Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intraoperative hypertension is a common problem in patients undergoing myocardial revascularization. Twenty patients who developed acute hypertension after sternotomy were studied. Ten patients received three doses of intravenous nitroglycerin (32, 64, and 96 mcg. per minute), and 10 patients received nitroprusside, (20, 40, and 60 mcg. per minute). All patients were anesthetized with morphine, diazepam, nitrous oxide, oxygen, and pancuronium bromide. Five patients in each group also received enflurane. The study compared the effects of nitroglycerin and nitroprusside on systemic hemodynamics, myocardial oxygen supply/demand relationships, and ischemic changes on the electrocardiogram. Both drugs decreased preload and afterload in a dose-related manner. Heart rate increased significantly only with the largest dose of each drug. Myocardial oxygen demand was decreased significantly by both drugs, while the coronary perfusion pressure was decreased more by nitroprusside. Both nitroglycerin and nitroprusside improved left ventricular performance. Nitroglycerin improved ST-segment depression in eight of 10 patients; while nitroprusside improved the ST segments in six patients, and worsened the ST segments in three patients. None of the nitroglycerin group had worsening of the electrocardiographic ST segments. These findings demonstrate that both drugs can control intraoperative hypertension and can decrease myocardial oxygen demand. Nitroglycerin was shown to improve ischemic changes on the electrocardiogram more often than nitroprusside.
 ...
PMID:Vasodilator therapy during coronary artery surgery. Comparison of nitroglycerin and nitroprusside. 10 11

Nitroglycerin is a vasodilating agent by virtue of its actions on vascular smooth muscle fibers. It may be administered intravenously (using either 5 p. cent dextrose, or propylene-glycol solvant), sublingually, orally or by topical administration. It is rapidly metabolized, principally by liver. Its is not toxic. The vasodilatation that is produced is both arterial and venous and is dose-related in dog (1 microgram to 100 micrograms/kg/min). However, resistance and tachphylaxis may occur. Its principal use is for angor treatment, but it has been used for the treatment of arteriopathy of the lower limbs, biliar hypertony and arterial hypertension. It has been recently administered for the treatment of acute phase of myocardial infarction and during pre, per- and post-operative periods in cardiac surgery, neurosurgery and hip surgery, as myocardial protector or anti-hypertensive agent or hypotensive agent. The absence of toxicity and the rapid reversibility of its cardio-vascular effects which are similar to the effects of sodium nitroprusside are important reasons for its use in anesthesia and cardiac intensive care.
 ...
PMID:[Pharmacology of nitroglycerin (author's transl)]. 11 40

Little is known of the clinical significance of myocardial bridges, which may be recognized angiographically as systolic coronary artery narrowing (SCAN). A retrospective review of a 1 year's experience (313 consecutive coronary arteriograms) revealed 5 patients with SCAN, an incidence of 1.6%. SCAN involved the proximal and/or middle segments of the left anterior descending coronary artery in all patients. It is of particular note that the administration of nitroglycerin noticeably accentuated the SCAN phenomenon in each of 3 patients to whom it was administered. Four of the 5 patients had left ventricular hypertrophy due to hypertrophic cardiomyopathy (2), aortic stenosis (1), and hypertension (1). All 5 patients with the SCAN phenomenon had anginal chest pains, and critical obstructive coronary atherosclerosis was observed in only 2 cases. The other 3 patients showed, otherwise normal coronary arteriograms. Thus, myocardial bridges appear to be angiographically manifest predominantly in patients with cardiac hypertrophy. Nitroglycerin, which accentuates SCAN, might be useful as a provocative test to enhance the angiographic recognition of this phenomenon. The possible role of myocardial bridges in the production of myocardial ischemia warrants further investigation.
 ...
PMID:Myocardial bridges in man: clinical correlations and angiographic accentuation with nitroglycerin. 40 19

In patients ranked ASA 1, laryngoscopy and intubation lead to an average increase in blood pressure of 40 to 50%, and a 20% increase in heart rate. These changes, which are greatest one minute after intubation, last for 5 to 10 min. They are due to sympathetic and adrenal stimulation, which may also result in some arrhythmias. About half the patient with coronary artery disease experience episodes of myocardial ischaemia during intubation when no specific prevention is undertaken. Among the different means available for this, narcotics seem to have a reliable and constant effect, but they may be responsible for postoperative respiratory depression. The protective effect of fentanyl starts at 2 micrograms.kg-1, and is at a maximum at 8 micrograms.kg-1. Lidocaine is the drug used most. Recent studies have questioned its efficacy. In clinical practice, it is particularly effective in preventing the pressor response to tracheal intubation, whatever its route of administration (intravenous or intratracheal), but not the increase in heart rate. Beta blockers with bradycardic, antihypertensive, antiarrhythmic and antiischaemic properties, have been advocated. As opposed to lidocaine, these agents are more effective in preventing the changes in heart rate than the pressor response. Because of their depressor effect on the myocardium, their place still remains to be defined, especially in the cardiac risk patient. Short-acting beta blockers should be preferred. Nitroglycerin is specifically indicated in coronary artery disease. Other agents, such as clonidine or calcium blockers, seem to be less effective or less convenient in preventing the haemodynamic alterations. In clinical practice, prevention will first rely on a sufficient dose of narcotics. In some cases, nitroglycerin or beta blockers may be used so as to decrease the doses of narcotics, without altering their efficacy; however, the risk of hypotension should be constantly borne in mind. If preventing measures have not been taken, short-acting antihypertensive agents (beta blockers, calcium blockers) should be used in patients who develop major hypertension during laryngoscopy and intubation.
 ...
PMID:[Consequences and prevention methods of hemodynamic changes during laryngoscopy and intratracheal intubation]. 135 16

