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At least 19 recordsLinked to original sources

PubMed1979

Labetalol in controlled hypotension: administration of labetalol when adequate hypotension is difficult to achieve.

A study of controlled hypotension was undertaken in 50 major surgical patients using labetalol, a drug with both alpha- and beta-adrenoceptor blocking activity. The patients were such that difficulty in achieving controlled hypotension could be anticipated: the young, the anxious and those for whom halothane was contraindicated. The administration of labetalol quickly induced hypotension which was controlled easily and was rapidly antagonized.

Adolescent↗

PubMed1979

[The effects of halothane-, nitroprusside- and trimethaphan-induced hypotension on cerebral blood flow and intracranial pressure (author's transl)].

Arterial hypotension to about 50 mm Hg mean pressure was induced in anaesthetized and artificially ventilated dogs by halothane, nitroprusside, and trimethaphan to study their effects on cerebral blood flow and intracranial pressure during hypotension. During nitroprusside induced hypotension there was a 32% increase in cerebral blood flow above control and a marked decrease in cerebral arteriovenous oxygen content difference indicating luxury perfusion of the brain. Cerebral blood flow remained high even 30 min after termination of hypotension. During halothane and trimethaphan hypotension cerebral blood flow remained unchanged. In all groups epidural pressure did not change substantially during hypotension but increased during recovery from nitroprusside hypotension by a maximum of 72% above control. It is concluded that during and after nitroprusside hypotension loss of cerebral autoregulation occurs which may result in a marked rise in intracranial pressure. Special vulnerability seems to exist shortly after termination of induced hypotension when arterial pressure begins to rise and brain perfusion follows a pressure-flow relationship.

Animals↗

PubMedDate not supplied

Deep controlled hypotension with sodium nitroprusside in the surgical treatment of intracranial arterial aneurysms.

The authors report 73 cases of intracranial arterial aneurysms operated on under deep controlled hypotension--i.e. hypotension below 60 mmHg of systolic arterial pressure (s.a.p.)--. Deep hypotension was induced by Sodium Nitroprusside (SNP). No problems were encountered in order to reach or to maintain deep hypotension. SNP showed to be an easy hypotensive agent, without toxicity at the recommended dosage. Fifty-nine patients were operated on between 40 and 25 mmHg of s.a.p. In 55 patients deep hypotension lasted for 30 minutes or more, reaching 2 hours in 3 patients. Surgical results were excellent, in regard either to the control of bleeding, either to the dissection of the aneurysm. Clinical results were evaluated by comparison with 146 patients operated on under normal pressure (group of control); no complications were clearly related to deep hypotension per se. However, the authors stress the risks of deep hypotension in early surgery, due to the possible association to vascular spasm.

Blood Pressure↗

PubMed2025

Finerenone-Related Risk of Hypotension in Heart Failure With Mildly Reduced or Preserved Ejection Fraction.

