Characterization of lymphocyte-rich hepatocellular carcinoma and the prognostic role of tertiary lymphoid structures.

BACKGROUND & AIMS: Lymphocyte-rich hepatocellular carcinoma (LR-HCC) is largely unknown and a rare subtype of HCC with immune-rich stroma. Tertiary lymphoid structures (TLS), frequently observed in LR-HCC, are known to be prognostically significant in various malignancies; however, their significance in HCC remains unevaluated. METHODS: Clinicopathologic data of 191 cases of surgically resected conventional HCC (C-HCC, n = 160) and LR-HCC (n = 31) were retrieved. Immunohistochemistry, multiplex immunofluorescence staining, RNA sequencing and proteomic analysis were conducted. Differences between the subtypes were statistically evaluated. RESULTS: LR-HCC was significantly correlated to larger tumour size, higher Edmondson-Steiner grade, presence of TLS and higher CD3-, CD8- and FOXP3-positive T cell, high PD-1 and PD-L1 expression (p < .001 for all) compared to C-HCC. Patients with LR-HCC exhibited significantly better overall survival (OS) (p = .044) and recurrence-free survival (RFS) (p = .025) than C-HCC. LR-HCC demonstrated TLS signatures with significantly higher proteomic-based immune scores in 14 of 17 types of tumour-infiltrating immune cells. Furthermore, C-HCC with secondary follicles, the most mature form of TLS, exhibited significantly better OS (p = .031) and RFS (p = .033) than those without. Across the global proteome, LR-HCC was well-differentiated from C-HCC and a map of protein-protein interactions between tumour-infiltrating lymphocytes and HCC in tumour microenvironment was completed. CONCLUSION: LR-HCC is clinicopathologically and molecularly distinct and shows better prognosis compared to C-HCC. Also, the presence of secondary follicle can be an important prognostic marker for better prognosis in both LR-HCC and C-HCC.

Generating Detailed Spectral Libraries for Canine Proteomes Obtained from Serum and Urine.

Domestic dogs (Canis lupus familiaris) are popular companion animals. Increase in medical expenses associated with them and demand for extending their lifespan in a healthy manner has created the need to develop new diagnostic technology. Companion dogs also serve as important animal models for non-clinical research as they can provide various biological phenotypes. Proteomics have been increasingly used on dogs and humans to identify novel biomarkers of various diseases. Despite the growing applications of proteomics in liquid biopsy in veterinary medicine, no publicly available spectral assay libraries have been created for the proteome of canine serum and urine. In this study, we generated spectral assay libraries for the two-representative liquid-biopsy samples using mid-pH fractionation that allows in-depth understanding of proteome coverage. The resultant canine serum and urine spectral assay libraries include 1,132 and 4,749 protein groups and 5,483 and 25,228 peptides, respectively. We built these complimentary accessible resources for proteomic biomarker discovery studies through ProteomeXchange with the identifier PXD034770.

Magnetic transferrin nanoparticles (MTNs) assay as a novel isolation approach for exosomal biomarkers in neurological diseases.

