Chaturvedi R R, Lincoln C, Gothard J W, Scallan M H, White P A, Redington A N, Shore D F
Department of Paediatric Cardiology, Royal Brompton Hospital, Imperial College of Science, Technology, and Medicine, London, United Kingdom.
J Thorac Cardiovasc Surg. 1998 Jan;115(1):77-83. doi: 10.1016/s0022-5223(98)70446-5.
Quantification of myocardial injury after the simplest pediatric operations by load-independent indices of left ventricular function, using conductance and Mikro-Tip pressure catheters (Millar Instruments, Inc., Houston, Tex.) inserted through the left ventricular apex.
Sixteen infants and children with intact ventricular septum undergoing cardiac operations had left ventricular function measured, immediately before and after bypass. Real-time pressure-volume loops were generated by conductance and Mikro-Tip pressure catheters placed in the long-axis via the left ventricular apex, and preload was varied by transient snaring of the inferior vena cava.
Good quality pressure-volume loops were generated in 13 patients (atrial septal defects, n = 11; double-chambered right ventricle, n = 1; supravalvular aortic stenosis, n = 1; age 0.25 to 14.4 years, weight 3.1 to 46.4 kg). Their mean bypass time was 41 +/- 14 minutes and mean aortic crossclamp time 27 +/- 11 minutes. End-systolic elastance decreased by 40.7% from 0.34 +/- 0.17 to 0.21 +/- 0.15 mm Hg-1.ml-1.kg-1 (p < 0.001). There were no significant changes in the slope of the stroke work-end-diastolic volume relationship, end-diastolic elastance, time constant of isovolumic relaxation, and normalized values of the maxima and minima of the first derivative of developed left ventricular pressure.
Load-independent indices of left ventricular function can be derived from left ventricular pressure-volume loops generated by conductance and Mikro-Tip pressure catheters during the perioperative period in infants and children undergoing cardiac operations. Incomplete myocardial protection was demonstrated by a deterioration in systolic function after even short bypass and crossclamp times.
通过左心室功能的负荷独立指标，使用经左心室尖插入的电导和微尖端压力导管（Millar Instruments, Inc., 休斯顿，德克萨斯州），对最简单的小儿手术后的心肌损伤进行量化。
16例室间隔完整的婴幼儿和儿童在心脏手术中，在体外循环前后测量左心室功能。通过经左心室尖沿长轴放置的电导和微尖端压力导管生成实时压力-容积环，并通过短暂钳夹下腔静脉来改变前负荷。
13例患者（房间隔缺损，n = 11；双腔右心室，n = 1；主动脉瓣上狭窄，n = 1；年龄0.25至14.4岁，体重3.1至46.4 kg）生成了高质量的压力-容积环。他们的平均体外循环时间为41±14分钟，平均主动脉阻断时间为27±11分钟。收缩末期弹性从0.34±0.17降至0.21±0.15 mmHg-1.ml-1.kg-1，下降了40.7%（p < 0.001）。每搏功-舒张末期容积关系的斜率、舒张末期弹性、等容舒张时间常数以及左心室压力一阶导数的最大值和最小值的归一化值均无显著变化。
在接受心脏手术的婴幼儿和儿童围手术期，可通过电导和微尖端压力导管生成的左心室压力-容积环得出左心室功能的负荷独立指标。即使体外循环和阻断时间较短，收缩功能的恶化也表明心肌保护不充分。
