Patrick K. Birmingham

Esophageal intubation: a review of detection techniques.

Although the first reported oral intubation of the human trachea occurred in 1878 (l), the procedure did not become standard practice until many years later. It is now a routinely performed procedure, one of the first techniques to be encountered by the anesthesia trainee. It is performed by individuals of different backgrounds and levels of training in the operating suite, emergency room, intensive care unit, hospital ward, and in the field. However, the frequency of tracheal intubation in modern anesthetic practice belies its importance, and the ability to accurately evaluate proper endotracheal tube position is crucial. A review of various anesthetic-related morbidity and mortality statistics (2-8) indicates that unrecognized esophageal intubation remains a problem, even among anesthesia personnel, a medical population specifically trained in such a procedure. An analysis of anesthetic accidents reported to the Medical Defence Union of the United Kingdom from 1970 to 1978 revealed that nearly half the cases resulting in death or cerebral damage were due to faulty technique (2). The technique most often identified as the source of mishap was tracheal intubation, with inadvertent esophageal tube placement the usual problem (2). Another review of anesthesia-related medical liability claims in the United Kingdom from 1977 to 1982 listed esophageal intubation as a ”main cause” of accidents leading to death or neurologic

twenty-four-hour Pharmacokinetics of Rectal Acetaminophen in Children : an Old Drug with New Recommendations

Background: Rectal acetaminophen is often administered during operation to provide supplemental analgesia or antipyresis in children. Recent studies examining current dose guidelines are limited by short sampling times. The authors extended the drug sampling period to more clearly define acetaminophen pharmacokinetics in children having surgery. Methods: Children (n = 28) were randomized to receive a single dose of 10, 20, or 30 mg/kg rectal acetaminophen after induction of anesthesia. Venous blood samples were taken every 30 min for 4 h, every 60 min for 4 h, and every 4 h for 16 h. Data were analyzed using a mixed‐effects modeling technique (using NONMEM software) to determine the volume of distribution and clearance normalized for bioavailability. Additional models accounted for suppository dissolution followed by acetaminophen absorption. Results: Age, weight, estimated blood loss, volume of intravenous fluid administered, and anesthesia time were similar in the three groups. Most patients did not achieve peak or sustained serum values in the 10–20 micro gram/ml serum concentration range associated with antipyresis. The volume of distribution was 385 ml/kg, and clearance normalized for bioavailability, F, was 5.46 ml [center dot] kg sup ‐1 [center dot] min sup ‐1. Pharmacokinetic models suggest that absorption of acetaminophen is a function of zero‐order dissolution of suppositories and first‐order absorption from the rectum. Suppository dose size also may affect absorption characteristics. Conclusions: The current recommended rectal acetaminophen dose of 10–15 mg/kg yields peak serum concentrations less than the antipyretic serum concentration of 10–20 micro gram/ml. Based on the observed kinetics, the authors recommend that the initial dose should be approximately 40 mg/kg.

Initial and subsequent dosing of rectal acetaminophen in Children : A 24-hour pharmacokinetic study of new dose recommendations

Background Recent studies have determined that an initial rectal acetaminophen dose of approximately 40 mg/kg is needed in children to achieve target antipyretic serum concentrations. The timing and amount of subsequent doses after a 40-mg/kg dose has not been clarified for this route of administration. Based on the authors’ previous pharmacokinetic data, they examined whether a 40-mg/kg loading dose followed by 20-mg/kg doses at 6-h intervals maintain serum concentrations within the target range of 10–20 &mgr;g/ml, without evidence of accumulation. Methods Children (n = 16) received rectal acetaminophen (40 mg/kg) and up to three additional doses of 20 mg/kg at 6-h intervals. Venous blood samples were taken every 30 min for 4 h, then every 60 min for 4 h, and every 4 h for 16 h. The authors assessed whether their published pharmacokinetic parameters predicted the acetaminophen concentrations in the present study. They also assessed their dosing regimen by determining the fraction of time each individual maintained the target concentration. Results All patients received the initial loading dose; 10 of 16 patients received three subsequent doses. Serum concentrations with the initial dose were in the target range 38 ± 25% of the time. With subsequent dosing, the target range was maintained 60 ± 29% of the time. The highest serum concentration with initial or subsequent dosing was 38.6 &mgr;g/ml. Pharmacokinetic parameters from the earlier study predicted the serum concentrations observed for both initial and subsequent doses. Conclusions A rectal acetaminophen loading dose of 40 mg/kg followed by 20-mg/kg doses every 6 h results in serum concentrations centered at the target range of 10–20 &mgr;g/ml. There was large interindividual variability in pharmacokinetic characteristics. There was no evidence of accumulation during the 24-h sampling period.

An evaluation of the efficacy and tolerability of oral tramadol hydrochloride tablets for the treatment of postsurgical pain in children.

