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

This study was designed to evaluate effects of enalaprilat, an angiotensin-converting enzyme inhibitor, on hemodynamic and hormonal responses during surgery at endotracheal intubation, incision, and limb-tourniquet inflation. Thirty patients undergoing limb procedures with general anesthesia (N2O/narcotic technique) and a pneumatic tourniquet were randomized to receive either preoperative enalaprilat (1.25 mg intravenously [i.v.] 20 min prior to induction) or intraoperative enalaprilat (0.625 mg i.v. at the onset of tourniquet-associated hypertension), with appropriate placebo controls. Arterial blood pressure and heart rate increased significantly in response to intubation in the placebo group. Although there were no significant differences in catecholamine levels, plasma renin activity was significantly increased at postincision in the preoperative-enalaprilat group versus the placebo group. This suggests that activation of the renin-angiotensin system may play a key role in mediation of intraoperative hemodynamic responses to endotracheal intubation. With respect to tourniquet hypertension, preoperative or intraoperative treatment with enalaprilat reduced neither the pressor response to tourniquet inflation nor the amount of enflurane subsequently required to control arterial blood pressure. These findings suggest that this response is mediated by pain pathways, and may be treated more effectively with anesthesia/analgesia.
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PMID:Intraoperative hemodynamic, renin, and catecholamine responses after prophylactic and intraoperative administration of intravenous enalaprilat. 786 30

Tachycardia and hypertension may cause myocardial ischaemia in patients with coronary heart disease going through major surgery. Thoracic epidural analgesia (TEA) has been reported to be beneficial in this situation. The haemodynamic effects of TEA in aortocoronary bypass surgery were investigated in 30 male patients < 65 years old and with ejection fraction > 0.5. They were randomized into 3 groups: the high dose fentanyl (HF) group receiving high-dose fentanyl (55 micrograms.kg-1) anaesthesia, the HF+TEA group receiving the same fentanyl dose+TEA with 10 ml bupivacaine 5 mg.ml-1 followed by 4 ml every hour, and the low dose fentanyl (LF) + TEA group receiving low-dose fentanyl (15 micrograms.kg-1) anaesthesia+TEA. Haemodynamic parameters, the use of vasoactive and inotropic drugs and fluid balance were followed during the operation and for 20 h postoperatively. Before bypass the only significant difference between groups was a higher mean pulmonary arterial pressure in the HF+TEA group and a lower systemic vascular resistance (SVR) in the LF+TEA group, both compared to the HF group. 89% of epidural group patients needed small doses of ephedrine whereas more HF group patients were given nitroglycerine. During bypass SVR and mean arterial pressure (MAP) were significantly higher and pump flow lower in the HF group compared to the LF+TEA group. More ketanserin to HF group patients and methoxamine to epidural group patients were given. After bypass heart rate increased in all groups. Lower MAP 0.5 h after bypass and higher filling pressures in the early post bypass period in the epidural groups, most pronounced in the HF+TEA group, were noted.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Thoracic epidural analgesia in aortocoronary bypass surgery. I: Haemodynamic effects. 788 6

Much evidence suggests that the midbrain periaqueductal gray region (PAG) plays a pivotal role in mediating an animal's responses to threatening, stressful, or painful stimuli. Active defensive reactions, hypertension, tachycardia and tachypnea are coordinated by a longitudinally oriented column of cells, found lateral to the midbrain aqueduct, in the caudal two-thirds of the PAG. In contrast, microinjections of excitatory amino acid (EAA) made in the ventrolateral region of the PAG in anesthetized or isolated animals evoke hypotension, bradycardia, and behavioral arrest. The aim of the present study was to examine further the effects of activation of neurons in the ventrolateral PAG. By injecting into this region low doses (40 pmol) of kainic acid (KA), a long-acting EAA, it was possible to observe a freely moving rat's behavior in a social situation (i.e., paired with a weight-matched, untreated partner). Such injected rats become quiescent, i.e., there was a cessation of all ongoing spontaneous activity. These rats were also hyporeactive: the investigative approaches of the partner failed to evoke orientation, startle reactions, or vocalization. Electroencephalographic measurements indicated that the effects of injections of KA in the ventrolateral PAG were not secondary to seizure activity. In addition to the quiescence and hyporeactivity reported here, and the hypotension and bradycardia reported previously, the ventrolateral PAG is a part of the brain from which analgesia has been readily evoked by electrical stimulation, or microinjections of either EAA or morphine. As a reaction to "deep" or "inescapable" pain, chronic injury, or defeat, animals often reduce their somatomotor activity, become more solitary, and are generally much less responsive to their environment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Quiescence and hyporeactivity evoked by activation of cell bodies in the ventrolateral midbrain periaqueductal gray of the rat. 792 98

