Xenon anaesthesia for patients undergoing off-pump coronary artery bypass graft surgery: a prospective randomized controlled pilot trial.

BACKGROUND: Off-pump coronary artery bypass (OPCAB) surgery carries a high risk for haemodynamic instability and perioperative organ injury. Favourable haemodynamic effects and organ-protective properties could render xenon an attractive anaesthetic for OPCAB surgery. The primary aim of this study was to assess whether xenon anaesthesia for OPCAB surgery is non-inferior to sevoflurane anaesthesia with regard to intraoperative vasopressor requirements. METHODS: Forty-two patients undergoing elective OPCAB surgery were enrolled in this prospective, single-blind, randomized controlled pilot trial. Patients were randomized to either xenon (50-60 vol%) or sevoflurane (1.1-1.4 vol%) anaesthesia. Primary outcome was intraoperative noradrenaline requirements necessary to achieve predefined haemodynamic goals. Secondary outcomes included safety variables such as the occurrence of adverse events (intraoperatively and during a 6-month follow-up after surgery) and the perioperative cardiorespiratory and inflammatory profile. RESULTS: Baseline and intraoperative data did not differ between groups. Xenon was non-inferior to sevoflurane, as xenon patients required significantly less noradrenaline intraoperatively to achieve the predefined haemodynamic goals {geometric mean 428 [95% confidence interval (CI) 312, 588] vs 1702 [1267, 2285] µg, P<0.0001}. No differences were found for safety. Significantly more sevoflurane patients developed postoperative delirium (POD) (hazard ratio 4.2, P=0.044). The average arterial pressure was lower in the sevoflurane group {median75 [interquartile range (IQR) 6] vs 72 [4] mmHg, P=0.002}. No differences were found for other haemodynamic parameters, the respiratory profile and the perioperative release of inflammatory cytokines, troponin T, serum protein S-100ß and erythropoietin. CONCLUSIONS: Compared with sevoflurane, xenon anaesthesia allows a significant reduction in vasopressor administration in OPCAB surgery. Moreover, xenon anaesthesia was associated with a lower risk for POD, a finding that has to be confirmed in larger studies. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov (NCT01757106) and EudraCT (2012-002316-12).

Training needs and qualifications of anaesthesiologists not exposed to ALS.

OBJECTIVES: To establish which needs exist for specific training in Advanced Cardiac Life Support (ALS) in anaesthesiology residents and interns not exposed to structured ALS courses. METHODS: 48 residents, and seven interns accepted for training in anaesthesiology, were tested in a spontaneous, blind, cross-sectional, prospective assessment using a recording manikin with validated scoring system, a questionnaire, and 35 multiple-choice questions. RESULTS: 65% admitted not having had any CPR training within the last 2 years. The answers were correct in 55 +/- 14% of the cases, increasing significantly with the length of training (P = 0.001). One-rescuer CPR skills were inadequate: only 13% (n = 7) of participants scored within acceptable limits when using the Berden Scoring system (Berden et al., Resuscitation 1992;13:31-41), which assigned weighted error points to BLS skills. No correlation with skill was noted with increased length of residency, confidence, ER or ICU experience, or participation in CPR-incidents. CONCLUSIONS: Anaesthesiology residents and interns were not able to demonstrate BLS skills properly even while in training and did not recognize this themselves. CPR-related knowledge is poor and increases only incidentally over the years of residency even though participants were frequently confronted with seminars and resuscitation situations, and see protocols daily. The use of multiple-choice questions and the Berden scoring system avoids difficulties in evaluating case-scenario type of tests. We suggest that trainees are motivated to take part in standardized, intensive, recognised ALS courses which emphasize BLS skills and require (re)certification.

EEG-assisted titration of propofol infusion during neuroanesthesia: effect of nitrous oxide.