The goal of this study was to determine the role of prostaglandin H2-thromboxane A2 (PGH2-TxA2) in altered responses of cerebral arterioles during chronic hypertension. Diameter of pial arterioles was measured during suffusion with ADP, acetylcholine, and nitroglycerin using intravital microscopy in Wistar-Kyoto (WKY) normotensive rats and spontaneously hypertensive rats (SHR) (8-10 mo old). ADP (100 microM) increased pial arteriolar diameter by 21 +/- 3% (means +/- SE) in WKY and only by 7 +/- 3% in SHR. Acetylcholine (10 microM) increased diameter 10 +/- 2% in WKY and, in contrast, reduced diameter 7 +/- 3% in SHR. Nitroglycerin produced similar vasodilatation in WKY and SHR. We then examined whether impaired dilatation of cerebral arterioles in SHR to ADP and acetylcholine may be related to activation of the PGH2-TxA2 receptor. SQ 29548, a specific PGH2-TxA2 receptor antagonist, restored vasodilatation in response to ADP in SHR toward that observed in WKY and reversed vasoconstriction to vasodilatation in response to acetylcholine in SHR. SQ 29548 did not alter responses in WKY. Thus these findings suggest that impaired responses of cerebral arterioles to ADP and acetylcholine during chronic hypertension may be related to the activation of the PGH2-TxA2 receptor.
 ...
PMID:Role of prostaglandin H2-thromboxane A2 in responses of cerebral arterioles during chronic hypertension. 153 13

The nitrovasodilators, nitroglycerin and sodium nitroprusside, cause both arterial and venous smooth muscle dilation by the intracellular release of nitric oxide. Nitric oxide activates guanylate cyclase, resulting in an accumulation of cyclic GMP. The endogenous formation of nitric oxide results in vasodilatory activity similar to the nitrovasodilators. Nitroglycerin is commonly used in the treatment of angina pectoris because of its ability to decrease myocardial oxygen consumption. Most likely, this response occurs as a result of a reduction in preload, which can decrease arterial wall tension and improve coronary blood flow. This pharmacologic effect warrants the use of nitroglycerin in the treatment of myocardial ischemia or infarction, congestive heart failure, and hypertension. Sodium nitroprusside is effective in reducing arterial blood pressure in hypertensive crisis as a result of systemic vasodilation leading to a reduction in preload and afterload. Sodium nitroprusside is not as effective in the treatment of angina pectoris or in diminishing of myocardial ischemia because it does not preferentially improve blood flow to ischemic myocardium over nonischemic myocardium. Inhibition of platelet aggregation has been demonstrated with these drugs, but the clinical applications need further investigation. Nursing interventions for the patient on nitrovasodilator therapy include careful hemodynamic monitoring and drug infusion, along with elimination of physical and emotional stimuli that can aggravate the patient's underlying pathology.
 ...
PMID:Pharmacology of the nitrovasodilators. Antianginal, antihypertensive, and antiplatelet actions. 190 76

The goal of this study was to determine whether responses of the basilar artery to products released by platelets are altered during chronic hypertension. The diameter of the basilar artery was measured using intravital microscopy in normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) (6-8 months old) in response to adenosine 5'-diphosphate (ADP), serotonin, and the thromboxane analogue, U-46619. Dilatation of the basilar artery in response to nitroglycerin was also examined in WKY and SHR. Topical application of ADP (10 and 100 microM) produced only minimal changes in diameter of the basilar artery in WKY (3 +/- 1% and 1 +/- 1%, respectively) and SHR (-0.5 +/- 2% and -2 +/- 3%, respectively) (P greater than 0.05 vs WKY). Nitroglycerin, however, produced potent vasodilatation in WKY and SHR. Constriction of the basilar artery in response to serotonin was potentiated in SHR compared to WKY. Serotonin (0.1 and 1.0 microM) constricted the basilar artery by 11 +/- 2% and 20 +/- 2%, respectively, in WKY and by 29 +/- 3% and 40 +/- 3%, respectively, in SHR (P less than 0.05 vs WKY). In contrast, the thromboxane analogue (U-46619) (0.1 and 1.0 microM) produced similar constriction of the basilar artery in WKY (13 +/- 1% and 18 +/- 2%, respectively) and in SHR (14 +/- 3% and 21 +/- 6%, respectively). Thus, augmented vasoconstriction during chronic hypertension was specific for serotonin. Next, we examined the role of the cyclooxygenase pathway in responses of the basilar artery to ADP and serotonin.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Responses of the basilar artery to products released by platelets during chronic hypertension. 190 15

