Detection of hypoventilation during thoracoscopy: combined cutaneous carbon dioxide tension and oximetry monitoring with a new digital sensor.
BACKGROUND
Changes in Paco(2) have not been described during thoracoscopy under sedation-assisted local anesthesia. We hypothesized that hypoventilation might occur secondary to administration of sedatives and decreased ventilation in one lung.


OBJECTIVE
Prospectively measure cutaneous carbon dioxide tension (Pcco(2)) in addition to pulse oximetric saturation (Spo(2)) using a new combined digital sensor to examine the occurrence of hypoventilation during thoracoscopy under sedation-assisted local anesthesia.


METHODS
University hospital.


METHODS
Following validation studies, Pcco(2) was prospectively measured in 16 consecutive patients undergoing thoracoscopy under sedation-assisted local anesthesia using a combined digital earlobe sensor measuring Spo(2) (percentage) and Pcco(2) (millimeters of mercury). All patients received supplemental oxygen. Routine BP monitoring and Spo(2) was continued. Patients received IV hydrocodone, 5 mg, and intermittent boluses or IV midazolam and pethidine.


RESULTS
Mean baseline Pcco(2) measurement was 39.1 +/- 7.2 mm Hg (+/- SD) [range, 27.5 to 50.5 mm Hg], and peak measurement during the procedure was 52.3 +/- 10.3 mm Hg (range, 37.2 to 77 mm Hg) [p < 0.001]. Median and mean changes in Pcco(2) measurement from baseline were 13.0 mm Hg and 13.2 +/- 5.3 mm Hg (range, 5.5 to 27.8 mm Hg), respectively. Mean fall in Spo(2) during the procedure was 4.6 +/- 3.2% (range, 1 to 14%).


CONCLUSIONS
Thoracoscopy performed under sedation-assisted local anesthesia is associated with significant hypoventilation. Combined measurement of Spo(2) and Pcco(2) during thoracoscopy is a novel approach in the monitoring of ventilation, enhancing patient safety, and might allow to guide the administration of sedation in a better way.
Chhajed
Prashant N
PN
Division of Respiratory Medicine and Pulmonary Cell Research, University Hospital Basel, Petersgraben 4, CH-4031, Basel, Switzerland. PChhajed@uhbs.ch
Kaegi
Bruno
B
Rajasekaran
Rajeevan
R
Tamm
Michael
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000772:Anesthesia, Local; D001785:Blood Gas Monitoring, Transcutaneous / Q000295:instrumentation*; D016292:Procedural Sedation; D005260:Female; D006801:Humans; D006853:Hydrocodone / Q000008:administration & dosage / Q000009:adverse effects; D007040:Hypoventilation / Q000175:diagnosis*; D007262:Infusions, Intravenous; D007431:Intraoperative Complications / Q000175:diagnosis*; D008297:Male; D008614:Meperidine / Q000008:administration & dosage / Q000009:adverse effects; D008874:Midazolam / Q000008:administration & dosage / Q000009:adverse effects; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation*; D010092:Oximetry / Q000295:instrumentation*; D011446:Prospective Studies; D012307:Risk Factors; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013906:Thoracoscopy
D006853:Hydrocodone; D008614:Meperidine; D008874:Midazolam