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

The purpose of this study was to assess the efficacy of sufentanil 1 micrograms.kg-1 during N2O-O2 and intermittent isoflurane anaesthesia in major non-cardiac surgery. Thirty-one patients (18 females, 13 males; mean age 47 yr), undergoing cholecystectomy received a 1 microgram.kg-1 bolus of sufentanil before the induction of anaesthesia with thiopentone. On average, three sufentanil increments were administered, to a total (bolus + maintenance) dose of 1.5 micrograms.kg-1. Cardiovascular stability was not achieved in eleven patients who then were given isoflurane. The arterial pressure decreased after sufentanil (P less than 0.05), reaching a nadir (mean 108/65 mmHg, heart rate 63 bpm) at one minute post-incision. Clinically important hypertension or hypotension did not occur in any patient. One patient, receiving beta-blocker therapy, required atropine to control bradycardia. Postoperative respiratory depression did not occur in patients who received less than one micrograms.kg-1.hr-1 with the last increment being given more than 20 minutes before the end of anaesthesia. Slight respiratory depression in the recovery room was reported in one patient, who had received a total of 1.3 micrograms.kg-1.hr-1 of sufentanil, and the last sufentanil increment 24 min before the end of surgery. The most frequently reported side-effects were nausea (35 per cent) and vomiting (23 per cent). Induction, maintenance and recovery from anaesthesia were rated as "good" in 87, 87, and 74 per cent of the cases, respectively, and "satisfactory" in the remainder. We conclude that this technique is valuable to assure good protection of the cardiovascular system without undue respiratory depression during recovery.
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PMID:Low-dose sufentanil in major surgery. 214 86

Traumatic brain injury affects systemic circulation as well as directly damages the brain. The present study examined the effects of fluid percussion brain injury on systemic hemodynamics and organ arterial blood flow in rats. Rats were prepared for fluid percussion injury under anesthesia. Twenty-four hours later, rats were anesthetized (1.0% halothane in N2O:O2) and prepared for radioactive microsphere measurement of cardiac output and organ blood flow. After baseline blood flow and physiological measurements were established, the rats were injured (2.47 +/- 0.02 atm, n = 17) or not injured (n = 20). Additional blood flow determinations were made at two of the following four time (T) points: 5, 15, 30, and 60 min after the injury or sham injury. Fluid percussion brain injury produced an immediate systemic hypertension followed by a hypotension and low cardiac output. Organ blood flows remained constant or increased for 30 min and then declined. Decreased blood flow was most pronounced in the kidneys and the spleen and was less severe in the liver. The reduced cardiac output was redistributed to favor blood flow through the heart and pancreas. These data suggest that traumatic brain injury creates a hyperdynamic period followed by a hypodynamic state with a heterogeneous hypoperfusion among organs.
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PMID:Traumatic brain injury creates biphasic systemic hemodynamic and organ blood flow responses in rats. 225 45

