Perioperative Regional Anesthesia and Pain Scores
Rita Agarwal MD, FAAP, FASA
Original article
Xie J, De Souza E, Perez F, Suárez-Nieto MV, Wang E, Anderson TA. Perioperative Regional Anesthesia Pain Outcomes in Children: A Retrospective Study of 3160 Regional Anesthetics in Routine Practice. Clin J Pain. 2024 Feb 1;40(2):72-81. doi: 10.1097/AJP.0000000000001172. PMID: 37942728.
I am a long-time believer in the power of regional anesthesia at improving pain management and recovery following surgery. In the early days, well before ultrasound, we convinced our surgeons to let us do caudals for lower extremity, perineal and lower abdominal surgery. We convinced our orthopedic surgeons to allow fascia iliacus plane blocks using landmark techniques for femur fractures and other surgery on the femur. It was obvious when those blocks wore off, and we would often do repeat blocks on the floor or in the ED. The pain reduction was dramatic, and the surgeons loved it. It seems obvious that good peripheral nerve blocks decreased pain and the use of opioids.
And yet where’s the data? Unfortunately, there is not a lot. Most studies are small and because it is SO obvious that regional is better than no regional, a lot of the studies you find are comparing one type of block to another or comparing different doses, types, or concentrations of local anesthesia. Suresh et al.1 did a systematic review of the literature in 2014, reviewing 73 RCT with 5125 patients and concluded that there were only a few studies that demonstrated a reduction in pain or pain medication use after regional anesthesia and that more studies needed to be done. In 2018, an update by Kendall et al.2 was more positive and found 40 RCT on 2,408 patients (from the years 2013-2017) that showed a decrease in pain and postoperative opioid consumption in most of the studies.
The goal of the current study,3 done by several awesome members of my Department of Anesthesiology at Stanford University, was to see if in real world settings (i.e all comers, getting all sorts of blocks) would regional anesthesia be associated with decreased pain and decreased opioid consumption? Well obviously, the answer is yes, right?......Or maybe not.
Xie et al.3 performed a retrospective cohort study that looked at analgesic outcomes in children after anesthesia at a quaternary care children’s hospital (Lucile Packard Children’s Hospital). It was part of a quality improvement project looking at pain scores and analgesic use in children 18 or under having general, orthopedic, or urologic surgery between 2014-2018. Pain scores and opioid and other analgesic use was recorded for the intraoperative, PACU and inpatient post operative (up to 72 hours) periods. Any patient admitted to the ICU was excluded. Primary procedure, case complexity, history of OSA, BMI > 25, chronic pain or mood disorders were noted. The primary anesthesiologist was recorded and patients were divided into those who received a single shot technique versus those who had a catheter placed. The procedures included were those that could have been done with a regional technique, and either did or did not receive a block.
3160 (28%) of patient received a regional anesthetic technique, 8132 received no block. The vast majority (86%) received a single shot technique. Patients who did not receive a block were included in the analysis if the same procedure had been performed with a block in another patient.
Not surprisingly, intraoperatively and in the immediate post-operative period (in the PACU), the use of opioids was significantly reduced, and pain scores were lower with many patients who had blocks receiving no opioids. Also, not surprisingly, patients who received a single shot block did not have a difference in pain scores or opioid use after the first 24 hours. Somewhat surprisingly, patients with continuous catheters appeared to have no difference in pain scores or opioid consumption after the immediate PACU stay.
This study raises so many questions, the first being why is there no improvement in pain scores and opioid consumption? The authors postulate that the retrospective nature of the study makes it difficult to ensure that the most optimal block for the procedure was chosen, the correct doses and concentration of the local anesthetics were used, and that functional pain scores (such as pain with movement, deep breathing and cough) and outcomes could not be easily measured. They also go on to wonder if the common practice at our institution of using scheduled versus as needed opioids in some situations may account for the lack of differences seen with pain scores and opioid use.
As someone who has practiced inpatient pain management for 30 years, I think part of the challenge in showing clinical differences even with perfect blocks, arises from the fact that children cry. They cry for lots of reasons and if they have just had a painful surgery, the assumption is usually that they are crying because of pain. Even the best pain scores cannot always account for distress related to other causes. The mean age of all the children in this study was 8.5 years. Children at that age often have difficulty differentiating surgical site pain from pain from an IV, cast, hunger, gas, cramps, muscle spasm or something else . Some children may even be distressed by numbness caused by some blocks at a time when they have no surgical site pain. The authors speculate that “clinical practice may fail to maximize the potential benefits of treatments found to be efficacious in a trial setting”. This may be true, but we (and our nurses) often feel like we are between a rock and a hard place. It is of little comfort to tell the family “Well the block is perfect.” They just want their child to stop crying, and if a little opioid helps, then so be it. Our routine practice when stopping a continuous catheter in a patient is to administer a dose of oral opioid and if the patient does well, return to remove the catheter later. For the first 24 hours we use scheduled opioids and then prescribe them as needed.
I asked the authors of the article for their input and am sharing their responses below:
· We don’t want this paper to be used as an excuse by anyone (e.g. surgeons) to not let anesthesiologists offer or provide regional anesthetics to our patients.
· If we have found in controlled trial settings that regional anesthesia provides opioid sparing and analgesic benefits, we should expect similar findings in routine/real world settings… yet our findings suggest the benefit is not nearly as great as in a controlled environment (this actually surprised us). Therefore, our conclusion is that we should further study and refine:
o Who should we offer regional to?
o What regional technique and what dose/concentration/volume of local anesthetic is most effective to offer (this is particularly relevant in children because we may be “dose limited” due to local anesthetic toxicity concerns due to a child’s lower weight)?
o As a pediatric anesthesia community, larger “pragmatic” trials in real world settings to assess the benefits of regional anesthesia are needed.
· This retrospective review did not examine the subset of patients that might have more greatly benefitted from specific regional anesthesia techniques, nor do we account for our institutional practice of continuing to use opioids despite having a catheter in place (and optimizing pain management via the catheter).
I am really curious to hear your thoughts and practices. Do patients with blocks (single shot or continuous) receive additional analgesics at your institution or in your practice? Do they receive opioids? If yes, do they receive as needed PRN, PCA, or scheduled? What do you do when transitioning patients from a regional technique to oral medications? Are we using the right metrics when we look only at pain scores and opioid consumption in children? Are there better metrics? Send your thoughts and comments to Myron who will post in a Friday reader response.
References:
1. Suresh S, Schaldenbrand K, Wallis B, De Oliveira GS, Jr. Regional anaesthesia to improve pain outcomes in paediatric surgical patients: a qualitative systematic review of randomized controlled trials. British journal of anaesthesia 2014;113(3):375-90. (In eng). DOI: 10.1093/bja/aeu156.
2. Kendall MC, Alves LJC, Suh EI, McCormick ZL, De Oliveira GS. Regional anesthesia to ameliorate postoperative analgesia outcomes in pediatric surgical patients: an updated systematic review of randomized controlled trials. Local Reg Anesth 2018;11:91-109. (In eng). DOI: 10.2147/lra.S185554.
3. Xie J, De Souza E, Perez F, Suárez-Nieto MV, Wang E, Anderson TA. Perioperative Regional Anesthesia Pain Outcomes in Children: A Retrospective Study of 3160 Regional Anesthetics in Routine Practice. The Clinical journal of pain 2024;40(2):72-81. (In eng). DOI: 10.1097/ajp.0000000000001172.