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CHAPTER 60: Liberation From Mechanical Ventilation 541

reintubation must be weighed against those of continued mechanical
TABLE 60-3 Reversible Factors Contributing to Ventilatory Failure—Daily
Correction of Reversible Contributors to Ventilatory Failure ventilation. We extubate these unusual patients with personnel who
are skilled at endotracheal intubation nearby, should reintubation be
Expedites Patient Recovery
required. In addition, we ensure ready access to NIPPV, which may avert
Reduce Respiratory Load Improve Respiratory Strength the need for reintubation in carefully selected patients.
Resistance Replace K , Mg , PO to normal Finally, the role of tracheostomy to expedite liberation is controversial
+
2+
2−
4 (see Chap. 46). To date, no study has convincingly demonstrated benefit to
Inhaled bronchodilators Treat sepsis
early elective tracheostomy to expedite liberation, ICU or hospital stay. 74-76
Corticosteroids Nutritional support without overfeeding (aim While there are insufficient data in the era of low-pressure endotracheal
Removal of excess airway secretions to achieve a secretion normal prealbumin) tube cuffs to offer evidence-based recommendations, we employ early
Treatment of upper airway obstructions Consider stopping aminoglycosides rule out: tracheostomy if a patient is very unlikely to regain airway competence
Neurologic disease/occult seizures in the near future (eg, catastrophic stroke where a trial of therapies is
requested). If 14 days have elapsed and a patient is making no progress
Elastance Hypothyroidism in weaning or if a patient is approaching 21 days with poor progress we
Treat pneumonia Oversedation also offer tracheostomy as a route for prolonged mechanical ventilation
or to expedite further weaning efforts.
Treat pulmonary edema Critical illness myopathy/polyneuropathy
Reduce dynamic hyperinflation
Drain large pleural effusions KEY REFERENCES
Evacuate pneumothoraces
• Barr J, Fraser GL, Puntillo K, et al. Clinical practice guidelines for
Treat ileus the management of pain, agitation, and delirium in adult patients
in the intensive care unit. Crit Care Med. 2013;41:263-306.
Minute Volume
• Brochard L, Rauss A, Benito S, et al. Comparison of three methods
Detect intrinsic PEEP of gradual withdrawal from ventilatory support during weaning from
Bronchodilators mechanical ventilation. Am J Respir Crit Care Med. 1994;150:896-903.
Antipyretics • Determann RM, Royakkers A, Wolthuis EK, et al. Ventilation with
lower tidal volumes as compared with conventional tidal volumes
Treat sepsis
for patients without acute lung injury: a preventive randomized
Therapy for pulmonary embolism controlled trial. Crit Care. 2010;14:R1.
Maintain least PEEP possible • Ely EW, Bennett PA, Bowton DL, et al. Large-scale implementation
Correct metabolic acidoses of a respiratory therapist-driven protocol for ventilator weaning.
Am J Respir Crit Care Med. 1999;159:439-446.
Resuscitate shock
• Esteban A, Frutos F, Tobin MJ, et al. A comparison of four meth-
Prevent hypovolemia
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Avoid overfeeding Med. 1995;332:345-350.
• Esteban A, Frutos-Vivar F, Ferguson ND, et al. Noninvasive posi-
for weaning failure, it is reasonable to perform a careful trial of extu- tive-pressure ventilation for respiratory failure after extubation. N
bation. The following are among the clinical situations which could Engl J Med. 2004;350:2452-2460.
prompt consideration for a trial of extubation in such patients: • Kress JP, Pohlman AS, O’Connor MF, Hall JB. Daily interruption
of sedative infusions in critically ill patients undergoing mechani-
1. When an endotracheal tube has been in place for more than 7 days; cal ventilation. N Engl J Med. 2000;18;342(20):1471-1477.
endotracheal tube resistance increases with time and could contrib-
ute to failed breathing trials. • Levine S, Nguyen T, Taylor N, et al. Rapid disuse atrophy of dia-
2. When the patient experiences repeated episodes of bronchospasm phragm fibers in mechanically ventilated humans. N Engl J Med.
2008;358:1327-1335.
upon awakening from sedation; the endotracheal tube can cause
reflex bronchospasm in some individuals. • Schweickert WD, Pohlman MC, Pohlman AS, et al. Early physical
therapy in mechanically ventilated, critically ill patients: a ran-
3. When patients become overwhelmingly anxious when awakened to domised controlled trial. Lancet. 2009;373:1874-1882.
breathe through the endotracheal tube and the amount of sedative • Terragni PP, Antonelli M, Fumagalli R, et al. Early vs late tra-
required for comfort causes hypoventilation. We are particularly cheotomy for prevention of pneumonia in mechanically venti-
careful to ensure that cardiopulmonary reasons for failure have been lated adult ICU patients: a randomized controlled trial. JAMA.
reversed in these patients. 2010;303:1483-1489.
4. When patients with restrictive chest wall disease (eg, obesity) repeat- • Trouillet JL, Luyt CE, Guiguet M, et al. Early percutaneous tra-
edly desaturate every time PEEP is decreased to less than 10 cm H O; cheotomy versus prolonged intubation of mechanically ventilated
2
some obese patients require more than 5 cm H O to prevent atelectasis patients after cardiac surgery: a randomized trial. Ann Intern Med.
2
while intubated yet maintain adequate oxygenation when extubated. 2011;154:373-383.
5. When patients with severe restrictive or obstructive lung disease breathe • Tuxen DV, Lane S. The effects of ventilatory pattern on hyperinfla-
rapidly and shallowly (a rapid shallow breathing index or ƒ/V>125 tion, airway pressures, and circulation in mechanical ventilation
t
breaths/min per liter); for some end-stage patients rapid shallow of patients with severe air-flow obstruction. Am Rev Respir Dis.
breathing is their chronic baseline. Roughly 50% of patients with ƒ/V t 1987;136:872-879.
of 100 to 125 breaths/min per liter can be successfully extubated. 73
In these relatively rare situations, extubation should not be performed
casually. We consider “breaking the rules” outlined in this chapter only REFERENCES
after numerous failed trials of unassisted breathing and after treating
reversible causes of failure. The clinical risks associated with failure and Complete references available online at www.mhprofessional.com/hall

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