Outcomes for 41 260 pediatric surgical patients with opioid-free anesthesia: One center's experience.

BACKGROUND: Opioid use is common and associated with side effects and risks. Consequently, analgesic strategies to reduce opioid utilization have been developed. Regional anesthesia and multimodal strategies are central tenets of enhanced recovery pathways and facilitate reduced perioperative opioid use. Opioid-free anesthesia (OFA) protocols eliminate all intraoperative opioids, reserving opioids for postoperative rescue treatment. Systematic reviews show variable results for OFA. METHODS: In a series of Quality Improvement (QI) projects, multidisciplinary teams developed interventions to test and spread OFA first in our ambulatory surgery center (ASC) and then in our hospital. Outcome measures were tracked using statistical process control charts to increase the adoption of OFA. RESULTS: Between January 1, 2016, and September 30, 2022, 19 872 of 28 574 ASC patients received OFA, increasing from 30% to 98%. Post Anesthesia Care Unit (PACU) maximum pain score, opioid-rescue rate, and postoperative nausea and vomiting (PONV) treatment all decreased concomitantly. The use of OFA now represents our ambulatory standard practice. Over the same timeframe, the spread of this practice to our hospital led to 21 388 of 64 859 patients undergoing select procedures with OFA, increasing from 15% to 60%. Opioid rescue rate and PONV treatment in PACU decreased while hospital maximum pain scores and length of stay were stable. Two procedural examples with OFA benefits were identified. The use of OFA allowed relaxation of adenotonsillectomy admission criteria, resulting in 52 hospital patient days saved. Transition to OFA for laparoscopic appendectomy occurred concomitantly with a decrease in the mean hospital length of stay from 2.9 to 1.4 days, representing a savings of >500 hospital patient days/year. CONCLUSIONS: These QI projects demonstrated that most pediatric ambulatory and select inpatient surgeries are amenable to OFA techniques which may reduce PONV without worsening pain.

An interview with Dr. Anne Marie Lynn, a pioneering woman in medicine.

Dr. Anne Marie Lynn (1949-present), Professor Emeritus of Anesthesiology, Pain Medicine, and Pediatrics at the University of Washington, Seattle, was one of the most influential women in pediatric anesthesiology of her generation. Dr. Lynn embodies the spirit of discovery and advancement that have created the practice of pediatric anesthesiology as we know it today. A pioneer in pain medicine pharmacology, particularly morphine and ketorolac, her research transformed pediatric anesthesia, pediatric pain medicine, and pediatric intensive care medicine. Through her journal articles, book chapters, national and international lectures, mentoring of residents, fellows, and faculty, and leadership in the Society for Pediatric Anesthesia, she inspired a generation of women and men physicians by demonstrating that gender should not be a barrier to undertaking roles once only held only by men. In 2017, for her many contributions, she was awarded the Society for Pediatric Anesthesia's Myron Yaster lifetime achievement award.

Complications in Pediatric Regional Anesthesia: An Analysis of More than 100,000 Blocks from the Pediatric Regional Anesthesia Network.

WHAT WE ALREADY KNOW ABOUT THIS TOPIC: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Complications in pediatric regional anesthesia are rare, so a large sample size is necessary to quantify risk. The Pediatric Regional Anesthesia Network contains data on more than 100,000 blocks administered at more than 20 children's hospitals. This study analyzed the risk of major complications associated with regional anesthesia in children. METHODS: This is a prospective, observational study of routine clinical practice. Data were collected on every regional block placed by an anesthesiologist at participating institutions and were uploaded to a secure database. The data were audited at multiple points for accuracy. RESULTS: There were no permanent neurologic deficits reported (95% CI, 0 to 0.4:10,000). The risk of transient neurologic deficit was 2.4:10,000 (95% CI, 1.6 to 3.6:10,000) and was not different between peripheral and neuraxial blocks. The risk of severe local anesthetic systemic toxicity was 0.76:10,000 (95% CI, 0.3 to 1.6:10,000); the majority of cases occurred in infants. There was one epidural abscess reported (0.76:10,000, 95% CI, 0 to 4.8:10,000). The incidence of cutaneous infections was 0.5% (53:10,000, 95% CI, 43 to 64:10,000). There were no hematomas associated with neuraxial catheters (95% CI, 0 to 3.5:10,000), but one epidural hematoma occurred with a paravertebral catheter. No additional risk was observed with placing blocks under general anesthesia. The most common adverse events were benign catheter-related failures (4%). CONCLUSIONS: The data from this study demonstrate a level of safety in pediatric regional anesthesia that is comparable to adult practice and confirms the safety of placing blocks under general anesthesia in children.

