Steven G. Rothrock

Inadvertent ketamine overdose in children: Clinical manifestations and outcome

STUDY OBJECTIVE We sought to characterize the clinical manifestations, outcome, and etiology of inadvertent ketamine overdose in the emergency department. METHODS We investigated cases of inadvertent ketamine overdose in children seen in the ED solicited through electronic mail subscription lists or reported to the Institute for Safe Medication Practices. The clinical manifestations, outcome, and reported cause for each case are described. RESULTS We identified 9 cases of inadvertent ketamine overdose in children treated in the ED. Patients received either 5(n=3), 10(n=5), or 100(n=1) times the intended dose, either by the intramuscular (n=5) or intravenous (n=4) route. All 9 experienced prolonged sedation (3 to 24 hours). Four experienced brief respiratory depression shortly after administration, and assisted ventilation was performed in 2. Two children without respiratory difficulty or hypoxemia were intubated by their physicians as a precaution. In 5 children, the dosing error was not discovered until late in the sedation, often when the child was not waking at the expected time. No adverse outcomes were noted, and all children were normal neurologically on discharge and longer-term follow-up if available. CONCLUSION No adverse outcomes were noted in 9 healthy children treated in the ED who inadvertently received 5 to 100 times the intended dose of ketamine. Toxicity manifested as prolonged sedation in all 9 and brief respiratory depression in 4. The margin of safety in ketamine overdose may be wide, although less common and more serious outcomes cannot be excluded by this small, self-reported sample.

Failure of Adjunctive Bicarbonate to Improve Outcome in Severe Pediatric Diabetic Ketoacidosis

STUDY OBJECTIVE Although adjunctive intravenous bicarbonate therapy is commonly recommended for children with severe diabetic ketoacidosis (DKA), no studies assessing clinical outcome with this therapy have ever been performed. Our objective was to determine whether bicarbonate therapy influenced outcome for pediatric DKA. METHODS The study was a retrospective consecutive case series of 147 admissions for severe DKA (initial pH < or = 7.15 and glucose concentration > or = 300 mg/dL [16.7 mmol/L]) in 106 children during a 16-year period at a tertiary university medical center. Descriptive statistics were applied to the 147 admissions. The first patient admitted with DKA was then selected for each of the 106 children, and clinical and laboratory data were compared between subjects who did and did not receive bicarbonate. Multivariate and matched pair analyses were performed to control potentially confounding variables. RESULTS Fifty-seven of the 147 patients admitted with DKA (39%) were successfully treated without bicarbonate, including 9 with a pH of 7.00 or less and one with a pH of 6.73. The frequency of complications was comparable between bicarbonate and nonbicarbonate groups (4% versus 2%, P = 1.00). The mean duration of hospitalization for children receiving bicarbonate was 23% (16 hours) longer than children who did not receive bicarbonate in the multivariate analysis (P = .07) and 37% (22 hours) longer in the matched pair analysis (P = .01). The mean rate of metabolic recovery by three distinct measures was similar between groups, and the sample had 80% power to detect differences of 14% to 29% in these measures. CONCLUSION We found no evidence that adjunctive bicarbonate improved clinical outcome in children with severe DKA. The rate of metabolic recovery and complications were similar in patients treated with and without bicarbonate, and prolonged hospitalizations were noted in the bicarbonate group. We conclude that adjunctive bicarbonate is unnecessary and potentially disadvantageous in severe pediatric DKA.

