Ultrasonographic guided axillary plexus blocks with low volumes of local anaesthetics: a crossover volunteer study.

Our study group recently evaluated an ED(95) local anaesthetic volume of 0.11 ml.mm(-2) cross-sectional nerve area for the ulnar nerve. This prospective, randomised, double-blind crossover study investigated whether this volume is sufficient for brachial plexus blocks at the axillary level. Ten volunteers received an ultrasonographic guided axillary brachial plexus block either with 0.11 ('low' volume) or 0.4 ('high' volume) ml.mm(-2) cross-sectional nerve area with mepivacaine 1%. The mean (SD) volume was in the low volume group 4.0 (1.0) and 14.8 (3.8) ml in the high volume group. The success rate for the individual nerve blocks was 27 out of 30 in the low volume group (90%) and 30 out of 30 in the high volume group (100%), resulting in 8 out of 10 (80%) vs 10 out of 10 (100%) complete blocks in the low vs the high volume groups, respectively (NS). The mean (SD) sensory onset time was 25.0 (14.8) min in the low volume group and 15.8 (6.8) min in the high volume group (p < 0.01). The mean (SD) duration of sensory block was 125 (38) min in the low volume group and 152 (70) min in the high volume group (NS). This study confirms our previous published ED(95) volume for mepivacaine 1% to block peripheral nerves. The volume of local anaesthetic has some influence on the sensory onset time.

Ultrasound-guided transversus abdominis plane block: description of a new technique and comparison with conventional systemic analgesia during laparoscopic cholecystectomy.

BACKGROUND: The transversus abdominis plane (TAP) block is usually performed by landmark-based methods. This prospective, randomized, and double-blinded study was designed to describe a method of ultrasound-guided TAP block and to evaluate the intra- and postoperative analgesic efficacy in patients undergoing laparoscopic cholecystectomy under general anaesthesia with or without TAP block. METHODS: Forty-two patients undergoing laparoscopic cholecystectomy were randomized to receive standard general anaesthetic either with (Group A, n=21) or without TAP block (Group B, n=21). Ultrasound-guided bilateral TAP block was performed with a high frequent linear ultrasound probe and an in-plane needle guidance technique with 15 ml bupivacaine 5 mg ml(-1) on each side. Intraoperative use of sufentanil and postoperative demand of morphine using a patient-controlled analgesia device were recorded. RESULTS: Ultrasonographic visualization of the relevant anatomy, detection of the shaft and tip of the needle, and the spread of local anaesthetic were possible in all cases where a TAP block was performed. Patients in Group A received significantly less [corrected] intraoperative sufentanil and postoperative morphine compared with those in Group B [mean (SD) 8.6 (3.5) vs 23.0 (4.8) microg, P<0.01, and 10.5 (7.7) vs 22.8 (4.3) mg, P<0.05]. CONCLUSIONS: Ultrasonographic guidance enables exact placement of the local anaesthetic for TAP blocks. In patients undergoing laparoscopic cholecystectomy under standard general anaesthetic, ultrasound-guided TAP block substantially reduced the perioperative opioid consumption.

Ultrasonographic guidance for sciatic and femoral nerve blocks in children.

BACKGROUND: Recent studies have shown that ultrasound guidance for paediatric regional anaesthesia can improve the quality of upper extremity and neuraxial blocks. We therefore investigated whether ultrasound guidance for sciatic and femoral nerve blocks prolongs sensory blockade in comparison with nerve stimulator guidance in children. METHODS: Forty-six children scheduled for surgery of one lower extremity were randomized to receive a sciatic and femoral nerve block under either ultrasound or nerve stimulator guidance. After induction of general anaesthesia, the blocks were performed using an ultrasound-guided multiple injection technique until the nerves were surrounded by levobupivacaine, or by nerve stimulator guidance using a predefined dose of 0.3 ml kg(-1) of levobupivacaine. An increase in heart rate of more than 15% of baseline during surgery defined a failed block. The duration of the block was determined from the injection of local anaesthetic to the time when the patient received the first postoperative analgesic. RESULTS: Two blocks in the nerve stimulator group failed. There were no failures in the ultrasound group. The duration of analgesia was longer in the ultrasound group mean (sd) 508 (178) vs 335 (169) min (P < 0.05). The volume of local anaesthetic in sciatic and femoral nerve blocks was reduced with ultrasound compared with nerve stimulator guidance [0.2 (0.06) vs 0.3 ml kg(-1) (P < 0.001) and 0.15 (0.04) vs 0.3 ml kg(-1) (P < 0.001), respectively]. CONCLUSIONS: Ultrasound guidance for sciatic and femoral nerve blocks in children increased the duration of sensory blockade in comparison with nerve stimulator guidance. Prolonged sensory blockade was achieved with smaller volumes of local anaesthetic when using ultrasound guidance.

