Shortcomings of this informative study include the lack of direct evidence in proving that the presence of influenza in the upper respiratory tract is directly associated with the infiltrate of the lower respiratory tract. The data may also be skewed because fewer than one-half of the patients with influenza had chest radiographs. The authors’ conclusions demonstrated that clinical findings did not correlate well with radiographically proven infiltrates.—CM
Bradycardia During Methadone Therapy in an Infant
By Lisa Carney, MD
Wheeler AD, Tobias JD. Bradycardia during methadone therapy in an infant. Pediatr Crit Care Med. 2006;7(1):83-85.
This retrospective case report demonstrates the occurrence of bradycardia associated with the use of methadone administered to prevent withdrawal in an infant with physical tolerance following long-term opioid therapy in the PICU setting.
The authors describe the onset of sinus bradycardia in an infant following the initiation of methadone therapy as a transition for intravenous fentanyl administration. The onset of bradycardia was temporally related to standard doses of methadone. These episodes resolved with tactile stimulation. No other pathologic conditions were noted that could have been responsible for the bradycardia. Additionally, the episodes resolved with cessation of methadone therapy. It is unlikely that the bradycardia was merely a manifestation of deep sedation with methadone because the infant’s sedation scores were the same as when he had been receiving fentanyl, a time during which no bradycardia was noted.
When administering opioids, the clinician generally focuses on adverse effects such as respiratory depression, slowing of gastrointestinal motility, and physical dependence. But because methadone’s three-dimensional structure shares similarities with calcium channel antagonists, bradycardia may occur—especially at higher doses. This effect has been reported in the adult literature; however, this is the first report in an infant.
As pediatric hospitalists, we may receive a patient in transfer from the PICU who was recently started on methadone therapy. Given the relatively high frequency of this scenario, it is unclear why bradycardia has not been previously reported in the pediatric population. It may be that the effect was not attributed to methadone and in the majority of cases the slowing of the heart rate was likely to have been innocuous from a physiologic standpoint. What may be more significant is the unnecessary investigation into the etiology of the bradycardia if its relationship to methadone is not appreciated. However, there may be a subset of patients who will not tolerate the bradycardia. Thus, close monitoring is suggested during methadone therapy.
Innoculation Conundrums
Halperin SA, Sweet L, Baxendale D, et al. How soon after a prior tetanus-diphtheria vaccination can one give adult formulation tetanus-diphtheria-acellular pertussis vaccine? Pediatr Infect Dis J. 2006 Mar;25(3):195-200.
Adult tetanus/diphtheria toxoids and acellular pertussis vaccines (Tdap) have been developed to prevent pertussis in adolescents and adults. There are concerns that unacceptable rates of severe injection site reactions, including Arthus-type reactions might occur if Tdap is administered too soon after a previous tetanus/diphtheria toxoid vaccine, such as TD or Td.
This study was conducted via a school-based program where more than 7,000 children/adolescents in grades three-12 were enrolled. These students received Tdap vaccine at intervals from previous vaccination with TD or Td of either 18 months-nine years or greater than/equal to 10 years. The 18 month-nine year interval was further divided into eight cohorts. One cohort per year two to nine (+/- 0.5 years) since receipt of the last TD/Td. Approximately 85% of the students provided accurate documentation of adverse events. There were no serious/major adverse events. There were no differences in reports of fever. Injection site erythema and swelling were slightly and statistically significantly increased with those participants with the most recent prior TD/Td. The increase in these localized injection site events ranged from 3.75%-10.3%.