Stephen Lawless

Crying wolf : false alarms in a pediatric intensive care unit

ObjectiveTo determine the predictive value of patient monitoring alarms as a warning system in a pediatric intensive care unit (ICU). DesignProspective, observational study. SettingPediatric ICU of a university affiliated childrens hospital. InterventionsDuring a 7-day period, ICU staff were asked to record the type and number of alarm soundings. Alarms were recorded as false, significant (resulted in change in therapy), or induced (by staff manipulations; not significant). Measurements and Main ResultsSixty-six percent of nursing shifts (928 patient hours of care) responded. There were 2,176 alarms soundings: 1,481 (68%) false, 119 (5.5%) significant, and 576 (26.5%) induced. Alarm origins were: 44% pulse oximeter, 1% end-tidal PcO2, 31% ventilator, and 24% electrocardiograph (EKG). The positive predictive value of alarms were: 7% pulse oximeter, 16% end-tidal PcO2, 3% ventilator, and 5% EKG. The negative predictive value of all alarms were >97%. More alarms sounded during the 7:00 am to 3:00 pm shift than during the 3:00 pm to 11:00 pm or 11:00 pm to 7:00 am shifts (167 ± 19 vs. 64 ± 39 vs. 75 ± 43, p< .05, respectively). When corrected for number of patients/shift, the occurrence of soundings differed only between day and night (11.4 ± 1.5/patient/shift vs. 6.1 ± 1.0, p < .05). ConclusionsOver 94% of alarm soundings in a pediatric ICU may not be clinically important. Present monitoring systems are poor predictors of untoward events. (Crit Care Med 1994; 22:981–985)

Noninvasive ventilation via bilevel positive airway pressure support in pediatric practice.

OBJECTIVE To evaluate the efficacy of bilevel positive airway pressure support in critically ill children with underlying medical conditions. DESIGN Prospective, clinical study. SETTING Pediatric intensive care unit (ICU). PATIENTS Thirty-four patients (6 mos to 20 yrs, mean 11.06 +/- 0.9 yrs) with impending respiratory failure were enrolled in the study. All patients required airway or oxygenation/ventilation support (awake or asleep) and required admission to our pediatric ICU. Each patient served as his or her own control. Exclusion criteria were absent cough or gag reflex, multiple organ system failure, age of <6 mos, vocal cord paralysis, and noncooperation with nasal mask. INTERVENTIONS Bilevel positive airway pressure support ventilation. MEASUREMENTS AND MAIN RESULTS Thirty-four patients with 35 episodes of respiratory insufficiency requiring airway support or oxygenation/ventilatory support were treated with bilevel positive airway pressure support ventilation. Dyspnea score decreased at least two deviations in all patients; dyspnea score decreased five deviations in 67% of patients. Resting heart rate decreased from 126 +/- 3.2 to 102 +/- 3.2 beats/min (p < .001), respiratory rate decreased from 39 +/- 3 to 25 +/- 1 breaths/min (p < .004), bicarbonate concentrations decreased from 30.0 +/- 1.0 to 24.0 +/- 0.7 mmol/L (p < .01), and room air saturation increased from 85 +/- 2% to 97 +/- 1%. Bilevel positive airway pressure support ventilation failure was characterized by an inability to stabilize progression of respiratory failure and the subsequent placement of an artificial airway. Three patients required placement of an artificial airway. CONCLUSIONS A decrease in respiratory rate, heart rate, and dyspnea score and an improvement in oxygenation were noted in >90% of patients studied, resulting in only an 8% frequency of intubation. The efficacy of bilevel positive airway pressure support ventilation in selected groups of patients indicates the need to include this form of noninvasive pressure support ventilation in the care offered by pediatric ICUs.

Pharmacokinetics and pharmacodynamics of milrinone lactate in pediatric patients with septic shock

OBJECTIVES The objectives of this study were to determine the pharmacokinetics of milrinone lactate in pediatric patients with septic shock and to determine whether a relationship exists between steady-state plasma milrinone concentrations and changes in hemodynamic variables. STUDY DESIGN This was a randomized, double-blind, placebo-controlled, interventional study. In study phase 1 patients were randomized and underwent loading and infusion with milrinone lactate (50 microg/kg, then 0.5 microg/kg/min), and invasive hemodynamic values were determined. Steady-state was determined by obtaining plasma samples at 30, 15, and 0 minutes before the end of the milrinone infusion. Study phase 2 started when milrinone was discontinued by the patient care team. Steady-state was reaffirmed and plasma samples were obtained at 0.5, 1, 2, 4, 6, and 8 hours after the end of the infusion. RESULTS The average plasma concentration at steady-state (Css avg) and total body clearance for phase 1 were 81.3+/-38.6 ng/ml (mean +/- SD) and 0.0106+/-0.0053 L/kg/min, respectively (n = 9). All but two patients underwent reloading with milrinone. In phase 2 Css avg and total body clearance were 65.8+/-42.1 ng/ml and 0.0110+/-0.0096 L/kg/min, respectively (n = 11). The average time of infusion was 51+/-21 hours. Eight patients were evaluated for phase 2 elimination. The mean elimination rate constant was 0.0091+/-0.0061 min(-1) (n = 8). The median half-life was 1.47 hours (range, 0.62 to 10.85 hours). All patients had creatinine clearances greater than 61 ml/min/1.73 m2. The volume of distribution at steady-state was 1.47+/-1.03 L/kg. No correlation existed between age and the elimination rate constant or the volume of distribution at steady-state. All patients achieved at least a 20% change in cardiac index and systemic vascular resistance index while maintaining a Css avg of 35 to 160 ng/ml. No adverse effects were noted. All patients achieved primary hemodynamic end points (cardiac index and systemic vascular resistance index) during the milrinone infusion. CONCLUSIONS Loading doses of 75 microg/kg milrinone lactate and starting infusion rates of 0.75 to 1.0 microg/kg/min for patients with normal renal function should be used; the infusion rate should then be titrated to effect. We recommend that for every increase of 0.25 microg/kg/min, a 25 microg/kg bolus dose be given. Because the median half-life is 1.47 hours, immediate hemodynamic effects may not be seen unless appropriate loading doses and infusion adjustments are made.

