Variación del índice biespectral durante la técnica de Jannetta / Variation in the bispectral index during the Jannetta technique

No disponible

The perioperative combination of methadone and ketamine reduces post-operative opioid usage compared with methadone alone.

BACKGROUND: A synergy between ketamine and methadone (ME) to produce antinociception has been demonstrated in experimental neuropathy. We wanted to compare post-operative opioid requirements in patients undergoing multilevel lumbar arthrodesis after the administration combined ME-ketamine (MK) or ME alone. METHODS: This was a randomised double-blind study. During sevoflurane-remifentanil anaesthesia, 11 patients in each group received the following: ketamine bolus (0.5 mg/kg) after tracheal intubation, followed by an infusion of 2.5 µg/kg/min in the MK or saline bolus plus infusion in the ME group. Post-operative analgesia - during 48 h - was provided by patient-controlled analgesia (PCA), delivering bolus containing the following: ME 0.25 mg plus ketamine 0.5 mg in the MK group or ME 0.5 mg in the ME group. Lockout was 10 min, maximum of 3 boluses/h in both groups. Before closing the wound, all the patients received intravenous (i.v.) ME 0.1 mg/kg, dexketoprophen and paracetamol. Pain intensity was evaluated by a numerical rating scale (NRS), on arrival at recovery room (RR) and 24 and 48 h after surgery. In the RR, i.v. ME was administered until NRS was 3 when PCA was started. Dexketoprophen and paracetamol were administered 48 h. RESULTS: Remifentanil requirements were higher in the MK group (P = 0.004). Patients in the MK group received 70% less ME by PCA at 24 h (MK vs. ME group, median and interquartile range) - 3.43 mg (1.9-6.5) vs. 15 mg (9.65-17.38) (P < 0.001) - and at 48 h - 2 mg (0.5-3.63) vs. 9.5 mg (3.5-13.75) (P = 0.001). Patients in the MK group also attempted less doses, at 24 h: 19.5 (12.75-79.5) vs. 98 (41.5-137) (P = 0.043). Both groups had similar NRS values and comparable side effects. CONCLUSIONS: Perioperative ketamine-ME combination significantly decreased opioid consumption by PCA.

Implicaciones y actitud anestésica ante la utilización de 5-ala como marcador tumoral en la resección de gliomas malignos / No disponible

No disponible

Comparative assessment of the effects of alfentanil, esmolol or clonidine when used as adjuvants during induction of general anaesthesia.

BACKGROUND AND OBJECTIVE: This randomized, double-blinded, prospective study compared the effects of clonidine, esmolol or alfentanil on the level of hypnosis and haemodynamic responses to intravenous induction of anaesthesia and endotracheal intubation. METHODS: Forty-five patients scheduled for elective surgery were allotted to one of three groups. They were given either alfentanil 3 microg kg(-1) min(-1) (n = 15); esmolol 1 mg kg(-1) min(-1) (n = 16) or clonidine 3 microg kg(-1) (n = 14) as a 10 min infusion. The infusions of alfentanil and esmolol, but not of clonidine, were maintained during endotracheal intubation. Anaesthesia was induced with midazolam (2 mg) and thiopental as required to suppress the eyelash reflex. Atracurium (0.5 mg kg(-1)) was given to produce neuromuscular block. Mean arterial pressure, heart rate, and bispectral index were recorded on arrival (baseline), after study drug infusion, after injecting midazolam and thiopental, as well as after endotracheal intubation. ANOVA and chi2-test were used for analysis. RESULTS: Blood pressure, heart rate and the bispectral index were unaltered by the study drugs, but thiopental requirements were reduced by alfentanil and clonidine (P < 0.014). Mean arterial pressure values (mean +/- standard error of mean) in the alfentanil, esmolol and clonidine groups were: baseline: 107.8 +/- 3.8; 106.6 +/- 3.9; 103.4 +/- 3.7 mmHg; after thiopental: 74.0 +/- 4.2; 85.6 +/- 4.3; 94.2 +/- 4.1 mmHg and after endotracheal intubation: 91.7 +/- 5.3; 114.1 +/- 6.9; 123.6 +/- 5.6 mmHg, respectively (two-way ANOVA, P < 0.001). Mean arterial pressure changed significantly after intubation from baseline (P < 0.001) after alfentanil (-15%) and clonidine (+20%) but not after esmolol (+7%), while the changes between pre- and postintubation values were similar in all groups (24-33% increase). The bispectral index indicated that all patients had an adequate level of hypnosis, but the variability was higher in the esmolol group (P < 0.002). CONCLUSIONS: None of the study drugs blocked the increase in mean arterial pressure induced by endotracheal intubation, but esmolol provided better overall haemodynamic stability. All groups had an adequate level of hypnosis.

