心脏外科术后病人下腔静脉管径与中心静脉压相关性的研究

目的 探讨心脏外科术后患者的下腔静脉内径及塌陷率与中心静脉压的相关性。方法 选取我院心血管外科重症监护病房的瓣膜置换术后患者84例,于术后48 h内首次进行床旁超声检测,于右锁骨中线与右腋前线的中线上获取经肝的下腔静脉二维长轴超声图像,测量下腔静脉随呼吸变化时的最大横径与最小横径（IVCmax、IVCmin）,并计算其管径塌陷率,同时经颈外静脉入上腔静脉导管实时测定中心静脉压（CVP）,Spearman及Pearson法分别分析机械通气和自主呼吸状态时IVCmax、IVCmin、塌陷率与CVP的相关性。结果 入组对象的下腔静脉IVCmax为（1.54±0.45）cm,IVCmin为（1.19±0.45）cm,塌陷率为（24.02±11.52）%,CVP为（9.46±4.02）cm H2O（1 cm H2O=0.1 kPa）。IVCmax和IVCmin均与CVP呈正相关（P＜0.01）,下腔静脉塌陷率与CVP呈负相关（P＜0.01）。机械通气和自主呼吸患者的IVCmax、IVCmin及下腔静脉塌陷率与CVP均有较好的相关性（P＜0.01）。结论 应用下腔静脉管径和塌陷率可无创预测心脏外科术后患者CVP。动态测量下腔静脉管径,有利于容量反应性的判断。     

A comparison between continuous central venous pressure measurement from right atrium and abdominal vena cava or common iliac vein

Objective To determine the accuracy of meancontinuous central venous pressure (CVP) measurements in the abdominal vena cava.Design We simultaneously measured the CVP at the superior vena cava or right atrium and at the abdominal vena cava or common iliac vein. The study was conducted at the pediatric intensive care unit of a major university-affiliated medical center.Patients Nine patients, aged 6 months to 14 years, were included in our study.Measurements and results Elevencontinuous recordings of 12 to 68 min were taken, eight of them while the children were mechanically ventilated. Mean overall CVP ranged from 3 to 30 mmHg. A total of 519 simultaneous recordings were made, of which 515 (99.2%) were within the accepted limits of agreement of ±2 mmHg: 301 (58%) with CVP of ±mmHg, 189 (36,4%) with CVP of ±1 mmHg, and 25 (4.8%) with CVP of ±2 mmHg. The mean pressure difference was –0.22±1.52 mmHg. Accuracy was maintained within all ranges of CVP (3–10, 11–20, and 21–30 mmHg) and was not influenced by mechanical ventilation or abdominal fluid colection.Conclusion In children with no obstruction of blood flow from the abdominal vena cava to the right atrium, the pressure in the abdominal vena cava or common iliac vein accurately reflects the pressure in the right atrium.     

Central venous pressure and shock index predict lack of hemodynamic response to volume expansion in septic shock: A prospective,observational study

Purpose

Volume expansion is a common therapeutic intervention in septic shock, although patient response to the intervention is difficult to predict. Central venous pressure (CVP) and shock index have been used independently to guide volume expansion, although their use is questionable. We hypothesize that a combination of these measurements will be useful.

Methods

In a prospective, observational study, patients with early septic shock received 10-mL/kg volume expansion at their treating physician's discretion after brief initial resuscitation in the emergency department. Central venous pressure and shock index were measured before volume expansion interventions. Cardiac index was measured immediately before and after the volume expansion using transthoracic echocardiography. Hemodynamic response was defined as an increase in a cardiac index of 15% or greater.

Results

Thirty-four volume expansions were observed in 25 patients. A CVP of 8 mm Hg or greater and a shock index of 1 beat min^− 1 mm Hg^− 1 or less individually had a good negative predictive value (83% and 88%, respectively). Of 34 volume expansions, the combination of both a high CVP and a low shock index was extremely unlikely to elicit hemodynamic response (negative predictive value, 93%; P = .02).

Conclusions

Volume expansion in patients with early septic shock with a CVP of 8 mm Hg or greater and a shock index of 1 beat min^− 1 mm Hg^− 1 or less is unlikely to lead to an increase in cardiac index.