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Biomedical subjects

H Wulf

Publications and source records attributed to H Wulf.

At least 73 records · Page 4Linked to original sources
PubMed2001

Dose-response relationship of propofol on mid-latency auditory evoked potentials (MLAEP) in cardiac surgery.

BACKGROUND: Propofol-sufentanil anaesthesia has become popular during cardiac surgery for its titrability and short recovery time. Avoidance of awareness is a major goal during cardiac surgery. We therefore investigated the dose-response relationship of propofol and cortical responses (mid-latency auditory evoked potentials, MLAEP). METHODS: One hundred patients undergoing cardiac surgery were investigated. Basic anaesthesia was performed with sufentanil (4.5 microg kg(-1) h(-1)) / flunitrazepam (9 microg kg(-1) h(-1)) infusion (control group); the other groups received in addition a loading dose of propofol 2 mg kg(-1) and a maintainance infusion of 1-3.5 mg kg(-1) h(-1). MLAEP were evaluated by using Pa/Nb-amplitudes and Nb-latencies. Haemodynamics were monitored by ECG, arterial blood pressure and cardiac function with pulmonary artery catheterization. RESULTS: In the control group, median amplitude of MLAEP decreased by 50% with a wide range, but were detectable in >90% of patients throughout surgery. Propofol suppressed amplitude Pa/Nb of MLAEP dose dependently. With 3.5 mg kg(-1) h(-1) amplitudes disappeared in >40% of patients throughout cardiac surgery. Median Nb-latencies increased in the control group from 44 to a range from 50 to 60 ms. In groups with propofol >2 mg kg(-1) h(-1), Nb-latencies, detectable in the patients without complete suppression of MLAEP, increased to median 60 ms. Haemodynamic parameters and cardiac function did not differ among the groups. The use of vasopressors was not increased even with the highest propofol dose used. CONCLUSION: The dose-response effect of propofol on auditory evoked potentials reveals that combining a loading dose of 2 mg kg-1 with a consecutive infusion of 3.5 mg kg(-1) h(-1) significantly suppresses MLAEP during cardiac surgery. Thus, auditory information may not be processed and awareness with recall becomes unlikely.

Adolescent↗
PubMed2001

Minimum local analgesic dose of plain ropivacaine vs. ropivacaine combined with sufentanil during epidural analgesia for labour.

We have used the up-and-down allocation technique to assess the relative analgesic potencies of epidural ropivacaine alone and ropivacaine combined with sufentanil 0.75 microg.ml-1 in 42 women requesting epidural analgesia in the first stage of labour. Parturients were randomly allocated to one of the two epidural solutions in a double-blind manner. The concentration of local anaesthetic was determined by the response of the previous parturient: an effective concentration (pain < or = 10 mm on a 10-cm visual analogue pain score within 30 min) resulted in a 0.01% decrease in the concentration of ropivacaine for the next parturient, an ineffective concentration resulted in a 0.01% increase. Minimum local analgesic concentration of ropivacaine alone was 0.13% (95% CI 0.12-0.13%) compared with 0.09% (95% CI 0.08-0.1%) for ropivacaine with sufentanil (p < 0.00001).

Adult↗
PubMed2001

The influence of fentanyl vs. s-ketamine on intubating conditions during induction of anaesthesia with etomidate and rocuronium.

