Ultrasound-guided peripheral nerve blockade of the upper extremity. Curr Opin Anaesthesiol. 2012;25:253-259. [PMID: 22246462 DOI: 10.1097/aco.0b013e32835069c2]

Low-Volume Targeted Interscalene Brachial Plexus Block in the Emergency Department as a Safer Alternative for Pain Control for Glenohumeral Reduction: A Case Series

BACKGROUND

Acute glenohumeral dislocation is a common emergency department (ED) presentation, however, pain control to facilitate reduction in these patients can be challenging. Although both procedural sedation and peripheral nerve blocks can provide effective analgesia, both also carry risks. Specifically, the interscalene brachial plexus block carries risk of ipsilateral hemidiaphragmatic paralysis due to inadvertent phrenic nerve involvement. There are techniques, however, that the emergency clinician can utilize to reduce these risks and optimize the interscalene brachial plexus block for specific pathologies such as glenohumeral dislocation.

CASE SERIES

We report three cases of patients who presented to the ED with acute anterior glenohumeral dislocation. Two of the patients had a history of pulmonary disease. In all three cases, targeted low-volume interscalene nerve blocks were performed and combined with systemic analgesia to facilitate successful closed glenohumeral reduction and reduce the risk of diaphragm paralysis. All 3 patients were monitored after the procedure and discharged from the ED. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Contrary to anesthesiologists who often seek to obtain dense surgical blocks, the goal of the emergency clinician should be to tailor blocks for specific procedures, patients, and pathologies. The emergency clinician can optimize the interscalene brachial plexus block for glenohumeral dislocation by using a low volume (5-10 mL) of anesthetic targeted to specific nerve roots (C5 and C6) to provide effective analgesia and reduce the risk diaphragm involvement.

Digit Replantation under Wide-Awake Local Anesthesia

BACKGROUND

Digit replantation under wide-awake local anesthesia is a challenging method, and there are only a few works of literature on this procedure. This article describes the authors' clinical experience in finger replantation under wide-awake local anesthesia compared to general anesthesia.

METHODS

Fifty-one patients who received single finger replantation after initial sharp amputation were included in the study, of whom 16 received wide-awake local anesthesia and 35 general anesthesia treatment. The indications for wide-awake local anesthesia were sharp amputation injury, estimated operation time less than 3 hours, and cooperative patients. The wide-awake local anesthesia was performed with 1% or 2% lidocaine infiltrated at the volar midpoint of the metacarpophalangeal joint of the affected digit without sedation medications. Demographic data included surgical outcome, waiting time, operation time, and hospital stay.

RESULTS

A total of 51 consecutive patients were included in this study. There were significantly shorter waiting times and operation times in the wide-awake local anesthesia group. The other parameters showed no significant differences. The overall success rate was 76.47 percent, with a mean overall operation time of 207 minutes.

CONCLUSIONS

In selected patients, finger replantation can be successfully performed under wide-awake local anesthesia, which has lower anesthesia risk and fewer medical expenses than general anesthesia. The method is feasible for single-digit replantation. Therefore, the finger replantation under wide-awake local anesthesia is a practicable alternative to general anesthesia.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Assessment of Duplex ultrasound carried out by the vascular surgeon after locoregional anesthesia for preferred arteriovenous fistula access

OBJECTIVES

Preoperative vascular mapping by duplex ultrasound is required in construction of an arteriovenous fistula for hemodialysis (AVF). Due to venous vasospasm in cool temperatures and variability of the dialysis patient's blood volume, the conditions for performing this examination may be less than ideal. However, local regional anesthesia (LRA) resulting in vasodilation of the limb, can allow the use of veins considered to be of insufficient caliber during preoperative ultrasound mapping. The aim of this study was to assess the functionality of AVF when duplex ultrasound is performed by the surgeon following LRA. These results were compared with those from the preceding year, during which preoperative duplex ultrasound had been performed without LRA by vascular specialists, (Clinical Trial registration number: NCT04978155).

MATERIALS AND METHODS

This is a prospective study of all the patients having received AVF after systematic immediate preoperative ultrasound (US) under LRA (US-LRA group) in 2020. The initial surgical programming based on the Silva criteria was reported by a vascular medicine specialist. The change of AVF strategy following US-LRA was reported together with AVF usability and patency and compared to the results of the control group, in which AVF had been performed in 2019 without US-LRA.

