© Springer International Publishing Switzerland 2016
Antonio M. Esquinas (ed.)Noninvasive Mechanical Ventilation and Difficult Weaning in Critical Care10.1007/978-3-319-04259-6_2121. Noninvasive Positive-Pressure Ventilation in the Management of Respiratory Distress in Cardiac Diseases
(1)
Department of Internal Medicine Lenox Hill Hospital, NSLIJ/Lenox Hill Hospital, New York, NY, USA
Keywords
Bi-level positive airway pressureCoronary artery bypass graftCardiac surgeryCardiogenic pulmonary edemaCongestive heart failureContinuous positive airway pressureNoninvasive ventilation21.1 Introduction
Noninvasive positive-pressure ventilation (NIPPV) is the application of respiratory support (pressurized air and oxygen) without the use of an artificial airway such as endotracheal intubation (ETI) or a tracheostomy tube. NIPPV exists as two main types, NIPPV with bi-level positive airway pressure (BPAP) and NIPPV with continuous positive airway pressure (CPAP). Over the past 30 years, NIPPV has shown well-studied efficacy for the treatment of respiratory distress caused by multiple etiologies.
The beneficial treatment effects of NIPPV occur in multiple pathophysiologic states. Acidosis and hypercapnia are treated by improved alveolar ventilation, hypoxia is reversed through improved alveolar recruitment and therapeutic concentrations of fraction of inspired oxygen (FiO2), work of breathing is improved with unloading of the diaphragm and accessory muscles as well as by reducing inspiratory energy expenditure, and cardiac function is modulated secondary to a reduction in afterload.
Through the above actions, and with proper patient selection, ventilator type, settings, and with close monitoring, NIPPV can often avoid a patient progressing from respiratory distress to respiratory arrest and the need for invasive methods of ventilation such as ETI and all of its noted sequelae. Indeed, NIPPV may be the preferred method of ventilatory support in many cases [1].
The general contraindications to NIPPV are well described, although what precisely constitutes a relative versus an absolute contraindication is a topic of some debate. Relative contraindications may include a need for full-time ventilatory support, insufficient caregiver support, and severe dysphagia. Absolute contraindications require clinical judgment, but may include upper airway obstruction, lack of adequate cough, poor ability of the patient to handle secretions, inability of the patient to sync with the selected settings, and significant air leakage caused by poor mask fit.
NIPPV has been best studied in the setting of acute respiratory distress secondary to pulmonary diseases such as asthma, chronic obstructive pulmonary disease, and pneumonia. The evidence for its efficacy in respiratory distress resulting from cardiac causes, however, is somewhat less well defined. As will be discussed, its utility has been best shown in the setting of acute cardiogenic pulmonary edema (ACPE) and congestive heart failure (CHF).
While the role of NIPPV in respiratory failure after general surgical procedures has been examined, the evidence for its efficacy after surgical and percutaneous procedures such as coronary artery bypass graft (CABG), valvular procedures, and percutaneous coronary intervention (PCI) is far more limited.
21.2 Discussion
21.2.1 ACPE and CHF
Acute heart failure exacerbation is one of the main causes of hospitalization in the United States, responsible for more than one million hospital admissions per year. At least 25 % of these patients present with ACPE and a significant portion of those require some form of ventilatory support [2].
There is strong evidence to support the use of both CPAP and BPAP in the setting of respiratory distress secondary to ACPE [3, 4]. Various guidelines recommend a trial of NIPPV in these patients [2]. Gray et al. [5] stated, “CPAP and BPAP safely provide earlier improvement and resolution of breathlessness, respiratory distress, and metabolic abnormalities in severe ACPE. We recommend that noninvasive ventilation (CPAP or NIPPV) should be considered as adjunctive therapy in patients with severe ACPE in the presence of severe respiratory distress or when there is a failure to improve with pharmacological therapy.” Other meta-analyses have found that, although neither method is superior in terms of mortality when compared against each other, BPAP is associated with more rapid resolution of dyspnea and better oxygenation than CPAP or standard oxygen therapy with nasal cannula [2].
The safety and efficacy of NIPPV to limit the need for ETI is well documented. However, many, though not all, studies fail to show a decrease in 30-day mortality among all manner of NIV compared with ETI. However, a recent meta-analysis suggests that the failure of more studies to show improved 30-day mortality is a consequence of their low power to detect this outcome [3]. Of note, NIV has been shown to significantly decrease the risk of mortality when compared with medical management alone in the form of standard oxygen therapy [3]. Importantly, historical reports of an increased risk of acute myocardial infarction with NIPPV use in the CHF and ACPE populations has not been shown in multiple study populations [2, 3, 6].
CPAP should be started at 10–15 cmH2O and titrated by 5 cmH2O every 5 min based on the patient’s clinical status. If BPAP is selected, inspiratory positive airway pressure (IPAP)/expiratory positive airway pressure (EPAP) should be started at 10/5 and titrated as for CPAP. Arterial blood gas monitoring, although not absolutely required in all cases, should be performed for any patient who does not show appropriate clinical improvement after ~10 min of therapy. A rising PaCO2 after treatment has begun should alert the physician that the patient may be failing NIPPV and is in danger of imminent respiratory arrest. More aggressive treatment with ventilatory support in the form of BPAP (if CPAP had been used) or ETI (if BPAP had been attempted) must be urgently considered in these cases. Continuous end-tidal CO2 monitoring may also be used where available. In all cases, close monitoring of patients is a necessity and transfer of these patients to a monitored unit is the norm [5].
Related posts:
Predictive Models of Prolonged Mechanical Ventilation and Difficult Weaning
Postoperative Continuous Positive Airway Pressure (CPAP)
Noninvasive Mechanical Ventilation in Postoperative Bariatric Surgery
Noninvasive Mechanical Ventilation in Tetraplegia
Criteria for Discharging Patients with Prolonged and Difficult Weaning from Intensive Care Unit to Weaning Center
Organization of a Weaning Unit
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
