Thoracic epidural catheters via the caudal and lumbar approaches using styletted multiple port catheters in pediatric patients: a report of three cases

Visceral versus somatic pain: an educational review of anatomy and clinical implications

Somatic and visceral nociceptive signals travel via different pathways to reach the spinal cord. Additionally, signals regulating visceral blood flow and gastrointestinal tract (GIT) motility travel via efferent sympathetic nerves. To offer optimal pain relief and increase GIT motility and blood flow, we should interfere with all these pathways. These include the afferent nerves that travel with the sympathetic trunks, the somatic fibers that innervate the abdominal wall and part of the parietal peritoneum, and the sympathetic efferent fibers. All somatic and visceral afferent neural and sympathetic efferent pathways are effectively blocked by appropriately placed segmental thoracic epidural blocks (TEBs), whereas well-placed truncal fascial plane blocks evidently do not consistently block the afferent visceral neural pathways nor the sympathetic efferent nerves. It is generally accepted that it would be beneficial to counter the effects of the stress response on the GIT, therefore most enhanced recovery after surgery protocols involve TEB. The TEB failure rate, however, can be high, enticing practitioners to resort to truncal fascial plane blocks. In this educational article, we discuss the differences between visceral and somatic pain, their management and the clinical implications of these differences.

Low-dose intrathecal local anesthetic does not increase the threshold current for the epidural stimulation test: a prospective observational trial of neuraxial analgesia in labouring women

PURPOSE

The purpose of this study was to investigate the ability of the electrical epidural stimulation test (EST) to determine the position of the epidural catheter during combined spinal-epidural (CSE) anesthesia for labour analgesia.

METHODS

This was a prospective observational trial of attempted EST during neuraxial analgesia in labouring women. Ten women received a double-segment CSE technique and one woman underwent continuous spinal analgesia following inadvertent dural puncture and deliberate placement of the catheter tip in the intrathecal space. In all CSE cases, the spinal injection was performed below the level of the epidural insertion. The motor threshold current (MTC) was determined by EST through the existing epidural/intrathecal catheter immediately following and at five, ten, and 15 mins after intrathecal injection of bupivacaine 1.75 mg and fentanyl 15 μg. Changes in the MTC were expressed as a percent change compared with baseline.

RESULTS

The MTC required to elicit muscle contractions in women with epidurally placed catheters was unaffected by the intrathecal injection of the analgesic mixture (P = 0.731). The MTC increased following an intrathecal injection of the same mixture in a woman who had the catheter placed intrathecally.

CONCLUSIONS

The intrathecal injection of a low dose of bupivacaine-fentanyl does not affect the MTC if the catheter is placed in the epidural space; however, it does affect the threshold if the catheter is placed intrathecally. We also confirm that the EST can help to determine the position of the epidural catheter prior to injection of the test dose. This trial was registered at ClinicalTrials.gov (NCT00464841).

Perioperative epidural analgesia in children undergoing major abdominal tumor surgery--a single center experience

PURPOSE

The purpose of this study was to assess the use of continuous epidural analgesia in pediatric patients undergoing major abdominal tumor surgery.

METHODS

Children undergoing major abdominal tumor surgery at our institution between 2008 and 2012 (n=40) received continuous epidural analgesia via an epidural catheter. Surgical trauma scores, pain scores, and clinical data of the children were compared to a pair-matched historical control group operated on between 2002 and 2007 without epidural analgesia.

RESULTS

Pain levels in the study group on day 1 and 3 after surgery were lower compared to the control group. The differences did, however, not reach statistical significance (p=0.15 and 0.09). Children in the study group received significantly fewer additional doses of piritramide or morphine (45% versus 82%, p<0.001). Despite significantly higher surgical trauma scores in the study group (p=0.018), there were no statistical differences regarding clinical parameters, such as mechanical ventilation time, time on intensive care unit, and total hospital stay. There were no catheter-related complications.

CONCLUSIONS

Continuous epidural analgesia is beneficial for children undergoing complex abdominal tumor surgery with regard to pain levels, postoperative recovery, and general clinical course. Expertise of the managing team, a careful patient selection, and a continuous quality assessment are essential for success.

Major complications related to epidural analgesia in children: a 15-year audit of 3,152 epidurals

BACKGROUND

Complications associated with epidural analgesia in children have a reported incidence of 40-90 in 10,000 epidurals. We sought to determine the incidence of major complications with the use of continuous epidural analgesia that occurred in our centre over the past 15 years and to describe the nature of these complications.

