Total Peripheral Vascular Resistance Index Research Articles

Is it possible to augment myocardial protection during cardiopulmonary bypass by administration of inhalational anesthetics?

Aim: To evaluate the possibility to augment myocardial protection with desflurane and sevoflurane by prolongation of their delivery into the oxygenator of the cardiopulmonary bypass (CPB) pump during surgical myocardial revascularization.Materials and methods: This randomized prospective study included 75 patients with ischemic heart disease who underwent aortocoronary and mammary coronary bypass grafting with extracorporeal circulation from 2014 to 2017. The patients were allocated into the three study group by means of a random number table generated by Statistica 10.0 software, depending on the anesthetic agent used: group 1, desflurane (n=30), group 2, sevoflurane (n=28), and group 3 (control), propofol (n=17). Desflurane and sevoflurane were delivered into the oxygenator during the artificial circulation. Hemodynamic parameters were assessed, such as cardiac index, total peripheral vascular resistance index, pulmonary artery wedge pressure. Changes in lactate, pyruvate, alanine, glutamate, glutamine, aspartate, asparagine, taurine, leucine, isoleucine and valine levels over time were assessed in blood taken from the heart coronary sinus before aortal clamping, before release of the clamp and after 30 minutes of reperfusion. During the first 24 hours post perfusion, we assessed the incidence of postperfusion heart failure (PPHF), duration of mechanical ventilation and duration of stay in the intensive care unit. Troponin I levels were measured at 12 and 24 hours after the intervention.Results: There were no significant differences in the changes of the hemodynamic parameters over time in all the groups. The PPHF incidence and the course of the postoperative period were similar in all the groups. Irrespective on the type of the anesthesia, lactate and pyruvate levels increased during the CPB, with no significant differences between the groups, as well as the postoperative troponin I levels at 12 and 24 hours after surgery. No differences between the groups were found for the changes of amino acid levels over time, except a significant reduction of alanine levels during the aortal clamp in the group 3.Conclusion: Prolongation of desflurane and sevoflurane delivery into the CPB pump oxygenator does not augment myocardial protection during myocardial revascularization surgery.

Hemodynamic changes in standing-up test of children and adolescents with postural tachycardia syndrome

To explore the hemodynamic changes in standing-up test of children and adolescents with postural tachycardia syndrome (POTS) and to compare hemodynamic parameters of POTS patients with decreased cardiac index (CI) and those with not-decreased CI. A retrospective study was conducted to show the trends of CI, total peripheral vascular resistance index (TPVRI), heart rate and blood pressure in standing-up test of 26 POTS patients and 12 healthy controls, and to compare them between the two groups. The POTS patients were divided into two groups based on CI decreasing or not in standing-up test, namely decreased CI group (14 cases) and not-decreased CI group (12 cases). The trends of the above mentioned hemodynamic parameters in standing-up test were observed and compared between decreased CI group and not-decreased CI group. In standing-up test for all the POTS patients, CI (F=6.936, P=0.001) and systolic blood pressure (F=6.049, P<0.001) both decreased significantly, and heart rate increased obviously (F=113.926, P<0.001). However, TPVRI (F=2.031, P=0.138) and diastolic blood pressure (F=2.018, P=0.113) had no significant changes. For healthy controls, CI (F=3.646, P=0.016), heart rate (F=43.970, P<0.001), systolic blood pressure (F=4.043, P=0.020) and diastolic blood pressure (F=8.627, P<0.001) all increased significantly in standing-up test. TPVRI (F=1.688, P=0.190) did not change obviously. The changing trends of CI (F=6.221, P=0.001), heart rate (F=6.203, P<0.001) and systolic blood pressure (F=7.946, P<0.001) over time were significantly different between the patients and healthy controls, however, no difference was found in TPVRI and diastolic blood pressure (P > 0.05). Among the POTS patients, CI was significantly different between decreased CI group and not-decreased CI group (F=14.723, P<0.001). Systolic blood pressure of the former decreased obviously (F=8.010, P<0.001), but it did not change obviously in the latter (F=0.612, P=0.639). Furthermore, none of the changes of TPVRI, heart rate and diastolic blood pressure in standing-up test were significantly different between the two groups (P > 0.05). Age was an independent factor for decreased CI patients (P=0.013, OR=2.233; 95% CI, 1.183 to 4.216). POTS patients experience vital hemodynamic changes in standing-up test, part of them suffering from decreased CI, but others from not-decreased CI. Age is an independent factor for patients suffering from decreased CI.

