Monitoring of whole-body hyperthermia with transesophageal echocardiography (TEE)

Abstract

Hyperthermia induces tumor cell death by a spectrum of tumor tissue changes. As whole-body hyperthermia (WBH) can cause cardiovascular complications, especially when cardiotoxic cytostatic agents are administered, invasive cardiovascular monitoring during WBH is necessary. WBH requires a great deal of expenditure and bears the risk of severe toxicity. Furthermore cardiovascular stress, alterations of cardiac index and systemic vascular resistance are major problems during WBH. The purpose of this prospective study was to evaluate cardiovascular changes in patients undergoing WBH under general anesthesia using transesophageal echocardiography (TEE) with special focus on left ventricular function.

Methods: Hemodynamic parameters were measured with standard monitoring and TEE at defined time points in 20 patients (ASA III) undergoing WBH: M37 (baseline, body temperature: 37°C) after induction of anesthesia, M39 during warming up (39°C), M41.8 at plateau level (41.8°C), M38 during cooling period (38°C).

Results: Invasive monitoring and TEE measurements showed signs of hyperdynamic circulation with significant increase of the heart rate (73.6 ± 13.7 min⁻¹ (M37), 104.6 ± 13.0 min⁻¹ (M41.8)) and significant decrease of mean blood pressure (74.9 ± 15.3 mmHg (M37), 65.3 ± 11.2 mmHg (M41.8)). Cardiac index (CI) nearly doubled and stroke volume index (SVI) increased significantly from M37 to M41.8. Cardiac contractility, fractional area change (FAC) and ejection fraction (EF) increased. At M38 CI, SVI, FAC and EF showed a tendency to decrease compared to M41.8 but remained elevated compared to M37.

Conclusion: Patients undergoing WBH showed typical signs of hyperdynamic circulation without impairment of left ventricle which could be monitored excellently by TEE. We recommend using TEE especially in patients with an increased cardiac risk.

• Whole-body hyperthermia
• cardiovascular changes
• transesophageal echocardiography