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ObjectiveTo evaluate whether a standard operating procedure (SOP) for canine packed cell volume (PCV) measurement reduces operator-dependent variation and improves accuracy within a veterinary teaching hospital environment.Materials and methodsClinical staff and final-year undergraduate veterinary students were recruited to perform PCV measurements in blinded duplicate samples. Participants were randomly allocated to perform this with or without an SOP. Participants’ results were compared against a reference, generated by the authors following the World Health Organization guidelines.ResultsThe study population comprised 18 clinical staff and 39 students. Three clinical staff and seven students displayed errors consistent with inaccurate reading, only one of whom had access to the SOP. Five students and two clinical staff had errors attributable to incorrect preparation, with only one having access to the SOP. Interoperator variation was significantly less using the SOP. Using the SOP, 95 per cent of the results were within 0.0125 l/l of the reference value, in comparison with within 0.09 l/l without SOP. Interoperator variation was significantly less in the SOP group (P=0.0025).Clinical significanceUsing the SOP resulted in less variation and more accurate results. This confirms that PCV measurement with an SOP can truly be a ‘waived’ test.

Abstract Introduction/Objective Red cell exchange (RCE) is utilized as a therapeutic or prophylactic procedure for patients with sickle cell disease (SCD). When performing RCE, three hematocrits (Hct) are taken into account: pre-procedure and goal Hct for the patient and average Hct (avg-Hct) of the transfused RBC units. Although there is no definitive community consensus, many transfusion services employ RBC unit avg-Hct of 55% per available guidance. Our center anecdotally observed that utilizing RBC unit avg-Hct of 55% often resulted in post-procedure patient Hcts higher than intended goal Hct, potentially causing hyperviscosity. This study aims to examine the effect of changing the avg-Hct from 55% to 60% on the accuracy of post-procedure HCTs, with the 60% avg-Hct employed based on prior quality studies of RBC units at our facility. Methods/Case Report We performed a retrospective chart review for SCD patients receiving chronic, prophylactic RCE at a large academic hospital, collecting the following for each procedure: goal procedure Hct, number of RBC units exchanged, avg-Hct used, and pre-/post-procedure patient Hcts. Differences between goal Hcts and post- procedure Hcts for each procedure in the avg-Hct=55% and avg-Hct=60% groups were calculated. Next, mean calculated differences for both groups were compared using a two-sample t-test (P<0.05 was considered significant). Results (if a Case Study enter NA) From 1/2023–2/2024, 293 prophylactic RCEs were performed for SCD patients. Median number of RBC units per procedure was 7, with 51% of procedures (n=149) employing unit avg-Hct=55%, while 49% of procedures (n=144) used a unit avg-Hct=60%. Post-procedure patient Hct and goal Hct differences were statistically different according to unit avg-Hct values utilized (mean difference=1.31% for avg-Hct=55% vs mean difference=0.52% for avg-Hct=60%; P<0.0001). Conclusion Changing our protocol to use RBC unit avg-Hct=60% resulted in post-procedure patient Hcts significantly closer to intended goals. Utilization of a more accurate average-Hct value has a substantial impact on post-procedure Hct in RCEs and may limit adverse events.

Chronic mountain sickness is a maladaptive syndrome that affects individuals living permanently at high altitude and is characterized primarily by excessive erythrocytosis (EE). Recent results concerning the impact of EE in Andean highlanders on clotting and the possible promotion of hypercoagulability, which can lead to thrombosis, were contradictory. We assessed the coagulation profiles of Andeans highlanders with and without excessive erythrocytosis (EE+ and EE−). Blood samples were collected from 30 EE+ and 15 EE− in La Rinconada (Peru, 5100–5300 m a.s.l.), with special attention given to the sampling pre‐analytical variables. Rotational thromboelastometry tests were performed at both native and normalized (40%) haematocrit using autologous platelet‐poor plasma. Thrombin generation, dosages of clotting factors and inhibitors were measured in plasma samples. Data were compared between groups and with measurements performed at native haematocrit in 10 lowlanders (LL) at sea level. At native haematocrit, in all rotational thromboelastometry assays, EE+ exhibited hypocoagulable profiles (prolonged clotting time and weaker clot strength) compared with EE− and LL (all P < 0.01). At normalized haematocrit, clotting times were normalized in most individuals. Conversely, maximal clot firmness was normalized only in FIBTEM and not in EXTEM/INTEM assays, suggesting abnormal platelet activity. Thrombin generation, levels of plasma clotting factors and inhibitors, and standard coagulation assays were mostly normal in all groups. No highlanders reported a history of venous thromboembolism based on the dedicated survey. Collectively, these results indicate that EE+ do not present a hypercoagulable profile potentially favouring thrombosis. What is the central question of this study? Are Andean highlanders with excessive erythrocytosis (EE+) exhibiting a hypercoagulable profile compared with highlanders without erythrocytosis (EE−) and lowlanders (LL)? What is the main finding and its importance? Despite normal plasma coagulation (thrombinography and levels of clotting factors and inhibitors), EE+ exhibited a hypocoagulable rotational thromboelastometry profile (prolonged clotting time and weaker clot strength) compared with EE− and LL. In EE+, haematocrit normalization at 40% corrected maximal clot firmness in rotational thromboelastometry FIBTEM tests, but not in EXTEM and INTEM tests, suggesting that platelets play a role in the native hypocoagulable profile.

