Erector spinae plane blocks: A narrative update

The erector spinae plane block (ESPB) is perhaps one of the most interesting of the tissue plane blocks described recently. There has been an exponential increase in the number of publications for both adults and children over the past 5 years. Single-shot, intermittent bolus, and continuous infusion techniques have been used effectively. Both the efficacy and safety of the procedure are widely accepted, but the exact mechanism by which the local anesthetic spreads from the tip of the transverse process to block the dorsal and ventral rami of the spinal nerves is controversial and needs clarification. Anatomical differences in children, particularly in neonates and infants, may explain the spread in this age group. In most pediatric studies, erector spinae plane block was opioid sparing, and noninferiority was observed when compared with other regional techniques.

Airway management in the paediatric difficult intubation registry: a propensity score matched analysis of outcomes over time

Background

The Paediatric Difficult Intubation Collaborative identified multiple attempts and persistence with direct laryngoscopy as risk factors for complications in children with difficult tracheal intubations and subsequently engaged in initiatives to reduce repeated attempts and persistence with direct laryngoscopy in children. We hypothesised these efforts would lead to fewer attempts, fewer direct laryngoscopy attempts and decrease complications.

Methods

Paediatric patients less than 18 years of age with difficult direct laryngoscopy were enrolled in the Paediatric Difficult Intubation Registry. We define patients with difficult direct laryngoscopy as those in whom (1) an attending or consultant obtained a Cormack Lehane Grade 3 or 4 view on direct laryngoscopy, (2) limited mouth opening makes direct laryngoscopy impossible, (3) direct laryngoscopy failed in the preceding 6 months, and (4) direct laryngoscopy was deferred due to perceived risk of harm or poor chance of success. We used a 5:1 propensity score match to compare an early cohort from the initial Paediatric Difficult Intubation Registry analysis (August 6, 2012-January 31, 2015, 785 patients, 13 centres) and a current cohort from the Registry (March 4, 2017-March 31, 2023, 3925 patients, 43 centres). The primary outcome was first attempt success rate between cohorts. Success was defined as confirmed endotracheal intubation and assessed by the treating clinician. Secondary outcomes were eventual success rate, number of attempts at intubation, number of attempts with direct laryngoscopy, the incidence of persistence with direct laryngoscopy, use of supplemental oxygen, all complications, and severe complications.

Findings

First-attempt success rate was higher in the current cohort (42% vs 32%, OR 1.5 95% CI 1.3-1.8, p < 0.001). In the current cohort, there were fewer attempts (2.2 current vs 2.7 early, regression coefficient -0.5 95% CI -0.6 to -0.4, p < 0.001), fewer attempts with direct laryngoscopy (0.6 current vs 1.0 early, regression coefficient -0.4 95% CI -0.4 to 0.3, p < 0.001), and reduced persistence with direct laryngoscopy beyond two attempts (7.3% current vs 14.1% early, OR 0.5 95% CI 0.4-0.6, p < 0.001). Overall complication rates were similar between cohorts (19% current vs 20% early). Severe complications decreased to 1.8% in the current cohort from 3.2% in the early cohort (OR 0.55 95% CI 0.35-0.87, p = 0.011). Cardiac arrests decreased to 0.8% in the current cohort from 1.8% in the early cohort. We identified persistence with direct laryngoscopy as a potentially modifiable factor associated with severe complications.

Interpretation

In the current cohort, children with difficult tracheal intubations underwent fewer intubation attempts, fewer attempts with direct laryngoscopy, and had a nearly 50% reduction in severe complications. As persistence with direct laryngoscopy continues to be associated with severe complications, efforts to limit direct laryngoscopy and promote rapid transition to advanced techniques may enhance patient safety.

Funding

None.

Thoracic regional anesthesia and the impact on ventilation

Thoracic surgical incisions can be associated with intense pain or discomfort. Postoperative thoracic pain may be multifactorial in origin. Inadequate analgesia causes respiratory dysfunction. Adequate analgesia preserves pulmonary function and may hasten recovery. Intravenous opioids are widely used but sufficient analgesia is seldom achieved in doses that permit safe spontaneous ventilation. Thoracic regional anesthesia provides profound analgesia, is opiate sparing and has minimal depressant effects on ventilation. Thoracic regional anesthesia is both an effective alternative to systemic analgesics or can be used as part of a multimodal analgesic technique.

