Safety of pediatric continuous interscalene block catheters placed under general anesthesia: a single center's experience.

BACKGROUND: The use of interscalene catheters is an effective treatment strategy for children and adolescents undergoing shoulder surgery. Although placement of interscalene catheters in the awake child is challenging, some have cautioned against performing regional anesthesia in the patient under general anesthesia. We present a case series of 154 interscalene catheters placed in pediatric patients under general anesthesia and managed in the outpatient setting. METHODS: A total of 154 interscalene catheters were placed at a single institution between April 2006 and December 2011 using a modified lateral approach. All catheters were placed with the patient under general anesthesia. The patients discharged home with the catheters were followed-up with daily phone calls until removal of the catheter. RESULTS: Of the 154 patients with an interscalene CPNB, 132 (85.7%) were discharged home with the interscalene CPNB in place. The success rate for the catheters was 92.1% (CI: 86.9-95.7%). The most common reason for catheter failure (6%) was early dislodgement (within 24 h). In addition to these 12 patients, 3 other patients had adverse events related to the interscalene CPNB. CONCLUSION: Interscalene catheter placement under general anesthesia and management on an outpatient basis is feasible in the pediatric population and is associated with a low rate of catheter-related complications.

Pain management following the Nuss procedure: a survey of practice and review.

BACKGROUND: Pectus excavatum is the most common congenital chest wall deformity. The Nuss procedure is frequently used for surgical correction and this technique has been associated with severe and prolonged post-operative pain. At the present time, the optimal analgesic strategy for managing patients following this procedure has not been determined. METHODS: A web-based survey was sent to representatives from 108 primarily pediatric hospitals in North America, Europe, Asia and Australia. One individual per institution was contacted to complete the survey on behalf of their department. RESULTS: Survey response rate was 54% and 55 institutions reported using the Nuss procedure for correction of pectus excavatum. Annual case volume is less than or equal to 25 cases in 57% of institutions, and the most common age of patients is 14 to 17 years old. A clinical protocol for patient post-operative pain management is used in 45% of institutions. Thoracic epidural is utilized as a primary analgesic modality by 91% of institutions. Concomitant use of intravenous patient-controlled analgesia is reported by 27% of institutions. Nine respondents (16%) reported that they had recently stopped performing epidurals because of surgeon preference. Referral of one or more patients annually for chronic pain management was reported in 22% of surveys. CONCLUSIONS: Post-operative pain management following the Nuss procedure is variable and poorly characterized. Clinical trials or large observational registries comparing the safety and efficacy of primary modalities and long-term outcomes are needed to enable evidence-based decision-making for the management of these patients.

Sonoanatomy of the vasculature at the supraclavicular and interscalene regions relevant for brachial plexus block.

BACKGROUND: Our aim in this observational study was to utilize ultrasound, as well as anatomic dissection, to document the frequency with which branches of the subclavian vessels are found in close association with the brachial plexus at the locations of supraclavicular and interscalene brachial plexus block. METHODS: Ultrasound was utilized to document the presence of branches of the subclavian vein and artery, adjacent to the brachial plexus in the supraclavicular and in the interscalene region in 50 patients undergoing shoulder surgery. The position, depth, and dimensions of the vessels were described, and the origin determined when possible. In addition, the posterior triangle of the neck on both sides of three non-preserved cadavers was dissected to evaluate the vascular anatomy and correlate the ultrasound findings. RESULTS: Ultrasound scanning revealed an arterial branch adjacent to, or passing directly through, the brachial plexus in the supraclavicular region in 43/50 (86%) patients. Within the interscalene region, an artery was identified coursing in a lateral direction in 45/50 (90%) of cases, while a corresponding small vein, coursing medial to lateral in this area, was noted in 23/50 (46%) of cases. CONCLUSIONS: Small branch vessels from the subclavian artery and vein were frequently evident, on ultrasound imaging, in close association with the nerve elements of the brachial plexus in the supraclavicular and interscalene regions. Appreciation of the presence of these vessels and their likely origin and course will aid the anesthesiologist in planning a safe nerve block.

Ultrasound evaluation of the anatomy of the vessels in relation to the femoral nerve at the femoral crease.

PURPOSE: We conducted this prospective, observational study using ultrasound to describe the neuro-vascular relationships at the femoral crease. In particular, we sought to identify and describe the incidence of vascular structures lying lateral to the femoral artery at this level, and the frequency with which needle insertion would require adjustment to avoid contact with these vessels during femoral nerve blockade (FNB). METHODS: Twenty-five patients undergoing surgery on the knee for femoral nerve block were scanned with ultrasound in the femoral triangle region to evaluate the anatomy of the vessels in this region. Specifically, the position and course of the profunda femoral and lateral circumflex arteries, and their relationship to the site of typical FNB, were described. Depth and dimensions of the vessels and nerves were recorded. The patients' body mass indices and the depth of the femoral nerve were evaluated for correlation. RESULTS: In 52% of the cases, the profunda femoral artery coursed lateral to the femoral artery, while in the others, it remained deep to the femoral artery. The profunda femoral artery emerged from the femoral artery above the femoral crease in 12% of the cases, and below it in the remainder, while the lateral circumflex femoral artery emerged above the crease in 8% of the patients. The site of needle insertion for FNB was adjusted to avoid vessels lateral to the femoral artery in 12% of the cases. CONCLUSION: Ultrasound scanning at the femoral crease in preparation for FNB reveals branches lying lateral to the main femoral artery in a significant proportion of patients, presenting a significant risk of needle contact with one of these vessels. The use of ultrasound likely reduces the risk of vascular trauma in this setting.

