Hemodynamics of the oral mucosa during cooling: A crossover clinical trial

Oral cryotherapy is used to prevent the onset of oral mucositis, a common and debilitating adverse effect following cancer chemotherapy. A protective mechanism associated with oral cooling is thought to be mediated through reduced tissue microcirculation. The aim of the present study was to examine the underlying mechanism associated with oral mucosal cooling by measuring oral microcirculation and tissue oxygen saturation after cooling with ice chips (IC) and an intraoral cooling device (ICD).

In a single-center randomized crossover study, 10 healthy volunteers were assigned (1:1) randomly to the order in which the two intraoral cooling procedures (IC/ICD) were to be commenced. On day 1, half of the study participants started with IC and then crossed over to intraoral cooling with the ICD on day 2, while the other half of the participants undertook the same two procedures in the reverse order. Total and functional capillary density (T/FCD) and tissue oxygen saturation (StO₂) measurements were obtained at baseline and 30 min following oral cooling.

Following 30 min of oral cooling, a statistically significant difference was found for FCD between IC and ICD (percentage points; +2 vs. -13; p < 0.05). A statistically significant decrease in StO₂ was observed with both IC and ICD (%; 13 vs. 10) after 30 min of cooling as compared to baseline (p < 0.05). As for the participants' preference the ICD was preferred over IC by 9 out of 10 participants (p = 0.021).

Both microcirculation parameters and tissue oxygen saturation are altered in conjunction with oral cooling, indicating their potential mechanistic contribution towards cryoprevention of oral mucositis.