THE EFFECTS OF PROPOFOL ANESTHESIA ON LOCAL CEREBRAL GLUCOSE-UTILIZATION IN THE RAT

The autoradiographic 14C-2-deoxy-D-glucose method was used to determine local cerebral glucose utilization (LCGU) during propofol anesthesia and recovery in 52 regions of the rat brain. Control rats intravenously received 5 ml.kg-1.h-1 of the egg-oil-glycerol emulsion that constitutes the vehicle for propofol. Anesthetized animals received an iv bolus of propofol (20 mg/kg) followed by continuous infusion of the anesthetic at 12.5, 25, or 50 mg.kg-1.h-1 for 1 h prior to injection of 14C-2-deoxy-D-glucose and for the following 45 min. In addition, a fifth group of animals were studied immediately after awakening from a 20 mg/kg bolus of propofol as indicated by the first reappearance of head lift. All rats were spontaneously breathing room air throughout the experimental procedure. The general pattern of the cerebral metabolic response to propofol anesthesia was a dose-related, widespread depression of LCGU. At the three infusion rates of propofol tested, overall mean LCGU was reduced by 33\%, 49\%, and 55\%, respectively, and significant decreases were observed in 60\%, 85\%, and 90\% of the regions assayed. These effects were rapidly reversible, since in the recovery group, LCGU returned to near control values in the majority of the brain areas. Although all of the anatomofunctional systems (sensorimotor, extrapyramidal, limbic, and reticular) were involved, forebrain structures showed a greater sensitivity to the depressant action of propofol than did hindbrain regions.(ABSTRACT TRUNCATED AT 250 WORDS

Influence of acupuncture on the postoperative complications following ketamine anesthesia. The importance of manual stimulation of point R and shen menn

The Authors have investigated the antihallucinogenic and sedative effects of auricular points R and shen menn during surgery under ketamine anesthesia. The results demonstrate that the insertion of the needle in point R is very efficient in reducing hallucinations of ketamine emergence, while the insertion of needle in auricular point shen menn causes only a brief period of sedation in the beginning of the emergence period. The acupunctural technique employed by the Authors has been shown to increase considerably approbation of ketamine anesthesia

Spatial mapping of SEP in comatose patients: improved outcome prediction by combined parietal N20 and frontal N30 analysis

The aim of this study is to evaluate whether SEP spatial mapping can improve outcome prediction in comparison to the conventional SEP recordings. Twenty patients comatose as a result of head injury or cerebral vascular disorders were submitted to 19-channel SEP mapping from median nerve stimulation. SEP recording were performed within the 4th hospital day in 18 cases and over one month from the insult in the remaining two. Nine patients (45%) showed a good recovery or a mild disability, 3 (15%) a severe disability and the rest (40%) died or remained in a vegetative state. Five patients (28%) had bilaterally normal SEP, 5 (28%) the absence of both parietal N20 and frontal N30, while the others (44%) had a dissociation N20/N30 (namely, preserved N20 with absent N30). The SEP mapping was significantly related to the outcome (P = 0.0087) and improved the outcome prediction in comparison to the conventional SEP recordings, allowing to check the presence of frontal N30: in patients with bilaterally present N20 the outcome appeared to depend upon the N30. SEP mapping proved to be a far superior prognostic indicator than the Glasgow Coma Scale. In 3 patients with midline shift on CT scan an abnormal spatial distribution of N20 was disclosed by SEP mapping. Our preliminary results suggest that SEP mapping may improve the assessment of comatose patients in comparison to the use of parietal derivations only

Auditory and somatosensory evoked potentials in brain-dead patients

The short latency evoked potentials, allowing to assess the brain stem's function, can supply useful information in the diagnosis of Brain Death (BD). 15 BD patients were submitted to the auditory brain stem response (ABR); in 7 cases somatosensory evoked potentials from the medial nerve (SEP) were also recorded. The ABR was absent in 11 cases (73.3%), while in 3 cases only the I wave was present (20%); in one case the low-voltage I-V waves were present. Regarding the SEP, in 3 cases (42.9%) only the N9-N13 and P9-P13 waves were present, while in another 3 cases (42.9%) a N13/P13 dissociation was observable. In the remaining case, which presented a still reproducible I-V interval, the SEP was normal, thus excluding the diagnosis of BD. The ABR and the SEP, which are not roughly influenced by general anaesthetics and sedatives, are thus helpful in diagnosing BD. The SEP seems able to supply useful information more frequently than the ABR, but their combined use can guarantee maximum security of excluding false positives