BACKGROUND: Brain-derived exosomes released into the blood are considered a liquid biopsy to investigate the pathophysiological state, reflecting the aberrant heterogeneous pathways of pathological progression of the brain in neurological diseases. Brain-derived blood exosomes provide promising prospects for the diagnosis of neurological diseases, with exciting possibilities for the early and sensitive diagnosis of such diseases. However, the capability of traditional exosome isolation assays to specifically isolate blood exosomes and to characterize the brain-derived blood exosomal proteins by high-throughput proteomics for clinical specimens from patients with neurological diseases cannot be assured. We report a magnetic transferrin nanoparticles (MTNs) assay, which combined transferrin and magnetic nanoparticles to isolate brain-derived blood exosomes from clinical samples. METHODS: The principle of the MTNs assay is a ligand-receptor interaction through transferrin on MTNs and transferrin receptor on exosomes, and electrostatic interaction via positively charged MTNs and negatively charged exosomes to isolate brain-derived blood exosomes. In addition, the MTNs assay is simple and rapid (< 35 min) and does not require any large instrument. We confirmed that the MTNs assay accurately and efficiently isolated exosomes from serum samples of humans with neurodegenerative diseases, such as dementia, Parkinson's disease (PD), and multiple sclerosis (MS). Moreover, we isolated exosomes from serum samples of 30 patients with three distinct neurodegenerative diseases and performed unbiased proteomic analysis to explore the pilot value of brain-derived blood protein profiles as biomarkers. RESULTS: Using comparative statistical analysis, we found 21 candidate protein biomarkers that were significantly different among three groups of neurodegenerative diseases. CONCLUSION: The MTNs assay is a convenient approach for the specific and affordable isolation of extracellular vesicles from body fluids for minimally-invasive diagnosis of neurological diseases.

Effective dose of dobutamine in augmenting free flap blood flow during reconstructive surgery of the lower extremity.

Success of surgical free flap transfer depends on achieving and maintaining adequate perfusion across the microvascular anastomosis. The purpose of this prospective study was to determine the optimal infusion rate of dobutamine to augment duplex ultrasound measured blood flow to the tissue flap during surgery.Twenty-one patients undergoing general anesthesia for lower limb reconstructive surgery were recruited. The optimal dobutamine dose was evaluated using the modified Dixon's up-and-down method, starting at 6 µg·kg·min, and then titrated in increments of 1 µg·kg·min.The optimal dose of dobutamine for improving blood flow to the tissue flap was 3.50 ±â€Š0.57 µg·kg·min in 50% of patients. The 95% effective dose of dobutamine calculated by probit analysis was 4.46 µg·kg·min (95% confidence interval: 3.99-7.00 µg·kg·min).The results of our study suggest that a dobutamine infusion rate less than 5 µg·kg·minprovides significant improvement of blood flow to the tissue flap, while minimizing cardiovascular side effects.

Effect of heated humidified ventilation on bronchial mucus transport velocity in general anaesthesia: a randomized trial.

OBJECTIVE: To evaluate the effects of heated humidified ventilation on mucociliary function during general anaesthesia. METHODS: Male patients (ASA physical status 1 or 2), scheduled for elective radical retropubic prostatectomy, were allocated to receive sevoflurane general anaesthesia with conventional or heated humidified ventilation. Bronchial mucus transport velocity was assessed via fibreoptic bronchoscope and methylene blue dye at 3h after induction of anaesthesia. RESULTS: Median (SE) bronchial mucus transport velocity was significantly higher in the heated humidified group (n = 26) than the conventional ventilation group (n = 24) (1.7 [0.3] mm/min vs 0.9 [0.1] mm/min). CONCLUSION: Heated humidified ventilation effectively maintains mucociliary clearance of patients during sevoflurane general anaesthesia.

Palonosetron has superior prophylactic antiemetic efficacy compared with ondansetron or ramosetron in high-risk patients undergoing laparoscopic surgery: a prospective, randomized, double-blinded study.

