Related Experiment Videos
Breathing measurement reduces false-negative classification of tachypneic preextubation trial failures
C B DeHaven1, O C Kirton, J P Morgan
1Division of Surgical Critical Care, Department of Surgery, University of Miami School of Medicine, Ryder Trauma Center, FL, USA.
Objectives:
There is increased awareness of imposed work of breathing contributing to apparent ventilatory dependency. This study evaluates the impact of tachypnea as an indicator of ventilatory failure during a room air-5 cm H2O continuous positive airway pressure, spontaneous breathing, preextubation trial when associated with increased imposed work of breathing.
Design:
Prospective, descriptive, 1-yr data collection.
Setting:
University hospital trauma intensive care unit (ICU).
Patients:
Mechanically ventilated trauma ICU patients surviving to discharge.
Intervention:
Patients were weaned to minimal mechanical ventilator support and underwent a 20-min room air-continuous positive airway pressure preextubation trial (FIO2 = 0.21, continuous positive airway pressure = 5 cm H2O [0.5 kPa]). When passed (PaO2 >/= 55 torr [>/= 7.3 kPa], PaCO2 /= 7.35, respiratory rate 1.1 joule/L, imposed work of breathing was measured, and if residual "physiologic" work of breathing (patient work of breathing minus imposed work of breathing) was
Measurements And Main Results:
Of 589 extubations, 105 (18%) were classified as false negatives based on a preextubation rate of > 30 breaths/min. Of these, 97 were successfully extubated despite tachypnea ranging from 32 to 56 breaths/min, when combined with either a patient work of breathing
Conclusions:
Tachypnea as a marker of respiratory distress is sensitive, but is not sufficiently specific to be used as a criterion in preextubation trials. Reliance on tachypnea as a preextubation trial failure criterion is likely to prolong intubation and ventilatory support for a large number of patients. Patient risks, determined by the extubation failures and reintubation rate, are the same.