Right ventricular function in COPD patients during weaning from mechanical ventilation

We studied the right ventricular function during a successful weaning period in 7 COPD patients without LV disease who had been mechanically ventilated for several days after an acute exacerbation of their disease. A Swan-Ganz ejection fraction thermodilution catheter performed measurements of right ventricular ejection fraction (RVEF) and right ventricular end-diastolic volume index (RVEDVI) before and fifteen minutes after disconnection from the ventilator at the maintenance FiO₂. Although pulmonary artery pressure (PAP) rose from 25±4 to 28.5±4.5 mmHg after disconnection from the ventilator, RVEF (0.36±0.56 to 0.35±0.12) and RVEDVI (117±51 to 126±52 ml/m²) remained similar in both conditions. We concluded that right ventricular systolic function assessed with modified pulmonary artery catheter was maintained during the weaning phase in such weanable patients. This method could easily detect any fall of RVEF or diastolic RV enlargement able to impair the weaning in some patients.     

Right ventricular ejection fraction measurement in moderate acute respiratory failure (ARF). Effects of PEEP

Eight patients mechanically ventilated for acute respiratory failure were submitted to increasing levels of PEEP, from 0 to 15 cm H₂O. Right ventricular ejection fraction (RVEF) and end-diastolic volume index (RVEDVI) were measured using the fast response thermistor Swan-Ganz catheter. PEEP induced a linear decrease of cardiac index, while the pulmonary artery pressure increased. In three patients (group A) with a RVEDVI larger than 120 ml at ZEEP, RVEF decreased and RVEDVI increased with PEEP. In the other five patients (RVEDVI>120 ml, group B), RVEF was unchanged and RVEDVI decreased at PEEP 15 cm H₂O. This study suggest that RV changes induced by PEEP are probably a function of the initial RVEF and RVEDVI.     

Influence of constant sustained positive airway pressure on right ventricular performance

Objective The detrimental effect of positive airway pressure on right ventricular (RV) performance is controversial and the aim of this study was to determine the effects of constant positive airway pressure without ventilatory fluctuation on RV performance with the aid of a pulmonary arterial catheter equipped with a rapid response thermistor for measuring RV ejection fraction (RVEF) and RV end-diastolic volume index (RVEDVI).Design A prospective, clinical study.Setting The central operating theatre of a university hospital.Patients Nine patients who had major surgery and required right heart catheterization for normal clinical management.Measurements and results Cold indicator was injected into the RV 4 or 5 times for each airway pressure (0, 10 or 20 cmH₂O) which was maintained manually stable for 15 s, and 9 paired data were analyzed by repeated-measures analysis of variance. They are separated into two groups; RVEF at zero airway pressure greater (A group) or less (B group) than 0.4. In A group (7 patients), increasing airway pressures (0 vs 10 vs 20 cmH₂O) did not affect RVEF (0.55±0.05 vs 0.54±0.06 vs 0.56±0.04), RVEDVI (69±36 vs 73±29 vs 58±20 ml·m^–2), or stroke volume index (SVI: 38±18 vs 40±17 vs 33±13 ml·beat^–1 ·m^–2); however, in B (2 patients), RVEF (0.35 and 0.38 vs 0.31 and 0.28 vs 0.19 and 0.17) and SVI (35 and 28 vs 32 and 27 vs 27 and 23) decreased, while RVEDVI increased (99 and 73 vs 103 and 97 vs 146 and 132).Conclusions In most patients, the changes in RVEF, SVI, and RVEDVI did not occur under constant positive airway pressure, therefore the changes reported in mechanically ventilated patients may not attributable to the extent of positive airway pressure but rather to abrupt increases in airway pressure. There appears, however, to be patients whose RV function is so disturbed that they cannot cope with increased afterloads.     