BACKGROUND: Postoperative nausea and vomiting (PONV) continues to be a major problem, because PONV is associated with delayed recovery and prolonged hospital stay. Although the PONV guidelines recommended the use of 5-hydroxy-tryptamine (5-HT3) receptor antagonists as the first-line prophylactic agents in patients categorized as high-risk, there are few studies comparing the efficacies of ondansetron, ramosetron, and palonosetron. The aim of present study was to compare the prophylactic antiemetic efficacies of three 5HT3 receptor antagonists in high-risk patients after laparoscopic surgery. METHODS: In this prospective, randomized, double-blinded trial, 109 female nonsmokers scheduled for elective laparoscopic surgery were randomized to receive intravenous 4 mg ondansetron (n = 35), 0.3 mg ramosetron (n = 38), or 75 µg palonosetron (n = 36) before anesthesia. Fentanyl-based intravenous patient-controlled analgesia was administered for 48 h after surgery. Primary antiemetic efficacy variables were the incidence and severity of nausea, the frequency of emetic episodes during the first 48 h after surgery, and the need to use a rescue antiemetic medication. RESULTS: The overall incidence of nausea/retching/vomiting was lower in the palonosetron (22.2%/11.1%/5.6%) than in the ondansetron (77.1%/48.6%/28.6%) and ramosetron (60.5%/28.9%/18.4%) groups. The rescue antiemetic therapy was required less frequently in the palonosetron group than the other groups (P < 0.001). Kaplan-Meier analysis showed that the order of prophylactic efficacy in delaying the interval to use of a rescue emetic was palonosetron, ramosetron, and ondansetron. CONCLUSIONS: Single-dose palonosetron is the prophylactic antiemetics of choice in high-risk patients undergoing laparoscopic surgery.

Intraoperative infusion of 0.6-0.9 µg·kg(-1)·min(-1) remifentanil induces acute tolerance in young children after laparoscopic ureteroneocystostomy.

BACKGROUND: Intraoperative infusion of opioids has been associated with increased postoperative pain and analgesic requirements, but the development of tolerance in young children is less clear. This prospective, randomized, double-blinded study was designed to test the hypothesis that the intraoperative administration of remifentanil results in postoperative opioid tolerance in a dose-related manner in young children. METHODS: We enrolled 60 children (aged 1-5 yr) who were undergoing elective laparoscopic ureteroneocystostomy. Patients were randomized and received an intraoperative infusion of 0, 0.3, 0.6, or 0.9 µg·kg·min remifentanil. Postoperative pain was managed by a parent/nurse-controlled analgesia pump using fentanyl. The primary outcome included the total fentanyl consumptions at 24 and 48 h postsurgery. Secondary outcomes were the postoperative pain scores and adverse effects. RESULTS: The children who received 0.6 and 0.9 µg·kg·min remifentanil required more postoperative fentanyl than the children who received saline or 0.3 µg·kg·min remifentanil (all P < 0.001) for 24 h after surgery. The children who received 0.3-0.9 µg·kg·min intraoperative remifentanil reported higher pain scores at 1 h after surgery than the children who received saline (P = 0.002, P = 0.023, and P = 0.006, respectively). No significant intergroup differences in recovery variables were observed, but vomiting was more frequent in the 0.9 µg·kg·min remifentanil group than in the other groups (P = 0.027). CONCLUSIONS: The intraoperative use of 0.3 µg·kg·min remifentanil for approximately 3 h (range: 140-265 min) did not induce acute tolerance, but the administration of 0.6 and 0.9 µg·kg·min remifentanil to young children resulted in acute tolerance for 24 h after surgery in an apparently dose-related manner.

Psychological and behavioral effects of chloral hydrate in day-case pediatric surgery: a randomized, observer-blinded study.

BACKGROUND/PURPOSE: This prospective, randomized, and observer-blinded study was performed to evaluate the effects of oral chloral hydrate on perioperative psychological and behavioral phenomena in children. METHODS: In total, 100 boys (age, 1-5 years) scheduled for day-case unilateral orchiopexy were randomly allocated into 2 groups and orally administered either 40 mg/kg of chloral hydrate (CH group) or placebo (control group) 30 minutes before surgery, followed by assessment of anxiety, induction compliance, emergence delirium, postoperative pain, and maladaptive behavioral changes. RESULTS: Anxiety scores were significantly lower in the CH group compared with the control group (45.7 vs 28.8). The induction compliance of the CH group was better than that of the control group (3.2 vs 4.8). Postoperative sedation was more frequent (62.7% vs 20.4%); however, the incidence of vomiting was lower (2.0% vs 14.3%) in the CH group than in the control group. Postoperative emergence delirium and maladaptive behavior changes were similar between the 2 groups. CONCLUSION: Decreasing preoperative anxiety with oral chloral hydrate improves induction compliance and reduces postoperative pain intensity without delaying recovery in young boys. However, chloral hydrate had little impact on emergence delirium and postoperative maladaptive behavior.