Peculiarities of hemodynamic status of healthy newborns in early neonatal period

The study is devoted to the assessment of hemodynamic parameters in healthy newborns in the early neonatal period. The authors examined 76 healthy newborns aged up to 7 days. 12 (15.7%) of 76 children were diagnosed with intrauterine growth retardation of hypotrophic type and 14 children (18.49%) were premature. The authors evaluated the diameter of the outgoing tract of the left ventricle, pulmonary artery trunk, mitral and tricuspid valve rings. The disc method was used to determine the final diastolic volume of the left ventricle. The pulse Doppler was used to determine the integrated flow rate in the outflow tract of the left ventricle, the pulmonary artery trunk, on the mitral and tricuspid valves. After US there were calculated the stroke volume index, cardiac index, total peripheral vascular resistance and oxygen delivery index. The results. It integral flow rate was found to be a key indicator of central hemodynamics, which determines the magnitude of the stroke volume. Body weight and the presence of functioning fetal communications do not have a significant impact on the indexed systemic blood flow in healthy newborns. There is a direct correlation between the integral blood flow velocity and the stroke volume index, which is characteristic of all intracardiac anatomical structures.

Increased Aldosterone Release During Head-Up Tilt in Early Primary Hypertension.

Hyperaldosteronism is well known cause of secondary hypertension. However, the importance of aldosterone for the much larger group of patients with primary hypertension is less clear. We hypothesized that in young subjects with primary hypertension, the rise of plasma aldosterone levels in response to head-up tilt testing as a stress stimulus is exaggerated. Hemodynamics (blood pressure (BP), heart rate (HR), cardiac index (CI), and total peripheral vascular resistance index (TPRI), all by TaskForce monitor) and hormones (plasma renin activity (PRA), angiotensin II (Ang II), aldosterone) were measured before and during 30 minutes of head-up tilt in 45 young hypertensive and 45 normotensive subjects. BP, HR, CI, and TPRI all increased in response to head-up tilt, with no difference between groups. There was no difference in baseline PRA, Ang II, and aldosterone between groups. During head-up tilt, PRA, and Ang II levels increased similarly. However, aldosterone levels increased to a greater extent in the hypertensive vs. normotensive subjects (P = 0.0021). Our data suggest that an increased release of aldosterone in response to orthostatic stress is a feature of early primary hypertension. The similar increase in PRA and Ang II suggests a potential role for secretagogues of aldosterone other than Ang II in this response. In addition to its established role in secondary hypertension, dysregulation of aldosterone release might contribute to the development of primary arterial hypertension.

Cardiopulmonary parameters in propofol- or thiopental-anesthetized dogs induced to pulmonary hypertension by serotonin

ABSTRACTThe cardiopulmonary changes in propofol- or thiopental-anesthetized dogs induced to pulmonary hypertension (PH) were evaluated. Twenty adult animals were randomly assigned to two groups: propofol group (PG) and thiopental group (TG). In PG, propofol was used for induction (8(0.03mg.kg-1) and anesthesia maintenance (0.8mg.kg-1.minute-1), while, in TG, thiopental was used (22±2.92mg.kg-1; 0.5mg.kg-1.minute-1, respectively). Mechanical ventilation using time cycle was started. PH was induced by administration of serotonin (5HT) (10µg.kg-1 and 1mg.kg-1.hour-1) through a thermodilution catheter positioned in the pulmonary artery. The measurements were performed before administration of 5HT (T0), after 30 minutes (T30), then at 15-minute intervals (T45, T60, T75 and T90). No differences between groups were registered for systolic (sPAP) and mean pulmonary arterial pressure (mPAP), mean arterial pressure (MAP), total peripheral resistance index (TPRI) and pulmonary vascular resistance index (PVRI). In PG, sPAP and mPAP increased from T30. While in TG, sPAP and mPAP increased from T75. In PG, heart rate (HR) increased from T30, in which PG was higher than TG. The TPRI values decreased from T30 in PG, and in TG, at T45, T60 and T90. In PG, at T0, PVRI was lower than at other times. In PG, arterial partial pressures of oxygen (PaO2) decreased from T60 and alveolar-arterial oxygen gradient (PA-aO2) increased at T60. In TG, at T0 PaO2 was higher than at T30, T45, T60 and T90, while PA-aO2 at T0 was lower than at T90. From T30 to T90, TG showed higher PaO2 means and lower arterial partial pressures of carbon dioxide (PaCO2) values when compared to PG. In PG, from T30, PaCO2 increased, while in TG this parameter was stable. In conclusion, thiopental anesthesia attenuated the cardiopulmonary changes resulting from serotonin-induced PH, probably by attenuation of vasoconstriction and bronchoconstriction.