BACKGROUND AND OBJECTIVE: In the present study, we investigated the combination of etomidate and s-ketamine with regard to its suitability for modified rapid-sequence induction using rocuronium for muscle relaxation. METHODS: In a prospective, randomized and double-blinded study, 90 patients were assigned to one of three groups for induction of anaesthesia in combination with etomidate (0.3 mg kg-1) and muscle relaxation with rocuronium (0.6 mg kg-1). The groups were as follows: (a) control, i.e. placebo; (b) fentanyl, fentanyl (1.5 microg kg-1); (c) ketamine, s-ketamine (0.5 mg kg-1). Tracheal-intubating conditions after 1 min were classified as excellent, good or poor. During the induction of anaesthesia, arterial pressure and heart rate were measured every 60 s. RESULTS: Intubating conditions were best using etomidate and s-ketamine (23 excellent, 7 good, 0 poor) compared with the control (8, 16, 6 respectively) and fentanyl groups (7, 21, 2 respectively) (P < 0.01). While heart rate and arterial pressure remained stable in the control and fentanyl groups during induction, both significantly increased in the ketamine group (P < 0.01). CONCLUSIONS: The combination of etomidate and s-ketamine for anaesthesia induction produces mostly excellent intubating conditions after 60 s using only 0.6 mg kg-1 of rocuronium. This combination of drugs may be a useful alternative, if succinylcholine needs to be avoided, for modified rapid-sequence induction.

Adult↗
PubMed2001

Complications of obstetric anaesthesia.

The present review addresses common and rare, but potentially severe complications of obstetric anaesthesia. Although several recent randomized and controlled studies on the prevention of spinal hypotension have been reported, the incidence of neurological complications caused by neuraxial blocks is estimated primarily from the results of retrospective investigations and case reports. In order to avoid potential risks in obstetrics, however, vigilance and close monitoring of the patient are critical. The adoption of published recommendations (e.g. those regarding regional techniques and coagulopathy, and difficult airway management) may help to improve the outcome for mother and child.

Journal Article↗
PubMed2001

Muscle relaxants suitable for day case surgery.

Neuromuscular blocking agents are used as adjuvants in day case anaesthesia to facilitate tracheal intubation and/or surgery. Although the majority of day case procedures are performed without the use of neuromuscular blocking agents, there are procedures, such as laparoscopic surgery, microsurgery, open eye surgery, some ear, nose and throat procedures and some paediatric procedures, which may require neuromuscular blockade. The characteristics of an ideal neuromuscular blocking agent for day case surgery are a short onset, a short clinical duration and a short recovery time, with or without reversal. It should also lack histamine release, provide haemodynamic stability, and be competitively priced. This paper reviews the neuromuscular blocking agents currently available and used, such as succinylcholine and mivacurium, low doses of an intermediate-acting neuromuscular block, such as rocuronium and the recently introduced rapacuronium. Their advantages and disadvantages are described and discussed, with special reference to the needs of day case surgery. Rapacuronium offers certain benefits compared with the currently available neuromuscular blocking agents for day care anaesthesia.

Ambulatory Surgical Procedures↗
PubMed2000

[Proxy decision in health questions and advance designations by patients. A practice-oriented review of the legal and ethical problems in treating the incompetent patient].

Except in emergencies, the medical treatment of incompetent patients also has to be based upon an informed consent between the physician and a legitimate legal representative (durable power of attorney). Consequently, the German 'Betreuungsrecht' advices persons to designate in advance such a proxy or surrogate. However, an additional court-decision is demanded, if a medical measure poses significant risks for the future health or the life of the incompetent patient. On the base of the available epidemiologic data we illustrate that neither our medical nor our legal system could realistically cope with the practical consequences of this legislation: The vast majority of our present decisions in such cases is not covered by a legally valid informed consent, which implies possible forensic consequences. This article provides relevant clinical and legal advice on how to protect the legitimate interests of all concerned within the present framework, which should urgently be revised.

Animals↗
PubMed2000

Equipment for the difficult airway in obstetric units in Germany.