Effect of anesthetic methods on cerebral oxygen saturation in elderly surgical patients: prospective, randomized, observational study.

BACKGROUND: Intraoperative cerebral oxygen desaturation was reported to be associated with postoperative cognitive dysfunction in elderly patients. The effect of the anesthesia method on regional cerebral oxygen saturation (rSO(2)) is still a question under debate. The purpose of this study was to compare the effects of three common anesthesia methods on intraoperative rSO(2) changes in elderly patients. METHODS: In this prospective randomized clinical trial, 87 patients scheduled for elective transurethral prostatectomy were allocated to receive general inhalational anesthesia (GA group, n = 30), spinal anesthesia (SA group, n = 28), or spinal anesthesia plus sedation with midazolam (SA+S group, n = 29). RESULTS: The numbers of patients showing a decrease in rSO(2) below the baseline value were higher in the SA (92.9 %) and SA+S (100 %) groups than in the GA group (33.3 %). The number of patients with a ≥ 50 % decrease in rSO(2) below baseline was greater in the SA+S (31.0 %) group than in the GA (0 %) or SA (3.6 %) group. During surgery, patients subjected to general anesthesia had higher rSO(2) than those with spinal anesthesia. Blood pressures and heart rates were similar in three groups except 5 and 10 min after anesthesia. Intraoperative SpO(2) was higher in the GA group than in the two spinal anesthesia groups. CONCLUSIONS: Spinal anesthesia is associated with more frequent cerebral desaturation than general anesthesia; and it was aggravated when combined with midazolam sedation. The cerebral effects of anesthesia should be considered when managing high-risk elderly patients.

Preoperative comorbidities and relationship of comorbidities with postoperative complications in patients undergoing transurethral prostate resection.

PURPOSE: We retrospectively identified preoperative comorbidities and analyzed the relationship of the comorbidities to postoperative complications in patients treated with transurethral prostate resection. MATERIALS AND METHODS: We reviewed the surgical and clinical records of 1,878 patients who underwent transurethral prostate resection at a single university hospital between January 2006 and December 2009. Variables included preoperative comorbidities, intraoperative data and postoperative complications, including mortality. RESULTS: Only 32.6% of the patients had no observed preoperative comorbidity and the other 67.4% had at least 1. The incidence of comorbidities increased with age (p <0.001). The overall postoperative complication rate was 5.8%. There were 3 deaths for an overall 0.16% 30-day mortality rate. The postoperative complication rate was significantly higher in patients who had a comorbidity preoperatively and were 50 to 59 (p = 0.043), 60 to 69 (p = 0.028) and 70 to 79 years old (p = 0.017). The Charlson comorbidity index was significantly associated with postoperative complications (r(2) = 0.221, p = 0.012). CONCLUSIONS: Almost two-thirds of the patients who underwent transurethral prostate resection had various preoperative comorbidities. The fact that the preoperative comorbidity was significantly related to postoperative complications after transurethral prostate resection should be considered in perioperative management in this population.

Changes of dorsalis pedis artery flow pattern after caudal block in children: observational study using a duplex sonography.

OBJECTIVE: To evaluate the changes of the flow velocity, the volume flow, and the diameter of dorsalis pedis artery using a duplex ultrasonography after caudal block with sevoflurane anesthesia in children. AIM: To know the acute change in peripheral arterial flow patterns of sympathetically blocked lower limbs in anesthetized children. BACKGROUND: Caudal analgesia in combination with general anesthesia may affect the circulatory hemodynamics due to sympatholytic vasodilating effects. METHODS: After approval by the Ethics Committee, we evaluated the changes of peripheral hemodynamics using a duplex ultrasonography before and after a caudal block in sevoflurane-anesthetized children. RESULTS: A caudal block using 0.15% ropivacaine 1.5 ml·kg(-1) significantly altered the arterial flow patterns; increased peak velocity (24%) and volume flow (76%), and the diameter of the dorsalis pedis artery (20%) in children. However, blood pressures and heart rates were not affected significantly by caudal block. CONCLUSIONS: Duplex sonographic measurements indicate that a caudal block changes the flow patterns of the dorsalis pedis artery significantly in the anesthetized children.

