Non-invasive ventilation
Medical > Therapy > Special situations
Non-invasive ventilation (NIV) and Pulmonary Hypertension (PH)
With the new developments in the field of pulmonary arterial hypertension, there is growing interest from many physicians of different medical specialties about the care of such patients. With the prolonged survival of the patients, there are new issues in the care arising. One of them is the application of non-invasive ventilation (NIV).
The potential benefits over the classical endotracheal mechanical ventilation (ETMV) in PH patients are the avoidance of intubation, hence less infectious complications, a faster weaning from mechanical ventilation and, as a consequence, a shorter ICU stay and less costs. The mortality benefits of NIV in acute exacerbations of COPD and acute hydrostatic lung edema, are firmly established (2). In the tong-term NIV could be theoretically used as a bridge to lung transplantation. Unfortunately, currently there is very few evidence in this field.
The usual criteria for patient selection and contraindications should also apply to the group of patients with PH. Special caution must be raised about the criterium "hemodynamic unstability", especially in severe PH. Such patients should be considered "a priori" as candidates for ETMV only.
The concept of a "window of opportunity" should be applied. This means that a timely limited trial of 1-2 hours under NIV should be offered to deteriorating patients, still not meeting the criteria for intubation. This should be monitored in an ICU with a low threshold for switching to ETMV. From the large experience with ETMV and NIV, there are some well documented concerns about detrimental hemodynamic effects, caused by the rise in the intrathoracic and alveolar pressures. These include a decrease in venous return (and RAP) and following the increased RV-LV interdependence, a depression of the RV function and a rise in PVR. These can lead to critical low output heart failure (1,2). These effects are less pronounced during NIV compared to ETMV because of lower pressure levels generated. In coexisting LV dysfunction and raised PCWP, the effects on RV and PAP are unpredictable (1).
The potential NIV application can be discussed in the light of the Venice WHO classification of PH.
Patients with pulmonary hypertension associated to lung diseases and/or hypoxemia (WHO group III) may present with "classical" indications for NIV. These include obstructive sleep apnea syndrome, central sleep apnea syndrome, overlap syndrome, obesity-hypoventilation syndrome, COPD (esp. acute exacerbations) and restrictive lung diseases.
Generally, the PH in this group is very rarely severe (3,4). In this sense, the NIV represents a direct treatment of the underlying (and possibly acutely worsening) hypoxemia, hypercapnia and acidosis as well as apneas-hypopneas. As a consequence, NIV results in an indirect treatment of the worsening PH. Generally, it is believed that there should be a remarkable daytime hypoxemia as precondition for the establishment of daytime PH (5). Because of the less severe PH there are less concerns about triggering a low output heart failure as an side effect upon initiation of NIV. Actually the prevalence of this complication is reported to be about 1-2 % in these conditions (PH in WHO III group) with a proper selection for NIV (2) For a detailed discussion visit the official sleep medicine links listed below.
An overlap of OSAS in patients with severe PH may occur. However, the degree of PH does not well correlate with the severity of obstructive sleep apnea and both conditions are therefore seen as comorbidities. A CPAP trial is indicated. Given the generally good results (Apnea-Hypopnea Index normalization) in the presence of a good compliance with the therapy, there should be an echocardiographic PH reevaluation. The compliance is thought to be good with minimum of 4-5 hours per night on NIV or CPAP. The "hard" end points are the AHI reduction (ideally to AHI < 5/h) and improving day time blood gases. If additional O2 home therapy is indicated, it should be added to NIV or CPAP in order to correct the hypoxemia-triggered PH. Actually, the time point for reevaluation of the PH is set rather arbitrarily to 3-6 months (6). Then, it is justified to seek after other etiologies of a non-improving severe (out of proportion to the improving OSAS) PH, based on the proposed diagnostic algorhythm.
