[1] KUOPIO UNIV HOSP, DEPT INTENS CARE, KUOPIO, FINLAND
[2] KUOPIO UNIV HOSP, DEPT MED, KUOPIO, FINLAND
[3] UNIV HELSINKI, CENT HOSP, DEPT ANESTHESIOL, SF-00100 HELSINKI 10, FINLAND
[4] UNIV TURKU, CENT HOSP, DEPT ANESTHESIOL, SF-20500 TURKU 50, FINLAND
[5] CENT HOSP CENT FINLAND, DEPT ANESTHESIOL, JYVASKYLA, FINLAND
[6] OULU UNIV, CENT HOSP, DEPT ANESTHESIOL, OULU, FINLAND