P. Marhofer

Ultrasonographic guidance reduces the amount of local anesthetic for 3-in-1 blocks.

Background and Objectives. Recently it has been demonstrated that the use of ultrasound (US) improves the onset time and the quality of sensory block for 3‐in‐1 blocks compared with conventional nerve stimulator (NS) techniques. The present study was designed to evaluate if US guidance for 3‐in‐1 blocks reduces the amount of local anesthetic compared to NS guidance. Methods. After institutional approval and informed consent, 60 patients undergoing hip surgery following trauma were randomly assigned to three groups of 20 patients each. In group A, the 3‐in‐1 block was performed using US guidance with 20 mL 0.5% bupivacaine. Group B received 20 mL 0.5% bupivacaine, and group C received 30 mL 0.5% bupivacaine during NS guidance. The quality and the onset time was assessed by pinprick test in the central sensory region of each of the three targeted nerves and compared with the contralateral leg every 10 minutes for 1 hour by a blinded observer. The rating was undertaken using a scale from 100% (uncompromised sensibility) to 0% (no sensation). Results. Overall success for the 3‐in‐1 block in group A was 95% and in groups B and C 80%. Onset time was significantly shorter in the US‐guided group compared with both NS‐guided groups (group A 13 ± 6 minutes; group B 27 ± 12 minutes; and group C 26 ± 13 minutes; P < .01 to groups B and C). Quality of sensory block was significantly better in group A (4% ± 5% of initial value) compared with groups B and C (group B 21% ± 11% of initial value, P < .01 to group A; group C 22% ± 19%, P < .01 to group A). Conclusion. The amount of local anesthetic for 3‐in‐1 blocks can be reduced by using US guidance compared with the conventional NS‐guided technique.

Brachial plexus anaesthesia in children: lateral infraclavicular vs axillary approach.

Summary Background:u2002Brachial plexus blockade is a well‐established technique in upper‐limb surgery. In paediatric patients, the axillary route is usually preferred to infraclavicular approaches because of safety considerations. Recent reports on a lateral infraclavicular approach offering greater safety in adults prompted us to perform a prospective randomized study to assess the analgesic efficacy of axillary vs lateral vertical infraclavicular brachial plexus (LVIBP) blocks in paediatric trauma surgery.

A prospective study comparing the analgesic efficacy of levobupivacaine, ropivacaine and bupivacaine in pediatric patients undergoing caudal blockade.

Background:u2002 The aim of our study was to compare postoperative analgesic efficacy, analgesic duration and motor blockade of levobupivacaine, ropivacaine and bupivacaine administered caudally in equal concentrations to children undergoing elective minor surgery.

Incidence and therapy of midazolam induced hiccups in paediatric anaesthesia.

A prospective, randomized and double blind study was undertaken to determine the incidence and a possible dose‐ or age‐dependence of hiccups in children premedicated with rectal midazolam and to investigate the treatment of hiccups by intranasal ethyl chloride spray application. Two hundred ASA physical status 1 and 2 children, weighing 3.0 to 15.0 kg, scheduled for minor surgery, were randomly assigned to be given either 0.5 mg·kg−1 midazolam(n=100) or 1.0 mg·kg−1 midazolam (n=100) administered rectally. If hiccups were observed during a period of 20 min after premedication with midazolam, these children were treated after 3 min of hiccups with two short intranasal applications of ethyl chloride spray. Hiccups occurred in 22% of children in the 0.5 mg·kg−1 group and 26% in the 1.0 mg·kg−1 group (n.s.). The intranasal application with ethyl chloride was successful in 100% in both groups. The mean age levels between children with or without hiccups were 5±9 months vs 21±19 months (P<0.01) in the 0.5 mg·kg−1 group and 6±7 months vs 20±14 months (P<0.01) in the 1.0 mg·kg−1 group. Intranasal application of ethyl chloride spray seems to be an effective therapy for midazolam induced hiccups in paediatric anaesthesia. The incidence of these hiccups is highly age significant, but not dose dependent.

Clonidine as adjuvant for mepivacaine, ropivacaine and bupivacaine in axillary, perivascular brachial plexus block.

