Blood Culture Ordering After Sepsis Alerts and Subsequent Patient Outcomes: An Electronic Health Record-Based Study

Sepsis is a global health priority associated with high mortality. Clinical decision support systems have been developed to support clinicians with sepsis management. Ordering blood cultures (BCs) for suspected sepsis patients are strongly recommended by clinical guidelines. However, limited evidence exists investigating BC ordering following sepsis alerts and subsequent patient outcomes. This study aimed to investigate this issue using electronic health record data from an acute care hospital in Australia. Of 4,092 patients, only 16.6% had a BC ordered following a sepsis alert. The median time from the first sepsis alert to a BC order was 15.3 hours. Patients had 5.89 times higher odds of being diagnosed with sepsis if a BC was ordered following a sepsis alert than those without BC ordered (p<0.0001). Further investigation is needed to understand reasons behind the delay or failure to order a BC despite receiving electronic sepsis alerts and how decision support can be optimized to improve patient outcomes.

Comparison of the quick Sepsis-related Organ Failure Assessment and adult sepsis pathway in predicting adverse outcomes among adult patients in general wards: a retrospective observational cohort study

BACKGROUND

Quick Sepsis-related Organ Failure Assessment (qSOFA) is recommended for use by the most recent international sepsis definition taskforce to identify suspected sepsis in patients outside the intensive care unit (ICU) at risk of adverse outcomes. Evidence of its comparative effectiveness with existing sepsis recognition tools is important to guide decisions about its widespread implementation.

AIM

To compare the performance of qSOFA with the adult sepsis pathway (ASP), a current sepsis recognition tool widely used in NSW hospitals and systemic inflammatory response syndrome criteria in predicting adverse outcomes in adult patients on general wards.

METHODS

A retrospective observational cohort study was conducted which included all adults with suspected infections admitted to a Sydney teaching hospital between December 2014 and June 2016. The primary outcome was in-hospital mortality with two secondary composite outcomes.

RESULTS

Among 2940 patients with suspected infection, 217 (7.38%) died in-hospital and 702 (23.88%) were subsequently admitted to ICU. The ASP showed the greatest ability to correctly discriminate in-hospital mortality and secondary outcomes. The area under the receiver-operating characteristic curve for mortality was 0.76 (95% confidence interval (CI): 0.74-0.78), compared to 0.64 for the qSOFA tool (95% CI: 0.61-0.67, P < 0.0001). Median time from the first ASP sepsis warning to death was 8.21 days (interquartile range (IQR): 2.29-16.75) while it was 0 days for qSOFA (IQR: 0-2.58).

CONCLUSIONS

The ASP demonstrated both greater prognostic accuracy and earlier warning for in-hospital mortality for adults on hospital wards compared to qSOFA. Hospitals already using ASP may not benefit from switching to the qSOFA tool.

Reduction of in-hospital cardiac arrest rates in intensive care-equipped New South Wales hospitals in association with implementation of Between the Flags rapid response system

BACKGROUND

The NSW Clinical Excellence commission introduced the 'Between the Flags' programme, in response to the death of a young patient, as a system-wide approach for early detection and management of the deteriorating patient in all NSW hospitals. The impact of BTF implementation on the 35 larger hospitals with intensive care units (ICU) has not been reported previously.

AIM

To assess the impact of 'Between the Flags' (BTF), a two-tier rapid response system across 35 hospitals with an ICU in NSW, on the incidence of in-hospital cardiac arrests and the incidence and outcome of patients admitted to an ICU following cardiac arrest and rapid response team activation.

METHODS

This is a prospective observational study of the BTF registry (August 2010 to June 2016) and the Australian and New Zealand Intensive Care Society Adult Patient Database (January 2008 to December 2016) in 35 New South Wales public hospitals with an ICU. The primary outcome studied was the proportion of in-hospital cardiac arrests. Secondary outcomes included changes in the severity of illness and outcomes of cardiac arrest admissions to the ICU and changes in the volume of rapid response calls.