The utility of ultrasonography in anesthesia management in 3 cases of caudal regression syndrome

Caudal regression syndrome is an extremely rare clinical entity. It is a challenge to anesthesiologist due to its multisystem involvement. Regional anesthesia literature on caudal regression syndrome is scarce. We report three cases where optimal use of ultrasonography aided in providing satisfactory peri-operative pain relief. Furthermore, a cogent and a logical review of the decision-making processes for the regional blockade in children with caudal regression syndrome are presented.

The anatomical features of an ultrasound-guided erector spinae fascial plane block in a cadaveric neonatal sample

BACKGROUND

Since its inception, the erector spinae plane block has been used for a variety of truncal surgeries with success in both adults and children. However, the anatomical features, route of spread, and dermatomal coverage are still not fully understood in a pediatric population.

OBJECTIVES

To identify the anatomical features of the erector spinae fascial plane space by replicating an erector spinae plane block in a fresh neonatal cadaveric sample. The primary aim was to determine the spread of the dye within the fascial plane, while the secondary aims were to determine whether the needle direction or entry site affected the spread.

METHODS

The block was replicated bilaterally using 0.1 mL/kg of iodinated contrast dye in nine fresh unembalmed preterm neonatal cadavers. The dye was introduced under ultrasound guidance at vertebral level T5 and T8. Additionally, the needle was oriented cranial-caudal vs caudal-cranial to determine if the needle orientation influenced the spread of dye. The block was also replicated midway between the adjacent transverse processes as opposed to the lateral tip of the transverse process to determine the spread.

RESULTS

From the total sample size, 14 "blocks" were successfully replicated, while 4 "blocks" were either incomplete or failed blocks. Contrast dye was found in the paravertebral, intercostal, and epidural spaces, including posteriorly over the neural foramina. Results revealed that the needle direction or entry site did not influence the spread within the fascial plane.

CONCLUSION

Contrast material was found in the paravertebral, epidural, and intercostal spaces over an average of 5 vertebral levels when using 0.1 mL/kg.

Clonidine as an Adjuvant to Bupivacaine for Suprazygomatic Maxillary Nerve Blocks in Cleft lip and Palate Repair: A Randomized, Prospective, Double-Blind Study

OBJECTIVES

Does clonidine, as adjuvant to bupivacaine for suprazygomatic maxillary nerve blocks, reduce emergence agitation in patients undergoing cleft lip and cleft palate surgery?

DESIGN

Randomized, controlled, and double-blind study.

SETTING

Guwahati Comprehensive Cleft Care Center, Guwahati (Assam, India).

PARTICIPANTS

A total of 124 patients; with a median age of 5 years in the clonidine group (CLG) and 7 years in the control group (CG), who underwent cleft lip or cleft palate surgery were included. Exclusion criteria included lack of consent from patients or their guardians, allergy to local anesthetics, coagulation disorders, local infection at the puncture site before performing the block, and language difficulties or cognitive disorders.

INTERVENTIONS

Patients were randomized into 2 groups to receive bilateral suprazygomatic maxillary nerve blocks with either a bupivacaine/clonidine mixture for the CLG or bupivacaine alone in the CG.

MAIN OUTCOME MEASURE

The primary end point was the incidence of emergence agitation.

RESULTS

There was a statistically significant difference in the incidence of emergence agitation (30.2% in the CG compared to 15.2% in the CLG; difference of incidences: 15%, 95% CI: 0.1-30.1). The percentage of patients requiring intraoperative Fentanyl was lower in the CLG (10.6% compared to 26.4%; difference of incidences: 15.8%, 95% CI: 1.8-29). No other differences were observed. Further research in a more typically aged children population undergoing cleft surgery is needed.

CONCLUSIONS

The use of clonidine as an adjuvant to bupivacaine in maxillary nerve block reduces the incidence of emergence agitation and intraoperative opioid consumption without hemodynamic or sedative side effects in patients undergoing cleft lip and palate surgery.

Variation in pediatric local anesthetic dosing for peripheral nerve blocks: an analysis from the Pediatric Regional Anesthesia Network (PRAN)

Background

Variation of local anesthetic dosing has been reported for adult peripheral nerve blocks (PNBs) and infant caudal blocks. As higher doses of local anesthetics (LA) are potentially associated with increased risk of complications (eg, local anesthetic systemic toxicity), it is important to understand the source of LA dose variation. Using the Pediatric Regional Anesthesia Network (PRAN) database, we aimed to determine if variation in dosing exists in pediatric single-injection PNBs, and what factors influence that variation.