Fentanyl-sparing effect of acetaminophen as a mixture of fentanyl in intravenous parent-/nurse-controlled analgesia after pediatric ureteroneocystostomy.

BACKGROUND: Although acetaminophen has been used widely and is well tolerated in children, its efficacy and safety have not been clarified when combined with an opioid in intravenous parent-/nurse-controlled postoperative analgesia. METHODS: Sixty-three children (aged 6-24 months) who had undergone elective ureteroneocystostomies were enrolled in this prospective, randomized, double-blinded study. After the surgery, an analgesic pump was programmed to deliver fentanyl at a basal infusion rate of 0.25 microg.kg(-1).h(-1) and 0.25 microg/kg bolus after a loading dose of 0.5 microg/kg(-1). In the fentanyl-acetaminophen group, acetaminophen was coadministered as a solution mixture at a basal infusion rate of 1.5 mg.kg(-1).h(-1) and 1.5 mg/kg bolus after a loading dose of 15 mg/kg, whereas saline was administered to the fentanyl group. RESULTS: Postoperative pain scores were similar between the two groups. The total dose (micrograms per kilogram per day, mean+/-SD) of fentanyl at postoperative days 1 (8.3+/-3.7 vs. 18.1+/-4.6, P=0.021) and 2 (7.0+/-2.4 vs. 16.6, P=0.042) was significantly less in the fentanyl-acetaminophen group compared with that in the fentanyl group. The incidences of vomiting (16.1 vs. 56.3%, P=0.011) and sedation (9.7 vs. 46.9%, P=0.019) were significantly lower in the fentanyl-acetaminophen group than those in the fentanyl group. CONCLUSIONS: Acetaminophen has significant fentanyl-sparing effects and reduces side effects when combined with fentanyl in intravenous parent-/nurse-controlled analgesia for postoperative pediatric pain management.

Pulmonary edema after da Vinci-assisted laparoscopic radical prostatectomy: a case report.

A 63 year-old man developed sudden pulmonary edema after uneventful robot-assisted laparoscopic radical prostatectomy (RALP) for prostate cancer despite normal preoperative laboratory findings and appropriate anesthetic management. The pulmonary edema was attributed to prolonged (4 hrs) pneumoperitoneum with concomitant high intraabdominal pressure (15-20 mmHg).

Effect of head rotation on overlap and relative position of internal jugular vein to carotid artery in infants and children: a study of the anatomy using ultrasonography.

PURPOSE: The aim of this study was to evaluate the influence of head rotation on the relative anatomy of internal jugular vein (IJV) and carotid artery (CA) in infants and children. MATERIALS AND METHODS: Two hundred pediatric patients (26.5 +/- 23.3 months old) who were undergoing elective surgery were eligible for this consecutive and prospective study. Using 2-dimensional ultrasound, the amount of overlap and the relative position of the 2 vessels were compared between heads in the neutral position and in 90 degrees of rotation. RESULTS: The mean percentage overlap of CA by IJV in the neutral position increased significantly as the head was rotated to the right (23.3% vs 39.2%) and left (35.3% vs 52.8%). The incidence of lateral positioning of IJV to CA decreased significantly when the head was rotated (40% vs 21% in right, 26.5% vs 10.5% in left). The right IJV is associated with less overlap of the CA than the left, regardless of head position. CONCLUSIONS: The head should be kept in as near a neutral position as possible because the overlap increased by head rotation in both sides. In addition, the right IJV should be preferred because of less CA overlap and more lateral positioning than the left.

