Anaesthesia with desflurane-nitrous oxide in elderly patients. Comparison with isoflurane-nitrous oxide.

BACKGROUND: Desflurane is a new volatile anaesthetic, very little soluble. We wished to compare efficacy, safety, and emergence and recovers; profiles of desflurane-N2O versus isoflurane-N2O anaesthesia in elderly patients. EXPERIMENTAL DESIGN: single blind, prospective randomised study. SETTING: operating rooms of two major teaching hospitals affiliated with the University of Milan. PATIENTS: fifty-seven patients ASA physical status II or III, aged 65 or older, undergoing urological (non-endoscopic), orthopaedic or gynaecological (non-laparoscopic) surgery of at least one hour duration, were randomly assigned to receive general anaesthesia with either desflurane or isoflurane in 60% N2O- 40% O2, after standardised premedication and induction. MEASUREMENTS: vital signs, end-tidal agent, narcotic requirement, and adverse event appearance were monitored throughout the study. RESULTS: Twenty-eight patients received desflurane and 29 isoflurane. Demographics, anaesthesia duration and exposure, and intraoperative fentanyl requirement were comparable in the two groups. Immediate emergence from anaesthesia (time to extubation and hand grip on command) was faster in desflurane group, albeit not significantly (8.4 +/- 6.4 vs 11.0 +/- 6.5 min and 8.6 +/- 6.0 vs 11.8 +/- 6.0); on the contrary, early recovery (time to state the name and date of birth) was significantly shorter in patients receiving desflurane (11.1 +/- 6.2 vs 17.3 +/- 7.8 min and 13.1 +/- 6.0 vs 20.9 +/- 10.9 min). Only 24 patients (12 in desflurane and 12 in isoflurane group) did need postoperative fentanyl administration; among them, requirement was significantly higher in desflurane patients (3.4 +/- 1.1 vs 2.4 +/- 1.3 micrograms.kg-1. Total time in recovery room was not different between anaesthetics, as well as adverse event prevalence and severity. CONCLUSIONS: Early recovery in elderly patients is faster after desflurane than isoflurane anaesthesia; this might contribute to increased requirement of postoperative analgesia. Occurrence of adverse event is comparable between the two anaesthetics.

Critically ill patients: immunological evidence of inflammation in muscle biopsy.

AIM AND METHOD: To verify whether muscle necrosis in critically ill patients could be due to an inflammatory process, we tested muscle biopsies from five intensive care patients with different inflammation-specific immunocytochemical markers (antibodies anti-class I major histocompatibility complex products (class I MHCP or HLA I), membrane attack complex (MAC), T lymphocytes helper-inducer (CD4), cytotoxic (CD8) and pan-B-lymphocytes). RESULTS: In three patients muscle biopsy showed class I MHCP positivity on the surface membrane of several groups of fibres, mainly perifascicular, and scattered microvascular deposits of MAC. In the other two patients muscle biopsy did not show class I MHCP and MAC positivity. CONCLUSION: Our results suggest that inflammation may be a component of muscle damage in some critically ill patients.

[Respiratory failure caused by myopathy in severe sepsis]. / Insufficienza ventilatoria da miopatia in corso di sepsi severa.

OBJECTIVE: To describe a generalized myopathic disorder occurred in the convalescence phase of illness of a critically ill patient. SETTING: Neurological Intensive Care Unit. PATIENT: A 43-year-old man with acute leukoencephalopathy and severe sepsis complicated by sustained and prolonged cardiovascular, respiratory and renal failure. After 15 days of complete respiratory autonomy, the patient presented an acute ventilatory failure associated with generalized muscle weakness. Neither a relapse of sepsis nor neurological worsening were detected. MEASUREMENTS AND RESULTS: Electromyogram resulted in normal conduction velocity in both motor and sensitive nervous fibers. Muscular biopsy showed marked fiber size variability with several hypotrophic fibers type II fiber grouping, several areas of degeneration-necrosis with macrophage invasion, dishomogeneous oxidative enzymatic activity, no increase in glycogen or lipid content. CONCLUSIONS: These results excluded critical illness polyneuropathy and all the other known myopathies. Prolonged period of sepsis with multiple organ failure can result in a direct generalized myopathy. This possibility should be kept in mind while treating long term critically ill survivors.