The primary aim of this study was to determine the factors associated with dosing for the 10 most commonly performed PNBs, with the secondary aim of exploring possible factors for variation such as number of blocks performed versus geographic location.

Methods

The PRAN database was used to determine the 10 most common pediatric PNBs, excluding neuraxial regional anesthetics. The 10 most common pediatric PNBs in the PRAN database were analyzed for variation of LA dose and causes for variation.

Results

In a cohort of 34 514 children receiving PNBs, the mean age was 10.38 (+/-5.23) years, average weight was 44.88 (+/-26.66) kg and 61.8% were men. The mean bupivacaine equivalent (BE) dose was 0.86 (+/-0.5) mg kg−1 and ropivacaine was used in 65.4% of blocks. Dose decreases with age (estimate −0.016 (−0.017, –0.015; p<0.001)). In all blocks for all age groups, the range of doses that make up the central 80% of all doses exceeds the mean BE dose for the block. Variation is not related to the number blocks performed at an institution (p=0.33 (CI −0.42 to 0.15)). The dose administered for a PNB is driven in order of impact by the institution where the block was performed (Cohen’s ƒ=0.45), then by weight (0.31), type of block (0.27), LA used (0.15) and age (0.03).

Conclusions

Considerable variation in dosing exists in all age groups and in all block types. The most impactful driver of local anesthetic dose is the institution where the block was performed, indicating the dosing of a potentially lethal drug is more based on local culture than on evidence.

The extent of cranio-caudal spread within the erector spinae fascial plane space using computed tomography scanning in a neonatal cadaver

BACKGROUND

The erector spinae plane block (ESP) is a novel approach for blockade of the spinal nerves in infants, children, and adults. Until recently, the gold standard for truncal procedures includes the paravertebral and epidural blocks. However, the exact mechanism by which this blockade is achieved is subject to debate.

METHODS

2.3 mL (1 mL/kg) of iodinated contrast dye was injected bilaterally into the erector spinae fascial plane of a fresh unembalmed preterm neonatal cadaver (weighing 2.3 kg), to replicate the erector spinae plane block and to track the cranio-caudal spread of the contrast dye using computed tomography. The "block" was performed at vertebral level T8 on the right-hand side and at vertebral level T10 on the left-hand side.

RESULTS

Contrast dye was spread over three dermatomal levels from T6 to T9 on the right-hand side, while on the left-hand side, the spread was seen over four dermatomal levels from T9 to T11/12. Contrast dye also spread over the costotransverse ligament, into the paravertebral space and further lateral from the lateral border of the erector spinae muscle into the intercostal space. However, no spread was seen in the epidural space.

CONCLUSION

The erector spinae plane block is a versatile technique that can be part of the multimodal postoperative analgesic strategy for truncal surgery. In this study, contrast material dye was tracked over four vertebral levels in the paravertebral space (suggesting an approximate volume of 0.5-0.6 mL per dermatome).

A cadaveric study of the erector spinae plane block in a neonatal sample

Background

The aim of this article was to provide a detailed description of the neonatal anatomy related to the erector spinae plane block and to report the spread of the dye within the fascial planes and potential dermatomal coverage.

Methods

Using ultrasound guidance, the bony landmarks and anatomy of the erector spinae fascial plane space were identified. The erector spinae plane block was then replicated unilaterally in two fresh unembalmed neonatal cadavers. Using methylene blue dye, the block was performed at vertebral levels T5—using 0.5 mL in cadaver 1—and T8—using 0.2 mL in cadaver 2. The craniocaudal spread of dye was tracked within the space on the ultrasound screen and further confirmed on dissection.

Results

Craniocaudal spread was noted from vertebral levels T3 to T6 when the dye was introduced at vertebral level T5 and from vertebral levels T7 to T11 when the dye was introduced at vertebral level T8. Furthermore, the methylene blue spread was found anteriorly in the paravertebral and epidural spaces, staining both the dorsal and ventral rami of the spinal nerves T2 to T12. Small amounts of dye were also found in the intercostal spaces.

Conclusion

In two neonatal fresh cadavers, the dye was found to spread to multiple levels and key anatomic locations.

Comparison between epidural and opioid analgesia for infants undergoing major abdominal surgery

BACKGROUND

Epidural analgesia is considered optimal for postoperative pain management after major abdominal surgery. The potential to decrease anesthetic and opioid exposure is particularly desirable for infants, given their vulnerability to respiratory depression and concern for anesthetic neurotoxicity. We reviewed our experience with infants undergoing major abdominal surgery to determine if epidural catheter use decreased anesthetic and opioid exposure and improved postoperative analgesia.