RESULTS

Ninety patients were included in the US-LRA group and 93 in the control group. Modified surgical planning was observed in 38% of cases (35/90) in the US-LRA group including more distal AVF in 28% of patients (26/90) and alternative target vein in 6.6% (6/90). AVF usability at 6 weeks was 80% (72/90) in the US-LRA group and 51.6% (48/93) in the control group (p<.001). Median follow-up was 12 months [IQR:9-15] in the US-LRA group and 13 months [IQR:9-18] in the control group. Primary patency at 6, 12, 18 months was significantly better in the US-LRA group (73.6% vs. 57.4%, 54.4% vs. 40.2%, 31.3% vs. 28.2%, respectively, p<.001). Assisted patency and secondary patency were comparable in the two groups.

CONCLUSION

This study showed the benefit of having the surgeon perform US-LRA before starting the procedure, thereby allowing for more distal AVF, better usability and patency.

Supraclavicular vs. Infraclavicular Brachial Plexus Nerve Blocks: Clinical, Pharmacological, and Anatomical Considerations

: Peripheral nerve blocks (PNB) have become standard of care for enhanced recovery pathways after surgery. For brachial plexus delivery of anesthesia, both supraclavicular (SC) and infraclavicular (IC) approaches have been shown to require less supplemental anesthesia, are performed more rapidly, have quicker onset time, and have lower rates of complications than other approaches (axillary, interscalene, etc.). Ultrasound-guidance is commonly utilized to improve outcomes, limit the need for deep sedation or general anesthesia, and reduce procedural complications. Given the SC and IC approaches are the most common approaches for brachial plexus blocks, the differences between the two have been critically evaluated in the present manuscript. Various studies have demonstrated slight favorability towards the IC approach from the standpoint of complications and safety. Two prospective RCTs found a higher incidence of complications in the SC approach – particularly Horner syndrome. The IC method appears to support a greater block distribution as well. Overall, both SC and IC brachial plexus nerve block approaches are the most effective and safe approaches, particularly under ultrasound-guidance. Given the success of the supraclavicular and infraclavicular blocks, these techniques are an important skill set for the anesthesiologist for intraoperative anesthesia and postoperative analgesia.

Triple Monitoring May Avoid Intraneural Injection during Interscalene Brachial Plexus Block for Arthroscopic Shoulder Surgery: A Prospective Preliminary Study

Nerve injury is a feared complication of peripheral nerve blockade. The aim of this study was to test the effectiveness of a triple monitoring (TM), i.e., a combination of ultrasound (US), nerve stimulation (NS) and opening injection pressure (OIP) during interscalene brachial plexus block (IBPB) for surgery of the shoulder. Sixty patients undergoing IBPB for shoulder arthroscopy received TM. BSmart^®, an inline injection device connected to a 10 mL syringe, was used to detect OIP during IBPB. Nerve stimulation was set to 0.5 mA to rule out any motor response, and if OIP was below 15 PSI, 10 mL of local anaesthetic was injected under US guidance between the C5 and C6 roots. The main outcome was the ability of TM to detect a needle–nerve contact. Other outcomes including the duration of IBPB; pain during injection; postoperative neurologic dysfunction. Triple monitoring revealed needle–nerve contact in 33 patients (55%). In 18 patients, NS evoked motor responses despite first control with US; in a further 15 patients, BSmart^® detected an OIP higher than 15 PSI, despite the absence of motor response to NS. Mean duration of IBPB was 67.2 ± 5.3 seconds; neither pain during injection nor postoperative neurologic dysfunctions were detected. Clinical follow up excluded the presence of postoperative neuropathies. Triple monitoring showed to be a useful and feasible tool while performing IBPB for arthroscopic shoulder surgery. Future studies will be needed to confirm our findings.

Analgesic Effect of the Topical Use of Dexamethasone in Ultrasound-Guided Axillary Brachial Plexus Blockade: A Prospective, Randomized, Double-Blind, Placebo-Controlled Study

Introduction

Increasing the duration of regional anesthesia in orthopedic surgery is of vital importance, as it prolongs postoperative analgesia, allowing faster rehabilitation of patients. Dexamethasone has been found to extend the block duration in animal and human studies. The aim of this study is the assessment of the effect of the addition of dexamethasone to ropivacaine on the onset and duration of axillary brachial plexus block, along with the intensity of postoperative pain.