EFFICIENCY OF TRANSPULMONARY THERMODILUTION IN THE OPTIMIZATION OF INTENSIVE TREATMENT IN PATIENTS WITH SEVERE NOSOCOMIAL PNEUMONIA

Objective: to evaluate the efficiency of transpulmonary thermodilution (TPTD) for the choice of measures to correct hemodynamics in patients with severe nosocomial pneumonia (NP). Subjects and methods. The investigation enrolled 107 NP patients admitted to an intensive care unit (ICU). Group 1 patients were intensively treated in accordance with a protocol for hemodynamic correction during early goaldirected therapy for sepsis. In Group 2, infusion thera py and sympathomimetic agents were prescribed depending on the results of TPTD. Results. Patients in both groups did not differ in the examined clinical and laboratory indicators. On day 1 of intensive therapy, in Group 2 (a TPTD controlled intensive treatment group) the prescription of sympathomimetic drugs was virtually twice more active than in Group 1; and the value of positive hydrobalance was, twice less. In 5 days, the frequency of use of sympathomimetic agents had no intergroup differences and, in 7 days became less in Group 2 patients. After the therapy patients in Group 2 did not require substantial amounts of infusion and great positive hydrobalance, resulting in lower central venous pressure (CVP) values. After 5 days of intensive therapy, the positive hydrobalance in Group 2 patients was 5 times less and on day 7 this indicator became negative. There were no intergroup differences in CVP on day 1; however, this indicator was higher in Group 1 patients from day 2 to the end of the followup period. At days 5—7, Group 2 patients exhibited elevated SvO2 values and hypolactatemia. At day 3, the SOFA severity was somewhat higher in Group 2 than in Group 1, then substantially reduced and on days 5—7 it was 2—2.5 scores lower in Group 2 than in Group 1. The mortality in ICU was 49% and 33% in Groups 1 and 2, respectively (χχ2=3.899; pConclusion. The determination of infusion amounts and indications for the use of sympathomimetic drugs on the basis of the integrated assessment of global enddiastolic volume index, cardiac index, and total peripheral vascular resistance index results in improved clinical outcomes in mechanically ventilated patients with severe NP. This approach ensures the use of sympathomimetic agents and to avoid hypervolemic loading.

Effects of exercise training on the hemodynamics in patients with chronic heart failure

Background and purpose: It is still unclear physiological mechanisms of preserved exercise-tolerance in patients with stable chronic heart failure, irrespective decreased left ventricular ejection fraction. We tried to investigate underlying mechanisms. Methods: Consecutive 62 patients with stable chronic heart failure under oral medications were enrolled (NYHA II-III). Exercise test was performed on a symptomlimited bicycle ergometer. We analyzed changes in cardiac parameters by means of non-invasive whole body electrical bio-impedance using NICaS apparatus during exercise. Age (yrs, 25%-75% range): 63 (49-72). Ejection Fraction (%): 61 (38- 69). Basic diseases of heart failure: Idiopathic dilated cardiomyopathy 22; Valvular heart disease 22; Old myocardial infarction 15; Congenital heart disease 2; Hypertensive heart disease 1. Results: Comparing before and after exercise, heart rate was significantly increased after exercise, but there were no significant changes in mean blood pressure. While total peripheral vascular resistance index tended to be decreased, cardiac index tended to be increased. Conclusions: There might exist beneficial physiological mechanisms to decrease total peripheral vascular resistance accompanied with increasing cardiac output during exercise in patients with stable chronic heart failure associated with preserved exercise-tolerance. Exercise-induced peripheral vasodilation may underlie