PurposeTo evaluate the effects of clonidine on three local anesthetics (mepivacaine 1%, ropivacaine 0.75% and bupivacaine 0.5%) with comparable potency and almost the same concentration-response relationship.MethodsOne hundred and twenty trauma-patients were randomly allocated into six groups. In the control-groups (Mo/Ro/Ro/Bo) brachial plexus was performed using 40 mL of local anesthetic plus I mL of NaCL 0.9%. In the clonidine-groups (Mc/Rc/Bc) brachial plexus was performed using each 40 mL of drug plus I mL (0.150 mg) of clonidine. Onset-time and the duration of the sensory block were recorded. Data are expressed as mean ± SD.ResultsAccording to the average sensory block determined by a visual analog scale in the median, ulnar and radial nerve distributions and ranging from 100 (no sensory blockade) to 0 (complete sensory blockade), both mepi-groups showed a rapid onset (at 10 min: —Mo 20 ± 15 /Mc 19 ± 14; at 30 min: -Mo 3 ± 4 /Mc 5 ± 4). The ropi and bupi-groups both had a longer onset time (at 10 min:-Ro 23 ± 19I Re 25 ± 22 /Bo 24 ± 15; at 30 min -Ro / 0 ± 6/ Rc 11 ± 6 /Bo 12 ± 4). The onset time in group-Bc was significantly prolonged (at 10 min: −45 ± 21; at 30 min: −20 ± 6). Duration of motor blockade was prolonged by clonidine only in the mepivacaine and bupivacaine groups; (in minutes:Mo 212 ± 47 -Mc 468 ± 62;Ro 702 ± 52-Rc 712 ± 82;Bo 728 ± 36-Bc 972 ± 72).ConclusionThe present study shows that the addition of clonidine has a different impact on each of the three local anesthetics investigated in terms of onset and duration of block.RésuméObjectifÉvaluer les effets de la clonidine sur trois anesthésiques locaux à puissance comparable (la mépivacaïne à 1 %, la ropivacaïne à 0,75% et la bupivacaïne à 0,5%) qui présentent une relation concentration-réponse presque similaire.MéthodeCent vingt patients victimes de traumatisme ont été répartis au hasard en six groupes. Dans les groupes témoins (Mo/Ro/Bo), le bloc du plexus brachial comprenait 40 mL d’anesthésique local plus I mL de NaCL à 0,9%. Dans les groupes clonidine (Mc/Rc/Bc), il comprenait 40 mL d’anesthésique local plus I mL (0,150 mg) de clonidine. Le délai d’installation et la durée du blocage sensitif ont été notés et exprimés comme la moyenne ± l’écart type.RésultatsD’après le bloc sensitif moyen, déterminé par une échelle visuelle analogique appliquée aux distributions des nerfs médian, cubital et radial et qui s’étend de 100 (aucune anesthésie) à 0 (blocage sensitif complet), les deux groupes de mépivacaïne ont indiqué une installation rapide (à 10min: — Mo 20 ± 151 Mc 19 ± 14;à30 min:-Mo 3 ± 4/Mc 5 ± 4). Les groupes ropivacaïne et bupivacaïne ont présenté un plus long délai d’installation (à 10 min: — Ro 23 ± 19 / Rc 25 ± 22 /Bo 24 ± 15; à 30 min: — Ro 10 ± 6/Rc 11 ± 6/ Bo 12 ± 4). Le délai d’installation s’est prolongé de façon significative dans le groupe — Bc (à 10 min: — 45 ± 21; à 30 min: — 20 ± 6). La durée du blocage moteur a été prolongée par la clonidine dans les groupes mépivacaïne et bupivacaïne seulement; (en minutes: Mo 212 ± 47 – Mc 468 ± 62; Ro 702 ± 52 – Rc 712 ± 82; Bo 728 ± 36-Bc 972 ± 72).ConclusionLa présente étude montre que l’addition de clonidine provoque des effets différents sur chacun des trois anesthésiques locaux expérimentés quant au délai d’installation et à la durée de l’anesthésie.

Axillary brachial plexus block for treatment of severe forearm ischemia after arterial cannulation in an extremely low birth-weight infant

Severe limb ischemia after arterial catheterization in neonates and premature infants is a well‐recognized problem. The usual treatment of ischemic injuries includes removal of the catheter and elevation of the effected limb. If unsuccessful, tissue necrosis and loss may follow. We report the case of a 700u2003g infant with severe distal forearm ischemia after right radial and ulnar artery catheterization. Immediate removal of the arterial line did not improve ischemia. Thirty‐six hours later a brachial plexus block via the axillary approach with 0.5u2003ml bupivacaine 0.125% was performed resulting in rapid improvement, restricting ischemia eventually to fingers II–V as well as the distal part of the thumb. Brachial plexus blockade and active vasodilatation in tiny neonates after severe local ischemia are discussed.

The effects of clonidine on ropivacaine 0.75% in axillary perivascular brachial plexus block.

The new long‐acting local anesthetic ropivacaine is a chemical congener of bupivacaine and mepivacaine. The admixture of clonidine to local anesthetics in peripheral nerve block has been reported to result in a prolonged block. The aim of the present study was to evaluate the effects of clonidine added to ropivacaine on onset, duration and quality of brachial plexus block.

