© Springer International Publishing Switzerland 2016
Antonio M. Esquinas (ed.)Noninvasive Mechanical Ventilation10.1007/978-3-319-21653-9_5555. Noninvasive Mechanical Ventilation in Older Patients
(1)
Respiratory Intensive Care Unit Clinic, Sureyyapasa Chest Diseases and Thoracic Surgery Teaching and Research Hospital, Istanbul, 34732, Turkey
Keywords
Acute respiratory failureChronic respiratory failureOlder patientsNoninvasive ventilationAbbreviations
ARF
Acute respiratory failure
COPD
Chronic obstructive pulmonary disease
CPAP
Continuous positive airway pressure
CRF
Chronic respiratory failure
DNI
Do-not-intubate order
ICU
Intensive care unit
NIMV
Noninvasive mechanical ventilation
55.1 Introduction
Prolonged human life has led to an increase in intensive care unit (ICU) admissions of older patients (>65 years). Older patients constitute 42–52 % of ICU admissions and 60 % of ICU days [1]. With limited ICU beds and an ever-increasing elderly population, physicians need to be aware of the differences in treatment and diagnoses of these patients, to provide the best care.
The incidence of acute respiratory failure (ARF) increases significantly with age [2]. Aggressive treatment of ARF, such as invasive mechanical ventilation, should be limited in these patients, especially those over 80, due to their low survival rate. Thus, noninvasive mechanical ventilation (NIMV) plays a crucial role in the treatment of ARF in these patients. As with the younger population, NIMV also decreases intubation and mortality rates in these patients with exacerbations of chronic obstructive pulmonary disease (COPD) and acute pulmonary edema. It also prevents post-extubation ARF [3]. In addition, NIMV is frequently recommended for the respiratory support of patients with a do-not-intubate (DNI) order as comfort palliative treatment [4].
The aim of this chapter is to define and elaborate the particular circumstances related to NIMV treatment indications, methods, recommendations, and outcomes in older patients.
55.2 Pathophysiology
Aging is a process that leads to a decrease in physiological reserves in the respiratory system, as well as in other organ systems. Loss of function in the respiratory system is due to changes, both in the chest wall and the lung [5]. Increased stiffness and consequent decreased compliance of the thoracic cage is caused by cartilage calcification, kyphosis, and vertebral collapse [5]. Reduction in respiratory muscle strength may cause a reduction in the strength of the diaphragm and accessory respiratory muscles, resulting in decreased maximal inspiratory and expiratory pressures [5]. Decreased elasticity with age causes the loss of supporting tissues around the small airways with a resulting increased tendency for airway closure at small volumes [5]. Thus, the smaller airways lead to less ventilation and ultimately a ventilation-perfusion mismatch. The ventilatory response to hypoxia and hypercapnia also decreases in the older population [5]. Decreased mucociliary clearance in older patients can also be a handicap for NIMV treatment [5].
NIMV improves many of the above-mentioned adverse changes. For instance, it corrects collapsed alveoli and ventilation-perfusion mismatch, and it facilitates reduction in work of breathing by applying positive end-expiratory pressure [6]. It also reduces the afterload in patients with acute cardiogenic pulmonary edema by increasing intrathoracic pressure. NIMV resets decreased carbon dioxide sensitivity of the ventilatory center [6]. It raises lung volume, improves lung compliance, and reduces dead space [6].
55.3 NIMV and Acute Respiratory Failure
The incidence of ARF increases with each decade until the age of 85 years [7]. In addition to physiological changes in the respiratory system with aging, comorbidities (cardiac, neurological, and infectious), the presence of acute illness (malnutrition, delirium), and prior respiratory disease may all predispose older patients to ARF [7]. Non-pulmonary causes of ARF are more common in older patients and these added complexities in the etiology lead to diagnostic difficulties. Nonspecific presentations and atypical manifestations also contribute to difficulties in diagnosis.
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