Maintenance of Minute Circulation Volume during Orthotopic Liver Transplantation

Objective: to optimize procedures to maintain minute circulation volume at different stages of orthotopic liver transplantation. Subjects and methods. In the period 2005—2010, Sverdlovsk Regional Clinical Hospital One performed 32 orthotopic liver transplantations, including one retransplantation. The patients’ ASA class was (4—5). The operations were carried out under general anesthesia. The mean duration of surgery was 8.1 (range 5.8—10.5) hours. The investigators applied anesthesia based on iso-fluorane 0.6—0.9 MAC (by monitoring the anesthesia depth index with cerebral state index (CSI-40-60)), as well as extended central hemodynamic monitoring (prepulmonary hemodilution). All the operations were made via portofemoroaxillary bypass, by using a centrifugal Biopump. Eight surgical stages were identified: 1) run-in (after tracheal intubation); 2) liver mobilization; 3) partial bypass; 4) complete bypass (hepatectomy, a liver-free period); 5) reperfusion; 6) a postreperfusion period (bypass end); 7) biliary repair; 8) the end of an operation. The concentrations of blood parameters, electrolytes, acid-base balance, and the levels of lactate and glucose were examined. The data were processed statistically. Central hemodynamics was monitored by prepulmonary thermodilution, by calculating cardiac index (CI), stroke index, and total peripheral vascular resistance index (TPVRI) at the stages: liver mobilization, postreperfusion period (bypass end), and the end of surgery. Results. Even during partial bypass, there was a significant drop in mean blood pressure (MBP) as compared to the baseline levels (p<0.05). Reperfusion was also accompanied by a significant decrease in MBP and an increase in heart rate. At the end of reperfusion and in the postreperfusion period, TPVRI was halved (689.2±68.0) as compared to the baseline levels. In the postreperfusion period, central venous and pulmonary artery pressures were significantly increased by 32 and 21%, respectively. That period was marked by a significant rise in CI. Serum lactate and glucose elevations starting from the complete bypass stage were associated with the liver being excluded from the circulation and cannot be a marker of inadequate tissue perfusion. Conclusion. The decrease in MBP during portofemoroaxillary bypass is associated with hypovolemia and mainly with vasoplegia during reperfusion. Approaches to maintaining the adequate minute circulation volume depend on the surgical stage: sufficient preload is needed during complete bypass and it is expedient to combine an infused load with vasopressors for the correction of the reperfusion syndrome with low TPVR. Key words: liver transplantation, minute circulation volume, general anesthesia, central hemodynamics.

Complex Therapy for Intraoperative Blood Loss during Pelvic Bone Repair

Objective: to introduce blood saving technologies and to develop algorithms for management of patients with pelvic fractures. Subjects and methods. Sixty patients aged 40.6±2.3 years with pelvic fractures were examined. The banking of packed autoerythrocytes and auto freshly frozen plasma (AutoFFP), intraoperative acute hypervolemic hemodilution (AHH), and instrumental reinfusion of washed autoerythrocytes were made in all the patients. Blood loss volume averaged 32.1±1.7 ml/kg. The parameters of central hemodynamics (CH), blood oxygen-transport function, the blood system (red blood cells, hemoglobin, packed cell volume, and platelets) were studied. AutoFFP was transfused in the most traumatic period of surgery, autoblood was on completion of surgical hemostasis, and washed autoerythrocytes were within 3—4 hours after surgery. Postoperative reductions in hemoglobin to below 80 g/l and packed cell volume below 25% are indications for packed autoerythrocyte transfusion. Results. During preoperative autoblood banking, the parameters of CH and the blood system underwent no changes, all variations in the parameters were within the normal range and compensatory. When AHH and instrumental washed erythrocyte reinfusion were conducted, there was a significant increase in cardiac index (CI), stroke index by 37 and 30%, respectively; reductions in total peripheral vascular resistance index by 38%, mean blood pressure by 18%, moderate hypercoagulation, and significant decreases in hemoglobin, packed cell volume, red blood cells by 17, 15, and 18%, respectively. The values of acid-base condition and homeostasis underwent no considerable changes. Arterial blood O2 content was significantly lowered by 16%; however, global O2 uptake remained unchanged at the baseline levels due to the increase of CI by 30% of the baseline level. Conclusion. The application of blood saving technologies, preoperative autoblood banking in particular, AHH, and instrumental washed autoerythrocyte reinfusion allowed a refusal to use allo-geneic blood components during pelvic repair, by preventing the development of hemotransfusion complications. Key words: blood loss, blood saving, packed autoerythrocytes, auto freshly frozen plasma, acute hypervolemic hemodilution, autohemotransfusion, instrumental washed autoerythrocyte reinfusion, spinal epidural anesthesia.

