Desflurane-remifentanil-nitrous oxide anaesthesia for abdominal surgery: optimal concentrations and recovery features.

BACKGROUND: Intraoperative combinations of volatile and opioid agents are used to achieve unconsciousness, hypnotic sparing, haemodynamic stability and uneventful recovery. This study describes the influence of different remifentanil concentrations on these variables when combined with desflurane during abdominal surgery. METHODS: Sixty-one healthy adult patients were randomly allocated to one of five predefined remifentanil target concentrations (3, 5, 7, 10 or 15 ng ml(-1)). Anaesthesia was titrated to maintain mean blood pressure (MBP), heart rate (HR) and BIS trade mark within predetermined values by adjusting desflurane delivery. Postoperative analgesia using propacetamol and morphine was initiated 30-45 min before skin closure, and continued using morphine PCA. RESULTS: Desflurane requirements adjusted to both BIS and haemodynamics were not significantly modified by the remifentanil concentration (median Fet(DES) 2.7% before incision, 2.5% intraoperatively, and 2.2% during closure), resulting in a calculated drug consumption of 0.22-0.25 ml min(-1) (with 1.5 l min(-1) fresh gas flow). High remifentanil concentration decreased MBP and HR, and reduced the duration of tachycardia, but increased the duration of hypotension. The optimal balance was obtained with a remifentanil concentration of 5-7 ng ml(-1) for intubation, 3 ng ml(-1) until incision, 10 ng ml(-1) during intra-abdominal surgery and 5-7 ng ml(-1) during closure. Post-operative morphine requirements were not significantly modified by intraoperative remifentanil concentrations (median 30 mg/24 h, range [2-88]). CONCLUSION: Remifentanil target concentrations from 3 to 15 ng ml(-1) had little influence on desflurane requirements or postoperative morphine consumption, but markedly modified intraoperative haemodynamic stability, suggesting that the target concentration should closely follow the successive noxious stimulations.

Mechanisms of molecular manipulation with the scanning tunneling microscope at room temperature: chlorobenzene/si(111)-(7 x 7).

We report a systematic experimental investigation of the mechanism of desorption of chlorobenzene molecules from the Si(111)-(7 x 7) surface induced by the STM at room temperature. We measure the desorption probability as a function of both tunneling current and a wide range of sample bias voltages between -3 V and +4 V. The results exclude field desorption, thermally induced desorption, and mechanical tip-surface effects. They indicate that desorption is driven by the population of negative (or positive) ion resonances of the chemisorbed molecule by the tunneling electrons (or holes). Density functional calculations suggest that these resonant states are associated with the pi orbitals of the benzene ring.

[Improvement in the control of chemotherapy induced emesis with ondansetron, methylprednisolone and lorazepam combination in patients treated by a moderate emetic treatment and uncontrolled by a previous antiemetic combination]. / Amélioation du contrôle des nausées et vomissements lors d'une chimithérapie modérément émétisnate, par l'association ondansétron méthylprednisolone et lorazépam, antiémétique antérieure.

The objective of this double blind parallel-group multicentre study was to compare the efficacy and safety of the combination ondansetron + methylprednisolone + lorazepam (O + M + L) in the prevention of emesis induced by chemotherapy with cyclophosphamide or adriamycin . This tritherapy was compared to a bitherapy O + M. Patients included were suffering from severe haemopathy or breast cancer. They had to have an incomplete response to a previous antiemetic association of 5HT3 serotoninergic receptor antagonist and corticoid. One hundred and thirty-five adult patients were included and were randomised to receive : O + M + L or O + M for 3 days. The emesis control during the 3 days of treatment (no emetic episode during the complete course) was significantly superior in the group O + M + L than in the group O + M (69% versus 46%, p = 0. 042); nausea control on the worst day of the cure was significantly superior in the group O + M + L than in the group O + M (p = 0.04) with 76% of patients in the group O + M + L having complete or major nausea control compared to 51% in the group O + M. The stability of quality of life during the days following chemotherapy measured by one questionnaire, including two scales, one cancer specific (FLIC) and one emesis specific (FLIE), appeared significantly better in group O + M + L (p = 0.04 and p = 0.019). Safety of both antiemetic regimens was good and similar between the two treatment groups. This trial shows that the adjunction of lorazepam to ondansetron and corticoid in combination increases the antiemetic control for patients with an incomplete response to a previous regimen containing a 5HT3 serotoninergic receptor antagonist and a corticosteroid in the prevention of chemotherapy-induced emesis.

The efficacy of a combination of ondansetron, methylprednisolone and metopimazine in patients previously uncontrolled with a dual antiemetic treatment in cisplatin-based chemotherapy. The French Ondansetron Study Group.

