Objective：To investigate the influences of urapidil and nicardipine on rabbit sinus function, atrio-ventricular node function and hemodynamics. Methods：Thirty-two Angora＇ s rabbits were selected and randomly divide...Objective：To investigate the influences of urapidil and nicardipine on rabbit sinus function, atrio-ventricular node function and hemodynamics. Methods：Thirty-two Angora＇ s rabbits were selected and randomly divided into four groups. U1 group：urapidil 0.25 mg/kg; U2 group：urapidil 0.5 mg/kg; N1 group：nicardipine 10 μg/kg; N2 group： nicardipine 20 μg/kg. All these medicine were administrated within 30 seconds. Measurements were taken before and after the administration of urapidil or nicardipine for the following data： mean blood pressure（MAP）, heart rate（HR）, sino-atrial conduction time（SACT）, maximal sinoatrial recovery time（SNRTmax） corrected sinus node recovery time（CSNRT）, index of sinus node recovery time（SNRTI）, Wenckebach A-V conduction frequency （WB）, and P-R interval. Results：Significant MAP and HR changes were identified in all of the four groups before and after administration of both urapidil and nicardipine. No significant changes could be found in the rest of the parameters. Intergroup analysis showed that SACT and CSNRT of N1 and N2 groups were shorter than those of the U2 group（P 〈 0.01）; the MAP decreased（P 〈 0.01） and the HR increased drastically（P〈 0.01）. Conclusions：Neither urapidil（0.25 mg/kg, 0,5 mg/kg） nor nicardipine（10 μg/kg, 20 μg/kg） has any significant influence on rabbit sinus function or rabbit atrio-ventricular node function. Nicardipine could be a better choice than urapidil for parafunctional sinus node patients.展开更多
Background The hemodynamics and oxygenation severely fluctuated during the offpump coronary artery bypass grafting (OPCABG) This study aimed at investigating whether or not nicardipine combined with esmolol (1∶10) ca...Background The hemodynamics and oxygenation severely fluctuated during the offpump coronary artery bypass grafting (OPCABG) This study aimed at investigating whether or not nicardipine combined with esmolol (1∶10) can maintain systemic and tissue oxygenation during OPCABGMethods Twenty patients scheduled for OPCABG were divided ramdomly into Group nicardipine (N) and Group nitroglycerine (X) respectively combined with esmolol (E) (Dosage ratio: 1 to 10) (Group N+E and Group X+E) with 10 patients in each group The mixed solution of N+E or X+E were titrated to maintain mean arterial blood pressure between 70 and 80 mmHg following anesthesia induction The variables of hemodynamics, arterial blood lactate content (Lac) and gastric intramucosal partial pressure of carbon dioxide were measured at the following time points: after induction of anesthesia (T1), prerevascularization (T2), grafting of left anterior descending (T3), right coronary descending (T4) and left coronary circumflexus branches (T5), postrevascularization (T6), the end of operation (T7) The delivery of oxygen (DO2), consumption of oxygen (VO2) and gastric intramucosal pH (pHi) were calculatedResults The cardiac index (CI) in Group N+E was significantly increased (P<005) as compared with T1 during OPCABG, while it was mildly decreased in Group X+E The stroke volumes at T4, T5 in Group N+E and at T3T6 in Group X+E were significantly decreased (P<005) The systemic vascular resistance indices in Group N+E were significantly decreased as compared with T1 (P<005) The heart rates in these two Groups were significantly elevated intraoperatively (P<005) The DO2 after the infusion of N+E was significantly increased (P<005) or leveled to T1, and the Lac were within the normal range But the DO2 in Group X+E was decreased throughout the procedure, reaching significant level at T5 (P<005), and the Lac was significantly increased beyond normal range (P<005) The pHi in Group N+E was maintained above 735 during OPCABG, while it was less than 735 from T4 to T7 in Group X+EConclusion Nicardipine combined with esmolol (1∶10) regimen may maintain systemic and tissue oxygenation during OPCABG展开更多