Predictors of the Cardiodepressive Effect of Alveolar Opening Maneuver (Mobilization) in Cardiosurgical Patients

Objective : to reveal the predictors of clinically significant deterioration of cardiac pump function resulting from alveolar opening maneuver (AOM) (mobilization) made early after extracorporeal circulation during standard cardiosurgery. Subjects and methods. Hemodynamic, clinical, and laboratory parameters were analyzed in 20 cardiosurgical patients who had undergone AOM in the early postperfusion period. The study inclusion criteria were a PaO 2 /FiO 2 ratio of less than 350 mm Hg, a cardiac index (CI) of more than 2.5 l/min/m 2 , a dosage of dopamine and/or dobutamine of not more than 10 μg/kg/min, and standard AOM performance (P max , 30—35 cm H 2 O; endexpiratory pressure (PEEP), 13—15 cm H 2 O). Regression analysis was used to identify the predictors of a clinically significant reduction in CI (less than 2.5 l/min/m 2 ). Results . Before and after AOM, CI was 3.1±0.1 and 2.9±0.1 l/min/m 2 , respectively ( p >0.05); however, CI was less than 2.5 l/min/m 2 (2.16±0.09 l/min/m 2 ) in 25% of cases. After AOM, CI values were significantly related to those recorded prior to a respiratory procedure ( p =0.039), total peripheral vascular resistance index (TPVRI) ( p =0.00039), and intrapulmonary blood shunt fraction (Qs/Qt) ( p =0.041). There were no relationships to other record ed and estimated hemodynamic parameters (p>0.1). After AOM, CI values were unrelated (p>0.1) to the duration of extracorporeal circulation, the period of myocardial ischemia, and the used dosages of inotropic agents. The predictor of a clinically significant CI reduction after AOM was the only index TPVRI (p=0.00025) recorded before a respiratory procedure. Following AOM, the probability of a significant CI reduction substantially increased (the approximation coefficient R2=0.75) at TPVRI values of 2000 din•sec•cm-5•m2 or more. Conclusion. After AOM performed in the early period after extracorporeal circulation, CI values are related to the baseline level of CI, TPVRI, and Qs/Qt; however, after this procedure only the value of TPVRI is a reliable predictor of clinically significantly depressed cardiac pump function. The risk of persistent cardiodepression is highest at TPVRI values of 2000 din•sec•cm-5•m2 or more. AOM should be carried out early after extracorporeal circulation in cardiosurgical patients, by making an invasive monitoring that makes it possible to maximally correctly evaluate central hemodynamics, including CI and TPVRI.

Ways of Improving the Results of Treatment for Pulmonary Thromboembolism

Objective: to reveal the predictors of clinically significant deterioration of cardiac pump function resulting from alveolar opening maneuver (AOM) (mobilization) made early after extracorporeal circulation during standard cardiosurgery. Subjects and methods. Hemodynamic, clinical, and laboratory parameters were analyzed in 20 cardiosurgical patients who had undergone AOM in the early postperfusion period. The study inclusion criteria were a PaO2/FiO2 ratio of less than 350 mm Hg, a cardiac index (CI) of more than 2.5 l/min/m2, a dosage of dopamine and/or dobutamine of not more than 10 ^g/kg/min, and standard AOM performance (Pmax, 30—35 cm H2O; end-expiratory pressure (PEEP), 13—15 cm H2O). Regression analysis was used to identify the predictors of a clinically significant reduction in CI (less than 2.5 l/min/m2). Results. Before and after AOM, CI was 3.1±0.1 and 2.9±0.1 l/min/m2, respectively (p&gt;0.05); however, CI was less than 2.5 l/min/m2 (2.16±0.09 l/min/m2) in 25% of cases. After AOM, CI values were significantly related to those recorded prior to a respiratory procedure (p=0.039), total peripheral vascular resistance index (TPVRI) (p=0.00039), and intrapulmonary blood shunt fraction (Qs/Qt) (p=0.041). There were no relationships to other recorded and estimated hemodynamic parameters (p&gt;0.1). &#8211; After AOM, CI values were unrelated (p&gt;0.1) to the duration of extracorporeal circulation, the period of myocardial ischemia, and the used dosages of inotropic agents. The predictor of a clinically significant CI reduction after AOM was the only index TPVRI (p=0.00025) recorded before a respiratory procedure. Following AOM, the probability of a significant CI reduction substantially increased (the approximation coefficient R2=0.75) at TPVRI values of 2000 din^sec^cm-5^m2 or more. Conclusion. After AOM performed in the early period after extracorporeal circulation, CI values are related to the baseline level of CI, TPVRI, and Qs/Qt; however, after this procedure only the value of TPVRI is a reliable predictor of clinically significantly depressed cardiac pump function. The risk of persistent car-diodepression is highest at TPVRI values of 2000 din^sec^cm-5^m2 or more. AOM should be carried out early after extra-corporeal circulation in cardiosurgical patients, by making an invasive monitoring that makes it possible to maximally correctly evaluate central hemodynamics, including CI and TPVRI. Key words: alveolar opening maneuver (mobilization), lung recruitment, recruiting maneuver in cardiosurgical patients, central hemodynamics during lung recruitment, cardiodepression during lung recruitment.