BACKGROUND: The nonsteroidal mineralocorticoid receptor antagonist finerenone reduces clinical events in heart failure with mildly reduced ejection fraction/preserved ejection fraction; however, the implications of treatment-related hypotension are unknown. OBJECTIVES: The authors investigated predictors of systolic blood pressure (SBP) <100 mm Hg and investigator-reported hypotension and their associations with randomized treatment and clinical outcomes in the FINEARTS-HF (Study to Evaluate the Efficacy [Effect on Disease] and Safety of Finerenone in Participants With Heart Failure and Left Ventricular Ejection Fraction [Proportion of Blood Expelled Per Heart Stroke]) trial. METHODS: FINEARTS-HF was a randomized, placebo-controlled trial of finerenone in symptomatic patients with chronic heart failure (left ventricular ejection fraction ≥40%). Predictors of SBP <100 mm Hg and hypotension were identified using Cox models. Associations between SBP <100 mm Hg and hypotension, treatment, and clinical outcomes were evaluated using time-updated Cox models. The primary outcome was a composite of total heart failure events and cardiovascular death. RESULTS: Among the 5,815 participants with available data, post-baseline SBP <100 mm Hg occurred in 899 (538 with finerenone vs 361 with placebo; odds ratio: 1.60; 95% CI: 1.38-1.85) and investigator-reported hypotension in 364 patients (225 with finerenone vs 139 with placebo; odds ratio: 1.67; 95% CI: 1.34-2.08). Participants experiencing SBP <100 mm Hg had lower baseline SBP, were older, had higher N-terminal pro-B-type natriuretic peptide levels, a history of smoking, and no diabetes. Treatment-related risk of the primary endpoint was reduced in patients with no/before SBP <100 mm Hg (rate ratio: 0.78; 95% CI: 0.67-0.90) and appeared to attenuate afterwards (rate ratio: 0.99; 95% CI: 0.70-1.39), although no formal statistical interaction was observed (Pinteraction = 0.33). CONCLUSIONS: In this prespecified analysis of the FINEARTS-HF trial, finerenone led to higher rates of post-baseline SBP <100 mm Hg and investigator-reported hypotension. Although hypotension should not prompt automatic treatment discontinuation, these patients should be carefully monitored. (Study to Evaluate the Efficacy (Effect on Disease) and Safety of Finerenone in Participants With Heart Failure and Left Ventricular Ejection Fraction (Proportion of Blood Expelled Per Heart Stroke) Greater or Equal to 40% [FINEARTS-HF]; NCT04435626).

Humans↗

PubMed1979

Effect of reticuloendothelial blockade on the development of hypotension after trauma, sepsis, and intravascular coagulation.

Numerous studies have demonstrated that reticuloendothelial system (RES) depression induced by colloid blockade increases susceptibility to circulatory shock following trauma and sepsis. Recent data have suggested that this may relate to the failure of the RES to clear potentially embolic material derived from activation of the hemostatic system. The present study thus compared the hypotensive response precipitated by trauma or sepsis with that resulting from induction of intravascular coagulation. Mean arterial blood pressure (MABP) was monitored for 120 minutes after sublethal NCD trauma and after intra-aortic injection of live E coli (approximately 10(10) organisms per rat), E coli endotoxin (0.1 mg/100 gm), or bovine thrombin (10 units/100 gm) in 400-500 gm rats 30 minutes after RE blockade (50 mg/100 gm gelatinized lipid colloid) or saline injection. All rats were anesthetized with sodium pentobarbital. No hypotension was observed in blockaded control rats. After trauma, MABP decreased by 20 minutes after injury and recovered to normal levels by 1 hour post-trauma. MABP decreased in blockaded rats after trauma and remained diminished through 2 hours. After live E coli endotoxin or thrombin, both the normal and the blockaded groups underwent an initial hypotension of similar magnitude. A second period of hypotension was much more pronounced in the RE-blockaded animals. Reduced MABP persisted in these animals through 2 hours. These data indicate that RE blockade enhances the hypotensive response to intravascular coagulation and that resulting from trauma or sepsis. This effect was especially apparent during the second phase of hypotension during sepsis and intravascular coagulation. It was suggested that the RES manifests some protective effect against the agents inducing this secondary hypotensive response.

Animals↗

PubMed1975

Factors predisposing to postural hypotensive symptoms in the treatment of high blood pressure.

Symptoms due to orthostatic and exertional hypotension occurred in 23-4 per cent of 448 hypertensive patients treated with guanethidine, debrisoquine, or bethanidine. Symptoms were significantly more frequent in patients treated with guanethidine than in those treated with bethanidine or debrisoquine. Women rather than men and patients with radiological evidence of cardiomegaly, electrocardiographic evidence of left ventricular hypertrophy, or ST/T wave changes, developed these symptoms significantly more often than other patients. A raised blood urea was found more frequently in patients with postural hypotensive symptoms. Characteristically guanethidine produced early morning postural hypotensive symptoms, wheras hypotensive symptoms caused by bethanidine and debrisoquine occurred at other times of the day and particularly one to two hours after tablet ingestion. Debrisoquine and guanethidine had a significantly greater negative chronotropic effect than bethanidine. It is suggested that negative chronotropic effects of these drugs may potentiate hypotensive symptoms in patients with cardiovascular, renal, or cerebrovascular disease. It should be possible to minimize symptoms of postural hypotension by attention to predisposing factors and selection of treatment accordingly.