Effects of epidural fentanyl on speed and quality of block for emergency cesarean section in extending continuous epidural labor analgesia using ropivacaine and fentanyl.

We performed a prospective, randomized, and double-blind study comparing the top-up effects of 2% lidocaine/100 microg fentanyl/epinephrine (n=31) and 2% lidocaine/saline/epinephrine (n=30) when extending an epidural labor analgesia using low-dose ropivacaine and fentanyl. Survival analysis for the sensory blocks to the T4 level showed no statistically significant differences in onset time to T4 between the 2 groups. Onset times (min) to T4-sensory blocks for cold and pinprick were not different between the two groups. However, median maximum sensory level in the lidocaine-fentanyl group (T1 for cold and T2 for pinprick) was significantly higher than that in the lidocaine-saline group (T3 and T4, respectively). The lidocaine-fentanyl group exhibited less visceral pain (6.5% vs. 36.7%), less supplementation of lidocaine (6.5% vs. 43.3%), and less nausea (6.5% vs. 26.7%) compared with the lidocaine-saline group during the intraoperative period. It is concluded that adding fentanyl to 2% lidocaine does not speed up the onset of the block when the onset is tested with cold or sharp pinprick but improves the quality of analgesia with fewer side effects in emergency top-up for cesarean section.

Fentanyl sparing effects of combined ketorolac and acetaminophen for outpatient inguinal hernia repair in children.

PURPOSE: In this prospective, randomized, double-blinded study we sought to evaluate the efficacy and safety of combined use of intravenous ketorolac and acetaminophen in small children undergoing outpatient inguinal hernia repair. MATERIALS AND METHODS: We studied 55 children 1 to 5 years old who were undergoing elective repair of unilateral inguinal hernia. After induction of general anesthesia children in the experimental group (28 patients) received 1 mg/kg ketorolac and 20 mg/kg acetaminophen intravenously. In the control group (27 patients) the same volume of saline was administered. All patients received 1 microg/kg fentanyl intravenously before incision. We also evaluated the number of patients requiring postoperative rescue fentanyl, total fentanyl consumption, pain scores and side effects. RESULTS: Significantly fewer patients receiving ketorolac-acetaminophen received postoperative rescue fentanyl compared to controls (28.6% vs 81.5%). A significantly lower total dose of fentanyl was administered to patients receiving ketorolac-acetaminophen compared to controls (0.54 vs 1.37 microg/kg). Pain scores were significantly higher in the control group immediately postoperatively but eventually decreased. The incidences of sedation use (55.6% vs 25.0%) and vomiting (33.3% vs 10.7%) were significantly higher in controls. CONCLUSIONS: Preoperative intravenous coadministration of ketorolac and acetaminophen is a simple, safe and effective method for relieving postoperative pain, and demonstrates highly significant fentanyl sparing effects in small children after outpatient inguinal hernia repair.

Paracetamol reduces postoperative pain and rescue analgesic demand after robot-assisted endoscopic thyroidectomy by the transaxillary approach.

BACKGROUND: Postoperative pain following endoscopic thyroidectomy, although less severe than after open methods, is still a source of marked discomfort and surgical stress. This clinical trial was conducted to determine if repeated intravenous paracetamol could decrease postoperative pain and rescue analgesic requirements after robot-assisted endoscopic thyroidectomy via the transaxillary approach. MATERIALS AND METHODS: This prospective, randomized, double-blinded, and placebo-controlled study enrolled 124 women 21-60 years of age who were scheduled for elective gasless robot-assisted endoscopic thyroidectomy via the transaxillary approach. The patients were given placebo or 1 g of paracetamol as a 100 ml solution infused over 15 min 1 h before the induction of anesthesia, and then at 6-h intervals for the following 24 h. RESULTS: Postoperative pain scores were significantly lower at 1, 3, 6, and 24 h after surgery in the paracetamol group than in the placebo group. Significantly fewer patients in the paracetamol group received rescue analgesics compared to the placebo group (9.5% vs. 65.6%, respectively). First analgesic time was similar in the two groups. Postoperative nausea (44.3% vs. 22.2%) and vomiting (21.3% vs. 6.3%) were more frequent in the placebo group than in the paracetamol group. Other postoperative side effects, including sedation, confusion, and pruritus, were similar in the two groups. CONCLUSIONS: We concluded that repeated administration of 1 g of intravenous paracetamol over 24 h is easy, effective, safe, and well tolerated for pain management in patients with moderate to severe postoperative pain after gasless robot-assisted endoscopic thyroidectomy performed via the transaxillary approach.