METHODS

This retrospective cohort study included infants (<12 months) who underwent exploratory laparotomy, ureteral reimplantation, or bladder exstrophy repair between November 2011 and November 2014. Primary outcomes of anesthetic exposure (mean endtidal sevoflurane) and intraoperative opioid administration were compared between infants who received epidural catheters and those who did not. Secondary outcomes included postoperative pain and sedation scores and morphine equivalents administered 0-24 and 24-48 hours after surgery.

RESULTS

Of 158 eligible infants, 82 were included and 47 received epidurals. Patients with epidurals underwent bladder exstrophy repair (N = 9), ureteral reimplantation (N = 8), and exploratory laparotomy (N = 30). Infants with epidurals received less intraoperative fentanyl (2.6 mcg/kg (0,4.5) vs 3.3 mcg/kg (2.4,5.8), P = 0.019) and morphine (6% (3/47) vs 26% (9/35), P = 0.014) in univariate analysis. After controlling for age and emergency surgery, differences in long-acting opioid administration persisted, with significantly less morphine given in the epidural group (OR 0.181; 95% CI 0.035-0.925; P = 0.040). Mean endtidal sevoflurane concentrations were similar between groups. There was no significant difference in postoperative median morphine equivalents.

CONCLUSION

Placement of epidural catheters in infants undergoing major abdominal surgery is associated with decreased long-acting opioid requirements intraoperatively. Epidural placement does not preclude opioid exposure however, as opioids may be administered for indications other than nociceptive pain in the difficult-to-assess postoperative infant. Further prospective studies are warranted to better quantify the effect of epidural analgesia on intraoperative anesthetic exposure in infants.

Endoscopic Versus Open Repair for Craniosynostosis in Infants Using Propensity Score Matching to Compare Outcomes: A Multicenter Study from the Pediatric Craniofacial Collaborative Group

BACKGROUND

The North American Pediatric Craniofacial Collaborative Group (PCCG) established the Pediatric Craniofacial Surgery Perioperative Registry to evaluate outcomes in infants and children undergoing craniosynostosis repair. The goal of this multicenter study was to utilize this registry to assess differences in blood utilization, intensive care unit (ICU) utilization, duration of hospitalization, and perioperative complications between endoscopic-assisted (ESC) and open repair in infants with craniosynostosis. We hypothesized that advantages of ESC from single-center studies would be validated based on combined data from a large multicenter registry.

METHODS

Thirty-one institutions contributed data from June 2012 to September 2015. We analyzed 1382 infants younger than 12 months undergoing open (anterior and/or posterior cranial vault reconstruction, modified-Pi procedure, or strip craniectomy) or endoscopic craniectomy. The primary outcomes included transfusion data, ICU utilization, hospital length of stay, and perioperative complications; secondary outcomes included anesthesia and surgical duration. Comparison of unmatched groups (ESC: N = 311, open repair: N = 1071) and propensity score 2:1 matched groups (ESC: N = 311, open repair: N = 622) were performed by conditional logistic regression analysis.

RESULTS

Imbalances in baseline age and weight are inherent due to surgical selection criteria for ESC. Quality of propensity score matching in balancing age and weight between ESC and open groups was assessed by quintiles of the propensity scores. Analysis of matched groups confirmed significantly reduced utilization of blood (26% vs 81%, P < .001) and coagulation (3% vs 16%, P < .001) products in the ESC group compared to the open group. Median blood donor exposure (0 vs 1), anesthesia (168 vs 248 minutes) and surgical duration (70 vs 130 minutes), days in ICU (0 vs 2), and hospital length of stay (2 vs 4) were all significantly lower in the ESC group (all P < .001). Median volume of red blood cell administered was significantly lower in ESC (19.6 vs 26.9 mL/kg, P = .035), with a difference of approximately 7 mL/kg less for the ESC (95% confidence interval for the difference, 3-12 mL/kg), whereas the median volume of coagulation products was not significantly different between the 2 groups (21.2 vs 24.6 mL/kg, P = .73). Incidence of complications including hypotension requiring treatment with vasoactive agents (3% vs 4%), venous air embolism (1%), and hypothermia, defined as <35°C (22% vs 26%), was similar between the 2 groups, whereas postoperative intubation was significantly higher in the open group (2% vs 10%, P < .001).

