospective study of 13 patients, mean age 81 years (65-96), treated with NIV through a face mask. Ten had chronic obstructive pulmonary disease, with a mean FEV1 in stable condition of 35.2 14.6%. Glasgow scores upon admission were >/= 7. Arterial gases were monitored until suspension of NIV.

RESULTS

After NIV for a mean 19 5 h/day in the first 48 hours and later of 6 1 h/day until a total of 74 9 h, 9 patients (69%) survived. The mean initial pH for these patients was 7.17 0.028 and the mean initial pCO2 was 101 9 mm Hg. In 7 cases (78%), coma was reversed in the first 48 h and a significant improvement in pH was observed in the 12-24 h analysis. Mean pH upon discharge was 7.44 0.013 and mean pCO2 was 54 2.8 mmHg. Four patients died, even though their initial or subsequent arterial gases at 12-24 h were not significantly different from those of the survivors.

CONCLUSION

NIV on a general respiratory medicine ward can offer an alternative to oro-tracheal intubation for patients with hypercapnic impaired consciousness and/or coma who do not meet the criteria for admission to the ICU.