The Difficult-to-Wean Patient

Abstract and Introduction

Abstract

Up to 20% of patients requiring mechanical ventilation will suffer from difficult weaning (the need of more than 7 days of weaning after the first spontaneous breathing trial), which may depend on several reversible causes: respiratory and/or cardiac load, neuromuscular and neuropsychological factors, and metabolic and endocrine disorders. Clinical consequences (and/or often causes) of prolonged mechanical ventilation comprise features such as myopathy, neuropathy, and body composition alterations and depression, which increase the costs, morbidity and mortality of this. These difficult-to-wean patients may be managed in two type of units: respiratory intermediate-care units and specialized regional weaning centers. Two weaning protocols are normally used: progressive reduction of ventilator support (which we usually use), or progressively longer periods of spontaneous breathing trials. Physiotherapy is an important component of weaning protocols. Weaning success depends strongly on patients' complexity and comorbidities, hospital organization and personnel expertise, availability of early physiotherapy, use of weaning protocols, patients' autonomy and families' preparation for home discharge with mechanical ventilation.

Introduction

Up to 40% of patients admitted to intensive care units (ICUs) may require mechanical ventilation (MV) due to acute respiratory failure (ARF) or acute on chronic respiratory failure (ACRF),^[1] and this need is increasing.^[2] Most ACRF patients and, to a lesser extent, some patients with de novo ARF, may be treated with noninvasive MV,^[3,4] whereas a minority of these patients in the ICU need invasive MV. There is evidence that 65–85% of these patients undergoing invasive MV, under appropriate clinical conditions, can be successfully extubated, whereas up to 20% of patients will need a prolonged ICU length of stay (LOS) due to difficult weaning.^[2] As a consequence of advances in intensive care that have allowed increasing numbers of patients to survive, there is a large and growing population of patients with partial or complete dependence on MV and other intensive care therapies. Recent estimates indicate that there are more than 100,000 such patients in the USA, a number that is also increasing in many other developed countries. This condition is devastating for patients and imposes heavy burdens on healthcare systems (exceeding US$20 billion each year for the US healthcare system as a whole) and family members, who may suffer from depression and practical and financial hardships, with patients' nonprofessional caregivers having to face tasks that require high skills.^[5]

Cite this: The Difficult-to-wean Patient - Medscape - Oct 01, 2010.

Box 1. Factors associated with prolonged weaning.
Systemic Chronic diseases, comorbidities, nutrition and metabolic disturbances Severity of illness Impaired cardiovascular performance Left ventricular dysfunction, myocardial ischemia and cardiomyopathy Neurologic Critical illness neuromuscular abnormalities Respiratory Unresolved causes of respiratory failure Imbalance between work of breathing and respiratory muscle capacity Upper airway obstruction Treatment complications Ventilator-associated pneumonitis and infections Barotrauma Tracheostomy Sedation Cognitive Delirium, depression and anxiety Sleep deprivation Treatment setting Weaning protocols Staffing Staff training

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