Methods

Forty patients undergoing below-elbow surgery under ultrasound-guided axillary brachial plexus block were randomly allocated to receive either 30 mL ropivacaine 0.75% with 2 mL of saline (Group A, n = 20) or 30 mL ropivacaine 0.75% with 2 mL of dexamethasone (4 mg) (Group B, n = 20). Sensory and motor blockade were assessed, with the use of the pinprick test and the modified Bromage scale, at five, 10, 15, and 20 min after the block. The duration of analgesia, intensity of postoperative pain, postoperative opioid consumption, overall satisfaction, and perioperative complications were compared between the two groups.

Results

We found no difference at the mean onset time of the sensory and motor block between the two groups. The mean duration of postoperative analgesia was three hours higher in the dexamethasone group (15.85 ± 4.82 versus 11.75 ± 6.81, p-value = 0.035). Pain intensity was lower in the dexamethasone group, at six and 12 hours after surgery (3.45 ± 1.79 versus 4.65 ± 1.79, p-value = 0.040). Postoperative opioid consumption, patient overall satisfaction, and perioperative complications were not significantly different between groups.

Conclusions

Dexamethasone prolongs the duration of ropivacaine in an axillary brachial plexus block and decreases postoperative pain in patients subjected to below-elbow surgery.

Ultrasound-guided perineural injection for nerve blockade: Does a single-sided injection produce circumferential nerve coverage?

PURPOSE

Our current clinical technique for sonographic-guided perineural injection consists of two-sided perineural needle placement to obtain circumferential distribution of the injectate. This study aimed to determine if a single-side needle position will produce circumferential nerve coverage.

METHODS

Fresh-frozen cadaveric specimens were used for this study. In six upper extremities, a needle was positioned along the deep surface of median, radial, and ulnar nerves in the carpal tunnel, radial tunnel, and cubital tunnel, respectively, and 2 ml of contrast was injected for each nerve. In three pelvic specimens, a needle was positioned deep to the sciatic nerves bilaterally, and 5 ml of contrast was injected. An additional four median nerve injections were performed using superficial surface needle position. The specimens then underwent CT scanning to assess the distribution of the perineural contrast medium.

RESULTS

One hundred percent of the radial, ulnar, and sciatic nerves demonstrated circumferential distribution on CT. Only 50% of the median nerve injections with the needle placed deep to the nerve produced circumferential coverage, whereas 100% of median nerves injected with the needle between the nerve and retinaculum demonstrated circumferential coverage. The average length of spread of perineural injectate was 11.6 cm in the upper extremity and 10.3 cm for the sciatic nerves.

CONCLUSIONS

Using clinical volumes of fluid, needle positioning at the deep surface of upper extremity and sciatic nerves was sufficient to produce circumferential coating of the nerve, except in the carpal tunnel, where placement of the needle between the nerve and flexor retinaculum is recommended. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:465-469, 2016.

Peripheral nerve blocks on the upper extremity: Technique of landmark-based and ultrasound-guided approaches

The German Society of Anaesthesiology and Intensive Care Medicine (Deutsche Gesellschaft für Anästhesiologie und Intensivmedizin, DGAI) established an expert panel to develop preliminary recommendations for the application of peripheral nerve blocks on the upper extremity. The present recommendations state in different variations how ultrasound and/or electrical nerve stimulation guided nerve blocks should be performed. The description of each procedure is rather a recommendation than a guideline. The anaesthesiologist should select the variation of block which provides the highest grade of safety according to his individual opportunities. The first section comprises recommendations regarding dosages of local anaesthetics, general indications and contraindications for peripheral nerve blocks and informations about complications. In the following sections most common blocks techniques on the upper extremity are described.

Feasibility, efficacy, and safety of ultrasound-guided axillary plexus blockade in pediatric patients with epidermolysis bullosa dystrophica

BACKGROUND

In patients suffering from epidermolysis bullosa dystrophica (DEB), the most severe form of epidermolysis bullosa, trauma or friction cause separation of the skin from underlying tissue with consecutive painful blisters, scarifications, contractures, and pseudosyndactyly. To retain functionality of the hands surgical procedures are necessary. Anesthesia is challenging as difficult airways make general anesthesia risky. Regional anesthesia is considered controversial in patients with EB as accidental subcutaneous injections can cause severe blisters. As ultrasound-guided procedures became standard of care this might have changed however.

