EMLA versus TAC for topical anesthesia of extremity wounds in children.

STUDY OBJECTIVE: To compare the anesthetic efficacy of EMLA (eutectic mixture of local anesthetics) cream with that of TAC (tetracaine, adrenaline, and cocaine) solution for suturing uncomplicated extremity wounds. METHODS: We conducted a prospective, single-blind, randomized trial in a convenience sample of 32 children, ages 5 to 18 years, who required repair of an extremity laceration. Eligible wounds were less than 5 cm long and less than 12 hours old. Lacerations involving digits, deep tissues, or musculature were excluded. Patients receiving medications that predisposed them to methemoglobinemia were also excluded. Lacerations were treated with TAC .1 mL/kg (maximum, 3.0 mL) or EMLA .15 g/kg (maximum, 5.0 g). Anesthesia was assessed every 10 minutes. TAC and EMLA were allowed to remain on the wounds for a maximum of 30 and 60 minutes, respectively. Anesthesia was deemed successful if no supplemental lidocaine was required, as judged by a suturing caregiver who was blinded to the anesthetic used. RESULTS: The two groups were similar with regard to age, sex, wound length and depth, and wound age. EMLA-treated wounds were repaired without supplemental anesthesia more often than TAC-treated wounds: 13 of 16 (85%) versus 7 of 16 (45%, P= .03). More time was required for EMLA to cause anesthesia (55 versus 29 minutes, P<.01). Dehiscence occurred in one wound in each group; no wound infections were observed. CONCLUSION: EMLA appears to be superior to TAC for anesthesia of simple extremity lacerations in that those wounds treated with EMLA required supplemental anesthesia less often. EMLA required approximately 1 hour to cause optimal anesthesia in open wounds. Protocols should be developed to allow efficient use of EMLA for anesthesia of extremity lacerations in the ED.

End-tidal carbon dioxide changes during cardiopulmonary resuscitation after experimental asphyxial cardiac arrest.

A study was undertaken to determine the pattern of end-tidal carbon dioxide (ETCO2) changes during asphyxia-induced cardiac arrest in a pediatric canine model. Eleven intubated, anesthetized, paralyzed dogs (mean age, 4.1 mo; mean weight, 5.5 kg) were used. Asphyxia was induced by clamping the endotracheal tube (ETT) and discontinuing ventilation. Cardiac arrest ensued a few minutes later, after which closed-chest cardiopulmonary resuscitation (CPR) and ventilation were initiated. The ETCO2 level was recorded at baseline and every minute during CPR. Mean baseline ETCO2 was 31.9 mm Hg. The initial ETCO2 immediately after unclamping the ETT (mean, 35 mm Hg) was higher than subsequent values (mean, 12.4 mm Hg; P < .001). There was a sudden increase in ETCO2 to a mean of 27.0 mm Hg at or just before return of spontaneous circulation (ROSC) in all 11 cases (P < .01). During CPR, ETCO2 levels were initially high, decreased to low levels, and increased again at ROSC. This pattern, not previously described, is different from that observed in animal and adult cardiac arrest caused by ventricular fibrillation, during which ETCO2 decreases to almost zero after the onset of arrest, begins to increase after the onset of effective CPR, and increases to normal levels at ROSC. In this model of asphyxial arrest, continued cardiac output prior to arrest allows continued delivery Of CO2 to the lungs, resulting in higher alveolar CO2; this, in turn, is reflected as increased ETCO2 once ventilation is resumed during CPR. Further study is needed to determine whether the pattern Of ETCO2 changes can be used prospectively to define the etiology of cardiac arrest.

Effect of number of blood cultures and volume of blood on detection of bacteremia in children.