RESULTS

The cardiac arrest rate per 1000 hospital admissions declined from 0.91 in the implementation period to 0.70. Propensity score analysis showed significant declines in ICU and hospital mortality and length of stay for cardiac arrest patients admitted to the ICU (all P < 0.001).

CONCLUSIONS

The BTF programme was associated with a significant reduction in cardiac arrests in hospitals and ICU admissions secondary to cardiac arrests in 35 NSW hospitals with an ICU.

Evaluation of an augmented emergency department electronic medical record-based sepsis alert

OBJECTIVE

Electronic medical records-based alerts have shown mixed results in identifying ED sepsis. Augmenting clinical patient-flagging with automated alert systems may improve sepsis screening. We evaluate the performance of a hybrid alert to identify patients in ED with sepsis or in-hospital secondary outcomes from infection.

METHODS

We extracted a dataset of all patients with sepsis during the study period at five participating Western Sydney EDs. We evaluated the hybrid alert's performance for identifying patients with a discharge diagnosis related to infection and modified sequential sepsis-related organ functional assessment (mSOFA) score ≥2 in ED and also compared the alert to rapid bedside screening tools to identify patients with infection for secondary outcomes of all-cause in-hospital death and/or intensive care unit admission.

RESULTS

A total of 118 178 adult patients presented to participating EDs during study period with 1546 patients meeting ED sepsis criteria. The hybrid alert had a sensitivity - 71.2% (95% confidence interval 68.8-73.4), specificity - 96.4% (95% confidence interval 96.3-96.5) for identifying ED sepsis. Clinician flagging identified additional alert-negative 232 ED sepsis and 63 patients with secondary outcomes and 112 alert-positive patients with infection and ED mSOFA score <2 went on to die in hospital.

CONCLUSION

The hybrid alert performed modestly in identifying ED sepsis and secondary outcomes from infection. Not all infected patients with a secondary outcome were identified by the alert or mSOFA score ≥2 threshold. Augmenting clinical practice with auto-alerts rather than pure automation should be considered as a potential for sepsis alerting until more reliable algorithms are available for safe use in clinical practice.

Improving the Performance of Clinical Decision Support for Early Detection of Sepsis: A Retrospective Observational Cohort Study

Sepsis remains a significant global health problem. It is a life-threatening, but poorly defined and recognized condition. Early recognition and intervention are essential to optimize patient outcomes. Automated clinical decision support systems (CDS) may be particularly beneficial for early detection of sepsis. The aim of this study was to use retrospective data to develop and evaluate seven revised versions of an electronic sepsis alert rule to assess their performance in detecting sepsis cases and patient deterioration (in-hospital mortality or ICU admission). Four revised options had higher sensitivity but lower specificity than the original rule. After discussion with clinical experts, two revised options with the highest sensitivity were selected. Further analysis on the number of alerts and time intervals between alerts and patient outcomes was conducted to decide the option to be implemented. This study has provided a data-driven approach to improve the CDS on early detection of sepsis.

Lactate ≥2 mmol/L plus qSOFA improves utility over qSOFA alone in emergency department patients presenting with suspected sepsis

OBJECTIVE

The Sepsis-3 task force recommends the use of the quick Sequential Organ Failure Assessment (qSOFA) score to identify risk for adverse outcomes in patients presenting with suspected infection. Lactate has been shown to predict adverse outcomes in patients with suspected infection. The aim of the study is to investigate the utility of a post hoc lactate threshold (≥2 mmol/L) added qSOFA score (LqSOFA₍₂₎ score) to predict primary composite adverse outcomes (mortality and/or ICU stay ≥72 h) in patients presenting to ED with suspected sepsis.

