Combined spinal/caudal catheter anesthesia: extending the boundaries of regional anesthesia for complex pediatric urological surgery.

BACKGROUND: Spinal anesthesia (SA) is an established anesthetic technique for short outpatient pediatric urological cases. To avoid general anesthesia (GA) and expand regional anesthetics to longer and more complex pediatric surgeries, the authors began a program using a combined spinal/caudal catheter (SCC) technique. STUDY DESIGN: The authors retrospectively reviewed the charts of all patients scheduled for surgery under SCC between December 2016 and April 2018 and recorded age, gender, diagnosis, procedure, conversion to GA/airway intervention, operative time, neuraxial and intravenous medications administered, complications, and outcomes. The SCC technique typically involved an initial intrathecal injection of 0.5% isobaric bupivacaine followed by placement of a caudal epidural catheter. At the discretion of the anesthesiologist, patients received 0.5 mg per kilogram of oral midazolam approximately 30 min prior to entering the operating room. One hour after the intrathecal injection, 3% chloroprocaine was administered via the caudal catheter to prolong the duration of surgical block. Intra-operative management included either continuous infusion or bolus dosing of dexmedetomidine, as needed, for patient comfort and to optimize surgical conditions. Prior to removal of caudal catheter in the post-anesthesia care unit, a supplemental bolus dose of local anesthesia was given through the catheter to provide prolonged post-operative analgesia. RESULTS: Overall, 23 children underwent attempted SCC. SA was unsuccessful in three patients, and surgery was performed under GA. The remaining 20 children all had successful SCC placement. There were 11 girls and nine boys, with a mean age of 16.5 months (3.3-43.8). Surgeries performed under SCC included seven ureteral reimplantations, two ureterocele excisions/reimplantations, two megaureter repairs, four first-stage hypospadias repairs, one distal hypospadias repair, one second-stage hypospadias repair, two feminizing genitoplasties, and one open pyeloplasty. Average length of surgery was 109 min (range 63-172 min). Pre-operative midazolam was given in 13/20 (65%). All SCC patients were spontaneously breathing room air during the operation, and there were no airway interventions. Only one SCC patient received opioids intra-operatively. There were no intra-operative or perioperative complications. DISCUSSION: This pilot study shows that the technique of SCC allows one to do more complex urologic surgery under regional anesthesia than what would be possible under pure SA alone. The main limitations of the study include the relatively small number of patients and the small median length of the operative procedures. As a proof of concept, however, this does show that complex genital surgery bladder level procedures such as ureteral reimplantation can be performed under regional anesthesia. CONCLUSION: SCC allows for more complex surgeries to be performed exclusively under regional anesthesia, thus obviating the need for airway intervention, minimizing or eliminating the use of opioids, and thus avoiding known and potential risks associated with GA. The latter is of particular importance given current concerns regarding hypothetical neurocognitive effects of GA on children aged below 3 years.

Age-Dependent Association Between Pre-transplant Blood Transfusion and Outcomes of Pediatric Heart Transplantation.

Avoidance of red blood cell (RBC) transfusions in patients awaiting heart transplantation (HTx) has been suggested to minimize the risk of allosensitization. Although recent studies have suggested that an immature immune system in younger HTx recipients may reduce risks associated with RBC transfusion, the role of age in moderating the influence of transfusion on HTx outcomes remains unclear. We used available data from a national transplant registry to explore whether the association between pre-transplant transfusions and outcomes of pediatric HTx varies by patient age. De-identified data were obtained from the United Network for Organ Sharing registry, including first-time recipients of isolated HTx performed at age 0-17 years in 1995-2015. The primary exposure was receiving blood transfusions within 2 weeks prior to HTx. Patient survival after HTx was evaluated using multivariable Cox proportional hazards, where age at transplant was interacted with exposure to pre-transplant transfusion. Age-specific hazard ratios (HRs) of pre-transplant transfusion were plotted across ages at transplant. There were 4883 patients meeting inclusion criteria, of whom 1258 died during follow-up (mean follow-up duration 6 ± 5 years). Patients receiving pre-transplant transfusions were distinguished by younger age, higher prevalence of prior cardiac surgery, greater likelihood of being in the intensive care unit, and greater use of left ventricular assist device bridge to transplant. In multivariable analysis, pre-transplant transfusions were associated with increased mortality hazard among infants < 1 year of age (HR = 1.46; 95% CI 1.23, 1.74; p < 0.001). For each additional year of age, the excess hazard associated with pre-transplant transfusions decreased by 3% (interaction HR = 0.97; 95% CI 0.98, 0.99; p = 0.003). By age 8, the association between pre-transplant transfusions and post-transplant mortality was no longer statistically significant (HR = 1.15; 95% CI 0.99, 1.32; p = 0.060). Pre-transplant transfusions were associated with increased mortality hazard only among younger children (age < 8 years) undergoing HTx. These data support the current practices of transfusion avoidance prior to HTx, particularly in younger patients.