The effects of a moderate dose of sufentanil (1 microgram.kg-1 + 0.015 micrograms.kg-1.min-1) plus nitrous oxide (30% O2/70% N2O) anesthesia (group I; n = 8) and of high-dose sufentanil/O2 anesthesia (10 micrograms.kg-1 + 0.15 micrograms.kg-1.min-1) without N2O (group II; n = 8) on cardiovascular dynamics, myocardial blood flow, myocardial oxygen consumption, myocardial lactate balance, and hypoxanthine release were studied in two groups of male patients scheduled for elective coronary artery bypass surgery. All patients were on maintenance doses of calcium channel blockers and nitrates with the last doses of medications given the morning of operation. All patients were premedicated with flunitrazepam (2 mg orally), piritramide (7.5 mg IM) and promethazine (25 mg IM). Measurements were performed before the induction of anesthesia with the patients premedicated but awake; 20 min after induction of anesthesia with sufentanil plus pancuronium 0.1 mg.kg-1 for muscle relaxation before surgery; and during sternotomy and sternal spread. Sufentanil at either dose decreased mean arterial pressure, as well as cardiac and stroke volume index while heart rate remained unchanged. Following the induction myocardial blood flow and myocardial oxygen consumption decreased 23% (79 ml.min-1.100 g-1 to 61 ml.min-1.100 g-1 and 28% (9.2 ml O2.min-1.100 g-1 to 6.6 ml O2.min-1.100 g-1) in group I and 14% (78 ml.min-1.100 g-1 to 67 ml.min-1.100 g-1 and 18% (8.7 ml O2.min-1.100 g-1 to 7.1 ml O2.min-1.100 g-1) in group II. Myocardial ischemia was seen in one patient of group II (patient No. 4), as indicated by a hypoxanthine release into the coronary sinus, when after the induction MAP decreased from 93 to 67 mm Hg and heart rate increased from 56 to 71 min-1. During sternotomy 8 of 16 patients (50%) developed hypertension and 9 of 16 patients (56%) showed signs of myocardial ischemia, i.e., a lactate and hypoxanthine release.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Sufentanil does not block sympathetic responses to surgical stimuli in patients having coronary artery revascularization surgery. 252 78

Endotracheal intubation following anesthesia induction frequently produces hypertension and tachycardia. This study evaluated the efficacy of preinduction IV labetalol for attenuating the hemodynamic responses to intubation following thiopental and succinylcholine induction of anesthesia. Two hours after diazepam (10 mg by mouth), 60 patients were randomized in a double-blind manner and received IV saline or labetalol at doses of 0.25, 0.5, 0.75, or 1 mg/kg in a parallel design study. Five minutes later, thiopental (4 mg/kg) and succinylcholine (1 mg/kg) were administered, and the trachea was intubated in 2 minutes. Nitrous oxide (70%) anesthesia was maintained for 10 minutes. Hemodynamic parameters were grouped and analyzed for significance (p less than 0.05) by two-way repeated measures analysis of variance and t-test with Bonferroni adjustments. Baseline group demographics and hemodynamics were comparable. All doses of labetalol significantly attenuated the rate-pressure product increase immediately postintubation versus placebo. There was a dose-dependent attenuation of the increases in heart rate and the systolic, diastolic, and mean blood pressures versus placebo following intubation. IV labetalol at doses up to 0.75 mg/kg offers an effective pharmacologic means of attenuating preoperative hemodynamic responses to endotracheal intubation.
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PMID:Attenuation of the hemodynamic responses to endotracheal intubation with preinduction intravenous labetalol. 262 87

Twenty-five patients scheduled for lumbar fusion or cerebrovascular surgery were enrolled in an open label treatment controlled study comparing blood pressure and heart rate responses during deliberate hypotension with either esmolol or nitroprusside during steady-state N2O/isoflurane anesthesia. The first 5 patients were empirically assigned to the esmolol group; the remaining 20 patients were randomized to receive either esmolol or nitroprusside. The target of 15% reduction in mean arterial pressure (MAP) from baseline determined during anesthesia was attained with esmolol 195 +/- 10 micrograms/kg/min (mean +/- SEM) for the group (n = 15) or nitroprusside 1.9 +/- 0.3 micrograms/kg/min for the nitroprusside group (n = 10). Nitroprusside use was associated with a 15.9 +/- 5.3% increase in heart rate compared to a 12.1 +/- 2.2% decrease in the esmolol group (p = 0.0001 between groups). Upon termination of the hypotensive infusions, nitroprusside patients had a MAP increase of 13.9 +/- 5.5% above baseline (p less than 0.05 compared to prehypotension) while the 7.4 +/- 3.5% increase in the esmolol group was not statistically significant. Although 30% of nitroprusside patients overshot their baseline MAP by more than 25%, no esmolol patients had this degree of rebound. One esmolol patient had a brief period of atrial premature contractions. No patient in either group suffered any adverse reaction to hypotension. It is concluded that in moderate doses esmolol is a safe and effective hypotensive agent during isoflurane anesthesia, with no reflex tachycardia and no significant potential for rebound hypertension. A MAP reduction of 30% from preanesthesia baseline was readily obtained with this combination.
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PMID:A controlled trial of esmolol for the induction of deliberate hypotension. 290 83