Influence of the 6‑month anemia therapy with erythropoietin on renal function and some hemodynamic parameters in predialysis patients

The aim of this study was to evaluate the influence of a 6-month anemia therapy with recombinant human erythropoietin (rHuEpo) on glomerular filtration rate (GFR) and renal blood flow related to hemoglobin (Hb) concentration, changes in heart function and total peripheral resistance in patients with chronic kidney disease (CKD) treated conservatively. We evaluated 13 patients (9 women and 4 men) aged 64.8 +/- 8.9 years with serum creatinine of 3.82 +/- 1.30 mg/dl and Hb concentration of 10.02 +/- 0.45 g/dl. rHuEpo was given in the mean dose of 2296 +/- 673 U/week s.c. to achieve Hb 12 g/dl. At baseline and after 6 months of rHuEpo therapy echocardiography and renoscintigraphy were performed. After 6 months' therapy Hb increased significantly, while blood pressure did not change significantly. Renal anemia correction led to a decrease in left ventricular end-diastolic dimension index, left ventricular end-diastolic volume index, stroke volume index and cardiac index. Total peripheral vascular resistance index increased significantly. At the same time a significantly reduced left ventricular mass index was observed. Correction of renal anemia and changes in systemic hemodynamics did not exert unfavorable effect on renal hemodynamic parameters. GFR index, blood flow rate index, renal vascular resistance index and filtration fraction remained unchanged. During rHuEpo therapy decline in renal function expressed as 1/serum creatinine did not differ compared with a 6-month period before initiating rHuEpo therapy. Therapy with rHuEpo in patients with stage 3 and 4 CKD with correct blood pressure control does not result in worsening of renal function despite changes in left ventricular function and increase of total peripheral resistance.

Maternal nonpregnant vascular function correlates with subsequent fetal growth

Evidence is accumulating that fetal growth is influenced by preexisting maternal disorder(s) hampering endothelial function. We tested the hypothesis that in nonpregnant normotensive, formerly preeclamptic women, vascular function predicts the development of fetal growth restriction. In 60 formerly preeclamptic women, we measured central hemodynamic and vascular and clotting function mid follicular phase during the menstrual cycle. Inclusion for final analysis required besides normotension, a subsequent singleton pregnancy, established within 1 year after the prepregnant evaluation and ongoing beyond 16 weeks' gestation. In the ongoing pregnancy we determined birth weight and birth weight percentile. Among 60 formerly preeclamptic women, 45 (75%) were normotensive. Thirty-one (69%) participants succeeded in establishing an ongoing pregnancy within 1 year and were included for final analysis. Of the 31 subsequent pregnancies, 8 (26%) were complicated by fetal growth restriction. Prepregnant left and right uterine artery pulsatility index (PI) correlated inversely with carotid artery compliance ( r = 0.57, P = .005, r = 0.62, P = .002) and venous compliance ( r = 0.49, P = .02 and r = 0.45, P = .04, respectively). The latter, in turn, correlates with plasma volume ( r = 0.63, P = .001) and total peripheral vascular resistance index ( r = -0.45, P = .02). Finally, prepregnant left and right uterine artery PI correlated inversely with subsequent achieved fetal growth ( r = -0.68, P < .0001 and r = -0.58, P = .001, respectively). In nonpregnant normotensive, formerly preeclamptic women, an elevated uterine artery PI predisposes to subsequent restriction in fetal growth.

Oxygen Transport Capacity and Hemodynamic Effect of Newly Developed Artificial Blood “Neo Red Cells (NRC)”

The purpose of this study was to evaluate liposome-encapsulated hemoglobin, named Neo Red Cells (NRC), on hemodynamics and oxygen-transport capacity in a blood exchange experiment. The experiment was carried out in nine mongrel dogs. Depending on the percentage of blood exchange with NRC, the animals were divided into two groups; Group I (4 animals with an exchange rate less than 88%), and Group II (5 animals with an exchange rate over 88%). After blood exchange, total peripheral vascular resistance index (TPRI) decreased and cardiac index (CI) increased. These changes were more marked in Group II than in Group I, thus showing that NRC relieved the burden on the heart, probably due to the fact that the viscosity of NRC is 2 cp which is less than 1/3 that of whole blood. The oxygen binding capacity per 1g hemoglobin in NRC was 2-4 times as much as red blood cells. Thus, NRC was superior to natural red blood cells in terms of oxygen transport capacity and its effects on the circulatory system.