METHODS

Retrospective cohort study was conducted on a merged dataset of suspected or proven sepsis patients presenting to ED across multiple sites in Australia and The Netherlands. Patients are identified as candidates for quality improvement initiatives or research studies at respective sites based on local screening procedures. Data-sharing was performed across sites of demographics, qSOFA, SOFA, lactate thresholds and outcome data for included patients. LqSOFA₍₂₎ scores were calculated by adding an extra point to qSOFA score in patients who met lactate thresholds of ≥2 mmol/L.

RESULTS

In a merged dataset of 12 555 patients where a full qSOFA score and outcome data were available, LqSOFA₍₂₎ ≥2 identified more patients with an adverse outcome (sensitivity 65.5%, 95% confidence interval 62.6-68.4) than qSOFA ≥2 (sensitivity 47.6%, 95% confidence interval 44.6- 50.6). The post hoc addition of lactate threshold identified higher proportion of patients at risk of adverse outcomes.

CONCLUSIONS

The lactate ≥2 mmol/L threshold-based LqSOFA₍₂₎ score performs better than qSOFA alone in identifying risk of adverse outcomes in ED patients with suspected sepsis.

Serum lactate cut-offs as risk stratification tool for in-hospital adverse outcomes in emergency department patients screened for suspected sepsis

OBJECTIVES

We investigated specific lactate thresholds for adverse outcomes in patients presenting to emergency departments (EDs) with suspected sepsis identified based on the performance of a sepsis screening algorithm.

DESIGN AND SETTING

A standardised sepsis bundle was implemented across public hospitals in New South Wales, Australia, as a quality improvement initiative. A register of all adult ED presentations (≥18 years) meeting predefined criteria for sepsis was created, using a combination of data linkage and direct reporting from 97 participating sites.

PARTICIPANTS

A total of 12 349 adult ED presentations with 8310 (67.3%) having serum lactate analysis on arrival. Analysis of outcomes was based on dataset for 12 349 subjects obtained through multiple imputation for missing data.

INTERVENTIONS

A sepsis management bundle including early antibiotic prescribing, fluid therapy and referral to intensive care unit (ICU) services was implemented.

OUTCOME MEASURES

A primary composite adverse event (AE) outcome of inhospital mortality (IHM) and/or prolonged ICU stay ≥72 hours (ICU 72 hours) was used for this study.

RESULTS

There was statistically significant increase both in the ORs of AE and IHM with each integer increase in serum lactate values. After adjusting for the presence of hypotension, the estimated ORs for the combined AE outcome were 2.71 (95% CI 2.05 to 3.57), 2.65 (95% CI 2.29 to 3.08), 3.10 (95% CI 2.71 to 3.53) and 3.89 (95% CI 3.36 to 4.50) for serum lactate levels at or above 1, 2, 3 and 4 mmol/L, respectively. The corresponding ORs for IHM were 2.93 (95% CI 2.08 to 4.13), 2.77 (95% CI 2.34 to 3.29), 3.26 (95% CI 2.80 to 3.80) and 4.01 (95% CI 3.40 to 4.73), respectively (all P<0.0001). More than 10% of patients with suspected sepsis and with serum lactate ≥2 mmol/L experienced a prolonged ICU stay or died in hospital.

CONCLUSIONS

ED sepsis screening algorithms intended to identify patient adverse outcomes should incorporate a serum lactate cut-off of ≥2 mmol/L as a threshold for the initiation of specific interventions and increased monitoring.

Comparison of the Between the Flags calling criteria to the MEWS, NEWS and the electronic Cardiac Arrest Risk Triage (eCART) score for the identification of deteriorating ward patients

INTRODUCTION

Traditionally, paper based observation charts have been used to identify deteriorating patients, with emerging recent electronic medical records allowing electronic algorithms to risk stratify and help direct the response to deterioration.

OBJECTIVE(S)

We sought to compare the Between the Flags (BTF) calling criteria to the Modified Early Warning Score (MEWS), National Early Warning Score (NEWS) and electronic Cardiac Arrest Risk Triage (eCART) score.

DESIGN AND PARTICIPANTS

Multicenter retrospective analysis of electronic health record data from all patients admitted to five US hospitals from November 2008-August 2013.