Awareness detected by auditory evoked potential monitoring.

We report a case of awareness detected by the Alaris AEP Monitor, a device that measures anaesthesia by tracking changes of the waveform of the mid-latency auditory evoked potential.

Simple method to determine the size of the laryngeal mask airway in children.

BACKGROUND AND OBJECTIVE: The size of the laryngeal mask airway in children is determined by the patient's weight. However, in some instances an alternative method may be wanted. The aim was to search for a new method that would be easy to perform at the bedside. METHODS: The size of the laryngeal mask airway was determined in 183 children by choosing the laryngeal mask that best matched the combined widths of the patient's index, middle and ring fingers. The results were compared with the standard method recommended by the manufacturer's weight-related guidelines. The patients were classified in different groups depending on the laryngeal mask airway sizes determined by both methods. A kappa coefficient evaluated the agreement between both techniques. RESULTS: The kappa coefficient was 0.81, showing an 'excellent agreement' between both methods. The size was the same for both methods in 142 children (78%). The disagreement between both techniques was only of one size in the remaining 41 patients (22%). In such patients, the weight was a borderline value that would indicate a change in the size of the laryngeal mask airway using the classic method. CONCLUSIONS: This new approach is of valid and practical use in children, particularly as an alternative in those situations where the patient's weight is unknown, such as in emergency situations or in those borderline instances where an alternative measurement would be useful.

Indice biespectral (BIS) y paro cardiaco / The bispectral index and cardiac arrest

No disponible

Effects of subarachnoid lidocaine, meperidine and fentanyl on somatosensory and motor evoked responses in awake humans.

Although the effects of local anaesthetics (LA) on motor and sensory transmission in the spinal cord have been described, the effects of opioids are controversial. Our aim was to evaluate the action of clinically relevant doses of subarachnoid (SA) meperidine (MP) and fentanyl (FN), on somatosensory (SSEP) and cortical motor evoked responses (CMER) in awake subjects. Thirty ASA I-II patients scheduled for infra umbilical surgery received SA (N = 10/group): 1 mg/kg lidocaine (LD), 1 mg/kg MP or 25 mu g FN. SSEP elicited by stimulation of the posterior tibial nerve at the ankle, and cortical motor evoked response at rest (r-CMER) and during facilitation (f-CMER) were obtained prior and 30 min after treatment. Conduction at the proximal segment of the motor nerve (F-wave) was evaluated by stimulation of the posterior tibial nerve at the popliteal fossa. Motor/sensory block and side effects were clinically assessed. LD completely abolished SSEP and CMER. At the same dose, MP abolished SSEP in 40% of the patients, while r-CMER and f-CMER were absent in 70% and 30%, respectively; in addition, the F-wave was absent in 50% of the patients. Fentanyl induced small changes in the latencies of SSEP and F-wave; however, a 28% decrease in the amplitude of the f-CMER (P<0.05) was observed. Pruritus was present in 60% of patients in the FN group (P<0.006). Our results show that while LD and MP block sensory and motor conduction at the spinal roots, FN seems to decrease the excitability of the spinal interneurons in the corticospinal tract.

[Etomidate perfusion in neurosurgery]. / Perfusión de etomidato en neurocirugía.

In this prospective study, 20 patients undergoing mean duration (2-3 h) neurosurgical operations on fossa cranii posterior, and cervical and dorsolumbar rachis, were induced with 0.3 mg/kg etomidate bolus dose. To maintain anesthesia, etomidate perfusions at 10 micrograms/kg/min (group I) and 20 microg/kg/min (group II) were administered. Fentanyl at fractionated doses was used as analgesic without association to nitrous oxide and relaxation was achieved with pancuronium bromide. Quality of hypnosis, changes in serum concentration of cortisol as well as hemodynamic and electrolyte changes were evaluated. Serum concentrations of cortisol, glucose, sodium and potassium were measured in basal state, and during perioperative and postoperative period. Hemodynamic status was monitored and side effects were recorded. Patients of group I presented signs of deficient hypnosis consisting of marked sympathetic response. When etomidate perfusion ceased, both groups presented serum concentrations of cortisol under the lower normal limit. Six hours after operation, mean serum concentration of cortisol in group 2 patients was significantly lower than in group I patients; in their samples, a dose-dependent recovery was detected. Serum glucose concentration increased during anesthesia and operation and serum electrolyte concentration remained within normal range during perioperative and postoperative periods. Our results demonstrate that a 20 micrograms/kg/min etomidate infusion is adequate to achieve neuroanesthesia when nitrous oxide administration is contraindicated.