Ultraschall in der Regionalanästhesie

ZusammenfassungIn der Regionalanästhesie stellt die Lokalisation der zu blockierenden Nerven eine besondere Herausforderung dar. Seit der Zeit der ersten Regionalanästhesieverfahren vor ca. 100 Jahren ist die wesentliche Einschränkung dieser Methodik in den nicht befriedigenden Erfolgsraten und den spezifischen Risiken zu sehen. Auch durch Variation des Zugangsweges zu den verschiedenen Nerven oder durch verschiedene Identifikationsmethoden konnte keine ideale Blockadetechnik erarbeitet werden, die gleichzeitig eine Erfolgsquote von 100% ermöglicht und die Risiken minimiert. Die klinische Einführung verschiedener Hilfsmittel, wie die Nervenstimulation oder die Dopplersonographie, erbrachte trotz unumstrittener Verbesserungen bisher keine statistisch signifikanten Vorteile. In den letzten Jahren zeigte sich in der perioperativen Versorgung aufgrund der nachzuweisenden Vorteile und Möglichkeiten ein deutlicher Trend in Richtung Regionalanästhesie. Mehrere Arbeitsgruppen entwickelten Methoden zur sonographischen Identifikation von Nerven oder des Epiduralraumes und zur sicheren Platzierung von Nadeln oder Kathetern unter Berücksichtigung der gewonnenen Informationen. Die Applikation von Kathetern und die Injektion des Lokalanästhetikums kann auf diese Weise gezielt und kontrolliert durchgeführt werden. Obwohl die Sonographie im Rahmen der Regionalanästhesie ein Verfahren ist, das bereits 10 Jahre alt ist, gibt es bis zum heutigen Tag nur wenige regionalanästhesiologisch tätige Anästhesisten, die dieses Verfahren einsetzen können. Allerdings steigt das Interesse an dieser Methodik deutlich an, insbesondere aus Gründen der Qualitätssicherung. Zentrale Gremien haben festgestellt, dass diese Methodik zukunftsweisend sein wird. Vielleicht wird sich sogar die Aussage von Alon P. Winnie für die ultraschallgestützte Regionalanästhesie bewahrheiten: “Sooner or later someone will make a sufficiently close examination of the anatomy involved, so that exact techniques will be developed.”AbstractThe localisation of the nerve to be blocked is one of the special challenges in local anaesthesia. Since the first time local anaesthesia procedures were carried out approximately 100 years ago, the basic limitations of this method have always been the unsatisfactory success rate and the specific risks involved. Even by variation of the access route to the various nerves and use of different identification methods, no ideal blockade technique has been found which allows a 100% success rate and at the same time reduces the risks to a minimum. The clinical introduction of various aids, such as nerve stimulation or Doppler sonography, have brought no statistically significant advantages despite showing clear improvements. In recent years there has been a trend towards local anaesthesia in perioperative care due to the proven advantages and range of possibilities. Several working groups have developed methods for the sonographic identification of nerves or the epidural space and to an exact placing of needles or catheters from the information obtained. In this way the application of catheters and the injection of local anaesthetic agents can be carried out in an accurate and controlled manner. Although sonography is a procedure which has been used in local anaesthesia for over 10 years, there are at present only few practising local anaesthetists who can use this method. However, interest in this method is growing especially due to the aspect of quality assurance. Organising committees have established that this method will be the future direction. Perhaps even the prediction of Alon P. Winnie for ultrasound-guided local anaesthesia will become true: “Sooner or later someone will make a sufficiently close examination of the anatomy involved, so that exact techniques will be developed.”

Cardiovascular effects of 6% hetastarch and lactated Ringer's solution during spinal anesthesia☆