Total intravenous anesthesia (TIVA) with propofol is an alternative to standard techniques for neuroanesthesia. The present study compared the hemodynamic and recovery profiles of 46 neurosurgical patients randomly assigned to one of three different anesthetic treatment groups. Group 1 was anesthetized with a TIVA technique in which propofol was titrated using an EEG-assisted quantification method. Group 2 received a similar propofol-based infusion technique in combination with nitrous oxide. Group 3 (control) received a standard anesthetic technique consisting of thiopental, nitrous oxide, fentanyl, and isoflurane. Significantly less propofol was required in group 2 than in group 1 (7.4 +/- 1.9 vs. 9.0 +/- 1.0 mg/kg/h, respectively). The propofol blood concentration at the first appearance of EEG burst suppression was also higher in group 1 compared to group 2 (5.8 +/- 1.1 vs. 4.8 +/- 0.8 microg/ml). However, 25% of the patients in group 2 were treated for hypotension after induction, compared to none in groups 1 and 3. Hypertensive episodes, on the other hand, were more frequent in groups 1 (43%) and 3 (31%) than in group 2 (12%). Time to awakening was significantly shorter in the control group (6 +/- 6 min) than in groups 1 (14 +/- 10 min) or 2 (12 +/- 16 min). In conclusion, titration of propofol to achieve a burst suppressive EEG pattern resulted in a slower emergence from anesthesia than a standard "balanced" technique. Use of nitrous oxide with propofol produced more hypotension during induction; however, its use improved hemodynamic stability during the maintenance period.

Responsiveness of the cerebral circulation to acute alterations in mean arterial pressure during the administration of propofol.

The responsiveness of the cerebral circulation to acute increases in mean arterial pressure was studied before and during the administration of propofol 3, 6, or 12 mg/kg/h in the anaesthetised baboon. Although mean arterial pressure increased significantly on each occasion, there were no significant changes in cerebral blood flow. This indicates that the physiological responsiveness of the cerebral circulation to alterations in mean arterial pressure was preserved during the administration of propofol in the concentrations studied.

Anesthesia for craniotomy: total intravenous anesthesia with propofol and alfentanil compared to anesthesia with thiopental sodium, isoflurane, fentanyl, and nitrous oxide.

STUDY OBJECTIVE: To compare a total intravenous (IV) anesthetic technique based on propofol and alfentanil with a commonly used anesthetic technique for craniotomy. DESIGN: Open-label, randomized, clinical study. SETTING: Neurosurgical clinic at a university hospital. PATIENTS: Forty patients, aged 18 to 55 years, scheduled for brain tumor surgery. INTERVENTIONS: In 20 patients, anesthesia was induced with fentanyl and thiopental sodium and maintained with fentanyl, dehydrobenzperidol, isoflurane, nitrous oxide (N2O), and a thiopental sodium infusion. Twenty patients were anesthetized with a propofol loading infusion followed by a maintenance infusion at a fixed rate. In addition, alfentanil was administered as a loading bolus, followed by a variable-rate infusion, with additional doses as necessary to maintain hemodynamic stability. MEASUREMENTS AND MAIN RESULTS: A decrease in blood pressure (BP) after induction with thiopental sodium was followed by a significant increase in BP and heart rate (HR) during intubation. BP and HR did not change during the propofol loading infusion. However, the administration of alfentanil was followed by a similar decrease in BP with a return to baseline values during the intubation period. Return of normal orientation (7 +/- 5 minutes vs 27 +/- 23 minutes) and concentration (12 +/- 12 minutes vs 35 +/- 37 minutes) was shorter and more predictable for the propofol-alfentanil-treated patients than for the thiopental sodium patients. Maintenance propofol concentration (nine patients) was between 3 +/- 0.69 micrograms/ml and 3.36 +/- 1.17 micrograms/ml, while the concentration at awakening was 1.09 microgram/ml. Alfentanil concentration at extubation (nine patients) was 79 +/- 34 ng/ml. CONCLUSION: A total IV anesthetic technique with propofol and alfentanil is a valuable alternative to a more commonly used technique based on thiopental sodium, N2O, fentanyl, and isoflurane.

Accidental epidural administration of a high dose of sufentanil.