Acute hemodynamic changes after rapid intravenous bolus dosing of dexmedetomidine in pediatric heart transplant patients undergoing routine cardiac catheterization.

BACKGROUND: Dexmedetomidine is a highly selective α(2)-adrenoceptor agonist with sedative, anxiolytic, and analgesic properties that has minimal effects on respiratory drive. Its sedative and hypotensive effects are mediated via central α(2A) and imidazoline type 1 receptors while activation of peripheral α(2B)-adrenoceptors result in an increase in arterial blood pressure and systemic vascular resistance. In this randomized, prospective, clinical study, we attempted to quantify the short-term hemodynamic effects resulting from a rapid i.v. bolus administration of dexmedetomidine in pediatric cardiac transplant patients. METHODS: Twelve patients, aged 10 years or younger, weighing ≤40 kg, presenting for routine surveillance of right and left heart cardiac catheterization after cardiac transplantation were enrolled. After an inhaled or i.v. induction, the tracheas were intubated and anesthesia was maintained with 1 minimum alveolar concentration of isoflurane in room air, fentanyl (1 µg/kg), and rocuronium (1 mg/kg). At the completion of the planned cardiac catheterization, 100% oxygen was administered. After recording a set of baseline values that included heart rate (HR), systolic blood pressure, diastolic blood pressure, central venous pressure, systolic pulmonary artery pressure, diastolic pulmonary artery pressure, pulmonary artery wedge pressure, and thermodilution-based cardiac output, a rapid i.v. dexmedetomidine bolus of either 0.25 or 0.5 µg/kg was administered over 5 seconds. The hemodynamic measurements were repeated at 1 minute and 5 minutes. RESULTS: There were 6 patients in each group. Investigation suggested that systolic blood pressure, diastolic blood pressure, systolic pulmonary artery pressure, diastolic pulmonary artery pressure, pulmonary artery wedge pressure, and systemic vascular resistance all increased at 1 minute after rapid i.v. bolus for both doses and decreased significantly to near baseline for both doses by 5 minutes. The transient increase in pressures was more pronounced in the systemic system than in the pulmonary system. In the systemic system, there was a larger percent increase in the diastolic pressures than the systolic pressures. Cardiac output, central venous pressure, and pulmonary vascular resistance did not change significantly. HR decreased at 1 minute for both doses and was, within the 0.5 µg/kg group, the only hemodynamic variable still changed from baseline at the 5-minute time point. CONCLUSION: Rapid i.v. bolus administration of dexmedetomidine in this small sample of children having undergone heart transplants was clinically well tolerated, although it resulted in a transient but significant increase in systemic and pulmonary pressure and a decrease in HR. In the systemic system, there is a larger percent increase in the diastolic pressures than the systolic pressures and, furthermore, these transient increases in pressures were more pronounced in the systemic system than in the pulmonary system.

Localization of S100A8 and S100A9 expressing neutrophils to spinal cord during peripheral tissue inflammation.

Investigation of hyperalgesia at the spinal transcriptome level indicated that carrageenan-induced inflammation of rat hind paws leads to a rapid but sustained increase in S100A8 and S100A9 expression, two genes implicated in the pathology of numerous inflammatory diseases including rheumatoid arthritis and gout. In situ hybridization revealed that the elevation occurred in neutrophils that migrate to the spinal cord vasculature during peripheral inflammation, not in spinal neurons or glial cells. Immunohistochemical analysis suggests, but does not prove, that these neutrophils abundantly release S100A8 and S100A9. Consistent with this, we detected an increase in ICAM and VCAM, both indicators of endothelial activation, a known trigger for secretion of S100A8 and S100A9. Migration of S100A8- and S100A9-expressing neutrophils to spinal cord is selective, since MCP-1- and CD68-expressing leukocytes do not increase in spinal cord vasculature during hind paw inflammation. Examination of many neutrophil granule mediators in spinal cord indicated that they are not regulated to the same degree as S100A8 and S100A9. Neutrophil migration also occurs in the vasculature of brain and pituitary gland during peripheral inflammation. Together, these findings suggest an interaction between a subpopulation of leukocytes and the CNS during peripheral tissue inflammation, as implied by an apparent release and possible diffusion of S100A8 and S100A9 through the endothelial blood-brain barrier. Although the present findings do not establish the neurophysiological or behavioral relevance of these observations to nociceptive processing, the data raise the possibility that selective populations of leukocytes may communicate the presence of disease or tissue damage from the periphery to cells in the central nervous system.