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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Experiences with the anaesthetic management of 248 patients undergoing total hip replacement are presented. Blood loss does not appear to be influenced by hypertension, the method of venting or the type of anaesthetic, with the exception of neurolept-analgesia. The importance of oxygen therapy in the treatment of the pulmonary embolic syndrome is stressed and the prevention of deep venous thrombosis is discussed. Mortality and morbidity figures are given.
Anaesthesia 1978 Sep
PMID:Clinical considerations in anaesthesia for hip arthroplasty. 71 19

Five cases of expulsive hemorrhage occurring over a period of one year were reviewed. Two cases occurred during a trabeculectomy procedure. There appear to be multiple factors playing a role in the etiology of expulsive hemorrhage. There was not a single common factor among these 5 cases, except for the conjectural presence of some kind of vascular disease. However, there were some important factors that may have played a role such as glaucoma, hypertension, vascular disease, and general anesthesia (and sudden decompression of the globe).
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PMID:Expulsive hemorrhage: report of five cases. 73 15

Acute effects of 6-hydroxydopamine (6-OHDA, 400--900 microgram kg-1 intracisternally, i.c.i.) consisted of bradycardia and hypertension, maximal 2--3 h after injection and preceded after some doses by a phase of hypotension. This pattern was obtained in completely conscious rabbits and after propanidid and sodium pentobarbitone anesthesia. After 600 microgram kg-1 i.c.i. 6-OHDA the peak rise in blood pressure (25 +/- 3.8 mm Hg) was due to a rise in peripheral resistance involving particularly renal and intestinal beds. Suprapontine mechanisms contributed to both hypertension and bradycardia. Giving pontine rabbits 6-OHDA elicited a short-latency fall in blood pressure, resembling the hypotensive phase in intact animals. Chronic effects 7 days after 600 microgram kg-1 included a rapid loss of 10% of body weight associated with reduction in food and water intake. To avoid secondary circulatory effects the rabbits were artificially fed, halving the weight loss. At 7 days blood pressure had fallen by 7.4 +/- 2.3 mm Hg probably owing to this residual weight loss. From experiments involving administration of phenotolamine and clonidine in intact rabbits and the responses of pontine animals it is likely that both descending and ascending catecholaminergic pathways have inhibitory effects on blood pressure, though some of the pathways may also be excitatory. Absence of specific chronic circulatory changes may be due to compensation through parallel pathways involving other transmitters.
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PMID:Cardiovascular and behavioral effects of intracisternal 6-hydroxydopamine in the rabbit. 73 62

Systolic blood pressure was measured weekly in conscious and in anesthetized female Sprague-Dawley (SD) and Wistar-Furth (W/Fu) rats following adrenal enucleation, unilateral nephrectomy, and the imposition of a high salt intake. SD rats quickly developed adrenal-regeneration hypertension (ARH) which progressed rapidly, and was identifiable in both the conscious and the anesthetized state. W/Fu rats slowly developed mild ARH, which, with a single exception, was identifiable only in conscious animals; the arterial pressures were within the normotensive range under anesthesia. The depressor effect of ether was also greater in adrenal-enucleated W/Fu than in similarly prepared SD rats, and in hypertensives than in normotensives. It is concluded that blood pressure measurements taken under anesthesia may not be representative of the true resting blood pressures: this is likely to be a particularly crucial problem in identifying early hypertension under circumstances and in rat strains highly susceptible to the depressor effects of ether.
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PMID:Blood pressure in conscious and anesthetized adrenal-enucleated Sprague-Dawley and Wistar-Furth rats. 74 20

Since sub-endocardial ischemia is the consequence of a discrepancy between the blood demand and supply of oxygen at this level, the study of the myocardial performance by the measurement of the endocardial viability ratio (E.V.R.) is both useful and possible during anesthesia. E.V.R. is the ratio between the oxygen supply and demand of the myocardium. It is equal to the diastolic pressure time index (D.P.T.I.) over the tension time index (T.T.I.). Measurements are made at different times, by means of the arterial pressure and the left atrial pressure, as well as with the Datascope-E.V.R. Computer. During gradual morphine administration (0.5-1-1.5 mg/kg) and if no major surgical stress occurs, E.V.R. remains excellent and stable (1.46 - 1.48 - 1.43). It deteriorates more or less (1.29 - 1.09) during tachycardia or hypertension. Within the hour following the end of extracorporeal circulation, E.V.R. significantly improves (1.04 - 1.06 - 1.09 - 1.23). Although E.V.R. measurement is easy during cardiac surgery, it is impossible to carry out in case of arrhythmia. While morphine anesthesia induces no variation in E.V.R., tachycardia or hypertension require the addition of therapeutic drug. Within one hour following the end of extra-corporeal circulation, E.V.R. measurement shows improved endocardial viability, although the hemodynamic parameters undergo no significant change.
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PMID:Measurement of endocardial viability ratio (E.V.R.) during anesthesia for cardiac surgery. 75 39