Ultrasound-guided infrapatellar nerve block in human volunteers: description of a novel technique.

BACKGROUND: Despite the use of various treatment strategies arthroscopic knee surgery is still associated with clinically important postoperative pain. As the infrapatellar nerve (IPN) innervates vital anterior knee structures we decided to investigate the feasibility of a novel ultrasound-guided IPN block technique as a potential therapeutic option for out-patient arthroscopic knee surgery. METHODS: The IPN was blocked under ultrasonographic guidance in 10 adult volunteers using 5 ml of levobupivacaine 5 mg ml(-1). Success rate, time to maximum cutaneous distribution of the block, distribution of cutaneous analgesia and time until full recovery of cutaneous sensation was noted as was the incidence of concomitant blockade of the saphenous nerve (SN). RESULTS: The IPN was successfully blocked in 9/10 subjects. However, a varying degree of concomitant SN block was observed as part of all blocks. The time to maximum cutaneous distribution of the block was 8.4 (sd 3.6) min and the duration until complete recovery of cutaneous sensation was 27.5 (19.1) h. CONCLUSION: Reliable blockade of the IPN can be achieved with ultrasonographic guidance. Because of the very close anatomical relationship between the IPN and the SN it appears inevitable to also get a variable degree of concomitant SN block. The duration of the IPN block was in the majority of subjects greater than 16 h, a finding that may make this block useful for postoperative analgesia in out-patient arthroscopic surgery.

Ultrasonography-guided rectus sheath block in paediatric anaesthesia--a new approach to an old technique.

BACKGROUND: The purpose of this study was an anatomical and clinical evaluation of ultrasonography-guided rectus sheath blocks in children. METHOD: A total of 30 children were included in the sono-anatomical part of the study. The depth of the anterior and posterior rectus sheath was evaluated with a portable SonSite 180 plus ultrasound machine and a 5-10 MHz linear probe. In total, 20 consecutive children undergoing umbilical hernia repair were included in the clinical part of this study. After induction of general anaesthesia children received a rectus sheath block under real-time ultrasonographic guidance by placing 0.1 ml kg(-1) bilaterally in the space between the posterior aspect of the sheath and the rectus abdominis muscle. RESULTS: Ultrasonographic visualization of the posterior rectus sheath was possible in all children. The correlation between the depth of the posterior rectus sheath and weight (adjusted r(2)=0.175), height (adjusted r(2)=0.314) and body surface area (adjusted r(2)=0.241) was poor. The ultrasound-guided rectus sheath blockade provided sufficient analgesia in all children with no need for additional analgesia in the perioperative period. CONCLUSION: The bilateral placement of levobupivacaine 0.25% 0.1 ml kg(-1) in the space between the posterior aspect of the rectus sheath and the rectus abdominis muscle under real-time ultrasonographic guidance provides sufficient analgesia for umbilical hernia repair. The unpredictable depth of the posterior rectus sheath in children is a good argument for the use of ultrasonography in this regional anaesthetic technique in children.

Ultrasonographic-guided ilioinguinal/iliohypogastric nerve block in pediatric anesthesia: what is the optimal volume?

Recently, our study group demonstrated the usefulness of ultrasonographic guidance in ilioinguinal/iliohypogastric nerve blocks in children. As a consequence, we designed a follow-up study to evaluate the optimal volume of local anesthetic for this regional anesthetic technique. Using a modified step-up-step-down approach, with 10 children in each study group, a starting dose of 0.2 mL/kg of 0.25% levobupivacaine was administered to perform an ilioinguinal/iliohypogastric nerve block under ultrasonographic guidance. After each group of 10 patients, the results were analyzed, and if all blocks were successful, the volume of local anesthetic was decreased by 50%, and a further 10 patients were enrolled into the study. Failure to achieve a 100% success rate within a group subjected patients to an automatic increase of half the previous volume reduction to be used in the subsequent group. Using 0.2 and 0.1 mL/kg of 0.25% levobupivacaine, the success rate was 100%. With a volume of 0.05 mL/kg of 0.25% levobupivacaine, 4 of 10 children received additional analgesia because of an inadequate block. Therefore, according to the protocol, the amount was increased to 0.075 mL/kg of 0.25% levobupivacaine, where the success rate was again 100%. We conclude that ultrasonographic guidance for ilioinguinal/iliohypogastric nerve blocks in children allowed a reduction of the volume of local anesthetic to 0.075 mL/kg.

