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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↗
PubMed1977

On the mechanism of central hypotensive action of clonidine.

The hypotensive effect of clonidine in anaesthetised (pentobarbitone) cat has been analysed with the help of pharmacological tools. Application of clonidine (0.1%) to the exposed ventral surface of medulla oblongata produced hypotension (28.6%) and bradycardia (18%). Similar application of glycine (5%) and GABA (10%) also lowered the blood pressure of cat by 20.3% and 29.3%, respectively. The hypotension as well as the bradycardia owing to clonidine were significantly (p less than 0.01) blocked by similar prior application of atropine methylnitrate (1%) and hemicholinium-3 (HC3, 1%), whereas HC3 pretreatment only insignificantly blocked the hypotension produced by glycine (p greater than 0.80) and GABA (p less than 0.70). Topical application of atropine (1%) also blocked (p less than 0.05) the hypotensive effect of clonidine. Intravenous administration of clonidine (50 microgram/kg) produced hypotension (34.6%) after an initial hypertensive response and bradycardia (38.8%). The hypotension was significantly (p less than 0.01) blocked by pretreatment of the cat with intracerebroventricular atropine (4 mg) or HC3 (0.5 mg). Topical application of atropine (1%) to the ventral surface of medulla also significantly (p less than 0.05) reduced the hypotension and bradycardia resulting from intravenous administration of clonidine. It is concluded that an intact cholinergic link in the brainstem is essential for the hypotensive effect of clonidine.

Acetylcholine↗
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↗
PubMed1977

Hemodynamic evaluation of hypotension during chronic hemodialysis.

Hypotensive episodes occur frequently during hemodialysis; they are often sudden and difficult to prevent despite careful clinical control. Their etiology was studied by investigating the hemodynamic response of five patients submitted to ultrafiltration during their three first dialyses. A Swan Ganz catheter was inserted and left in position for 5 days. Simultaneous determination of cardiac output, mean pulmonary artery (PAP) and capillary and systemic arterial pressures were recorded. 10 hypotensive episodes were observed. In 3 patients in whom the first hypotensive episode occurred 10 minutes after the start of dialysis, there was a significant drop in PAP, cardiac index and stroke index while heart rate and peripheral resistance remained unchanged. Paradoxical bradycardia was observed. In 4 patients hypotension was observed more than one hour after initiation of dialysis. Before the hypotensive episode there was moderate elevation of heart rate and peripheral resistance and an insignificant reduction in PAP. Cardiac index and stroke index were diminished. The decrease in MAP was only 2 mm Hg. Hypovolemia is the most important factor in hemodialysis-induced hypotension but other factors such as vagal stimulation, autonomic neuropathy and osmotic disequilibrium can interfere with blood pressure control and trigger hypotension. Methods of preventing hypotension during dialysis, including the infusion of low molecular weight dextran, are discussed.

Adult↗
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 &#x2265;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↗
PubMed1977

Canine systemic and cerebral effects of hypotension induced by hemorrhage, trimethaphan, halothane, or nitroprusside.

In 62 dogs, hypotension to a mean arterial pressure of either 40 or 50 torr (equivalent to a cerebral perfusion pressure of 30 or 40 torr, respectively) for one hour was induced by hemorrhage (oligemia), trimethaphan, halothane, or sodium nitroprusside. Before and during the period of hypotension, the following were measured: mean arterial blood pressure, cardiac output, whole-body O2 consumption, cerebral blood flow, cerebral O2 consumption, arterial blood gases, blood O2 content, and lactate, pyruvate, glucose, epinephrine, and norepinephrine concentrations. At the end of the period of hypotension, brain biopsies were taken for determination of adenosine triphosphate, phosphocreatine, lactate, and pyruvate concentrations. In an additional eight dogs following one hour of hypotension (at 40 torr) induced by one of the four techniques, the brains were perfused with carbon black, removed, and examined. In another ten dogs following hypotension (at 40 torr) induced with either halothane or trimethaphan, the animals were observed for three days and then killed for examination of the brain. Dogs maintained at a mean arterial pressure of 40 torr, despite differences in cerebral blood flow, demonstrated metabolic disturbances compatible with systemic and cerebral hypoxia. These were greatest in those dogs given nitroprusside in excess of 1.0 mg/kg, presumably due to cyanide toxicity. In dogs maintained at 50 torr, metabolic disturbances were minimal or absent in the halothane- and nitroprusside-treated dogs but were still apparent in the oligemic and trimethaphan-treated dogs. Carbon black infusions revealed no evidence of non-homogeneous flow. Three of the ten dogs observed for three days had persistent post-hypotension neurologic dysfunction. Two of these were given trimethaphan. The results suggest that the systemic and cerebral effects of halothane and nitroprusside (at doses less than 1.0 mg/kg) are similar and at a mean arterial pressure of 50 torr are of little consequence. By contrast, hypotension induced by trimethaphan or oligemia results in detectable metabolic alterations even at a pressure of 50 torr.

