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Journal of Clinical Monitoring and Computing (2004) 18: 343345 C Springer 2005INITIAL TRANSCUTANEOUS PCO2 OVERSHOOT
WITH EAR PROBE AT 42 CSohei Kagawa, MD,1 Norimasa Otani, MD,1 Masayuki
Kamide, MD,1 Pierre-Alain Gisiger, Dipl. Phys.,2 Patrick
Eberhard, PhD,2 and John W. Severinghaus, MD3From the 1Department of Anesthesia, Atsugi City Hospital, Atsugi,
Kanagawa, Japan, 2Linde Medical Sensors AG, Basel, Switzerland,
3Department of Anesthesiology, University of California, San Francisco, CA, USA.Received June 24, 2004, and in revised form September 21, 2004.
Accepted for publication October 25, 2004.Address correspondence to Sohei Kagawa, Department of Anesthesia, Atsugi City Hospital 1-16-36 Mizuhiki, Atsugi-City, Kanagawa,
Japan 243-8588.E-mail: [email protected] important report related to this paper was found by one of us
in March 2005, showing a biphasic response of skin blood flow to
heating at 42 C, due to a previously unknown initial vasoconstrictive
response to heating, followed by a vasodilation mediated by nitride
oxide. Charkoudian, N. Skin blood flow in adult human thermoregulation: How it works, when it does not and why. Mayo Clinic Proc.
2003; 78: 603612.Kagawa S, Otani N, Kamide M, Gisiger P-A, Eberhard P, Severinghaus
JW. Initial transcutaneous PCO2 overshoot with ear probe at 42 c.J Clin Monit 2004; 18: 343345ABSTRACT. Objective. To investigate an unexpectedly high initial skin CO2 pressure with a new small earlobe probe heated
to 42 C containing both transcutaneous (tcPCO2) and pulse
oximeter saturation (SpO2) sensors. Methods. The probe was
mounted on the ear lobe of six patients during abdominal or
thoracic surgery and on several awake volunteers. The probe was
mounted on a cheek or forearm in two other volunteers. Patients were artificially ventilated under general anesthesia at constant end-expiratory PCO2. Results. In patients, at 8 3 min
after mounting, tcPCO2 peaked 5 mmHg higher than its final
value ( p = 0.0067, n = 6, paired t-test). After 25 min, tcPCO2
was not different from PaCO2 (arterial). Similar overshoots were
recorded with this device when mounted on the arm or cheek
and with a standard transcutaneous PCO2 probe set to 42 C,
mounted on the ear lobe, arm or chest of awake volunteers. In
two volunteers, we found that heating the sensor to 45 C for the
first 15 min on the ear, and then decreasing it...