Study of effect of the newly developed artificial blood "Neo Red Cells (NRC)" on hemodynamics and blood gas transport in canine hemorrhagic shock.

The purpose of this study is to evaluate the newly developed liposome-encapsulated hemoglobin, named Neo Red Cells (NRC), in the treatment of hemorrhagic shock. The particle size of NRC is 180 +/- 88 nm, the hemoglobin concentration is 5.6 g/dl, the viscosity is 2 cp and P50 is 49.5 mmHg. The experiment was carried out on six mongrel dogs suffering hemorrhagic shock. Blood was extracted from the femoral artery and blood pressure became lower than 60 mmHg. NRC in amount equal to the amount of blood extracted was transfused immediately. Inhalating normal room air, the above manipulation was repeated 3-5 times. After 59% to 88% blood exchange using NRC, the total peripheral vascular resistance index (TPRI) was reduced and the cardiac index (CI) was increased, thereby alleviating the burden on the heart. The reduction of TPRI in the presence of hemorrhagic shock is presumed to be due to the small size of the NRC granules and their low viscosity. As the exchange rate increased, the oxygen consumption (VO2) increased remarkably, presumably due to the increase of CI and A-V difference of oxygen content. The conclusion of the study is that NRC is more suitable than natural blood for the treatment of hemorrhagic shock.

Blood pressure during sleep: Antihypertensive medication

To investigate whether excessive reduction of blood pressure (BP) by antihypertensive medications correlates with myocardial infarction, especially during steep in elderly patients, we used telemetry and cuvette dye-dilution methods to assess the direct BP and the hemodynamics of 68 inpatients with essential hypertension during wakefulness and steep. There were 25 patients ≥60 years old (OH-group) and 43 were ≤59 years old (YH-group). Of the OH-group, 36% showed high BP during the day, with marked decreases (minimum BP <110/70 mm Hg) during steep. Average cardiac index (CI) of the OH-group was low during wakefulness and extremely low during show-wave sleep. Changes of mean BP in the OH-group correlated with changes in total peripheral vascular resistance index (TPRI) during steep, but this correlation was not observed in the YH-group. The antihypertensive effects on nocturnal BP of the various medications was: central adrenergic inhibitors ≤ β blockers with intrinsic sympathomimetic activity ≤ α (αβ) blockers ≤ angiotensin-converting enzyme inhibitors ≤ calcium antagonists. Because BP and CI were found to be very low and TPRI seems to play an important role in BP regulation in sleeping elderly patients, excessive antihypertensive medication may be harmful to this subgroup. However, because the effects on nocturnal BP differ among various antihypertensive treatments, further research is required on the relation between antihypertensive medication and the hemodynamics of sleeping elderly hypertensive patients.

Captopril in patients with type II diabetes and renal insufficiency: Systemic and renal hemodynamic alterations

Purpose: To our knowledge, clinical studies on the long-term use of angiotensin converting enzyme inhibitors in patients with type II diabetes mellitus and nephropathy with incipient renal failure are nonexistent. We therefore assessed the effects of long-term treatment with captopril on systemic and renal hemodynamics and urinary protein excretion in patients with type II diabetes mellitus and the clinical syndrome of diabetic nephropathy. Patients and methods: Twelve patients, 10 men and two women, with an average age of 52 years (range, 40 to 66), participated in the study. After the basal hemodynamic evaluation, the patients received captopril in two daily doses. The dosage was adjusted at weekly intervals in order to obtain normalization of blood pressure without exceeding the maximum allowable dosage. Four patients also received furosemide (20 to 40 mg/day). Results: After six months of treatment, the intra-arterial blood pressure fell (from 162 ± 17 103 ± 5 to 139 ± 26 89 ± 10 mm Hg) due to the reduction in total peripheral vascular resistance index (from 3,720 ± 658 to 3,190 ± 762 dynes/second/cm −5/m 2), with no change in cardiac index (2.78 ± 0.36 to 2.79 ± 0.47 liters/minute/m 2). No significant change was seen in renal vascular resistance (from 30,175 ± 5,371 to 30,173 ± 5,372 dynes/second/cm −5/1.73 m 2) and in filtration fraction (from 26 ± 8 to 27 ± 10 percent). A slight, not significant, decrease in renal plasma flow (from 243 ± 97 to 217 ± 108 ml/minute/1.73 m 2), in glomerular filtration rate (from 57 ± 17 to 51 ± 19 ml/minute/1.73 m 2), and in proteinuria (from 4.50 ± 3.10 to 3.40 ± 2.31 g/day) was also observed. Conclusion: Our findings suggest that captopril is an effective antihypertensive agent in patients with diabetic nephropathy, but the renal beneficial effects seem to be limited when this syndrome is complicated by renal insufficiency.

