PURPOSE: Myocardial ischemia-reperfusion (IR) injury can result in major complications during the perioperative period. Experimental evidence demonstrates that inhaled volatile anesthetic administration enhances the recovery of the post-ischemic myocardium and reduces infarction size. Volatile anesthetics are rarely administered as the sole anesthetic agent and are rather administered in combination with other medications to facilitate amnesia and analgesia. There are few studies assessing 24 hours of in vivo reperfusion following coronary ischemia in the rat model.
METHODS: Male Long-Evans rats were anesthetized via intraperitoneal injection of ketamine and xylazine (IP injection) and underwent two surgeries. The first survival surgery employed the occlusion of a major coronary artery to induce cardiac damage followed by 24 hours of in vivo reperfusion. The second non-survival surgery consisted of cardiac harvesting. The experimental group (SEV) received 1% inhaled sevoflurane (n=6) for twenty minutes prior to induction of ischemia. Postoperative cardiac damage was assessed by the size of the infracted area (MI) over the total area at risk (AAR). The infracted area and AAR were determined by staining with 1% triphenyl-tetrazolium chloride (TTC) and 2% Evans blue dye. The area not at risk or the viable myocardium stained blue, the area at risk for infarction appeared red plus the infarcted area within the area at risk appeared grey (AAR). The infarcted area was calculated as percentage of total area affected (MI/AAR).
RESULTS: Sevoflurane treated rats had significantly larger MI/AAR scores (0.33±0.09) than did rats that received ketamine alone (CTRL) (0.17±0.12), p=0.027. See Figure 1.
CONCLUSION: The MI/AAR score following coronary ischemia followed by 24 hours of in vivo reperfusion is not decreased by sevoflurane administration when preceded by IP ketamine anesthesia in the rat model.
CLINICAL IMPLICATIONS: Further research on combinations of medications utilized in clinical practice on cardioprotective outcomes is warranted.
DISCLOSURE: Roberta Reedy, None.