MAIN OUTCOME MEASURES

Cardiac arrest, ICU transfer or death within 24h of a score RESULTS: Overall accuracy was highest for eCART, with an AUC of 0.801 (95% CI 0.799-0.802), followed by NEWS, MEWS and BTF respectively (0.718 [0.716-0.720]; 0.698 [0.696-0.700]; 0.663 [0.661-0.664]). BTF criteria had a high risk (Red Zone) specificity of 95.0% and a moderate risk (Yellow Zone) specificity of 27.5%, which corresponded to MEWS thresholds of >=4 and >=2, NEWS thresholds of >=5 and >=2, and eCART thresholds of >=12 and >=4, respectively. At those thresholds, eCART caught 22 more adverse events per 10,000 patients than BTF using the moderate risk criteria and 13 more using high risk criteria, while MEWS and NEWS identified the same or fewer.

CONCLUSION(S)

An electronically generated eCART score was more accurate than commonly used paper based observation tools for predicting the composite outcome of in-hospital cardiac arrest, ICU transfer and death within 24h of observation. The outcomes of this analysis lend weight for a move towards an algorithm based electronic risk identification tool for deteriorating patients to ensure earlier detection and prevent adverse events in the hospital.

New sepsis definition changes incidence of sepsis in the intensive care unit

OBJECTIVE

To estimate the impact of adopting the proposed new diagnostic criteria for sepsis, based on Sequential Organ Failure Assessment (SOFA) criteria, on the diagnosis and apparent mortality of sepsis in Australian and New Zealand intensive care units.

DESIGN, SETTING AND PARTICIPANTS

A two-stage, post hoc analysis of prospectively collected ICU research data from 3780 adult patients in 77 Australian and New Zealand ICUs on 7 study days, between 2009 and 2014.

MAIN OUTCOME MEASURES

The proportion of patients who were diagnosed with sepsis using the criteria for systemic inflammatory response syndrome (SIRS) and who met the SOFA criteria for sepsis, and the proportion of patients who were admitted to the ICU with a diagnosis consistent with infection, who met either, both or neither sets of criteria for sepsis; comparison of the demographic differences and in-hospital mortality between these groups.

RESULTS

Of 926 patients diagnosed with sepsis on a study day using SIRS criteria, 796/923 (86.2% [95% CI, 84.0%-88.5%]) satisfied the SOFA criteria. Inhospital mortality was similar in these groups, with death recorded for 216/872 patients (24.8% [95% CI, 21.9%-27.8%]) who met the SIRS criteria for sepsis, and for 200/747 patients (26.8% [95% CI, 23.6%-30.1%]) who met both the SIRS and SOFA criteria for sepsis. Of 122 patients meeting the SIRS criteria but not the SOFA criteria, 16 (13.1% [95% CI, 7.7%-19.1%]) died. Of 241 patients admitted with an infective condition and complete data, 142 (58.9% [95% CI, 52.4%-65.2%]) satisfied the SIRS criteria for sepsis and 210 (87.1% [95% CI, 82.2%-91.1%]) satisfied the SOFA criteria. Of the 241 patients, 99 (41.1%) were not classified as having sepsis on the study day by SIRS criteria and, of these, 80 (80.8%) met the SOFA criteria.

CONCLUSIONS

Adopting the SOFA criteria will increase the apparent incidence of sepsis in patients admitted to the ICU with infective conditions without affecting the mortality rate. Prospective evaluation of the effect of adopting the new definition of sepsis is required.

Intensive dietary intervention by a dietitian as a case manager among community dwelling older adults: the EDIT study

BACKGROUND

Clinical trials that have assessed the best approach for treating under-nutrition in old age are scarce.

OBJECTIVE

To determine the impact of an intensive nutritional intervention program led by a dietitian on the health and nutritional status of malnourished community dwelling older adults.