Raised intracranial pressure is the final common path to brain damage and brain death from a variety of intracranial conditions. Since the introduction of continuous monitoring of intracranial pressure into neurosurgical practice, much work has been undertaken which has advanced our knowledge of intracranial pressure and its management. The treatment of raised intracranial pressure should begin as soon as possible. The position of the head and neck should be checked to ensure that there is not an excessive degree of flexion or rotation. The airway should also be checked for obstruction and the patient observed to ensure that he is not making respiratory efforts against the respirator. The body temperature should not be above normal. Blood gases or other parameters of the adequacy of ventilation should be assessed and any abnormalities corrected. The sedation/analgesia regimen should be checked to ensure that it is sufficient and the patient is not experiencing pain. The serum sodium should be checked to ensure that hyponatraemia is not the cause of the intracranial hypertension. If intracranial hypertension persists despite the meticulous applications of these measures, then more specific therapy is required. This essentially reduces to a choice between osmotic agents, hypnotic drugs and drainage of cerebrospinal fluid.
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PMID:[Therapy for high intracranial pressure]. 804 76

One hundred thirty patients undergoing major thoracotomy between June 1991 and June 1992 at The Royal Brompton Hospital, London, were analyzed; renal impairment developed in 31 patients (24%). The mortality and morbidity was significantly greater for the renal impairment group. Six patients (19%) with renal impairment died after operation, in contrast to 0 of the 99 patients in whom renal impairment did not develop. The average length of hospital stay for the patients with renal impairment was 12 days compared with 8 days for the normal renal function group (p << 0.001). Five factors were highly significantly associated with renal impairment: a past history of renal impairment or diuretic intake, undergoing pneumonectomy, postoperative infection, and blood loss (p < 0.001). The most important of these appears to be postoperative infection or blood loss, as they also were associated with death (p = 0.01). Other factors less significantly associated with renal impairment included a past history of hypertension, ischemic heart disease, intraoperative gentamicin, and epidural analgesia (p < 0.01). This study emphasizes that thoracotomy must be considered carefully in patients with these predisposing factors, particularly if pneumonectomy is likely. Care must be taken in the use of aminoglycosides and epidural analgesia. Maintenance of renal blood flow by careful control of hemodynamic indices appears to be the most important intervention.
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PMID:Renal impairment after thoracotomy: incidence, risk factors, and significance. 806 56

The obstetrical population is prone to difficult or failed intubation. Control of the airway is complicated by several factors specific to obstetric anesthesia: time of apnea is short due to a reduced functional residual capacity and pregnancy-induced hypertension and obesity are relatively frequent; anesthetist's skill can also be mentioned. The best approach to this problem lies in its prevention, using epidural analgesia as soon as possible. Furthermore, the number of difficult intubations can be considerably reduced by a thorough pre-anesthetic examination. Each anesthetist must keep an algorithm in mind, should a difficult or failed intubation in obstetrical patient occur. Whichever method is used (ventilation through a facial mask or laryngeal mask, transtracheal oxygenation), the anesthetist must never forget that the first priority is always the safety of the mother.
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PMID:[Difficult intubation in obstetrics]. 807 9

Despite of a chronic volume overload the left ventricle function of pregnant women is preserved by both afterload reduction (arterial vasodilatation) and a facilitation of heart filling through an increase in peripheral venous tone. Fetal oxygenation results from an equilibrium between placental and umbilical blood flows. During regional anaesthesia the sympathetic blockade leads to a peripheral vasodilatation (mainly in the capacitive territories) which is the cause of arterial hypotension through a decrease in cardiac output. Placental flow may therefore be altered by the reduced perfusion pressure and/or a reflex or pharmacological vasoconstriction. Hypotension is an infrequent event during labor epidural analgesia. However the incidence of hypotension is higher during regional anaesthesia for cesarean section, up to 35% following intrathecal injection of local anaesthetic. Prevention of hypotension requires (i) release of aortocaval compression by gravid uterus (ii) volume preloading (15 min i.v. infusion of crystalloid, 20 ml.kg-1 with ephedrine, 15 mg if spinal anaesthesia is chosen), and (iii) limitation of plain local anaesthetic dosage (epinephrine, 1:200,000 with fentanyl, sufentanil or clonidine). Hypotension must be promptly reversed to avoid placental and umbilical flow alteration. Titrated doses of vasopressors are useful, either ephedrine or phenylephrine. Finally regional anaesthesia is beneficial for the mother and the fetus through a reduction in plasma catecholamines, provided that arterial pressure remains unchanged. Thus during pregnancy-induced hypertension (PIH) epidural analgesia leads to an improvement of the reduced placental blood flow. However PIH renders the women susceptible to sympathetic blockade and the fetus easily vulnerable to an additional stress factor like acute decrease in placental flow due to hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Maternal-fetal cardiovascular effect of spinal anesthesia]. 808 40