OBJECTIVE: To determine whether bacteremia can be detected more rapidly and completely by (1) obtaining two blood cultures instead of one and/or (2) collecting a larger volume of blood. STUDY DESIGN: Prospective comparison of different strategies in 300 patients undergoing blood culture for suspected bacteremia. Each patient had two samples of blood, A (2 ml) and B (9.5 ml), obtained sequentially from separate sites. The B sample was divided into three aliquots: B1 (2 ml), B2 (6 ml), and ISO (1.5 ml, quantitative culture). RESULTS: A pathogen was isolated from one or more blood cultures in 30 patients (10% of cases). When measured at 24 hours, the pathogen recovery rate for the B2 sample (72%) was higher than that for the individual small-volume samples (A = 37%, B1 = 33%; p < 0.01 for each comparison) and for the combination of the two small-volume samples (A + B1 = 47%; p = 0.04). At final (7-day) reading the pathogen recovery rate for the B2 sample (83%) was higher than that for B1 (60%; p = 0.02) and similar to the recovery rate observed with the combination of the two small-volume cultures (A + B1 = 73%; p = 0.55). CONCLUSIONS: Increasing the volume of blood inoculated into blood culture bottles improves the timely detection of bacteremia in pediatric patients and spares the patients the cost and pain of an additional venipuncture.

Pediatric emergency medicine fellow clinical work requirements.

A wide range of clinical requirements exists among PEM fellowship programs. Programs are equally split concerning the question of whether fellows should work with supervision or independently in the first year; a significant number of fellowship programs require continued supervision of fellows in subsequent years. Orientation for first year fellows and requirements for completion of PALS, advanced pediatric life support (APLS), ACLS, or ATLS courses prior to their first independent shift varied greatly. In particular, a minority of programs required ATLS completion even though a majority of overall fellowship programs operate in a hospital designated as a Level 1 Trauma Center. Programs in which first-year fellows worked independently had fewer attendings and were less likely to provide 24-hour coverage. Fellows appear to work a similar or less demanding schedule than PEM attendings in most fellowship programs, and most fellowship directors feel that their fellows should continue with their current schedule.

ATP-MgCl2 pre-treatment in an animal model of asphyxial arrest.

ATP-MgCl2 treatment has been found to be a promising intervention in many models of hypoxic/ischemic injury. In this study, the effect of pre-treatment with ATP-MgCl2 on the hemodynamic response to asphyxia in the rat was examined. Rats were anesthetized with halothane and N2O2. A tracheostomy and femoral artery and vein cutdowns were performed. Rats were infused intravenously with either ATP-MgCl2 (approximately 50 mumol/kg) or normal saline (control group) over 15 min. Animals were then asphyxiated for 8 min by occlusion of the ventilator tubing. Following the asphyxia, 1 min of cardiopulmonary resuscitation (CPR) was attempted. Heart rate and blood pressure were monitored continuously throughout the experiment. A total of 41 animals (21 ATP-MgCl2, 20 control) were studied. Analysis of variance (ANOVA) was used to test for differences between groups. The ATP-MgCl2 group had a lower heart rate (HR) and mean arterial pressure (MAP) during the infusion. During asphyxia the ATP-MgCl2 group had a lower MAP but higher HR when compared to the control group. No significant differences were observed in the rates of successful resuscitation between ATP-MgCl2-treated rats (10 of 21, 48%) and controls (12 of 20, 60%). Possible reasons for the apparent lack of benefit of ATP-MgCl2 therapy are discussed.

Use of portable ultrasound to assist urine collection by suprapubic aspiration.

STUDY OBJECTIVE: To determine whether portable ultrasound can improve the success rate of suprapubic aspiration (SPA). DESIGN: Patients were randomly assigned to either ultrasound or no ultrasound groups. In the ultrasound group, patients underwent SPA if ultrasound revealed urine in the bladder: if no urine was present, patients underwent catheterization instead of SPA. In the no-ultrasound group, SPA was attempted without ultrasound. All unsuccessful SPAs were followed by catheterization and measurement of urine volume. SETTING: Children's hospital-based pediatric emergency department. PARTICIPANTS: Children less than 2 years old who required SPA. INTERVENTIONS: Ultrasound versus no ultrasound. RESULTS: Thirty-five patients were randomized to the ultrasound group, and 31 were randomized to the no-ultrasound group. SPA was successful in 79% of attempts in the ultrasound group compared with 52% in the no-ultrasound group (P = .04). The sensitivity and specificity of ultrasound were 90% and 86%, respectively. CONCLUSION: Portable ultrasound can significantly improve the success rate of SPA and limit nonproductive attempts at SPA.

Long-term follow-up of children born to women immunized with tetanus toxoid during pregnancy.