METHODS

Sixty-eight eligible participants (age<75) were randomly assigned to a Dietetic Intervention Treatment (DIT), an intensive nutritional intervention led by a dietitian, or a Medical Treatment (MT), a physician-led standard care group, with an educational booklet regarding dietary requirements and recommendations for older adults. An additional 59 eligible participants who were unable to participate in the randomization were included as a non-randomized "untreated nutrition" group (UNG).

RESULTS

Over the 6-month follow-up, the DIT group showed significant improvement in cognitive function (from 25.8±4.5 to 26.8±4, p=0.04), and depression score (from 7.3±3.9 to 5.4±3.9, p=0.04) compared with the change in the other 2 groups. The DIT group showed a significant improvement in intake of carbohydrates (+15% vs. +1% in the MT and +3% in the UNG), protein (+8% vs. +2% in the MT and -3% in the UNG), vitamin B6 (+20% vs. +7% in the MT and +8% in the UNG), and vitamin B1 (+22% vs. +11% in the MT and 0% in the UNG). The DIT group had a significantly lower cost of physician visits than the other 2 groups ($172.1±232.0 vs. $417.2±368.0 in the MT and $428.1±382.3 in the UNG, p=0.005).

CONCLUSION

Intensive dietary intervention was moderately effective in lowering cost of services used and improving medical and nutritional status among community dwelling older adults.

v-Crk modulation of growth factor-induced PC12 cell differentiation involves the Src homology 2 domain of v-Crk and sustained activation of the Ras/mitogen-activated protein kinase pathway

Nerve growth factor (NGF) and epidermal growth factor (EGF) elicit contrasting actions on PC12 pheochromocytoma cells; NGF causes neuronal differentiation, and EGF induces proliferation. However, ectopic expression of the Src homology 2 (SH2) and SH3-containing oncogenic adaptor protein v-Crk in PC12 cells results in EGF-inducible neuronal differentiation (Hempstead, B. L., Birge, R. B., Fajardo, J. E., Glassman, R., Mahadeo, D., Kraemer, R., and Hanafusa, H. (1994) Mol. Cell. Biol. 14, 1964-1971). Here we show that v-Crk complexes with both the tyrosine-phosphorylated EGF receptor and the Ras guanine nucleotide exchange factor SOS in PC12 cells and is involved in an pathway analogous to that of Grb2. Expression of v-Crk results in an enhanced and sustained activation of Ras and mitogen-activated protein (MAP) kinase following EGF or NGF stimulation, implying that v-Crk can couple divergent tyrosine kinase pathways to Ras. To investigate the causal relationship between EGF receptor binding, MAP kinase activation, and neurite outgrowth, we stably expressed two v-Crk SH2 point mutants, v-Crk(R273N) and v-Crk(H294R) in PC12 cells. Mutations within the SH2 domain of v-Crk block binding of v-Crk to the tyrosine phosphorylated EGF receptor, compromise v-Crk's ability to cause EGF-dependent neurite outgrowth, and act in a dominant negative manner for NGF-induced neurite outgrowth. However, the kinetics of MAP kinase activation in EGF- or NGF-treated v-Crk-(R273N)PC12 cells was comparable with that in v-CrkPC12 cells. These data are consistent with a model in which v-Crk regulates the strength of a tyrosine kinase signal leading to prolonged activation of Ras and MAP kinase. However, the experiments with the SH2 mutants suggest that sustained activation, by itself, may not be sufficient to switch the fate of v-CrkPC12 cells from proliferation toward differentiation.

