Intracapillary haemoglobin oxygenation and interstitial pO2 in venous flaps: An experimental study in rats

Abstract

In order to be able to objectively evaluate capillary perfusion of venous flaps, we created arterialised venous flaps, venous flow-through flaps, and unilateral pedicled venous island flaps in the epigastric vascular system of Wistar rats and determined their oxygen supply with two different methods. Interstitial pO2 was polarographically measured with a probe placed intracutaneously in the center of the 4 x 2.5 cm flaps and continuously recorded on a connected computer. Moreover, we also noninvasively determined the oxygenation of the intracapillary haemoglobin with a micro-lightguide spectrophotometer. The statistical evaluation showed comparable results for both measurement methods: Arterialised venous flaps had a better oxygen supply with a pO2 of 16 mmHg and an Hb oxygenation of 23% than the other types of venous flaps, but they have a poorer oxygen supply than conventionally perfused flaps (pO2: 24 mmHg, Hb oxygenation: 30%). Venous flow-through flaps (pO2: 9 mmHg, Hb oxygenation: 17%) and unilateral pedicled venous island flaps had a significant better oxygen supply than skin flaps without any vascular connection. The results show that the capillary system in all types of venous flaps is reached by some of the inflowing oxygenated haemoglobin over the entire flap surface to different degrees.

Autonomization of epigastric flaps in rats

“…The Hb level and blood flow have been already discussed in the literature, as the hemoglobin concentration has become an accepted predictive variable of flap outcome 17–21. The blood flow predicted for thromboembolism was found to be a predictor of flap loss due to surgical complications and a high re‐exploration rate 5, 6, 22.…”

Assessment of Tissue Perfusion Following Conventional Liposuction of Perforator-Based Abdominal Flaps

“…Using this device, the oxygen supply to the microcirculation of blood-perfused tissues can be determined. The O2C system presents more precise data on local oxygen supply compared with measurement of tissue partial oxygen pressure, which remains constant during changes in capillary blood flow rate or oxygen consumption [20]. Flow was demonstrated to be a better predictor of tissue perfusion while rHb and SO 2 failed to predict tissue necrosis [21].…”

Micro-lightguide spectrophotometry for tissue perfusion in ischemic limbs

“…Previous investigations have been made using O2C measurements. Measurements were made in the following: heart, 5 brain, 6 skin flaps, 7,8 the nerves of diabetic patients, 9 the optic nerve, 10 in models with venous hypertension, 11 in determination of mitochondrial metabolism, 12 and to assess the effect of hemodialysis on skin's microcirculation. 13 Also as mentioned, the method's ability to predict ulcer healing in patients with diabetes has been studied, 14,15 as well as the method's ability to predict healing after amputation.…”