In this double-blinded, randomized, multicenter study, we examined analgesic efficacy and tolerability of tramadol in postoperative pediatric patients. Eighty-one postsurgical ASA physical status I and II patients ages 7–16 yr received oral tramadol (approximately 1 or 2 mg/kg) for postoperative analgesia when they were ready to transition from morphine patient-controlled analgesia to oral analgesics. Rescue analgesia consisted of morphine patient-controlled analgesia or an oral equivalent dose of oxycodone. Patients rated their pain just before the administration of tramadol and at regular intervals for 8 h afterwards using the Wong-Baker Faces Pain Rating Scale. The 2-mg/kg group required approximately half as much rescue analgesia as the 1-mg/kg group (P = 0.006). Parents rated the larger dose more favorably. Adverse events were generally mild to moderate in severity (vomiting [10%], nausea [9%], pruritus [7%], rash [4%]) and similar between the two treatment groups. There were no significant changes in hemodynamic variables, respiratory rate, or Spo2 percentages between the two treatment groups or in all patients compared with pretreatment values.

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.

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].

Are caudal blocks for pain control safe in children? an analysis of 18,650 caudal blocks from the Pediatric Regional Anesthesia Network (PRAN) database.

BACKGROUND:The caudal block is the most commonly performed regional anesthesia technique in pediatric patients undergoing surgical procedures, but safety concerns raised by previous reports remain to be addressed. Our main objective in current investigation was to estimate the overall and specific incidence of complications associated with the performance of caudal block in children. METHODS:This was an observational study using the Pediatric Regional Anesthesia Network database. A complication after a caudal block was defined by the presence of at least 1 of the following: block failure, vascular puncture, intravascular test dose, dural puncture, seizure, cardiac arrest, sacral pain, or neurologic symptoms. In addition, if a complication was also coded, the presence of temporary or permanent sequelae was evaluated. Additional exploratory analyses were performed to identify patterns of local anesthetic dosage. RESULTS:Eighteen thousand six hundred-fifty children who received a caudal block were included in the study. The overall estimated incidence (95% confidence interval [CI]) of complications after caudal blocks was 1.9% (1.7%–2.1%). Patients who developed complications were younger, median (interquartile range) of 11 (5–24) months, compared to those who did not develop any complications, 14 (7–29) months, P = 0.001. The most common complications were block failure, blood aspiration, and intravascular injection. No cases of temporary or permanent sequelae were identified leading to an estimated incidence (95% CI) of 0.005% (− % to 0.03%). Four thousand four hundred-six of 17,867 (24.6%; 95% CI, 24%–25.2%) subjects received doses (>2 mg of bupivacaine equivalents/kg) that could be potentially unsafe. CONCLUSIONS:Safety concerns should not be a barrier to the use of caudal blocks in children assuming an appropriate selection of local anesthetic dosage.

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.

Transversus Abdominis Plane Block in Children: A Multicenter Safety Analysis of 1994 Cases from the Pran (pediatric Regional Anesthesia Network) Database

BACKGROUND:Currently, there is not enough evidence to support the safety of the transversus abdominis plane (TAP) block when used to ameliorate postoperative pain in children. Safety concerns have been repeatedly mentioned as a major barrier to performing large randomized trials in children. The main objective of the current investigation was to determine the incidence of overall and specific complications resulting from the performance of the TAP block in children. In addition, we evaluated patterns of local anesthetic dosage selection in the same population. METHODS:This was an observational study using the Pediatric Regional Anesthesia Network database. A complication from the TAP block was defined by the presence of at least one of the following intraoperative and/or postoperative factors: puncture of the peritoneum or organs, vascular puncture, cardiovascular, pulmonary and/or neurological symptoms/signs, hematoma, and infection. Additional analyses were performed to identify patterns of local anesthetic dosage. RESULTS:One thousand nine hundred ninety-four children receiving a TAP block were included in the analysis. Only 2 complications were reported: a vascular aspiration of blood before local anesthetic injection and a peritoneal puncture resulting in an overall incidence of complications (95% CI) of 0.1% (0.02%–0.3%) and a specific incidence of complications (vascular aspiration or peritoneal puncture) of 0.05% (0.0054%–0.2000%). Neither of these complications resulted in additional interventions or sequelae. The median (95% range) for the local anesthetic dose per weight for bilateral TAP blocks was 1.0 (0.47–2.29) mg of bupivacaine equivalents per kilogram; however, subjects’ weights were not sufficient to explain much of the variability in dose. One hundred thirty-five of 1944 (6.9%; 95% CI, 5.8%–8.1%) subjects received doses that could be potentially toxic. Subjects who received potentially toxic doses were younger than subjects who did not receive potentially toxic doses, 64 (19–100) months and 108 (45–158) months, respectively (P < 0.001). CONCLUSIONS:The upper incidence of overall complications associated with the TAP block in children was 0.3%. More important, complications were very minor and did not require any additional interventions. In contrast, the large variability of local anesthetic dosage used can not only minimize potential analgesic benefits of the TAP block but also result in local anesthetic toxicity. Safety concerns should not be a major barrier to performing randomized trials to test the efficacy of the TAP block in children as long as appropriate local anesthetic dose regimens are selected.