The effect of lipoproteins on human glioblastoma growth in vitro

Experiments were performed using an established human glioblastoma cell line to determine the effect of lipoproteins on regulating their growth. It was found that synthetic and natural human high density lipoproteins (HDL) were effective in inhibiting tumor cell growth in a nontoxic, dose-dependent manner, and that the LD50 was 10-fold lower than that for normal rat astrocytes grown under identical conditions. In the presence of the antioxidant, glutathione, essentially all of the growth-inhibiting properties of HDL could be reversed suggesting that oxidized lipids from the HDL interacting with the plasma membranes of the glioblastoma cells were responsible for the growth-inhibiting effect observed. The markedly lower concentration of HDL required to inhibit glioblastoma cells in culture compared to normal astrocytes suggested that the mechanism of HDL-induced inhibition may be important for tumor growth in vivo. One possible mechanism under investigation is the possibility of HDL modulation of a membrane-associated, tumor-specific phosphatase.

School of medicine's uncertain future

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Cis-platinum treatment of metastatic adrenal carcinoma

Cis-platinum was used in the management of four patients with metastatic carcinoma of the adrenal cortex. In each instance, clinical and objective response was observed. This agent would appear to warrant further trial in the management of this rare tumour.

Pseudodelirium

Two case histories are presented which illustrate the fact that acute functional psychoses may simulate delirium. It is suggested that the term "pseudodelirium" may alert clinicians to this possibility, and facilitate the earlier diagnosis and treatment of psychiatric illness.

Null cell chronic lymphocytic leukaemia

Lymphocytes lacking receptors for sheep erythrocytes and surface immunoglobulin were present in the blood in large numbers at some stage in four cases of chronic lymphocytic leukaemia (which included a mother and son), and formed a substantial proportion of the circulating lymphocytes in other cases. These null cells possessed receptors for mouse erythrocytes. Other B-cell markers were also found on these cells. Serial studies showed a great variation in the number of null cells during the course of the disease (which may be associated with treatment), suggesting variation in the the maturation of leukaemic cells, and indicating that the surface marker complement may not reflect the constitution of the cell undergoing the original malignant change.

A retrospective analysis of the TATs of children at risk who subsequently broke down

A retrospective evaluation of stories told to three Thematic Apperception Test (TAT) cards by children at risk isolated six characteristics that were associated with functioning six to 10 years later. The characteristics included lack of individual initiative, denial of mother-child relationships, denial of negative outcomes, and lack of autonomy. The TATs of children at risk (due to one parent's hospitalization for a psychotic illness) who subsequently suffered major decompensation themselves (requiring hospitalization or intensive outpatient therapy) could be discriminated from those of children at risk with apparently normal development. The TAT characteristics were independent of the level of adjustment at the time the TATs were administered, not related to the child's IQ, socioeconomic status, race, or other family characteristics, and moderately negatively correlated with story length.

Platelet metal levels in normal subjects determined by atomic absorption spectrophotometry

A method has been developed for the estimation of iron, copper, zinc, calcium and magnesium in human platelets using atomic absorption spectrophotometry. Fe and Cu are either absent or present in very low concentration approaching the limit of detection: Zn, Ca and Mg are readily detectable. EDTA is preferable to ACD(A) or heparin as the anticoagulant for collection in that the platelet yield is reliable: however, slightly low results for Ca and Mg are obtained. Corrections for residual plasma and contaminating red cells are essential. Plasma and platelet metal levels in 33 normal subjects are reported together with the findings in four studies undertaken on platelets obtained from subjects with polycythemia vera.

Technetium-99m-pyridoxylideneglutamate: a new hepatobiliary radiopharmaceutical. II. Clinical aspects