Detection of subclinical CO2 embolism by transesophageal echocardiography during laparoscopic radical prostatectomy.

OBJECTIVES: To document incidences of subclinical embolism in laparoscopic radical prostatectomy with continuous monitoring using transesophageal echocardiography (TEE). METHODS: A total of 43 patients scheduled for elective robotic-assisted laparoscopic radical prostatectomy under general anesthesia were enrolled in this study. A 4-chamber view of 5.0-MHz multiplane TEE was continuously monitored to detect any intracardiac bubbles as an embolism. An independent TEE specialist reviewed the tapes for interpretation, and emboli were classified as 1 of 5 stages. Cardiorespiratory instability during gas emboli entry was defined as an appearance of cardiac arrhythmias, sudden decrease in mean arterial blood pressure >20 mm Hg, or an episode of pulse oximetric saturation <90%. RESULTS: Gas embolisms were observed in 7 of 41 (17.1%) patients during transection of the deep dorsal venous complex. Of them, 1, 3, 1, and 2 showed stage I, II, III, and IV, respectively. However, there were no signs of cardiorespiratory instability associated with emboli. The 95% confidence interval for gas embolism was 0.204%-0.138%. No correlation was observed between episodes of gas embolism and blood gas variables or end-tidal CO(2) partial pressure. CONCLUSIONS: Subclinical gas embolisms occur in 17.1% of laparoscopic radical prostatectomies. We should consider that this procedure has a potential for serious gas embolism, especially with the increasing popularity of laparoscopic prostatectomy using robot-assisted techniques.

A comparison of high volume/low concentration and low volume/high concentration ropivacaine in caudal analgesia for pediatric orchiopexy.

BACKGROUND: It is unclear whether the volume or concentration of local anesthetic influences its spread and quality of caudal analgesia when the total drug dose is fixed. METHODS: We performed this study in a prospective, randomized, observer-blind manner. Children aged 1-5 yr received a constant dose of 2.25 mg/kg of ropivacaine prepared as either 1.0 mL/kg of 0.225% (low volume/high concentration [LVHC], n = 37) or 1.5 mL/kg of 0.15% solution (high volume/low concentration [HVLC], n = 36). Both solutions contained radiopaque dye. RESULTS: The median spread levels with ranges in the HVLC group (confirmed by fluoroscopic examination) were significantly higher (T6, T3-11) than in the LVHC group (T11, T8-L2). There were no significant differences in recovery times, postoperative pain scores, or side effects between the two groups. After discharge, fewer children in the HVLC group required rescue oral acetaminophen compared with the LVHC group (50.0% vs 75.7%). First oral acetaminophen time was found to be significantly longer with HVLC patients than LVHC patients (363.0 min vs 554.5 min). CONCLUSIONS: We confirmed (with fluoroscopy) that a caudal block with 1 mL/kg ropivacaine spreads to T11 and to T6 with 1.5 mL/kg. If the total dose is fixed, caudal analgesia with a larger volume of diluted ropivacaine (0.15%) provides better quality and longer duration after discharge than a smaller volume of more concentrated ropivacaine (0.225%) in children undergoing day-case orchiopexy. The spread level of ropivacaine correlated significantly with the first oral acetaminophen time after discharge.