Page 213 - Clinical Application of Mechanical Ventilation

Airway Management in Mechanical Ventilation 179

monitored. Deteriorating vital signs and oxygen desaturation are signs of speaking
valve malfunction, severe airflow obstruction, or air leak.

EXTUBATION

Extubation should be done as soon as feasible. Early extubation not only provides im-
mediate relief to the patient, but also shortens the duration of a hospital stay, reduces
health care costs, and conserves resources (Cheng, 1995; Lichtenthal et al., 1995;
Velasco, 1995). In one study of patients undergoing coronary artery bypass grafting,
the average saving per patient was $6,000 in the early extubation group (Arom, 1995).

Predictors of Successful Extubation

A patient is ready for extubation after regaining airway reflexes and showing no
signs of cardiopulmonary distress. Strong productive coughs, small amount of
secretions, and hemoglobin level .10g/dL are good predictors of successful extuba-
tion (Khamiees, 2001). Other objective criteria for assessing a patient’s readiness for
extubation include the rapid shallow breathing index, blood gases, muscle strength,
and general cardiopulmonary signs.
Rapid shallow breathing index. The rapid shallow breathing (f/V ) index can be ob-
The patient should T
be allowed to breathe tained easily by measuring the breathing frequency and minute volume during
spontaneously for at least
three minutes before taking 1 min of spontaneous breathing (Epstein, 1995; Yang et al., 1991). f/V is calculated
T
measurements. Otherwise, by dividing the spontaneous breathing frequency per minute by the average tidal
the f/V T index may not reflect
the patient’s actual condition. volume in liters. A value of less than 100/min/L is highly predictive of successful
extubation outcome.
Other common indicators. Acceptable blood gases, ventilatory reserve, and general
Competent personnel cardiopulmonary signs, infrequent need for suctioning (.4 hours), being alert, and
and intubation supplies must SpO .95% are other useful indicators that may be used to guide the extubation
be readily available during 2
extubation. decision (Pronovost et al., 2002). These criteria and the rapid shallow breathing
index are very simple and easy to use. They are summarized in Table 6-10 along
with their respective methods of assessment.

Procedure

There should be no disagreement that extubation is easier than intubation. Nev-
The person who is ertheless, the person who is doing the extubation must be proficient in intubation
doing the extubation must be
proficient in intubation. as well. Since the criteria used for the extubation decision cannot predict a suc-
cessful outcome every time, one must anticipate the need for reintubation on short
notice. Intubation supplies must also be readily available during extubation.
Before extubation, the procedure is explained to the patient and the patient is posi-
tioned in a Fowler’s (semi-sitting) position. Hyperinflation and oxygenation are pro-
vided to the patient with a manual resuscitator via the ET tube. The ET tube is then
suctioned.

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