BACKGROUND: Cisplatin is one of the most effective cytotoxic drugs used in the treatment of certain neoplasms, but is also one which most frequently induces nausea and vomiting. Combination of corticosteroids with ondansetron enables greater control of emesis than that obtained with ondansetron alone, but some patients still experience symptoms. The objective of this randomised, double-blind, multicentre, parallel group study was to examine the benefit of the addition of metopimazine (MPZ), a dopamine receptor antagonist, to the combination of ondansetron + methylprednisolone (O + M) in the prevention of cisplatin-induced nausea and vomiting in patients uncontrolled [i.e., at least one emetic episode (vomiting and/or retching) or moderate or severe nausea] during their previous course of cisplatin based chemotherapy, despite antiemetic treatment with a combination of a 5-hydroxytryptamine3 receptor antagonist (5HT3) with a corticosteroid. The impact of the treatment on the patients' quality of life was also evaluated using two specific questionnaires the FLIC (Functional Living Index for Cancer), and the FLIE (Functional Living Index for Emesis). PATIENTS AND METHODS: The intent-to-treat population consisted of 338 patients; 168 patients received the triple combination of ondansetron, methylprednisolone and metopimazine (O + M + MPZ), and 170 patients received ondansetron plus methylprednisolone (O + M). Tumour type was comparable in the two treatment groups, the most prevalent being lung cancer. Patients in group O + M + MPZ received ondansetron as an 8 mg intravenous injection prior to chemotherapy on day 1 followed by 8 mg tablets b.i.d. from D2 to D3, methylprednisolone as a 120 mg intravenous injection prior to chemotherapy on D1 and followed by 16 mg tablets b.i.d. from D2 to D3, and metopimazine as a 40 mg intravenous injection prior to chemotherapy on D1 and followed by 15 mg capsules b.i.d. on D2 to D3. Patients in group O + M received treatment with ondansetron and methylprednisolone as above. RESULTS: Analysis of the primary efficacy criterion (absence of emetic episode throughout the course of chemotherapy) revealed a success rate of 53% in the group receiving O + M + MPZ and 38% in the group receiving O + M (P = 0.008). Analysis of the secondary efficacy criteria (nausea grade, number of emetic episodes and global patient satisfaction on D1 and from D2 to D3) showed a statistically significant difference between the two groups, in favour of the O + M + MPZ treatment. The scores obtained with the FLIC and FLIE questionnaires did not reveal any significant differences between the two groups. Treatment was well tolerated in both groups. CONCLUSION: The study showed that the addition of MPZ to the combination O + M was an effective and well tolerated antiemetic treatment, with a 15% increase in efficacy compared to the combination in patients not controlled during their previous course of chemotherapy. The addition of metopimazine to existing regimens containing 5HT3 receptor antagonist and steroid combination should be considered for patients who fail on their previous course.

[Proposal for a new descriptive psycho-physiopathological model of schizophrenia]. / Proposition d'un nouveau modèle descriptif psycho-physio-pathologique des schizophrénies.

We present the conclusions of a study of pattern recognition in an intermittent luminous stimulation. This stimulation was stable on the one hand and on the other hand on fixed time basis (S.L.I. pulsations emitted by two flickers) and other associated tests (reaction time, Rorschach Test, etc). We have compared a population of 30 schizophrenics (French classification) and a reference group of 53 adult subjects of both sexes. We have not divided the patients into subclasses according to their symptoms. We have noticed in a significant manner the following signs: great vigilance at the beginning, decreasing very quickly, low attentiveness, a slowness of perception and motion, a weakness in the elaboration of decision processus, certain difficulties in defining the classification of objects, a modified perception of colours, a very feeble distinction of pertinent signals and of noise, an invasion by the internal stimulus, unbalanced compared to "outside", as in sensory deprivation, a great weakness in the processus of habituation and learning, a loss of the redundancy and the constancy of the outside world (or troubles of the internal coherency, as defined by Varela). The closure, the temporal troubles (historical and present) of the integration of signals are sufficient to explain these results. A model explains the deduced hypothesis on two levels: 1) historical: the troubles of habituation and learning prevent the formation of the inner stimulus (or image, representation); 2) present: closure, ambivalence (Gödel), troubles of associations, difficulties in detecting what is pertinent, hallucinations (a "delirious" internal stimulus). The specific brain-channels seem to be normal, on the contrary the non-specific channels and the channels of integration seem troubled. The temporal trouble of "present" seems to be located on a precocious precategorical iconic level. This descriptive model does not prejudge the etiology of the disease (bibliography).

[Comparison of the waking EEG with the subjective impressions of the waking individual (author's transl)]. / Relation entre l'étude objective des éveils à l'EEG et l'auto-observation du sujet au réveil.

Sleep EEGs of 30 chronic insomnia patients are compared with the patients' subjective estimation of the duration of sleep and the number of waking periods during the night's recording. Overall, the patients overestimated the duration of sleep and, to a lesser degree, the time they awaken in the morning. The number and duration of waking periods in the night were regularly underestimated, and no correlation could be found between the estimated number of waking periods and those actually recorded on the EEG. The composition of sleep on falling asleep and on waking, when these are overestimated, showed an appreciable period of waking sleep at these times (21% and 41% respectively). The authors suggest that their results indicate that study of the transitional periods of sleep and waking may provide a better understanding of insomnia and lead to alternative therapeutic approaches. They also indicate that the shorter duration of sleep is only one aspect of insomnia and other factors are probably important.