Left ventricular function during weaning of patients with chronic obstructive pulmonary disease

Objective Determine the evolution of left ventricular ejection fraction during weaning.Design Prospective study.Setting Intensive care unit of a university teaching hospital.Patients and participants 12 consecutive mechanically ventilated patients, without documented coronary artery disease, suffering from acute exacerbation of chronic obstructive pulmonary disease and able to be weaned.Measurements and results Left ventricular ejection fraction was determined during mechanical ventilation, inspiratory pressure support (10 cmH₂O) and spontaneous ventilation with constant inspiratory oxygen fraction using technetium^99m radionuclide angiography. Spontaneous ventilation induced a significant decrease in left ventricular ejection fraction from 54.5±12.4 to 47.0±13% (p<0.01). Inspiratory pressure support induced a slight but non-significant decrease in left ventricular ejection fraction from 55.0±12.1 to 50.3±12.4%. Left ventricular ejection fraction was homogeneously reduced by spontaneous ventilation without patent regional wall motion abnormalities of the left ventricle. Myocardial²⁰¹thallium imaging performed 15 min after weaning showed a normal perfusion in the left ventricle anterior and posterior free wall.Conclusion Weaning of patients suffering from chronic obstructive pulmonary disease without coronary artery disease induced a significant reduction in left ventricular ejection fraction. The non significant decrease in left ventricular ejection fraction observed with inspiratory pressure support suggested that our results might be explained by a weaning induced increase in afterload.     

Monitoring of right ventricular function using a conventional slow response thermistor catheter

Objective To investigate whether determination of right ventricular end-diastolic volume (RVEDV) and right ventricular ejection fraction (RVEF) can be performed with reasonable accuracy and reproducibility using a conventional slow response thermistor pulmonary artery catheter (CPAC) applying an adaptive algorithm.Design To study RVEDV and RVEF simultaneously with pulmonary artery catheters equipped with slow and fast response thermistors (FRPAC) under a broad range of cardiac output.Setting Laboratory of Institute of Experimental Surgery, Technical University.Animals 11 anaesthetised piglets.Interventions Hypovolemia (V–) was induced by withdrawal of blood up to 50 ml/kg, hypervolemia (V+) was produced by retransfusing blood and adding up to 30 ml/kg hydroxyethyl starch. In 5 animals in phases V–and V+ beta-adrenergic stimulation was achieved with dobutamine. Finally pulmonary artery hypertension was induced by infusion of small air bubbles.Measurements and results Cardiac output (CO), RVEDV and RVEF were determined simultaneously with FRPAC and CPAC placed in the same pulmonary artery branch. Measurements were repeated 8 times sequentially in steady state normovolemia. A total of 130 measurements could be analysed. The coefficient of variation was 6.7±4.2 for CO_(FRPAC) and 4.6±1.7% for CO_(CPAC); for RVEF it was 9.7±6.2% (FRPAC) and 9.9±3.9% (CPAC); for RVEDV it was 11.6±4.8% (FRPAC) and 8.54±3.2 (CPAC). Mean difference (bias) was 0.06±0.39 l/min for CO measured with both methods, 19±35 ml for RVEDV and –3.3±6.5% for RVEF. CO_(CPAC) displayed a strong correlation to CO_(FRPAC) (R=0.97,p=0.001) as well as RVEF (R for RVEF_(CPAC) versus RVEF_(FRPAC)=0.90,p=0.001). R for RVEDV_(CPAC) versus RVEDV_(FRPAC) was 0.67,p=0.001. We conclude that this animal study demonstrates good agreement between RVEF and RVEDV obtained with catheters equipped with a fast response thermistor or with a conventional slow response thermistor allowing accurate monitoring of right ventricular function with a conventional pulmonary artery catheter.Supported in part by grants from BMFT (grant number 0706908)     

感染性休克患者右心室功能不全的研究

目的：观察感染性休克患者右心室功能的变化,为防治感染性休克患者的右心室功能不全进一步提供理论依据。方法：选择急救中心1997年10月至2000年10月3月年收治的感染性休克患者36例,运用REF－1^TM右心功能监测仪和HP监护仪,结合超声心动图观察右心室射血分类（RVEF）、右心室室壁应力（RVWS）、充盈早期最大流速（E）与晚期最大流速（A）之比（E／A）充盈早期最大流速减速时间（Dte)、平均肺动脉压（mPA)、肺血管阻力指数（PVRI）、中心静脉压（CVP）、右心室舒张末容积指数（）RVEDVI）、心排指数（CI）、肺动脉嵌压（PAWP）。右心室每搏作功指数（RVSWI）和右心室作功指数（RCWI）的变化。结果：休克早期患者即出现轻度右心室功能不全,表现为RCWI、RVSWI、RVEF、E／A、Dte的下降及RVWS的增加;随着休克病情的恶化,RCWI、RVSWI、RVEF、E／AD Dte的进一步下降及RVWS的进一步增加;而休克纠正后,RVEF和RVWS基本恢复正常,RCWI、RVSWI、E／A、Dte及RVWS均未见明显改善。结论：“感染性休克患者早期右心室功能减退,晚期出现右心衰竭;随着休克的纠正,右心室功能一定程度的改善,但未完全恢复正常。     