The definition for anemia in pregnancy is outdated, derived from Scandinavian studies in the 1970's to 1980's. To identity women at risk of blood transfusion, a common cause of Severe Maternal Morbidity, a standard definition of anemia in pregnancy in a modern, healthy United States cohort is needed. To define anemia in pregnancy in a United States population including a large county vs. private hospital population using uncomplicated patients. Inclusion criteria were healthy women with the first prenatal visit before 20 weeks. Exclusion criteria included preterm birth, preeclampsia, hypertension, diabetes, short interval pregnancy (<18 months), multiple gestation, abruption, and fetal demise. All women had iron fortification (Ferrous sulfate 325 mg daily) recommended. The presentation to care and pre-delivery hematocrits were obtained, and the percentiles determined. A total of 2000 patients were included, 1000 from the public county hospital and 1000 from the private hospital. Each cohort had 250 patients in each 2011, 2013, 2015, and 2018. The cohorts were compared for differences in the fifth percentile for each antepartum epoch. Student's t-test and chi-squared statistical tests were used for analysis, p-value of ≤0.05 was considered significant. In the public and private populations, 777 and 785 women presented in the first trimester while 223 and 215 presented in the second. The women at the private hospital were more likely to be older, Caucasian race, nulliparous, and present earlier to care. The fifth percentile was compared between the women in the private and public hospitals and were clinically indistinguishable. When combining the cohorts, the fifth percentile for hemoglobin/hematocrit was 11 g/dL/32.8% in the first trimester, 10.3 g/dL/30.6% in the second trimester, and 10.0 g/dL/30.2% pre-delivery. Fifth percentile determinations were made from a combined cohort of normal, uncomplicated pregnancies to define anemia in pregnancy. Comparison of two different cohorts confirms that the same definition for anemia is appropriate regardless of demographics or patient mix.

Background The lactate-to-hematocrit ratio (LHR) is strongly associated with the prognosis of patients critically ill with various diseases. However, the relationship between LHR and the prognosis of critically ill patients with cirrhosis and sepsis has not been explored. Therefore, this study examined the association between the LHR and short- and long-term prognoses in this special group of patients. Methods Hospitalization data of patients with cirrhosis and sepsis in an intensive care unit between 2008 and 2022 were retrospectively analyzed. The LHR was calculated from arterial blood lactate and hematocrit levels obtained during the first measurement within 24 h of admission. The threshold for optimal LHR was determined using standard statistical tools in R. The risks of death were compared between patients with LHR values above and below this threshold. Multivariate Cox proportional hazards regression models were used to examine the association between LHR and the short- and long-term mortality risks in this group of patients. The potential dose-response relationship between LHR and mortality were investigated. Additionally, the predictive ability, sensitivity, and specificity of LHR for the risk of all-cause mortality were evaluated. Finally, subgroup analyses were performed to assess the relationship between LHR and prognosis in different populations. Results Among the 1881 patients included in this study, the threshold LHR was 0.12. Kaplan–Meier analysis showed that patients with higher LHR had significantly higher risks of intensive care unit (ICU); in-hospital; and 14-, 28-, and 90-day mortality (all log-rank P  < 0.001). The multivariate Cox proportional hazards models suggested an independent association between high LHR and 14-, 28-, and 90-day all-cause mortalities. RCS analyses showed a nonlinear association between LHR and short- and long-term all-cause mortality in patients with cirrhosis and sepsis. ROC curve analyses showed that LHR had a better predictive ability for prognosis in patients with cirrhosis combined with sepsis than other indicators. Subgroup analysis showed no significant interaction between LHR and most of the subgroups. Conclusion High LHR values were strongly associated with poor short- and long-term prognoses in critically ill patients with cirrhosis and sepsis.

Oxygen heterogeneity in solid tumors is recognized as a limiting factor for therapeutic efficacy. This heterogeneity arises from the abnormal vascular structure of the tumor, but the precise mechanisms linking abnormal structure and compromised oxygen transport are only partially understood. In this paper, we investigate the role that red blood cell (RBC) transport plays in establishing oxygen heterogeneity in tumor tissue. We focus on heterogeneity driven by network effects, which are challenging to observe experimentally due to the reduced fields of view typically considered. Motivated by our findings of abnormal vascular patterns linked to deviations from current RBC transport theory, we calculated average vessel lengths L̄ and diameters d from tumor allografts of three cancer cell lines and observed a substantial reduction in the ratio λ = L̄/d̄ compared to physiological conditions. Mathematical modeling reveals that small values of the ratio λ (i.e.,λ < 6) can bias hematocrit distribution in tumor vascular networks and drive heterogeneous oxygenation of tumor tissue. Finally, we show an increase in the value of λ in tumor vascular networks following treatment with the antiangiogenic cancer agent DC101. Based on our findings, we propose λ as an effective way of monitoring the efficacy of antiangiogenic agents and as a proxy measure of perfusion and oxygenation in tumor tissue undergoing antiangiogenic treatment.