METHODS

The Acute Pain Service database at a tertiary care academic pediatric hospital was reviewed retrospectively over a 15-year period. Data were categorized according to patient age (neonate, infant, child one through eight years, and child > eight years), mode of insertion of the epidural (caudal, transsacral, lumbar, thoracic), complication type, and complication severity.

RESULTS

Over the 15-year period, 3,152 epidurals were performed. The use of caudal-thoracic epidurals in neonates and infants has increased since 2007. Twenty-four major complications were identified (incidence, 7.6 in 1,000 epidurals). The rate of complications in neonates was 4.2% compared with 1.4% in infants, 0.5% in children aged one through eight years, and 0.8% in children over eight years of age. The two most common complications were local skin infection and drug error.

CONCLUSIONS

Our incidence of major complications and our finding that complications were more common in neonates and infants are both consistent with previously published data. The two most common types of complications are potentially preventable.

Segmental dorsolumbar epidural analgesia via the caudal approach using multiple port catheters with ketamine or lidocaine or in combination in cattle

OBJECTIVE

To determine the analgesic and systemic effects of epidural administration of ketamine, lidocaine or a combination of ketamine/lidocaine in standing cattle.

STUDY DESIGN

Prospective, randomized, experimental trial.

ANIMALS

Six healthy male cattle weighing between 335 and 373 kg.

METHODS

The animals received 0.5 mg kg(-1) of ketamine (K), 0.2 mg kg(-1) of 2% lidocaine (L) or 0.25 mg kg(-1) ketamine plus 0.1 mg kg(-1) lidocaine (KL). All the drugs were injected into the dorsolumbar epidural space via a caudal approach through a non-styletted multiple-port catheter. Each animal received each treatment at random. Evaluations of analgesia, sedation, ataxia, heart rate, arterial pressure, respiratory rate, skin temperature and rectal temperature were obtained at 0 (basal), 5, 10, 15, 30, 45, 60, 75, 90 minutes after epidural injection, and then at 30-minute intervals until loss of analgesia occurred. Skin temperature was taken at these intervals up to 60 minutes. All the animals received a standard noxious stimulus; a 4-point scale was used to score the response. A second scale was used to score ataxia and a third for sedation.

RESULTS

The duration of analgesia in the upper and lower flanks in cattle was 140 +/- 15, 50 +/- 14 and 80 +/- 22 minutes (mean +/- SD) after dorsolumbar epidural KL, K or L, respectively. The cardiovascular changes were within acceptable limits in these clinically healthy cattle.

CONCLUSIONS

Dorsolumbar epidural administration of KL to cattle resulted in longer duration of analgesia of the upper and lower flanks in standing conscious cattle, than the administration of K or L alone.

CLINICAL RELEVANCE

Further research is necessary to determine whether this combination using this technique provides sufficient analgesia for flank surgery in standing cattle.

Evaluation of segmental dorsolumbar epidural analgesia with ketamine hydrochloride administered by use of nonstyletted multiple-port catheters via the caudal approach in cattle

OBJECTIVE

To evaluate use of nonstyletted multiple-port catheters for epidural administration of ketamine hydrochloride via the caudal approach to induce analgesia of the paralumbar fossa (flank) in cattle.

ANIMALS

6 healthy bulls.

PROCEDURES

1 week before experiments began, a multiple-port catheter was inserted by use of a Tuohy needle in all cattle via the caudal approach (between the first and second coccygeal vertebrae); the tip was threaded approximately 48 cm cranial into the dorsolumbar region. Each bull was administered ketamine (0.3, 0.5, or 0.7 mg/kg) at time 0. Heart rate, blood pressures, respiratory rate, rectal temperature, analgesia, sedation, and ataxia were determined before treatment (baseline [time 0]); at 5, 10, 15, 30, 45, 60, 75, and 90 minutes; and every 30 minutes thereafter until end of analgesia.

RESULTS

All multiple-port catheters were threaded with negligible resistance into the dorsolumbar region in all bulls. All doses of ketamine were effective for inducing analgesia of the flank region of bulls in a standing position. Total analgesia time was dose dependent (35, 50, and 80 minutes for 0.3, 0.5, and 0.7 mg/kg, respectively). All doses of ketamine induced mild or moderate ataxia. Heart rate changes were within acceptable limits.

CONCLUSIONS AND CLINICAL RELEVANCE

Segmental dorsolumbar epidural analgesia with ketamine administered via multiple-port catheters by use of the caudal approach in cattle was feasible, and the cattle remained standing with minimal adverse effects. Further studies are necessary to determine whether this technique provides optimal conditions to allow surgery in standing cattle.