Ultrasound-guided rectus sheath block or wound infiltration in children: a randomized blinded study of analgesia and bupivacaine absorption.

BACKGROUND: Rectus sheath block can provide analgesia following umbilical hernia repair. However, conflicting reports on its analgesic effectiveness exist. No study has investigated plasma local anesthetic concentration following ultrasound-guided rectus sheath block (USGRSB) in children. OBJECTIVES: Compare the effectiveness and bupivacaine absorption following USGRSB or wound infiltration (WI) for umbilical hernia repair in children. METHODS: A randomized blinded study comparing WI with USGRSB in 40 children undergoing umbilical hernia repair was performed. Group WI (n = 20) received wound infiltration 1 mg·kg(-1) 0.25% bupivacaine. Group RS (n = 20) received USGRSB 0.5 mg·kg(-1) 0.25% bupivacaine per side in the posterior rectus sheath compartment. Pain scores and rescue analgesia were recorded. Blood samples were drawn at 0, 10, 20, 30, 45, and 60 min. RESULTS: Patients in the WI group had a twofold increased risk of requiring morphine (hazard ratio 2.06, 95% CI 1.01, 4.20, P = 0.05). When required, median time to first morphine dose was longer in the USGRSB group (65.5 min vs. 47.5 min, P = 0.049). Peak plasma bupivacaine concentration was higher following USGRSB than WI (median: 631.9 ng·ml(-1) IQR: 553.9-784.1 vs. 389.7 ng·ml(-1) IQR: 250.5-502.7, P = 0.002). Tmax was longer in the USGRSB group (median 45 min IQR: 30-60 vs. 20 min IQR: 20-45, P = 0.006). CONCLUSIONS: USGRSB provides more effective analgesia than WI for umbilical hernia repair. USGRSB with 1 mg·kg(-1) 0.25% bupivacaine is associated with safe plasma bupivacaine concentration that peaks higher and later than WI. Caution against using larger volumes of higher concentration local anesthetic for USGRSB is advised.

High-frequency micro-ultrasound for vascular access in young children--a feasibility study by the High-frequency UltraSound in Kids studY (HUSKY) group.

BACKGROUND: Cannulation of small arteries and veins in young children can be challenging. Although anesthesiologists frequently use ultrasound for placement of central venous lines and nerve blocks, its use for cannulation of small, peripheral vessels is less helpful. Ultrasound systems (7-15 MHz) currently used in clinical practice focus poorly at the sub-10-mm space and thus lack the resolution to allow accurate ultrasound-guided cannulation of small vessels. High-frequency micro-ultrasound (HFMU) is a new technology that allows higher resolution (15-50 MHz) compared with conventional ultrasound. Limited human studies have been performed thus far with HFMU, and none have been performed in young children or for vascular access. METHODS: This study was conducted to determine the feasibility of using HFMU to visualize and cannulate peripheral arteries and central veins in children under the age of 6 years old. The diameter of radial and ulnar arteries was also measured. RESULTS: The anesthesiologists involved in this study found the 50 MHz HFMU probe useful for cannulation of peripheral arteries, especially in the youngest children. The higher-frequency probes were less helpful for internal jugular vein cannulation because it was not always possible to view the carotid artery while cannulating the vein. CONCLUSIONS: The experience gained in this feasibility study suggests that HFMU could be a valuable addition to our armamentarium for difficult vascular access in the future.

Morphine distribution in the spinal cord after chronic infusion in pigs.

BACKGROUND: Continuous intrathecal drug delivery provides new options for chronic delivery of drugs that target the spinal cord, but therapeutic efficacy is highly variable. Using an acute porcine model, we have previously demonstrated that continuous intrathecal drug delivery efficacy may be highly variable because of severely limited drug distribution in the cerebrospinal fluid and spinal cord. We designed this study to determine whether the limited drug distribution observed in our acute studies occurs with chronic administration as well. METHODS: Four farm-bred pigs were implanted with intrathecal infusion pumps delivering morphine (1 mg/mL) at 20 µL per hour. Because of a programming error, 1 additional pig received intrathecal morphine at 2 µL per hour. Drug infusion continued for 14 days, during which time animal activity was unrestricted. At the end of 2 weeks the animals were anesthetized and euthanized and their spinal cords removed. The spinal cords were divided into 1-cm sections and morphine concentrations measured. RESULTS: As with previous acute animal studies, drug distribution was extremely limited. Morphine concentration decreased exponentially as a function of distance from the catheter tip, resulting in a 5- to 10-fold decrease over a distance of only 5 to 10 cm. CONCLUSION: Morphine distribution is very limited during chronic intrathecal delivery in ambulatory pigs, and there are significant spinal cord drug concentration gradients as a function of distance from the infusion point. Consequently, catheter tip position may be critical, particularly when infusing isobaric solutions. These data also support the hypothesis that inflammatory masses complicating chronic intrathecal opioid delivery occur at the catheter tip because limited drug distribution results in extremely high drug concentrations at that point.