The cardiovascular responses, speed of anesthetic induction, incidence of chest wall rigidity, need for anesthetic supplements (phentolamine, N2O, and nitroprusside) to control intraoperative hypertension, and speed of postoperative recovery were measured and compared in 44 patients undergoing aortic and mitral valvular replacement with fentanyl-O2 or sufentanil-O2 anesthesia. After a lorazepamatropine premedication and pancuronium pretreatment, fentanyl was administered intravenously at a rate of 400 micrograms/min and sufentanil at 200 micrograms/min until patients were unconscious; at this time they were given succinylcholine and their tracheas were intubated. After intubation, an amount of fentanyl or sufentanil equal to the dose producing unconsciousness was infused over the next 30 minutes, at which time the operation began. Additional fentanyl or sufentanil was given whenever systolic arterial blood pressure (SBP) increased more than 15% over preanesthetic values. When three successive supplemental doses of the narcotic failed to effectively decrease SBP, phentolamine was used to control pressure before and during bypass; after bypass, N2O (25% to 50%) or, if N2O was ineffective, nitroprusside was used. Average time of induction was 3.4 +/- 0.3 for fentanyl and 1.0 +/- 0.2 min (mean +/- SD) for sufentanil. Chest wall rigidity occurred in 36% of patients in both groups. Total doses of fentanyl and sufentanil required for the entire operation were 113 +/- 11 and 9.0 +/- 0.4 micrograms/kg (mean +/- SD), respectively. Heart rate, cardiac output, and mean right atrial pressure remained unchanged throughout the study in both groups. Mean arterial blood pressure (MBP) and SBP were significantly decreased during induction and after intubation in patients receiving sufentanil, but not fentanyl.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Comparison of sufentanil-oxygen and fentanyl-oxygen anesthesia for mitral and aortic valvular surgery. 298 Sep 54

Thirty patients (ASA physical status II-III) with a history of arterial hypertension, whose blood pressure (BP) control varied from normotension to moderate hypertension (diastolic BP less than 110 mmHg), scheduled for elective surgery under general anesthesia, were randomly assigned to two groups. Group 1 was premedicated 90-120 min prior to induction with diazepam 0.15 mg X kg-1 po; group 2, in addition, received clonidine 5 micrograms X kg-1 po. Anesthetic depth was assessed by on-line aperiodic analysis of the electroencephalogram. Following lidocaine 1 mg X kg-1 and fentanyl 2 micrograms X kg-1 (group 1 only), anesthesia was induced with thiopental 3-4 mg X kg-1 and vecuronium 0.1 mg X kg-1 was used to facilitate endotracheal intubation. Anesthesia was maintained with isoflurane in N2O/O2 and supplemented by fentanyl. In group 2, clonidine produced a rapid preoperative control of systolic and diastolic BP from 166 +/- 32/95 +/- 14 to 136 +/- 80 +/- 11 (P less than 0.01), was more effective in blunting the reflex tachycardia associated with laryngoscopy and endotracheal intubation than lidocaine-fentanyl pretreatment. It significantly reduced the intraoperative lability (coefficient of variation) of systolic (P less than 0.01) and diastolic BP and heart rate (HR) (P less than 0.05), and resulted in significantly slower HR during recovery (P less than 0.01). Anesthetic requirements for isoflurane were reduced 40% (P less than 0.01) in group 2; narcotic supplementation was also significantly reduced (P less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Anesthesia and hypertension: the effect of clonidine on perioperative hemodynamics and isoflurane requirements. 360 32

