Electrical activity of the diaphragm during extubation readiness testing in critically ill children.
OBJECTIVE
To investigate the electrical activity of the diaphragm during extubation readiness testing.


METHODS
Prospective observational trial.


METHODS
A 29-bed medical-surgical pediatric intensive care unit.


METHODS
Mechanically ventilated children between 1 month and 18 yrs of age.


METHODS
Twenty patients underwent a standardized extubation readiness test using a minimal pressure support ventilation strategy. A size-appropriate multiple-array esophageal electrode (electrical diaphragmatic activity catheter), which doubled as a feeding tube, was inserted. The electrical diaphragmatic activity, ventilatory parameters, and spirometry measurements were recorded with the Servo-i ventilator (Maquet, Solna, Sweden). Measurements were obtained before the extubation readiness test and 1 hr into the extubation readiness test.


RESULTS
During extubation readiness testing, the ratio of tidal volume to delta electrical diaphragmatic activity was significantly lower in those patients who passed the extubation readiness test compared to those who failed the extubation readiness test (extubation readiness test, pass: 24.8 ± 20.9 mL/μV vs. extubation readiness test, fail: 67.2 ± 27 mL/μV, respectively; p = .02). Delta electrical diaphragmatic activity correlated significantly with neuromuscular drive assessed by airway opening pressure at 0.1 secs (before extubation readiness test: r = .591, p < .001; during extubation readiness test: r = .682, p < .001). Eight out of 20 patients had ventilator dys-synchrony identified with electrical diaphragmatic activity during extubation readiness testing.


CONCLUSIONS
Patients who generate higher diaphragmatic activity in relation to tidal volume may have better preserved diaphragmatic function and a better chance of passing the extubation readiness test as opposed to patients who generate lower diaphragmatic activity in relation to tidal volume, indicating diaphragmatic weakness. Electrical activity of the diaphragm also may be a useful adjunct to assess neuromuscular drive in ventilated children.
Department of Anesthesiology, Perioperative and Pain Medicine, Children's Hospital, Boston, MA, USA. gerhard.wolf@childrens.harvard.edu
Gerhard K
GK
Wolf
Brian K
BK
Walsh
Michael L
ML
Green
John H
JH
Arnold
D000293:Adolescent; D060666:Airway Extubation; D002648:Child; D002675:Child, Preschool; D003964:Diaphragm / Q000294:innervation*; D004566:Electrodes; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015278:Intensive Care Units, Pediatric; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013147:Spirometry; D015300:Ventilator Weaning