Role of Mechanical Ventilation in Management of Heart Failure

Abstract

Heart failure results in high hospitalization rates and mortality; up to 40% of patients die within 1 year of first hospitalization, making the survival rate bleaker than that for nearly all cancers. It is estimated that by 2030, an additional 3 million people will have HF, a 25.0% increase in prevalence from 2010 in the United States.Heart failure is a common comorbidity in critical ill patients admitted to ICU and in many times it (with its complications) may be the cause of admission to ICU. The pulmonary manifestations of heart disease are diverse. Patients with CHF are prone to pulmonary complications, sleep disordered breathing, pulmonary edema, and pleural effusions. Pulmonary function is frequently abnormal, with a fall in vital capacity shown to precede the clinical recognition of CHF. While a restrictive defect may be seen in patients with both chronic CHF and acute pulmonary edema, significant airflow obstruction is more likely to occur in the latter. Because of its valuable cardiopulmonary effects, mechanical ventilation has a great role in management of cases of acute and chronic heart failure. It improves oxygen delivery to the remainder of the body by decreasing oxygen consumption so it reverses hypoxic pulmonary vasoconstriction and reduce pulmonary artery pressure. It also prevents the negative swings in intrathoracic pressure so selectively decreases LV afterload, as long as the increases in lung volume and intrathoracic pressure are small.In patients with hypervolemic heart failure, this afterload reducing effect can result in improved LV ejection, increased cardiac output and reduced myocardial oxygen demand. Mechanical ventilation can be applied to patients through invasive and noninvasive methods. Invasive ventilation is the traditional method of mechanical ventilation. Nowadays, it is used usually after failure of noninvasive methods. However, intubation and invasive mechanical ventilation should be performed without delay inserious situations as in acute respiratory failure with respiratory exhaustion, hemodynamic instability, cardiogenic shock, impaired consciousness, severe cardiac arrhythmias. Noninvasive ventilation is used to prevent the complications of noninvasive ventilation. It can be used in acute heart failure with cardiogenic pulmonary edema and in chronic heart failure with sleep disordered breathing. Noninvasive ventilation can be used outside ICU and even at home usually by using BIPAP, adaptive servo ventilation and CPAP modes. It was reported that chronic adaptive servo ventilation therapy not only eliminates sleep disordered breathing but also increases left ventricular ejection fraction. So, mechanical ventilation is a well established useful non-pharmacologic therapeutic tool in management of heart failure; not only in late stages but also in earlier stages where quality of patient’s life can be successfully improved