Ten years after transplacental immunization with tetanus toxoid, the antibody responses of the immunized children to a booster immunization with 5 Lf tetanus toxoid did not differ from those of the control children. The tetanus toxoid-stimulated lymphocyte proliferative responses showed that there was no tolerance to tetanus toxoid induced by transplacental immunization, and the stimulation indices suggested that there may be some long-term memory for tetanus toxoid among the T lymphocytes in children who had been transplacentally immunized by maternal immunization with a standard dose of tetanus toxoid.

Utility of collecting blood cultures through newly inserted intravenous catheters.

We prospectively examined the utility of obtaining blood cultures through newly inserted intravenous catheters in 99 children who required both a blood culture and placement of an intravenous catheter. Two blood cultures were collected from each patient, one through a freshly inserted intravenous catheter and another through a butterfly needle at a separate venipuncture site. A standardized technique of skin preparation with povidone-iodine was used. The rate of contamination was 1.0% (95% confidence intervals, 0 to 3.0%) for each method. Ten patients had blood cultures yielding true pathogens; in five of these bacteremic children, only one of two sets of blood cultures was positive. We conclude that blood cultures can be collected through freshly placed intravenous catheters without increasing the risk of contamination. These results also raise the possibility that obtaining two blood cultures instead of a single culture may improve the detection of bacteremia in children.

Lack of effect of changing needles on contamination of blood cultures.

To determine whether changing needles during the collection of blood cultures reduces contamination, we randomly assigned 303 children undergoing blood cultures to 1 of 3 groups: no needle changes (blood instilled directly into culture media through the needle used for venipuncture); 1 needle change (before inoculation into the first of 2 culture bottles); and 2 needle changes (before inoculation into each of 2 culture bottles). Each patient's skin was cleansed with povidone-iodine for 60 seconds before venipuncture. We found similar rates of contamination among the 3 groups: no change, 2 of 92 (2.2%); 1 change, 0 of 106 (0.0%); 2 changes, 2 of 105 (1.9%). The combined contamination rate of all 3 groups (1.3%) was significantly lower than the prestudy rate of contamination (4.4%), based on 315 blood cultures (P = 0.04). These data suggest that careful skin preparation is a more important factor than changing needles in reducing contamination during blood culture collection.

Modification of otitis media in chinchillas rechallenged with nontypable Haemophilus influenzae and serological response to outer membrane antigens.

Otitis media was produced in chinchillas by right-sided intrabullar inoculation with nontypable Haemophilus influenzae, and susceptibility to reinfection was investigated. After resolution of initial right-sided infection, animals underwent ipsilateral or contralateral intrabullar rechallenge with the same strain. After ipsilateral rechallenge right ears were completely protected against reinfection; previously uninfected left ears were similarly protected on contralateral rechallenge. Previously infected ears remained fully susceptible to infection with a heterologous strain of nontypable H. influenzae. Using an enzyme-linked immunosorbent assay, we measured the serological response to outer membrane protein and lipopolysaccharide antigens during initial infection. A greater than or equal to 10-fold rise in titer of antibody to homologous outer membrane proteins was observed in all 11 animals tested. Most animals exhibited a minimal serological response to lipopolysaccharide. Thus experimental otitis media due to nontypable H. influenzae induces strain-specific protective immunity and a concomitant serological response to outer membrane proteins.

Do children with recurrent Haemophilus influenzae otitis media become infected with a new organism or reacquire the original strain?

Using the techniques of outer membrane protein gel analysis and biotyping, we characterized nontypable Haemophilus influenzae isolates from middle ear aspirates of 30 children with recurrent nontypable H, influenzae (NTHI) otitis media. Nine of the 13 children with early recurrence of NTHI otitis (less than 30-day intervals) had respective first and second isolates that were identical. In contrast, 14 of 18 children with late recurrences of NTHI otitis (greater than 30-day intervals) had respective first and second isolates that were different, whereas four children had late recurrences with organisms that appeared to be identical with their respective initial infecting strains. These results suggest that early recurrent NTHI otitis usually is a result of relapse with the initial infecting NTHI strain. In contrast, late recurrent disease is usually the result of infection with a new organism. However, the observation that four children had late recurrences with the original strains suggests that strain-specific protective immunity may not uniformly develop after recovery from NTHI otitis.