Increased Cardiovascular Responses to Norepinephrine and Calcium Antagonists in Essential Hypertension Compared with Normotension in Humans

The responses to a supine rest, norepinephrine (NE) and angiotensin II (Ang II) were investigated in the absence and presence of calcium antagonist nifedipine or diltiazem in essential (genetic, arterial) hypertension and normotension in humans. A supine rest significantly decreased blood pressure (BP), heart rate (HR), stroke volume index (SI), and cardiac output index (CI). On the contrary, the rest increased total peripheral vascular resistance index (TPRI) in both normotensives and hypertensives. The decrease in BP was significantly greater in hypertensives than in normotensives. NE significantly increased BP and TPRI, whereas it decreased HR, SI, and CI. The increase in BP was greater in hypertensives than in normotensives. Nifedipine and diltiazem inhibited the NE-induced increases in BP and TPRI. Ang II increased BP and TPRI, but it decreased HR, SI, and CI. Diltiazem did not inhibit the Ang-II-induced increases in both BP and TPRI. The increased responses to a rest and NE were observed in the early stage of essential hypertension. The increased responses may contribute to both the increase in BP and the induction of high blood pressure in essential hypertension. The calcium antagonists inhibited the NE-induced increases in BP and TPR. The results suggest that the antagonists inhibit the NE-dependent calcium influx and calcium release in the arterial smooth muscle. The observed responses to Ang II suggest that the antagonists may not inhibit Ang-II-dependent calcium-channel activity in the smooth muscle.

Hemodynamic response to volume depletion in acutely uremic dogs.

Hemodynamic response to volume depletion by isolated ultrafiltration was compared in uremic (U) and nonuremic (N) conscious dogs. Fluid was removed at a constant rate until mean arterial pressure (MAP) decreased to less than 80 mmHg. Initial MAP was higher in the uremic dogs [132 +/- 8.6 (SD) mmHg] than in nonuremic controls (106 +/- 12, P less than 0.001). Initial cardiac index [U 4.97 +/- 0.831 X min-1 X m-2, N 4.44 +/- 0.62] and total peripheral vascular resistance index [(TPRI) U 2,160 +/- 353 dyn X s X cm-5 X m-2, N 1,976 +/- 420] were slightly, but not significantly, higher in uremic animals. Initial central venous pressure, wedge pressure, and plasma norepinephrine level were greater in the uremic dogs. At the end point of volume depletion, both uremic and nonuremic animals had achieved similar levels of TPRI, despite greatly attenuated or absent increases in plasma renin activity in the uremic group. At end point, blood volumes and plasma norepinephrine levels were comparable. The increase in pulse rate was higher in the uremic animals (59 +/- 37 pulses/min) compared with controls (25 +/- 52, P less than 0.05). In an additional group of uremic dogs, cardiovascular responses to hemorrhage and isolated ultrafiltration were compared and found to be similar, after allowance for blood viscosity changes had been made. The data suggest that in acutely uremic conscious dogs, despite reduced renin-angiotensin responses, hemodynamic adaptation to rapid volume depletion is not impaired.

Echocardiographic hemodynamic study during ultrafiltration sequential dialysis.

4 patients on regular dialysis were studied by the echocardiographic method during ultrafiltration and dialysis performed sequentially according to two different protocols. Blood pressure, heart rate, cardiac output, stroke volume, systolic and diastolic dimension of the left ventricle, systolic and diastolic volumes of the left ventricle, ejection fraction, shortening fraction and total peripheral vascular resistance index were measured. During ultrafiltration there is an increase of the total peripheral vascular resistance index. Myocardial contractility improves only during dialysis. Physiopathologic implications are discussed.