In Group II the pulmonary hypertension is secondary to the chronic left ventricular disease, so the primary goal is to treat the left heart failure. CPAP has been shown to be helpful in acute decompensations of left heart failure by reducing LV afterload and the alveolar edema. In Cheyne-Stoke's periodic breathing the servo-adapive bilevel NIV is a very promising therapeutic option.
In pulmonary arterial PAH and chronic thromboembolic pulmonary hypertension (CTEPH) (WHO-Groups I and IV), where severe PH may exists, there are no studies at all on NIV. For safety reasons it must be recommended that if a trial of NIV must be started for another respiratory comorbidity it must be done in a specialized center with experience in both, the treatment of PH and intensive care. One should distinguish two scenarios. In an acute situation (acutely worsening PH), even in the presence of an acute respiratory disease (i. e. pneumonia), the PAH or CTEPH patients may deteriorate rapidly with their pulmonary and systemic hemodynamics. Here, NIV should be generally avoided (contraindicated in hemodynamically unstable patients). The escalation of the specific vasodilative therapies and adrenergic substances in an ICU setting are much more important. A profound hypoxemia requires ETMV in this situation.
A chronically worsening PAH or CTEPH may theoretically be an indication for NIV. However, there are several issues to be commented: a respiratory failure is a rather pre-terminal event in these PH patients. The end-of-life issues should be ideally discussed earlier when the patient is in a more stable condition. If the patient is on a transplantation list, a particular effort should be guaranteed in spite of the dismal prognosis.
The role of CPAP or NIV (servo-adaptive BiPAP) therapies of Cheyne-Stoke's periodic breathing in IPAH patients (a common condition in appr. 30 % of the patients (7) has never been studied so far. Nocturnal oxygen therapy seems much more appropriate in this situation.
In conclusion, there is enough evidence of the beneficial effects and low risks of CPAP and NIV in WHO-Group III. In the therapy of acute or chronic respiratory failure in PH patients in WHO-Groups I and IV, however, NIV is contraindicated and patients should have access as soon as possible to a center of expertise in PH and intensive care.
References
1. Badouin S. Overview of the effects of mechanical ventilation on the pulmonary circulation. Chapter 35, Book "Pulmonary Circulation", edited by A. J. Peacock, 1996, Chapman & Hall, London
2. Metha S. and Hill N. Noninvasive Ventilation , pp. 540-577, AJRCCM, Vol. 163, 2001
3. Atwood Ch. et al. Pulmonary Arterial Hypertension and Sleep disordered Breathing, In "Diagnosis and Management of PAH: ACCP Evidence-Based Clinical Practice Guidelines", pp.72S-77S, Chest, Vol. 126, Nr. 1, July 2004
4. Schulz R. et al. Pulmonale Hypertonie und schlafbezogene Atmungsstörungen, pp. 270-274, Pneumologie Vol. 59, 2005
5. Stradling J. Pulmonary Circulation and Obstructive Sleep Apnea, Chapter 24, Book "Pulmonary Circulation", edited by A. J. Peacock, 1996, Chapman & Hall, London
6. Miguel A. et al. Pulmonary hypertension in obstructive sleep apnoea: effects of continuous positive airway pressure. A randomized, controlled cross-over study. European Heart Journal 2006, vol. 27, 1106-1113
7. R. Schulz et al. Nocturnal Periodic Breathing in Primary Pulmonary Hypertension. pp. 658-663, Eur Respir J, Vol. 19, 2002
Sleep Medicine links:
Swiss Society of Sleep Research, Sleep Medicine and Chronobiology
Deutsche Gesellschaft für Schlafforschung und Schlafmedizin
American Academy of Sleep Medicine
Australasian Sleep Association
Canadian Sleep Society
Back to > Medical > Therapy > Special situations
Non-invasive ventilation (NIV) and Pulmonary Hypertension (PH)
With the new developments in the field of pulmonary arterial hypertension, there is growing interest from many physicians of different medical specialties about the care of such patients. With the prolonged survival of the patients, there are new issues in the care arising. One of them is the application of non-invasive ventilation (NIV).