STUDY OBJECTIVE: To examine the availability of specialized equipment for the difficult airway management in obstetric units of German departments of anesthesiology. DESIGN AND SETTING: An anonymous questionnaire survey was mailed to the directors of 993 German departments of anesthesiology. Completed replies were grouped by number of deliveries performed each year. MAIN RESULTS: 55.5% of the hospitals responded. Data of 449 answers were evaluated for this investigation. A difficult airway cart was available in 99.3% of the departments. More detailed investigation revealed that different shaped laryngoscope blades (74.9% of the departments), laryngeal masks (91.0%), a fiberoptic bronchoscope (85.9%), and transtracheal puncture devices (59.9%) were available in the majority of the units. However, only a minority of the departments had these devices directly available in their obstetric operating rooms (OR; laryngeal masks 36.2%, fiberoptic bronchoscope 23.9%, transtracheal puncture set 22.0%). Larger units with more than 1,000 deliveries per year provided their equipment more often directly in the obstetric OR or the facility housing the obstetric unit than did smaller units with less than 1,000 deliveries per year (p< 0.001). CONCLUSIONS: The survey of German departments of anesthesia revealed that specialized equipment for the difficult airway management often is not directly available in the obstetric OR. Anesthesiologists must familiarize themselves as to which difficult airway equipment is available in their unit and where it is stored.

Anesthesia Department, Hospital↗
PubMed2000

Pharmacokinetics of ropivacaine during extradural anesthesia for total hip replacement.

STUDY OBJECTIVE: To determine plasma concentrations of ropivacaine during epidural anesthesia with ropivacaine 10 mg/mL in patients undergoing elective total hip replacement. DESIGN: Phase III prospective study. SETTING: Orthopedic surgical unit of the University Hospital in Kiel, Germany PATIENTS: 11 ASA physical status I, II, and III patients undergoing elective total hip replacement after premedication with a benzodiazepine. INTERVENTIONS: Peripheral venous plasma samples were collected prior to and 10, 15, 20, 30, 45, 60, 90, and 120 minutes following the epidural dose. MEASUREMENTS AND MAIN RESULTS: After solid phase extraction, plasma concentrations of ropivacaine were measured by high-performance liquid chromatography (HPLC). Free unbound concentrations were determined after ultracentrifugation. In 9 of 11 patients excellent epidural anesthesia was achieved with an initial dose of 144 +/- 13 mg (120 to 150 mg) of ropivacaine corresponding to a dose of 1.9 +/- 0.4 mg/kg body weight. We suspected inadvertent intravascular catheter malposition in one case. Peak plasma concentrations occurred after 20 minutes (10 to 30 min) with a mean of 1.38 +/- 0.42 micrograms/mL (range 0.95 to 2.26 micrograms/mL). Maximum unbound free plasma concentrations of ropivacaine were 0.05 +/- 0.03 microgram/mL (range 0.02 to 0.13 microgram/mL). CONCLUSION: Ropivacaine 10 mg/mL proved to be suitable for epidural anesthesia for total hip replacement. The plasma concentrations after 120 to 200 mg of its epidural application were not associated with signs of local anesthetic toxicity in patients pretreated with benzodiazepines, even in one case of suspected inadvertent intravascular application.

Adult↗
PubMed2000

The pharmacokinetics of caudal ropivacaine 0.2% in children. A study of infants aged less than 1 year and toddlers aged 1-5 years undergoing inguinal hernia repair.

This study evaluates the pharmacokinetics of ropivacaine in children after caudal epidural injection. Twenty male children undergoing inguinal hernia repair were enrolled after ethics committee approval and informed parental consent, and were grouped according to age (10 'infants' aged less than 1 year and 10 'toddlers' aged 1-5 years). After induction of general anaesthesia, caudal epidural injection using ropivacaine 0.2% 1 ml.kg-1 was performed. Plasma concentrations of ropivacaine in the first 2 h after injection were determined by reversed-phase high-pressure liquid chromatography. Caudal blockade with ropivacaine 2 mg.ml-1 resulted in mean (SD) peak plasma concentrations of 0.73 [0.27] microg.ml-1 in infants and 0.49 [0.21] microg.ml-1 in toddlers (p < 0.01). Maximum plasma concentrations occurred after a median [range] period of 60 [15-90] min and 52.5 [30-120] min in infants and toddlers, respectively. Two infants (weighing 3.8 and 5.0 kg) showed the highest individual maximum plasma concentrations: 1.31 and 1.11 microg.ml-1. No clinical signs of local anaesthetic toxicity were observed. The results of the present investigation suggest that, from a pharmacokinetic point of view, caudal blockade using ropivacaine 0. 2% 1 ml.kg-1 can be regarded as a safe technique in children, i.e. in infants as well as in toddlers.

