Vascular effects of general anesthesia are usually described by changes in vascular resistance, which assumes a linear pressure-flow relationship passing through the zero-flow zero-pressure point, and neglects the pulsatile properties of the circulation. We compared the systemic vascular effects of isoflurane versus propofol anesthesia by measurements of aortic pressure-flow relationships, ...

The rostral ventrolateral medulla (RVLM) is part of the vasomotor centre which controls the cardiovascular system and may therefore be critical to the genesis of postoperative hypertension. This area is probably a common site of termination of different inputs involved in the baroreflex. It contains at least two classes of ...

BACKGROUND: Three strategies were employed to better define the afferent site(s) at which desflurane initiates its neurocirculatory activation. METHODS: Young (aged 19-28 yr) healthy volunteers were employed in three separate studies. Monitoring included electrocardiography, radial artery blood pressure, and direct recordings of sympathetic outflow to skeletal muscle blood vessels by ...

BACKGROUND: Anaesthesia in patients with ischaemic heart disease may cause adverse haemodynamic reactions. This investigation compares the cardiovascular effects of equipotent concentrations of desflurane and isoflurane in 30 patients (ASA III) with coronary artery disease before surgical stimulation. METHODS: After standardised induction of anaesthesia with etomidate, fentanyl and pancuronium and ...

The purpose of this study was to compare and evaluate sedation with intravenous xylazine (1.1 mg/kg bodyweight [BW]) versus intravenous romifidine (100 micrograms/kg BW) followed by induction of anesthesia with intravenous diazepam (0.04 mg/kg BW) and ketamine (2.2 mg/kg BW). Twelve healthy horses were used in a blinded, randomized, cross-over ...

We investigated the effects of isoflurane on the rabbit cardiovascular system at several end-tidal concentrations. Furthermore, because isoflurane has been reported to produce tachycardia while reducing sympathetic nervous activity and baroreflex function, we evaluated whether the chronotropic effects of isoflurane could be due to a vagal withdrawal. ECG, mean arterial ...

PURPOSE: To investigate changes of cerebral arteriovenous oxygen content difference (AVDO2) induced by surgical incision and to determine carbon dioxide (CO2) reactivity of the cerebral circulation during sevoflurane and isoflurane anaesthesia. METHODS: Twenty-one ASA 1-2 patients undergoing elective surgery for supratentorial tumours were randomly allocated to receive either 1.3 MAC ...

The aim of the study was to compare three anaesthetic agents in patients with ejection fraction below 0.40 subjected to coronary revascularization surgery. Twenty five elective coronary surgical patients with ejection fraction below 0.40 were prospectively studied. Premedication was pethidine 1 mg/kg and induction was fentanyl 0.03 mg/kg and pancuronium ...

BACKGROUND: This study was designed to evaluate the effects of sevoflurane with and without nitrous oxide on human middle cerebral artery (MCA) flow velocity, cerebrovascular carbon dioxide reactivity, and autoregulation compared with the awake state using transcranial Doppler ultrasonography. METHODS: In 14 patients, the time-mean middle cerebral artery flow velocity ...

General or regional anesthesia may be used for lumbar laminectomy. To determine whether one method is superior, 122 patients were randomly assigned to receive either a standard general anesthetic (GA) or spinal anesthesia (SA) supplemented with intravenous (IV) propofol sedation. Data from the intraoperative period through hospital discharge were collected ...

The application of digital pressure above the injection site during interscalene block has been advocated to prevent cephalad spread of local anesthetic. In prior studies, radiographs taken immediately after interscalene injection of radiographic contrast have supported this concept. However, the clinical efficacy of digital pressure has not been previously tested. ...

We have compared exposure to isoflurane while using the laryngeal mask airway (LMA) during anaesthesia under positive pressure ventilation with exposure while using tracheal intubation. Trace concentrations of isoflurane were measured directly using a highly sensitive photoacoustic infrared spectrometer (Bruel and Kjaer 1302, Denmark) during general anaesthesia in 20 eye ...

BACKGROUND: This investigation examined the effects of desflurane and sevoflurane on quantitative indices of left ventricular afterload derived from aortic input impedance (Zin) interpreted using a three-element Windkessel model. METHODS: After Animal Care Committee approval, dogs (n = 8) were chronically instrumented for measurement of systemic hemodynamics including aortic blood ...