Bethanidine↗

PubMed1976

Treatment of neurogenic orthostatic hypotension with a monoamine oxidase inhibitor and tyramine.

Six patients with neurogenic orthostatic hypotension were treated with a chemical preparation of tyramine and tranylcypromine ("Parnate"), a monoamine oxidase inhibitor (M.A.O.I.). Four had autonomic failure with no other neurological deficit (idiopathic orthostatic hypotension), and in two patients other neuronal systems were also involved (Shy-Drager syndrome). Previous therapy with fludrocortisone, ephedrine, elastic garments, postural training, and, in one patient, an anti-G suit was unsatisfactory. Tyramine given orally with tranylcypromine produced a moderate rise in blood-pressure which was sustained for 2-4 hours, enabling patients to walk about without symptoms of orthostatic hypotension. Measurement of circulating adrenaline and noradrenaline during therapy suggested that release of noradrenaline caused the pressor response. In three patients there has been a pronounced improvement for 8, 20 and 30 months. In a further patient, therapy has been successful in treating the orthostatic hypotension, although his mobility has been restricted by cerebellar ataxia. In one patient a confusional state developed during treatment and therapy was stopped. The only patient in whom the drugs did not produce a pressor response had orthostatic hypotension with failure of noradrenaline release. It is suggested that the pressor response to a M.A.O.I. and tyramine should be examined in patients with neurogenic orthostatic hypotension and that this treatment should be tried in those who respond.

Administration, Oral↗

PubMed1977

The role of the false neurotransmitter octopamine in the hypotension of fulminant hepatic failure.

1. An investigation was carried out into the mechanism of unexplained hypotension in patients with fulminant hepatic failure. The cardiac output and peripheral resistance were compared in normotensive and hypotensive patients. In addition, the serum concentration of the false neurotransmitter octopamine and the pressor response to noradrenaline, and to the indirectly acting sympathomimetic agent tyramine, were measured in hypotensive and normotensive patients with fulminant hepatic failure and in healthy subjects. 2. The cardiac output and the peripheral resistance were decreased in the hypotensive patients, and their mean heart rate was slower than in the normotensive patients. Although the serum octopamine concentration was significantly elevated in the patients compared with the control subjects, the highest octopamine concentrations were unexpectedly found in the normotensive patients and a significant positive correlation could be demonstrated between the resting blood pressure and the serum octopamine concentration. The pressor response to tyramine and noradrenaline were similar in the hypotensive patients, the normotensive patients and control subjects. 3. These results suggest that neither increased serum concentrations of the false neurotransmitter octopamine, nor end-organ insensitivity to released noradrenaline are responsible for the hypotension. A more likely explanation is toxic depression of the vasomotor centre. The opening of peripheral arteriovenous shunts, possibly as a result of endotoxaemia, might be an additional factor.

Cardiac Output↗

PubMed1979

Occurrence of short-duration hypotensive phospholipid from dog peritoneal dialysate.

From the total lipid fraction of dog peritoneal dialysate after freeze drying and extraction, a hypotensive phospholipid was isolated through silicic acid, cellulose, and Sephadex LH-20 column chromatography in a pure grade; it showed a single spot on TLC. The purified hypotensive factor, designated as Peritoneal Dialysate Depressor-I, elicited potent depressor responses in anesthetized rats, and its threshold dose was approximately 35 microgram/kg. The material resisted proteases and 15-hydroxyprostanoate oxidoreductase. In mobility on TLC, the hypotensive factor was distinuishable from water-soluble hypotensive substances and also from depressor lipids. Judging from its behavior on TLC and column chromatography during the purification procedure, the hypotensive factor seems to be a choline-containing phospholipid and shows the general characteristics of hysolecithin, except for its potent hypotensive activity, and 2',7'-dichlorofluorescein on TLC. The molar ratio of phosphorusurated ones such as stearic and palmitic acids.

Animals↗

PubMed1978

Adverse reactions to methyldopa with particular reference to hypotension.

