CHRONIC VENTILATORY SUPPORT IN A CRITICALLY ILL PATIENT

Abstract

INTRODUCTION

Most patients admitted in the intensive care unit require some form of respiratory support. The support offered ranges from oxygen therapy by face mask through non-invasive techniques such as continuous positive airway pressure (CPAP) to full ventilatory support with endotracheal intubation. Mechanical ventilation replaces or supplements normal ventilation by the pulmonary system. In most instances the problem is primarily that of impaired CO2 elimination (ventilatory failure). In other cases, mechanical ventilation may be used as an adjunct in the treatment of hypoxemia (Hypoxic Respiratory Failure)[1]. Mechanical ventilation may be indicated in many disorders.   The main reason for instituting mechanical ventilation (MV) is the patient’s inability to oxygenate adequately. The loss of adequate alveolar ventilation, may be secondary to primary abnormalities of the pulmonary parenchyma, such as pneumonia, pulmonary oedema, or systemic disease that indirectly compromises pulmonary function, in all these conditions the basic etiopathogenic mechanism is severe injury of the capillary-alveolar membrane leading to hypoxic respiratory failure. CNS dysfunction and Neuromuscular impairment, leads to ventilatory failure [1,2]. Chronic Ventilator dependence means the use of mechanical ventilation for at least six hours daily for at least twenty-one days [3]. Tracheotomy is usually done electively when intubation is likely to be prolonged (over 14 days). This may also be done for the patient’s comfort and to facilitate weaning from the ventilator. Tracheotomy is often done as a percutaneous procedure in intensive care. Patients tolerate a tracheotomy much better than an orotracheal tube, sedation can usually be reduced, weaning is more rapid, and the stay in intensive care is reduced, it may help with tracheal toilet in patients with copious secretions and poor cough effort [1,2]. Many patients, who previously would have died from respiratory failure, now survive. Better ventilatory and monitoring equipment and improved understanding and management of lung and ventilation pathology have played an important role in improved prognosis