Comparison of physiological responses to spontaneous breathing trials with a T-tube and low-level pressure support.
Previous studies have shown that spontaneous breathing trials (SBT) with a T-tube or low-level pressure support are comparable. However, low-level pressure support may overestimate the ability of a patient to sustain spontaneous breathing, resulting in premature extubation. Understanding factors contributing to different responses by patients to the two SBT methods aids in clarifying the limitation of using low-level pressure support for SBT. We performed a prospective observational study in 80 consecutive adult patients with mechanical ventilation to identify the factors contributing to different responses of a patient to the two SBT methods. The 80 patients underwent both a T-tube trial and pressure support ventilation of 6 cmH2O (PS-6) on the day of extubation. Stratified analysis was used to evaluate the effects of age, respiratory compliance and resistance, PaO2/FiO2 ratio and underlying disease on post-SBT responses. Comparing the responses to a T-tube trial and PS-6, the patients with old age, poor pulmonary compliance (≤40 ml/cmH2O) and chronic obstructive pulmonary disease had a higher heart rate (difference [95% CI]: 4 [0,8], 5 [2,9], 5 [0,10] beats/minute, respectively) and systolic blood pressure (10 [4,16], 11 [5,16], 7 [0,13] mmHg, respectively) after the T-tube trial. In conclusion, this research shows that old age and impaired respiratory mechanics contribute to different responses to spontaneous breathing trials with a T-tube and low-level pressure support. Further studies are needed to compare the effectiveness of the two SBT methods in predicting successful extubation in such patient groups.
Department of Internal Medicine and Traumatology, National Taiwan University Hospital and Medical College, Taipei, Taiwan.
S Y
SY
Ruan
H D
HD
Wu
Y W
YW
Kuo
P H
PH
Kuo
C T
CT
Huang
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D010100:Oxygen / Q000008:administration & dosage / Q000378:metabolism; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology / Q000628:therapy; D012121:Respiration, Artificial / Q000379:methods*; D015656:Respiratory Mechanics / Q000502:physiology*; D012307:Risk Factors; D015300:Ventilator Weaning / Q000379:methods*
D010100:Oxygen