Hong Ko

Head position for facilitating the superior vena caval placement of catheters during right subclavian approach in children

Objective To evaluate the effect of head position as a method to facilitate the superior vena caval placement of catheters during right subclavian catheterization in children. Design Prospective, randomized, clinical trial. Setting Department of anesthesiology, university hospital. Patients One hundred sixty-eight pediatric patients, aged <8 yrs, undergoing simple cardiac surgery or pediatric general surgery. Interventions At operation, the patients were assigned by the stratified randomization for age to one of the four groups (n = 42 each): when the patients turned their heads away from the puncture side, this was away-turning group; when turned toward the puncture side, toward-turning group; when lateral-flexed (tilted) away from the puncture side, away-lateral-flexion group; and when lateral-flexed toward the puncture side, toward-lateral-flexion group. Each group was divided into two subgroups depending on the age: infant (n = 24 each) and young children (>12 months; n = 18 each). Measurements and Main Results Right infraclavicular subclavian catheterization, using the Seldinger technique, was attempted. After catheterization, a simple chest radiograph was used to identify the location of catheter tip. There was no difference in age and body weight between the groups. Only in infants was the successful placement rate of toward-lateral-flexion group (92%) higher than that of the other three groups (54% [away-lateral-flexion], 63% [away-turning], or 54% [toward-turning]), and there was no difference among the others. Conclusion In infants, tilting the head toward the catheterization side can reduce the incidence of catheter malposition during the right subclavian approach.

Continuous mixed venous oxygen saturation, not mean blood pressure, is associated with early bupivacaine cardiotoxicity in dogs

PurposeTo investigate changes of continuous mixed venous oxygen saturation (cSvO2) and mean arterial blood pressure (MBP) in dogs with bupivacaine-induced cardiac depression.MethodsBupivacaine was infused into pentobarbital-anesthetized mongrel dogs (n = 8) at a rate of 0.5 mg·kg−1min·−1 until the MBP was 40 mmHg or less (end of bupivacaine infusion; BIE). The infusion time was divided into the early period, first 30 min of bupivacaine infusion and the late period, which was from 30 min of bupivacaine infusion until BIE. cSvO2 was monitored using a fibreoptic pulmonary artery catheter, and MBP and cardiac output (CO) were measured every ten minutes after the initiation of bupivacaine infusion. Arterial blood gas, serum electrolyte and bupivacaine concentration were measured simultaneously. The relationships between CO and cSvO2, and of COvs MBP were compared by regression analysis in the early and late periods.ResultsThe Pearson’s correlation coefficients between CO and cSvO2 were 0.782 (P = 2.1 × 10−7) in the early period and 0.824 (P = 1.3 × 10−6) in the late period. The correlation coefficients between CO and MBP were 0.0 19 (P = 0.921) in the early period and 0.799 (P = 4.8 × 10−6) in the late period.ConclusionsCSvO2, but not MBP is associated with CO changes in bupivacaine-induced cardiac depression during the early period of bupivacaine intoxication. Decrease of MBP with low cSvO2 observed during the late period might imply severe cardiac depression induced by bupivacaine infusion.RésuméObjectifExaminer les modifications de ia saturation continue en oxygène du sang veineux mêié (ScO2v) et de la tension artérielle moyenne (TAM) chez des chiens qui présentent une dépression cardiaque induite par ia bupivacaïne.MéthodeLa bupivacaïne a été administrée chez des chiens de race commune (n = 8), anesthésiés au pentobarbital, selon un débit de 0,5 mg·kg−1·min−1 jusqu’à ce que la TAM soit de 40 mmHg ou moins (fin de ia perfusion de bupivacaïne; FPB). Le temps de perfusion a été divisé en une période précoce pour tes 30 premières min et tardive, à partir de 30 min jusqu’à la FPB. La ScO2v a été enregistrée avec un cathéter artériel pulmonaire fibroscopique. La TAM et te débit cardiaque (DC) ont été mesurés toutes les dix minutes après ie début de ia perfusion de bupivacaïne. La gazométrie du sang artériel, la concentration sérique d’électrolytes et de bupivacaïne ont été mesurées simultanément. La relation entre le CO et la ScO2v, et entre le CO et la TAM a été comparée par une analyse de régression pendant les deux périodes de perfusion déterminées.RésultatsLes coefficients de corrélation de Pearson entre ie CO et la ScO2v ont été de 0,782 (P = 2,1 × 10−7) pendant la période précoce de la perfusion et de 0,824 (P = 1,3 × 10−6) pendant la période tardive. Les coefficients de corrélation entre le CO et la TAM ont été de 0,019 (P = 0,921) pendant la période précoce et de 0,799 (P = 4,8 × 10−6) pendant la période tardive.ConclusionLa ScO2v, mais non la TAM, est associée aux variations de CO de la dépression cardiaque induite par la bupivacaïne pendant la période précoce de l’intoxication à la bupivacaïne. Une baisse de la TAM, accompagnée d’une faible ScO2v, observée pendant la période tardive, peut correspondre à une dépression cardiaque sévère induite par la perfusion de bupivacaïne.