Effects of PEEP on Residual Vascularization in Oesophageal Substitution Gastroplasty by Surface Oximetry-Capnometry and Photoplethysmography

Abstract

Objective: To evaluate the effects of positive end-expiratory pressure (PEEP) on residual vascularization in gastric tubes for oesophageal replacement. Design: Experimental open study. Materials: Eleven mongrel dogs. Methods: Intestinal parietal blood flow was evaluated by photoplethysmography (PPG) and measurement of surface oxygen (PsO₂) and carbon dioxide (PsCO₂) tensions under basal conditions. After Akiyama’s tubular gastroplasty, three levels of PEEP were administered. At each level, fluids were infused to counter the drop in cardiac output. PPG, surface gas tensions, arterial pressure, cardiac output and arterial blood gas tensions were monitored. Control sections of the bowel were also monitored by PPG. Results: Cardiac output dropped for each level of PEEP and returned to basal levels on volume restabilization and on removal of PEEP. Central venous pressure and pulmonary arterial and capillary pressures increased for each level of PEEP and only returned to basal levels on removal of PEEP. PsO₂ values dropped for each level of PEEP and returned to basal levels on volume restabilization and on removal of PEEP. PsCO₂ levels rose, and PPG wave amplitude dropped, for each level of PEEP; these two variables only returned to basal levels on removal of PEEP. PPG values for the control sections reflected those of the anastomotic area. Conclusions: PEEP affects surface oxygen values at the level of the gastroplasty by means of its effect on cardiac output. PEEP also creates a venous return compromise and PPG wave amplitude and surface carbon dioxide values are related to this compromise. All three variables could be significant in anastomotic wound healing.

Evaluation of Splanchnic Perfusion and Oxygenation during Positive End-Expiratory Pressure Ventilation in Relation to Subcutaneous Tissue Gases and pH

“…Serosal oxygen tension is more likely to reflect the oxygen tension of the gut wall, thus indirectly predicting anastomotic healing. In fact measurements of serosal tissue PO 2 have been demonstrated to assess viability of anastomoses in different parts of the gastrointestinal tract [26][27][28][29][30]. Measured perianastomotic PserO 2 values of 25 mm Hg or less predicted anastomotic leakage in a rabbit model [28].…”

Effect of Intraoperative PEEP Application on Colonic Anastomoses Healing: An Experimental Animal Study

“…[21][22][23][24][25] Further, 10 cm of H 2 O PEEP has been assumed to be the limit for splanchnic blood flow reduction, and levels of 15 to 20 cm of H 2 O PEEP have frequently been found to be associated with reduced splanchnic circulation in both animals and humans. [26][27][28] Fig . 3 The Mann-Whitney U test demonstrates that the arterial SO 2 positively correlates with PEEP during surgery (P , 0.05).…”

“…35,36 Local intestinal oxygenation is also said to be independent of systemic PO 2 . 27 On the other hand, higher systemic PO 2 levels are also reported to improve tissue oxygenation and increase collagen deposition. 37,38 Increased PO 2 improves tissue oxygenation and enhances wound healing.…”

Influence of route of gastric transposition on oxygen supply at cervical oesophagogastric anastomoses

“…Some data suggest that the gastric microcirculation after retrosternal pull‐up might be inferior to that after orthotopic pull‐up, resulting in a higher rate of anastomotic leakage and stricture11, 16. Attempts have been made to determine microcirculatory changes in the stomach by employing non‐invasive techniques such as laser Doppler flowmetry3, 17–20, surface oximetry–capnography21, 22, photoplethysmography21 and mucosal pH monitoring23. These studies generally involved taking measurements at particular times during surgery, allowing a direct or indirect evaluation of perfusion and/or oxygen supply.…”