Flushing of an intravenous catheter: a cause for unreliable laboratory results

Introduction: Phlebotomy is an error-prone process in which mistakes are difficult to reveal. This case report describes the effect on laboratory results originating from a blood sample collected in close proximity to an intravenous catheter. Materials and methods: A 69-year-old male patient was referred to the Emergency department where pneumonia was suspected. Phlebotomy was performed to collect blood samples to assess electrolytes, renal function, liver function, infection and haematological parameters. Results: The laboratory analysis showed reduced potassium and calcium concentrations. To prevent life-threatening cardiac failure the clinician decided to correct those electrolytes. Remarkably, the electrocardiogram showed no abnormalities corresponding to hypokalaemia and hypocalcaemia. This observation, in combination with an overall increase in laboratory parameters with the exception of sodium and chloride, led to the suspicion of a preanalytical error. Retrospectively, an intravenous catheter was inserted in close proximity of the puncture place but no continuous infusion was started prior to phlebotomy. However, the intravenous catheter was flushed with sodium chloride. Since potential other causes were excluded, the flushing of the intravenous catheter with sodium chloride prior to phlebotomy was the most probable cause for the deviating laboratory results and subsequently for the unnecessary potassium and calcium suppletion. Conclusion: This case underlines the importance of caution in the interpretation of laboratory results obtained from specimens that are collected in the proximity of an intravenous catheter, even in the absence of continuous infusion

The impact of regionalized trauma care on the distribution of severely injured patients in the Netherlands

BACKGROUND: Twenty years ago, an inclusive trauma system was implemented in the Netherlands. The goal of this study was to evaluate the impact of structured trauma care on the concentration of severely injured patients over time. METHODS: All severely injured patients (Injury Severity Score [ISS] ≥ 16) documented in the Dutch Trauma Registry (DTR) in the calendar period 2008–2018 were included for analysis. We compared severely injured patients, with and without severe neurotrauma, directly brought to trauma centers (TC) and non-trauma centers (NTC). The proportion of patients being directly transported to a trauma center was determined, as was the total Abbreviated Injury Score (AIS), and ISS. RESULTS: The documented number of severely injured patients increased from 2350 in 2008 to 4694 in 2018. During this period, on average, 70% of these patients were directly admitted to a TC (range 63–74%). Patients without severe neurotrauma had a lower chance of being brought to a TC compared to those with severe neurotrauma. Patients directly presented to a TC were more severely injured, reflected by a higher total AIS and ISS, than those directly transported to a NTC. CONCLUSION: Since the introduction of a well-organized trauma system in the Netherlands, trauma care has become progressively centralized, with more severely injured patients being directly presented to a TC. However, still 30% of these patients is initially brought to a NTC. Future research should focus on improving pre-hospital triage to facilitate swift transfer of the right patient to the right hospital

Evaluation of the Berlin polytrauma definition:A Dutch nationwide observational study

BACKGROUND The Berlin polytrauma definition (BPD) was established to identify multiple injury patients with a high risk of mortality. The definition includes injuries with an Abbreviated Injury Scale score of >= 3 in >= 2 body regions (2AIS >= 3) combined with the presence of >= 1 physiological risk factors (PRFs). The PRFs are based on age, Glasgow Coma Scale, hypotension, acidosis, and coagulopathy at specific cutoff values. This study evaluates and compares the BPD with two other multiple injury definitions used to identify patients with high resource utilization and mortality risk, using data from the Dutch National Trauma Register (DNTR). METHODS The evaluation was performed based on 2015 to 2018 DNTR data. First, patient characteristics for 2AIS >= 3, Injury Severity Score (ISS) of >= 16, and BPD patients were compared. Second, the PRFs prevalence and odds ratios of mortality for 2AIS >= 3 patients were compared with those from the Deutsche Gesellschaft fur Unfallchirurgie Trauma Register. Subsequently, the association between PRF and mortality was assessed for 2AIS >= 3-DNTR patients and compared with those with an ISS of >= 16. RESULTS The DNTR recorded 300,649 acute trauma admissions. A total of 15,711 patients sustained an ISS of >= 16, and 6,263 patients had suffered a 2AIS >= 3 injury. All individual PRFs were associated with a mortality of >30% in 2AIS >= 3-DNTR patients. The increase in PRFs was associated with a significant increase in mortality for both 2AIS >= 3 and ISS >= 16 patients. A total of 4,264 patients met the BPDs criteria. Overall mortality (27.2%), intensive care unit admission (71.2%), and length of stay were the highest for the BPD group. CONCLUSION This study confirms that the BPD identifies high-risk patients in a population-based registry. The addition of PRFs to the anatomical injury scores improves the identification of severely injured patients with a high risk of mortality. Compared with the ISS >= 16 and 2AIS >= 3 multiple injury definitions, the BPD showed to improve the accuracy of capturing patients with a high medical resource need and mortality rate