An evaluation of the epidural catheter position by epidural nerve stimulation in conjunction with continuous epidural analgesia in adult surgical patients

BACKGROUND

The epidural stimulation test to confirm epidural catheter position has been described as being simple, fast, and reliable. We evaluated the feasibility of the epidural stimulation test and its potential in contributing to effective postoperative continuous epidural analgesia.

METHODS

Thirty adult patients (ASA I-III) undergoing major abdominal surgery or thoracotomy were to receive continuous epidural analgesia at a thoracic level postoperatively. The epidural stimulation test was performed after catheter placement, after local anesthetic boluses, and during epidural analgesia, up to six times in each patient. Catheter positions were verified by epidurography (before start of epidural analgesia and again on the second postoperative day).

RESULTS

Several technical issues (e.g., need to flush catheter with saline in order to maintain adequate stimulation during >25% of all measurements) and interpretation problems (e.g., interference of respiratory activity [n = 6]) made the implementation of the epidural stimulation test rather time consuming, both at the time of catheter placement and during epidural analgesia. Immediately after catheter placement (before test dose) the epidural stimulation test did not identify four of four catheters positioned outside the spinal canal. In addition, the initial epidural stimulation test indicated a possible intrathecal or paravertebral placement in 3 of 25 catheters correctly positioned in the epidural space. During 107 of 122 (88%) measurements with the catheter tip situated epidurally and with preceding or simultaneous administration of epidural local anesthetic, the epidural stimulation test elicited a motor response. Continuous epidural analgesia provided adequate pain relief in all 25 patients having positive epidurography.

CONCLUSIONS

The epidural stimulation test was often associated with technical difficulties and interpretation problems. The role of the repeated use of the epidural stimulation test for quality assurance in patients undergoing postoperative continuous epidural analgesia remains undetermined.

Cervical epidural analgesia via a thoracic approach using nerve-stimulation guidance in adult patients undergoing total shoulder replacement surgery

BACKGROUND

Continuous cervical epidural anesthesia can provide excellent peri- and post-operative analgesia, although several factors prevent its widespread use. Advancing catheters from thoracic levels to the cervical region may circumvent these barriers, provided they are accurately positioned. We hypothesize that guiding catheters from thoracic to cervical regions using low-current epidural stimulation will have a high success rate and enable excellent analgesia in adults undergoing total shoulder arthroplasty.

METHODS

After Institutional Review Board approval, adult patients were studied consecutively. A 17-G Tuohy needle was inserted into the thoracic epidural space using a right paramedian approach with loss of resistance. A 20-G styletted epidural catheter, with an attached nerve stimulator, was primed with saline and a 1-10 mA current was applied as it advanced in a cephalad direction towards the cervical spine. Muscle twitch responses were observed and post-operative X-ray confirmed final placement. After a test dose, an infusion (2-8 ml/h) of ropivacaine 2 mg/ml and morphine 0.05 mg/ml (or equivalent) was initiated. Verbal analog pain scale scores were collected over 72 h.

RESULTS

Cervical epidural anesthesia was performed on 10 patients. Average current required to elicit a motor response was 4.8 +/- 2.0mA. Post-operative X-ray of catheter positions confirmed all catheter tips reached the desired region (C4-7). The technical success rate for catheter placement was 100% and excellent pain control was achieved. Catheters were positioned two to the left, four to the right and four to the midline.

CONCLUSION

This epidural technique provided highly effective post-operative analgesia in a patient group that traditionally experiences severe post-operative pain and can benefit from early mobilization.

Innovative approaches to neuraxial blockade in children: the introduction of epidural nerve root stimulation and ultrasound guidance for epidural catheter placement

Continuous epidural blockade remains the cornerstone of pediatric regional anesthesia. However, the risk of catastrophic trauma to the spinal cord when inserting direct thoracic and high lumbar epidural needles in anesthetized or heavily sedated pediatric patients is a concern. To reduce this risk, research has focused on low lumbar or caudal blocks (ie, avoiding the spinal cord) and threading catheters from distal puncture sites in a cephalad direction. However, with conventional epidural techniques, including loss-of-resistance for localization of the needle, optimal catheter tip placement is difficult to assess because considerable distances are required during threading. Novel approaches include electrical epidural stimulation for physiological confirmation and segmental localization of epidural catheters, and ultrasound guidance for assessing related neuroanatomy and real-time observation of the needle puncture and, potentially, catheter advancement. The present article provides a brief and focused review of these two advances, and outlines recent clinical experiences relevant to pediatric epidural anesthesia.