P.S.K. Mak

Mid-arm circumference can be used to estimate children's weights.

INTRODUCTION Accurate measurement of childrens weight is rarely possible in paediatric resuscitation, and rapid estimates are made to ensure appropriate drug and fluid doses and equipment selection. Weight is commonly estimated from formulae based on childrens age, or from their height using the Broselow tape. Foot-length and mid-arm circumference have also been suggested as the basis of weight-estimation formulae. OBJECTIVES To determine which of age, height, foot-length or mid-arm circumference had the strongest relationship with weight in healthy children, to derive a simple weight-estimation formula from the strongest correlate, and to compare its performance with existing weight-estimation tools. METHODS This was a population-based prospective observational study of Hong Kong Chinese children aged 1-11 years old last birthday. Weight was measured to the nearest 0.2 kg; height, foot-length and mid-arm circumference to the nearest 0.1 cm. Multiple regression analysis was used to determine the strongest independent relationships with weight, and linear regression analysis derived a weight-estimation formula. Accuracy and precision of this formula were compared with standard age-based and height-based weight-estimation methods. RESULTS Mid-arm circumference had the strongest relationship with weight, and this relationship grew stronger with age. The formula, weight [kg]=(mid-arm circumference [cm]-10) x 3, was at least as accurate and precise as the Broselow method and outperformed the age-based rule in school-age children, but was inadequate in pre-school children. CONCLUSION This weight-estimation formula based on mid-arm circumference is reliable for use in school-age children, and an arm-tape could be considered as an alternative to the Broselow tape in this population.

The normal ranges of cardiovascular parameters in children measured using the Ultrasonic Cardiac Output Monitor.

Objective:The Ultrasonic Cardiac Output Monitor is a noninvasive method of hemodynamic assessment and monitoring in critically ill patients. There are no published reference ranges for normal values in children for this device. This study aimed to establish normal ranges for cardiovascular indices measured using Ultrasonic Cardiac Output Monitor in children aged 0–12 yrs old and to assess interobserver reliability. Design:This was a population-based cross-sectional observational study. Setting:Schools and kindergartens in Hong Kong. Subjects:Chinese children aged up to 12 yrs old. Interventions:Two operators performed Ultrasonic Cardiac Output Monitor scans on each child together with standard oscillometric measurement of blood pressure and heart rate. Software intrinsic to the Ultrasonic Cardiac Output Monitor device produces values for stroke volume, cardiac output, and systemic vascular resistance. For each parameter, normal ranges were defined as lying between the 2.5th and 97.5th percentiles. Interobserver reliability was assessed with Bland-Altman plots, coefficients of variation, and intraclass correlation. Measurements and Main Results:A total of 1,197 Chinese children (55% boys) were scanned. Normal ranges of values for cardiac output, stroke volume, and systemic vascular resistance indices are presented. Interobserver reliability for Ultrasonic Cardiac Output Monitor was superior to that for standard blood pressure and heart rate measurement. Conclusions:This large study presents normal values for cardiovascular indices in children using the Ultrasonic Cardiac Output Monitor with good interobserver reliability.

Predictors of important neurological causes of dizziness among patients presenting to the emergency department.

Objectives Dizziness is a common presenting complaint in the emergency department (ED). This prospective study describes the incidence, causes and outcome of ED patients presenting with dizziness and tries to identify predictors of central neurological causes of dizziness. Methods Single-centre prospective observational study in a university teaching hospital ED in Hong Kong. All ED patients (≥18 years old) presenting with dizziness were recruited for 1 month. Symptoms, previous health, physical findings, diagnosis and disposition were recorded. The outcome at 3 months was evaluated using hospital records and telephone interviews. Follow-up was also performed at 55 months using computerised hospital records to identify patients with subsequent stroke and those who had died. Results 413 adults (65% female, mean 57 years) were recruited. The incidence of dizziness was 3.6% (413/11 319). Nausea and/or vomiting (46%) and headache (20%) were the commonest associated findings. Hypertension (33%) was the commonest previous illness. Central neurological causes of dizziness were found in 6% (23/413) of patients. Age ≥65 years (OR=6.13, 95% CI 1.97 to 19.09), ataxia symptoms (OR=11.39, 95% CI 2.404 to 53.95), focal neurological symptoms (OR=11.78, 95% CI 1.61 to 86.29), and history of previous stroke (OR=3.89, 95% CI 1.12 to 13.46) and diabetes mellitus (OR=3.57, 95% CI 1.04 to 12.28) predicted central causes of dizziness. Conclusions Most dizzy patients had benign causes. Several clinical factors favoured a diagnosis of central neurological causes of dizziness.