Epidural sufentanil infusions are routinely used for post-operative analgesia after high-abdominal and thoracic surgery in our hospital. The erroneous administration of a bolus of 250 micrograms of sufentanil epidurally was followed by a 24 hour episode of deep analgesia and respiratory depression. The recovery from respiratory depression over a 27 hour period is described.

Anesthetic management of aortic trauma.

Most of the increasing number of ruptures of the thoracic aorta are caused by traffic accidents. Only a minority arrive sufficiently in time at the hospital to receive medical attention. The diagnosis is very difficult to make both on clinical and radiologic findings alone. An aortography is necessary when there is the slightest suspicion of aortic lesion. The lesions are mostly found in the isthmic region of the descending aorta. This and other localisations are easily explained when some specific anatomic, mechanical and congenital factors are considered. Surgical repair should be carried out in all cases as fast as possible. During repair attention must be directed toward the prevention of kidney and spinal cord injury and equally to prevent proximal hypertension and overload during clamping of the aorta.

Anesthesia for trauma.

Anesthesia of polytraumatized patients represents a considerable risk for them. The proper treatment of a polytraumatized patient comprises the rapid stabilisation of all his vital functions. At the same time, the attempt must be made to achieve a complete picture of all his injuries in order to be able to select a reliable and safe anesthetic procedure. Over and beyond this, a continuation of all intensive care measures, in particular the optimalization of blood volume, the maintenance of gas exchange, the support of the cardiac, and the balancing of the acid-base and electrolytes, is of the greatest importance for an effective treatment of the polytraumatized patient.

Pharmacokinetics of propofol during continuous infusion for pediatric anesthesia.

The blood concentrations of propofol have been examined during anesthesia by continuous infusion of 12 mg/hg/hr. A bolus dose of 3 mg/kg body weight propofol was used to induce anesthesia. The mean concentrations at apparent steady state were in the range of 4.3 to 5.6 micrograms/ml during the infusion. The mean total body clearance, derived from the apparent steady state concentrations in the blood, was 0.0394 litres/kg/minute. The mean propofol blood concentration at awakening was found to be 2.3 micrograms/ml.

The effect of sufentanil on intracranial pressure (ICP) in anesthetized dogs.

The use of sufentanil in neuroanesthesia has been questioned because of a potential increase in intracranial pressure (ICP) in dogs and humans. The effect of sufentanil administration on ICP was studied in 6 dogs with normal and elevated baseline ICP, anesthetized with nitrous oxide and an intravenous piritramide infusion. No significant change in ICP could be demonstrated over a 30 minute observation period after administration of 2 micrograms/kg of sufentanil. The results indicate that this dose of sufentanil does not increase ICP in moderately hyperventilated dogs under stable anesthetic conditions.

The effects of propofol on intracranial pressure and cerebral perfusion pressure in patients with brain tumors.

In 7 patients with a brain tumor and intracranial hypertension treated by ventriculosubcutaneous drainage, intracranial pressure and cerebral perfusion pressure were continuously monitored during induction of anesthesia with fentanyl 1.5 micrograms/kg, propofol 2.5 mg/kg and vecuronium 0.1 mg/kg. End-tidal pCO2 was kept constant by manual ventilation and arterial pCO2 was verified before induction and before and after intubation. Five minutes after induction the patients were intubated and measurements continued for five more minutes. Mean arterial pressure decreased from 102 (+/- 9.8) mmHg to 57 (+/- 11.6) mmHg (p less than 0.01). Intracranial pressure did not change significantly before intubation. However in two patients intracranial pressure increased before intubation due to a significant rise in arterial pCO2. In 4 of the 7 patients an important increase to 25 (+/- 4.6) mmHg in intracranial pressure was observed during intubation. Cerebral perfusion pressure decreased from 88 (+/- 4.6) to 45 (+/- 9.8) mmHg (p less than 0.01) before intubation, but did not differ from the baseline during and after intubation. It is concluded that propofol 2.5 mg/kg in a bolus injection does not increase ICP but can produce a significant decrease of the cerebral perfusion pressure due to a marked decrease in mean arterial pressure in patients with a brain tumor.