The potential benefits over the classical endotracheal mechanical ventilation (ETMV) in PH patients are the avoidance of intubation, hence less infectious complications, a faster weaning from mechanical ventilation and, as a consequence, a shorter ICU stay and less costs. The mortality benefits of NIV in acute exacerbations of COPD and acute hydrostatic lung edema, are firmly established (2). In the tong-term NIV could be theoretically used as a bridge to lung transplantation. Unfortunately, currently there is very few evidence in this field.
The usual criteria for patient selection and contraindications should also apply to the group of patients with PH. Special caution must be raised about the criterium "hemodynamic unstability", especially in severe PH. Such patients should be considered "a priori" as candidates for ETMV only.
The concept of a "window of opportunity" should be applied. This means that a timely limited trial of 1-2 hours under NIV should be offered to deteriorating patients, still not meeting the criteria for intubation. This should be monitored in an ICU with a low threshold for switching to ETMV. From the large experience with ETMV and NIV, there are some well documented concerns about detrimental hemodynamic effects, caused by the rise in the intrathoracic and alveolar pressures. These include a decrease in venous return (and RAP) and following the increased RV-LV interdependence, a depression of the RV function and a rise in PVR. These can lead to critical low output heart failure (1,2). These effects are less pronounced during NIV compared to ETMV because of lower pressure levels generated. In coexisting LV dysfunction and raised PCWP, the effects on RV and PAP are unpredictable (1).
The potential NIV application can be discussed in the light of the Venice WHO classification of PH.
Patients with pulmonary hypertension associated to lung diseases and/or hypoxemia (WHO group III) may present with "classical" indications for NIV. These include obstructive sleep apnea syndrome, central sleep apnea syndrome, overlap syndrome, obesity-hypoventilation syndrome, COPD (esp. acute exacerbations) and restrictive lung diseases.
Generally, the PH in this group is very rarely severe (3,4). In this sense, the NIV represents a direct treatment of the underlying (and possibly acutely worsening) hypoxemia, hypercapnia and acidosis as well as apneas-hypopneas. As a consequence, NIV results in an indirect treatment of the worsening PH. Generally, it is believed that there should be a remarkable daytime hypoxemia as precondition for the establishment of daytime PH (5). Because of the less severe PH there are less concerns about triggering a low output heart failure as an side effect upon initiation of NIV. Actually the prevalence of this complication is reported to be about 1-2 % in these conditions (PH in WHO III group) with a proper selection for NIV (2) For a detailed discussion visit the official sleep medicine links listed below.
An overlap of OSAS in patients with severe PH may occur. However, the degree of PH does not well correlate with the severity of obstructive sleep apnea and both conditions are therefore seen as comorbidities. A CPAP trial is indicated. Given the generally good results (Apnea-Hypopnea Index normalization) in the presence of a good compliance with the therapy, there should be an echocardiographic PH reevaluation. The compliance is thought to be good with minimum of 4-5 hours per night on NIV or CPAP. The "hard" end points are the AHI reduction (ideally to AHI < 5/h) and improving day time blood gases. If additional O2 home therapy is indicated, it should be added to NIV or CPAP in order to correct the hypoxemia-triggered PH. Actually, the time point for reevaluation of the PH is set rather arbitrarily to 3-6 months (6). Then, it is justified to seek after other etiologies of a non-improving severe (out of proportion to the improving OSAS) PH, based on the proposed diagnostic algorhythm.
In Group II the pulmonary hypertension is secondary to the chronic left ventricular disease, so the primary goal is to treat the left heart failure. CPAP has been shown to be helpful in acute decompensations of left heart failure by reducing LV afterload and the alveolar edema. In Cheyne-Stoke's periodic breathing the servo-adapive bilevel NIV is a very promising therapeutic option.
