Advantage of spontaneous breathing in patients with respiratory failure

Višnja Majerić Kogler

doi:10.22514/sv41.042009.2

Abstract

The fact that different modalities of mechanical ventilation are associated with a number of serious side effects and risks and can influence the clinical outcome of patients, the various modes of mechanical ventilation have, over the past ten years, been the subject of a wide variety of scientific studies. Many of these modalities are designed for partial ventilatory support, which might reflect the complexity of the issue of patient’s ventilator interactions when spontaneous breathing activity is present, compared to controlled mechanical ventilation. Spontaneous breathing modes during mechanical ventilation may integrate intrinsic feedback mechanisms that should help prevent ventilator- induced lung injury and improve synchrony between the ventilator and the patient’s demand. The improvements in pulmonary gas exchange, systemic blood flow, and oxygen supply to the tissue that have been observed when spontaneous breathing has been maintained during mechanical ventilation are reflected in the clinical improvement in the patient’ s condition. It is the aim of this article to review the effects of preserved spontaneous breathing activity during mechanical ventilation in patients with acute respiratory failure.

Highlights

Mechanical ventilation is one of the life support procedures closely associated with the development of modern intensive care medicine
The incidence of atelactasis and pulmonary dysfunction is lower during maintained spontaneous breathing with airway pressure release ventilation (APRV)/ BIPAP. These results clearly show that, even in patients requiring mechanical ventilation, maintained and unhindered spontaneous breathing can counteract the progressive deterioration in pulmonary gas exchange as a result of alveolar collapse. [15]
The improvements in pulmonary gas exchange, systemic blood flow, and oxygen supply to the tissue, which have been observed when spontaneous breathing has been maintained during mechanical ventilation, are reflected in the clinical improvement in the patient’s condition

Summary

Introduction

Mechanical ventilation is one of the life support procedures closely associated with the development of modern intensive care medicine. Continuous positive pressure ventilation and PEEP help to improve arterial oxygenation and affect the intrathoracic and extrathoracic vascular pressure gradients, such that return of the blood flow to the right ventricle is impaired and pulmonary vascular impedance is increased, resulting in enhanced right ventricular afterload Both these mechanisms represent the major determinants for the depression of cardiac output, reduction of kidney and splanchnic perfusion, glomerular filtration and sodium excretion during mechanical ventilation. Continuous positive pressure ventilation (CPPV) and PEEP help to improve arterial oxygenation and affect the intrathoracic to extrathoracic vascular pressure gradients, such that return of blood flow to the right ventricle is impaired and pulmonary vascular impedance is increased, resulting in enhanced right ventricular afterload The combination of both mechanisms is belived to represent the major determinants for the depression of cardiac output during mechanical ventilation. Both from a medical and from an economic point of view it would appear sensible to provide mechanical support with spontaneous breathing

Conclusion

Findings

The Acute Respiratory Distress Syndrom Network