BACKGROUND AND OBJECTIVESnThe purpose of this prospective, randomized, double-blinded study was to compare the hemodynamic effects of 6% hetastarch with lactated Ringers solution and to determine the main reasons for hemodynamic impairment following spinal anesthesia in elderly patients undergoing emergent hip surgery.nnnMETHODSnAfter receiving institutional approval and informed consent, we enrolled 24 ASA physical status III patients for this study. Hemodynamics were recorded with pulmonary artery and arterial catheters and an electrocardiogram. Following fluid administration with either 500 mL 6% hetastarch (group H) or 1500 mL lactated Ringers solution (group R), spinal anesthesia was administered with 3.0 mL 0.5% bupivacaine (isobaric). Hemodynamic measurements were recorded prior to fluid administration, before spinal anesthesia, and 10, 20, and 30 minutes following spinal anesthesia and reported as relative changes relating to baseline.nnnRESULTSnAlthough the hemodynamic measurements after spinal anesthesia remained stable in group H throughout the observation period, blood pressure, central venous pressure, pulmonary artery (PA) wedge pressure and systemic vascular resistance decreased significantly in group R (blood pressure: -7 +/- 10 vs - 14 +/- 8% 30 minutes after spinal anesthesia, P < .05 to group R; central venous pressure: 51 +/- 106 vs -26 +/- 27% 10 minutes, 63 +/- 89 vs -36 +/- 30% 20 minutes and 73 +/- 112 vs -33 +/- 29% 30 minutes after spinal anesthesia, P < .01 to group R; PA wedge pressure: 40 +/- 37 vs -5 +/- 40% 10 minutes, 40 +/- 35 vs -23 +/- 32% 20 minutes and 38 +/- 36 vs -23 +/- 32% 30 minutes after spinal anesthesia, P < .01 to group R; systemic vascular resistance: -10 +/- 16 vs -18 +/- 7% 20 minutes and -10 +/- 15 vs - 19 +/- 12% 30 minutes after spinal anesthesia, P < .05 to group R).nnnCONCLUSIONSnSix percent hetastarch minimizes the hemodynamic responses during spinal anesthesia in elderly patients undergoing emergent hip surgery. In this study population, spinal anesthesia-induced hemodynamic impairment is caused by decreases in cardiac filling pressures and systemic vascular resistance.

S(+)-ketamine in paediatric anaesthesia

The dissociative anaesthetic agent ketamine hydrochloride has been in widespread clinical use for over 30 years. It produces a cataleptic state characterized clinically by a functional and electrophysiological dissociation between thalamic, cortical and limbic systems in the brain. Ketamine produces dissociative anaesthesia and extensive analgesia, which safely and effectively enables treatment for a wide variety of short, painful, surgical or critical care procedures. The anaesthetic and analgesic properties of ketamine are particularly attractive for analgesia ⁄ sedation and rectal premedication of paediatric patients (1). In many countries, ketamine is currently available as a mixture of two enantiomers, S(+)-ketamine and R(–)-ketamine, in equal proportions. Several studies in adults (2–5) have compared the efficacy and side-effects of S(+)-ketamine with those of racemic ketamine. Among the findings from these investigations, it has been noted that the anaesthetic potency of S(+)-ketamine doubles the anaesthetic effects of racemic ketamine (5). Other noted advantages of S(+)-ketamine include fewer psychomotor sideeffects (3), less salivation (2) and a shorter recovery time (4) compared with racemic ketamine. As a result, in some European countries, racemic ketamine has been replaced by its S(+)-enantiomer. In children, studies performed to date have tested intravenous (6) and intramuscular administration (7) of S(+)-ketamine for sedation and analgesia, rectal administration (8) of S(+)-ketamine for premedication, and caudal administration, both by itself (7) and together with local anaesthetics (9) or other additives (10), for perioperative analgesia. In children aged 8 months to 7 years, a sedation technique based on rectal and intravenous administration of a combination of midazolam and S(+)-ketamine has been shown to be a safe and useful alternative to general anaesthesia (6). Using this sedation technique, induction and discharge times were significantly reduced compared with a control group receiving general anaesthesia. Rectal premedication using S(+)-ketamine in children, for the purposes of reducing perioperative stress and facilitating the induction of inhaled anaesthesia, was found to be less effective than rectal midazolam alone (8). The chosen dose of 1.5 mgÆkg rectal S(+)-ketamine was found to have a poor anaesthetic effect and a high incidence of side-effects. According to the authors of this study, a higher dose of rectal S(+)-ketamine would be necessary to provide sufficient premedication in children. The dose–response relationship and the pharmacokinetic profile of the drug after rectal administration remain to be determined (11). Based on the results of previous studies that tested the epidural and caudal administration of racemic ketamine (12,13), several recent investigations in children have examined the caudal approach for using S(+)-ketamine (7,9,10,14,15). Racemic ketamine has been used for paediatric caudal blocks (13) and has demonstrated an analgesic potency comparable with that of bupivacaine. However, because of possible neurotoxicity of preservatives added to commercially available racemic ketamine preparations (16), the caudal use of the drug was not recommended. Considering that S(+)-ketamine is available as a preservative-free solution, and that several experimental investigations (17,18) have failed to demonstrate any neurotoxicity of single or repeated intrathecal doses of preservative-free ketamine, this drug has the potential for epidural or caudal use. Marhofer et al. (14) found that caudal administration of S(+)-ketamine 1.0 mgÆkg combined with inhaled anaesthesia in children for inguinal hernia repair provided equipotent intraand postoperative analgesia compared with 0.25% bupivacaine 0.75 mlÆkg with epinephrine 1 : 200 000. The Paediatric Anaesthesia 2003 13: 185–187