Noninvasive Ventilation — Don't Push Too Hard
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《新英格兰医药杂志》
Noninvasive mechanical ventilation has been used increasingly over the past decade in an effort to avoid endotracheal intubation and to accelerate the discontinuation of mechanical ventilation. Noninvasive ventilation as adjunctive therapy can be applied before intubation or after extubation (Figure 1). The literature indicates that in both settings, outcomes in patients with chronic obstructive pulmonary disease (COPD) or cardiogenic pulmonary edema are successful.1 Randomized, controlled trials also provide outcome data supporting the use of noninvasive ventilation to obviate the need for endotracheal intubation in immunosuppressed patients who have bilateral infiltrates and patients who are recovering from lung resection.1
Figure 1. Suggested Application of Noninvasive Ventilation.
COPD denotes chronic obstructive pulmonary disease.
Noninvasive ventilation has been used in the care of other types of patients in the hope of avoiding intubation or reintubation. In this issue of the Journal, Esteban et al.2 report the results of their study of the use of noninvasive ventilation in patients with acute respiratory failure after extubation. Noninvasive ventilation did not result in reduced rates of reintubation, and delays in reintubation after the development of acute respiratory failure actually correlated with worsened survival rates. The latter finding is a matter of great concern as clinicians explore further applications of noninvasive ventilation.
When noninvasive ventilation is effective, clinical status generally improves within two hours after its application. Such changes can include reductions in the respiratory rate and the use of accessory muscles and improvements in pH, arterial carbon dioxide tension, and arterial oxygen tension. Given the data presented by Esteban et al.,2 a two-hour trial accompanied by quantitative assessment in patients in whom noninvasive ventilation is initiated is advisable. Furthermore, our interpretation of the data suggests that this approach is best limited to populations of patients in whom success has been demonstrated.
Randomized, controlled trials involving patients with COPD have demonstrated reductions in intubation rates as a result of the application of noninvasive ventilation during acute hypercapnic respiratory failure.1,3,4,5 Reductions in nosocomial complications and even in mortality have been recorded. Some studies have also found that patients with COPD who were randomly assigned to noninvasive ventilation had a shorter stay in the intensive care unit. Noninvasive ventilation has been applied to very ill, immunosuppressed patients with bilateral infiltrates, and reductions in intubation rates and mortality have been observed.6 Similarly, it has been observed that patients receiving noninvasive ventilation after thoracic surgery appear to benefit from this strategy, when outcomes are assessed in terms of intubation rates.1
Noninvasive ventilation has proved to be beneficial in patients with cardiogenic pulmonary edema in randomized, controlled trials.1,7,8 However, it is not clear whether continuous positive airway pressure alone results in maximal gain or whether bilevel positive airway pressure provides additional benefit. In one small study, the latter technique was associated with more myocardial infarctions than the former.8 Clearly, continuous positive airway pressure is of benefit, and in our opinion, clinicians should choose continuous positive airway pressure until further data indicate an advantage in association with the bilevel technique.
A recent study by Ferrer et al.9 suggests that extubation followed immediately by the application of noninvasive ventilation may confer significant benefit in patients who are initially intubated for acute respiratory failure and who meet established criteria for the discontinuation of mechanical ventilation but who have had unsuccessful trials of spontaneous breathing on three successive days. Reductions in ventilation time and in mortality were noted. In that study, two thirds of the patients had COPD or cardiogenic pulmonary edema. Nava et al. randomly assigned patients with COPD who were intubated for 48 hours to extubation and noninvasive ventilation or to continued invasive ventilation and conventional discontinuation after an unsuccessful initial spontaneous-breathing trial.10 The study demonstrated improved outcomes as measured by the percentage of patients in whom assisted ventilation could be discontinued, the duration of assisted ventilation, survival, the length of stay in the intensive care unit, and the incidence of ventilator-associated pneumonia. Currently, there are no data supporting the use of noninvasive ventilation to facilitate the discontinuation of assisted ventilation, other than in patients with COPD or cardiogenic pulmonary edema.