Epidural catheter placement in children: comparing a novel approach using ultrasound guidance and a standard loss-of-resistance technique.

BACKGROUND: We report a prospective, randomized study to evaluate ultrasound guidance for epidural catheter placement in children 0-6 yr of age. METHODS: Epidural catheters were placed at lumbar or thoracic cord levels in 64 children undergoing major surgery, using either ultrasonography or loss-of-resistance (LOR) for guidance. Using a 5-10 MHz linear ultrasound probe, the neuraxial structures were identified, the skin-epidural depth and epidural space was measured, the advancing epidural catheter visualized, and the spread of local anaesthetic verifying catheter position was confirmed. Epidural placement procedures were analysed for bone contacts and speed of execution. Children under 6 months were analysed separately. RESULTS: Epidural placement involved bone contacts in 17% of children in the ultrasound group and 71% of children in the LOR group (P<0.0001). Epidurals were executed more swiftly in the ultrasound group [162 (75) s vs 234 (138) s; P<0.01]. Children under 6 months revealed a 0.9 correlation between skin-epidural depth and body weight. CONCLUSIONS: Ultrasonography is a useful aid to verify epidural placement of local anaesthetic agents and epidural catheters in children. Advantages include a reduction in bone contacts, faster epidural placement, direct visualization of neuraxial structures and the spread of local anaesthetic inside the epidural space. Ultrasound guidance requires additional training and good manual skills, and should only be used once experience in ultrasound-guided techniques of regional anaesthesia has been acquired.

[Levobupivacaine for regional anesthesia. A systematic review]. / Levobupivacain in der Regionalanästhesie. Eine systematische Ubersicht der klinischen Anwendungen.

Levobupivacaine [S(-)bupivacaine], the levorotatory S-enantiomer of racemic bupivacaine, is commercially available in the U.S. and in most European countries. We performed a systematic review (MEDLINE database) and identified 88 articles on the clinical application of levobupivacaine in more than 3,000 patients. The use of levobupivacaine is described for epidural, caudal, and spinal anesthesia, for peripheral nerve blocks, for ophthalmic and dental anesthesia, for different pediatric indications and for intravenous regional anesthesia. In these regional techniques, levobupivacaine was used for all common indications in a wide range of clinical settings. Epidural levobupivacaine was combined with fentanyl, morphine, sufentanil, epinephrine, and clonidine, spinal levobupivacaine was combined with sufentanil, fentanyl, and epinephrine. In most studies, levobupivacaine was compared to bupivacaine and/or ropivacaine.

Ultrasonography for ilioinguinal/iliohypogastric nerve blocks in children.

BACKGROUND: The ilioinguinal/iliohypogastric nerve block is a popular regional anaesthetic technique for children undergoing inguinal surgery. The success rate is only 70-80% and complications may occur. A prospective randomized double-blinded study was designed to compare the use of ultrasonography with the conventional ilioinguinal/iliohypogastric nerve block technique. METHODS: One hundred children (age range, 1 month-8 years) scheduled for inguinal hernia repair, orchidopexy or hydrocele repair were included in the study. Following induction of general anaesthesia, the children received an ilioinguinal/iliohypogastric block performed either under ultrasound guidance using levobupivacaine 0.25% until both nerves were surrounded by the local anaesthetic or by the conventional 'fascial click' method using levobupivacaine 0.25% (0.3 ml kg(-1)). Additional intra- and postoperative analgesic requirements were recorded. RESULTS: Ultrasonographic visualization of the ilioinguinal/iliohypogastric nerves was possible in all cases. The amount of local anaesthetic used in the ultrasound group was significantly lower than in the 'fascial click' group (0.19 (SD 0.05) ml kg(-1) vs 0.3 ml kg(-1), P<0.0001). During the intraoperative period 4% of the children in the ultrasound group received additional analgesics compared with 26% in the fascial click group (P=0.004). Only three children (6%) in the ultrasound-guided group needed postoperative rectal acetaminophen compared with 20 children (40%) in the fascial click group (P<0.0001). CONCLUSIONS: Ultrasound-guided ilioinguinal/iliohypogastric nerve blocks can be achieved with significantly smaller volumes of local anaesthetics. The intra- and postoperative requirements for additional analgesia are significantly lower than with the conventional method.

Clonidine as an adjuvant to local anaesthetic axillary brachial plexus block: a randomized, controlled study.

