Incidents relating to paediatric regional anaesthesia in the first 8000 cases reported to webAIRS

Technical issues

Reported incidents ranged from minor to unexpected and unusual events. The first incident described the events following a combined single shot caudal plus spinal in a neonate for an awake general surgical procedure. The patient was a premature neonate with multiple comorbidities, including apnoea of prematurity and chronic lung disease requiring oxygen therapy. Anaesthesia was initially routine with 0.2 mL/kg of 0.5% bupivacaine injected intrathecally followed by 0.9 mL/kg of 0.2% ropivacaine plus 1 mL normal saline caudally (equating to a total of 2.7mg/kg local anaesthetic). Shortly after the caudal injection, the neonate displayed signs of respiratory distress leading to hypoxia, bradycardia and hypotension, requiring face-mask ventilation and subsequent intubation. The surgical procedure was then performed under general anaesthetic. The patient was extubated post-procedure to their preoperative oxygen supplementation, with no further sequelae. The reporter surmised that the combined regional technique contributed to this event. They hypothesised that injection of the caudal local anaesthetic caused extension of spinal anaesthesia through compression of the dura.

Combined caudal with spinal anaesthesia is a novel technique for awake neonatal anaesthesia. ^{9 , 10} More commonly described is the placement of a caudal catheter for additional local anaesthetic administration at the time when the spinal anaesthesia recedes, rather than a simultaneous single-shot injection. ¹⁰ A simultaneous single-shot caudal plus spinal technique may pose additional risk ¹¹ of adverse events, particularly related to dosing. The described incident may demonstrate ‘epidural volume extension’, a concept more commonly described with adult neuraxial anaesthesia. ¹¹ The compressive effects of a volume of injectate in the epidural space may cause cranial extension of spinal injectate. Although dosing recommendations to either space are contested, a dose reduction for spinal anaesthesia in the presence of epidural anaesthesia is suggested for adults. ¹¹ Extrapolating to infants and this incident, it is possible that the patient may have experienced ‘high spinal’ anaesthesia due to maximum spinal anaesthetic dosage and maximum caudal anaesthetic dosage. However, the differential diagnoses include the possibility of intrathecal spread of epidural drug, possible subdural injection or even LAST. Further research and experience are required to describe the safety of this technique and appropriate drug dosages.

There were four further incidents reported in which minor technical issues contributed: two involved attempted epidural catheter insertion with accidental dural puncture in pre-school aged children. Another patient with cerebral palsy and scoliosis had an epidural sited pre-surgically for a complex orthopaedic procedure. Intraoperatively the epidural was not providing the expected level of analgesia and was resited postoperatively with better results. The final case involved an ultrasound-guided paravertebral block in a pre-school aged patient. The surgeons noted a breach of the parietal pleura on thoracoscopy, with localised air leak. This resolved by the end of the case and the patient received a pleural drain.

The above incidents demonstrate recognised complications and highlight the potential challenge of regional anaesthesia in young paediatric patients, children with abnormal musculoskeletal anatomy, and less frequently utilised techniques in paediatric anaesthetic practice. It is reassuring that none of the patients were reported to suffer from severe sequelae, and adequate pain control was still achieved with a regional technique in all cases.

Equipment issues

A 20 gauge Abbocath intravenous catheter was sheared during single shot injection into the caudal space. The authors provided limited information about the specific cause of this incident and categorised this as a medical device malfunction. A 15 mm segment of the catheter remained lodged within the sacral hiatus. Guidance from the neurosurgery team was sought, and their advice was to leave the fragment in place. Limited information was reported for this incident and the overall outcome. Literature for the treatment of this complication is scarce and conflicting for both adults and children. Some case studies describe surgical removal of sequestered epidural catheters without complications. ¹² Other case reports have advised to leave the catheter in situ, provided it is not positioned intrathecally. ^{13 , 14} The consequences of an in situ catheter for a developing child are largely unknown, but are postulated to be infection, fibrosis, catheter migration and nerve injury. In all case reports urgent neurosurgical opinion and cross-sectional imaging (computed tomography) were obtained to locate the fragments and dictate the next course of action. Lenox et al. ¹² suggest as a general rule, that catheters retained within the skin but outside the epidural canal can be easily removed. For catheters within the spinal canal, a multidisciplinary discussion involving anaesthetists, neurosurgeons and the family should weigh the pros and cons of operative intervention versus a more conservative approach. ¹² The authors suggest that preventative strategies, such as meticulous handling of the catheter and avoidance of removing and reintroducing the needle through the cannula may prevent micro and macroscopic shearing of plastic fragments.