Nineteen women with cardiovascular disease underwent voluntary per-celioscopic sterilisation under local anesthesia at the La Rabta Maternity and Neonatology Centre, Tunis, Tunisia, between 1 July 1988 and 31 March 1989. There were 8 cases of hypertension, 1 of mitral insufficiency and 10 cases of surgically treated valve disease (6 cases of commissurotomy for mitral stenosis and 4 valve replacements). Mean parity of the women was 5 and mean age 35.4. Their educational level was low. Thirteen of them had never used contraception and 4 had had at least 2 therapeutic abortions. Local anesthesia with analgesia was well appreciated since 15 women remained calm and experienced no pain. The procedure involved minimal pneumoperitoneum and Trendelenburg. Recourse to minilaparotomy under general anesthesia was necessary in only one case. The authors stress the importance of counselling patients at the onset and of cooperation with cardiologists and anesthesiologists, and discuss peri-operative treatment protocols (anticoagulants, antibiotics) in particular.
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PMID:[Voluntary surgical sterilization by laparoscopy in cases of cardiovascular diseases. Prospective study of 19 cases]. 810 55

Relatively few clinically significant drug interactions with anaesthetics have been documented in the literature. The following should be stressed since these interactions are not readily predictable or are potentially fatal. Pethidine should never be administered to patients who have received monamine oxidase inhibiting drugs within the last fortnight, since a fatal hyperpyrexia and/or hypertension may result. Thiopentone induction seems to make the heart more susceptible to arrhythmias caused by adrenergic drugs, and may cause severe arterial hypotension in patients treated with diazoxide. Midazolam orally should possibly be avoided as premedication in patients treated with erythromycin since anaesthetic concentrations of midazolam may result. Patients for whom bupivacaine analgesia is planned could preferentially be premedicated with other drugs than diazepam, which causes the serum level of bupivacaine to increase. Bradycardia and hypotension not attributable to sympathetic blockade have been reported following bupivacaine extradurally in verapamil-treated patients. Sulfonamides and the ester group of local anaesthetics, such as prilocaine in combination, may result in severe methaemoglobinaemia in infants. Epinephrine added to local anaesthetics may cause local vasodilation if administered to patients concurrently being treated with cyclic antidepressants, and the combination imposes the risk of severe hypertension and arrhythmias.
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PMID:Drug interactions with intravenous and local anaesthetics. 814 Aug 67

Seventeen infants were treated with inhaled nitric oxide for critical pulmonary artery hypertension after operations for congenital heart defects. In all 17 patients conventional medical therapy consisting of hyperventilation, deep sedation/analgesia, and correction of metabolic acidosis had failed. All children were monitored with a transthoracic pulmonary artery catheter inserted at operation. Pulmonary artery hypertension was defined as an acute rise in pulmonary pressure associated with a decrease in oxygen arterial or venous saturation. After failure of conventional medical therapy, 20 ppm of inhaled nitric oxide was administered to the patient. In all patients the pulmonary pressures decreased (mean pulmonary arterial pressure decreased by -34% +/- 21%) without significant change in systemic arterial pressure, whereas the oxygen arterial saturation and oxygen venous saturation increased by 9.7% +/- 12% and 37% +/- 28%, respectively. Fifteen children were discharged from the intensive care unit at 10 +/- 6 days (range 3 to 26 days) and two died. This study demonstrates that inhaled nitric oxide exerts a selective pulmonary vasodilation without decreasing systemic arterial pressure in children with congenital heart disease. The increased values of mixed venous oxygen saturation and urinary output suggest that this selective lowering of pulmonary vascular resistance improved the overall hemodynamics. The potential toxic effects of nitric oxide and nitrogen dioxide necessitate careful consideration of the risks and benefits of inhaled nitric oxide therapy.
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PMID:Inhaled nitric oxide as a therapy for pulmonary hypertension after operations for congenital heart defects. 815 35


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