Intra-arterial injections of bradykinin into the hindlimb of the rabbit cause two types of cardiovascular reflex effects displayed in succession. The first-type effects appear early and are of inhibitory nature, being represented by systemic hypotension, contralateral hindlimb vasodilation and bradycardia; the second-type effects appear later and are excitatory in nature, consisting of hypertension, hindlimb vasoconstriction and tachycardia and occur closely associated with behavioral manifestations typical of the reaction to pain. Both the depressor and pressor effects are accompanied by hyperventilation. Analogous biphasic reflex responses may be caused by intraarterial injections of potassium ions. On the contrary, hypertonic solutions (NaCl, glucose) usually only produce second-type excitatory responses. No significant cardiocirculatory reflex effects are induced by even high doses of serotonin, nicotine, adenosine, adenosine triphosphate, adrenalin, noradrenalin, angiotensin, vasopressin and oxytocin. General anesthesia greatly inhibits the pressor reflexes and potentiates the depressor responses (to bradykinin and K ions) but does not appear to be a necessary condition for provoking depressor reflexes by chemical stimulation of somatic afferents. Both chemoreflex responses are prevented by sectioning the somatic nerves of the injected limb. Denervation of sinoaortic areas and of cardiopulmonary receptors by bilateral cervical vagotomy or complete removal of the skin from the injected limb does not prevent either type of chemoreflex response. These depressor and pressor chemoreflexes have been ascribed to activation of two functionally distinct types of sensory receptors in the skeletal muscle, differently sensitive to chemical substances and selectively concerned with different patterns of cardiocirculatory reflex response.
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PMID:Cardiovascular and respiratory chemoreflexes from the hindlimb sensory receptors evoked by intra-arterial injection of bradykinin and other chemical agents in the rabbit. 76 67

If the posterior hypothalamus contributes to elevate blood pressure in hypertension by increasing sympathetic vasomotor activity, then lesions of the posterior hypothalamus should lower blood pressure more in hypertensive than in normotensive rats. To test this hypothesis without complications caused by anaesthesia, aortic pressures were recorded from indwelling catheters in awake rats before and after selective hypothalamic destruction. In normotensive rats rats, bilateral lesions of the medial areas of the posterior hypothalamus always lowered blood pressure while those in the anterior hypothalamus slightly increased it. Heart rate responses varied widely and did not seem to contribute to the blood pressure changes. Posterior hypothalamic lesions of approximately the same size had significantly greater hypotensive after-effects in renal and spontaneously hypentensive rats than in normotensive or Doca hypentensive ones. These results imply that sympathetic overactivity emanating from posterior hypothalamic centres contributes to the blood pressure elevation in spontaneous or chronic renal hypentension but not in Doca hypertension. However, because of inherent weaknesses in the 'lesion method' and the complexity of blood pressure regulation in awake animals, other explanations are possible.
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PMID:Immediate hypotensive after-effects of posterior hypothalamic lesions in awake rats with spontaneous, renal, or Doca hypertension. 79 90

The cardiopulmonary effects resulting from the combination of xylazine and ketamine hydrochloride were evaluated in the adult horse. Xylazine (1.1 mg mg/kg) administered intravenously prior to or simultaneously with ketamine hydrochloride (2.2 mg/kg; intravenous) provided excellent analgesia and light anesthesia in all horses. Cardiac output, arterial blood pressure, pulmonary arterial pressure, central venous pressure, and pulmonary arterial wedge pressure remained within normal limits for the adult horse. Evidence of respiratory acidosis developed with time during the anesthetic period. Induction and recovery from anesthesia appeared smooth and excitement-free. In the horse, larger dosages of ketamine hydrochloride (6.6 mg/kg) following sedation with xylazine (1.1 mg/kg; intravenous) were accompanied by muscular tremor and rigidity, mydriasis, oculogyric movements, sweating, hypertension, tachycardia, and increased rectal temperature during recovery from anesthesia. Providing there is good sedation from xylazine, the combination of xylazine and ketamine hydrochloride as a short-term intravenous anesthetic technique in the horse appears safe and acceptable providing reasonably stable cardiopulmonary function. If the sedative properties of xylazine are not apparent or if excessive dosages of ketamine hydrochloride are used, the drug combination results in serious side effects precluding its use for anesthesia in the horse.
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PMID:Evaluation of xylazine and ketamine hydrochloride for anesthesia in horses. 84 17

A review of the anesthesia literature outlines safe limits for use of epinephrine with halothane anesthesia and adequate ventilation. Excluded from the safe category are patients with previous cardiac disease, hypertension, patients taking monoamine oxidase inhibitors and reserpine. Considered as safe is 10 milliliters of 1:100,000 epinephrine in 10 minutes and not more than 30 milliliters of 1:100,000 epinephrine per hour.
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PMID:Safe use of epinephrine with halothane anesthesia. 88 20

Because of the unresolved controversy regarding the effect of epidural anesthesia upon uterine contractility, it was decided to study its effect on a small number of patients. Intrauterine and intra-arterial continuous pressure, continuous fetal heart rate, and maternal heart rate recordings were obtained from at least 20 minutes before administration of the epidural anesthic until complete dilatation in these patients. Nineteen patients were in spontaneous labor, and 18 had labor stimulated with oxytocin. Plain lidocaine, 1 or 1.5%, was used in 12 patients (30 observations), and lidocaine with epinephrine, 1:200,000 was used in 26 patients (51 observations). Uterine contractions were calculated in Montevideo units for 60 minutes following the epidural anesthetic. The changes, if any, were compared in both groups. There was a significant decrease in uterine activity when epinephrine was added to the anesthetic solution, mainly a lessening of intensity. There were comparable decreases in systolic/diastolic blood pressure in both groups and compensatory tachycardia. In one case, severe hypertension was observed following administration of lidocaine epinephrine. It was concluded that the addition of epinephrine to the anesthetic solution predictably produces diminution of uterine activity, and it does not give "cardiovascular support" to the laboring patient.
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PMID:The effect of epidural anesthesia on uterine activity and blood pressure. 93 11


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