Amides↗
PubMed1999

[Postoperative nausea and vomiting following stabismus surgery in children. Inhalation anesthesia with sevoflurane-nitrous oxide in comparison with intravenous anesthesia with propofol-remifentanil].

BACKGROUND: Postoperative nausea and vomiting (PONV) is still one of the major problems in strabismus surgery, especially in children. In recent years many studies have been published, suggesting that choosing propofol as the anaesthetic agent may help to reduce the high incidence of PONV in children undergoing strabismus surgery. Experience with remifentanil in children is still very limited and little is known, whether propofol in combination with this new short acting opioid is also superior regarding PONV in squint surgery compared to sevoflurane/N2O. Additionally, little is known, whether the type of operation or the muscle which is operated on has any influence with respect to PONV. METHODS: Following sample size estimation, ethics committee approval and parents informed consent in a prospective, randomised, observer-blind study 105 ASA I and II children aged 3-8 years scheduled for elective strabismus surgery were assigned into one of the following groups: Group TIVA (propofol/remifentanil, n = 53): anaesthesia was induced by remifentanil 0.5 microgram kg-1 min-1 over 2 min (loading phase), followed by 3 mg kg-1 propofol along with 30% O2 in air. After endotracheal intubation anaesthesia was maintained initially with remifentanil 0.25 microgram kg-1 min-1 and propofol 10 mg kg-1 h-1 by constant infusion. In the course of the operation the infusions of the anaesthetics were adjusted to the decreasing need for anaesthesia. Group VOLATIL (sevoflurane/N2O, n = 52): anaesthesia was induced by inhalation of sevoflurane along with 50% O2 in N2O. After endotracheal intubation anaesthesia was maintained with sevoflurane 1.0-1.5 MAC along with 30% O2 in N2O and in the course of the operation the administration of the inhaled anaesthetics was adjusted correspondingly. Preoperatively collected data included gender, age, weight and history of PONV. Intraoperatively collected data consisted of data belonging to routine monitoring (heart rate, blood pressure, peripheral oxygen saturation and temperature) as well as the duration of the operation and anaesthesia and specific data regarding the operation (including the number and type of muscles as well as the kind of operation). Data collected within the first 24 hours postoperatively in the recovery room and on the ward by blinded observers included any PONV events as well as the antiemetics and analgesics applied. RESULTS: Vomiting was observed less frequently in the TIVA-group than in the VOLATIL-group (21 of 53 vs. 32 of 52, p = 0.03) within the first 24 hours postoperatively. Posterior fixation suture ("faden-operation") compared to other operations was followed rather frequently by nausea and vomiting (30 of 44 and 33 of 44, respectively), whereas recessions were rarely associated with nausea and vomiting (12 of 35 and 9 of 35, respectively). CONCLUSIONS: TIVA with propofol/remifentanil proved to be a suitable form of anaesthesia for children in this setting. Propofol showed advantages over sevoflurane/N2O with respect to PONV after squint surgery in children also when applied in the combination with remifentanil. TIVA with propofol/remifentanil may therefore be one way to reduce the high incidence of PONV in this setting, bearing in mind, that PONV is not only influenced by the regimen of the general anaesthesia but rather by the combination of many other factors, in particular the type of operation.

Anesthesia, Inhalation↗
PubMed1999

[Prophylaxis of nausea and vomiting after pelviscopy. Dolasetron or MCP in comparison with placebo].

