Weaning and Decannulation

Mechanical ventilation is associated with several complications including respiratory muscle weakness, ventilator-induced lung injury, trauma to the upper airway, and ventilator-associated pneumonia (14,15). Therefore, minimizing the duration of invasive ventilatory 

The term weaning encompasses two different stages with specific requirements (i) discontinuation of invasive ventilation and (//) removal of the artificial airway (Fig. 1). The first step is to assess the potential to discontinue invasive ventilation either to autonomous breathing or to NTV support. If the patient fulfills the necessary criteria, a formal spontaneous breathing test (SET) is performed. If successful, the patient can then be disconnected from the ventilator, or in case of a failed SET transitioned to NIV. The next step includes removal of the artificial airway, provided secretion management or upper airway obstruction is not an issue. 

As the underlying condition improves, there should be daily assessment of the potential for discontinuing invasive ventilation. Criteria include adequate mentation, absence of fever or anemia, cessation of neuromuscular-blocking agents and sedatives, hemodynamic stability, correction of electrolyte and metabolic disorders, and adequate oxygenation (5,14-17, 27,28) (Fig. 1). After these criteria are met an SET should be considered. 

Weaning failure increases the risk of myocardial ischemia, left ventricular dysfunction, and pulmonary hypertension (27,29). In a prospective cohort study, Epstein et al. (30) evaluated medical outcomes of 42 patients reintubated after an unsuccessful extubation attempt. They noted an increase in mortality, duration of ICU and hospital stay, dependence on ventilatory support, and requirements for long-term care among these patients. Predicting failure to wean has been disappointing (15,27,31), especially among patients with neuromuscular disease who often perform better than expected (13,32). 

Meade et al. (31) noted that the best predictors of successfiil extubation were respiratory rate 38 breaths/min (sensitivity, 88% specificity, 47%), rapid shallow breathing index 105 breaths/L/min (sensitivity, 65-96% specificity, 0-73%), and Po.i/Pimax 0.09 (sensitivity, 69% specificity, 96%). Except for the maximal occlusion pressure most parameters achieved 

---

Following implementation of the long-term phase of the rehabilitation framework, she was weaned and decannulated within 21 days. Her total LOS in the ICU was 106 days at a cost of 159,000 ( 301,221). She was transferred to the ward and went home 14 days later on an individual pulmonary rehabilitation program. At six months Sarah was back at work full time and has had no further physiological or psychological problems. Appendix 1 shows Sarah s specific rehabilitation and weaning plan. 

Within three weeks of starting rehabilitation Sarah was weaned and decannulated. Table A1 shows Sarah s exercise tolerance over the three-week period. 

Cheitcoff et al. (14) described patients from ICUs referred to LTMVUs. Between 1998 and 2002, out of 112 patients, 50 were weaned and decannulated. Their diagnoses included COPD (n = 23), NMD (n = 13), postoperative conditions (n = 9), and non-COPD pulmonary disease (n = 5). Planells et al. (15) also reported their experience with an LTMVU. Between 1997 and 2001, both NIPPV and TIPPV were established in a total of 62 patients. Their diagnoses included COPD 26%, CNS disease 35%, NMD 18%, spinal cord injury 6.6%, postoperative conditions 5%, and others 10%. Patients were enrolled for 64 days (9-150 days) after starting ventilation. Most candidates (n = 43) were identified in the category of weanable, some were clearly unweanable (n = 8) and others were using NIPPV (n = 11). Sixty five percent (n = 28) of the weanable patients were successfully weaned. 

Following implementation of the rehabilitation framework, May was weaned from MV and decannulated within 21 days. Her total LOS was 72 days at a cost of 108,000 (S204,588). She was transferred to the ward but waited for another 33 days before being transferred to a rehabilitation facility, where she stayed for 21 days. Now, one year later. May lives at home, cares for herself, socializes, and is making good progress. 

Bach JR, Goncalves M. Ventilator weaning by lung expansion and decannulation. Am J Phys Med Rehabil 2004 83(7) 560-568. 

In this chapter we will discuss recommendations from the hterature regarding dec-aruiulation as well as our personal clinical experience. We will comment on the pathophysiology of ventilator dependence, the determination of candidates for weaning from ventilation and tracheostomy, and a stepwise approach to decannulation. Lastly, we will discuss the choices of noninvasive ventilatory supports and techniques that clinicians may utilize, such as lung volume recruitment (LVR), assisted coughing and mechanical airway clearance. 

---