Of 26,294 consecutive patients monitored in a comprehensive drug surveillance program, 1067 (4 per cent) received methyldopa for treatment of hypertension. Adverse reactions attributed to methyldopa were reported in 149 patients (14 per cent), the most frequent being hypotension. Life-threatening adverse effects were reported in nine patients (6 per cent of reactors)--the major problems being hypotension associated in several patients with signs of cardiac or cerebral ischemia. Hypotension attributed to methyldopa was more frequent in younger patients, in those with uremia, in lighter subjects, and in those receiving a high daily dose. Marked interaction between these factors was demonstrated and eightfold differences in the frequency of hypotension were observed in different sub-groups of methyldopa recipients. Adverse effects other than hypotension were reported infrequently and did not correlate well with the previously mentioned factors. The findings suggest that methyldopa therapy should be commenced cautiously in younger patients, in the non-obese, and in those with impairment of renal function as manifest by elevated blood urea nitrogen levels.

Adult↗

PubMed1979

The pathogenesis of hyperadrenergic postural hypotension in diabetic patients.

Patients with diabetes generally exhibit normal plasma catecholamine responses to standing. Some have blunted norepinephrine responses and postural hypotension-hypoadrenergic postural hypotension due to classic diabetic adrenergic neuropathy. Others, including some with postural hypotension, have exaggerated norepinephrine responses to standing. In order to clarify the pathogenesis of this hyperadrenergic state which occurs in a subset of diabetic patients, we studied aldosterone secretion, vascular and metabolic responsiveness to the administration of norepinephrine, and intravascular volumes in four diabetic patients who were selected for their exaggerated plasma norepinephrine responses to standing. Three of the four patients also exhibited (hyperadrenergic) postural hypotension. None of the hyperadrenergic diabetic patients had evidence of hypoaldosteronism or vascular resistance to norepinephrine, but all four patients had subnormal red blood cell masses and the mean (+/-SE) red blood cell mass (13.1 +/- 1.0 ml/kg) was approximately half of that of age- and sex-matched diabetic controls (26.5 +/- 2.7 ml/kg, p less than 0.01). Thus, intravascular volume contraction, specifically a reduction in the red blood cell mass, may play an important role in the pathogenesis of hyperadrenergic state observed in a subset of diabetic patients and in the pathogenesis of hyperadrenergic postural hypotension in affected diabetic patients.

Acetoacetates↗

PubMed1975

The history of controlled hypotension.

As the physiology of deliberate hypotension has been unravelled, and as each new pharmacological agent has become available which either depresses or blocks peripheral vascular tone, depresses myocardial performance, or interferes with the conducting tissues within the myocardium, its possible incorporation into the armamentarium of the anaesthetist who offers induced hypotension has been considered. The result has been a sequence of variations in technique of characteristically recognizable vintage. No matter how the condition of induced hypotension is produced, there is usually vasodilatation, and the characteristic disturbance in physiology is of a loss of postural reactivity in the cardiovascular system. Important lessons have been learned concerning the management of shock states. Though it is difficult to evaluate the morbidity of deliberate induced hypotension, and terms such as "physiological trespass" have been used by its antagonists, it would appear that a well-considered and skilfully managed controlled hypotension is no more of a physiological trespass than anaesthesia, nor indeed than the trespass of the surgeon's knife itself.

Anesthesia↗

PubMed1979

Hypertension during anesthesia on discontinuation of sodium nitroprusside-induced hypotension.