Pancreatitis in patients with organic acidemias

STUDY OBJECTIVE The discovery of pancreatitis in two children with methylmalonic acidemia led us to review the experience with pancreatitis in a large number of patients with organic acidemias to determine whether pancreatitis is an important complication of these disorders. DESIGN Case series. SETTING Pediatric metabolism services at five tertiary care centers. PATIENTS Records of all patients with organic acidemias followed at the five institutions during the past 10 years were reviewed. Pancreatitis was recognized by symptoms and laboratory findings and confirmed by imaging studies, surgery, or autopsy. At three institutions all cases of pancreatitis in children younger than 10 years were reviewed. MEASUREMENTS AND RESULTS Nine children with pancreatitis (seven with acute and two with chronic cases) were identified among 108 children with branched-chain organic acidemias. They ranged in age from 13 months to 9 years. Five had methylmalonic acidemia, three had isovaleric acidemia, and one had maple syrup urine disease. There were three deaths; acute hemorrhagic pancreatitis occurred in two children, and chronic pancreatitis was found at autopsy in a third. All three patients with isovaleric acidemia and pancreatitis were identified after the occurrence of pancreatitis. The survey of pancreatitis at three institutions found 57 other patients (none with an inborn error) in addition to three patients with inborn errors included in this study. CONCLUSIONS Acute or chronic pancreatitis may complicate branched-chain organic acidemias and must be considered in the assessment of patients with these disorders who have acute clinical deterioration and vomiting, abdominal pain, encephalopathy or shock, or milder symptoms. Conversely, an inborn error of organic acid metabolism should be considered in children with pancreatitis of unknown origin.

Increased incidence of head and neck abscesses in children

Objective To describe increasing incidence and changing microbiology of head and neck abscesses in children admitted to the hospital during the first quarters of 2000 through 2003. Study Design and Setting Retrospective data warehouse review identified 89 children less than 19 years of age admitted to a tertiary care pediatric hospital during the first quarters of 2000 through 2003 for suspicion of head and neck abscess involving the neck, face, and peritonsillar, retropharyngeal, and parapharyngeal spaces; and for orbital and intracranial complications of acute sinusitis. Outcome Measures Outcome measures included the incidence of infection admissions and description of infection location and microbiology, calculated by χ2 technique. Results The incidence of infections increased in 2003. The greatest increase was in neck abscesses and complications of acute sinusitis. Conclusions The increase in group A strep infections may be related to its biologic properties. Significance Group A strep remains a significant cause of head and neck infections in children.

A Pilot Survey of Vocal Health in Young Singers

The objective of this study was to determine the incidence of vocal problems in young choir singers and to correlate vocal problems with demographic and behavioral information. A questionnaire addressing vocal habits and hygiene was offered to 571 young choir singers, up to 25 years of age, who sing at least weekly; 129 (22.6%) responded. More than one-half of the respondents had experienced vocal difficulty, particularly older adolescents. Detrimental behaviors and circumstances surveyed were not reflective of the incidence of vocal difficulty, except for morning hoarseness, chronic fatigue, insomnia, and female gender after puberty. Voice care professionals should be aware that self-reported voice difficulties are common among young choral singers, especially postpubescent girls, and children with symptoms consistent with reflux (morning hoarseness) and emotional stress (insomnia). Laryngologists should communicate with choral conductors and singing teachers to enhance early identification and treatment of children with voice complaints, and to develop choral educational strategies that help decrease their incidence.