[Body, muscle, and visceral nitrogen balance in catabolic patients. Modification with metabolic treatment]. / Bilancio azotato corporeo, muscolare e viscerale in pazienti catabolici. Modificazioni col trattamento metabolico.

In sixteen severely catabolic patients, two different nutritional treatments with the same nitrogen input (0.30 gN.kg-1.die-1) but with a different caloric support: 30 kcal.kg-1.die-1 foe group A and 15 kcal.kg-1.die-1 for group B were infused. Body nitrogen balance (BN), muscle nitrogen balance (BNm) and, calculated as a difference of the two, visceral nitrogen balance were measured in every patient on basal day and on the second day of total parenteral nutrition. Both nutritional treatment reduced the catabolic state in the same amount: this was confirmed by a less negative body BN and by the reduced excretion of 3-MEH and amino acidic catabolic markers. Otherwise in the other compartments the treatments showed different effects: the metabolic support was more reduced by treatment A than it was by B, supplying to visceral compartment a lower nitrogen amount: the nitrogen dismission from muscle compartment, available for visceral tissues, is greater with treatment B than with treatment A. In conclusion, even if both treatments show the same effect on body nitrogen balance, they penalize either one of the examined compartment or the other. To avoid this problem, the study and the use of tissue-specific nutrients are desiderable. Tissue-specific solutions may warrant the balance among body compartment without any further increase of the nitrogen rate.

[Onset time and duration of action of neuromuscular block induced by increasing doses of vecuronium bromide]. / Onset time e durata d'azione del blocco neuromuscolare indotto da dosi crescenti di bromuro di vecuronio.

The authors determined the onset time and the duration of action of neuromuscular blockade by a 100-150 micrograms.kg-1 vecuronium random administration in 30 ASA I and ASA II patients during urological surgery. Neuromuscular blockade was evaluated by the electromyographic response to stimulation of the ulnar nerve train of four. The time from vecuronium administration to complete abolition of twitch response (T1 = 0%) did not change significantly, in spite of 50% increased dose of neuromuscular relaxant. The duration of action of neuromuscular blockade, that is the time from T1 = 0% to T1 = 25%, increased from 38.2 +/- 7.5 min to 52.5 +/- 19.8 min by the increasing of neuromuscular relaxant dose (p < or = 0.018). Vecuronium increased doses did not shorten significantly the onset time.

[Changes in the plasma amino acid profile in critically ill patients during total parenteral therapy]. / Variazioni del profilo aminoacidico plasmatico in pazienti critici durante terapia parenterale totale.

The aim of this study was to evaluate the kinetics of arterial plasma amino acid profile during the first 48 h of clinical TPN in order to assess the time necessary to reach the steady-state condition during infusion. Each patient was treated with one of three different amino acid solutions yielding, in the same nitrogen intake, different intakes of individual amino acids. We found four different kinetics for the administered amino acids: an increase of plasma levels immediately after the start of the TPN with no variations during the steady period; the same trend with the steady-state obtained after 6-24 h of TPN infusion; no influence at all; a decrease of fasting plasma levels with the steady-state attained variably during the study period. Each given amino acid showed a different trend partly depending on the supply, suggesting that the steady-state was reached sooner for most amino acids, when the supply was larger. With lower intakes, plasma levels were unaffected or decreased. We conclude that in critically ill patients at least 24 h are needed to obtain stable arterial plasma amino acid concentration during TPN with adequate intakes of amino acid. Knowledge offers the possibility for a quick and accurate assessment of the adequacy of a given preparation (tailored for critically ill patients), it reduces the time span of the study and, as a consequence, the influence of varied metabolic conditions.

[Sedation with flunitrazepam and its antagonism with flumazenil in endoscopic urological procedures: our clinical experience]. / Sedazione con flunitrazepam e suo antagonismo con flumazenil nelle procedure urologiche endoscopiche: nostra esperienza clinica.

Patients, especially males, do not easily stand endoscopic urological diagnostic examinations. So flunitrazepam (0.01 mg/kg IV) has been used to insure a suitable sedation. At the end of such examination flumazenil, a selective benzodiazepine antagonist has been injected. The levels of sedation and orientation so obtained and the cardiorespiratory parameters have been collected during a one hour follow-up from the intravenous injection of the antagonist. This method presents minimal side effects (a marginal, but statistically significative, systolic arterial pressure reduction), a completely normal coordination of movements and awareness of space and time relationship at the end of the observation period. Therefore it is a very good solution for short time examinations giving the chance to safely and shortly dismiss the patient.

