[Show abstract][Hide abstract] ABSTRACT: The use of certain peripheral nerve blocks in paediatric patients is gaining increasing popularity, although distinctive characteristics of the juvenile anatomy, psychological barriers, time constraints on block placement, and risks of neurotoxic and cardio toxic side effects are still mentioned. However, newer agents like Ropivacaine and Levobupivacaine seem to offer excellent alternatives to Bupivacaine and Lidocaine, especially for use in paediatric patients.
We evaluated Ropivacaine 0.5% and Lidocaine 1.0% using axillary plexus blockade as a single-shot technique in 50 children in the age group of 2 to 10 years and undergoing short upper limb surgery. The primary objectives were to compare onset time, duration and quality of block and the incidence of breakthrough pain.
Onset time was longer in the Ropivacaine group (15.4 minutes) than in the Lidocaine group (8.2 minutes). The duration of the effect was greater in patients in the Ropivacaine group (337 minutes) than in the Lidocaine group (137 minutes). Duration appeared to vary with patient's age but this effect was not statistically significant.
Axillary plexus anaesthesia provides satisfactory perioperative pain relief in infants undergoing short-trauma surgery. Apart from its safety, these results underline that Ropivacaine 0.5% can be recommended for axillary brachial plexus block in children.
No preview · Article · May 2010 · African Journal of Paediatric Surgery
[Show abstract][Hide abstract] ABSTRACT: 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.
[Show abstract][Hide abstract] ABSTRACT: Nerve blocks using local anesthetics are widely used. High volumes are usually injected, which may predispose patients to associated adverse events. Introduction of ultrasound guidance facilitates the reduction of volume, but the minimal effective volume is unknown. In this study, we estimated the 50% effective dose (ED50) and 95% effective dose (ED95) volume of 1% mepivacaine relative to the cross-sectional area of the nerve for an adequate sensory block.
To reduce the number of healthy volunteers, we used a volume reduction protocol using the up-and-down procedure according to the Dixon average method. The ulnar nerve was scanned at the proximal forearm, and the cross-sectional area was measured by ultrasound. In the first volunteer, a volume of 0.4 mL/mm of nerve cross-sectional area was injected under ultrasound guidance in close proximity to and around the nerve using a multiple injection technique. The volume in the next volunteer was reduced by 0.04 mL/mm in case of complete blockade and augmented by the same amount in case of incomplete sensory blockade within 20 mins. After 3 up-and-down cycles, ED50 and ED95 were estimated. Volunteers and physicians performing the block were blinded to the volume used.
A total 17 of volunteers were investigated. The ED50 volume was 0.08 mL/mm (SD, 0.01 mL/mm), and the ED95 volume was 0.11 mL/mm (SD, 0.03 mL/mm). The mean cross-sectional area of the nerves was 6.2 mm (1.0 mm).
Based on the ultrasound measured cross-sectional area and using ultrasound guidance, a mean volume of 0.7 mL represents the ED95 dose of 1% mepivacaine to block the ulnar nerve at the proximal forearm.
Full-text · Article · May 2009 · Regional anesthesia and pain medicine
[Show abstract][Hide abstract] ABSTRACT: Ilioinguinal-iliohypogastric nerve blockade (INB) is associated with high plasma concentrations of local anesthetics (LAs) in children. Ultrasonographic guidance enables exact anatomical administration of LA, which may alter plasma levels. Accordingly, we compared plasma levels of ropivacaine after ultrasonographic versus landmark-based INB.
After induction of general anesthesia, 66 children (8-84 mo) scheduled for inguinal hernia repair received INB with 0.25 mL/kg of ropivacaine 0.5% (1.25 mg/kg) either by a landmark-based (n = 31) or by an ultrasound-guided technique (n = 35). Ropivacaine plasma levels were measured before (0) and 5, 10, 20, and 30 min after the LA injection, using high-performance liquid chromatography. Maximum plasma concentrations (C(max)), time to C(max) (t(max)), the absorption rate constant (k(a)), the speed of rise of the plasma concentration at Time 0 (dC(0)/dt), and area under the curve value (AUC) were determined.
The ultrasound-guided technique resulted in higher C(max) (sd), k(a), dC(0)/dt, and AUC values and shorter t(max) compared with the landmark-based technique (C(max): 1.78 [0.62] vs 1.23 [0.70] microg/mL, P < 0.01; k(a): 14.4 [10.7] vs 11.7 [11.4] h(-1), P < 0.05; dC(0)/dt: 0.26 [0.12] vs 0.15 [0.03] microg/mL . min, P < 0.01; AUC: 42.4 [15.9] vs 27.2 [18.1] microg . 30 min/mL, P < 0.001; t(max): 20.4 [8.6] vs 25.3 [7.6] min, P < 0.05).
The pharmacokinetic data indicate faster absorption and higher maximal plasma concentration of LA when ultrasound was used as a guidance technique for INB compared with the landmark-based technique. Thus, a reduction of the volume of LA should be considered when using an ultrasound-guided technique for INB.
No preview · Article · May 2009 · Anesthesia and analgesia
[Show abstract][Hide abstract] ABSTRACT: 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.
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.
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].
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.