Amrinone in neonates and infants after cardiac surgery

Eighteen critically ill postoperative patients less than 1 yr of age were studied to determine the pharmacokinetics and adverse effects of amrinone. All patients had undergone cardiopulmonary bypass for repair of congenital heart lesions. Plasma samples were obtained every 12 h while patients were receiving amrinone to determine when steady state was achieved; samples were also obtained within 24 h after amrinone had been discontinued. Elimination half-life (T1/2), clearance, and volume of distribution were calculated from plasma amrinone concentrations, and the incidence of platelet transfusion was monitored. T1/2(22.2 vs. 6.8 h) and clearance (1.1 vs. 2.6 ml/min.kg), but not the volume of distribution (1.8 vs. 1.6 L/kg), differed significantly in patients less than 4 wk of age in comparison to patients greater than 4 wk of age. A negative correlation between T1/2 and age (r = -.79) was observed. Platelets were administered no more frequently in study patients than in a similar group that did not receive amrinone. To achieve the plasma concentration of amrinone that is therapeutic in adults, current dosage recommendations are inadequate in neonates and infants. Infants should receive an initial iv amrinone bolus of 3.0 to 4.5 mg/kg in divided doses followed by a continuous infusion of 10 micrograms/kg.min, while neonates should receive a similar bolus followed by a continuous infusion of 3 to 5 micrograms/kg.min.

Postoperative bilevel positive airway pressure ventilation after tonsillectomy and adenoidectomy in children — a preliminary report☆

Obstructive sleep apnea (OSA) in children, characterized by hypoventilation secondary to upper airway obstruction, often results from tonsil and adenoid hypertrophy. Adenotonsillectomy is the standard therapy in this patient population. The immediate postoperative period is complicated occasionally by respiratory difficulties that may require intubation and mechanical ventilation. Recently, physicians have provided temporary airway support using continuous and bilevel positive airway pressure (BiPAP) devices. Reported complications of positive airway pressure devices include local abrasions to the nose and mouth; dryness of the nose, eyes, and mouth; sneezing; nasal drip, bleeds, and congestion; sinusitis; increased intraocular pressure; non-compliance; and pneumocephalus. Subcutaneous emphysema following facial trauma, dental extractions, adenotonsillectomy, and sinus surgery has been reported. There is also a hypothetically increased risk of subcutaneous emphysema following the use of positive airway pressure ventilation in the tonsillectomy patient. Between January 1997 and July 1998, 1321 patients underwent tonsillectomy and/or adenoidectomy at our institution. In reviewing the records of all pediatric intensive care unit admissions during that time period, we identified nine patients, of the 1321, who required BiPAP postoperatively. Of these, four children were obese, four had preexisting neurological disorders, and one underwent endoscopic sinus surgery and adenoidectomy. Three children were asthmatic, and three were less than 3 years of age. Two obese children were discharged with home BiPAP, one of whom had been on BiPAP prior to surgery. All patients tolerated BiPAP without complications. This preliminary report suggests that BiPAP is a safe and effective method of respiratory assistance in the adenotonsillectomy patient with preexisting conditions who is predisposed to postoperative airway obstruction. Furthermore, with BiPAP, the risks of intubation and ventilator dependence are avoided.

New pigtail catheter for pleural drainage in pediatric patients.

The conventional method of pleural drainage is tube thoracotomy, accomplished by chest wall dissection and blunt puncture. While this method is successful, it is relatively traumatic. We have designed a pigtail catheter which may be inserted into the pleural space by a modified Seldinger technique. This 8.5-Fr polyurethane catheter has six side ports inside its circular distal end. An airtight plastic bag is attached to the insertion needle to confirm pleural placement. Nineteen catheters were inserted in 16 neonates and small children with either pneumothorax or pneumomediastinum. No complications were noted. All but one pneumothorax was successfully evacuated; however, the pneumomediastinum reaccumulated. Insertion proved to be safe, simple, and atraumatic. This pigtail pleural drainage catheter provides an alternative to standard tube thoracotomy.

Quarterly Visits with Glycated Hemoglobin Monitoring: The Sweet Spot for Glycemic Control in Youth with Type 1 Diabetes

OBJECTIVE To evaluate the association between the frequency of visits and glycated hemoglobin (GHb) measurements on glycemic control in youth with type 1 diabetes. RESEARCH DESIGN AND METHODS A retrospective longitudinal cohort study of 1,449 youth with type 1 diabetes (mean age 11.4 years, 50% female, 74% Caucasian, 24% with Medicaid) followed at five pediatric endocrinology clinics from the years 2008–2011 was conducted. By hierarchical cluster analysis, three homogeneous groups of patients were generated: those with a relative increase in GHb (worsened [n = 237]), no change in GHb (stable [n = 842]), and a decrease in GHb (improved [n = 370]) over the study period. The number of visits and GHb measurements per year were compared among the three groups by multinomial logistic regression analysis using one visit or GHb test per year as a reference and controlling for patient demographic and baseline characteristics. RESULTS Patients with quarterly visits were least likely to have worsened glycemic control (odds ratio 0.33, P < 0.05) and were most likely to have improved glycemic control (3.48, P < 0.01). Patients with four GHb tests a year (0.53, P < 0.05) were least likely to have worsened glycemic control. CONCLUSIONS Quarterly visits and GHb testing are associated with glycemic control in youth with type 1 diabetes.