Age-based formulae to estimate children's weight in the emergency department

Objective To develop an age-based weight estimation rule in a Chinese population and to compare its performance with existing formulae. Design Population-based observational study. Setting Schools and kindergartens in Hong Kong. Subjects Healthy Chinese children aged 1–10 years old on their last birthday. Interventions Weight was measured to the nearest 0.2 kg. Main outcome measures Linear regression was used to derive a simple formula relating weight to the childs age on his or her last birthday. The accuracy and precision of different age-based weight formulae was compared using coefficient of variation, Bland Altman plots, and by determining the proportion of children with estimates >30% outside the actual weight. Results The Chinese Age Weight Rule is a simple linear formula that is more accurate than and at least as precise as any other age-based weight estimation rule: weight in kg=(3×age last birthday)+5. It is accurate and precise in children <7 years old, but all age-based weight estimates are imprecise in older children. Conclusions The Chinese Age Weight Rule should be used in a Chinese population in preference to any other age-based weight estimation rule. Caution should be taken when using it in older children in whom other weight-estimation tools may be more appropriate.

Adult epiglottitis: 6 years experience in a university teaching hospital in Hong Kong

Adult epiglottitis is a relatively rare but potentially lethal disease. It seems to be increasing in incidence in other countries. The objective of this study was to examine the common presentations and clinical course of adult epiglottitis in Hong Kong. Retrospective review of 80 consecutive cases of adult epiglottitis admitted between 2000 and 2005. A rising trend in the incidence of adult epiglottitis was observed. The mean age (SD) was 49 years (15.7) and the male-to-female ratio was 2.5 : 1. Disease presentation was nonspecific and sore throat was the most common symptom. All patients were admitted to hospital; 47 (59%) patients were admitted to the intensive care unit (ICU) and 31 (39%) had provision of an artificial airway. Mean (SD) length of stay in ICU and hospital was 1.9 (2.2) and 6.3 (2.9) days, respectively. Six patients (7.5%) were complicated by epiglottic abscess formation. No deaths occurred in this series. Patients who required airway intervention had a higher ICU admission rate and a higher bacterial identification rate. Flexible laryngoscopy was more sensitive than lateral neck radiography in diagnosing epiglottitis (100 vs. 81.4%). The laryngoscopic finding of a narrowed airway was strongly related to the requirement for airway intervention (odds ratio=23.7, 95% confidence interval=4.2–132.6, P<0.001). A high index of suspicion is required for making the diagnosis of adult epiglottitis. Proper airway assessment and close monitoring are of the utmost importance in patient management. Flexible laryngoscopy is the key investigation of choice in the emergency department.

Validation of a Modified Early Warning Score (MEWS) in emergency department observation ward patients

Objective The Modified Early Warning Score (MEWS) is a simple physiological scoring system, which can easily be applied at the bedside. The ability of MEWS to identify patients at risk of deterioration in a busy ward was investigated. Method In a prospective cohort study, we applied MEWS to patients admitted to the 16-bed emergency department observation ward (EDOW) of a tertiary teaching hospital. Results Data on 427 consecutive EDOW admissions were collected from 7 June to 4 July 2004. Main outcome measures were death, intensive care unit (ICU) admission and inpatient hospital admission. Scores of > 4 were associated with increased risk of death (OR 54.4, 95% CI = 4.7–633.7), ICU admission (OR 12.7, 95% CI = 1.1–147.3) and hospital admission (OR 9.5, 95% CI = 3.3–27.9). Conclusion MEWS is suitable for bedside application in an EDOW setting and may help identify patients at risk of deterioration who require increased levels of care as hospital inpatients and in ICU. Where experienced staff is not available to closely monitor patients in an EDOW, the use of the MEWS system may aid close monitoring and identification of high-risk patients.

Disease severity prediction for nursing home-acquired pneumonia in the emergency department

Background Prediction rules exist for the assessment of community-acquired pneumonia but their use in nursing home-acquired pneumonia (NHAP) remains undefined. The objectives of this study were to compare the prognostic ability for severe NHAP of five prediction rules (PSI, CURB-65, M-ATS, R-ATS, España rule), and to evaluate their usefulness to identify patients with less severe disease in the emergency department for outpatient care. Methods A prospective observational study of consecutive NHAP patients was conducted at a university teaching hospital emergency department in Hong Kong between January 2004 and June 2005. The primary outcome was severe pneumonia (defined as combined 30-day mortality and/or intensive care unit (ICU) admission). Results 767 consecutive NHAP patients were included. Mean (SD) age was 83.4 (9.0) years; 350 (45.6%) were male and 644 (84.0%) had coexisting illness. 95 patients died within 30 days (12.4%), five patients were admitted to the ICU (0.7%) and 98 patients had severe pneumonia (12.8%). Sensitivity and specificity of each decision rule ranged from 37.8% to 95.9% and 15.1% to 87.6% respectively. The overall predictive performance of each rule was between 0.627 and 0.712. The negative likelihood ratios of PSI (0.27) and CURB-65 (0.23) were lower than M-ATS (0.71), R-ATS (0.45) and España (0.39). After excluding 204 patients with either poor functional status or those >90 years of age, sensitivities of M-ATS (96.0%) and R-ATS (100%) improved greatly with negative likelihood ratios of <0.1. Conclusion PSI and CURB-65 are useful for identification of patients with less severe NHAP.

Nurse-initiated defibrillation: are nurses confident enough?