Background Coronary endothelial shear stress （ESS） triggered the development of atherosclerosis. However, the effect of calcium channel antagonist on the distribution of ESS remained unclear. Methods Twenty consecut...Background Coronary endothelial shear stress （ESS） triggered the development of atherosclerosis. However, the effect of calcium channel antagonist on the distribution of ESS remained unclear. Methods Twenty consecutive patients with acute coronary syndrome （ACS） 48 hours after maximal medication with single left anterior descending artery stenosis 〈50% were studied. Nicardipine was intravenously injected at 1 μg/kg after a bolus of 10 mg in order to achieve mean blood pressure （MBP） reduced by 10% or more, or the heart rate increased by 10-15 beats/min. Hemodynamic variables and angiogram at baseline and during injection of nicardipine were recorded, respectively. Coronary artery 3-D reconstruction was used for the analysis of ESS. Results Distal reference-vessel-diameter and minimal lumen diameter decreased significantly from （2.42±0.41） mm and （1.47±0.49） mm at baseline to （2.22±0.35） mm and （1.35±0.49） mm at maximal drug-dosage （P=0.018 and 0.020, respectively）. Nicardipine did not change blood velocity. Lowest mean shear stress at segments 2-mm distal to plaque increased significantly from （0.034±0.519） Pa at baseline to （0.603±0.728） Pa （P=0.013） at peak effect of drug. Conclusions Nicardipine was associated with the constriction of diseased vessel segment that adapted to the reduction of blood pressure, without dynamic change of blood velocity at each stage of whole cardiac cycle. Increased ESS value at segments distal to plaque reflected the cardioprotection by nicardipine （ChiCTR-TRC-10000964）.展开更多
Hypertensive crises are elevations of blood pressure higher than 180/120 mmHg. These can be urgent or emergent, depending on the presence of end organ damage. The clinical presentation of hypertensive crises is quite ...Hypertensive crises are elevations of blood pressure higher than 180/120 mmHg. These can be urgent or emergent, depending on the presence of end organ damage. The clinical presentation of hypertensive crises is quite variable in elderly patients, and clinicians must be suspicious of non-specific symptoms. Managing hypertensive crises in elderly patients needs meticulous knowledge of the pathophysiological changes in them, pharmacological options, pharmacokinetics of the medications used, their side effects, and their interactions with other medications. Clevidipine, nicardipine, labetalol, esmolol, and fenoldopam are among the preferred choices in the elderly due to their efficacy and tolerability. Nitroprusside, hydralazine, and nifedipine should be avoided, unless there are no other options available, due to the high risk of complications and unpredictable responses.展开更多
Hypertension is a common clinical problem in the elderly worldwide and physicians of all types are likely to encounter patients with hypertensive urgencies and emergencies in these patients. Although various terms hav...Hypertension is a common clinical problem in the elderly worldwide and physicians of all types are likely to encounter patients with hypertensive urgencies and emergencies in these patients. Although various terms have been applied to these conditions, they are all characterized by acute elevations in blood pressure and evidence of end-organ injury. Prompt, but carefully considered therapy is necessary to limit morbidity and mortality. A wide range of pharmacologic alternatives are available to the practitioner to control blood pressure and treat complications in these patients. The management of the elderly patient with hypertensive crises needs to include close monitoring and a gentle decline in blood pressure to avoid catastrophic complications, exacerbation of ischemic myopathy, and vascular insufficiency.展开更多
文摘Objective：To investigate the influences of urapidil and nicardipine on rabbit sinus function, atrio-ventricular node function and hemodynamics. Methods：Thirty-two Angora＇ s rabbits were selected and randomly divided into four groups. U1 group：urapidil 0.25 mg/kg; U2 group：urapidil 0.5 mg/kg; N1 group：nicardipine 10 μg/kg; N2 group： nicardipine 20 μg/kg. All these medicine were administrated within 30 seconds. Measurements were taken before and after the administration of urapidil or nicardipine for the following data： mean blood pressure（MAP）, heart rate（HR）, sino-atrial conduction time（SACT）, maximal sinoatrial recovery time（SNRTmax） corrected sinus node recovery time（CSNRT）, index of sinus node recovery time（SNRTI）, Wenckebach A-V conduction frequency （WB）, and P-R interval. Results：Significant MAP and HR changes were identified in all of the four groups before and after administration of both urapidil and nicardipine. No significant changes could be found in the rest of the parameters. Intergroup analysis showed that SACT and CSNRT of N1 and N2 groups were shorter than those of the U2 group（P 〈 0.01）; the MAP decreased（P 〈 0.01） and the HR increased drastically（P〈 0.01）. Conclusions：Neither urapidil（0.25 mg/kg, 0,5 mg/kg） nor nicardipine（10 μg/kg, 20 μg/kg） has any significant influence on rabbit sinus function or rabbit atrio-ventricular node function. Nicardipine could be a better choice than urapidil for parafunctional sinus node patients.
