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Biomedical subjects

F Servin

Publications and source records attributed to F Servin.

At least 19 recordsLinked to original sources
PubMed2004

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.

Abdomen↗
PubMed2004

Propofol sedation using Diprifusor target-controlled infusion in adult intensive care unit patients.

This multicentre, non-comparative study investigated the range of target blood propofol concentrations required to sedate 122 adult intensive care patients when propofol was administered using Diprifusor target-controlled infusion systems together with opioid analgesia. Depth of sedation was assessed with a modified Ramsay score and the target blood propofol setting was adjusted to achieve the sedation desired for each patient. A desired level of sedation was achieved for 84% of the sedation period. In postcardiac surgery patients the median time-weighted average propofol target setting was 1.34 microg.ml(-1) (10th - 90th percentiles: 0.79-1.93 microg.ml(-1)). Values in brain injured and general ICU patients were 0.98 (10th - 90th percentiles: 0.60-2.55) microg.ml(-1) and 0.42 (10th - 90th percentiles: 0.16-1.19) microg.ml(-1), respectively. Measured propofol concentrations were generally close to values predicted by the Diprifusor system. Target settings in the range of 0.2-2.0 microg.ml(-1) are proposed for propofol sedation in this setting with titration as required in individual patients.

Adult↗
PubMed2001

[Target controlled infusion (TCI) anesthesia using propofol. Assessment of training and practice in the operating room].

OBJECTIVE: To evaluate overall awareness of TCI and the need for training in the TCI technique. To assess, among trained anaesthetists, the value of the session and the impact of TCI technique on their working practice. STUDY DESIGN: Two prospective domestic surveys during the first quarter of 1999. METHODS: Three hundred anaesthetists representative of French anaesthetists as a whole, and 336 anaesthetists who had taken part in a training course. RESULTS: The notoriety of TCI was high and greater in the public sector compared with the private sector. Almost 3/4 of anaesthetists believed that training was necessary but only four anaesthetists out of ten TCI users said they had taken part in training sessions. After the training session nine anaesthetists out of ten became TCI users and would have recommended the training course despite the low number and variety of anaesthetic procedures observed during the practical part of training. The main difficulties reported during initial use were the choice of target concentrations and the management of drug interactions. Familiarisation to the technique was rapid (less than 20 procedures). Despite the lack of long experience (< 6 months for more than 2/3 of them), TCI appeared to be more likely used for anaesthesia of average duration. CONCLUSIONS: TCI was perceived to be an innovative concept with a requirement of a specific training. This preliminary appraisal of training sessions was generally satisfactory but underline a need for future training sessions focused on practical aspects.

Anesthesia, Intravenous↗
PubMed1999

[Accessory anesthetic breathing systems: verification before use].

Accessory or ancillary anaesthesia breathing systems can be defined as all those connected to the fresh gas outlet of the anaesthetic apparatus and used instead of the circle system associated with the ventilator, which is the main circuit. They include: the Mapleson systems, the systems with a nonrebreathing valve and the disposable systems with a carbon dioxide absorber. They can be a cause of major accidents when not checked before and monitored during use. This technical note describes techniques of preanaesthetic checking and monitoring during anaesthesia.

Anesthesia, Closed-Circuit↗
PubMed1998

[Pros or cons of accessory anesthetic circuits. I. Arguments for their use].

In addition to the circle breathing system, which represents the main circuit of the anaesthetic machine, the use of an accessory breathing system (ABS), either a partial rebreathing system according to Mapleson's classification, or a system including a non-rebreathing valve, is appropriate for the anaesthetic management of many patients, depending on their physical status, age, indication and duration of surgery. The same safety rules, namely full checking procedure before use of the system and monitoring of inhaled gases and end-tidal CO2 must be applied as for the main circle system. Potential complications resulting from non compliance with these rules cannot be considered valuable reasons for denying the use of breathing systems that have safely been used for decades in millions of patients.

Adult↗
PubMed1997

[Target-controlled intravenous anesthesia].

Target-controlled infusion (TCI) is a new delivery system for i.v. anaesthetic agents with which the anaesthetist targets a plasma drug concentration to achieve a predetermined effect. With this system, the tedious task of calculating the amount of administered drug required to achieve the target concentration is left in charge of a microprocessor which commands the infusion device. TCI has long been used only by a few research teams, but this year a much wider field opens to this delivery system through marketing of Diprifusor, a TCI system specifically designed for administration of propofol in everyday practice. This article describes the rationale for administering i.v. agents through TCI delivery systems, the pharmacokinetic basis of TCI, the regulations and a broad overview of clinical applications, both recent and yet to come.