The use of noninvasive ventilation in patients in whom acute respiratory distress develops after extubation, and not as an immediately applied adjunct to extubation, has also been examined. A historical case–control study by Hilbert et al. showed a reduction in the rate of reintubation in patients with COPD.11 A recent randomized, controlled trial by Keenan et al. did not show a benefit in association with the application of noninvasive ventilation.12 However, less than 10 percent of the patients assigned to noninvasive ventilation had a diagnosis of COPD. Cardiac disease was the predominant diagnosis, but it is unclear whether cardiogenic pulmonary edema was present or not.
In the trial by Esteban et al.,2 the use of noninvasive ventilation failed to prove beneficial in patients in whom respiratory failure developed within 48 hours after extubation. These authors randomly assigned patients to medical treatment or noninvasive ventilation and compared outcomes. They found that reintubation rates were equal in the two groups but that mortality was higher in the noninvasive-ventilation group. The percentages of patients with COPD (12 percent) or cardiogenic pulmonary edema (7 percent) in the noninvasive-ventilation group were low but not statistically different from those in the control group. Mortality rates were higher in the noninvasive-ventilation group, predominantly because the mortality rate among the patients in that group who required reintubation was higher than that of the patients in the control group who required reintubation. The time to reintubation was considerably longer in the noninvasive-ventilation group than in the control group (median, 12 hours vs. 2 hours 30 minutes).
In our opinion, given the absence of supportive data, noninvasive ventilation when used to prevent reintubation should be limited to patients with COPD and perhaps those with cardiogenic pulmonary edema. Surveillance to determine which patients require early reintubation, if indicated, appears essential, given the results of the study by Esteban et al.
Successful noninvasive-ventilation strategies require a program that includes the availability of well-trained staff, careful selection of patients, and attention to patients' responses to noninvasive ventilation. Noninvasive ventilation appears best suited to patients with COPD, those with cardiogenic pulmonary edema, those who have just undergone lung surgery, and those who are immunosuppressed and have bilateral infiltrates. Some data do support the use of noninvasive ventilation in patients who have acute exacerbations of asthma, pneumonia, hypoxic respiratory failure, trauma, or the acute respiratory distress syndrome and patients who have restrictive lung disease and are acutely ill.1,13 However, because the evidence is insufficient at this time, the use of noninvasive ventilation in these populations cannot be uniformly recommended. Additional selection criteria include moderate-to-severe respiratory distress, tachypnea, accessory-muscle use, asynchronous chest–abdominal muscle use, hypercapnia, and moderate acidosis.
Factors favoring the successful application of noninvasive ventilation are a small volume of respiratory secretions; intact dentition; low scores on the Acute Physiology and Chronic Health Evaluation II; synchronous breathing; a good initial response in terms of pH, arterial carbon dioxide tension, and respiratory rate; and the ability to protect the airway.1 Many believe that with patients who have acute respiratory distress there is a fairly narrow window of opportunity for the use of noninvasive ventilation; they need to be sick enough for intervention but not sick enough to require immediate intubation. The initial six-to-eight-hour period of noninvasive ventilation is resource-intensive, and failure to intubate a patient who does not have a response is associated with increased mortality.
The article by Esteban et al.2 provides a valuable lesson for all practicing clinicians. The application of noninvasive ventilation is not without peril. Although the report addresses patients in whom respiratory failure develops after extubation, the lessons learned probably apply to all patients receiving noninvasive ventilation. A high level of vigilance is required to identify those who do not have a response, and adherence to defined selection and exclusion criteria should be maintained. Noninvasive ventilation is clearly developing its own place in the list of medical options for the treatment of acute respiratory failure; however, as with all treatments, there appear to be important risks that come with the benefits.
Source Information
From the Division of Pulmonary and Critical Care Medicine, University of Virginia, Charlottesville (J.D.T.); and the Division of Allergy, Pulmonary, and Critical Care Medicine, Vanderbilt University, Nashville (G.R.B.).
References
Liesching T, Kwok H, Hill NS. Acute applications of noninvasive positive pressure ventilation. Chest 2003;124:699-713.
Esteban A, Frutos-Vivar F, Niall D, et al. Noninvasive positive-pressure ventilation for respiratory failure after extubation. N Engl J Med 2004;350:2452-2460.
