A comparison of systolic and diastolic time variation with pulse pressure variation as a predictor of fluid responsiveness during pediatric liver transplantation

BACKGROUND: In pediatric patients, dynamic preload indices to predict fluid responsiveness remain controversial. Because each beat of blood pressure (BP) - waveform - contains evidence of a systolic and diastolic time interval (STI, DTI), we compared pulse pressure variation (PPV) with respiratory STI and DTI variation (STV, DTV) as predictors of fluid responsiveness during pediatric liver transplantation. METHODS: A total of 61 datasets from 16 pediatric liver transplant patients (age range one month to seven years), before and after an inferior vena cava clamp was applied, were retrospectively evaluated from electronically archived BP and central venous pressure (CVP) waveforms. STI and DTI were separated by a beat-to-beat blood pressure waveform. STV, DTV and PPV were calculated by averaging three consecutive respiratory cycles. Averaged CVP was used as a static preload index. A PPV threshold of > or =16%, a known cutoff value in pediatric surgery, was used to discriminate fluid responsiveness in the receiver operating characteristic (ROC) curve analysis. RESULTS: PPV showed correlations with STV and DTV (r = 0.65 and 0.57, P < 0.001, respectively), but not with CVP (r = -0.30, P = 0.079). The area under the ROC curves (AUC) of STV, DTV and CVP were 0.834, 0.872, and 0.613, respectively. Cut-off values of STV and DTV were 7.7% (sensitivity/specificity, 0.80/0.83) and 7.7% (sensitivity/specificity, 0.70/0.88), respectively. CONCLUSIONS: This study demonstrates that STV and DTV from a BP waveform showed the potential to predict fluid responsiveness as a surrogate of PPV during pediatric surgery.

Effects of Patent Ductus Arteriosus on Right Ventricle in Premature Infants: by M-mode and Doppler Echocardiography

PURPOSE: Patent ductus arteriosus, derived left to right shunt flows, elevate the pulmonary artery pressure in infants and children and may alter right ventricular afterload thereby right ventricular function. Therefore, we examined the effects of patent ductus arteriosus on the right ventricular systolic time interval in premature infants by non-invasive Doppler echocardiography. METHODS: Tweleve premature infants with patent ductus arteriosus were studied by M-mode and Doppler echocardiography before and after treatment with mefenamic acid. Heart rate (HR), ratio of left atrium/aorta (LA/AO), right ventricular preejection period (RVPEP), right ventricular ejection time (RVET) and right ventricular systolic time interval (RVSTI : ratio of RVPEP/RVET), both corrected or uncorrected for heart rate were measured. RESULTS: After mefenamic acid treatment, in infants showing clinical response, right ventricular preejection period (RVPEP) and right ventricular systolic time intetrval (RVSTI), both corrected or uncorrected for heart rate, decreased significantly following ductal closure (RVPEP : 70.3msecc +/- 14.5 vs 54.3msec +/- 10.9, P<0.01, RVPEPc : 129.2msec +/- 13.5 vs 111.7msec +/- 8.4, P<0.01, RVSTI : 0.38 +/- 0.09 vs 0.28 +/- 0.05, P<0.05, RVSTIc : 0.31 +/- 0.04 vs 0.27 +/- 0.03, P<0.01). CONCLUSION: Premature infants with patent ductus arteriosus exhibit echocardiographic evidence of increased RVSTI as a result of increased right ventricular afterload. This results suggest that we have to make every effort to prevent the ductal reopening or early closure of ductus arteriosus in premature infants.

Changes of Systolic Time Interval after Neonatal Asphyxia and Its Relationship with Clinical Manifestation and Prognosis / 实用儿科临床杂志

Objective To observe the changes of systolic time interval after neonatal asphyxia and explore its relationship with clinical manifestation and prognosis. Methods Tow-dimensional and Doppler echocardiography were employed to detect tow - dimension parameters and left and right ventricular STI in 27 mild and 18 severe asphyxiated neonates as well as 14 normal controls and its relationship with clinical manifestation and prognosis was analyzed. Results There was no difference in cavity and thickness of heart and great arteries between normal and asphyxiated neonates. In acute stage mild and severe asphyxiated neonates had a shorter right ventricular ejection time (RVET) than normal neonates and a longer right ventricular prejection period (RPEP) was found in severe neonates than that in normal and mild asphyxiated neonates. Left ventricular preejection time (LPEP) was prolonged in comparison with normal neonates in acute stage and convalescence. There were more cases with increased RPEP/RVET in severe asphyxiaed group than those in mild and normal group in acute stage. The incidence of heart failure in acute stage and disability in late period was higher in cases with increased RPEP/RVET than that with normal RPEP/RVET. Conclusion Asphyxia has more severe damage to right ventricle than that to left ventricle. Cases with increased RPEP/RVET are prone to suffering from heart failure in acute stage and more likely to undergo disability in late period.