Predicting lumbar plexus depth in children and adolescents.

BACKGROUND: Lumbar plexus block provides effective analgesia for hip, thigh, and knee surgery. A simple measurement that accurately predicts lumbar plexus depth would be invaluable for clinicians performing this block in children, in whom plexus depth varies with age. METHODS: Surface anatomy measurements were taken on children having lower extremity surgery and lumbar plexus block. All blocks were placed under general anesthesia using peripheral nerve stimulation. The distance from the posterior superior iliac spine (PSIS) to the intercristal line (ICL), i.e., PSIS-ICL distance, and from midline to the intersection of a perpendicular line drawn from the PSIS and the ICL were measured. Lumbar plexus depth was recorded at the point at which maximum quadriceps stimulation was elicited using the lowest current output. Linear regression was used to explore the least squares line of best fit for each measure. RESULTS: Measurements were made on 350 consecutive patients aged 1 month to 24 years. A very strong linear relationship between lumbar plexus depth and PSIS-ICL distance was noted. The median (interquartile range) absolute difference between observed lumbar plexus depth and that predicted by PSIS-ICL distance was 2 mm (1-5 mm), 95% CI for median = 1.36 to 2.64. Ninety-two percent of patients (95% CI, 88.7%-94.6%) had lumbar plexus depths within ±10 mm of the predicted depth. The strongest correlation to lumbar plexus depth was found with PSIS-ICL distance (R(2) = 0.89, P < 0.0001). Weaker correlations were found for weight, height, body mass index, midline-PSIS line distance, and age. CONCLUSION: PSIS-ICL distance provides an accurate, patient-specific predictor for lumbar plexus depth in children over a wide range of age and body habitus. The strong linear relationship obviates the need for complex calculations. This measurement can be used as a guide for ultrasound location, to choose an appropriate needle length, and may reduce complications associated with this block.

Cerebrospinal fluid and spinal cord distribution of hyperbaric bupivacaine and baclofen during slow intrathecal infusion in pigs.

BACKGROUND: Despite the widespread use of implanted pumps for continuous intrathecal drug delivery, there have been no studies aimed at defining the effect of baricity and posture on drug distribution in the cerebrospinal fluid and spinal cord during the very slow infusion rates typically used for chronic intrathecal drug administration. METHODS: Intrathecal microdialysis probes were placed at six points along the neuraxis in both the anterior and posterior intrathecal space of anesthetized pigs to permit cerebrospinal fluid sampling. Animals were then positioned either vertically or horizontally (prone), and a hyperbaric solution containing bupivacaine (7.5 mg/ml) and baclofen (2 mg/ml) was infused at 20 microl/h for 6 h, while the cerebrospinal fluid was collected for measurement of drug concentration. At the end of the experiment, the animals were killed, and the spinal cord was removed and divided into 1-cm sections that were further divided into anterior and posterior portions for measurement of drug concentration. RESULTS: Bupivacaine and baclofen distribution was biased caudally in the vertical group and cephalad in the horizontal group. Drug concentration decreased rapidly in the cerebrospinal fluid and spinal cord as a function of distance from the site of administration in both groups, resulting in most drugs being located in very close proximity to the site of infusion. CONCLUSION: Even at very slow infusion rates, drug distribution within the cerebral spinal fluid and spinal cord are affected by baricity/posture. These findings suggest that patient position and solution baricity may be important clinical factors determining the distribution and ultimate efficacy of chronic intrathecal drug infusions.

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.

Epidural analgesia in a patient with an intrathecal catheter and subcutaneous pump to deliver baclofen.

Baclofen is used for the treatment of spasticity. Small doses administered intrathecally achieve high cerebrospinal fluid concentrations with reduced side-effects. Pediatric anesthesiologists are often reluctant to consider epidural analgesia in children receiving baclofen via an intrathecal catheter and subcutaneous pump. This reluctance is based on concerns for damaging the intrathecal catheter and introducing infection. In addition, the acute cessation of intrathecal baclofen can precipitate a life-threatening withdrawal state. We report a case of successful epidural analgesia in a patient receiving intrathecal baclofen and discuss the steps we took to minimize the chance of harm with this technique. We conclude that an intrathecal catheter and subcutaneous pump to deliver baclofen should not preclude the use of an epidural catheter for perioperative analgesia.