Three balanced anesthetic techniques for neuroanesthesia: infusion of thiopental sodium with sufentanil or fentanyl compared with inhalation of isoflurane.

STUDY OBJECTIVE: To compare emergence from anesthesia and the hemodynamic and respiratory depressant effects of thiopental sodium infusion plus sufentanil or fentanyl with those of isoflurane as the primary component of a balanced technique for neuroanesthesia. DESIGN: Randomized, double-blind, prospective study. SETTING: University hospital and its affiliated Veterans Affairs Medical Center. PATIENTS: Thirty patients undergoing elective craniotomy for aneurysm or tumor. INTERVENTIONS: Thiopental with infusion of sufentanil 0.1 microgram/kg/hr, thiopental with infusion of fentanyl 1 microgram/kg/hr, or inhalation of 0.25% to 2% isoflurane as the major component of a balanced anesthesia technique that included nitrous oxide (N2O) and vecuronium (potency ratio of sufentanil to fentanyl, 10:1). MEASUREMENTS AND MAIN RESULTS: Intraoperative stress response (as indicated by intraoperative hypertension) was said to be the percentage of time the patient required administration of an antihypertensive drug, measuring from the first dose of thiopental to discontinuation of N2O at the end of the procedure, excluding any period of induced hypotension. Rapidity of emergence was measured by the number of minutes from discontinuation of N2O to first opening of the eyes on command. Adequacy of spontaneous ventilation was evaluated by determining partial pressure of arterial carbon dioxide 1, 2, and 3 hours after discontinuation of N2O. Extent of vasoactive drug administration for control of intraoperative hypertension (as determined by the clinicians caring for the patients) was described by minutes of vasodilator infusion and milligrams of propranolol or labetalol administered. The frequency of postoperative hypertension was defined as the number of patients in each group who required medication for postoperative hypertension. No significant differences in variables were found for thiopental/sufentanil, thiopental/fentanyl, or isoflurane when these drugs were used with N2O and vecuronium. CONCLUSIONS: Any one of these balanced anesthetic techniques appears appropriate for craniotomy.     

Plasma histamine and catecholamine levels during hypotension induced by morphine and compound 48/80

Histamine receptors are present in adrenergic terminals, and histamine is reported to inhibit release of the neurotransmitter norepinephrine (NE) at certain neuroeffector junctions. However, a physiological role for histamine in modifying adrenergic neurotransmission has not been established. To examine the interaction of elevated plasma histamine and catecholamine release, two compounds that release histamine, morphine (3 mg/kg), and compound 48/80 (0.5 mg/kg), were administered intravenously (i.v.). Plasma norepinephrine (NE) levels were used to monitor sympathetic nervous system activity, and plasma epinephrine (Epi) levels were used to monitor adrenal activity. Both morphine and compound 48/80 caused an immediate and marked increase in plasma histamine. Simultaneous with this increase, a marked decrease in mean arterial pressure occurred. Plasma NE levels increased in animals administered compound 48/80, but in morphine-treated animals, plasma NE levels did not change from pretreatment values. Plasma Epi levels increased in both groups, but the magnitude and duration of the responses differed. The results indicate that elevated plasma catecholamines can increase in response to histamine-induced hypotension but this effect can be suppressed by the central actions of morphine.     

Intracranial cavernoma. Surgical results of 47 cases

We report the surgical results in a series of 47 patients with cerebral cavernous malformation who had undergone surgery between 1973 and 1994, with a follow up ranging from 12 months to 24 years (mean: 4 years). They were divided in there groups according to their initial clinical presentation: epilepsy (31 cases), hemorrhage (11 cases) and neurological deficit (5 cases). Surgery consisted of cavernoma resection only (11 cases) or its extension to surrounding gliotic tissue (36 cases). Results are satisfactory: no surgical mortality, low morbidity (4 cases), no recurrent hemorrhage, seizures disappearance with anticonvulsant therapy stop (4 cases) or alleviation (20 cases). Only one patient died far from surgery (6 months) consequently to his initial bleeding, while all the others lead a normal active life. The therapeutic management, compared to the literature, pleads in favour of intentionally surgical attitude and gliotic tissue removal as often as reasonably possible.     

