The influence of stellate ganglion transcutaneous electrical nerve stimulation on signal quality of pulse oximetry in prehospital trauma care.
BACKGROUND
Accurate monitoring of the peripheral arterial oxygen saturation has become an important tool in the prehospital emergency medicine. This monitoring requires an adequate plethysmographic pulsation. Signal quality is diminished by cold ambient temperature due to vasoconstriction. Blockade of the stellate ganglion can improve peripheral vascular perfusion and can be achieved by direct injection or transcutaneous electrical nerve stimulation (TENS) stimulation. We evaluated whether TENS on the stellate ganglion would reduce vasoconstriction and thereby improve signal detection quality of peripheral pulse oximetry.


METHODS
In our study, 53 patients with minor trauma who required transport to the hospital were enrolled. We recorded vital signs, including core and skin temperature before and after transport to the hospital. Pulse oximetry sensors were attached to the patient's second finger on both hands. TENS of the stellate ganglion was started on one side after the beginning of the transport. Pulse oximeter alerts, due to poor signal detection, were recorded for each side separately.


RESULTS
On the hand treated with TENS we detected a significant reduction of alerts compared to the other side (mean alerts TENS 3.1 [1-15] versus control side 8.8 [1-28] P < 0.05). The duration of dropouts was shorter as well (mean duration TENS 77 [16-239] s versus control side 333 [78-1002] s).


CONCLUSIONS
The data indicate that blockade of the stellate ganglion with TENS improves signal quality of pulse oximeters in the prehospital setting.
Barker
Renate
R
Department of Anesthesia and General Intensive Care, Medical University of Vienna, Vienna, Austria.
Lang
Thomas
T
Hager
Helmut
H
Steinlechner
Barbara
B
Hoerauf
Klaus
K
Zimpfer
Michael
M
Kober
Alexander
A
D000368:Aged; D000369:Aged, 80 and over; D004560:Electricity; D004632:Emergency Medical Services / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010092:Oximetry / Q000379:methods*; D011446:Prospective Studies; D013233:Stellate Ganglion / Q000502:physiology*; D004561:Transcutaneous Electric Nerve Stimulation / Q000379:methods*; D014947:Wounds and Injuries / Q000503:physiopathology / Q000628:therapy