The authors had observed that on intraoperative discontinuation of sodium nitroprusside being administered to induce hypotension, mean arterial pressure increased to above the pre-hypotension level. Twelve patients who recieved hypotensive anesthesia for surgical correction of cerebral aneurysms were studied to evaluate the role of the renin-angiotensin system in this phenomenon. In the awake state, mean arterial pressure was 100 +/- 2 torr and plasma renin activity 3.0 +/- 0.1 ng/ml/hr. Thirty minutes after the establishment of stable halothane-nitrous oxide anesthesia, mean arterial pressure decreased to 85 +/- 1 torr and plasma renin activity increased to 4.4 +/- 0.1 ng/ml/hr. No appreciable change in either occurred over the next two hours of operation. During sodium nitroprusside-induced hypotension, mean arterial pressure decreased to 49 +/- 2 torr and plasma renin activity increased to 15.2 +/- 0.2 ng/ml/hr. Thirty minutes after discontinuation of sodium nitroprusside administration, mean arterial pressure increased to 112 +/- 2 torr, which was not only higher than the prehypotension level, but also significantly higher than that recorded in the awake state. Plasma renin activity at that time was 10.9 +/- 0.1 ng/ml/hr. As the half-life of plasma renin is 15 min, the data suggest that the persistently increased plasma renin activity is probably responsible for the increase of arterial pressure following sodium nitroprusside-induced hypotension.

Adolescent↗

PubMed1975

Altered renin release and propranolol potentiation of vasodilatory drug hypotension.

Vasodilating antihypertensive drugs induce hypotension with reflex tachycardia, renin release, and fluid and electrolyte retention. Propranolol can impair this renin release. The studies described here were designed to determine the hemodynamic role of vasodilatory drug-induced renin release and inhibition thereof by propranolol in two animals models, the unanesthetized, normotensive and the unanesthetized, genetically hypertensive rat. In studies with normotensive rats, propranolol impaired renin release and tachycardia resulting from hydralazine and minoxidil and potentiated their hypotensive action. Two additional interventions against the renin-angiotensin system were used in evaluating the mechanism of this potentiation. One was removal of the renin source by nephrectomy, and the second was blockade of angiotensin's vasoconstrictor action using a selective angiotensin antagonist, saralasin (1-Sar-8-Ala-angiotensin II (previously known as P113)).. Both interventions potentiated vasocilatory drug hypotension, as did propranolol, but did not prevent reflex tachycardia. When combined with saralasin propranolol did not add to protentiation by this peptide. A similar pattern of blood pressure decrement and potentiation was seen in genetically hypertensive rats when propranolol or saralasin treatment preceded hydralazine. Propranolol was demonstrated to block hydralazine-induced increases in serum renin activity in genetically hypertensive rats. We conclude that hypotensive potentiation of vasocilating drugs by propranolol in these animal models is mediated to a large extent by impairment of renin release. Persistence of hypotensive tachycardia after nephrectomy and after saralasin in normotensive rats suggests the irrelevance of angiotensin's central nervous system stimulation to this cardiac effect. Clinical studies are underway to quantify the potential importance of this beneficial drug interaction in man.

Angiotensin II↗

PubMed1977

[The present state of hypotension (author's transl)].

The study was made of the recent literature on controlled hypotension and its place in modern anaesthetic practice. The effects of the different techniques and drugs are outlined in this paper. The results of investigation revealed that the circulation of heart, brain, liver, and kidneys is able to tolerate a wide range of deviation of blood pressure. Hypotension induced by high doses of halothane alone, which used to be considered as an adequate measure, has recently been shown to cause such serious side-effects that it can no longer be recommended. Halothane lowers blood pressure almost exclusively by means of a reduction of the contractility of the heart muscle. Ganglionic blocking agents alone should not be used either because of their depressing effect on the heart; moreover their hypotensive effects are hard to control. The sole exception is trimetaphan but it produces other severe side-effects such as liberation of histamine. On the other hand ganglionic blocking agents combined with halothane can be recommended. The combined administration of these drugs allow an easy control of hypotension and the side effects are minimal. Only sodium-nitroprusside meets all the requirements of a hypotensive drug. It operates selectively in a peripheral vasoplegic manner without effecting the cerebral centres. Regarding the heart, no side-effect is known apart from tachycardia; cardiac output is not altered. The metabolism of sodium-nitroprusside requires precaution in dosage, as degradation takes place via the toxic compounds of cyanide. Therefore liver disease and disturbances in vitamin B12 utilisation are regarded as contraindications for the use of nitroprusside. That is also the reason why a maximum allowable dose of 10-15 gamma/kg body weight and minute should not be exceeded. Prophylactic administration of vitamin B 12a (hydroxocobalamin) should be considered in every case when nitroprusside is used.