Brochard L, Mancebo J, Wysocki M, et al. Noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease. N Engl J Med 1995;333:817-822.
Plant PK, Owen JL, Elliott MW. Early use of non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease on general respiratory wards: a multicentre randomised controlled trial. Lancet 2000;355:1931-1935.
Keenan SP, Sinuff T, Cook DJ, Hill NS. Which patients with acute exacerbation of chronic obstructive pulmonary disease benefit from noninvasive positive-pressure ventilation? A systematic review of the literature. Ann Intern Med 2003;138:861-870.
Hilbert G, Gruson D, Vargas F, et al. Noninvasive ventilation in immunosuppressed patients with pulmonary infiltrates, fever, and acute respiratory failure. N Engl J Med 2001;344:481-487.
Masip J, Betbese AJ, Paez J, et al. Non-invasive pressure support ventilation versus conventional oxygen therapy in acute cardiogenic pulmonary oedema: a randomised trial. Lancet 2000;356:2126-2132.
Mehta S, Jay GD, Woodward RH, et al. Randomized prospective trial of bilevel versus continuous positive airway pressure in acute pulmonary edema. Crit Care Med 1997;25:620-628.
Ferrer M, Esquinas A, Arancibia F, et al. Noninvasive ventilation during persistent weaning failure: a randomized controlled trial. Am J Respir Crit Care Med 2003;168:70-76.
Nava S, Ambrosino N, Clini E, et al. Noninvasive mechanical ventilation in the weaning of patients with respiratory failure due to chronic obstructive pulmonary disease: a randomized, controlled trial. Ann Intern Med 1998;128:721-728.
Hilbert G, Gruson D, Portel L, Gbikpi-Benissan G, Cardinaud JP. Noninvasive pressure support ventilation in COPD patients with postextubation hypercapnic respiratory insufficiency. Eur Respir J 1998;11:1349-1353.
Keenan SP, Powers C, McCormack DG, Block G. Noninvasive positive-pressure ventilation for postextubation respiratory distress: a randomized controlled trial. JAMA 2002;287:3238-3244.
Ferrer M, Esquinas A, Leon M, Gonzalez G, Alarcon A, Torres A. Noninvasive ventilation in severe hypoxemic respiratory failure: a randomized clinical trial. Am J Respir Crit Care Med 2003;168:1438-1444.(Jonathon Dean Truwit, M.D)
Figure 1. Suggested Application of Noninvasive Ventilation.
COPD denotes chronic obstructive pulmonary disease.
Noninvasive ventilation has been used in the care of other types of patients in the hope of avoiding intubation or reintubation. In this issue of the Journal, Esteban et al.2 report the results of their study of the use of noninvasive ventilation in patients with acute respiratory failure after extubation. Noninvasive ventilation did not result in reduced rates of reintubation, and delays in reintubation after the development of acute respiratory failure actually correlated with worsened survival rates. The latter finding is a matter of great concern as clinicians explore further applications of noninvasive ventilation.
When noninvasive ventilation is effective, clinical status generally improves within two hours after its application. Such changes can include reductions in the respiratory rate and the use of accessory muscles and improvements in pH, arterial carbon dioxide tension, and arterial oxygen tension. Given the data presented by Esteban et al.,2 a two-hour trial accompanied by quantitative assessment in patients in whom noninvasive ventilation is initiated is advisable. Furthermore, our interpretation of the data suggests that this approach is best limited to populations of patients in whom success has been demonstrated.
Randomized, controlled trials involving patients with COPD have demonstrated reductions in intubation rates as a result of the application of noninvasive ventilation during acute hypercapnic respiratory failure.1,3,4,5 Reductions in nosocomial complications and even in mortality have been recorded. Some studies have also found that patients with COPD who were randomly assigned to noninvasive ventilation had a shorter stay in the intensive care unit. Noninvasive ventilation has been applied to very ill, immunosuppressed patients with bilateral infiltrates, and reductions in intubation rates and mortality have been observed.6 Similarly, it has been observed that patients receiving noninvasive ventilation after thoracic surgery appear to benefit from this strategy, when outcomes are assessed in terms of intubation rates.1
Noninvasive ventilation has proved to be beneficial in patients with cardiogenic pulmonary edema in randomized, controlled trials.1,7,8 However, it is not clear whether continuous positive airway pressure alone results in maximal gain or whether bilevel positive airway pressure provides additional benefit. In one small study, the latter technique was associated with more myocardial infarctions than the former.8 Clearly, continuous positive airway pressure is of benefit, and in our opinion, clinicians should choose continuous positive airway pressure until further data indicate an advantage in association with the bilevel technique.