The effects of succinylcholine (1.5 mg X kg-1 IV) administered five minutes after a defasciculating dose of curare (0.05 mg X kg-1 IV), were compared with the effects of atracurium (0.5 mg X kg-1 IV) on intracranial pressure (ICP) in 13 cynomolgus monkeys with intracranial hypertension (ICP approximately 25 mmHg). Neither succinylcholine nor atracurium increased ICP during general anaesthesia with 60 per cent N2O/O2, 0.5-1 per cent halothane. During a rapid sequence induction and intubation with thiopentone 5 mg X kg-1 IV, ICP increased equally with intubation following both atracurium (25 +/- 1 to 32 +/- 2 mmHg) and succinylcholine (25 +/- 1 to 31 +/- 2 mmHg) (p less than 0.05). Intubation was also associated with significant increases in PaCO2, CVP and MAP. We conclude that in this primate model of intracranial hypertension, neither atracurium nor succinylcholine (when given following a defasciculating dose of curare) elevates ICP. In terms of the elevation of ICP associated with intubation, atracurium was found to offer no advantage over succinylcholine.
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PMID:Comparison of the effects of succinylcholine and atracurium on intracranial pressure in monkeys with intracranial hypertension. 375 39

The effect of monopolar electrical stimulation of the intermediate portion of the solitary nucleus (SOL) on brain circulation was investigated in 48 anesthetized (N2O), artificially ventilated Wistar rats. The cervical spinal cord and bilateral vago-sympathetic trunks were severed to eliminate any change in arterial blood pressure mediated by the autonomic nervous systems on stimulating the SOL. Blood pressure was kept within the physiological range by intravenous phenylephrine infusion. Current intensity of the stimulus was set at 60 +/- 4 microA (mean +/- S.E.; n = 9), which was equivalent to 2.5 times threshold for vasopressin-induced pressor response. A sufficient dose of vasopressin-antagonist given to each rat shortly before determination of cerebral blood flow, prevented vasopressin-induced hypertension from stimulating the medulla. Stimulation elicited an increase in regional blood flow (14C-iodoantipyrine technique) by 72%, and 39% on average in the frontal and occipital cortices, respectively, and 25% in the caudate-putamen (p less than 0.05; n = 12 in control, and 9 in the stimulation studies). It was found that observed results included little detectable contribution from current spread of the stimulus toward the adjacent structures (dorsal medullary reticular formation and cuneate fasciculus) surrounding the SOL and from retrograde activation of the cerebellar fastigial nucleus. Overall, the present study suggests that a certain vasomotor mechanism, which is activated upon excitation of the intermediate portion of the SOL, regulates the blood vessels of the brain as a vasodilator.
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PMID:An increase in cerebral blood flow elicited by electrical stimulation of the solitary nucleus in rats with cervical cordotomy and vagotomy. 402 Dec 24

Because controversy exists regarding continued use of the seated position for neurosurgical procedures, this prospective (1981-1983) and retrospective (1972-1981) analysis of 554 seated patients was done to establish the incidence and severity of venous air embolism (VAE) related to type of surgical procedure and anesthetic technique; to examine the impact of specific monitoring practices on detection, morbidity, and mortality; and to establish the incidence of other complications related to the seated position (hypotension, quadriplegia, and arterial air embolism (AAE)). The overall morbidity and mortality related to the seated position was 1% (2 VAE, 1 AAE, 2 hypotension, 1 myocardial infarction) and 0.9% (1 VAE, 1 AAE, 2 hypotension, 1 quadriplegia), respectively. There has been no mortality since 1975. N2O did not seem to increase the incidence or severity of VAE. The seated position is safe in experienced hands if appropriate surgical and anesthetic skills are exercised in patient selection and management. Caution is advised in patients with atherosclerotic cardiovascular disease, severe hypertension, cervical stenosis, and right to left intracardiac shunts.
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PMID:Anesthesia and surgery in the seated position: analysis of 554 cases. 406 24


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