Right and left ventricular performance in acute hypoxemic respiratory failure

We examined biventricular performance on two occasions in 28 patients with acute hypoxemic respiratory failure (ARF), using a combination of invasively determined pressures and flows as well as radionuclide scintigraphy to measure the right and left ventricular ejection fractions (RVEF and LVEF, respectively). From the EF and concurrently measured thermodilution stroke volumes, we calculated right and left ventricular end-diastolic and end-systolic volume indices (EDVI and ESVI, respectively). Regression analysis demonstrated that changes (delta) in global right ventricular function (RVEF) were inversely correlated with concurrent changes in the mean pulmonary arterial pressure (MPAP): delta RVEF = 0.015-0.015 delta MPAP (r2 = 0.60; p less than .005), while an increase in right ventricular preload (RVEDVI) was positively correlated with changes in MPAP: delta RVEDVI = 2.68 +/- 6.27 delta MPAP (r2 = 0.46; p less than .005). Global left ventricular function (LVEF) was related to changes in systemic pressures as well as to right-sided events: delta LVEF = -0.01-0.0015(delta RVESVI) + 0.001(delta BP systolic)-0.42(CVP/RVEDVI) (r2 = 0.35; p less than .01). These data confirm the significant influence of right ventricular afterload on RVEF in ARF patients and an apparent interrelationship between altered right ventricular systolic function and global left ventricular performance.     

Right ventricular myocardial function in ARF patients

Objective To examine the hemodynamic effects of external positive end-expiratory pressure (PEEP) on right ventricular (RV) function in acute respiratory failure (ARF) patients.Design Prospective, with retrospective analysis on the basis of RV volume response to PEEP.Setting General intensive care unit in a university teaching hospital.Patients 20 mechanically ventilated ARF patients (mean lung injury score=2.6±0.45 SD).Intervention Incremental levels of PEEP (0–5–10–15 cmH₂O) were applied and RV hemodynamics were studied by means of a Swan-Ganz catheter with a fast-response thermistor for right ventricular ejection fraction (RVEF) measurement. According to their response to PEEP 15, two groups of patients were defined: group A (9 patients) with unchanged or increased RV end-diastolic volume index (RVED-VI) and group B (11 patients) with decreased RVEDVI.Measurements and results At zero PEEP (ZEEP) the hemodynamic parameters of the two groups did not differ. In group A, cardiac index (CI) and stroke volume index (SI) decreased at all PEEP levels (5, 10, and 15 cmH₂O), while RVEF started to decrease only at a PEEP of 10 cmH₂O (–10.8%), and RVES(systolic)VI increased only at PEEP 15 cmH₂O (+21.5%). RVED-VI was not affected by PEEP. In group B, CI and SI decreased at all PEEP levels (5, 10, and 15 cmH₂O). Similarly, RVEDVI started to decrease at PEEP 5 cmH₂O, while RVESVI decreased only at PEEP 15 cmH₂O (–21.4%). RVEF was not affected by PEEP in this group. In each patient the slope of the relationship between RVEDVI and right ventricular stroke work index (RVSWI), expressing RV myocardial performance, was studied. This relationship was significant (no change in RV contractility) in 8 of 11 patients in group B and in only 2 patients in group A. In 4 patients in group A, PEEP shifted the RVSWI/RVEDVI ratio rightward in the plot, indicating a decrease in RV myocardial performance in these patients.Conclusions PEEP affects RV function in ARF patients. The decrease in cardiac output is more often associated with a preload decrease and no change in RV contractility. On the other hand, the finding of increased RV volumes with PEEP may be associated with a reduction in RV myocardial performance. Thus, these results suggest that assessment of RV function by PEEP and preload recruitable stroke work may disclose otherwise unpredictable alterations in RV function.Partially supported by Consiglio Nazionale delle Ricerche grant, Italy     

