Prolonged mechanical ventilation requiring

Table 5 Outcomes for Patients Requiring Prolonged Mechanical Ventilation... 

MacIntyre NR, Epstein SK, Carson S, et al. Management of patients requiring prolonged mechanical ventilation reptat of a NAMDRC consensus conference. Chest 2005 128(6) 3937-3954. 

Thompson MJ, Elton RA, Mankad PA, et al. Prediction of requirement for, and outcome of, prolonged mechanical ventilation following cardiac surgery. Cardiovasc Surg 1997 5(4) 376-381. 

Each year, over 400,000 patients in the United States receive mechanical ventilation as a result of acute or acute-on-chronic respiratory failure (1,2). About a quarter of acutely ventilated patients repeatedly fail attempts at weaning and may require prolonged mechanical ventilation (PMV) (Fig. 1) (3,4). The proportion of patients experiencing PMV ranges between 0% and 20% (5-13). Out of patients who survive PMV, 9-66% become dependent on long-term mechanical ventilation (LTMV) (4,9,14-21). Two factors account for these wide variations in the outcome. The first factor is differences in patient population. The second one is the nosology of what constitutes PMV and what constitutes LTMV is unsatisfactory. 

Rumbak MJ, Graves AE, Scott MP, et al. Tracheostomy tube occlusion protocol predicts significant tracheal obstruction to air flow in patients requiring prolonged mechanical ventilation. Crit Care Med 1997 25(3) 413 17. 

Richard C, Kyle U, Chevrolet JC, et al. Lack of effects of recombinant growth hormone on muscle function in patients requiring prolonged mechanical ventilation a prospective, randomized, controlled study. Crit Care Med 1996 24(3) 403M 13. 

This chapter addresses the importance of integrating the process of rehabilitation within the milieu of critical care. A conceptual model will be presented to show how rehabilitation can be organized within the ICU, incorporating the whole of the patient s journey irrespective of their length of stay (LOS) within the ICU. The chapter will focus on those patients who require prolonged mechanical ventilation (PMV), i.e., >21 days and will be presented from a U.K. perspective. Case examples from my own critical care practice will be used to demonstrate how a rehabilitation framework of care impacts upon patient mortality, quahty of care, and ICU costs. Finally, recommendations will be made for future practice. 

Recent advances in intensive care have resulted in an increased salvage of critically ill patients a number of patients have become dependent upon mechanical ventilation as a chronic form of life support (1). The increased use of prolonged mechanical ventilation (PMV) has led to greater intensive care unit (ICU) bed use, resource consumption, and costs (2,3). It is important to characterize such patients to define treatment goals and expectations, to establish ventilatory care units for their specialized care, and to provide prognostic information for overall survival, morbidities, and health-related quality of life. The goals of this chapter are to provide definitions of PMV, to characterize the patient population requiring this modality of treatment, and to briefly describe a multidiscipUnaiy approach to treatment. 

Figure 1 Potential sites of care for patients requiring PMV. Sites toward the bottom of the figure have fewer medical resources and lower costs but allow greater patient independence and a higher quality of life. Abbreviation PMV, prolonged mechanical ventilation. Source From Make BJ, Hill NS, Goldberg AI, et al. Mechanical ventilation beyond the intensive care unit report of a consensus conference of the American college of chest physicians. Chest 1998 113 295S.

As a consequence of their growing numbers, prolonged care of a VAI (>30 days) in the ICU has rapidly increased the costs to the health care system in the United States, it has been estimated that patients requiring prolonged mechanical ventilation (PMV) account for as much as 40% of the ICU budget (5). Nevertheless, in 1995, a U.S. survey of 300 randomly selected acute care units reported that over 11,000 patients had received PMV at a cost of 9 million per day. Of these patients, 17% were awaiting placement outside the ICU, and 12% remained in ICU as they could not be reimbursed for care elsewhere (6). Although... 

Burns SM, Marshall M, Burns JE, et al. Design, testing, and results of an outcomes-managed approach to patients requiring prolonged mechanical ventilation. Am J Crit Care 1998 7(1) 45-57. 

Prolonged mechanical ventilation (PMV) has been defined as the need for ventilatory support for >21 consecutive days for >6 hr/day (1). Patients who require PMV could be classified as chronically critically ill, as they depend on life support for survival. PMV is part of the continuum of critical care medicine. 

In this chapter, we have highlighted the basic principles of managing the discharge home of the patient who requires prolonged mechanical ventilation. Although this may present major challenges to all concerned, the benefits in health-related quality of life and life expectancy may be substantial. Although some patients do find that the burden of HMV to be very difficult, most adjust with the help of home supports and many go on to achieve the unexpected (16). 