文摘Background The hemodynamics and oxygenation severely fluctuated during the offpump coronary artery bypass grafting (OPCABG) This study aimed at investigating whether or not nicardipine combined with esmolol (1∶10) can maintain systemic and tissue oxygenation during OPCABGMethods Twenty patients scheduled for OPCABG were divided ramdomly into Group nicardipine (N) and Group nitroglycerine (X) respectively combined with esmolol (E) (Dosage ratio: 1 to 10) (Group N+E and Group X+E) with 10 patients in each group The mixed solution of N+E or X+E were titrated to maintain mean arterial blood pressure between 70 and 80 mmHg following anesthesia induction The variables of hemodynamics, arterial blood lactate content (Lac) and gastric intramucosal partial pressure of carbon dioxide were measured at the following time points: after induction of anesthesia (T1), prerevascularization (T2), grafting of left anterior descending (T3), right coronary descending (T4) and left coronary circumflexus branches (T5), postrevascularization (T6), the end of operation (T7) The delivery of oxygen (DO2), consumption of oxygen (VO2) and gastric intramucosal pH (pHi) were calculatedResults The cardiac index (CI) in Group N+E was significantly increased (P<005) as compared with T1 during OPCABG, while it was mildly decreased in Group X+E The stroke volumes at T4, T5 in Group N+E and at T3T6 in Group X+E were significantly decreased (P<005) The systemic vascular resistance indices in Group N+E were significantly decreased as compared with T1 (P<005) The heart rates in these two Groups were significantly elevated intraoperatively (P<005) The DO2 after the infusion of N+E was significantly increased (P<005) or leveled to T1, and the Lac were within the normal range But the DO2 in Group X+E was decreased throughout the procedure, reaching significant level at T5 (P<005), and the Lac was significantly increased beyond normal range (P<005) The pHi in Group N+E was maintained above 735 during OPCABG, while it was less than 735 from T4 to T7 in Group X+EConclusion Nicardipine combined with esmolol (1∶10) regimen may maintain systemic and tissue oxygenation during OPCABG
文摘Background Coronary endothelial shear stress （ESS） triggered the development of atherosclerosis. However, the effect of calcium channel antagonist on the distribution of ESS remained unclear. Methods Twenty consecutive patients with acute coronary syndrome （ACS） 48 hours after maximal medication with single left anterior descending artery stenosis 〈50% were studied. Nicardipine was intravenously injected at 1 μg/kg after a bolus of 10 mg in order to achieve mean blood pressure （MBP） reduced by 10% or more, or the heart rate increased by 10-15 beats/min. Hemodynamic variables and angiogram at baseline and during injection of nicardipine were recorded, respectively. Coronary artery 3-D reconstruction was used for the analysis of ESS. Results Distal reference-vessel-diameter and minimal lumen diameter decreased significantly from （2.42±0.41） mm and （1.47±0.49） mm at baseline to （2.22±0.35） mm and （1.35±0.49） mm at maximal drug-dosage （P=0.018 and 0.020, respectively）. Nicardipine did not change blood velocity. Lowest mean shear stress at segments 2-mm distal to plaque increased significantly from （0.034±0.519） Pa at baseline to （0.603±0.728） Pa （P=0.013） at peak effect of drug. Conclusions Nicardipine was associated with the constriction of diseased vessel segment that adapted to the reduction of blood pressure, without dynamic change of blood velocity at each stage of whole cardiac cycle. Increased ESS value at segments distal to plaque reflected the cardioprotection by nicardipine （ChiCTR-TRC-10000964）.
文摘Hypertensive crises are elevations of blood pressure higher than 180/120 mmHg. These can be urgent or emergent, depending on the presence of end organ damage. The clinical presentation of hypertensive crises is quite variable in elderly patients, and clinicians must be suspicious of non-specific symptoms. Managing hypertensive crises in elderly patients needs meticulous knowledge of the pathophysiological changes in them, pharmacological options, pharmacokinetics of the medications used, their side effects, and their interactions with other medications. Clevidipine, nicardipine, labetalol, esmolol, and fenoldopam are among the preferred choices in the elderly due to their efficacy and tolerability. Nitroprusside, hydralazine, and nifedipine should be avoided, unless there are no other options available, due to the high risk of complications and unpredictable responses.
文摘Hypertension is a common clinical problem in the elderly worldwide and physicians of all types are likely to encounter patients with hypertensive urgencies and emergencies in these patients. Although various terms have been applied to these conditions, they are all characterized by acute elevations in blood pressure and evidence of end-organ injury. Prompt, but carefully considered therapy is necessary to limit morbidity and mortality. A wide range of pharmacologic alternatives are available to the practitioner to control blood pressure and treat complications in these patients. The management of the elderly patient with hypertensive crises needs to include close monitoring and a gentle decline in blood pressure to avoid catastrophic complications, exacerbation of ischemic myopathy, and vascular insufficiency.