连续右心容量监测指导感染性休克的液体复苏

目的 比较以右房压(right atria pressure,RAP)和右室舒张末期容积指数(risht ventricular end-diastolic volume index,RVEDVI)指导老年感染性休克患者液体复苏的效果.方法前瞻性、随机、对照临床研究.入选2007年1月至2008年10月入住浙江医院重症加强治疗病房,低血压发生时间<6 h的老年感染性休克患者30例,应用改良的容量性肺动脉导管连续同步监测容量和压力的变化,指导液体复苏.随机分为对照组和实验组,对照组的治疗目标为RAP 8～12 mmHg,实验组的治疗目标为右室射血分数(right ventricular ejection fraction,RVEF)校正的RVEDVI达到100～200 mL/m~2.记录液体复苏治疗前后两组患者RAP、肺动脉嵌顿压(pulmonary artery occlusion pressure,PAOP)、RVEF、RVEDVI等参数;记录治疗前后两组患者急性牛理和慢性健康评分(acute physiology and chronic health e-valuation Ⅱ,APACHE Ⅱ)和混合静脉血氧饱和度(mixed venous oxygen saturation,SvO_2)的变化;记录治疗前两组患者动脉血乳酸浓度及治疗后6 h乳酸清除率;并将液体复苏治疗后6 h RVEDVI差值与乳酸清除率作相关分析.结果 对照组液体复苏15例达标12例,达标率为80%,实验组液体复苏15例达标13例,达标率为86.7%,两组差异无统计学意义(P>0.05).液体复苏达标患者中,实验组与对照组相比,RVEDVI、RVEDVl差值、RVEF(%)、RAP和6 h乳酸清除率(%)明显增高[(119.92±15.65)mL/m~2,(38.54±6.63)mL/m~2,(36.08±3.40),(14.46±1.13)mmHg,(58.31±13.36)vs.(99.92±11.71)mL/m~2,(21.00±11.01)mL/m~2,(32.42±2.47),(13.08±1.08)mmHg,(43.99±16.26);P<0.05],但PAOP、APACHE Ⅱ和SvO~2差异无统计学意义(P>0.05).液体复苏治疗6 h后两组患者RVEDVI差值与乳酸清除率显著相关(P<0.01).结论以RVEDVI指导老年感染性休克患者液体复苏与传统的以RAP为指导的液体复苏相比,复苏过程更安全,对乳酸清除率的改善更为满意,可能更好地改善全身组织灌注与氧合.     

Effects on right ventricular function of a change from dopamine to dobutamine in critically ill patients

In 15 critically ill patients requiring adrenergic support, right ventricular ejection fraction (RVEF) and right ventricular (RV) volumes were measured by the thermodilution technique receiving 5 micrograms/kg.min of dopamine and after replacement by the same dose of dobutamine. Shift from dopamine to dobutamine resulted in significant increases in stroke index from 28.1 +/- 3.6 to 31.0 +/- 3.8 ml/m2 (p less than .01) and significant decreases in pulmonary artery balloon-occluded pressure from 15.1 +/- 1.0 to 13.9 +/- 1.2 mm Hg (p less than .05) and right atrial pressure (RAP) from 14.0 +/- 1.3 to 12.2 +/- 1.1 mm Hg (p less than .05). RVEF increased slightly but significantly from 21.5 +/- 2.7% to 23.7 +/- 2.9% (p less than .01) so that RV end-diastolic volume (RVEDVI) was unchanged (140 +/- 12 vs. 141 +/- 12 ml, nonsignificant). RVEDVI/RAP ratio increased from 11.3 +/- 1.0 to 12.9 +/- 1.1 ml/mm Hg (p = .037). These results support the view that dobutamine has more favorable effects on RV function than dopamine in critically ill patients in the absence of profound hypotension and also indicates that higher filling pressures under dopamine administration can be related to changes in ventricular pressure/volume relationship.     

Thermodilution determination of right ventricular volume and ejection fraction: a comparison with biplane angiography

In 13 patients without tricuspid incompetence, we compared the values of right ventricular ejection fraction (RVEF) and right ventricular end-diastolic volume (RVEDV) obtained with biplane angiography and thermodilution at end-inspiration. A modification of Simpson's rule was used to measure angiographic volumes, and a new pulmonary artery catheter equipped with a rapid response thermistor was used to measure the ejection fraction by the Holt plateau method. The correlation between the two methods was acceptable (r = 0.83 for RVEF, r = 0.71 for RVEDV) despite the limitations of both angiography and thermodilution. Thermodilution underestimated RVEF and overestimated RVEDV when compared to angiography. The variation coefficient with thermodilution for five measurements of the RVEF per patient was 12 +/- 5%. In addition to pressure and cardiac output measurements, monitoring of RVEF and RVEDV in the ICU should be possible with such a catheter. Further work is needed to assess the clinical relevance of these added data and their use for optimizing the therapy of right ventricular failure in acutely ill patients.     