The value of carotid stump pressure and EEG monitoring in predicting carotid cross-clamping intolerance.

The authors analyse their experience with carotid stump pressure (CSP) and electro-encephalogram (EEG) monitoring in relation to the incidence of peroperative stroke during internal carotid artery reconstruction. A series of 215 patients is presented, among whom six (2.8%) developed a peroperative stroke. The stroke rate in patients with a CSP below 50 mm Hg (n = 92) was 7% (2/27) without a shunt and 3% (2/62) with the use of a shunt. The respective numbers for patients with a CSP equal to or above 50 mmHg were 1.7% (2/123) and 0% (0/10). The EEG remained normal after cross clamping in 180 cases (84%): the incidence of stroke was 1.5% (2/138) without and 5% (2/42) with a shunt. A shunt was used in 33 of the 35 patients with EEG changes after cross clamping. None of them sustained a stroke in contrast to both patients where despite EEG changes no shunt was used (respective stroke rates 0% and 100%). It is concluded that regarding cerebral function, EEG monitoring provides more accurate information than CSP.

[Anesthetics: total intravenous anesthesia or inhalation anesthesia in neurosurgery]. / Agents anesthésiques: anesthésie exclusivement intraveineuse ou anesthésie par inhalation en neurochirurgie.

In this review article the pro's and contra's of the use of either inhalational or intravenous anaesthetics for neurosurgical procedures are discussed. The objective is to stimulate thoughts concerning controversial subjects, rather than to resolve issues. It is much less complicated to approach the practice of neuroanaesthesia with a few straight forward "rules" based on laboratory measurements (such as intravenous drugs are good because they reduce CBF and ICP, whereas inhalational agents are bad because they increase CBF and ICP). It should also be noted that whereas statements about potential detrimental or beneficial effects of different anaesthetic agents are relatively common, there is a dearth of well-designed prospective studies of sufficient power to substantiate the outcome advantages or disadvantages. The choice of an anaesthetic should include more than just a consideration of the potential intracranial effects of a drug: it should also include experience with a drug and, more important a consideration of the patient as a whole.

Embolization of arteriovenous malformations of the brain: preliminary experience.

Transcatheter embolization was performed in 8 young patients (mean age 24.5 years) with intracerebral arteriovenous malformations. In total 12 arteries were embolized in 10 sessions. Clinical complaints of the patients included epilepsy in 4, sudden coma in 3 and severe sudden neurological deficit in 1. Intracerebral hemorrhage was documented in 4 patients and subarachnoid hemorrhage in 1. In all patients, prior to embolization a superselective Wada-test was performed under wake-up anesthesia. Embolization was performed with a mixture of acrylic glue and lipiodol. In one patient a detachable balloon was added. In 6 patients embolization of all the feeding arteries was possible, with total obliteration of the arteriovenous malformations in 4 and subtotal embolization (> 90%) in 2. In 2 patients reduction of the size of the arteriovenous malformation by one third was followed by total surgical removal of the lesion. In 1 patient reflux of the embolization material in the anterior choroidal artery caused severe neurological deficit with good clinical recuperation.

Influence of anesthesia on cerebral blood flow and cerebral metabolism: an overview.

Knowledge of the influence of anesthetics on cerebral blood flow and metabolism is the key to both safe neuroanesthesia practice and understanding the possible neuroprotection offered by these agents. In this paper the authors summarize recent data from the literature. All volatile anesthetics (except for nitrous oxide) produce a dose dependent decrease in cerebral metabolism. The changes in cerebral blood flow depend on the changes in cerebral metabolism and on direct vasodilatory effects; frequently volatile anesthetics increase cerebral blood flow. Cerebral autoregulation is dose-dependently altered. While CO2-response is preserved in the normal brain, this is not necessarily the case in injured brain or in presence of brain edema or tumor. Therefore, the volatile anesthetics are probably not the best choice when brain perfusion is impaired. Intravenous anesthetics (except ketamine) cause a dose-dependent decrease in cerebral metabolism and blood flow. Propofol has identical effects as the other intravenous agents. Autoregulation is preserved during the administration of propofol. The effects of narcotic agents depend largely on the background anesthetic. Pathological conditions induced physiologic changes, and coadministration of other drugs can greatly alter the effects of anesthetics on the brain.