Misdiagnosis of appendicitis in nonpregnant women of childbearing age

A retrospective case series was conducted at a teaching hospital with an emergency department (ED) census of 100,000 patients per year to identify the incidence of, and factors associated with, the misdiagnosis of appendicitis in nonpregnant women aged 15 to 45 years. There were 174 nonpregnant women identified with a pathologic diagnosis of appendicitis. Clinical features were then compared between patients misdiagnosed (seen in prior 10 days and given an incorrect diagnosis) and those who were initially diagnosed correctly. The results showed that 33% of the women with appendicitis were initially misdiagnosed. The most common misdiagnoses included pelvic inflammatory disease, gastroenteritis, and urinary infections. Misdiagnosed women more frequently exhibited diffuse and bilateral lower abdominal pain and tenderness, cervical motion, and right adnexal tenderness. Misdiagnosed women also had a lower incidence of right lower quadrant pain and tenderness, and peritoneal signs. In addition, misdiagnosis was associated with an increased incidence of perforation, abscess formation, and an increase in the total length of hospitalization. In conclusion, the incidence of misdiagnosis of appendicitis in women of childbearing age is high. Women who are misdiagnosed have less typical symptoms and physical findings and more frequent abnormal pelvic findings than those who are diagnosed correctly. Emergency physicians should be aware that atypical signs and symptoms are associated with misdiagnosed appendicitis in nonpregnant women of childbearing age.

Ketamine sedation for pediatric gastroenterology procedures.

BACKGROUND Although the dissociative sedative ketamine is used commonly for pediatric procedural sedation in other settings, the safety of this agent in pediatric gastroenterology is not well-studied. A 5-year experience with ketamine sedation for pediatric gastroenterology procedures was reviewed to document the safety profile of this agent and to identify predictors of laryngospasm during esophagogastroduodenoscopy (EGD). METHODS The study was a retrospective consecutive case series of children receiving ketamine administered by pediatric gastroenterologists skilled in basic airway management to facilitate pediatric gastrointestinal procedures during a 5-year period. Patients records were reviewed to determine indication, dosage, adverse effects, drugs, inadequate sedation, and recovery time for each sedation. A multiple logistic regression analysis was performed to identify predictors of laryngospasm during EGD. Outcome measures were descriptive features of sedation, including adverse effects and predictors of laryngospasm during EGD. RESULTS During the study period pediatric gastroenterologists administered ketamine 636 times, primarily for EGD (86%) and primarily by the intravenous route (98%). The median loading dose and total dose were 1.00 mg/kg and 1.34 mg/kg, respectively. Inadequate sedation was noted in seven (1.1%) procedures. Adverse effects included transient laryngospasm (8.2%), emesis (4.1%), recovery agitation (2.4%), partial airway obstruction (1.3%), apnea and respiratory depression (0.5%), and excessive salivation (0.3%). There were no adverse outcomes attributable to ketamine. Nearly half (46%) the subjects had severe underlying illness (American Society of Anesthesiologists (ASA] class > or =3). All instances of laryngospasm occurred during EGD (9.5% incidence), and the only independent predictor of laryngospasm in this sample was decreasing age. The incidence of laryngospasm was 13.9% in preschool-aged (< or =6 years) children and was 3.6% in school-aged (>6 years) children (difference 10.3%, 95% confidence intervals 5.5-14.9%). No dose relationship was noted with laryngospasm, and the risk did not increase with underlying illness. CONCLUSION Pediatric gastroenterologists skilled in ketamine administration and basic airway management can effectively administer this drug to facilitate gastrointestinal procedures. Transient laryngospasm occurred in 9.5% of children receiving ketamine for EGD, and its incidence was greater in preschool than in school-aged children.

Can paramedics accurately identify patients who do not require emergency department care

Objective. To determine whether paramedics can identify patients contacting 9-1-1 who do not require emergency department (ED) care. Methods. The setting was an urban county with a two-tiered, dual response to 9-1-1 calls comprising eight local fire departments with advanced life support capabilities and a private advanced life support 9-1-1 agency with primary transport responsibilities (approximately 39,000 of the 78,000 total system patient transports in this county per year). The study population consisted of consecutive patients transported by a private transporting paramedic agency. After patient contact and stabilization, paramedics completed a survey detailing the necessity for transport to an ED for each patient. Prior to data analysis, it was determined that patients would be designated as requiring ED care if they 1) were admitted, 2) required surgical, surgical subspecialty, obstetric, or gynecologic consult, or 3) required advanced radiologic procedures (excluding plain films). Sensitivity, specificity, and predictive values for paramedic assessment of necessity for ED care were calculated with 95% confidence intervals (95% CIs). Results. Over the study period, 313 patients were enrolled. Paramedic assessment was 81% sensitive (72-88%, 95% CI) and 34% specific (28-41%, 95% CI) in predicting requirement for ED care. In 85 cases where paramedics felt ED transport was unnecessary, 27 (32%) met criteria for ED treatment, including 15 (18%) who were admitted and five (6%) who were admitted to an intensive care unit. Conclusion. In this urban system, paramedics cannot reliably predict which patients do and do not require ED care.