Lung Transplant Center Volume Ameliorates Adverse Influence of Prolonged Ischemic Time on Mortality.

The influence of prolonged ischemic time on outcomes after lung transplant is controversial, but no research has investigated ischemic time in the context of center volume. We used data from the United Network for Organ Sharing to estimate the influence of ischemic time on patient survival conditional on center volume in the post-lung allocation score era (2005-2015). The analytic sample included 14 877 adult lung transplant recipients, of whom 12 447 were included in multivariable survival analysis. Patient survival was improved in high-volume centers compared with low-volume centers (log-rank test p = 0.001), although mean ischemic times were longer at high-volume centers (5.16 ± 1.70 h vs. 4.83 ± 1.63 h, p < 0.001). Multivariable Cox proportional hazards regression stratified by transplant center found an adverse influence of longer ischemic time at low-volume centers but not at high-volume centers. At centers performing 50 transplants in the period 2005-2015, for example, 8 versus 6 h of ischemia were associated with an 18.9% (95% confidence interval 6.5-32.7%; p < 0.001) greater mortality hazard, whereas at centers performing 350 transplants in this period, no differences in survival by ischemic time were predicted. Despite longer mean ischemic time at high-volume transplant centers, these centers had favorable patient outcomes and no adverse survival implications of prolonged ischemia.

An evaluation of acid-base changes following aortic cross-clamping using transcutaneous carbon dioxide monitoring.

To investigate the cause of acidosis following release of an aortic cross-clamp, we measured tissue PCO2 using a transcutaneous (TC) CO2 monitor placed below the level of the cross-clamp in 10 patients undergoing aortic arch surgery. Following placement of the aortic cross-clamp, the TC CO2 value from the lower extremity increased from 41 +/- 4 to 92 +/- 41, whereas there was no change in the TC CO2 value from the upper extremity. With release of the cross-clamp, end-tidal CO2 increased by 6.2 +/- 1.9 mmHg, the upper TC CO2 increased by 8.4 +/- 4.8 mmHg, and the lower extremity TC CO2 value returned to baseline. During cross-clamping, there was an increase in the base deficit of 4.3 +/- 2.9 when comparing the baseline arterial blood gas value with the one obtained after cross-clamp release (p = 0.0004). These data demonstrate that the acidosis occurring during aortic cross-clamping is a mixed metabolic and hypercarbic acidosis. Appropriate treatment includes the provision of adequate minute ventilation to ensure CO2 removal and the use of sodium bicarbonate based on the degree of metabolic acidosis demonstrated by arterial blood gas analysis.

Changes in cerebral oximetry during peritoneal insufflation for laparoscopic procedures.

BACKGROUND: Changes in cardiac output may occur during insufflation for laparoscopic procedures. However, there are limited data regarding its potential effects on cerebral oxygenation. MATERIALS AND METHODS: Cerebral oxygenation (ScO(2)), end tidal CO(2), heart rate, blood pressure and oxygen saturation by pulse oximetry were recorded every 5 minutes prior to insufflation, during insufflation and after desufflation. Minute ventilation was increased to maintain normocapnia and the depth of anesthesia was adjusted or fluids/phenylephrine administered to maintain the blood pressure within 20% of the baseline. RESULTS: The cohort for the study included 70 adults for laparoscopic herniorrhaphy, gastric bypass or cholecystectomy. A total of 1004 ScO(2) values were obtained during laparoscopy. The ScO(2) decreased from the baseline in 758 of the 1004 data points. The ScO(2) was 0-9 less than the baseline in 47.8% of the values, 10-19 less than the baseline in 24.9% of the values and 20-29 less than the baseline in 26 values (2.6%). Eighty-two (8.2%) of the values were less than 80% of the baseline value, while 25 values (2.5%) were less than 75% of the baseline value. Twelve patients had at least one ScO(2) value that was less than 80% of the baseline and 6 had at least one ScO(2) value that was less than 75% of the baseline. Four patients of the cohort had ScO(2) values less than 80% of the baseline for more than 50% of the laparoscopic procedure. CONCLUSIONS: Although relatively uncommon, significant changes in cerebral oxygenation do occur in some patients during insufflation for laparoscopic surgery.

Comparison of end-tidal and transcutaneous measures of carbon dioxide during general anaesthesia in severely obese adults.