Use of desflurane for outpatient anesthesia. A comparison with propofol and nitrous oxide.

Desflurane's induction and recovery characteristics were compared to those of propofol-nitrous oxide in outpatients undergoing laparoscopic procedures. Ninety-two healthy patients were randomized to receive either: 1) propofol induction and propofol-nitrous oxide maintenance (control), 2) propofol induction and desflurane-nitrous oxide maintenance, 3) desflurane-nitrous oxide, or 4) desflurane alone for induction and maintenance of anesthesia. Inhalation induction with desflurane-nitrous oxide was faster than with desflurane alone (100 +/- 35 vs. 124 +/- 43 s). Inhalation inductions were associated with a high incidence of apnea (17 and 26%), breath-holding (26 and 39%), and coughing (30 and 22%) in groups 3 and 4, respectively. The emergence time after discontinuation of desflurane in oxygen (4.5 +/- 2.1 min.) was significantly less than that after propofol-nitrous oxide (7.3 +/- 3.9 min.). However, times from arrival in the recovery room until the patients were judged fit for discharge were similar for all four treatment groups. Digit-symbol substitution test results and sedation visual analogue scores also were similar during the first 2 h in the recovery room. A lower incidence of moderate-to-severe nausea was reported in group 1 (15% vs. 52, 52, and 59% in groups 2, 3, and 4, respectively). In conclusion, induction of anesthesia with desflurane was rapid but is associated with a high incidence of airway irritation. Emergence and recovery profiles after maintenance of anesthesia with desflurane compared favorably to a propofol-nitrous oxide combination. However, propofol was associated with a lower incidence of nausea than was desflurane after outpatient anesthesia for laparoscopic surgery.

Efficacy of esmolol versus alfentanil as a supplement to propofol-nitrous oxide anesthesia.

In 97 outpatients undergoing ambulatory arthroscopic procedures, we compared esmolol with alfentanil when used to supplement propofol-N2O-atracurium anesthesia according to a randomized, double-blind protocol. After an initial intravenous dose of 16 micrograms/kg alfentanil, or 2 mg/kg of esmolol, a variable-rate infusion of alfentanil or esmolol was administered to maintain a stable heart rate. After induction of anesthesia with 2.5 mg/kg of propofol, mean arterial pressure decreased to a larger extent in the alfentanil-treated patients. Although heart rate and mean arterial pressure increased in both groups after tracheal intubation, alfentanil more effectively blunted the hemodynamic response to this stimulus. Maintenance of anesthesia was adequate in both treatment groups. After discontinuation of anesthesia, patients in the esmolol group opened their eyes earlier (7.2 +/- 2.4 min vs 9.8 +/- 4.6 min) than those in the alfentanil group. Esmolol-treated patients also reported less sedation in the first 15 min of recovery than those receiving alfentanil. However, there were no differences in times to ambulation and discharge between the groups. Esmolol-treated patients reported more postoperative pain for the first 15 min of recovery and more esmolol-treated patients required postoperative opioid analgesia than those treated with alfentanil. There were no significant differences in the incidences of nausea and vomiting between the two groups. The authors conclude that esmolol may be used in place of alfentanil to supplement propofol-N2O-atracurium anesthesia in outpatients undergoing arthroscopic procedures. However, hemodynamic responses to tracheal intubation were larger with esmolol, and avoidance of alfentanil did not decrease the incidence of postoperative nausea and vomiting in this outpatient population.

Blood pressure management during aortic surgery: urapidil compared to isosorbide dinitrate.