Full-text · Article · Apr 2009 · BJA British Journal of Anaesthesia
[Show abstract][Hide abstract] ABSTRACT: The use of ultrasonography in regional anesthetic blocks has rapidly evolved over the past few years. It has been speculated that ultrasound guidance might increase success rates and reduce complications. The aim of our study is to compare the success rate and quality of interscalene brachial plexus blocks performed either with direct ultrasound visualization or with the aid of nerve stimulation to guide needle placement.
A total of 160 patients (American Society of Anesthesiologists physical status classification I-III) scheduled for trauma-related upper arm surgery were included in this randomized study and grouped according to the guidance method used to deliver 20 mL of ropivacaine 0.75% for interscalene brachial plexus blockade. In the ultrasound group (n = 80), the brachial plexus was visualized with a linear 5 to 10 MHz probe and the spread of the local anesthetic was assessed. In the nerve stimulation group (n = 80), the roots of the brachial plexus were located using a nerve stimulator (0.5 mA, 2 Hz, and 0.1 millisecond bandwidth). The postblock neurologic assessment was performed by a blinded investigator.
Sensory and motor blockade parameters were recorded at different points of time. Surgical anesthesia was achieved in 99% of patients in the ultrasound vs 91% of patients in the nerve stimulation group (P < .01). Sensory, motor, and extent of blockade was significantly better in the ultrasound group when compared with the nerve stimulation group.
The use of ultrasound to guide needle placement and monitor the spread of local anesthetic improves the success rate of interscalene brachial plexus block.
No preview · Article · May 2008 · Regional anesthesia and pain medicine
[Show abstract][Hide abstract] ABSTRACT: Ultrasonographic observation of peripheral nerve blocks enables direct visualization of the spread of local anesthetic around the targeted nerves. Similarly, ultrasonography may be used to determine the site of local anesthetic placement when landmark-based techniques are used. We performed a study to determine the actual location of local anesthetic when ilioinguinal/iliohypogastric nerve blocks are performed using landmark-based techniques in children in an attempt to explain a failed block.
After induction of general anesthesia (1 minimum alveolar anesthetic concentration halothane and laryngeal mask airway), 62 children scheduled for inguinal surgery received an ilioinguinal/iliohypogastric nerve block based on standard anatomical landmarks. Ultrasonography was then used to determine the actual location of local anesthetic placement. The anesthesiologist performing the block was blinded to the ultrasonographic investigation. Successful blocks were recorded either when the local anesthetic surrounded the nerves or were based on clinical signs after skin incision.
In 14% of the blocks, the local anesthetic was administered correctly around the nerves resulting in successful blocks. In the remaining 86%, the local anesthetic was administered in adjacent anatomical structures (iliac muscle 18%, transverse abdominal muscle 26%, internal oblique abdominal muscle 29%, external oblique abdominal muscle 9%, subcutaneous 2%, and peritoneum 2%), and 45% of these blocks failed.
Accurate placement of local anesthetic around the ilioinguinal/iliohypogastric nerves in children is seldom possible when landmark-based techniques are used. In the majority of patients, the local anesthetic was inaccurately placed in adjacent anatomical structures with unpredictable block results.
Full-text · Article · Feb 2008 · Anesthesia and analgesia
[Show abstract][Hide abstract] ABSTRACT: 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.
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.
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].
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.
Preview · Article · Jun 2007 · BJA British Journal of Anaesthesia
[Show abstract][Hide abstract] ABSTRACT: We report the first prospective sonoanatomic study in neonates with the aim to perform ultrasonographic-guided epidural catheter placement in this age group.
One hundred forty-five neonates with a body weight < or =4 kg (0.53-4 kg) were included in this prospective study. The study was divided into 3 consecutive parts. In the first part, the neuraxial sonoanatomy of 60 neonates was evaluated. In the second part, 50 neonates scheduled for major abdominal surgery were enrolled. In this part, the depth of the ligamentum flavum measured with ultrasound was matched up to the depth evaluated clinically with the loss-of-resistance technique. In the third part, ultrasonographic epidural catheter placement was performed in 35 neonates weighing between 620 g and 4 kg.
The ligamentum flavum, the dura mater, and the termination of the spinal cord could be identified in all patients. The first part showed a good correlation between body weight and depth of the ligamentum flavum. The median termination of the spinal cord corresponded to vertebral level L2. The second part confirmed a good correlation between depth of the ligamentum flavum evaluated clinically and the depth predicted with ultrasound. Finally, real-time ultrasound-guided epidural placement was possible in all 35 neonates.
Ultrasound examination of the spinal cord anatomy provides valuable information for epidural catheter placement in neonates. Ultrasonography enables a real-time identification of the tip of the needle within the epidural space and a visualization of the spread of local anesthetic in these patients.
Full-text · Article · Jan 2007 · Regional Anesthesia and Pain Medicine
[Show abstract][Hide abstract] ABSTRACT: 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.
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).
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.
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.
Full-text · Article · Dec 2006 · BJA British Journal of Anaesthesia
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was an anatomical and clinical evaluation of ultrasonography-guided rectus sheath blocks in children.
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.
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.
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.
Preview · Article · Sep 2006 · BJA British Journal of Anaesthesia
[Show abstract][Hide abstract] ABSTRACT: We report a prospective, randomized study to evaluate ultrasound guidance for epidural catheter placement in children 0-6 yr of age.
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.
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.
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.
Full-text · Article · Aug 2006 · BJA British Journal of Anaesthesia
[Show abstract][Hide abstract] ABSTRACT: 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.
Full-text · Article · Jul 2006 · Anesthesia and analgesia