Linda Nadeau

C-reactive protein as biochemical indicator of bacterial infection in neonates

Serial quantitative measurements of C-reactive protein (CRP) were performed, using an automated enzyme immunoassay method, in 127 neonates (114 premature and 13 full-term) classified in three groups: neonates with a normal postnatal course (group 1, n = 69), neonates with clinical suspicion of bacterial infection but with negative cultures (group 2, n = 49), and neonates with proven bacterial infection (group 3, n = 9). A total of 545 serial serum CRP concentrations were determined. In group 1, CRP concentrations were below the detection limit of the method (10 mg/L) except in one neonate who suffered from neonatal anoxia but whose clinical course was uncomplicated (CRP: 31 mg/L within 24 h of life). Thirty-three neonates of group 2 had CRP values consistently below 10 mg/L while 16 had elevated CRP concentrations at least on one occasion ranging from 10 to 70 mg/L. Diagnoses other than bacterial infection could explain the raised CRP concentrations in neonates of group 2. CRP concentrations were found to be elevated (greater than 80 mg/L) during the course of infectious diseases in all neonates with proven bacterial infection (septicemia (4), pneumonia (1), multiple micro-abscesses (1), urinary tract infection (3]. Serial measurement of CRP concentrations are shown to be valuable in detecting bacterial infection in neonates as well as in following the efficacy of antimicrobial therapy.

Stability of norepinephrine infusions prepared in dextrose and normal saline solutions

Purpose: Norepinephrine (NE) infusions are commonly used in the intensive care unit and in the operating room. Data on long term stability of NE solutions are lacking. This prospective study was designed to evaluate the stability of NE, in dextrose (5%) in water (D5W) and in normal saline (NS) solutions, for a period up to seven days.Methods: We prepared norepinephrine solutions in quadruplicate, by aseptically diluting 1 mg NE in 250 mL of D5W or NS and 4 mg NE in 250 mL of D5W or NS (final concentrations, 4µg·mL−1 and 16µg·mL−1, respectively) and stored the solutions at room temperature under ambient light. We sampled the solutions, in duplicate, at times 0, 24, 48, 72, 120, and 168 hr and stored them at −80°C for later assay. Norepinephrine concentrations were measured by high-performance liquid chromatography with electrochemical detection (coefficient of variation 4.6%). Statistical analysis was done by nonparametric, repeated measures ANOVA (Friedman test).Results: There was no significant decrease in NE concentration for either, NE 4µg·mL−1 in D5W or NS (P=0.09 and 0.11, respectively) or for NE 16µg·mL−1 in D5W or NS (P=0.18 and 0.40, respectively). The ratios of NE concentration at 168 hr, compared to baseline, were 95.7% and 96.4%, for NE 4µg·mL−1 in D5W and NS, respectively, and 104.5% and 96.4%, for NE 16µg·mL−1 in D5W and NS, respectively.Conclusion: Norepinephrine solutions, in concentrations commonly used in the clinical setting, are chemically stable for seven days, at room temperature and under ambient light, when diluted either in D5W or NS.RésuméObjectif: Les perfusions de norépinéphrine (NE) sont fréquemment utilisées aux soins intensifs et en salle d’opération. Toutefois, les données concernant la stabilité à long terme des solutions de NE font défaut. Cette étude prospective a été conçue dans le but d’évaluer la stabilité de la NE préparée dans des solutions de dextrose (5 %) dans l’eau (D5W) et de chlorure de sodium 0,9 % (NS), pendant une durée maximale de sept jours.Méthode: Nous avons préparé des solutions de norépinéphrine en quatre exemplaires en diluant en milieu stérile 1 mg de NE dans 250 mL de D5W ou de NS et 4 mg de NE dans 250 mL de D5W ou de NS (concentrations finales de NE de 4 µg·mL−1 et de 16 µg·mL−1, respectivement). Nous avons stocké ces solutions à température et lumière ambiantes. Nous avons échantillonné les solutions en deux exemplaires à 0, 24, 48, 72, 120 et 168 h et les avons stockées à une température de −80°C pour fin d’analyses ultérieures. Les concentrations de norépinéphrine ont été mesurées par chromatographie liquide à haute performance avec une détection électrochimique (coefficient de variation 4,6 %). L’analyse statistique a été effectuée en utilisant une ANOVA (test de Friedman) pour mesures non paramétriques répétées.Résultats: Il n’y a eu de réduction significative dans la concentration de NE dans aucune des solutions, que ce soit NE 4 µg·mL−1 dans une solution de D5W ou de NS (P=0,09 et 0,11, respectivement) ou pour la solution de NE à 16 µg·mL−1 dans du D5W ou du NS (P=0,18 et 0,40, respectivement). Les ratios de concentration de norépinéphrine à 168 h, comparées aux données initiales, étaient de 95,7 % et 96,4 % pour la NE 4 µg·mL−1 dans les solutions de D5W et de NS, respectivement, et de 104,5 % et 96,4 % pour la NE 16 µg·mL−1 dans les solutions de D5W et de NS, respectivement.Conclusion: Les solutions de norépinéphrine, aux concentrations fréquemment utilisées dans un contexte clinique, sont chimiquement stables pour sept jours si elles sont conservées à température et lumière ambiantes, qu’elles soient diluées dans des solutions de D5W ou de NS.