Another incident describes a chemical burn in a child whose back was prepped for the regional anaesthetic using chlorhexidine and alcohol. Following epidural siting, a diathermy plate was affixed to the patient’s back and the patient was positioned supine for surgery. At the completion of surgery, the diathermy plate was removed, and marked redness and blistering were found at the site. This was thought to be a chemical burn caused by prolonged contact with chlorhexidine.

Chlorhexidine-related burns are well described in paediatric literature, but most involve small infants in whom the risk of serious injury is high. ¹⁶ Unfortunately, this minor mishap in an older child resulted in significant harm and serves as a reminder of the risks of everyday surgical preparation. The key tenets of burn risk reduction are well described and should be applied to all children: ¹⁷

application of the minimum amount of chlorhexidine solution;

Local anaesthetic systemic toxicity

Local anaesthetic systemic toxicity is an uncommon, potentially fatal critical incident. There are unique considerations in the paediatric population, and descriptions of such events to this date are limited. In the webAIRS dataset, the authors identified nine possible LAST cases, four of which presented with cardiovascular instability and four with neurological signs. One incident involved both manifestations. All cases involved single injection techniques.

Cardiovascular instability

Cardiovascular instability was defined as significant hypotension or arrest requiring cardiopulmonary resuscitation (CPR). All cases in this series were patients younger than one year of age or less than 10 kg in weight, representing our most fragile paediatric population. Three of the incidents involved neonates, two of whom were ex-premature. All of these incidents involved caudal anaesthesia, the most commonly performed regional technique in the paediatric population. ³

Three of these patients suffered cardiac arrest (two with ventricular tachycardia/fibrillation, one asystolic) requiring CPR. Reporters described additional technical challenges such as extravasation from an intravenous cannula during resuscitation, requiring endotracheal administration of resuscitation drugs and intraosseous needle placement. Fortunately, based on the narratives, all events resolved quickly requiring a maximum of two doses of adrenaline and promptly administered lipid emulsion. The surgery was cancelled in two of the three incidents, with both patients requiring prolonged intubation and ventilation in the paediatric intensive care unit (PICU).

The fourth patient presenting with cardiovascular instability featured hypotension with QRS and ST segment changes. These resolved with calcium and lipid administration. Surgery proceeded uneventfully for this child, and reporters described no significant change in expected outcome.

Paediatric regional anaesthesia is most often performed under general anaesthesia or sedation, with a history of safety supporting this approach. ³ However, lack of direct patient feedback through reported symptoms means that neurological signs and symptoms may be missed, and cardiovascular signs may be the first presentation of LAST. Similarly, awake preverbal or non-verbal children are unable to communicate sensations such as circumoral tingling and tinnitus, complicating early detection and diagnosis. Observed seizure activity with awake regional techniques may yield a quicker diagnosis. ¹⁸ Highlighted in this series is the inherent difficulty with procedures in small, frail infants, particularly during a crisis. Reassuringly, management was prompt, followed established guidelines, and was successful resulting in no documented permanent sequelae.

While regional database studies have not demonstrated a significant correlation between American Society of Anesthesiologists physical status classification and the risk of LAST, ³ the incidents described here all feature infants with medical comorbidities. Infants and neonates also have an inherent propensity to drug toxicity due to physiological immaturity. The overall incidence of LAST in paediatric patients has been estimated to be between 0.7 and six per 10,000, with the highest risk in infants less than 6 months old and with a neuraxial approach. ^{3 , 4 , 19} Paediatric pharmacology literature identifies several high-risk groups for the development of LAST. ²⁰ Neonates have less than half the amount of alpha-acid glycoprotein of adults, resulting in a higher free fraction of local anaesthetic in plasma.^20,21 Neonatal and infant hepatic metabolic pathways are also immature, contributing to slow clearance. The result is an increased risk of LAST in children under one year of age. Prematurity, cardiac, renal, and hepatic dysfunction reduce metabolism and protein binding, further adding to this risk.

Specific studies of bupivacaine suggest that neonates and infants are more susceptible to central nervous system (CNS) toxicity than adults, ²⁰ thus lower plasma concentrations may produce LAST in this group. Accordingly, a lower maximum dose has been recommended in a recent consensus document. ²¹ A study in healthy adult volunteers demonstrated that higher plasma concentrations of ropivacaine are tolerated compared with bupivacaine, and cardiovascular signs and symptoms are less pronounced. ²² While based on an adult population, this suggests that ropivacaine has a greater safety margin with regard to toxicity than bupivacaine. Controlled studies comparing ropivacaine and bupivacaine have demonstrated equivalent potency, although ropivacaine demonstrates a shorter duration motor block. ²³

Neurological sequelae

A range of neurological symptoms was seen in five incidents. Three patients presented with seizures in the postanaesthetic care unit (PACU).