CONCLUSIONS

This multicenter study of ESC versus open craniosynostosis repair represents the largest comparison to date. It demonstrates striking advantages of ESC for young infants that may result in improved clinical outcomes, as well as increased safety.

Safety of antifibrinolytics in cranial vault reconstructive surgery: a report from the pediatric craniofacial collaborative group

BACKGROUND

Antifibrinolytic therapy significantly decreases blood loss and transfusion in pediatric cranial vault reconstructive surgery; however, concern regarding the side effects profile limits clinical use.

AIMS

The aim was to utilize the Pediatric Craniofacial Surgery Perioperative Registry database to identify the safety profile of antifibrinolytic therapy for cranial vault reconstructive surgery by reporting the incidence of adverse events as they relate to exposure to tranexamic acid and aminocaproic acid compared to no exposure to antifibrinolytics.

METHODS

The database was queried for cases of open cranial vault reconstructive surgery. Less invasive procedures such as neuro-endoscopic and spring-mediated cranioplasties were excluded. The outcomes evaluated included any perioperative neurological adverse event including seizures or seizure-like movements and thromboembolic events.

RESULTS

Thirty-one institutions reported a total of 1638 cases from 2010 to 2015. Total antifibrinolytic administration accounted for 59.5% (tranexamic acid, 36.1% and aminocaproic acid, 23.4%), with 40.5% not receiving any antifibrinolytic. The overall incidence of postoperative seizures or seizure-like movements was 0.6%. No significant difference was detected in the incidence of postoperative seizures between patients receiving tranexamic acid and those receiving aminocaproic acid [the odds ratio for seizures being 0.34 (95% confidence interval: 0.07-1.85) controlling for American Society of Anesthesia (ASA) physical class] nor in patients receiving antifibrinolytics compared to those not administered antifibrinolytics (the odds ratio for seizures being 1.02 (confidence interval 0.29-3.63) controlling for ASA physical class). One complicated patient in the antifibrinolytic group with a femoral venous catheter had a postoperative deep venous thrombosis.

CONCLUSIONS

This is the first report of an incidence of postoperative seizures of 0.6% in pediatric cranial vault reconstructive surgery. There was no significant difference in postoperative seizures or seizure-like events in those patients who received the tranexamic acid or aminocaproic acid vs those that did not. This report provides evidence of the safety profile of antifibrinolytic in children having noncardiac major surgery. Caution should prevail however in using antifibrinolytic in high-risk patients. Antifibrinolytic dosage regimes should be based on pharmacokinetic data avoiding high doses.

Adjuvants in pediatric regional anesthesia

SUMMARY Local anesthetics have a limited duration of action. Adjuvants are used to prolong the duration of action and to augment analgesia allowing lower concentrations of local anesthetic to be used. Adjuvants have been used more extensively with neuraxial blocks, particularly caudal epidural blocks, but more recently to supplement peripheral nerve blocks. Intrathecal adjuvants are not covered in this review since spinal anesthesia is not widely used in children except in ex-premature infants. Morphine is the historical gold-standard with which other adjuvants are compared. Clonidine is most useful and is becoming increasingly popular, while the side-effect profile of other agents reduces their utility. Concerns with regard to the neurotoxicity of ketamine in animal models has led to its withdrawal in some countries.

Regional anesthesia in neonates and infants

Optimal pain management can significantly impact the surgical outcome and length of stay in the neonatal intensive care unit (NICU). Regional anesthesia is an effective alternative that can be used in both term and preterm neonates. A variety of neuraxial and peripheral nerve blocks have been used for specific surgical and NICU procedures. Ultrasound guidance has increased the feasibility of using these techniques in neonates. Education and training staff in the use of continuous epidural infusions are important prerequisites for successful implementation of regional anesthesia in NICU management protocols.

Everyday regional anesthesia in children

Regional anesthesia in children is an evolving technique with many advantages in perioperative management. Although most regional anesthesia techniques are sufficiently described in the literature, the implementation of these techniques into daily clinical practice is still lacking. The main problems associated with pediatric regional anesthesia (PRA) include the appropriate selection of blockade, the management around the block, and how to teach these techniques in an optimal manner. This review article provides an overview of these 'hot' topics in PRA.

Regional anesthesia in children: the future

Pediatric regional anesthesia continues to evolve. Education and attention to anatomical detail remain key elements to successful outcomes. New techniques, some adapted from adult practice, provide analgesia for pediatric surgical procedures such cleft palate or congenital hip dysplasia. Despite technological advances a number of controversial issues remain unresolved.