Adenosine Triphosphate↗
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

Autoregulation of cerebral blood flow during controlled hypotension in baboons.

The effect of graded, progressive hypotension on the autoregulation of cerebral blood flow was studied in anaesthetised baboons. Progressive hypotension was produced over a period of four to five hours, either by graded haemorrhage or by the administration of increasing concentrations of hypotensive drugs. During haemorrhagic hypotension autoregulation was maintained until the mean arterial pressure had decreased to 65% of its baseline value, below which cerebral blood flow was pressure passive. In those animals subjected to drug-induced hypotension, autoregulation persisted to lower levels of mean arterial pressure (35-40% of baseline). It is postulated that under conditions of haemorrhagic hypotension, constriction of the extraparenchymal cerebral vessels in response to sympathetic stimulation decreases the possible range of autoregulation in the anaesthetised baboon.

Animals↗
PubMed1976

Effects of transient hypotension on the structure and function of rat kidney.

The immediate effects of renal structure and function of 60 or 90 min of hypotension and the effects of one to four days of recovery were studied in the rat. An initial diuresis occurred during the first day after hypotension, followed by decreased urine volumes. Along with the diuresis, the animals secreted a hypo-osmolar urine for two days following hypotension, which returned to a normal concentration at three days. Twenty four hour urine sodium excretion was depressed during the first and second days after hypotension while potassium excretion was no different from that of control animals. The morphologic alterations of tissue fixed immediately following 60 and 90 min of hypotension were greatest in the pars recta of the proximal tubule but were also seen focally in the pars convoluta. The cellular changes included dilated endoplasmic reticulum clumped nuclear chromatin, swollen mitochondria with small flocculent densities, and the formation of multivesicular bodies. One day after the hypotension, death cell and necrosis were observed extensively in the pars recta. This study describes an experimental model for the study of the renal effects of hypovolemic shock in rats.

Animals↗
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↗
PubMed1976

Changes in CO2 responsiveness and in autoregulation of the cerebral circulation during and after halothane-induced hypotension.

CO2 responsiveness of the cerebral circulation has been measured in baboons before, during, and after halothane-induced hypotension. At a systolic blood pressure (BP) of 60 mmHg, C02 responsiveness was abolished, but was maintained at higher levels of BP. After hypotension, CO2 responsiveness returned to control values. Autoregulation to BP increases induced by intravenous noradrenaline was impaired when cerebral perfusion pressure during the hypotensive period had been below 30-40 mmHg. It is concluded that at levels of halothane-induced hypotension commonly employed clinically, CO2 responsiveness of the cerebral circulation may be absent. The return of CO2 responsiveness in the post-hypotensive phase argues in favour of controlled hyperventilation after neurosurgery which has involved induced hypotension.

Animals↗
PubMed1977

Postural hypotension: adrenergic responsivity and levodopa therapy.

Four subjects with orthostatic hypotension were given intravenous infusions of methoxamine and isoproterenol. Methoxamine caused an elevation in systolic blood pressure. Isoproterenol resulted in a fall in blood pressure in three of the subjects. The heart rate decreased with methoxamine, but increased with isoproterenol. The responsivity in orthostatic hypotension was compatible with denervation supersensitivity. These effects were compared with the responsivity to methoxamine and isoproterenol of five labile hypertensives. Two patients with severe orthostatic hypotension were treated with regimens including levodopa. Levodopa alone would further aggravate postural hypotension. But in one subject given levodopa, ephedrine, and fludrocortisone and in the other managed on levodopa, tranylcypromine, and fludrocortisone, symptomatic orthostatic hypotension was successfully eliminated. These results support the usefulness of levodopa, in combination with adrenergic agents, as a therapeutic measure for advanced forms of orthostatic hypotension.

Adrenergic Fibers↗
PubMed1976

Changes in local cerebral blood flow following profound systemic hypotension.

The authors studied local cerebral blood flow in monkeys rendered hypotensive by infusion of a ganglionic blocking agent. Application of the 14C-antipyrine method demonstrated that the blood flow: 1) normally varies reproducibly from one structure to another within the brain; 2) appears at its lowest level in all structures during the early minutes of a rapid-onset hypotension; 3) maintains the same general rank order of blood flow rate during hypotension as was present during normotension; and 4) returns to supranormal levels immediately following the rapid restoration of blood pressure. The values for local cerebral blood flow remain close-to-normal in some animals and diminish significantly in others during late recovery from hypotension. The close-to-normal values accompany uncomplicated recoveries while the diminished values appear in those animals which became neurologically depressed. Areas of the brain considered predisposed to hypotensive injury did not exhibit depressions in blood flow rate during hypotension more markedly than did other brain areas. The present results are interpreted as strong evidence against the "border zone" hypothesis.

Animals↗