Ketamine sedation for pediatric critical care procedures

Objectives To describe our experience using ketamine sedation to facilitate pediatric critical care procedures, and to document the safety profile of ketamine in this setting. Design Retrospective consecutive case series. Setting Pediatric intensive care unit of a tertiary children’s hospital. Patients Children receiving ketamine for procedural sedation over a 5-year period. Interventions We reviewed patient records to determine indication, dosing, adverse events, inadequate sedation, and recovery time for each sedation. Outcome Measures Descriptive features of sedation including adverse events. Results During the study period, children in our pediatric intensive care unit received ketamine at total of 442 times to facilitate a wide variety of critical care procedures, most commonly central line placement, esophagogastroduodenoscopy, and wound debridement. Most study children had substantial underlying illness (ASA ≥ 3 in 88%; ASA ≥ 4 in 39%). Inadequate sedation was noted in only nine (2%) procedures. Adverse effects included transient laryngospasm (n = 9), transient partial airway obstruction (n = 5), apnea with bradycardia (n = 1), emesis during the procedure (n = 2), emesis during recovery (n = 9), mild recovery agitation (n = 10), moderate-to-severe recovery agitation (n = 1), and excessive salivation (n = 4). There were no adverse outcomes attributable to ketamine. Conclusion Pediatric intensivists skilled in ketamine administration can safely and effectively administer this drug to facilitate critical care procedures. Despite the ill nature of our patient sample, adverse effects were uncommon.

Reliability of Infrared Tympanic Thermometry in the Detection of Rectal Fever in Children

STUDY OBJECTIVE Recently published clinical guidelines for the management of febrile children are based on studies that used rectal temperature data to stratify the risk of bacteremia and septic complications. Appropriate management decisions rely on accurate detection and categorization of fever. Accordingly, this study compared the newer infrared tympanic thermometry (ITT) to rectal thermometry in this regard. DESIGN Prospective observational study. SETTING Urban teaching hospital ED with annual census of 60,000. PARTICIPANTS Consecutive children 6 months to 6 years old who had rectal temperatures measured. INTERVENTIONS Triage nurses recorded rectal temperatures and bilateral ITT temperatures. Temperatures were correlated by Pearson correlation coefficients and compared using paired t tests with significance set at P < .01. Children were categorized by degree of fever using rectal temperature (afebrile, less than 100.4 degrees F; low fever, 100.4 to 102.9 degrees F; and high fever, more than 102.9 degrees F), and the accuracy of ITT in detecting fever and high fever was determined. RESULTS Three hundred seventy patients were enrolled in the study. The mean age was 18.4 +/- 11.3 months; boys comprised 56% of patients. The mean temperatures were rectal, 101.0 +/- 2.0 degrees F; right tympanic membrane, 100.4 +/- 1.9 degrees F; and left tympanic membrane, 100.3 +/- 1.9 degrees F. The tympanic membrane temperatures were significantly lower than rectal readings (P << .001 for both right and left versus rectal). Rectal temperatures showed good correlation with both right and left tympanic membrane temperatures (r = .83 and .85, respectively). ITT was 76% sensitive and 92% specific in detecting fever of 100.4 degrees F or more (positive predictive value, 0.92; negative predictive value, 0.76). In the detection of high fever, ITT was only 57% sensitive but 98% specific (positive predictive value, 0.90; negative predictive value, 0.90). Rectal and TM temperatures differed by at least 0.5 degree F in 70% of the patients, 1.0 degree F in 41%, 2.0 degrees F in 12%, and 3.0 degrees F in 3%. CONCLUSION Despite the statistical correlation between ITT and rectal temperatures, the modalities may yield significantly different temperatures. The poor sensitivity of ITT in detecting fever and high fever may result in clinically important miscategorizations of individual patients. Current clinical management that is based on the presence and height of fever may be adversely affected if ITT is used.