A recent study by Ferrer et al.9 suggests that extubation followed immediately by the application of noninvasive ventilation may confer significant benefit in patients who are initially intubated for acute respiratory failure and who meet established criteria for the discontinuation of mechanical ventilation but who have had unsuccessful trials of spontaneous breathing on three successive days. Reductions in ventilation time and in mortality were noted. In that study, two thirds of the patients had COPD or cardiogenic pulmonary edema. Nava et al. randomly assigned patients with COPD who were intubated for 48 hours to extubation and noninvasive ventilation or to continued invasive ventilation and conventional discontinuation after an unsuccessful initial spontaneous-breathing trial.10 The study demonstrated improved outcomes as measured by the percentage of patients in whom assisted ventilation could be discontinued, the duration of assisted ventilation, survival, the length of stay in the intensive care unit, and the incidence of ventilator-associated pneumonia. Currently, there are no data supporting the use of noninvasive ventilation to facilitate the discontinuation of assisted ventilation, other than in patients with COPD or cardiogenic pulmonary edema.
The use of noninvasive ventilation in patients in whom acute respiratory distress develops after extubation, and not as an immediately applied adjunct to extubation, has also been examined. A historical case–control study by Hilbert et al. showed a reduction in the rate of reintubation in patients with COPD.11 A recent randomized, controlled trial by Keenan et al. did not show a benefit in association with the application of noninvasive ventilation.12 However, less than 10 percent of the patients assigned to noninvasive ventilation had a diagnosis of COPD. Cardiac disease was the predominant diagnosis, but it is unclear whether cardiogenic pulmonary edema was present or not.
In the trial by Esteban et al.,2 the use of noninvasive ventilation failed to prove beneficial in patients in whom respiratory failure developed within 48 hours after extubation. These authors randomly assigned patients to medical treatment or noninvasive ventilation and compared outcomes. They found that reintubation rates were equal in the two groups but that mortality was higher in the noninvasive-ventilation group. The percentages of patients with COPD (12 percent) or cardiogenic pulmonary edema (7 percent) in the noninvasive-ventilation group were low but not statistically different from those in the control group. Mortality rates were higher in the noninvasive-ventilation group, predominantly because the mortality rate among the patients in that group who required reintubation was higher than that of the patients in the control group who required reintubation. The time to reintubation was considerably longer in the noninvasive-ventilation group than in the control group (median, 12 hours vs. 2 hours 30 minutes).
In our opinion, given the absence of supportive data, noninvasive ventilation when used to prevent reintubation should be limited to patients with COPD and perhaps those with cardiogenic pulmonary edema. Surveillance to determine which patients require early reintubation, if indicated, appears essential, given the results of the study by Esteban et al.
Successful noninvasive-ventilation strategies require a program that includes the availability of well-trained staff, careful selection of patients, and attention to patients' responses to noninvasive ventilation. Noninvasive ventilation appears best suited to patients with COPD, those with cardiogenic pulmonary edema, those who have just undergone lung surgery, and those who are immunosuppressed and have bilateral infiltrates. Some data do support the use of noninvasive ventilation in patients who have acute exacerbations of asthma, pneumonia, hypoxic respiratory failure, trauma, or the acute respiratory distress syndrome and patients who have restrictive lung disease and are acutely ill.1,13 However, because the evidence is insufficient at this time, the use of noninvasive ventilation in these populations cannot be uniformly recommended. Additional selection criteria include moderate-to-severe respiratory distress, tachypnea, accessory-muscle use, asynchronous chest–abdominal muscle use, hypercapnia, and moderate acidosis.