AIM

In this case series, we describe feasibility, efficacy, and safety of ultrasound-guided plexus axillaris block in DEB patients undergoing hand surgery.

METHOD

We performed a retrospective analysis of the charts of all children with DEB undergoing hand surgery under plexus axillaris block and sedation between 2009 and 2013 in our institution.

RESULTS

Nineteen procedures in nine children were performed. Induction of anesthesia (securing monitoring, sedation, plexus block) took a mean time of 34 min. Perioperative analgesia was adequate in all procedures. No complications such as airway incidents, conversion to general anesthesia, movement during surgery, incomplete block, or formation of new blisters were seen.

CONCLUSION

Ultrasound-guided plexus axillaris block in DEB patients undergoing hand surgery in our institution has been feasible, effective, and safe.

COMPARISON OF ULTRASOUND-GUIDED VS. STANDARD LANDMARK TECHNIQUES FOR TRAINING NOVICE OPERATORS IN PLACING NEEDLES INTO THE LUMBAR SUBARACHNOID SPACE OF CANINE CADAVERS

The standard technique for placing a needle into the canine lumbar subarachnoid space is primarily based on palpation of anatomic landmarks and use of probing movements of the needle, however, this technique can be challenging for novice operators. The aim of the current observational, prospective, ex vivo, feasibility study was to compare ultrasound-guided vs. standard anatomic landmark approaches for novices performing needle placement into the lumbar subarachnoid space using dog cadavers. Eight experienced operators validated the canine cadaver model as usable for training landmark and ultrasound-guided needle placement into the lumbar subarachnoid space based on realistic anatomy and tissue consistency. With informed consent, 67 final year veterinary students were prospectively enrolled in the study. Students had no prior experience in needle placement into the lumbar subarachnoid space or use of ultrasound. Each student received a short theoretical training about each technique before the trial and then attempted blind landmark-guided and ultrasound-guided techniques on randomized canine cadavers. After having performed both procedures, the operators completed a self-evaluation questionnaire about their performance and self-confidence. Total success rates for students were 48% and 77% for the landmark- and ultrasound-guided techniques, respectively. Ultrasound guidance significantly increased total success rate when compared to the landmark-guided technique and significantly reduced the number of attempts. With ultrasound guidance self-confidence was improved, without bringing any significant change in duration of the needle placement procedure. Findings indicated that use of ultrasound guidance and cadavers are feasible methods for training novice operators in needle placement into the canine lumbar subarachnoid space.

Lack of Sex Difference in Minimum Local Analgesic Concentration of Ropivacaine for Ultrasound-Guided Supraclavicular Brachial Plexus Block

Background

Sex differences, which may be an important variable for determining anesthetic requirements, have not been well investigated in the aspect of local anesthetic. This investigation aimed to compare the minimum local analgesic concentration (MLAC) of ropivacaine for ultrasound-guided supraclavicular brachial plexus block (US-SCB) between men and women.

Material/Method

Patients aged 18–45 years undergoing elective forearm, wrist, or hand surgeries under US-SCB were divided into 2 groups according to sex. The initial concentration was 0.375% ropivacaine 20 mL and the concentration for the next patient was determined by the up-down technique at 0.025% intervals. Success was defined as the absence of any pain in response to a pinprick in the region of all 4 terminal nerves and the skin incision within 45 min. The primary outcome was the MLAC of ropivacaine, which was estimated by the Dixon and Massey method. The analgesia duration, which was defined as the time from the end of the US-SCB injection to the time of feeling discomfort and need for additional analgesics, was observed for each patient.

Results

The MLAC of ropivacaine 20 mL for US-SCB was 0.2675% (95% confidence interval [CI], 0.2512–0.2838%) in men and 0.2675% (95% CI, 0.2524–0.2826%) in women. There was no significant difference in MLAC or the analgesia duration between the 2 groups (P>0.05).

Conclusions

We found no significant sex-related differences in MLAC or analgesia duration of ropivacaine for US-SCB.

Comparative evaluation of adding different opiates (morphine, meperidine, buprenorphine, or fentanyl) to lidocaine in duration and quality of axillary brachial plexus block

Background:

There is no agreement about the effect of adding opioids to local anesthetics in peripheral nerve blocks. The aim of this study was to investigate the effect of adding different opioids with equipotent doses of lidocaine in axillary brachial plexus block using ultrasonography and nerve locator guidance.