The efficacy of an epinephrine test dose during epidural and combined epidural-general anesthesia is unknown. Thirty-two patients were randomized to receive 2% lidocaine at either a high (25 mL) or low (12 mL) thoracic level of epidural anesthesia followed by general anesthesia with 1 minimum alveolar anesthetic concentration nitrous oxide ...

INTRODUCTION: This study aims to evaluate possible differences between the maximum, minimum, and mean value over each epoch, or the instantaneous value at the end of the interval, when recording physiological data at 1-minute intervals. METHODS: The mean arterial pressure (MAP), heart rate derived from the radial pulse (PULSE), end-tidal ...

Arterial blood pressure and heart rate changes after afferent somatic sensory nerve stimulation are termed the "somatosympathetic reflex" (SSR). Inhibition of the SSR may partially represent an antinociceptive action. This investigation examined the actions of the volatile anesthetic, desflurane, on the SSR evoked by peripheral nerve stimulation. Rats anesthetized with ...

BACKGROUND AND OBJECTIVES: The depressant activity on sympathetic tone of subarachnoid anesthetic block is well known. The aim of this study was to compare cardiovascular response to an incremental dose of subarachnoid anesthesia administered through a small-bore microcatheter with the response to single-dose spinal anesthesia. METHODS: The 26 ASA I ...

BACKGROUND: At low dose, the halogenated anesthetic agents halothane, isoflurane, and enflurane depress the ventilatory response to isocapnic hypoxia in humans. In the current study, the influence of subanesthetic desflurane (0.1 minimum alveolar concentration [MAC]) on the isocapnic hypoxic ventilatory response was assessed in healthy volunteers during normocapnia and hypercapnia. ...

The cardiopulmonary effects of desflurane at end tidal concentrations of 10.3, 12.9 and 15.5 per cent during either spontaneous or artificial ventilation were studied in five beagle dogs. Desflurane anaesthesia resulted in tachycardia and a decrease in arterial blood pressure which were not significantly related to the end tidal desflurane ...

OBJECTIVE: To determine the effects of IV administration of fluids on PCV, serum total protein and blood glucose concentrations, and systolic arterial pressure in healthy anesthetized dogs undergoing elective surgical procedures. DESIGN: Prospective, randomized controlled trial. ANIMALS: 70 clinically normal dogs. PROCEDURE: Dogs received i.v. administration of 0, 5, 10, ...

PURPOSE: To determine the effect of isoflurane on left ventricular diastolic function, as assessed by Doppler echocardiography. METHODS: Ten patients with normal cardiovascular function were enrolled. Doppler measurements of mitral inflow velocities, and pulmonary venous blood flow velocities were measured preoperatively (transthoracic echocardiography), and intraoperatively (transesophageal echocardiography) at isoflurane MAC ...

For the evaluation of the hemodynamic interaction between the natural heart and an assist device, a reversible pharmacological model based on the channel blocker Verapamil under hyperkalemia, was developed for deterioration of left ventricular function. Four calves weighing 70-90 kg underwent standard implantation for left atrioaortal assist (BioMedicus, BP-80), pump ...

In patients without significant cardiovascular disease, the hemodynamic effects of sevoflurane and isoflurane are similar; however, the hemodynamic effects of sevoflurane in patients with hypertension and ischemic heart disease are unknown. To examine the effects of sevoflurane in comparison to isoflurane in this high-risk population, 214 patients scheduled for elective ...

BACKGROUND: The inhalation of high concentrations of isoflurane has been reported to increase the heart rate and the concentration of serum catecholamines. Although the precise mechanisms for the sympathetic activation of isoflurane have yet to be clearly elucidated, they are considered to possibly originate from the stimulation of airway sensory ...

BACKGROUND: Rapid increases in the inspired concentration of desflurane have been associated with sympathetic activation, tachycardia, hypertension, and in select cases, myocardial ischemia. The current study examined the effects of the rate of change of the desflurane concentration on the sympathetic and hemodynamic responses to desflurane and sought to determine ...