Factors favoring the successful application of noninvasive ventilation are a small volume of respiratory secretions; intact dentition; low scores on the Acute Physiology and Chronic Health Evaluation II; synchronous breathing; a good initial response in terms of pH, arterial carbon dioxide tension, and respiratory rate; and the ability to protect the airway.1 Many believe that with patients who have acute respiratory distress there is a fairly narrow window of opportunity for the use of noninvasive ventilation; they need to be sick enough for intervention but not sick enough to require immediate intubation. The initial six-to-eight-hour period of noninvasive ventilation is resource-intensive, and failure to intubate a patient who does not have a response is associated with increased mortality.
The article by Esteban et al.2 provides a valuable lesson for all practicing clinicians. The application of noninvasive ventilation is not without peril. Although the report addresses patients in whom respiratory failure develops after extubation, the lessons learned probably apply to all patients receiving noninvasive ventilation. A high level of vigilance is required to identify those who do not have a response, and adherence to defined selection and exclusion criteria should be maintained. Noninvasive ventilation is clearly developing its own place in the list of medical options for the treatment of acute respiratory failure; however, as with all treatments, there appear to be important risks that come with the benefits.
Source Information
From the Division of Pulmonary and Critical Care Medicine, University of Virginia, Charlottesville (J.D.T.); and the Division of Allergy, Pulmonary, and Critical Care Medicine, Vanderbilt University, Nashville (G.R.B.).
References
Liesching T, Kwok H, Hill NS. Acute applications of noninvasive positive pressure ventilation. Chest 2003;124:699-713.
Esteban A, Frutos-Vivar F, Niall D, et al. Noninvasive positive-pressure ventilation for respiratory failure after extubation. N Engl J Med 2004;350:2452-2460.
Brochard L, Mancebo J, Wysocki M, et al. Noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease. N Engl J Med 1995;333:817-822.
Plant PK, Owen JL, Elliott MW. Early use of non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease on general respiratory wards: a multicentre randomised controlled trial. Lancet 2000;355:1931-1935.
Keenan SP, Sinuff T, Cook DJ, Hill NS. Which patients with acute exacerbation of chronic obstructive pulmonary disease benefit from noninvasive positive-pressure ventilation? A systematic review of the literature. Ann Intern Med 2003;138:861-870.
Hilbert G, Gruson D, Vargas F, et al. Noninvasive ventilation in immunosuppressed patients with pulmonary infiltrates, fever, and acute respiratory failure. N Engl J Med 2001;344:481-487.
Masip J, Betbese AJ, Paez J, et al. Non-invasive pressure support ventilation versus conventional oxygen therapy in acute cardiogenic pulmonary oedema: a randomised trial. Lancet 2000;356:2126-2132.
Mehta S, Jay GD, Woodward RH, et al. Randomized prospective trial of bilevel versus continuous positive airway pressure in acute pulmonary edema. Crit Care Med 1997;25:620-628.
Ferrer M, Esquinas A, Arancibia F, et al. Noninvasive ventilation during persistent weaning failure: a randomized controlled trial. Am J Respir Crit Care Med 2003;168:70-76.
Nava S, Ambrosino N, Clini E, et al. Noninvasive mechanical ventilation in the weaning of patients with respiratory failure due to chronic obstructive pulmonary disease: a randomized, controlled trial. Ann Intern Med 1998;128:721-728.
Hilbert G, Gruson D, Portel L, Gbikpi-Benissan G, Cardinaud JP. Noninvasive pressure support ventilation in COPD patients with postextubation hypercapnic respiratory insufficiency. Eur Respir J 1998;11:1349-1353.
Keenan SP, Powers C, McCormack DG, Block G. Noninvasive positive-pressure ventilation for postextubation respiratory distress: a randomized controlled trial. JAMA 2002;287:3238-3244.
Ferrer M, Esquinas A, Leon M, Gonzalez G, Alarcon A, Torres A. Noninvasive ventilation in severe hypoxemic respiratory failure: a randomized clinical trial. Am J Respir Crit Care Med 2003;168:1438-1444.(Jonathon Dean Truwit, M.D)