BACKGROUND: Gynaecological surgery including laparoscopy is frequently associated with PONV. Therefore, choosing an anaesthetic with only little side effects in operations eligible for outpatient surgery is at least as important as applying anaesthetics that enable fast-tracking. STUDY GOAL: To assess the incidence and severity of PONV after balanced desflurane-N(2)O-anaesthesia and to compare the antiemetic efficacy of dolasetron or metoclopramide versus placebo. METHODS: 120 ASA physical status I and II women aged 18 to 55 scheduled for elective laparoscopic surgery were enrolled. Anaesthesia was standardized: fentanyl (2 microg/kg), etomidate (0. 25 mg/kg) and succinylcholine (1 mg/kg) for induction and desflurane 3-5% et along with 30% O(2) in N(2)O, fentanyl (max. 0.1 mg/h) and cis-atracurium for maintenance. Patients were randomly allocated to receive one of the following: dolasetron 12.5 mg (group-D), metoclopramide 10 mg (group-M) or placebo (group-P). RESULTS: Within the first 24 h, postoperative nausea (PON) and postoperative vomiting (POV) were reduced significantly in group D (38%/19%) and group M (36%/27%) compared to group P (69%/56%). Furthermore, PON and POV proved to be less intense in groups D and -M compared to group P: Episodes of severe nausea were recorded 17 times in 10 patients (17/10) in group P, compared to 5/4 in group M and 5/3 in group D, episodes of repeated vomiting 13 times in 8 patients (13/8) in group P, compared to 2/2 in group M and 2/1 in group D. CONCLUSIONS: Our results confirm the increased incidence of PONV after gynaecological laparoscopic surgery under balanced anaesthesia compared to the predicted rates. Both dolasetron and metoclopramide proved to be effective prophylactic measures. Given a PONV-incidence of 38% in group D and 39% in group M, it is doubtful, whether the anaesthetic technique chosen in this study is the most suitable regimen for ambulatory gynaecological laparoscopies.

Adolescent↗
PubMed1999

[Pain therapy after thoracoscopic interventions. Do regional analgesia techniques (intercostal block or interpleural analgesia) have advantages over intravenous patient-controlled opioid analgesia (PCA)?].

Systemic opioids and thoracic epidural analgesia are common techniques used to provide post-operative analgesia following thoracoscopy (video-assisted thoracic surgery). The aim of the present prospective randomised study was to evaluate the efficacy of two less invasive analgesic techniques, intercostal blocks (ICB) and interpleural analgesia (IPA). After approval from the ethics committee and informed consent from the patients, 36 patients scheduled for thoracoscopic surgery were randomly assigned to a group for postoperative pain management: group ICB: intercostal blocks of the segments involved with 5 ml 0.5% bupivacaine at the end of surgery and 6 h later; group IPA: interpleural analgesia with 20 ml 0.25% bupivacaine applied every 4 h using a catheter placed during surgery near the apex of the interpleural space; control group: IV-opiod-PCA with piritamide. Patients in the ICB and IPA groups had access to pain relief by PCA with piritramide as well. Additional medication for all groups if the analgesia was insufficient consisted of metamizol. There were no significant differences in piritramide consumption between the two regional analgesia groups and the control group up to the 3rd and 7th postoperative day. Up to the 7th day piritramide consumption in group ICB was 78 mg, in group IPA 75 mg and 80 mg in the control group. Patients in group ICB showed significantly less pain at rest measured by the visual analogue scale (VAS) on the 1st postoperative day (U-test, P < 0.05), but otherwise there were no statistical differences regarding pain scores. Respiratory parameters such as forced vital capacity, forced expiratory volume, peak flow and the Tiffeneau test (FVC, FEV1, PF, FEV1/FVC) were reduced significantly after thoracoscopy and showed a slow recovery in all three groups without significant intergroup differences. Thoracoscopic surgery causes less and shorter lasting pain in comparison to thoracotomy. Nevertheless, effective pain management is necessary. We could not demonstrate a significant reduction in piritramide consumption for the techniques of regional analgesia tested here (ICB, IPA). We conclude that the use of these techniques is not complementary after thoracoscopy, since an opioid (PCA with piritramide) combined with a non-opioid (metamizol) resulted in satisfactory analgesia.

Adult↗