Effects of inhaled nitric oxide on right ventricular function in severe acute respiratory distress syndrome

Objective To compare the effects of inhaled nitric oxide (NO) and an infusion of prostacyclin (PGI₂) on right ventricular function in patients with severe acute respiratory distress syndrome (ARDS).Design Randomized prospective short-term study.Setting: Post-surgical ICU in an university hospital.Patients 10 patients with severe ARDS referred to our hospital for intensive care.Interventions In random sequence the patients inhaled NO at a concentration of 18 parts per million (ppm) followed by 36 ppm, and received an intravenous infusion of PGI₂ (4 ng·kg^–1·min^–1).Measurement and results Inhalation of 18 ppm NO reduced the means (±SE) pulmonary artery pressure (PAP) from 33±2 to 28±1 mmHg (p=0.008), increased right ventricular ejection fraction (RVEF), as assessed by thermodilution technique, from 28±2 to 32±2% (p=0.005), decreased right ventricular end-diastolic volume index from 114±6 to 103±8 ml·m^–2 (p=0.005) and right ventricular end-systolic volume index from 82±4 to 70±5 ml·m^–2 (p=0.009). Mean arterial pressure (MAP) and cardiac index (CI) did not change significantly. The effects of 36 ppm NO were not different from the effects of 18 ppm NO. Infusion of PGI₂ reduced PAP from 34±2 to 30±2 mmHg (p=0.02), increased RVEF from 29±2 to 32±2% (p=0.02). Right ventricular end-diastolic and end-systolic volume indices did not change significantly. MAP decreased from 80±4 to 70±5 mmHg (p=0.03), and CI increased from 4.0±0.5 to 4.5±0.5 l·min^–1·m^–2 (p=0.02).Conclusions Using a new approach to selective pulmonary vasodilation by inhalation of NO, we demonstrate in this groups of ARDS patients that an increase in RVEF is not necessarily associated with a rise in CI. The increase in CI during PGI₂ infusion is probably related to the systemic effect of this substance.Supported by DFG Fa 139/1-2/2-2     

Inhaled nitric oxide does not improve cardiac or pulmonary function in patients with an exacerbation of chronic obstructive pulmonary disease.

OBJECTIVE: To determine whether inhaled nitric oxide (NO) improves right ventricular function in mechanically ventilated patients with severe chronic obstructive pulmonary disease (COPD). DESIGN: Open, prospective, controlled trial. SETTING: General intensive care unit of a community hospital. PATIENTS: Twelve patients with acute respiratory failure caused by acute exacerbation of COPD requiring mechanical ventilation. INTERVENTIONS: Insertion of a pulmonary artery catheter modified with a rapid response thermistor and a radial arterial catheter. Nitric oxide was then administered to the patient via a T piece placed between the Y piece of the ventilator and the endotracheal tube. MEASUREMENTS AND MAIN RESULTS: Hemodynamic and gasometric variables were recorded before NO inhalation, during administration of inhaled NO (20 ppm, 20 mins), and 20 mins after NO discontinuation. Inhaled NO reduced pulmonary artery pressure from 26 +/- 6 to 22 +/- 5 mm Hg (p = .0004), but arterial oxygenation, cardiac output, and right ventricular ejection fraction remained unmodified (41% +/- 9% vs. 41% +/- 8%; not significant). Calculated pulmonary vascular resistance decreased from 453 +/- 233 to 348 +/- 108 dyne x sec/cm5 x m2 (p = .02), and right ventricular volumes did not change. Subsequently, right ventricular end-systolic pressure/volume ratio decreased from 0.52 +/- 0.22 to 0.44 +/- 0.19 mm Hg/mL/m2 (p = .01). No significant correlation was observed between the changes of pulmonary artery pressure (or pulmonary vascular resistance) and changes of right ventricular ejection fraction. CONCLUSION: Inhalation of NO does not seem to improve either right ventricular function or arterial oxygenation in patients with acute respiratory failure caused by acute exacerbation of COPD.     