BACKGROUND: We compared the effects of clonidine added to levobupivacaine and bupivacaine on axillary brachial plexus block as well as the effectiveness of levobupivacaine alone compared with bupivacaine alone. METHODS: In this prospective, randomized, controlled, double-blind trial, four groups of 20 patients each were investigated, using (i) 40 ml of levobupivacaine 0.5% plus 0.150 mg of clonidine, (ii) 40 ml of levobupivacaine 0.5% plus 1 ml of NaCl 0.9%, (iii) 40 ml of bupivacaine 0.5% plus 0.150 mg of clonidine, and (iv) 40 ml of bupivacaine 0.5% plus 1 ml of NaCl 0.9%, respectively. The onset of motor and sensory block and duration of sensory block were recorded. RESULTS: There was no significant difference in duration between groups, but a significantly higher variance (P<0.001) was found in the two groups with clonidine than in the two groups without. CONCLUSIONS: These findings suggest responder and non-responder behaviour is a result of the addition of clonidine.

Ultrasound guidance in regional anaesthesia.

The technology and clinical understanding of anatomical sonography has evolved greatly over the past decade. In the Department of Anaesthesia and Intensive Care Medicine at the Medical University of Vienna, ultrasonography has become a routine technique for regional anaesthetic nerve block. Recent studies have shown that direct visualization of the distribution of local anaesthetics with high-frequency probes can improve the quality and avoid the complications of upper/lower extremity nerve blocks and neuroaxial techniques. Ultrasound guidance enables the anaesthetist to secure an accurate needle position and to monitor the distribution of the local anaesthetic in real time. The advantages over conventional guidance techniques, such as nerve stimulation and loss-of-resistance procedures, are significant. This review introduces the reader to the theory and practice of ultrasound-guided anaesthetic techniques in adults and children. Considering their enormous potential, these techniques should have a role in the future training of anaesthetists.

Ultrasound guidance for infraclavicular brachial plexus anaesthesia in children.

Ultrasonography may offer significant advantages in regional anaesthesia of the upper and lower limbs. It is not known if the same advantages demonstrated in adults also apply to children. We therefore performed a prospective, randomised study comparing ultrasound visualisation to conventional nerve stimulation for infraclavicular brachial plexus anasesthesia in children. Forty children scheduled for arm and forearm surgery underwent infraclavicular brachial plexus blocks with ropivacaine 0.5 ml.kg(-1) guided by either nerve stimulation or ultrasound visualisation. Evaluated parameters included sensory block quality, sensory block distribution and motor block. All surgical procedures were performed under brachial plexus anaesthesia alone. Direct ultrasound visualisation was successful in all cases and was associated with significant improvements when compared with the use of nerve stimulation: lower visual analogue scores during puncture (p = 0.03), shorter mean (median) sensory onset times (9 (5-15) min vs. 15 (5-25) min, p < 0.001), longer sensory block durations (384 (280-480) min vs. 310 (210-420) min, p < 0.001), and better sensory and motor block scores 10 min after block insertion. Ultrasound visualisation offers faster sensory and motor responses and a longer duration of sensory blockade than nerve stimulation in children undergoing infraclavicular brachial plexus blocks. In addition, the pain associated with nerve stimulation due to muscle contractions at the time of insertion is eliminated.

[The choice of drugs for caudal anaesthesia in children. An overview]. / Kaudalanästhesie. Die Wahl der Medikamente für die Kaudalanästhesie bei Kindern.

Caudal anaesthesia is the most frequently used regional technique in paediatric anaesthesia. Caudal in combination with general anaesthesia is usually performed in healthy children (i.e. for herniotomy or hypospadias). Therefore every complication of this method is a catastrophe, even when the incidence of these complications is very low. Some of the documented complications of caudal anaesthesia in children are caused by the local anaesthetic solutions and/or by additives. Thus, the choice of substances for paediatric caudal blocks should minimize the risk associated with the substances used for this indication. Over the last decades the standard was bupivacaine but because of serious cardiovascular and central-nervous toxicity following inadvertent intravascular injection of bupivacaine during caudal puncture, the less toxic ropivacaine should be favoured for this indication. A huge number of clinical studies have proven the clinical effectiveness and safety of ropivacaine also for this indication. In addition, levobupivacaine, the L-enantiomere of bupivacaine, will also be an interesting local anaesthetic in the future for paediatric caudal anaesthesia. By using additives to local anaesthetics better analgesic properties should be obtained. Following an exact review of the literature, only clonidine and S(+)-ketamine are useful additives to local anaesthetics in paediatric caudal anaesthesia.