In pulmonary arterial PAH and chronic thromboembolic pulmonary hypertension (CTEPH) (WHO-Groups I and IV), where severe PH may exists, there are no studies at all on NIV. For safety reasons it must be recommended that if a trial of NIV must be started for another respiratory comorbidity it must be done in a specialized center with experience in both, the treatment of PH and intensive care. One should distinguish two scenarios. In an acute situation (acutely worsening PH), even in the presence of an acute respiratory disease (i. e. pneumonia), the PAH or CTEPH patients may deteriorate rapidly with their pulmonary and systemic hemodynamics. Here, NIV should be generally avoided (contraindicated in hemodynamically unstable patients). The escalation of the specific vasodilative therapies and adrenergic substances in an ICU setting are much more important. A profound hypoxemia requires ETMV in this situation.
A chronically worsening PAH or CTEPH may theoretically be an indication for NIV. However, there are several issues to be commented: a respiratory failure is a rather pre-terminal event in these PH patients. The end-of-life issues should be ideally discussed earlier when the patient is in a more stable condition. If the patient is on a transplantation list, a particular effort should be guaranteed in spite of the dismal prognosis.
The role of CPAP or NIV (servo-adaptive BiPAP) therapies of Cheyne-Stoke's periodic breathing in IPAH patients (a common condition in appr. 30 % of the patients (7) has never been studied so far. Nocturnal oxygen therapy seems much more appropriate in this situation.
In conclusion, there is enough evidence of the beneficial effects and low risks of CPAP and NIV in WHO-Group III. In the therapy of acute or chronic respiratory failure in PH patients in WHO-Groups I and IV, however, NIV is contraindicated and patients should have access as soon as possible to a center of expertise in PH and intensive care.
References
1. Badouin S. Overview of the effects of mechanical ventilation on the pulmonary circulation. Chapter 35, Book "Pulmonary Circulation", edited by A. J. Peacock, 1996, Chapman & Hall, London
2. Metha S. and Hill N. Noninvasive Ventilation , pp. 540-577, AJRCCM, Vol. 163, 2001
3. Atwood Ch. et al. Pulmonary Arterial Hypertension and Sleep disordered Breathing, In "Diagnosis and Management of PAH: ACCP Evidence-Based Clinical Practice Guidelines", pp.72S-77S, Chest, Vol. 126, Nr. 1, July 2004
4. Schulz R. et al. Pulmonale Hypertonie und schlafbezogene Atmungsstörungen, pp. 270-274, Pneumologie Vol. 59, 2005
5. Stradling J. Pulmonary Circulation and Obstructive Sleep Apnea, Chapter 24, Book "Pulmonary Circulation", edited by A. J. Peacock, 1996, Chapman & Hall, London
6. Miguel A. et al. Pulmonary hypertension in obstructive sleep apnoea: effects of continuous positive airway pressure. A randomized, controlled cross-over study. European Heart Journal 2006, vol. 27, 1106-1113
7. R. Schulz et al. Nocturnal Periodic Breathing in Primary Pulmonary Hypertension. pp. 658-663, Eur Respir J, Vol. 19, 2002
Sleep Medicine links:
Swiss Society of Sleep Research, Sleep Medicine and Chronobiology
Deutsche Gesellschaft für Schlafforschung und Schlafmedizin
American Academy of Sleep Medicine
Australasian Sleep Association
Canadian Sleep Society
Back to > Medical > Therapy > Special situations
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SSPH Research Prize 2012
Deadline for submission: April 30, 2012
Further information
Symposium "pulmonal-arterielle Hypertension im Kindesalter"
Donnerstag, 10. Mai 2012, 16.00-18.00, Bern
Further information:
5th International Congress of the Swiss Society of Pulmonary Hypertension (SSPH)
28.-29. September 2012, Thun, Congress Hotel Seepark Thun
Informationen: www.imk.ch/sgph2012
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