Flushing of an intravenous catheter: a cause for unreliable laboratory results

Introduction: Phlebotomy is an error-prone process in which mistakes are difficult to reveal. This case report describes the effect on laboratory results originating from a blood sample collected in close proximity to an intravenous catheter. Materials and methods: A 69-year-old male patient was referred to the Emergency department where pneumonia was suspected. Phlebotomy was performed to collect blood samples to assess electrolytes, renal function, liver function, infection and haematological parameters. Results: The laboratory analysis showed reduced potassium and calcium concentrations. To prevent life-threatening cardiac failure the clinician decided to correct those electrolytes. Remarkably, the electrocardiogram showed no abnormalities corresponding to hypokalaemia and hypocalcaemia. This observation, in combination with an overall increase in laboratory parameters with the exception of sodium and chloride, led to the suspicion of a preanalytical error. Retrospectively, an intravenous catheter was inserted in close proximity of the puncture place but no continuous infusion was started prior to phlebotomy. However, the intravenous catheter was flushed with sodium chloride. Since potential other causes were excluded, the flushing of the intravenous catheter with sodium chloride prior to phlebotomy was the most probable cause for the deviating laboratory results and subsequently for the unnecessary potassium and calcium suppletion. Conclusion: This case underlines the importance of caution in the interpretation of laboratory results obtained from specimens that are collected in the proximity of an intravenous catheter, even in the absence of continuous infusion

Characterization of epitope-specific anti-RSV antibody responses after natural infection and after vaccination with formalin-inactivated RSV

Antibodies against the fusion (F) protein of respiratory syncytial virus (RSV) play an important role in the protective immune response against this important respiratory virus. Little is known, however, about antibody levels against multiple F-specific epitopes induced by infection or after vaccination against RSV, while this is important to guide the evaluation of (novel) vaccines. In this study we analyzed antibody levels against RSV proteins and F-specific epitopes in human sera and in sera of vaccinated and experimentally-infected cotton rats; and the correlation thereof with virus neutralization. Analysis of human sera revealed substantial diversity in antibody levels against F-, G (attachment)-, and F-specific epitopes between individuals. The highest correlation with virus neutralization was observed for antibodies recognizing prefusion-specific antigenic site Ø. Nevertheless, our results indicate that high levels of antibodies targeting other parts of the F protein can also mediate a potent antiviral antibody response. In agreement herewith, sera of experimentally infected cotton rats contained high neutralizing activity although lacking antigenic site Ø-specific antibodies. Strikingly, vaccination with formalin-inactivated (FI)-RSV exclusively resulted in the induction of poorly neutralizing antibodies against postfusion-specific antigenic site I, although antigenic sites I, II and IV were efficiently displayed in FI-RSV. The apparent immunodominance of antigenic site I in FI-RSV likely explains the low levels of neutralizing antibodies upon vaccination and challenge, and may play a role in the vaccination-induced enhancement of disease observed with such preparations. IMPORTANCE: RSV is an importance cause of hospitalization in infants. The development of a vaccine against RSV has been hampered by the disastrous results obtained with FI-RSV vaccine preparations in the 1960s that resulted in vaccination-induced enhancement of disease. To get a better understanding of the antibody repertoire induced after infection or after vaccination against RSV, we investigated antibody levels against fusion (F), attachment (G) protein and F-specific epitopes in human and animal sera. The results indicate the importance of prefusion-specific antigenic site Ø antibodies as well as of antibodies targeting other epitopes in virus neutralization. However, vaccination of cotton rats with FI-RSV specifically resulted in the induction of weakly-neutralizing, antigenic site I-specific antibodies, which may play a role in the enhancement of disease observed after vaccination with such preparations

Surgery versus conservative treatment in patients with type A distal radius fractures, a randomized controlled trial