The efficacy and hemodynamic effects of urapidil, an arteriolar vasodilator, and isosorbide dinitrate, a venodilator, were compared, when used for blood pressure control during abdominal aortic surgery. Urapidil is an alpha-adrenergic receptor antagonist with serotonin-1A receptor-agonist activity in the central nervous system. Hemodynamic profiles were recorded before and after the administration of the study drug (+/- 10 minutes before aortic clamping), 3 and 10 minutes following aortic clamping, and before and 3 and 10 minutes following the removal of the aortic clamp. Arterial and mixed venous oxygen contents were compared. Both groups of 18 patients were similar with respect to demographic profiles, anesthetic technique, and perioperative fluid therapy. Identical heart rate and blood pressure profiles were obtained. In contrast to isosorbide dinitrate, urapidil produced a 17% (P < 0.05) increase in cardiac index as a result of a 30% (P < 0.001) decrease in systemic vascular resistance before placement of the aortic clamp. In patients treated with urapidil, cardiac index was higher (P < 0.05) 10 minutes after aortic clamping, before removal of the clamp, and 10 minutes later. The arterio-venous oxygen content difference decreased from 3.2 +/- 0.8 mL O2/dL to 2.4 +/- 1.0 mL O2/dL (P < 0.01) following urapidil, but did not change during the administration of isosorbide dinitrate. It is concluded that urapidil is an effective and safe drug for the prevention of the hemodynamic consequences of aortic clamping. Compared to a venodilator (isosorbide dinitrate), urapidil offers the advantage of improving cardiac output and oxygen delivery.

Propofol anesthesia does not inhibit stimulation of cortisol synthesis.

Recent data suggest a negative effect of propofol anesthesia on cortisol secretion. The present study was designed to evaluate the effect of propofol anesthesia on the steroidogenic potential of the adrenal glands. The response of cortisol secretion to stimulation with an adrenocorticotropic hormone (ACTH) analog during intravenous anesthesia with propofol has not been reported before. The response of the secretion of cortisol, 11-deoxycortisol, and 17 alpha-hydroxyprogesterone to tetracosactide stimulation was compared in patients anesthetized with propofol-nitrous oxide (n = 10) or thiopental-isoflurane-nitrous oxide (n = 10) and in normal volunteers (n = 10). The response to tetracosactide was similar in all three groups. An adequate increase in cortisol plasma concentration (more than 7.25 micrograms/dL) was obtained in all subjects except one volunteer. The increase in the plasma concentration of the cortisol precursors was also similar. We were unable to detect any influence of propofol anesthesia on the synthesis of cortisol in response to tetracosactide stimulation.

Vital organ blood flow during deliberate hypotension in dogs.

Increasing the inspiratory concentration of isoflurane is a commonly used technique for producing deliberate hypotension (DH) when isoflurane is used as the principal anesthetic. When an intravenous anesthetic technique is used, DH can be produced by the administration of a peripheral vasodilator, eventually in association with low concentrations of isoflurane. The aim of this investigation was to compare the effects of these two different approaches on vital organ blood flow. DH was induced in 12 mongrel dogs with two different anesthetic techniques: inhaled anesthesia with isoflurane (ISO) or an intravenous anesthetic technique combining propofol and alfentanil in combination with the alpha-adrenoreceptor antagonist, urapidil, and isoflurane at low end-expiratory concentrations. Mean arterial pressure (MAP) was initially decreased by 20% of its baseline and then to 50 mm Hg. Vital organ blood flows and the cerebral metabolic rate for oxygen were determined at each decrement in MAP, and after discontinuation of DH. A decrease in cardiac output was observed in the ISO group when MAP was decreased to 50 mm Hg. Cerebral blood flow was constantly and significantly higher in the ISO group. The cerebral metabolic rate for oxygen did not change compared to baseline values in both groups. At a MAP of 50 mm Hg, a decrease in renal blood flow was observed in both groups. Splanchnic blood flow remained stable in the intravenous anesthetic group in contrast to the ISO group where splanchnic blood flow decreased significantly.(ABSTRACT TRUNCATED AT 250 WORDS)