Monitoring of somatosensory evoked potentials during surgery for middle cerebral artery aneurysms

Somatosensory evoked potentials (SEPs) were monitored during 53 procedures for aneurysms of the middle cerebral artery (MCA). "Significant" changes were reported to the surgeon, who took corrective action when possible. Changes in the SEPs were categorized as follows: Type I, no change; Type II, significant change with complete return to baseline; Type III, significant change with incomplete return to baseline; Type IV, complete loss with no return; and Type V, no response at baseline. Only 1 of 37 patients with a Type I SEP had a new neurological deficit, and this was a patient who could not be examined for several days after surgery because he was in a pentobarbital coma. All 4 patients with Type III and IV changes had new postoperative neurological deficits. Perhaps of greater importance, 4 of 5 patients with Type II changes had no new deficit. These patients all had changes in SEPs that were completely reversible by clip adjustment (2), prompt removal of temporary clips (1), and inducing hypertension after aneurysm trapping (1). These cases may, therefore, represent instances in which SEP monitoring allowed the clinicians to prevent a neurological deficit. The MCA supplies the area of the somatosensory cortex that controls the hand. Median nerve SEPs are, therefore, a theoretically ideal monitor during surgery for MCA aneurysms. This study suggests that the results of MCA aneurysm surgery may be accurately predicted and improved with SEP monitoring.     

Preparation of GO/SiO2/PEA as a new solid base catalyst for the green synthesis of some spirooxindole derivatives

Efficient and green one pot multi component synthesis of some spirooxindole derivatives in the presence of graphene oxide functionalized with 2-(1-piperazinyl) ethylamine (GO/SiO₂/PEA) as a solid base catalyst was studied. GO/SiO₂/PEA has been obtained through a two step reaction and characterized by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), thermo gravimetric analysis (TGA), Raman spectroscopy and X-ray diffraction (XRD). Green reaction conditions, short reaction times, reusable catalyst and a high to excellent yield of products are some of the advantageous of the presented method.

Efficient and green one pot multi component synthesis of some spirooxindole derivatives in the presence of graphene oxide functionalized with 2-(1-piperazinyl) ethylamine (GO/SiO₂/PEA) as a solid base catalyst was studied.     

Effects of enflurane, isoflurane, and nitrous oxide on somatosensory evoked potentials during fentanyl anesthesia

The effects of nitrous oxide, enflurane, and isoflurane on cortical somatosensory evoked potentials (SEPs) were studied in 29 patients undergoing intracranial or spinal operations. Anesthesia was induced with fentanyl (25 micrograms/kg, iv) plus thiopental (0.5-1.0 mg/kg, iv). In one group of patients (n = 12), nitrous oxide (50%) was compared with enflurane (0.25-1.0%), and in another group (n = 12) nitrous oxide (50%) was compared with isoflurane (0.25-1.0%). In a third group of patients (n = 5) with preexisting neurologic deficits, nitrous oxide (50%) was compared with enflurane (0.25-1.0%). In all three groups, one gas was administered for 30 min, and then the alternate gas was administered for 30 min; then the cycle was repeated for a total of two administrations of each of the two anesthetics. SEPs were determined before and after induction of anesthesia and at the end of each 30-min study period. The latencies and amplitudes of the early cortical components of the upper- and lower-extremity SEP were examined. Induction of anesthesia resulted in increases of latency in both upper- and lower-extremity SEPs without any alteration of amplitude. Nitrous oxide, enflurane, and isoflurane each decreased the amplitude of the upper-extremity SEPs compared with the postinduction value. The amplitude of the upper-extremity SEPs was less during nitrous oxide than with either enflurane or isoflurane. Nitrous oxide decreased the amplitude of lower-extremity SEPs below postinduction value, while enflurane and isoflurane had no effect. Isoflurane and enflurane increased the latency of both upper- and lower-extremity SEPs slightly, while nitrous oxide had no effect.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prevalence of discordant elevations of state entropy and bispectral index in patients at amnestic sevoflurane concentrations: a historical cohort study

Background

Processed electroencephalogram (EEG) monitors help assess the hypnotic state during general anesthesia or sedation. Maintaining the bispectral index (BIS) or state entropy (SE) between 40 and 60 has been recommended to mitigate anesthesia awareness. Nonetheless, SEs > 70 were frequently observed at end-tidal sevoflurane concentrations unlikely to allow awareness. We sought to determine the prevalence of elevated discordant measurements during BIS and SE monitoring.