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

BACKGROUND: Brachial 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. METHODS: Forty paediatric trauma patients (ASA physical status I and II, age range 1-10 years) scheduled for forearm or hand surgery were randomly assigned to either axillary brachial plexus (ABP group) or LVIBP group blocks using 0.5 ml.kg(-1) ropivacaine 0.5%. Sensory blockade was evaluated by a visual analogue score and Vester-Andersen's criteria, the distribution of sensory and motor blockade was evaluated by a simplified pinprick test and motor tests. RESULTS: In the LVIBP group, Vester-Andersen's criteria were met by 100% of children, compared with 80% in the ABP group (P=0.035). Based on all assessable children, sensory blockade in the primary sensory regions of various nerves was significantly more effective in the LVIBP group (axillary: P < 0.0001; musculocutaneous: P=0.002; medial brachial cutaneous; P=0.008). Motor blockade was also significantly more effective (axillary: P < 0.0001; musculocutaneous: P=0.003). No major complications were observed in either group. DISCUSSION: We conclude that LVIBP blocks can be safely performed in children and that they add to the spectrum of sensory and motor blockade seen with the axillary approach.

[Ultrasound in local anaesthesia. Part II: ultrasound-guided blockade of peripheral nerve channels]. / Ultraschall in der Regionalanästhesie. Teil II: Ultraschallunterstützte Blockaden der peripheren Nervenbahnen.

Recent developments in blockade techniques are based on the possibilities offered by modern sonography. With high frequency linear probes, the smallest tissue structures, such as peripheral nerves, in areas close to the surface can be visualised. This is the prerequisite for ultrasound-guided blockade techniques which has now been established for available peripheral blockades. These techniques are basically far superior to all other assist methods of peripheral blockades, because they allow a success rate close to 100%, a short preparation time and a reduction in the use of local anaesthetic agents. Apart from these, one particularly important aspect is that they reduce the risks of local anaesthesia procedures by direct imaging of neighbouring anatomical structures. In this article the theoretical basis of ultrasound techniques and their practical use in local anaesthesia will be presented.

[Ultrasound in local anaesthesia. Part I: technical developments and background]. / Ultraschall in der RegionalanästhesieTeil I: Technische Entwicklungen und Grundlagen.

The 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."

Ultrasonographic assessment of topographic anatomy in volunteers suggests a modification of the infraclavicular vertical brachial plexus block.

BACKGROUND: The infraclavicular vertical brachial plexus block, first described by Kilka and coworkers, offers a more proximal spread of anaesthesia for the upper extremity than the classic axillary approach. In this technique, the puncture site is defined as lying at the exact centre of an infraclavicular line (k) between the jugular fossa and the ventral process of the acromion. Our study was designed to determine whether the point so defined (P) corresponds with the optimal puncture site determined sonographically (S) and to develop an improved prediction model. METHOD: High-resolution ultrasonography was carried out in 59 volunteers to visualize the plexus. Sonography-derived distances and morphometric measurements were used to test accuracy and calculate multiple regressions. RESULTS: We found a clear trend towards a more lateral puncture site. In women, S was significantly (P<0.001) lateral (8 mm) to P. The overall accuracy of the infraclavicular vertical brachial plexus block technique was not sufficient to predict the optimal puncture site reliably. Our resulting improved prediction model is valid for both sexes and is based not just on the centre point but on the absolute length of k (22-22.5 cm). We found that for every 1 cm decrease in k the optimal puncture site moved 2 mm laterally from the exact centre of k, and for every 1 cm increase in k it moved 2 mm medially. CONCLUSIONS: The suggested modification should help to increase the success rate of the infraclavicular vertical brachial plexus block while decreasing the rate of potentially severe complications, although individual ultrasonographic guidance is to be recommended whenever possible.

First experience with fiberoptically directed wire-guided endobronchial blockade in severe pulmonary bleeding in an emergency setting.

We report the first use of a new wire-guided endobronchial blocker in a critical respiratory situation caused by localized pulmonary bleeding. During emergency management, it became increasingly difficult to ventilate a multiple-trauma patient with a conventional single-lumen tube because of massive bleeding through the bronchus of the left lower lobe. Using the Arndt endobronchial blocker set (William Cook Europe A/S; Bjaeverskor, Denmark), we were able to prevent the spread of hemorrhaging and achieved effective ventilation and marked improvement in gas exchange. This new device allows the effective blockade of an isolated lobe under direct bronchoscopy to buy time for further intervention.

A study of the paravertebral anatomy for ultrasound-guided posterior lumbar plexus block.

IMPLICATIONS: We investigated the feasibility of posterior paravertebral sonography as a basis for ultrasound-guided posterior lumbar plexus blockades. Posterior paravertebral sonography proved to be a reliable as well as accurate imaging procedure for visualization of the lumbar paravertebral region except the lumbar plexus.