Richard M. Dsida

Patient-controlled Epidural Analgesia in Children: Can They Do It?

Extensive clinical experience and many studies support the use of IV patient-controlled analgesia (IV PCA) and regional anesthesia techniques for the treatment of postoperative pain in children. In contrast, little has been reported about the ability of children to use patient-controlled epidural analgesia (PCEA) or about the efficacy of this technique. We report a descriptive analysis of prospectively recorded data in 128 children (132 procedures) in whom PCEA was used for acute postoperative pain control. Satisfactory analgesia was obtained in 119 patients (90.1%) for up to 103 h with no episodes of desaturation and without clinical evidence of toxicity or serious adverse effects. Analgesia was satisfactory with the initial settings in 89 patients; in 38 others, this was achieved with changes in PCEA settings or solution. Five patients were switched to IV PCA because of inadequate analgesia. Eight patients with satisfactory analgesia were converted to IV PCA because of adverse effects. Children as young as 5 yr had the cognitive ability to understand and the willingness to use PCEA, consistent with reported use of IV PCA. Careful attention should be paid to the total hourly local anesthetic dose to avoid exceeding the recommended limits. Our prospectively collected data demonstrate that PCEA provides satisfactory analgesia with a small incidence of adverse side effects in children and should be considered along with other strategies in pediatric postoperative pain management.

Postoperative hemorrhage after tonsillectomy: use of ketorolac tromethamine.

Recent reports have associated an increased incidence of bleeding after tonsillectomy with the perioperative use of ketorolac tromethamine. To review this association, we examined the hospital and office records of 310 pediatric patients who underwent tonsillectomy with or without adenoidectomy at our institution during a 2-year period. Of these patients, 213 received ketorolac administered as a single dose at the conclusion of the procedure. The remaining 97 patients did not receive ketorolac. The frequency of postoperative hemorrhage was not found to differ significantly between these 2 groups (2.3% vs. 3.1% respectively, P = 0.71). Furthermore, the average time to discharge after surgery was significantly shorter in those patients who received ketorolac than in those who did not (8.5 hours vs. 12.5 hours, respectively, P < 0.0001). The frequency of overnight hospital stays was also significantly lower in those patients who received ketorolac (16.0% vs. 31.6%, respectively, P < 0.01). Concern over the potential for increased hemorrhage after tonsillectomy has led several authors to caution against the use of ketorolac in this setting. In our study, however, the use of ketorolac was not found to increase the incidence of posttonsillectomy hemorrhage and furthermore was associated with a significant decrease in the length of hospital stay as well as a decreased likelihood of overnight hospital stay after surgery.

Age-stratified pharmacokinetics of ketorolac tromethamine in pediatric surgical patients

Published data suggest that ketorolac pharmacokinetics are different in children than in adults. We sought to better characterize ketorolac pharmacokinetics in children. Thirty-six children, aged 1–16 yr, were stratified into four age groups: 1–3 yr, 4–7 yr, 8–11 yr, and 12–16 yr. Each child received 0.5 mg/kg of ketorolac tromethamine IV after completion of elective surgery. A maximum of 16 venous blood samples (mean, 13 ± 2) were collected at predetermined times up to 10 h after drug administration. Plasma ketorolac concentrations were measured by high-performance liquid chromatography after solid-phase extraction. Individual concentration-versus-time relationships were best fit to a two-compartment pharmacokinetic model by using SAAM II. Body weight-normalized pharmacokinetic variables did not differ among the age groups and were similar to those reported for adults, including a volume of distribution at steady state of 113 ± 33 mL/kg (mean ± sd) and an elimination clearance of 0.57 ± 0.17 mL · min−1 · kg−1. Our study demonstrates that a single dose of ketorolac (0.5 mg/kg) results in plasma concentrations in the adult therapeutic concentration range for 6 h in most children. Our data provide no evidence that children require either larger weight-adjusted doses or shorter dosing intervals than adults to provide similar plasma drug concentrations.