BACKGROUND: Pharmacological control of blood pressure is usually indicated during aortic cross-clamping (AXC). The aim of this study was to analyze the modulation by isoflurane (ISO), sodium nitroprusside (SNP) and milrinone (MIL) of the systemic circulatory responses to a standardized infra-renal AXC. METHODS: Chloralose-anaesthetized pigs were exposed to AXC at ...

Although changes in pulmonary function in parturients are documented, little is known about effects of regional anesthesia on these changes. This study was undertaken to determine if two local anesthetics, often used for epidural anesthesia for cesarean delivery, have different effects on pulmonary function testing. Nineteen ASA physical status I ...

The effects of 1.0, 1.5, and 2.0 minimum alveolar concentration (MAC) of sevoflurane on hemodynamic, pulmonary and blood chemistry variables were measured during spontaneous and controlled ventilation in healthy horses. Sevoflurane was the only anesthetic drug administered to the horses. In a dose-dependent manner, sevoflurane significantly decreased (P < .05) ...

In many studies reporting an increase in cerebrospinal fluid pressure (CSFP) after opioid administration, concomitant decreases in mean arterial pressure (MAP) have been observed. Autoregulatory cerebral vasodilation may therefore have been a factor in the CSFP increases. We tested the hypothesis that increases in CSFP after bolus injection of opioids ...

This study was performed to determine the cardiovascular responses to isoflurane in euthyroid and hypothyroid dogs. Four healthy mixed-breed dogs were studied prior to thyroidectomy (PRE), 6 months after thyroidectomy (HYP), and after 2 months of oral supplementation with 1-thyroxine (SUP). Heart rate (HR), cardiac output (Q), stroke volume (SV), ...

OBJECTIVE: To evaluate the cardiopulmonary effects of 2 anesthetic planes of desflurane (DES) during spontaneous ventilation (SV) and controlled ventilation (CV) in cats. DESIGN: Repeated Latin square. ANIMALS: Eight healthy adult cats. PROCEDURE: Each cat received 1.3 times the minimum alveolar concentration (MAC) of DES and 1.7 MAC of DES ...

Because of its nonpungent odor and low blood-gas solubility coefficient, sevoflurane might be an ideal drug for single-breath inhaled induction of anesthesia. Fifty ASA grade I-III ambulatory surgical patients (18-76 yr old) received a single-breath induction with either 5.0% sevoflurane or 5.0% isoflurane (randomized) in a 1:1 N2O/O2 mixture. Anesthesia ...

OBJECTIVE: To study the effects of inhalation anesthetic agents on the response of horses to 3 hours of hypoxemia. DESIGN: Controlled crossover study. ANIMALS: Five healthy adult horses. PROCEDURE: Horses were anesthetized twice: once with halothane, and once with isoflurane in O2. Anesthetized horses were positioned in left lateral recumbency. ...

This study was designed to investigate the effect of intravenous lidocaine on the sympathetic activity after a rapid increase in desflurane concentration. Twenty ASA grade I and II patients, were allocated randomly to a control group (C) and a lidocaine group (L). After induction of anesthesia with intravenous propofol 2 ...

The purpose of the present study was to quantify the inhibitory effect of inhaled halothane and isoflurane on acute hypercapnia-induced responses of capacitance-regulating veins and related cardiovascular variables in response to sequential 40-s periods of 5%, 10%, 15%, and 20% inspired CO2 (FICO2). Measurements were made in normoxic alpha-chloralose-anesthetized rabbits ...

BACKGROUND: Hypoxic pulmonary vasoconstriction (HPV) is a homeostatic mechanism whereby gas exchange is improved through the diversion of blood flow away from poorly oxygenated regions of the lung. The effect of isoflurane anesthesia on HPV is unclear. Using a chronically instrumented canine model, it was hypothesized that isoflurane anesthesia would ...

OBJECTIVE: To determine whether hemodynamic responses of halothane-anesthetized horses undergoing surgical procedures depended on anesthetic induction protocols used, and to determine whether hemodynamic responses to surgical manipulation could be detected. DESIGN: Prospective experimental study without controls. ANIMALS: 36 clinically normal horses. PROCEDURE: Horses were allotted to 5 groups according to ...