Materials and Methods:

In a prospective, randomized, double-blind clinical trial study, 72 adult patients aged 18–65 years old scheduled for orthopedic surgery of the forearm and hand with axillary brachial plexus block were selected and randomly allocated to four groups. Meperidine (pethidine), buprenorphine, morphine, and fentanyl with equipotent doses were added in 40cc of 1% lidocaine in P, B, M, and F groups, respectively. The onset and duration of sensory and motor blocks, severity of patients’ pain, duration of analgesia, hemodynamic and respiratory parameters, and adverse events (such as nausea and pruritus) during perioperative period were recorded.

Results:

The onset time for the sensory block was similar in the four groups. The onset time for the motor block was significantly faster in morphine and pethidine groups (P = 0.006). The duration of sensory and motor blocks was not statistically different among the four groups. The quality of motor blockade was complete in 100% of patients receiving pethidine or morphine and 77.8% of patients receiving buprenorphine or fentanyl (P = 0.021).

Conclusion:

In the upper extremity surgeries performed under axillary brachial plexus block addition of morphine or pethidine to lidocaine may be superior to other opioids (i.e. fentanyl and buprenorphine) due to better quality and quantity of motor blockade and faster onset of the block.

An evaluation of brachial plexus block using a nerve stimulator versus ultrasound guidance: A randomized controlled trial

Background and Aims:

This study was carried out to evaluate the difference in efficacy, safety, and complications of performing brachial plexus nerve blocks by using a nerve locator when compared to ultrasound (US) guidance.

Material and Methods:

A total of 102 patients undergoing upper limb surgery under supraclavicular brachial plexus blocks were randomly divided into two groups, one with US and the other with nerve stimulator (NS). In Group US, “Titan” Portable US Machine, Sonosite, Inc. Kensington, UK with a 9.0 MHz probe was used to visualize the brachial plexus and 40 ml of 0.25% bupivacaine solution was deposited around the brachial plexus in a graded manner. In Group (NS), the needle was inserted 1-1.5 cm above mid-point of clavicle. Once hand or wrist motion was detected at a current intensity of less than 0.4 mA 40 ml of 0.25% bupivacaine was administered. Onset of sensory and motor block of radial, ulnar and median nerves was recorded at 5-min intervals for 30-min. Block execution time, duration of block (time to first analgesic), inadvertent vascular puncture, and neurological complications were taken as the secondary outcome variables.

Results:

About 90% patients in US group and 73.1% in NS group, had successful blocks P = 0.028. The onset of block was faster in the Group US as compared to Group NS and this difference was significant (P 0.007) only in the radial nerve territory. The mean duration of the block was longer in Group US, 286.22 ± 42.339 compared to 204.37 ± 28.54-min in Group NS (P < 0.05). Accidental vascular punctures occurred in 7 patients in the NS group and only 1 patient in the US group.

Conclusion:

Ultrasound guidance for supraclavicular brachial plexus blockade provides a block that is faster in onset, has a better quality and lasts longer when compared with an equal dose delivered by conventional means.

Ultrasound-guided femoral and sciatic nerve blocks combined with sedoanalgesia versus spinal anesthesia in total knee arthroplasty

Background

Although regional anesthesia is the first choice for patients undergoing total knee arthroplasty (TKA), it may not be effective and the risk of complications is greater in patients who are obese or who have spinal deformities. We compared the success of ultrasound-guided femoral and sciatic nerve blocks with sedoanalgesia versus spinal anesthesia in unilateral TKA patients in whom spinal anesthesia was difficult.

Methods

We enrolled 30 patients; 15 for whom spinal anesthesia was expected to be difficult were classified as the block group, and 15 received spinal anesthesia. Regional anesthesia was achieved with bupivacaine 62.5 mg and prilocaine 250 mg to the sciatic nerve, and bupivacaine 37.5 mg and prilocaine 150 mg to the femoral nerve. Bupivacaine 20 mg was administered to induce spinal anesthesia. Hemodynamic parameters, pain and sedation scores, and surgical and patient satisfaction were compared.

Results

A sufficient block could not be obtained in three patients in the block group. The arterial pressure was significantly lower in the spinal group (P < 0.001), and the incidence of nausea was higher (P = 0.017) in this group. Saturation and patient satisfaction were lower in the block group (P < 0.028), while the numerical pain score (P < 0.046) and the Ramsay sedation score were higher (P = 0.007).