BACKGROUND: Patients with severe obesity (body mass index (BMI) greater than 35 kg x m(-2)) present difficulties for end-tidal carbon dioxide (FE'(CO(2))) monitoring. Previous studies suggest that transcutaneous (TC) carbon dioxide measurements could be valuable, so we compared FE' and TC measures with Pa(CO(2)) in severely obese patients during anaesthesia. METHODS: We studied patients with severe obesity (BMI >or=40 kg x m(-2)) undergoing gastric bypass surgery. Carbon dioxide was measured with both FE' and TC devices. The difference between each measure (FE'(CO(2)) and TC-CO(2)) and the Pa(CO(2)) was averaged for each patient to provide one value, and data compared with a non-paired, two-way t-test, Fisher's exact test. RESULTS: We studied 30 adults (aged 18-54 yr, mean 41, SD 8.0 yr; weight: 115-267 kg, mean 162, SD 35 kg). The absolute difference between the TC-CO(2) and Pa(CO(2)) was 0.2 (0.2) (mean, SD) kPa while the absolute difference between the FE'(CO(2)) and Pa(CO(2)) was 0.7 (0.4) kPa (P<0.0001). The bias and precision were +0.1 (0.3) kPa for TC vs arterial carbon dioxide and -0.7 (0.4) kPa for FE' vs arterial carbon dioxide. CONCLUSIONS: Transcutaneous carbon dioxide monitoring provides a better estimate of Pa(CO(2)) than FE'(CO(2)) in patients with severe obesity.

Initial experience with octreotide in the pediatric population.

Octreotide is a somatostatin analogue that has been suggested as a therapeutic agent in various diverse disease processes including gastrointestinal bleeding, pancreatitis, hypoglycemia related to hyperinsulin states, and chylous peritoneum/thorax. Despite successful use in the adult population, there is limited information concerning its use in pediatric patients. The authors retrospectively review their experience with octreotide in 10 infants and children ranging in age from 14 days to 17 years. Octreotide, administered by continuous intravenous infusion or intermittent bolus dosing, was used in the treatment of gastrointestinal bleeding in four patients, pancreatitis in three patients, chylous leaks in two patients, and hypoglycemia related to nesidioblastosis in one patient. The clinical course of these patients and the potential therapeutic impact of octreotide are evaluated. Additionally, previous experiences with octreotide in pediatric patients, dosing regimens, and the potential role of the drug in other disease processes are discussed.

Effects of rapacuronium on respiratory function during general anesthesia: a comparison with cis-atracurium.

BACKGROUND: With its introduction for widespread clinical use, there has been an increase in reports of bronchospasm related to the administration of rapacuronium. As it is commonly used for rapid sequence intubation, it has been suggested that these effects may be related to an inadequate depth of anesthesia. The current study examines the airway effects of rapacuronium in tracheally intubated, anesthetized adults. METHODS: Endotracheal intubation was accomplished without the use of neuromuscular blocking agents. Dynamic compliance, tidal volume, peak inspiratory flow rate, peak expiratory flow rate, and peak inflating pressure were measured after administration of either rapacuronium (1.5 mg/kg) or cis-atracurium (0.2 mg/kg) to 20 adult patients (10 received rapacuronium and 10 received cis-atracurium) anesthetized with propofol-remifentanil. RESULTS: Statistically significant increases in peak inflating pressure (22 +/- 6 to 28 +/- 9 cm H2O, P = 0.0012) and decreases in dynamic compliance (108 +/- 43 to 77 +/- 41 ml/cm H2O, P = 0.0001), peak inspiratory flow rate (0.43 +/- 0.11 to 0.39 +/- 0.09 l/s, P = 0.0062), peak expiratory flow rate (0.67 +/- 0.10 to 0.59 +/- 0.09 l/s, P = 0.0015), and tidal volume (744 +/- 152 to 647 +/- 135 ml, P = 0.0293) occurred after administration of rapacuronium. No changes were seen after administration of cis-atracurium. CONCLUSION: These data demonstrate that rapacuronium, but not cis-atracurium, has significant airway effects in intubated, mechanically ventilated adults.

Follow-up survey of children and adolescents with chest pain.

BACKGROUND: The purposes of this study were to identify the outcome of chest pain in children and to identify the incidence of recurrent chest pain and the need for further medical services. METHODS: A telephone survey was conducted of pediatric patients evaluated in the cardiology clinic for chest pain. RESULTS: In the majority of patients (53 of 55), chest pain was thought to be noncardiac in origin. Fifteen patients were offered therapy, and all followed the therapy. Most (10 of 15) thought the therapy was helpful. Forty-one (75%) were satisfied with the explanation given to them. Twenty-six had recurrent chest pain, 12 had pain that was severe, 13 thought the pain interfered with daily activities, and 10 sought further medical care. With the secondary evaluation of chest pain, the diagnosis changed in 9 of 10 cases. CONCLUSION: Chest pain in children is generally benign. However, chest pain can be recurrent and severe, interfering with activities of daily life.

Mechanical ventilation during pregnancy using a helium-oxygen mixture in a patient with respiratory failure due to status asthmaticus.