Premedication of pediatric tonsillectomy patients with oral transmucosal fentanyl citrate

We assessed the safety and efficacy of oral transmucosal fentanyl citrate (Fentanyl Oralet[registered sign]; Abbott Laboratories, Abbott Park, IL), administered preoperatively to provide both preoperative sedation and postoperative analgesia, in a randomized, double-blind, placebocontrolled study in 40 children, 2-10 yr of age, scheduled for tonsillectomy. In the preoperative holding area, one group (Group O) received Fentanyl Oralet[registered sign] (fentanyl 10-15 micro g/kg), and the other (Group IV) received only the candy matrix. Patients in Group O received an IV injection of saline, and those in Group IV received an IV injection of fentanyl (2 micro g/kg) after removal of the first tonsil. Except for the opioid, patients received a standard anesthetic. Preoperative sedation and cooperation were assessed. Postoperative pain was evaluated using an objective pain scale. Patients in Group O were more sedated but no more cooperative at the induction of anesthesia compared with those in Group IV. No patient vomited preoperatively or experienced preoperative or postoperative desaturation. Time to postanesthesia care unit (PACU) discharge was not different between groups. There was no significant difference in the number of patients requiring morphine in the PACU (6 of 21 in Group O versus 10 of 19 in Group IV). Plasma fentanyl concentrations were not a reliable indicator of the need for postoperative morphine. Among the patients who required morphine postoperatively, there was an 11-fold variation in plasma fentanyl concentrations at the time of morphine administration. Derived pharmacokinetic parameters were similar to those previously reported in children; bioavailability of the fentanyl in Fentanyl Oralet[registered sign] was 0.33. We conclude that premedication with Fentanyl Oralet[registered sign] did not differ with IV fentanyl in regard to the induction of anesthesia and postoperative analgesia. Implications: In this double-blind, randomized study, we studied the efficacy of Fentanyl Oralet[registered sign] (10-15 micro g/kg) preoperatively for providing postoperative analgesia in children undergoing tonsillectomy. We found no incidence of preoperative desaturation or vomiting in any patient. This is in contrast to other studies, in which there was a longer time interval between Fentanyl Oralet[registered sign] completion and induction of anesthesia. The bioavailability of the fentanyl in Fentanyl Oralet[registered sign] was estimated to be 33%, which is less than that reported in adults (approximately 50%). There was no difference in postoperative opioid requirements between patients who received 2 micro g/kg of fentanyl IV and those who received Fentanyl Oralet[registered sign].

Uptake pharmacokinetics of the Fentanyl Oralet® in children scheduled for central venous access removal: implications for the timing of initiating painful procedures

Summary Background: The Fentanyl Oralet® (Abbott Laboratories, Abbott Park, IL, USA) is an oral transmucosal drug delivery system. We previously examined pharmacokinetic parameters of children who had completed consumption of the Fentanyl Oralet®. The present study was designed to clarify pharmacokinetic parameters during the consumption phase to determine if there is an optimal administration time before painful procedures.

Do latex precautions in children with myelodysplasia reduce intraoperative allergic reactions

Children with myelodysplasia have an increased incidence of latex allergy, which can lead to severe intraoperative allergic reactions. Despite widespread recommendations to avoid intraoperative latex exposure, little evidence exists to support the efficacy of this practice. We examined the incidence of intraoperative allergic reactions in children with myelodysplasia who underwent 1,025 operations in a 36-month period before and after institution of a standardized latex-avoidance protocol. Risk factors for an intraoperative reaction were found to be a history of latex allergy (p = 0.001) and surgery performed before institution of the latex-avoidance protocol (p = 0.01). The estimate of increased risk for allergic reaction was 3.09 times higher in cases performed without latex avoidance. Recognized violation of the protocol after its institution led to severe allergic reactions in three patients. Our experience suggests that a latex-avoidance protocol reduces intraoperative allergic reactions in children with myelodysplasia. Development of severe allergic reactions with violation of the protocol reinforces the importance of vigilance on the part of all operating room personnel in its implementation.

Teaching residents pediatric fiberoptic intubation of the trachea: Traditional fiberscope with an eyepiece versus a video-assisted technique using a fiberscope with an integrated camera

Background:The authors’ hypothesis was that a video-assisted technique should speed resident skill acquisition for flexible fiberoptic oral tracheal intubation (FI) of pediatric patients because the attending anesthesiologist can provide targeted instruction when sharing the view of the airway as the resident attempts intubation. Methods:Twenty Clinical Anesthesia year 2 residents, novices in pediatric FI, were randomly assigned to either the traditional group (traditional eyepiece FI) or the video group (video-assisted FI). One of two attending anesthesiologists supervised each resident during FI of 15 healthy children, aged 1–6 yr. The time from mask removal to confirmation of endotracheal tube placement by end-tidal carbon dioxide detection was recorded. Intubation attempts were limited to 3 min; up to three attempts were allowed. The primary outcome measure, time to success or failure, was compared between groups. Failure rate and number of attempts were also compared between groups. Results:Three hundred patient intubations were attempted; eight failed. On average, the residents in the video group were faster, were three times more likely to successfully intubate at any given time during an attempt, and required fewer attempts per patient compared to those in the traditional group. Conclusions:The video system seems to be superior for teaching residents fiberoptic intubation in children.