EFFECTS OF ANISODAMINE ON HEMOD-YNAMICS & CARDIAC PUMP FUNCTION IN ANESTHETIZED DOGS / 中国药理学通报

Experiments were carried out in 14 closed-chest dogs anesthetized with urethane and chloralose. The tracings of FAP, the 1 st derivatives of cardiac impedance variations ( dZ/dt) , PCG and ECG were recorded synchronously on a SJ-42 Polygraph. CO and STI were determined according to Kubicek and Weissler, respectively.5-10 min after injection of 5 mg/kg wt of anisodamine intravenously, MAP and TPR reduced drastically, accompanied by a slight slowing in HR and a moderate decrease in CO; increased PEP/LVET associated with lengthening of Q-Z interval and reduction of Heather's index. There were significant differences (P

Systolic Time Interval in Cardiac Pacing: Comparison of Atrioventricular, Ventriculoatrial and Ventricular Pacing

Permanent electrostimulation is the therapy of choice for syncope due to bradycardic rhythm disturbance. In maintaining optimal hemodynamic function, the role of atrial systole has been well recorgnized and the time relationship between atrial and ventricular systole have great relation with cardiac output. Assessment of optimal mode of cardiac pacing by nonivasive method is very important for the best hemodynamic effect. To evaluate the usefulness of systolic time interval for optimal pacing mode, we calculated systolic time interval by using ventricular pacing spike on electrocardiogram to aortic opening time/left ventricular ejection time by aortic pressure curve (invasive PEP/LVET) in various modes of cardiac pacing and measured cardiac output by thermodilution method simultaneously in 9 mongrel dogs. Basal pacing cycle length were 300 msec, and the atrioventricular (AV) and ventriculoatrial (VA) interval during AB & VA sequential pacing were set at 30 msec, 60 msec and 90 msec. The result were as follows: 1) The cardiac output at AV interval of 90 msec (1.65+/-0.23 L/min) is significantly higher than 30 msec (1.38+/-0.19 L/min) in AV sequential pacing. 2) The cardiac output in ventricular pacing is higher than VA sequential pacing, but no significant changes noted among VA interval 90 msec, 60 msec and 30 msec. 3) The invasive PEP/LVET at VA interval of 90 msec (0.85+/-0.17) is significantly lower than 60 msec (0.97+/-0.16) and 30 msec (1.01+/-0.16) in AV sequential pacing. 4) The invasive PEP/LVET among VA sequential pacing with 90 msec, 60 msec, 30 msec interval and ventricular pacing did not show any significant difference. 5) When AV interval changes from 90 msec to 30 msec during AV sequential pacing, cardiac output decreased and invasive PEP/LVET increased. 6) In VA sequential pacing, there were no changes of cardiac output and invasive PEP/LVET when VA interval changes from 90 msec to 30 msec. In conclusion, systolic time interval can be used for estimation of hemodynamic changes during AV sequential pacing considering our results and other authors' results of high correlation between invasive & noninvasive PEP/LVET.

EFFECTS OF STATIC EXERCISE AND DYNAMIC EXERCISE ON SYSTOLIC TIME INTERVALS (STI) IN CHILDREN / 中国运动医学杂志

The purpose of this study was to investigate STI changes resulting from static and dynamic exercises in boys, 9-10 years old, so as to reveal the effects of physical work of different types and loads on the heart function.Our research showed that the effects of static load and dynamic load on STI in children were different. After dynamic exercise all items of STI changed significantly and PEP/LVET decreased significantly. No PEP change was found after static exercises (50% and 80% max load). Static exercise of 50% max load resulted in no IVCT change, but static exercise of 80% max load resulted in very significant change of IVCT, and the longest recovery period was found afterwards. Thus, 80% static exercise would result in a heavy, transient heart load in children.Our research also showed that the changes of HR?systolic blood pressure?LVET after dynamic load and static load were significantly different indicating that oxygen consumption in heart muscles was higher during dynamic exercise and the effect of dynamic exercise on heart was stronger.

A STUDY OF SYSTOLIC TIME INTERVALS OF ATHLETES / 中国运动医学杂志

The purpose of this study is to investagate the meaning of systolic time intervals (STI) in evaluating cardiac functional condition of athletes.1. STI and step test were examined on 13 sprinters, 8 jumpers, 5 throwers and 5 distance runners during early, middle and the last phases in summer training season.No significant changes of the left ventricular ejection time (LVET), the pre-ejection period (PEP) and PEP/LVET ratio were found from examinations on athletes in the three different phases.The cases were divided into two groups of PEP/LVET ratio increased more than 0.05 (N=8) and PEP/LVET ratio decreased more than 0.05 (N=10) by the different of PEP/LVET ratio between linked phases examinations. Athough two of PEP/LVET ratio of each group were different evidently (P