A new rapid immunoinhibition pancreatic amylase assay: Diagnostic value for pancreatitis

A new rapid immunoinhibition pancreatic amylase assay was compared to total amylase and lipase in an unbiased sample of 1005 emergency department patients with suspicion of pancreatitis, of which 55 had a final diagnosis of pancreatitis. Imprecision of the assays for both amylases (less than 2.5%) were better than for lipase (less than 6.1%). Correlation (R2) of pancreatic amylase with total amylase was 0.991 but only 0.789 with lipase. Using Receiver Operator Characteristics analysis, the best diagnostic cutoff point for all three enzymes was near the upper limit of the reference interval. With pancreatic amylase, sensitivity, specificity, and predictive values for positive and negative results are, respectively, 85.5, 92.5, 39.8, and 99.1%; we found similar values for lipase but poorer values (78.2, 92.0, 36.1, and 98.7%) for total amylase. Tests combination did not improve the diagnostic performance significantly. In the diagnosis of pancreatitis, pancreatic amylase (p = 0.037) and lipase (p = 0.049) had better diagnostic performance than total amylase. The correct diagnosis of pancreatitis could be achieved in 47 instead of 43 patients with either pancreatic amylase or lipase as opposed to total amylase among 1005 patients in this study. We conclude that pancreatic amylase and lipase are incrementally better diagnostic tools than total amylase for the diagnosis of pancreatitis.

Ruptured aneurysmal subarachnoid hemorrhage in the emergency department: Clinical outcome of patients having a lumbar puncture for red blood cell count, visual and spectrophotometric xanthochromia after a negative computed tomography.

OBJECTIVES Over the last decade, computed tomography scanners have gained resolution and have become the standard of care in the investigation of neurologically intact patients suffering from acute headache. The added value of the combined assessment of red blood cells count, visual and spectrophotometric xanthochromia, to detect ruptured aneurysmal subarachnoid hemorrhage (ASAH) following a negative head computed tomography (NHCT) was studied. METHODS The population consisted of all patients who had cerebrospinal fluid tested for spectrophotometric xanthochromia between 2003 and 2009 identified through the clinical-laboratory database and who met all the inclusion criteria: >14 years old, had an initial Glasgow Coma Score of 15, a non-traumatic acute headache with a suspected subarachnoid hemorrhage recorded in the initial ED differential diagnosis and an initial negative head CT scan. RESULTS A total of 706 patients were included. LP identified 5 ASAH (prevalence: 0.7%). In these patients, LP parameters were as follows: high red blood cell count (from 1310 to 63,000×10(6)/L), positive visual xanthochromia in 4 out of 5 ASAH, and positive spectrophotometric xanthochromia in 5 out of 5 ASAH. All ASAH patients were neurologically intact after intervention. No deaths or missed ASAH were reported. Angiographies were performed on 127 patients (19.5%) of which 47 (34.1%) had positive xanthochromia (visual or spectrophotometric). CONCLUSIONS Considering the low prevalence of ASAH following an NHCT, intense resources were utilized to identify all 5 ASAH. Lumbar puncture analyses combining red blood cell count, visual and spectrophotometric xanthochromia identified all ASAH, allowing intervention and a positive clinical outcome. Our data support 1) that LP identifies the presence of a ruptured ASAH after an NHCT and 2)` that a guide to define a subpopulation of patients who would benefit from a lumbar puncture after an NHCT would be desirable.

In the Emergency Department, Are Serum Biomarkers useful to Screen Independent Frail Seniors Exposed to Future Functional Decline or Mobility Impairments after a Minor Injury?

Background: Frailty is a geriatric syndrome conferring a high risk of declining functional capacities. Some serum biomarkers are associated with frailty, but no study has specifically investigated the possible association between frailty and serum biomarkers in independent community-dwelling seniors who consulted the emergency department (ED) following a minor injury. Objective: 1) To explore baseline associations between six serum biomarkers and the frailty status of independent community-dwelling seniors who were seen in the ED for minor injuries, 2) to determine if ED serum biomarker assay combined with frailty status improves the prediction of 3-month functional decline or mobility impairments in this population, beyond frailty status alone. Methods: The study includes 190 participants (age ≥ 65 years, independent in daily activities and discharged home). Biomarkers were obtained at baseline from blood samples and values were identified as “normal” or “at risk”. Seniors were classified as “robust” or “pre-frail/frail” according to the CHSA-CFS and SOF scales. The seniors were screened for frailty at baseline (ED visit) while their functional status (OARS scale) and mobility characteristics (less than 5 outings/week and fear of falling) were assessed at the ED visit and three months later. Results: When compared to robust, a greater proportion of pre-frail/frail seniors had at-risk creatinine levels (p=0.02) at baseline. All the other biomarkers were not significant. In the prospective analysis, we found that having at least one at-risk biomarker slightly increased the prediction of 3-month mobility impairments in robust seniors (RR:0.44[0.10-1.91]). However, ED frailty status clearly remained the stronger predictor of future mobility impairments in pre-frail/frails having normal biomarkers (RR:3.11(0.98-9.84), p=0.007). Results were not significant for prospective functional decline. Conclusion: ED biomarker assays are not useful in predicting 3-month functional decline or mobility impairments beyond what is predicted by frailty status alone in independent community-dwelling seniors who consulted for minor injuries.