Real-time intraoperative detection of tissue hypoxia in gastrointestinal surgery by wireless pulse oximetry.
OBJECTIVE
Dehiscence or leakage after bowel anastomoses is associated with high morbidity and mortality. Perfusion and local tissue oxygenation (StO2), independent of systemic oxygen saturation, are fundamental determinants of anastomotic viability. Because current technology is limited for monitoring local StO2 at bowel anastomoses, our goal was to construct a wireless pulse oximeter (WiPOX) to monitor real-time intraoperative tissue oxygenation, permitting identification of compromised anastomotic perfusion.


METHODS
We have: (a) designed a handheld device capable of real-time monitoring of serosal and mucosal StO2 through endoscopic ports with wireless data transmission to standard intraoperative monitors, (b) constructed the WiPOX using materials meeting FDA regulations for intraoperative use and reuse, (c) performed accuracy testing in humans by comparing the WiPOX to standard pulse oximeters, and (d) tested WiPOX efficacy for detecting early tissue hypoxia in stomach, intestines, and kidneys in anesthetized rats and swine.


RESULTS
In humans, WiPOX demonstrated accuracy within 3% compared with commercially available pulse oximeters. Application of the WiPOX in rats and swine demonstrated normal serosal and mucosal StO2 and pulse rates in healthy small bowel and stomach. Within 30 s of compromised perfusion, the WiPOX detected bowel hypoxia over a wide range of oxygen saturation (p<0.005). A greater degree of hypoxia was detected in mucosal versus serosal measurements during early ischemia, despite normal appearance of tissue. The onboard sensor-processor unit permitted noninvasive pulse oximetry and integration with current intraoperative monitoring. The contact pressure-sensing head allowed for consistent, high-quality StO2 waveform readouts despite the presence of body fluids.


CONCLUSIONS
We have constructed, validated, and successfully tested a novel wireless pulse oximeter capable of detecting intraoperative tissue hypoxia in open or endoscopic surgery. This device will aid surgeons in detecting anastomotic vascular compromise and facilitate choosing an ideal site for bowel anastomosis by targeting well-perfused tissue with optimal healing capacity.
Division of Thoracic Surgery, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.
Elliot L
EL
Servais
Nabil P
NP
Rizk
Luiz
L
Oliveira
Valerie W
VW
Rusch
Marom
M
Bikson
Prasad S
PS
Adusumilli
D057868:Anastomotic Leak / Q000175:diagnosis; D000818:Animals; D015687:Cell Hypoxia; D013505:Digestive System Surgical Procedures; D005260:Female; D006801:Humans; D007422:Intestines / Q000098:blood supply; D007668:Kidney / Q000098:blood supply; D016343:Monitoring, Intraoperative; D010092:Oximetry / Q000295:instrumentation*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013270:Stomach / Q000098:blood supply; D034421:Sus scrofa