Fractures of the distal radius are common and account for an estimated 17% of all fractures diagnosed. Two-thirds of these fractures are displaced and require reduction. Although distal radius fractures, especially extra-articular fractures, are considered to be relatively harmless, inadequate treatment may result in impaired function of the wrist. Initial treatment according to Dutch guidelines consists of closed reduction and plaster immobilisation. If fracture redisplacement occurs, surgical treatment is recommended. Recently, the use of volar locking plates has become more popular. The aim of this study is to compare the functional outcome following surgical reduction and fixation with a volar locking plate with the functional outcome following closed reduction and plaster immobilisation in patients with displaced extra-articular distal radius fractures. This single blinded randomised controlled trial will randomise between open reduction and internal fixation with a volar locking plate (intervention group) and closed reduction followed by plaster immobilisation (control group). The study population will consist of all consecutive adult patients who are diagnosed with a displaced extra-articular distal radius fracture, which has been adequately reduced at the Emergency Department. The primary outcome (functional outcome) will be assessed by means of the Disability Arm Shoulder Hand Score (DASH). Secondary outcomes comprise the Patient-Rated Wrist Evaluation score (PRWE), quality of life, pain, range of motion, radiological parameters, complications and cross-overs. Since the treatment allocated involves a surgical procedure, randomisation status will not be blinded. However, the researcher assessing the outcome at one year will be unaware of the treatment allocation. In total, 90 patients will be included and this trial will require an estimated time of two years to complete and will be conducted in the Academic Medical Centre Amsterdam and its partners of the regional trauma care network. Ideally, patients would be randomised before any kind of treatment has been commenced. However, we deem it not patient-friendly to approach possible participants before adequate reduction has been obtained. This study is registered at the Netherlands Trial Register (NTR3113) and was granted permission by the Medical Ethical Review Committee of the Academic Medical Centre on 01-10-201

Schematic representation of the different recombinant soluble RSV F protein constructs.

<p>RSV F proteins lacking the transmembrane domain (TM) and cytoplasmic tail (CT) were genetically fused to a CD5 signal peptide (CD5) and to a carboxy-terminal tag (tag). When indicated a GCN4 trimerization motif (GCN) was introduced between the F protein and the tag. The tag either consisted of a triple Strep-tagII, a LysM peptidoglycan binding domain, or of a combination of the two (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0071072#pone.0071072.s001" target="_blank">Fig. S1</a>). The F2 and F1 subunits of F are indicated, as well as the p27 peptide (P27) that is released after furin cleavage. Protease cleavage sites are indicated by black arrows. Grey arrows indicate mutated furin cleavage sites. The approximate location of the fusion peptide (FP), heptad repeat A (HRA) and B (HRB) is also shown.</p

Reactivity of recombinant F proteins with neutralizing antibodies.

<p>A) ELISA analysis of recombinant F proteins. Purified F proteins were coated on 96-well plates; when indicated samples were treated with TPCK trypsin (+ T) prior to coating. The reactivity of the recombinant proteins with different neutralizing MAbs was analyzed by applying 2-fold serial dilutions of Palivizumab (starting with 0.375 µg/ml), AM22 (starting with 3.5 µg/ml) or D25 (starting with 5 µg/ml). Binding of the antibodies was detected using HRP-conjugated secondary antibodies. Fwt-GCN and Flys-GCN contain a C-terminal LysM domain and ST3 tag. Fwt and Flys contain a C-terminal ST3 tag. B) Neutralization of RSV by MAbs. The amount needed of each MAb to achieve 50% neutralization of virus infectivity is graphed. The error bars indicate the standard deviations (* P<0.05 in Student’s t test).</p

Binding of recombinant F proteins to BLPs.

<p>A) Binding efficacy of the various F proteins (Fwt, Fwt-GCN, Flys, and Flys-GCN; all carrying a C-terminal LysM domain, but no ST3 tag) to BLPs was determined by incubation of an equal amount (28 µg) of the F proteins with 1 mg of BLPs using standard conditions. The amount of F protein bound to the BLPs was determined by comparative SDS-PAGE analysis in which Colloidal Blue staining of F proteins was compared with that of BSA standards. B) To analyze the binding pattern of F to BLPs, BLPs carrying Flys-GCN with a LysM domain (BLP-F) were generated using standard conditions followed by incubation with Palivizumab and FITC-labeled goat-anti-human secondary antibodies. As a control “empty” BLPs were used. The preparations were analyzed using bright field and fluorescence microscopy. C) BLPs displaying Fwt-GCN or Flys-GCN were analyzed using bright field microscopy.</p

Immunization and challenge studies in mice.

<p>Mice were (mock-)vaccinated three times either intranasally with BLP-F (○) or PBS (▪) or intramuscularly with FI-RSV (•) with 14 day intervals followed by a challenge with RSV/A/long (10⁶ pfu) at 14 days after the last vaccination. A) F-specific IgG titers before immunization (day 0) and 2 weeks after each immunization (days 14, 28 and 42). B) RSV neutralization titers after three immunizations (serum pool of all animals of each group, day 42). C) Virus titers in the lungs at 5 days after challenge. The limit of detection is 200 pfu/gr. D) 5 days post challenge the lungs were harvested for pulmonary histopathology examination. Interstitial pneumonia and alveolitis were scored as described in the Materials and Methods. Standard error of the mean (SEM) is indicated by the error bars. The group receiving BLP-F was compared with the other groups on day 42 using a Mann-Whitney U test (* P≤0.05 ).</p