Emerson R J, Banasik J L
Intercollegiate Center for Nursing Education, Spokane, WA 99204.
Am J Crit Care. 1994 Jul;3(4):289-99.
Indirect/noninvasive blood pressure, heart rate and central venous pressure are frequently monitored hemodynamic parameters in postoperative cardiac surgery patients. No previous studies have explored the effect of lateral position on these variables in this population.
To determine differences in (1) blood pressure, central venous pressure, or heart rate measurements among postoperative cardiac surgery patients due to position (supine, 45 degrees right lateral, and 45 degrees left lateral), (2) responses to position between patients having cardiac surgery in which the myocardium was opened (valvular replacement) and those in which it was not (coronary artery bypass graft), and (3) responses to position between cardiac surgery patients having preoperatively diagnosed lung disease and those without lung disease.
Phlebostatic axis in lateral positions was determined by echocardiography and geometric diagrams prior to the initiation of data collection. Postoperative cardiac surgery patients (N = 120) were studied in the three positions in random sequences. In each position, simultaneous blood pressure measurements were obtained from each arm, and central venous pressure and heart rate were recorded.
Statistically significant differences were found in response to position in systolic and diastolic blood pressure, central venous pressure, and heart rate. Certain positions produced greater changes in selected variables, both in the total group and within specific subgroups. No differences were found between coronary artery bypass graft and valve (closed or opened myocardium) subgroups or between subgroups with and without lung disease.
Lateral positioning of postoperative cardiac surgery patients appears to cause no detrimental effects on indirect/noninvasive blood pressure or heart rate measurements. However, significant differences in central venous pressure may occur and supine positioning for determination of central venous pressure is recommended.
间接/无创血压、心率和中心静脉压是心脏手术后患者常用的血流动力学监测参数。此前尚无研究探讨侧卧位对此类患者这些变量的影响。
确定（1）心脏手术后患者因体位（仰卧位、右侧45度卧位和左侧45度卧位）导致的血压、中心静脉压或心率测量值的差异；（2）心肌切开的心脏手术患者（瓣膜置换术）和未切开心肌的患者（冠状动脉旁路移植术）对体位的反应差异；（3）术前诊断为肺部疾病的心脏手术患者和无肺部疾病患者对体位的反应差异。
在开始数据收集前，通过超声心动图和几何图确定侧卧位时的静脉压轴。对120例心脏手术后患者按随机顺序在三种体位下进行研究。在每个体位下，同时测量双臂血压，并记录中心静脉压和心率。
收缩压、舒张压、中心静脉压和心率对体位的反应存在统计学显著差异。某些体位在总体组和特定亚组中均使选定变量产生更大变化。冠状动脉旁路移植术组与瓣膜（心肌闭合或切开）亚组之间，以及有肺部疾病和无肺部疾病亚组之间均未发现差异。
心脏手术后患者的侧卧位似乎对间接/无创血压或心率测量无不利影响。然而，中心静脉压可能会出现显著差异，建议采用仰卧位来测定中心静脉压。