The first report describes a neonate who received 3 mg/kg of ropivacaine by caudal epidural injection while under general anaesthetic. While awake in the recovery room, approximately 45 minutes after the caudal injection, the baby began to seize. A total of four seizures occurred, each around 30 seconds duration. Two doses of lipid emulsion and a dose of midazolam were administered during this time, with successful termination of seizure activity. Investigations were normal and no further seizure activity occurred. A second case involved an upper limb block in a young patient taking antidepressant medication. While in the recovery room, the patient lost consciousness, desaturated and seizure activity occurred. The patient was treated with lipid, midazolam and thiopentone. Further seizures occurred overnight, requiring a phenytoin load (initially avoided due to contraindication in LAST). All investigations including EEG were normal and the patient was reported to be neurologically intact between episodes. Follow-up of the patient revealed ongoing seizures in the community.

An adolescent undergoing dental surgery under general anaesthesia received local infiltration of 1.8 mg/kg ropivacaine and 6.4 mg/kg lignocaine with adrenaline. Two hours post-procedure, the patient had three seizures lasting less than 5 minutes each. This patient was admitted to the PICU for observation, with no further sequelae. The fourth case was a young patient undergoing laparoscopic surgery who received 3.6 mg/kg of ropivacaine during surgical infiltration. In the PACU the patient was notably confused, and the reporter documented the possibility of local anaesthetic CNS toxicity. This patient was observed for two hours, with slow resolution.

The remaining LAST incident presented intraoperatively with combined cardiovascular and neurological symptoms. This incident involved a young patient undergoing an ear, nose and throat procedure. At the completion of surgery, the patient received local infiltration of 1.6 mg/kg ropivacaine 0.75%. The patient became tachycardic and apnoeic with fixed pupils lasting about 5 minutes. Following this, emergence from anaesthesia was prolonged, with apnoea for over 40 minutes. The reporter described the patient as neurologically appropriate following emergence and recovery was uneventful. Lipid was available but not given.

Clinical signs can be non-specific and differential diagnoses broad; physiological derangement related to the patient, surgery or anaesthetic technique should be excluded. Postoperative neurological signs can occur due to reversible or transient sequelae such as emergence delirium, drug toxicity, syncope, metabolic and cerebral pathology or manifestations of mental health conditions. In young patients, surgery may be the first encounter with medical services. Anaesthesia may uncover a new diagnosis, for example, epilepsy, given the propensity of commonly used agents to reduce seizure threshold. The perioperative process may challenge patients with mental health conditions, given the high levels of stress associated with this time. The initial diagnosis of LAST may affect treatment possibilities in the short-term (i.e. choice of anticonvulsants). In all cases, further history, investigations and appropriate specialist consultation were sought by the reporters. All patients were managed safely, did not suffer serious sequelae, and were followed up thoroughly by the treating anaesthetist.

Current American Society of Regional Anesthesia (ASRA) and European Society of Regional Anaesthesia (ESRA) guidelines recommend that paediatric doses should not exceed 1 mL/kg for both 0.2% ropivacaine (2 mg/mL) and 0.25% bupivacaine (2.5 mg/mL). ^{21 , 24} Inconsistent dosing was a feature of the incidents reported to webAIRS, with many of the reported cases receiving doses above those recommended. Large database studies ²⁴ also report a wide variation in dosing practice, with 25% of patients receiving local anaesthetic doses higher than recommended. This was most common in the youngest patients and with the use of ropivacaine, and given our similar findings, indicate an area for targeted practice review. ²⁴

Careful administration is equally important. Two patients who received caudal bupivacaine developed the signs of LAST following negative aspiration and during a deliberate pause midway through administration of the dose, highlighting the false-negative potential of a dry aspirate. Nevertheless, these cases highlight the value of slow and incremental injection of local anaesthetic as the intended full dose was not delivered. Test doses are widely promoted for neuraxial anaesthesia and are associated with a reduced complication rate. ²⁴ The use of ultrasonography to confirm anatomy and correct placement of caudal anaesthesia provides added safety. ²⁵ Compared with non-ultrasound guided techniques for paediatric regional anaesthesia, a Cochrane review has shown higher success rates, lower early postoperative pain scores, prolonged duration of analgesia and shorter block procedure times with use of ultrasound. ²⁶ Surgical infiltration features in three cases, and while considered relatively benign, in these incidents involved high concentrations and high volumes. Communication between surgeon and anaesthetist is encouraged to cross-check appropriate dosing.