[Nephrectomy in pulmonary tuberculosis patients: an anesthesiological approach]. / Nefrectomia in tubercolosi polmonare: un approccio anestesiologico.

Authors report a case of renal cell carcinoma in a patient suffering from cavitary tuberculosis. Nephrectomy was carried out in epidural anaesthesia together with Propofol continuous infusion and maintaining the patient in spontaneous breathing. The epidural anaesthesia avoided the possible pulmonary complications due to Nitrous Oxide and artificial ventilation. The combination of epidural anaesthesia with Propofol infusion gave both a better operability and a higher therapeutic compliance. The indications to this anaesthesiological method are analysed and discussed herein.

[Kinetic study during amino acid infusion in catabolic patients. Comparison between two solutions]. / Studio cinetico durante infusione aminoacidica in pazienti catabolici. Confronto tra due soluzioni.

The equilibrium kinetic of two different amino acid solutions was investigated in ten catabolic patients (Parentamin, Pierrel; HBC, Baxter). Plasma amino acid pattern was determined on arterial samples before TPN and several times over 48 hours of TPN. Nitrogen balance was measured from 24 hours urine collection. Three different cinetic trends were found: a fast modification (diminution or increase), a slow adaptation, or no modification of plasmatic levels, however each amino acid reached a steady state plateau. The adequacy of the infusion of each amino acid was evaluated comparing its steady-state plasma level to the after lunch level in healthy man. This made possible to approximate metabolic needs of each of the infused amino acids and to identify the inadequacy of some metabolic pathways to synthetized non essential amino acids lacking in solutions. This made possible to identify amino acids infused in excess or in defect, and those infused in dose adapt to the metabolic needs of such patients.

[Effects of various caloric intakes on nitrogen metabolism of the body, the muscles and the viscera during total parenteral nutrition with aminoacidic solution enriched with branched-chain amino acids]. / Effetto del diverso apporto calorico sul metabolismo azotato corporeo, muscolare e viscerale durante NPT con soluzione aminoacidica arricchita in BCAA.

Nitrogen metabolism was studied in ten injured/septic patients by means of a two compartment model, differentiating muscle from non muscle (central) tissue. During fasting muscle tissue loses a consistent amount of aminoacids which is retained in part by central tissue, giving rise to a positive nitrogen balance, whilst three methyl histidine and body nitrogen output are elevated. Total parenteral nutrition (glucose 15 kcal kg-1 day-1, nitrogen 0.30 g kg-1 die-1) improved body nitrogen balance and three methyl histidine excretion, but did not affect significantly either muscle or central nitrogen balance. Increasing caloric support to 30 kcal kg-1 day-1 did not showed any further effect on body nitrogen balance and three methyl histidine, while it improved significantly vs basal muscle nitrogen balance, but did not affect central nitrogen balance.

Influence of some metal ions on oxidation of nadh and on formation of the superoxide anion radical (O(2)(-)), during enzymatic catalysis by E.C. 1.2.3.2 xanthine oxidase.

The inhibitory effect of selected metal ions [Ag(I), Hg(II), Cu(II), Cr(VI), V(V), Au(III), T1(I) and Zn(II)], on the xanthine oxidase (XOD) catalysis of xanthine oxidation, has been investigated with reference to the XOD catalysis of oxidation of NADH. Hg(II), Ag(I), Zn(II) and Au(III) act as inhibitors, T1(I) has no effect and Cu(II), Cr(VI) and V(V) act as activators. The formation of O(2)(-) during XOD catalysis of oxidation of either xanthine or NADH has also been studied. All the metal ions considered act as inhibitors with respect to O(2)(-) production when the reducing substrate is xanthine, but only a few of them when the substrate is NADH, the others showing no effect whatsoever whether or not they activate NADH oxidation in the course of the same reaction. Vanadium (V) has an anomalous effect: it inhibits xanthine oxidation but considerably increases NADH oxidation, and thus appears to modify the catalytic properties of the enzyme. This behaviour appears promising as the basis for a kinetic method for determination of V(V).