The effects of halothane and isoflurane on ventricular intracellular action potentials recorded in situ in pentobarbital anesthetized rats were studied. Halothane (0.5, 1 and 2 vol.%) and isoflurane (0.75, 1.5 and 3 vol.%) did not have identical effects on rat epicardial action potentials recorded by floating microelectrodes. However, over the ...

This study examined induction and recovery times and respiratory and cardiovascular changes during induction and recovery in paediatric patients undergoing anaesthesia under spontaneous respiration induced with sevoflurane (S group, n = 10) and halothane (H group, n = 9) at 2.4 MAC. FET/FI increased more rapidly, the incidence of breath ...

BACKGROUND: Epidural anesthesia is sometimes initiated during general anesthesia, yet few data exist concerning efficacy of epinephrine-containing test doses. METHODS: Thirty-six patients were randomized to receive either 0.5 MAC isoflurane, 1 MAC isoflurane, or 0.5 MAC each (1 MAC total) of isoflurane and nitrous oxide. Each subject received intravenous saline ...

We examined scattered-light changes in a rostral ventral medullary surface (VMS) area from five goats after blood pressure challenges during waking and halothane anesthesia. Reflected 660-nm images were digitized at 1/s after baseline; intravenous saline; 5, 10, or 15 micrograms/kg phenylephrine administration; or sodium nitroprusside infusion sufficient to lower blood ...

MATERIALS AND METHODS: Cardiovascular effects of two local anesthetic agent solutions containing 2% lidocaine with 1:80,000 epinephrine (LE) and 3% prilocaine with 0.54 microgram/ml felypressine (PF) used separately and in combination were observed. We made 38 separate monitoring sessions (30 minutes each) with healthy voluntary dental students. Participants were monitored ...

OBJECTIVES: Despite its widespread use, little is known about sevoflurane's physiologic effects. The direct myocardial effects of sevoflurane were compared with both halothane and isoflurane. DESIGN: Administration of minimum alveolar concentration (MAC) fractions of anesthetic (0 to 3.0) was systematically varied to decrease the possibility of time-related effects on measured ...

The accuracy and stability of caffeine and halothane concentrations in liquid Krebs medium were examined. Caffeine-Krebs Ringer's solution in incremental concentrations from 0.25 to 10 mM (N = 8 for each concentration) was serially assayed over a three-year period. Storage was at 4 degrees C. For serial testing of halothane ...

The influence of desflurane (DES) and isoflurane (ISO) on the intestinal vasculature was investigated in normoventilated cats (n = 10) during basal chloralose anesthesia (control). We measured heart rate, mean arterial pressure (MAP), and intestinal blood flow (optical drop flowmetry). Intestinal vascular resistance (IVR) was derived. To avoid changes in ...

BACKGROUND AND OBJECTIVES: Although the majority of elective lumbar spine surgical procedures are performed under general anesthesia, successful use of spinal and epidural anesthesia has been reported. This study was designed to evaluate the influence of baricity on the performance of spinal anesthesia for lumbar spine surgery. METHODS: The study ...

BACKGROUND: Sevoflurane is a new inhalational anesthetic with desirable clinical properties. In some clinical situations, an understanding of the detailed cardiovascular properties of an anesthetic is important, so the authors evaluated the hemodynamic effects of sevoflurane in healthy volunteers not undergoing surgery. METHODS: Twenty-one subjects were randomized to receive sevoflurane, ...

More prolonged gynecological laparoscopic operations are being performed in recent years, and a steeper head-down position is required. The early reports of hemodynamic changes during gynecologic laparoscopy are conflicting, and the effects of anesthesia, head-down tilt and pneumoperitoneum have not been clearly separated. Invasive hemodynamic monitoring was carried out in ...

This study primarily examined the effect of three endtidal isoflurane concentrations (0.2, 1.0 and 1.4%) on the isocapnic hypoxic ventilatory response (HVR), as well as the hypercapnic ventilatory response (HCVR), in 18 women (ASA I) who were all in the follicular phase of their menstrual cycle. Capnography was used, together ...

The purpose of this study was to compare the haemodynamic effects and emergence times of anaesthesia with sevoflurane with those of isoflurane when the agents were administered with nitrous oxide to adult patients (ASA I and II) undergoing surgery of at least an hour in duration. Fifty patients were randomly ...