Methods

Electronic data collected over 11 months at two academic hospitals were retrospectively reviewed. At the hospital using SE, all cases were included with patients ≥ 18 yr and sevoflurane administered for at least 30 min during surgery. A cohort of cases propensity matched by age and American Society of Anesthesiologist Physical Status were selected from the hospital using BIS. Elevated discordant EEG indices were defined as values > 70 occurring during stable end-tidal sevoflurane concentrations > 1.5%. The odds ratio (OR) based on the probability of a case having at least one elevated discordant SE or BIS lasting ≥ two minutes (primary endpoint) was calculated.

Results

At each hospital, 3,690 cases were studied. The mean (95% confidence interval [CI]) incidence of cases with at least one interval of an elevated discordant EEG index lasting at least two minutes was 3.6% (2.8% to 4.4%) for SE compared with 0.24% (0.17% to 0.27%) for BIS (pooled OR, 17.0; 95% CI, 8.3 to 34.7; P < 0.001).

Conclusions

The prevalence of an elevated discordant EEG index is much greater with SE than with BIS. Elevated index values occurring at anesthetic concentrations well above the awareness threshold need to be assessed to determine if they indicate an inadequate depth of anesthesia requiring treatment or if they simply reflect the underlying monitoring algorithm.

     

Implementation of buffy‐coat‐derived pooled platelet concentrates for internal quality control of light transmission aggregometry: a proof of concept study

Essentials

• In platelet function testing, standardized internal controls (IQC) are not commercially provided.
• Platelet function testing was performed daily on aliquoted pooled platelet concentrates.
• Pooled platelet concentrates showed stability for control purposes from Monday to Friday.
• Pooled platelet concentrates provide the necessary steadiness to serve as IQC material.

     

N-terminal pro-brain natriuretic peptide identifies patients at high risk for adverse cardiac outcome after vascular surgery

BACKGROUND: Preoperative N-terminal pro-BNP (NT-proBNP) is independently associated with adverse cardiac outcome but does not anticipate the dynamic consequences of anesthesia and surgery. The authors hypothesized that a single postoperative NT-proBNP level provides additional prognostic information for in-hospital and late cardiac events. METHODS: Two hundred eighteen patients scheduled to undergo vascular surgery were enrolled and followed up for 24-30 months. Logistic regression and Cox proportional hazards model were performed to evaluate predictors of in-hospital and long-term cardiac outcome. The optimal discriminatory level of preoperative and postoperative NT-proBNP was determined by receiver operating characteristic analysis. RESULTS: During a median follow-up of 826 days, 44 patients (20%) experienced 51 cardiac events. Perioperatively, median NT-proBNP increased from 215 to 557 pg/ml (interquartile range, 83/457 to 221/1178 pg/ml; P<0.001). The optimum discriminate threshold for preoperative and postoperative NT-proBNP was 280 pg/ml (95% confidence interval, 123-400) and 860 pg/ml (95% confidence interval, 556-1,054), respectively. Adjusted for age, previous myocardial infarction, preoperative fibrinogen, creatinine, high-sensitivity C-reactive protein, type, duration, and surgical complications, only postoperative NT-proBNP remained significantly associated with in-hospital (adjusted hazard ratio, 19.8; 95% confidence interval, 3.4-115) and long-term cardiac outcome (adjusted hazard ratio, 4.88; 95% confidence interval, 2.43-9.81). CONCLUSION: A single postoperative NT-proBNP determination provides important additional prognostic information to preoperative levels and may support therapeutic decisions to prevent subsequent structural myocardial damage.