Massive Study Affirms Safety of Pediatric Regional Anesthesia

Author: Michael Vlessides

Anesthesiology News

A multicenter consortium of pediatric anesthesiologists, called the Pediatric Regional Anesthesia Network (PRAN), has concluded that pediatric regional anesthesia is indeed safe.

The study, based on more than 100,000 blocks, found that pediatric regional anesthesia offers a level of safety comparable to that in adults, and also confirmed the safety of placing blocks under general anesthesia in children.

“We just completed the most comprehensive analysis of the Pediatric Regional Anesthesia Network database and published our results in Anesthesiology [2018;129(4):721-732],” said lead author Benjamin J. Walker, MD, an associate professor of anesthesiology at the University of Wisconsin School of Medicine and Public Health, in Madison. “If I had to sum things up in one sentence, it would be this: Pediatric regional anesthesia is—still—safe.”

Unprecedented Data

As Dr. Walker discussed during a symposium at the 2018 annual meeting of the Society for Pediatric Anesthesia, complications in pediatric regional anesthesia are so rare that only a large sample size can accurately quantify the risks associated with the procedures. Enter PRAN, which contains data on regional blocks performed at almost two dozen children’s hospitals across the United States.

The prospective, observational study of routine clinical practice collected data on every regional block for perioperative pain performed or supervised by an anesthesiologist in children younger than 18 years of age at participating institutio ns. The data were uploaded to a secure database and audited at multiple points for accuracy.

The researchers collected various demographic and technical data on patients and related procedures. Adverse events and complications were defined by at least one of the following occurrences:

• neurologic: paresthesia or neurologic deficit
• local anesthetic systemic toxicity: mild or severe
• infection: superficial or deep tissue/abscess
• vascular: hematoma or puncture
• respiratory: pneumothorax, respiratory depression
• catheter malfunction: dislodgement, occlusion
• dural puncture: observation of cerebrospinal fluid or post–dural puncture headache
• other condition

In total, 104,393 blocks were placed in 91,701 patients during the April 1, 2007 to Sept. 30, 2015 study period. The overwhelming majority of the blocks were placed in patients with ASA physical status I to II. The most common procedure recorded was a single-injection caudal block in 38,116 children. Of 45,324 single-injection peripheral nerve blocks, the most common were femoral (n=8,986), sciatic (n=3,263), popliteal (n=2,929) and supraclavicular (n=2,860).

Most Blocks Placed Under General Anesthesia

There were 18,065 continuous catheters placed during the study period, most of which were epidural and caudal catheters (n=13,120). Interestingly, almost all the blocks (93.7%) were placed under general anesthesia. The highest rates of blocks in awake or sedated patients were placed in children aged less than six months or older than 10 years.

“Some people might look at our data and say it’s actually safer to perform blocks under general anesthesia than it is to do awake,” Dr. Walker said. “This, after years of our specialty trying to justify performing blocks under general anesthesia.

“Nevertheless, when we adjusted for various factors, we found that there is actually a slightly higher rate of neurologic complications and toxicity when these blocks are performed awake than under general anesthesia,” Dr. Walker noted. However, the sample size for the awake group was relatively small in comparison, so we believe it is more valid to say that performing blocks under general anesthesia is at least as safe as performing them in awake patients.”

Neurologic complications were exceedingly rare, as only 25 were reported, yielding a complication rate of 2.4 per 10,000 cases (95% CI, 1.6-3.6 per 10,000). The analysis also showed that neurologic complications were more common in children older than 10 years, in whom the incidence was 7.3 per 10,000 cases (95% CI, 5.0-10.7 per 10,000) (P<0.01). No difference was found in risk for neurologic complications between neuraxial (2.0 per 10,000; 95% CI, 1.1-3.7 per 10,000) and peripheral blocks (2.8 per 10,000; 95% CI, 1.6-4.7 per 10,000) (P=0.43).

Although the incidence of neurologic complications with peripheral blocks decreased over time, the researchers noted that use of ultrasound did not affect the overall risk (P=0.98). No differences were found between caudal, lumbar and thoracic blocks in risk for neurologic complications (P=0.41).

Logistic regression analysis found no difference in neurologic complication rates when comparing catheters and single-injection blocks (odds ratio [OR], 0.63; 95% CI, 0.21-2.74; P=0.47) or with local anesthetic concentration more than 0.25% (OR, 2.63; 95% CI, 0.98-8.3; P=0.06).

All reported neurologic complications were largely sensory type; only two children had a sensory deficit beyond three months. No cases of permanent motor deficit were recorded.

In contrast, severe local anesthetic systemic toxicity occurred in seven children (0.76 per 10,000; 95% CI, 0.3-1.6 per 10,000). This event presented as cardiac arrest in four children and seizure in three. All these cases involved local anesthetic bolus dosing, and these events were not observed with continuous infusion techniques. Eleven cases of mild local anesthetic systemic toxicity also occurred; all were reported in the postoperative period and all symptoms resolved after decreasing the rate of local anesthetic infusion or discontinuing the infusion.

“I found it interesting that even though we only had seven cases of severe toxicity, we had 80 positive test doses reported to the database, most of those for epidurals and other neuraxial procedures,” Dr. Walker said. “The test dose has been a controversial subject over the years and has been somewhat muted by the visual test dose many use these days. But it still makes me wonder what might have happened in those 80 cases had a test dose not been used.”

Catheter Duration A Key Indicator

Only one epidural abscess was reported among all cases, in a two-month-old child who underwent a lumbar epidural and subsequently made a full recovery. Moreover, 92 local cutaneous infections were reported in 18,065 continuous catheters (53 per 10,000; 95% CI, 43-64 per 10,000).

No hematomas were reported with neuraxial catheters, and only one was associated with bilateral paravertebral catheters. One pneumothorax occurred in a 2-year-old child who received a single-injection supraclavicular block under ultrasound guidance. Two cases of needle breakage were noted during block placement, without adverse consequences. Finally, one wrong-sided block occurred, a femoral block in a 9-year-old patient.

The study also tracked adverse events. The most common events were catheter complications, which occurred in 4% of cases. Respiratory depression affected 18 children. All of these occurrences were associated with neuraxial catheters (14 per 10,000; 95% CI, 9-22 per 10,000). In 15 of these 18 cases, the epidural infusion contained an opioid. Respiratory depression resolved by pausing or changing the infusion.

Unintentional dural puncture rates were similar in patients undergoing lumbar and thoracic epidural needle insertions (lumbar, 86 per 10,000; thoracic, 66 per 10,000). Not surprisingly, the dural puncture rate among patients receiving caudal needles was 10 per 10,000, significantly lower than either the lumbar or thoracic approaches (P<0.01). Post–dural puncture headache was observed in 11 of the children who experienced dural puncture (7%); seven of them received an epidural blood patch. The overall block failure rate was 1.05%.

Despite the strength of these findings, Dr. Walker noted that the study had limitations. “First and foremost, this is an observational study, which relies on self-report,” he explained. “And even though we audit all reported complications, we can’t audit what’s not reported.” Heterogeneity between centers is another limitation of the study.

Finally, the investigators pointed out that even though pediatric anesthesiologists have made significant inroads with respect to the safety of their practice, more research needs to focus on its benefits. “As operations become less invasive and multimodal regimens improve, we need to ask ourselves if regional practices are having any meaningful and lasting outcomes on our patients,” Dr. Walker said.

“For while we’ve done a lot of work to establish the safety record of pediatric regional anesthesia, we have a lot of work left to do when it comes to quality and outcomes.”