Therefore, nutritional assessment and management is an important therapeutic option among patients with chronic respiratory diseases (10), especially those requiring prolonged mechanical ventilation (PMV) in ICU (11). Table 1 emphasizes the effects of malnutrition on the respiratory function in patients in ICU. However, specific nutritional deficiencies such as hypophosphatemia (12) have been associated with respiratory failure and impaired lipid synthesis (13) and may cause an abnormal increase in the fat mass. 

Paralysis usually is reserved for cases in whom sedation alone does not improve the effectiveness of mechanical ventilation. Neuromuscular blockers may lead to prolonged skeletal muscle weakness and should be avoided if possible. Patients requiring neuromuscular blockade are to be monitored and intermittent boluses should be utilized. 

A specialized form of conscious sedation is occasionally required in the ICU, when patients are under severe stress and require mechanical ventilation for prolonged periods. In this situation, sedative-hypnotic drugs or low doses of intravenous anesthetics, neuromuscular blocking drugs, and dexmedetomidine may be combined. 

Avoid imnecessary stimulation, which may induce rigidity and spasms. The primary treatment for spasms and rigidity is sedation with a benzodiazepine, such as midazolam or diazepam. Additional sedation may be provided with propofol or a phenothiazine, usually chlorpromazine. In severe disease prolonged spasms and respiratory dys-fimction will necessitate tracheal intubation and mechanical ventilation will be required. If the patient has been intubated and sedation alone is inadequate to control spasms, a neuromuscular blocking drug, e.g., intermittent doses of pancuronium or a continuous infusion of atracurium, will be required. 

Donepezil acts primarily as a reversible inhibitor of acetylcholinesterase with a half-life of over 70 hours. Prolonged paralysis lasting several hours and requiring postoperative mechanical ventilation in the intensive care unit has been reported after the use of suxamethonium in a patient taking long-term donepezil (285). 

An extreme example reported in 1993 involved a 55-year-old obese man with no history of allergy to penicillin, who had on earlier occasions received sodium thiopental without reaction on this occasion he stopped breathing and had severe bronchial constriction and vascular collapse requiring prolonged resuscitation and mechanical ventilation (11). 

Concurrent with initiation of anticonvulsants, vital signs should be assessed, an adequate and protected airway should be established, ventilation should be maintained, and oxygen should be administered. Patients who seize for prolonged periods will require intubation and mechanical ventilation. Arterial blood gas determinations should be done frequently to assess for metabolic and/or respiratory acidosis. Metabolic acidosis resolves quickly following termination of GCSE however, sodium bicarbonate should be given if the pH is less than 7.2. If the patient has respiratory acidosis, assisted ventilation should correct the imbalance. 

It has been estimated that every year between 5 and 10% of patients admitted to hospitals in the United States and Europe will acquire an infection that was not present before they were admitted to the hospital [1]. A number of these nosocomial (hospital-acquired) infections lead to the patient s death at one extreme or, at the least, require additional antimicrobial chemotherapy. Among critically ill patients, the prevalence of hospital-acquired infection can reach 50% in intensive care units, where patients remain for prolonged periods, often undergoing invasive therapeutic support, such as mechanical ventilation. Within hospitals, the surgical and medical wards usually have the highest infection rates, while pediatric and neonatal services have the lowest. 

Gillespie DJ, Marsh HM, Divertie MB, et al. Clinical outcome of respiratory failure in patients requiring prolonged (greater than 24 hours) mechanical ventilation. Chest 1986 90(3) 364-369. 

Many lives are saved in critically ill patients by the introduction of an endotracheal tube (ETT) and mechanical ventilation. Most patients are capable of weaning from such invasive support once the acute process has resolved. Approximately 10% to 24% (1,2) are unable to wean from endotracheal intubation and require the surgical placement of a tracheostomy. Although timing of tracheostomy placement is controversial, a tracheostomy may offer advantages over more prolonged intubation (3). 

In a study of 91 ventilator users with DMD, 51 went on to require continuous NIPPV for 6.3 4.6 (range to 25) years. None of the 34 full-time NIPPV users who had access to MAC died from respiratory complications, whereas three died from severe cardiomyopathy. Five patients with no breathing capacity were extubated or decannulated to continuous NIPPV and five became continuously dependent on NIPPV for one year or more without ever being hospitalized (15). It has previously been reported that DMD patients undergoing tracheostomy tend to have a prolongation of survival of about seven years but also have a tendency to die from complications related to invasive mechanical ventilation (IMV) (24). 

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