Technetium-99m-pyridoxylideneglutamate (99mTc-PG) is a nontoxic radiopharmaceutical that was found to undergo rapid biliary excretion in normal humans. The biliary tree and gallbladder were seen within 10-15 min of injection and by 20 min marked accumulation of radioactivity was noted in the gallbladder and gastrointestinal tract. Of ten "control" volunteers, seven had normal 99mTc-PG-cholescintigrams. In the remaining three, the gallbladder was not visualized. Gallbladder disease was not excluded in these three subjects. Of 24 patients referred for investigation of right upper quadrant abdominal pain, 13 proved to have gallbladder disease. All seven patients with acute cholecystitis and one of four patients with chronic cholecystitis had nonvisualization of the gallbladder on the cholescintigram whereas five patients with chronic cholecystitis or cholesterolosis had normal cholescintigrams. Six of the eight patients with nonvisualization of the gallbladder on cholescintigram had contrast radiologic studies (oral cholecystogram or intravenous cholangiogram or both), and in all six, nonvisualization of the gallbladder was also reported on the contrast study. cholescintigraphy was found to be greatly inferior to contrast radiologic studies in the detection of gallbladder stones. Eleven patients had complete extrahepatic biliary obstruction and this diagnosis was correctly made in all 11 by the cholescintigram. Fourteen patients had incomplete extrahepatic biliary obstruction. The correct diagnosis was made on the cholescintigram in seven but in the remaining seven it was not possible to distinguish between incomplete extrahepatic biliary obstruction and hepatocellular disease. Malignant lesions (carcinomas of head of pancreas, gallbladder, common bile duct or ampulla of Vater) were the cause of obstruction in 10 of the 25 patients with complete or incomplete obstruction and the diagnosis of obstruction due to malignancy was correctly made in 8 of these 10 by means of a scintigraphic equivalent to Courvoisier's sing. Finally, 11 patients had hepatocellular disease and a nonspecific pattern consistent with either imcomplete biliary obstruction or hepatocellular disease was observed on the cholescintigram in all 11. The 99mTc-PG cholescintigram is suggested for a role complementary to that of contrast radiologic studies in the preoperative investigation of patients with possible surgical disease of the biliary tract. Contrast radiologic techniques are advocated as being more appropriate in the nonjaundiced patient with suspected gallbladder disease whereas the 99mTc-PG cholescintigram is advocated as being more appropriate in the patient with jaundice. The value of the 99mTc-PG cholescintigram lies in the confidence with which complete extrahepatic biliary obstruction can be diagnosed. The "scintigraphic Courvoisier's sign" seems a useful indicator of malignant obstruction.

Platelet ascorbic acid levels in normal subjects and in disease

The platelet ascorbic acid concentration was measured in 26 normal subjects and found to be 20 times as high as in plasma. This is in agreement with previous reports in the literature. The platelets of patients with uraemia, leukaemia, and megaloblastic anaemia had a lower than normal platelet ascorbic acid content. In uraemia and megaloblastic anaemia the plasma ascorbic acid concentration was normal suggesting that a platelet defect may be responsible for the low platelet ascorbic acid content. In leukaemia the low platelet ascorbic acid content is probably secondary to a low plasma level.

The diagnosis of pulmonary embolism: a review with particular reference to the use of radionuclides

Pulmonary embolism was first recognized as an important entity early in the nineteenth century. The evolution of our knowledge of this disorder has been reviewed with particular emphasis on the various diagnostic techniques which have been used to assist in its recognition. These have included physical examination to demonstrate the presence of classical physical signs, electrocardiography, biochemical tests, radiological examinations, pulmonary function tests, ultra-sound and methods employing radionuclides. The wide variety of techniques applied to this problem clearly indicates that no currently available test is entirely satisfactory alone. Probably the most significant advance in recent years has been the development of lung perfusion scanning which has provided at the very least a valuable screening test and a ready method of studying serially the natural history of the perfusion defects produced by thromboembolic disease.

New method for the estimation of platelet ascorbic acid

Present techniques for the estimation of platelet ascorbic acid allow interference by other substances in the sample. A new and more specific method of analysis is presented. The proposed method owes its increased specificity to resolution of the extract by thin-layer chromatography. By this means ascorbic acid is separated from other reducing substances present. The separated ascorbic acid is eluted from the thin layer and estimated by a new and very sensitive procedure: ascorbic acid is made to react with ferric chloride and the ferrous ions so formed are estimated spectrophotometrically by the coloured derivative which they form with tripyridyl-Striazine. Results obtained with normal blood platelets were consistently lower than simultaneous determinations by the dinitrophenylhydrazine (DNPH) method.