The authors conducted a two-part study to determine whether transcutaneous
oxygen pressure (TcPO (2)) and transcutaneous
carbon dioxide pressure (TcPCO (2)) can be used to monitor flap viability after
transplantation. The first part was an animal study in which TcPO (2) and TcPCO (2) were measured in 10 epigastric
island flaps subjected to arterial or venous
ischemia. The second part was a clinical study in which both were measured in 27 free skin flaps. In the experimental study, TcPO (2) decreased to nearly 0 mmHg after 10 minutes of arterial and venous
ischemia. TcPCO (2) increased to 100 mmHg after 60 minutes of either type of
ischemia. In the clinical study, congestion was suspected in six flaps on the basis of clinical signs alone. Three congested flaps with TcPCO (2) more than 90 mmHg were selected for intervention. The remaining three congested flaps, with TcPCO (2) 80 mmHg or less, survived completely without further treatment. The TcPO (2) of all treated flaps and of the six flaps not requiring further treatment was 0 mmHg. Results of experimental study indicate that TcPO (2) is more sensitive than TcPCO (2) to flap
ischemia. However, results of clinical study suggest that it is very hard to distinguish congested flaps from healthy flaps by TcPO (2) alone. The authors believe that a congested flap with a TcPCO (2) more than 90 mmHg requires further treatment.