Sigmoid colonic reflectance pulse oximetry and tonometry in a porcine experimental hypoperfusion shock model

Abstract

In contrast to the results of previous investigations, the sigmoid colonic pulse oximetry was not useful because the method proved to be overly sensitive and non-linear in relation to regional blood flow.

Transmittance photoplethysmography with near-infrared laser diodes in intra-peritoneal organs

“…Several publications have been devoted to the study of techniques based on optical principles for an objective evaluation of visceral perfusion and the viability of intra-peritoneal tissues and organs. These studies have been performed in patients (Ouriel et al 1988, Salo et al 1992, Garcia-Granero et al 1997, Delaney et al 1999, La Hei and Shun 2001, Crerar-Gilbert et al 2002 and animal models (Whitehill et al 1988, Vahl et al 1995, Uribe et al 1995, Avino et al 1995, Koga et al 2002, using photoplethysmography (Ouriel et al 1988, Whitehill et al 1988, Uribe et al 1995, Avino et al 1995, Garcia-Granero et al 1997, Crerar-Gilbert et al 2002 and pulse oximetry (Ouriel et al 1988, Salo et al 1992, Vahl et al 1995, Avino et al 1995, Yilmaz et al 1999, Delaney et al 1999, La Hei and Shun 2001, Koga et al 2002, Crerar-Gilbert et al 2002 in transmission (Ouriel et al 1988, Salo et al 1992, Avino et al 1995 or reflection mode (Vahl et al 1995, Garcia-Granero et al 1997, Yilmaz et al 1999, Koga et al 2002, Crerar-Gilbert et al 2002.…”

“…Despite the positive evidence of the authors regarding the usefulness of photoplethysmography and pulse oximetry, there are some reports which account for certain shortcomings (Whitehill et al 1988, Avino et al 1995, Delaney et al 1999, Koga et al 2002. Early authors (Whitehill et al 1988) pointed out that the detection threshold of photoplethysmography may be below the minimal flow requirements necessary for tissue viability and that the photoplethysmographic waveform should not be used as a reliable assurance of the ultimate viability of ischemic intestinal tissue.…”

“…Their results demonstrated that the use of pulse oximetry was not as easily reproduced as previously suggested. More recently, Koga et al (2002) concluded, after a study of 14 piglets with a reflectance probe, that sigmoid colonic endoluminal pulse oximetry may not be a suitable method for monitoring colonic ischemia. Almost at the same time, Crerar-Gilbert et al (2002) obtained measurable photoplethysmographic signals from the surface of the bowel (12 patients), the liver (eight patients) and the kidney (six patients), using a purpose-built reflectance probe with peak emissions at 665 nm (red) and 880 nm (infrared).…”