On a positive note, one reporter described the benefits of an in situ simulation of a LAST crisis a week prior to this incident. The clinical management, including location and dosing of lipid, was described as rapid and effective due to familiarity with the process. A growing body of evidence supports the benefits of integrated simulation education in improving procedural performance, medical knowledge, adherence to life support protocols and teamwork and communication skills (Figure 2). ^18,27,28

OPEN IN VIEWER

Figure 2.

Local anaesthetic systemic toxicity bowtie diagram. LA: local anaesthetic; APLS: advanced paediatric life support; PICU: paediatric intensive care unit; HDU: high dependency unit; CPR: cardiopulmonary resuscitation; LAST: local anaesthetic systemic toxicity.

‘Stop-before-you-block’

There were two cases in which preoperative assessment was incomplete and led to avoidable incidents. The first was an elective orthopaedic lower limb procedure under general and regional anaesthesia. The supervising consultant and trainee visualised the sonoanatomy and successfully administered local anaesthetic. The surgeons then entered the room to mark the limb and it was discovered that the wrong site had been anaesthetised. On reflection, the reporter mentioned the lack of pre-surgical marking, failure to perform a pre-block ‘time-out,’ and the perioperative team not ‘speaking up’ when the block was incorrectly performed as contributing factors.

Diligent use of the World Health Organization surgical safety checklist involving all perioperative team members is part of the process to reduce wrong-site events and other patient or surgery-specific risks. ³¹ Surgical site marking should occur prior to the patient entering the operating theatre. A patient ‘sign-in’ process should occur prior to the administration of anaesthesia, reviewing the correct operative site and procedure with the consent documentation, with the patient or caregiver present to confirm this.

Specific to regional anaesthesia, a ‘stop-before-you-block’ process is recommended by expert groups and anaesthesia training bodies for all unilateral techniques. ³² This final check is completed with the anaesthetist, their assistant and other available theatre staff. This is performed alongside consent documentation, with visualisation of the surgical site marking just before needle meets skin.

Active followership and ‘speaking up’ may be limited in the theatre environment for a range of reasons. Lack of a shared mental model, limited psychological safety and differing cultural norms around communication feature commonly. Solutions to dismantle the above include surgical briefing at the commencement of the day. Team introductions and a discussion around clinical objectives and delegation of tasks has been shown to improve team awareness and behaviours including mutual respect.^27,33 Team training and rehearsal of non-technical skills through multidisciplinary simulation may also enhance information sharing and teamwork. ‘Speaking up’ is a complex interaction with potentially high stakes for the speaker and the receiver. Active effort positively to reframe and encourage ‘speaking up’ by using a positive receiver response can strengthen team function and ultimately improve patient safety. ³⁴

The second report describes a complex patient with cerebral palsy, respiratory and musculoskeletal comorbidities for major lower limb surgery. This patient had undergone an elective preoperative assessment with a plan for epidural catheter insertion under general anaesthetic. After induction, blood tests were taken, and an epidural was performed. On checking the blood results intraoperatively, it was noted that the patient’s platelet count was less than 80 × 10⁹/L. The patient was monitored and followed up postoperatively with no neurological sequelae. The reporter of this incident cited the lack of appropriate preoperative investigations as a key contributing factor to this event.

Logistical issues may complicate preoperative assessment. Major paediatric operations are performed in a small number of tertiary centres across Australasia, requiring some patients to travel large distances for clinical assessment and treatment. Clinical notes and investigations may not be easily accessible by referral centres, and additional laboratory investigations may be missed. Prior to major operative procedures in a medically complex patient, thorough medical assessment including investigations are prerequisite to optimise and plan safe care. Preoperative investigations may need to be repeated by the treating anaesthetist and their importance is highlighted here. ³⁵

Limitations

WebAIRS is a voluntary, de-identified incident reporting system. Data are collected by tick-boxes and non-mandatory narrative fields. Quality of data depends on depth of information provided by reporters, which can be incomplete and cannot be retrieved retrospectively. While incident reports are a valuable source of information, they have general limitations. Reports can be subjective and influenced by the views and experiences of the reporter; and can be affected by reporter bias or selective recall. While the authors of this paper aim to provide an objective, useful overview of the incidents, hindsight bias may affect the presentation of information. This paper presents only a snapshot of paediatric regional anaesthesia incidents. As no denominator data are available, it is impossible to provide accurate measures of risk for any identified hazards.