Evolution of right ventricular performance after CABG

34 patients scheduled for coronary artery bypass graft (CABG) surgery were studied during postoperative period. Right ventricular performance was specially performed with use of cardiac output computer REF-1 Edwards Lab., before Anaesthesia (T1) and at 6 investigation times after surgery during and after mechanical ventilation. The sixth first postoperative hours were marked by a decrease of cardiac index (2.56±0.4 to 2.41±0.4 l·mn^-1·m²) and right Ventricular Ejection Fraction (RVEF) (0.48±0.07 to 0.37±0.09). The second period was the weaning period with a further drop of RVEF (0.43±0.1 to 0.36±0.07) without change in cardiac index (2.80±0.5 l·mn^-1·m², suggesting a ventricular postoperative and weaning depression, as previously described for the left ventricle. In addition, postoperative tachycardia (Heart rate=59±9 at T1 to 95±14 at T7) may contribute to myocardial ischemia.     

Right ventricular systolic time intervals determined by means of a pulmonary artery catheter.

OBJECTIVES: To evaluate the right ventricular systolic time interval as an index of right ventricular function and also to ascertain whether the right ventricular ejection fraction may be determined by means of a conventional pulmonary artery catheter. DESIGN: Prospective study. SETTING: Intensive care unit. PATIENTS: Eight, consecutive critically ill adult patients. METHODS: Simultaneous blind measurements, performed by two investigators, of the right ventricular systolic time interval and right ventricular ejection fraction, determined by means of a pulmonary artery catheter. Two studies, separated by an interval of 24 hrs, per patient. Linear regression analysis. Multiple regression test. RESULTS: Of the 16 studies performed, two determinations of right ventricular systolic time intervals were technically inadequate. In the remaining 14 valid studies, we found one close linear correlation between the right ventricular ejection fraction and the preejection period/ejection time quotient measured using the simultaneous display of the electrocardiogram (EKG) and pulmonary arterial pressure curve (r2 = .90, p < .001, right ventricular ejection fraction = 68.96-60.59 x [right ventricular preejection period/right ventricular ejection time]). The method proved to be simple, very accurate, with little interobserver variation (8.09 +/- 10.6% interobserver variation for right ventricular preejection period/right ventricular ejection time) and provided adequate information regarding situations in which the performance of the right ventricle is modified in a given patient. The right ventricular preejection period/right ventricular ejection time quotient was the only variable that displayed a significant relationship with the right ventricular ejection fraction in the multivariate analysis (p < .001). CONCLUSIONS: Right ventricular systolic time intervals, measured using the simultaneous display of the pulmonary artery catheter curve and EKG, provide adequate information regarding right ventricle performance in critically ill patients. The close linear correlation between the right ventricular preejection period/right ventricular ejection time quotient and the right ventricular ejection fraction enables the investigator to estimate, with a high degree of accuracy, the right ventricular ejection fraction and the values derived from the preload of the right ventricle, without the need for a modified pulmonary artery catheter.     

Effects of norepinephrine on right ventricular function in septic shock patients

Objective To study the effects of norepinephrine on right ventricular function in patients with hyperdynamic septic shock.Design Prospective, open study.Setting A 15 bed ICU in a university hospital.Patients 9 patients with hyperdynamic septic shock (SBP<90 mmHg, Cl4l·min^–1·m^–2, SVRI850 dynes·s·cm^–5m^–2 and oliguria).Interventions Plasma volume expansion was used to correct a suspected volume deficit and then, norepinephrine infusion was started and titrated to restore systemic blood pressure to the normal range (mean infusion rate: 1.1±0.2 mcg·kg^–1·min^–1). Norepinephrine was the only vasoactive agent used in these patients.Measurements and results A modified Swan-Ganz catheter mounted with a fast response thermistor was inserted in each patient, allowing repeated measurements of RVEDVI and RVEF. At time of inclusion to the study, all but one patient had elevated MPAP (23±4 mmHg) and RVEF50%, and all patients had RVEDVI90 ml·m^–2. During norepinephrine infusion, MAP increased from 51±9 to 89±10 mmHg (p<0.0001), PVRI increased from 204±35 to 286±63 dynes·s·cm^–5·m^–2 (p<0.05), and despite this increase in right ventricular afterload, no detrimental effect in RVEF (36±11 to 36±10%) or in RVEDVI (116±30 to 127±40 ml·m^–2) was observed. A Frank-Starling relationship for the right ventricle was constructed by plotting an index of ventricular performance (RVSWI) against an index of ventricular preload (RVEDVI). A significant upward shift to the right of the relationship was observed during norepinephrine infusion.Conclusion It was concluded that norepinephrine exerted a favourable effect on right ventricular function.Work done at Sainte Marguerite Hospital, Marseille, France     