In human medical practice, a hematological rule of three has been validated for healthy human populations. One such formula is estimating hemoglobin (Hb) levels as 1/3 rd of Packed Cell Volume (PCV). However, no such hematological formulae have been devised and validated for veterinary medical practice. The present study was devised with an aim to evaluate the relationship between hemoglobin (Hb) concentration and Packed Cell Volume (PCV) in camels (n = 215) being reared under pastoralism, and to devise a simple pen-side hematological formula for estimation of Hb from PCV. The PCV was determined through microhematocrit method whereas Hb estimation by cyanmethaemoglobin method (HbD). The Hb was also calculated as 1/3 rd of PCV and was dubbed as calculated Hb (HbC). Overall HbD and HbC were significantly (P≥0.05) different. Similar results were attained for all study groups i . e . males (n = 94) and females (n = 121), and young (n = 85) and adult (n = 130) camels. The corrected Hb (CHb) was deduced through regression prediction equation attained from linear regression model. Scatterplots were drawn, linear regression was carried out, and Bland Altman chart was built for agreement of both methods of Hb estimation. A non-significant (P≥0.05) difference was noticed between HbD and CHb. Bland Altman agreement analysis revealed satisfactory agreement between HbD and CHb and the data was distributed closely around the mean difference line (Mean = 0.1436, 95% CI = 3.00, -2.72). A simplified pen-side hematological formula for deducing Hb concentration from PCV is accordingly recommended viz . Hb concentration (g/dL) = 0.18(PCV)+5.4 for all age and gender groups of camels instead of its calculation as one-third of PCV.

We evaluated validity, reliability, and effect of user expertise of “HaemoCalc”, a mobile phone application for hematocrit (Hct) measurement from fingerpick blood samples, compared to a traditional Hawksley microhaematocrit reader (MHR). Experiment 1 examined the effect pitch angle during image capture exerted on the validity of Hct values. Twenty participants' samples were analyzed at 0°, 10°, and 20° directly over the sample, and 33° with a 10 cm setback. Analysis of variance (ANOVA) revealed a significant effect of angle on Hct values (p < 0.01). Measurements at 33° pitch differed from other angles and the MHR (p < 0.001, d = 2.31–3.06). Bland–Altman analysis showed good agreement at 0°, 10°, and 20° (mean differences: −0.4% to 1.0%) but poor agreement at 33° (mean difference: −4.4%, LOA: −0.7% to 8.4%). Experiment 2 assessed inter‐ and intra‐rater reliability of expert and novice users (n = 12). Participants performed three trials each. HaemoCalc and MHR showed excellent reliability (ICC = 0.95–1.00). No differences were observed between experts and novices (p = 1.000, d = 0.01–0.39). HaemoCalc is a valid and reliable tool for Hct measurement at small pitch angles and in expert and novice users. The HaemoCalc app offers scalability, repeatability, health and safety benefits, and potential applications in medical education and remote learning.

The monthly Extended Reconstructed Sea Surface Temperature (ERSST) dataset, available on global 2° × 2° grids, has been revised herein to version 4 (v4) from v3b. Major revisions include updated and substantially more complete input data from the International Comprehensive Ocean–Atmosphere Data Set (ICOADS) release 2.5; revised empirical orthogonal teleconnections (EOTs) and EOT acceptance criterion; updated sea surface temperature (SST) quality control procedures; revised SST anomaly (SSTA) evaluation methods; updated bias adjustments of ship SSTs using the Hadley Centre Nighttime Marine Air Temperature dataset version 2 (HadNMAT2); and buoy SST bias adjustment not previously made in v3b. Tests show that the impacts of the revisions to ship SST bias adjustment in ERSST.v4 are dominant among all revisions and updates. The effect is to make SST 0.1°–0.2°C cooler north of 30°S but 0.1°–0.2°C warmer south of 30°S in ERSST.v4 than in ERSST.v3b before 1940. In comparison with the Met Office SST product [the Hadley Centre Sea Surface Temperature dataset, version 3 (HadSST3)], the ship SST bias adjustment in ERSST.v4 is 0.1°–0.2°C cooler in the tropics but 0.1°–0.2°C warmer in the midlatitude oceans both before 1940 and from 1945 to 1970. Comparisons highlight differences in long-term SST trends and SSTA variations at decadal time scales among ERSST.v4, ERSST.v3b, HadSST3, and Centennial Observation-Based Estimates of SST version 2 (COBE-SST2), which is largely associated with the difference of bias adjustments in these SST products. The tests also show that, when compared with v3b, SSTAs in ERSST.v4 can substantially better represent the El Niño/La Niña behavior when observations are sparse before 1940. Comparisons indicate that SSTs in ERSST.v4 are as close to satellite-based observations as other similar SST analyses.