Hypertensive patients have reduced lymphocyte beta-adrenergic responsiveness which is corrected by a low sodium (Na) diet. To determine if this represents a more generalized abnormality in beta adrenoceptor response, we studied beta adrenergic-mediated vasodilation in hand veins of borderline hypertensive subjects and controls. Subjects received a 5-d diet containing high Na/low potassium (K), high Na/high K, or low Na/high K. Venous distension, as evaluated by a linear variable differential transformer, was measured in relation to infusion of phenylephrine followed by isoproterenol and nitroglycerin. On both the high Na/high K and high Na/low K diets, hypertensive subjects had significantly decreased isoproterenol-mediated vasodilation (47% decrease, P less than 0.01 and 36% decrease, P less than 0.01, respectively). On the low Na/high K diet, isoproterenol-mediated vasodilation in hypertensive subjects increased 41% (P less than 0.01) to a level not different from controls. Nitroglycerin-mediated vasodilation was not different in normotensive and hypertensive subjects, nor was it altered with Na intake. Phenylephrine-mediated vasoconstriction did not differ between normotensive and hypertensive groups. Venous beta-adrenergic response correlated with lymphocyte beta adrenoceptor density in normotensive (r = 0.53, P less than 0.005) but not hypertensive subjects. This study demonstrates that beta-adrenergic responsiveness is selectively reduced in peripheral veins of borderline hypertensive subjects, and this is corrected by a low Na diet. In view of our previous findings of reduced lymphocyte beta-adrenergic responsiveness in borderline hypertension, these studies suggest a generalized defect of beta adrenoceptor responsiveness in human hypertension. Further, dietary Na may play an important role in regulating this abnormality.
 ...
PMID:Defective venous beta-adrenergic response in borderline hypertensive subjects is corrected by a low sodium diet. 215 21

We had a rare patient for adrenalectomy who had aldosteronism complicated with hypertrophic cardiomyopathy (HCM). It has been suggested that aldosteronism could be the cause of HCM. The association is not clear in this case, but there is a possibility that myocardial hypertrophy was deteriorated with hypertension caused by aldosteronism. Two important points of the anesthetic management of a patient with HCM are (1) to prevent direct or reflex increases in contractility, and (2) to maintain adequate preload and afterload. In a case complicated with aldosteronism, there is a risk that a significant increase in peripheral vascular resistance following the manipulation of the adrenal gland would aggravate left ventricular pressure load, resulting in a marked decrease in cardiac output. Therefore, in such a case, vasodilators which are said to be poorly tolerated in a patient with HCM might be considered to facilitate the anesthetic management, provided that the vascular system is kept appropriately full. In this case, we employed enflurane-oxygen-nitrous oxide with fentanyl to keep deep levels of general anesthesia. Nitroglycerin (NTG) was used when arterial pressure increased suddenly with the manipulation of the adrenal gland. The effect of NTG is not definitely convincing since blood pressure returned to normal after adrenal excision. But the fact that pulmonary capillary wedge pressure decreased with infusion of NTG suggests improvement of hemodynamic function.
 ...
PMID:[Anesthetic management of adrenalectomy in a patient with aldosteronism complicated with hypertrophic cardiomyopathy]. 238 99

Arterial hypertension after cardiac surgery is common and is associated with increased morbidity. Glyceryl trinitrate may be a more suitable agent for control of hypertension than sodium nitroprusside. We have developed a closed-loop system for the Atari 1040ST microcomputer to control arterial pressure by the simultaneous infusion of two vasodilators under computer control. Use of this system with glyceryl trinitrate and sodium nitroprusside in 24 patients who required vasodilators after cardiopulmonary bypass, revealed that hypertension was controlled by glyceryl trinitrate alone in 14 of the patients and 10 required supplementary sodium nitroprusside. The results suggest that glyceryl trinitrate is a suitable agent for control of hypertension after cardiac surgery in the majority of patients. They also show that a sizeable minority required additional sodium nitroprusside, and that an automated 'dual pump' system is a satisfactory method of administering two vasodilators in this way.
 ...
PMID:Automatic control of arterial pressure after cardiac surgery. Evaluation of a microcomputer-based control system using glyceryl trinitrate and sodium nitroprusside. 249 2


1 2 3 4 5 6 7 Next >>