Young-Kyun Choe

Effect of remifentanil on QT dispersion

BACKGROUND QT dispersion (QT(d)) is an indirect measure of the heterogeneity of ventricular repolarization and can be used as a risk factor for complex ventricular arrhythmias. We measured the effect of remifentanil on QT(d) and heart-rate corrected QT dispersion (QT(cd)). METHODS Sixty ASA class I and II patients, who were between 20 and 60 years old, and who were scheduled for general anesthesia, were studied. After the patient entered the operating room, a 12 lead EKG recording was taken and intravenous infusion of remifentanil was started. The infusion rate was 0.1 microg/kg/min in group 1 and 0.2 microgram/kg/min in group 2. Another EKG recording was taken 10 minutes after infusion had started. RESULTS In both groups, QT(d) following remifentanil infusion was not significantly different than control values (76.6 +/- 23.3 ms vs 81.8 +/- 34.9 ms, P = 0.459 in group 1; 70.7 ms +/- 29.7 ms vs 73.7 ms +/- 37.1 ms, P = 0.734 in group 2). Neither was QT(cd): (83.2 ms +/- 25.2 ms vs 89.6 ms +/- 36.2 ms, P = 0.371 in group 1; 81.0 ms +/- 35.2 ms vs 83.4 ms +/- 40.9 ms, P = 0.829 in group 2). CONCLUSIONS Remifentanil infusion at a rate less than 0.2 microg/kg/min does not change QT(d) or QT(cd).

Uncontrollable hyperthermia in acute cerebral injury - A Case report -

A 39 year old man arrived at the hospital with semi-comatose state as a result of spontaneous intracerebral hemorrhage (ICH), intraventricular hemorrhage (IVH) and subarachnoid hemorrhage (SAH). For emergency craniectomy and hematoma removal, general anesthesia with desflurane and vecuronium was planned. Before the induction of anesthesia, the body temperature and end-tidal carbon dioxide (ETCO2) levels were 38.3degrees C and 38 mmHg, respectively. The body temperature and ETCO2 increased during surgery. After 2 hours of anesthesia, the temperature had increased to 41degrees C, despite bladder irrigation and body cooling. After 3 hours of anesthesia, the temperature reached 43.5degrees C and cardiac arrest developed. Cardiopulmonary resuscitation was attempted, but the patient expired.

Predictable normocapnoea in controlled ventilation of infants with Jackson Rees or Bain system

We have devised a formula for ventilator settings which would provide normal minute ventilation without rebreathing during controlled ventilation using a Jackson Rees or Bain system. As V T = V S + V F − V L, where V T = delivered tidal volume, V S = set tidal volume, V F = the volume of fresh gas entering during the inspiratory phase and V L = the lost volume due to the compliance of the system, V S was derived: V S = V L + V T × [1 − b/(1 + a)] where a = expiratory‐to‐inspiratory ratio and b = the ratio of fresh gas flow to the minute ventilation. It was evaluated in 62 infants. Arterial partial pressure of carbon dioxide (mean (SD)) was 4.6 (0.5) kPa (35 (4) mmHg) with a range of 3.42–5.78 kPa (26–44 mmHg). The 90th percentile was 5.1 kPa (39 mmHg). It is concluded that predictable normocapnoea can be conveniently achieved in infants in controlled ventilation with Jackson Rees or Bain system if our formula is applied.