Simultaneous assessment of right ventricular ejection fraction and central haemodynamics at rest and during exercise in patients with pulmonary hypertension

Summary. In 10 patients, aged 55–73, with pulmonary hypertension, right ventricular ejection fraction (RVEF) was measured simultaneously with central haemodynamics twice, at rest and during exercise. In the first investigation, RVEF was measured with first pass (FQ) radionuclide angiocardiography using ¹³³Xe and ⁹⁹Tc^m as tracers. In the second investigation after 1 h's rest, RVEF was measured with equilibrium (EQ) radionuclide angiocardiography. Significant correlations were found between RVEF and pulmonary artery pressure (r = - 0. 76 to - 0. 88) and between RVEF and right arterial pressure (r= -0. 76 to -0. 84) at rest and during exercise. RVEF was low or decreased during exercise in all patients with haemodynamic signs of right ventricular failure. Good correlations were found between the FP and EQ techniques for measuring RVEF both at rest, r= 0.86, and during exercise, r= 0.91. RVEF, measured with the FP technique, showed better reproducibility and better correlation to haemodynamic variables and to history of right ventricular failure than the EQ technique. Thus, the FP technique seemed to be the method of choice for assessment of RVEF.     

Thermodilution measurement of right ventricular ejection fraction with a modified pulmonary artery catheter

In 14 critically ill patients in stable cardiopulmonary status, right ventricular ejection fraction (RVEF) was measured by thermodilution technique and by radionuclear (gated first pass) technique. The pulmonary artery catheter was equipped with a fastresponse thermistor and an intracardiac ECG monitor. In addition, the proximal lumen ended in a 3-hole port 21 cm from the tip of the catheter to facilitate mixing of the cold bolus above the tricuspid valve. The use of a new algorithm based on an exponential curve analysis of the thermodilution curve limited the variability of RVEF determinations to 7.6%. The correlation between RVEF measured by thermodilution and radionuclear techniques was significant (y= 12.7+0.49x, r=0.67, p<0.01). However, the values obtained by thermodilution were usually lower, especially for high RVEF. Nevertheless, although some discrepancy was found, thermodilution techniques allow simple, accurate and repetitive bedside measurements of right ventricular volumes in the critically ill.     

Evaluation of right ventricular function by assessment of cardiac efficiency: Influence of induction of anaesthesia in coronary artery bypass grafting patients

Considering the heart as a physical pump cardiac efficiency is calculated from the ratio of cardiac work performed to the maximum level of energy of the heart. The aim of the study was to compare cardiac efficiency with cardiac output and right ventricular ejection fraction. Nine patients scheduled for coronary artery bypass grafting were investigated. A femoral arterial and a right ventricular ejection fraction pulmonary artery catheter were placed in the awake state. Anaesthesia was induced with eltanolone and fentanyl. Cardiac output, pulmonary artery and central venous pressures, and right ventricular ejection fraction were measured in the awake state (baseline), 2 min after induction of anaesthesia and 1 and 5 min after intubation. Cardiac effeciency was calculated by dividing the stroke work by the maximum energy of the heart as calculated from the pressure volume diagram. An analysis of variance was carried out for cardiac efficiency, cardiac output and right ventricular ejection fraction. Cardiac efficiency was significantly (p<0.05) reduced 1 min after intubation from 28±11 to 14±5%. In contrast the right ventricular ejection fraction (from 48±10 to 35±13%) and cardiac output (from 6.5±1.5 to 5.3±1.2L/min) did not change significantly during the induction of anaesthesia. Cardiac efficiency was found to be a more sensitive parameter to describe changes in the right ventricular function than the ejection fraction and cardiac output during induction of anaesthesia with eltanolone and fentanyl which was used as a model to vary cardiac performance and afterload.