Validation of Diphenhydramine as a Dermal Local Anesthetic

STUDY OBJECTIVE Although diphenhydramine has been recommended as an alternate local anesthetic for patients claiming allergy to lidocaine, no prior placebo-controlled evaluations of diphenhydramine for dermal anesthesia have been performed. We sought to determine the relative efficacy of diphenhydramine compared to saline placebo and lidocaine. DESIGN Prospective, randomized, double-blind, placebo-controlled clinical trial. SETTING AND PARTICIPANTS Twenty-four healthy adult volunteers. INTERVENTIONS Subjects received intradermal 0.5-mL injections of diphenhydramine 1%, diphenhydramine 2%, lidocaine 1%, and normal saline placebo in a randomized, double-blind fashion. Extent of anesthesia (in mm2) was assessed at one, two, five, ten, 20, and 30 minutes. Pain of initial infiltration was assessed with a visual analog scale. MEASUREMENTS AND MAIN RESULTS Diphenhydramine 1% produced greater anesthesia than placebo (P < .001) and equivalent anesthesia to lidocaine 1% (P = .889). (Our sample size had 90% power to detect a difference of 30% from the peak anesthesia observed.) Diphenhydramine 2% was less effective than diphenhydramine 1%; however, this difference was not statistically significant (P = .295). Infiltration of either concentration of diphenhydramine was significantly more painful than either lidocaine or saline (P < or = .001) for all comparisons). No clinically important complications were noted. CONCLUSION In this study of 24 adult volunteers, diphenhydramine 1% was as effective as lidocaine 1% for achieving dermal local anesthesia, although injection was more painful. Although no clinically important complications were noted in our study, the safety of diphenhydramine remains to be established, especially in areas with poor collateral perfusion (eg, digits, pinna, and nose).

Do published guidelines predict pneumonia in children presenting to an urban ED

Objectives In 1997, a Canadian task force published evidence-based guidelines for diagnosing pediatric pneumonia, concluding that the absence of each of four signs (ie, respiratory distress, tachypnea, crackles, and decreased breath sounds) accurately excludes pneumonia. The study was performed to evaluate the accuracy of these guidelines in predicting pneumonia in young children. Methods This was an observational study conducted over a 4-month period at an urban emergency department with 80,000 annual visits, approximately 20% of which were children ≤5 years old. Consecutive children ≤5 years old who underwent chest radiography were enrolled. Prior to ordering radiographs, treating physicians were required to enter specific patient signs and symptoms into a computerized database. World Health Organization criteria were used to define tachypnea. Sensitivity, specificity, and predictive values of the task force guidelines in predicting pneumonia were calculated. Results Three hundred twenty-nine children, including 67 (20%) with pneumonia, were enrolled. Guidelines were 45% sensitive (95% confidence interval (CI) = 33–58) and 66% specific (95% CI = 60–72) for diagnosing pneumonia. Positive and negative predictive values were 25% (95% CI = 18–34) and 82% (95% CI = 77–87), respectively. Conclusion Previously published evidence-based guidelines for excluding pediatric pneumonia were found unreliable in this study.

Delayed appendicitis from an ingested foreign body

An unusual case of acute appendicitis induced by a metal drill bit that was ingested by a 27-year-old man 3 years before presentation is reported. This foreign body lodged in the patients appendix and developed a fecalith coating. When this fecalith coating enlarged enough to obstruct the appendiceal lumen, the patient presented with classic acute appendicitis. Foreign body-induced appendicitis is reviewed.