Anesthesia, Intravenous↗
PubMed1997

Emergence of elderly patients from prolonged desflurane, isoflurane, or propofol anesthesia.

UNLABELLED: Recovery from prolonged anesthesia might be compromised in elderly patients. Desflurane (DES) may be particularly well suited to achieve a rapid postoperative recovery because of its low lipid solubility. Postoperative recovery was compared in 45 elderly patients randomized to receive either DES, isoflurane (ISO), or propofol (PRO) to maintain anesthesia. Anesthesia was induced with PRO, vecuronium, and fentanyl and maintained with N2O, fentanyl, and the study drug. Times from end of anesthesia to tracheal extubation, eye opening and hand squeezing on command, and ability to state name and date of birth were recorded. Sedation and psychometric evaluation were tested 0.5, 1, 1.5, 2, and 24 h postoperatively. Results are given as means +/- SD. Differences among were analyzed by chi2 or analysis of variance. P < 0.05 compared with DES was considered significant. After a prolonged anesthesia (199 +/- 57 min with DES), immediate recovery times were significantly shorter with DES than with ISO or PRO (times to eye opening: 5.6 +/- 3.4 min, 11.5 +/- 8.4 min, and 11.9 +/- 7.6 min; times to extubation: 6.9 +/- 3 min, 13.1 +/- 8.9 min, 9.9 +/- 6.5 min for DES, ISO, and PRO, respectively). Intermediate recovery, as measured by psychometric testing, sedation levels, and time to discharge from the postanesthesia care unit, was similar in the three groups. In this study, DES provided a transient advantage compared with ISO or PRO with respect to early recovery after prolonged general anesthesia in elderly patients. IMPLICATIONS: Recovery from prolonged anesthesia can sometimes be problematic in elderly patients. We evaluated 45 elderly patients who received either desflurane, isoflurane, or propofol for anesthesia. We found that desflurane provided a transient advantage in terms of postoperative recovery, but whether this difference is clinically important remains to be demonstrated.

Aged↗
PubMed1997

Remifentanil: when and how to use it.

Remifentanil is a new potent mu-agonist with a unique pharmacokinetic profile due to a rapid metabolism by non-specific tissue esterases. As a consequence, remifentanil pharmacokinetics are not modified by severe renal or hepatic dysfunction. During general anaesthesia, any dosage of remifentanil may be used without undue lengthening of emergence times. In cardiac surgery, remifentanil combines the requirement for intra-operative control of stress responses and rapid recovery. The rapid termination of remifentanil action warrants modifications of the current practice concerning early postoperative pain control. Remifentanil may be used as a sedative during monitored analgesia, or as a postoperative analgesic in spontaneously breathing patients, provided bolus doses are avoided. Remifentanil may increase patients' safety by eliminating the risk of delayed respiratory depression, but its correct use requires major changes in our prescribing habits.

Analgesics, Opioid↗
PubMed1996

Ketamine and norketamine plasma concentrations after i.v., nasal and rectal administration in children.

It has been suggested that nasal administration of ketamine may be used to induce anaesthesia in paediatric patients. We have examined the pharmacokinetics of ketamine and norketamine after nasal administration compared with rectal and i.v. administration in young children. During halothane anaesthesia, 32 children, aged 2-9 yr, weight 10-30 kg, were allocated randomly to receive ketamine 3 mg kg-1 nasally (group IN3) or ketamine 9 mg kg-1 nasally (group IN9); ketamine 9 mg kg-1 rectally (group IR9); or ketamine 3 mg kg-1 i.v. (group IV3). Venous blood samples were obtained before and up to 360 min after administration of ketamine. Plasma concentrations of ketamine and norketamine were measured by gas liquid chromatography. Statistical comparisons were performed using ANOVA and the Kruskall-Wallis test, with P < 0.05 as significant. Mean plasma concentrations of ketamine peaked at 496 ng ml-1 in group IN3 within 20 min, 2104 ng ml-1 in group IN9 within 21 min, and 632 ng ml-1 in group IR9 within 42 min. Plasma concentrations of norketamine peaked at approximately 120 min after nasal ketamine, but appeared more rapidly after rectal administration of ketamine and were always higher than ketamine concentrations in the same situation. Calculated bioavailability was 0.50 in groups IN3 and IN9 and 0.25 in group IR9. We conclude that nasal administration of low doses of ketamine produced plasma concentrations associated with analgesia, but using high doses via the nasal route produced high plasma concentrations of ketamine similar to those that induce anaesthesia. However, the large volume of ketamine required was partly swallowed and led to an unacceptable variability of effect that precludes this route for induction of anaesthesia.

Administration, Intranasal↗