Epidural catheter placement in neonates: sonoanatomy and feasibility of ultrasonographic guidance in term and preterm neonates

BACKGROUND

We report the first prospective sonoanatomic study in neonates with the aim to perform ultrasonographic-guided epidural catheter placement in this age group.

METHOD

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.

RESULTS

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.

CONCLUSION

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.

Validation of a six-graded faces scale for evaluation of postoperative pain in children

BACKGROUND

The faces pain scales are often used for self-report assessment of paediatric pain. The aim of this study was to evaluate the validity of a six-graded faces pain scale after surgery by comparing the level of agreement between the children's report of faces pain scores and experienced nurses' assessment of pain by observation of behaviour. The faces pain scores before, at and after administration of analgesics were analysed. The study was performed in two South African hospitals, one with a mainly rural population and the other with an urban population.

METHODS

A total of 110 children aged 4-12 years, scheduled for inguinal surgery in the two South African hospitals, were included in the study. The anaesthetic technique was standardized. All patients received a caudal block preoperatively. Postoperative pain assessments were made every hour for 8 h after the caudal block was performed. A designated nurse assessed pain by using a four-graded descriptive scale (no, mild, moderate or severe pain) and thereafter the child reported pain by using the six-graded faces pain scale.

RESULTS

A high correlation was found between the two methods of assessment (tau = 0.76, P < 0.0001). The correlation between methods was high in both hospital populations and in all age groups. The weakest correlation was found in children aged 8-12 years (tau = 0.56, P < 0.01). Significantly lower faces pain scores were found after administration of analgesics compared with pain rating before analgesics (P < 0.0001). The proportion of patients with pain scores above 2 decreased from 86% to 31% (P < 0.001).

CONCLUSIONS

The findings support this six-graded faces pain scale as a useful and valid instrument for measuring pain in the postoperative period in children aged 4-12 years.

The efficacy of caudal ropivacaine 1, 2 and 3 mg x l(-1) for postoperative analgesia in children

BACKGROUND

The aim of this double blind, randomized, comparative study was to assess the analgesic efficacy and incidence of motor block after caudal block using three different concentrations of ropivacaine, 1, 2 and 3 mg x l(-1), in children 4-12-year-old.

METHODS

One hundred and ten children ASA I-II, scheduled for inguinal surgery, were included in the study. After induction of a standardized general anaesthetic technique, all patients received 1 ml x kg(-1) of the ropivacaine solution for a caudal block and were assessed for 8 h after the injection.

RESULTS

The ropivacaine was well tolerated in all patients. Median time to treatment with analgesics was 3.3, 4.5 and 4.2 h in the 1, 2 and 3 mg x ml(-1) groups, respectively. During the first 4 h, the pain scores for both a 6-graded faces scale and a 4-graded observer scale were higher in the 1 mg x ml(-1) group than the 3 mg x ml(-1) group. The median sensory block reached T12 in all groups 1 h after the caudal block. Thereafter, the speed of regression was correlated with the ropivacaine concentration. In the patients with a sensory block from T12 and above, the median time to treatment with analgesics was longer than in the children with a sensory block below T12. The incidence of motor block was 28% in the 3 mg x ml(-1) group in comparison with 0 and 13% in the 1 and 2 mg x ml(-1) groups.

CONCLUSIONS

It was concluded that 1 ml x kg(-1) of ropivacaine 2 mg x ml(-1) for caudal block provided satisfactory postoperative pain relief after inguinal surgery in 4-12-year-old children. Ropivacaine 1 mg x ml(-1) showed less efficacy while the use of ropivacaine 3 mg x ml(-1) was associated with a higher incidence of motor block with minimal improvement in postoperative pain relief.

Pulse oximetry during cardiac catheterization in children with congenital heart disease

One hundred and five children with congenital heart disease were monitored by pulse oximetry during cardiac catheterization. Excellent correlation (r = 0.95) was found between oxygen saturation values obtained with pulse oximetry and those obtained from arterial blood in 133 data pairs. This correlation was described by the regression equation y = 0.91x + 8.1. The correlation was also excellent in 47 data pairs with saturation values of less than 90% (r = 0.94, y = 0.93x + 6.0) from 36 cyanotic children. The clinical usefulness of pulse oximetry in the early recognition of decreased pulmonary blood flow or partial airway obstruction was demonstrated. Early diagnosis of changes in oxygenation was especially helpful in children with cyanotic congenital heart disease, in whom small changes in arterial oxygen tension may cause large changes in oxygen saturation.