Conclusions

Ultrasound-guided sciatic and femoral nerve blocks combined with sedoanalgesia were an alternative anesthesia method in selected TKA patients.

Perioperative pain control after total knee arthroplasty: An evidence based review of the role of peripheral nerve blocks

Over the last decades, the number of total knee arthroplasty procedures performed in the United States has been increasing dramatically. This very successful intervention, however, is associated with significant postoperative pain, and adequate postoperative analgesia is mandatory in order to allow for successful rehabilitation and recovery. The use of regional anesthesia and peripheral nerve blocks has facilitated and improved this goal. Many different approaches and techniques for peripheral nerve blockades, either landmark or, more recently, ultrasound guided have been described over the last decades. This includes but is not restricted to techniques discussed in this review. The introduction of ultrasound has improved many approaches to peripheral nerves either in success rate and/or time to block. Moreover, ultrasound has enhanced the safety of peripheral nerve blocks due to immediate needle visualization and as consequence needle guidance during the block. In contrast to patient controlled analgesia using opioids, patients with a regional anesthetic technique suffer from fewer adverse events and show higher patient satisfaction; this is important as hospital rankings and advertisement have become more common worldwide and many patients use these factors in order to choose a certain institution for a specific procedure. This review provides a short overview of currently used regional anesthetic and analgesic techniques focusing on related implications, considerations and outcomes.

Effects of age on minimum effective volume of local anesthetic for ultrasound-guided supraclavicular brachial plexus block

BACKGROUND

Involutional changes of peripheral nervous system occur with aging. The aim of the study was to determine the minimum effective volume of local anesthetic required to offer an effective ultrasound-guided supraclavicular brachial plexus block in 50% of middle-aged (< 50 years) and elderly (> 65 years) patients. We hypothesized reduced minimum effective volume of local anesthetic in elderly patients.

METHODS

Middle-aged (n = 22) and elderly (n = 22) patients undergoing upper limb surgery received an ultrasound-guided supraclavicular brachial plexus block. Structural analysis of the brachial plexus in supraclavicular region was obtained by measuring the cross-sectional area. The prospective, observer-blinded study method is a previously validated step-up/step-down sequence model where the local anesthetic volume for the next patient is determined by the outcome of the previous block. The starting volume was 30 ml (50 : 50 mixture, 0.5%wt/vol levobupivacaine, 2%wt/vol lidocaine). The minimum effective volume of local anesthetic was determined using Dixon and Masey method.

RESULTS

The minimum effective local anesthetic volume significantly differed between middle-aged and elderly [23.0 ml, 95% confidence interval (CI) 13.7-32.3 vs. 11.9 ml, 95% CI 9.3-14.6; 95% CI of the difference 1.6-20.6, P = 0.027]. The cross-sectional area of brachial plexus was 0.95 ± 0.15 in middle-aged and 0.51 ± 0.06 cm(2) in elderly patients (P < 0.001).

CONCLUSIONS

Within the present study, we report a reduced minimum effective anesthetic volume for ultrasound-guided supraclavicular block in elderly patients. Additionally, smaller cross-sectional surface area of brachial plexus in the supraclavicular region was observed.

Anatomical investigations for appropriate needle positioning for thoracic paravertebral blockade in children

OBJECTIVE

Clinicians hesitate to perform thoracic paravertebral blockade (TPVB) in children due to the potential high risk of adverse effects. No paediatric anatomical guidelines for TPVB exist. This study aimed to estimate the appropriate depth and distance for safe needle positioning in children.

METHODS

The depth (D) from the skin to the paravertebral space and the distance (A) from the spinous process to the needle entry point on the skin were measured using chest computed tomography (CT) in children aged between 1 and 9 years. Correlations between age, gender, weight, height, body mass index (BMI) and each of the anatomical measurements were analysed.

RESULTS

Each measurement correlated significantly with age, weight and height, but not with BMI (n = 373 children). Measurements A and D could be calculated by: A = 13.56 + (0.33 × age [years]) + (0.06 × weight [kg]) + 0.47 × (gender [female = 0, male = 1]); and D = 17.49 - (0.35 × age [years]) + (0.55 × weight [kg]).

CONCLUSION

These anatomical guidelines for TPVB are recommended to help prevent anaesthetic complications such as pneumothorax, when ultrasonography and CT are unavailable.