Objectives To determine the capability of nurses to identify ventricular fibrillation (VF) and ventricular tachycardia (VT) rhythms on an ECG and carry out subsequent defibrillation on their own as soon as they identify and confirm cardiac arrest. Methods This was a prospective cohort study to determine the capability of emergency department (ED) nurses to recognise VF or pulseless VT correctly and their willingness to perform defibrillation immediately in an ED of a teaching hospital in Hong Kong. A questionnaire was completed before and after a teaching session focusing on the identification of rhythms in cardiac arrest and defibrillation skills. Correct answers for both ECG interpretation and defibrillation decisions scored one point for each question. The differences in mean scores between the pre-teaching and post-teaching questionnaires of all nurses were calculated. Results 51 pre-teaching and 43 post-teaching questionnaires were collected. There were no statistically significant changes in ECG scores after teaching. For defibrillation scores, there was an overall improvement in the defibrillation decision (absolute mean difference 0.42, p=0.014). Performance was also improved by the teaching (absolute mean difference 0.465, p=0.046), reflected by the combination of both scores. Two-thirds (67%) of nurses became more confident in managing patients with shockable rhythms. Conclusion Nurses improve in defibrillation decision-making skills and confidence after appropriate brief, focused in-house training.

Features discriminating SARS from other severe viral respiratory tract infections

This study investigated the discriminatory features of severe acute respiratory syndrome (SARS) and severe non-SARS community-acquired viral respiratory infection (requiring hospitalization) in an emergency department in Hong Kong. In a case-control study, clinical, laboratory and radiological data from 322 patients with laboratory-confirmed SARS from the 2003 SARS outbreak were compared with the data of 253 non-SARS adult patients with confirmed viral respiratory tract infection from 2004 in order to identify discriminatory features. Among the non-SARS patients, 235 (93%) were diagnosed as having influenza infections (primarily H3N2 subtype) and 77 (30%) had radiological evidence of pneumonia. In the early phase of the illness and after adjusting for baseline characteristics, SARS patients were less likely to have lower respiratory symptoms (e.g. sputum production, shortness of breath, chest pain) and more likely to have myalgia (p < 0.001). SARS patients had lower mean leukocyte and neutrophil counts (p < 0.0001) and more commonly had “ground-glass” radiological changes with no pleural effusion. Despite having a younger average age, SARS patients had a more aggressive respiratory course requiring admission to the ICU and a higher mortality rate. The area under the receiver operator characteristic curve for predicting SARS when all variables were considered was 0.983. Using a cutoff score of >99, the sensitivity was 89.1% (95%CI 82.0–94.0) and the specificity was 98.0% (95%CI 95.4–99.3). The area under the receiver operator characteristic curve for predicting SARS when all variables except radiological change were considered was 0.933. Using a cutoff score of >8, the sensitivity was 80.7% (95%CI 72.4–87.3) and the specificity was 94.5% (95%CI 90.9–96.9). Certain clinical manifestations and laboratory changes may help to distinguish SARS from other influenza-like illnesses. Scoring systems may help identify patients who should receive more specific tests for influenza or SARS.

Treatment and outcome of acute cardiogenic pulmonary oedema presenting to an emergency department in Hong Kong: retrospective cohort study

Objectives To explore the epidemiology, treatment and outcome of acute cardiogenic pulmonary oedema (ACPO) in a Hong Kong emergency department (ED). Methods This was a retrospective cohort study in a university hospital ED. Cases were identified from ED records and resuscitation room logbooks. The study extended from 1 September 2004 to 30 April 2005. Parametric tests and logistic regression were used to identify predictors of survival. Results A total of 140 patients were identified, with a mean age of 75 years and male:female ratio of 1:1.4. Mean values (range) on presentation were as follows: pulse rate 103 beats/minute (36–108); blood pressure (BP) 169/88 mmHg (77-274/20-162) and respiratory rate 31 breaths/minute (12–88). Past medical history included previous ACPO (12.1%), diabetes (45.7%), chronic obstructive pulmonary disease (9.3%), ischaemic heart disease (45.0%), hypertension (72.1%) and congestive heart failure (40.7%). On admission, 47.1% had pH<7.35 and 40.7% had PaCO2>5.5kPa. ED treatments included: sublingual nitrates (n=2), intravenous (IV) nitrates (n=89, median 10 mg/hr), IV frusemide (n=85, median 40 mg), IV morphine (n=25, median 3 mg). There were 21 patients on non-invasive ventilation; 27 intubations and 41 patients were admitted to the intensive care unit. Survival to discharge was 95.7%; and median length of hospital stay was 8 days. The 90-day all-cause hospital readmission rate was 30.0%. The 30-day mortality was 12.9% (n=18) and 90-day mortality was 29.3% (n=41). Logistic regression showed that past history of hypertension (p=0.0061), higher systolic BP on ED discharge (p=0.0102) and lower creatinine following treatment (p=0.035) were predictors of improved survival at 90 days. Conclusion ACPO commonly presents to the ED in Hong Kong and has a high 90-day mortality. Previous hypertension, higher systolic blood pressure on leaving the ED and lower creatinine following treatment predict improved survival at 90 days.