Cardiac Output↗

PubMed1979

[Influence of combined moderate arterial hypoxaemia and moderate hypovolaemic hypotension on cerebral blood flow and cerebral oxidative and energy metabolism in the dog (author's transl)].

The influence on total cerebral blood flow, cerebral metabolic rates for oxygen, carbon dioxide, glucose, lactate and pyruvate and on cerebral grey matter content of glucose, lactate and pyruvate and high energy phosphate compounds of combined moderate reduction in cerebral perfusion pressure (CPP) and moderate arterial hypoxaemia was studied. Individually arterial hypoxaemia and arterial hypotension of the same degree would neither impair autoregulation of cerebral blood flow nor cerebral oxygen availability. Four groups of 10 dogs each were studied under control conditions (group I), with reduction of CPP to 70 mm Hg (group II), with reduction of paO2 to 45 mm Hg (group III) or with a combination of these degrees of hypotension and hypoxaemia (group IV) after steady states of 30 min duration. Cbf was elevated by 40% in group III (p less than or equal to 0.01), CMRO2 was reduced significantly in group IV (p less than or equal to 0.01, CMR lactate was raised significantly in all three experimental groups (p less than or equal to 0.01). All other data were not significantly different from values in control animals. Cerebral tissue lactate content was elevated significantly in groups II to IV as compared to controls (less than or equal to 0.05); changes in cerebral tissue content of glucose and energy rich phosphate compounds were not statistically significant. From the seemingly normal cerebral blood flow in hypotensive-hypoxaemic dogs it is concluded that autoregulation of cerebral blood flow has become ineffective because of vasodilatation consequent upon arterial hypoxaemia. Reduction of CMRO2 in this group points to metabolic insufficiency and to relative cerebral hypoperfusion, but since changes in cerebral content of high energy phosphate compounds were not significant, severe tissue hypoxia may be excluded. The increase in cerebral tissue lactate content is attributable to increased glycolytic activity known from hypotensive and hypoxaemic states. The present investigation suggests that in patients with hypoxaemia and hypotension, brain function may be endangered by a similarly marked change of circulatory and metabolic parameters.

Animals↗

PubMed1979

Controlled hypotension and moderate haemodilution in major hip surgery.

This study presents a series of 38 patients in whom total hip replacement was performed by using a hypotensive anaesthetic technique with moderate haemodilution. 17 patients operated on during normotension without haemodilution served as controls. Halothane, d-tubocurarine and pentolinium tartrate were the agents used. During the operation circulation was monitored carefully. Hypotension with haemodilution decreased the amount of the transfused blood to 1/3, compared with the normotensive group. The bloodless field during the hypotension also shortened the duration of the operations. No complications attributable to the hypotensive technique occurred. The results suggest that the hypotensive anaesthetic technique with haemodilution reduces the need for blood transfusion in major surgery. However, only patients in good cardiovascular status are suitable for this technique, and careful monitoring of the circulation is mandatory during the anaesthesia.

Aged↗

PubMed1976

Hypotensive responses following oral adminstration of beta-adrenoceptor blocking drugs to the conscious cat.

On oral administration, the non-selective beta-adrenoceptor blocking drugs (+/-)-bufuralol, (-)-bufuralol, propanolol, oxprenolol, pindolol and alprenolol produced hypotensive responses in the conscious cat; (+)-bufuralol was without effect. The selective beta-adrenoceptor blocking drugs practolol and atenolol had no effect on blood pressure but tolamolol elicited a hypotensive response. All the drugs tested reduced the tachycardia due to intravenous isoprenaline in the conscious cat; however, not all doses of these drugs reduced blood pressure. (+)-Bufuralol was devoid to beta-adrenoceptive blocking activity. Only tolamolol reduced the pressor response to i.v. phenylephrine in the conscious cat, indicating that alpha-adrenoceptive blocking activity may contribute to its hypotensive action. The results suggest that beta-adrenoceptive blocking activity is necessary for the hypotensive responses of these drugs. However, for the different drugs, there was no correlation between peripheral beta-adrenoceptive blocking activity and hypotensive response.

Adrenergic alpha-Antagonists↗