Determination of ketorolac in human plasma by reversed-phase high-performance liquid chromatography using solid-phase extraction and ultraviolet detection

An improved high-performance liquid chromatographic method has been developed to measure human plasma concentrations of the analgesic nonsteroidal anti-inflammatory drug ketorolac for use in pharmacokinetic studies. Samples were prepared for analysis by solid-phase extraction using Bond-Elut PH columns, with nearly complete recovery of both ketorolac and the internal standard tolmetin. The two compounds were separated on a Radial-Pak C18 column using a mobile phase consisting of water-acetonitrile-1.0 mol/l dibutylamine phosphate (pH 2.5) (30:20:1) and detected at a UV wavelength of 313 nm. Using only 250 microl of plasma, the standard curve was linear from 0.05 to 10.0 microg/ml.

Sodium nitroprusside metabolism in children during hypothermic cardiopulmonary bypass.

Ten children, aged 1-7 yr, presenting for repair of complex congenital heart lesions, were prospectively studied. A ketamine, halothane/isoflurane, and fentanyl anesthetic was used. After initiation of hypothermic cardiopulmonary bypass, sodium nitroprusside (SNP) was titrated as necessary to maintain a target mean arterial blood pressure of 35-60 mm Hg. Blood samples drawn immediately prior to starting SNP infusion, every 15 min during infusion, and at 1, 4, and 24 h postinfusion were analyzed for whole blood cyanide (CN sub.-) and serum thiocyanate (SCN-). Blood gas analysis was performed every 30 min during SNP infusion. A maximum CN- level >or=to1.0 micro gram/mL was observed in two children; four others had maximum CN- levels between 0.5 micro gram/mL and 1.0 micro gram/mL (normal, <0.2 micro gram/mL). No child had a clinically important increase of SCN- subsequent to SNP infusion. There was substantial variability in observed CN- accumulation during SNP infusion. CN- levels during the first 60 min correlated with the average SNP rate of administration (P = 0.02). Cyanide levels rapidly decreased after termination of SNP infusion and were undetectable 4 h postinfusion. Despite the short-term increase of CN- level, no child showed biochemical signs of toxicity (acidosis or increased mixed venous oxygen tension). (Anesth Analg 1995;81:952-6)

Fiberoptic intubation: troubles with the "Tube"?

To the Editor:—Dr. Kristensen has concluded that during intubation with the use of a flexible fiberscope, the use of the Parker Flex-Tube results in a significantly lower rate of repositioning and repeated attempts at passing the tube into the trachea, compared to a standard endotracheal tube. We believe it would be more appropriate to conclude that the Parker tube is better only when the standard tube is improperly oriented during passage. Dr. Kristensen reported that once the standard tube was rotated counterclockwise by 90 degrees, its success rate improved to 26 out of 38 attempts. This was essentially the same as the success rate (27 out of 38 attempts) of the Parker tube and is consistent with our experience with the standard tube. Why not simply start with the standard tube rotated counterclockwise by 90 degrees? The Parker tube requires a higher cuff pressure, which, in our opinion, makes it less desirable. The simple technique of rotating the standard tube counterclockwise by 90 degrees during the first attempt along a fiberoptic bronchoscope has been our standard practice for years, thanks to a suggestion by Katsnelson et al. in 1992. Eighteen years ago, Cossham proposed rotating a standard tube counterclockwise by 90 degrees to facilitate passage along a gum-elastic bougie, and in 1990, Dogra et al. demonstrated convincingly the usefulness of this technique. Granted, this technique may not be widely appreciated, perhaps because the gum-elastic bougie is not used in some parts of the world and the use of fiberoptic bronchoscopy is infrequent. As such, Dr. Kristensens’study should help to popularize this important “trick.”