The authors present a 15-year-old with a second trimester intrauterine pregnancy who developed respiratory failure as the result of status asthmaticus and the development of the adult respiratory distress syndrome. Mechanical ventilation was provided with a combination of oxygen and helium to facilitate gas exchange and limit peak inflating pressures. The physiologic basis for helium's potential beneficial effects on gas exchange are reviewed. Previous reports concerning the use of helium during mechanical ventilation as well as the techniques of delivery are discussed.

Venous air embolism during endoscopic strip craniectomy for repair of craniosynostosis in infants.

BACKGROUND: Various studies have reported an incidence of venous air embolism (VAE) as high as 82.6% during surgical procedures for craniosynostosis. There has been an increase in the use of minimally invasive, endoseopie surgical procedures, including applications for endoscopic strip craniectomy. The current study prospectively evaluated the incidence of VAF during endoscopic strip craniectomy. METHODS: Continuous, intraoperative monitoring for VAE was performed using precordial Doppler monitoring. A recording was made of the Doppler tones and later reviewed to verify its accuracy. RESULTS: The cohort for the study included 50 consecutive neonates and infants ranging in age from 3.5 to 36 weeks and ranging in weight from 3 to 9 kg. Surgical time varied from 31 to 95 min for a total of 2,701 mm of operating time, during which precordial Doppler tones were auscultated. In 46 patients, there was no evidence of VAE. In four patients, there was a single episode of VAE. Two of the episodes of VAE were grade I (change in Doppler tones), and two were grade H (change in Doppler tones and decrease in end-tidal carbon dioxide). No grade III (decrease in systolic blood pressure by 20% from baseline) VAF was noted. CONCLUSION: In addition to previously reported benefits of decreased blood loss, decreased surgical time, and improved postoperative recovery time, the authors noted a low incidence of VAF during endoscopic strip craniectomy in neonates and infants.

Anaesthetic management and high frequency oscillatory ventilation.

In an effort to decrease morbidity and mortality, newer modes of mechanical ventilation have been introduced into the critical care arena. One such technique, high frequency oscillatory ventilation (HFOV) relies on respiratory rates greater than 150 b.min-1, small tidal volumes, and the maintenance of a constant distending pressure thereby limiting peak inflating pressure and potentially the incidence of barotrauma. Despite the frequent application of this technique in the ICU setting, there is limited information concerning its intraoperative use. We present three infants who represent the perioperative applications of HFOV: (i) elective preoperative use to minimize lung movement and interference with surgical exposure during thoracotomy and PDA ligation; (ii) intraoperative application when progressive alterations in respiratory compliance led to ineffective intraoperative ventilation/oxygenation; and (iii) anaesthetic care for a neonate already receiving HFOV. The techniques of HFOV and previous reports of perioperative use are reviewed.

Rapacuronium administration to patients receiving phenytoin or carbamazepine.

Patients receiving anticonvulsants such as phenytoin or carbamazepine may be resistant to neuromuscular blocking agents. The authors report the response to rapacuronium bromide (1.5 mg/kg) in two adult patients; one receiving phenytoin and the other receiving carbamazepine. In both patients, there was a delay in achieving maximum blockade; 100% depression of the first twitch was never achieved in the patient receiving phenytoin. Recovery of neuromuscular function was rapid. In the patient receiving phenytoin and carbamazepine respectively, the clinical duration (time to return of T1% to 25% of baseline) was 5 and 9 minutes, the recovery index (T1 25%-75%) was 4 minutes and 3 minutes, and the time to return of T4/T1 to greater than 0.7 was 15 minutes and 18 minutes 40 seconds. As has been reported with other neuromuscular blocking agents of the aminosteroid class, the clinical duration and the recovery index of rapacuronium are shortened in patients receiving either phenytoin or carbamazepine.

Bupropion overdose in an adolescent.

Bupropion is a relatively new monocyclic antidepressant whose mechanism of action remains unknown. In addition to its use as an antidepressant, it has also been suggested to be effective in children with attention deficit hyperactive disorder and more recently as an aid in the cessation of cigarette smoking. The latter indication has resulted in an increase in its use and therefore an increased availability in households. To date, reports of overdoses in pediatric patients are limited. We report a 14-year-old boy who ingested 1.5 to 3 g of bupropion in a suicide attempt. Previous reports of bupropion ingestions and its management are discussed.

Tolerance during sedation in a pediatric ICU patient: effects on the BIS monitor.

The authors demonstrate the effects of tolerance as measured using the bispectral index (BIS) monitor. Over a 5-day period, there was a twofold increase in the dose of midazolam and a threefold increase in the dose of fentanyl required to provide the same level of sedation and the same BIS number in a 9 year old boy receiving sedation during mechanical ventilation.