Blood withdrawal acutely impairs cardiac filling, output and aerobic capacity in proportion to induced hypovolemia in middle-aged and older women

Blood donation entails acute reductions of cardiorespiratory fitness in healthy men. Whether these effects can be extrapolated to blood donor populations comprising women remains uncertain. The purpose of this study was to comprehensively assess the acute impact of blood withdrawal on cardiac function, central hemodynamics and aerobic capacity in women throughout the mature adult lifespan. Transthoracic echocardiography and O2 uptake were assessed at rest and throughout incremental exercise (cycle ergometry) in healthy women (n = 30, age: 47–77 yr). Left ventricular end-diastolic volume (LVEDV), stroke volume (SV), cardiac output (Q̇) and peak O2 uptake (V̇O2peak), and blood volume (BV) were determined with established methods. Measurements were repeated following a 10% reduction of BV within a week period. Individuals were non-smokers, non-obese and moderately fit (V̇O2peak = 31.4 ± 7.3 mL·min–1·kg–1). Hematocrit and BV ranged from 38.0 to 44.8% and from 3.8 to 6.6 L, respectively. The standard 10% reduction in BV resulted in 0.5 ± 0.1 L withdrawal of blood, which did not alter hematocrit (P = 0.953). Blood withdrawal substantially reduced cardiac LVEDV and SV at rest as well as during incremental exercise (≥10% decrements, P ≤ 0.009). Peak Q̇ was proportionally decreased after blood withdrawal (P < 0.001). Blood withdrawal induced a 10% decrement in V̇O2peak (P < 0.001). In conclusion, blood withdrawal impairs cardiac filling, Q̇ and aerobic capacity in proportion to the magnitude of hypovolemia in healthy mature women. Novelty: The filling of the heart and therefore cardiac output are impaired by blood withdrawal in women. Oxygen delivery and aerobic capacity are reduced in proportion to blood withdrawal.

Evaluation of processes, outcomes, and use of midline peripheral catheters for the purpose of blood collection

HIGHLIGHTS Results added knowledge on use of midline catheters (MCs) for blood sampling. Using MCs for blood withdrawal resulted in low rates of hemolysis (0.69%). Dwell time was longer in those who had blood drawn from their MC. Nurse practices for blood sampling from MCs varied and learned from other nurses. Background: Blood withdrawal from midline catheters (MCs) is done clinically, but no studies were found evaluating outcomes from this procedure, nor were clinical guidelines found. Drawing blood samples from short peripheral catheters is associated with higher hemolysis rates. Methods: A prospective, observational, mixed methods study was used to evaluate outcomes from using MCs for blood withdrawal. Focus group sessions were held to evaluate nurses' practices for this procedure. Results: Data were collected over 3 months on 397 MCs in 378 patients. Hemolysis rates when the MC was used for blood withdrawal was 0.69% in 1021 tests. More than half had blood specimens drawn through the MC, and the time known for the successful withdrawal was on average 64 ± 85 hours. Mean dwell time for all MCs was 108.5 ± 98 hours, and when MCs were used for blood withdrawal, mean dwell time was 127.19 ± 109.13 hours and for MCs not used for blood withdrawal, 88.34 ± 79.86 hours (P < 0.001). In 338 patients who received therapy through their MC (n = 338), 87% completed intended therapy: 88% with blood withdrawal and 81% without blood withdrawal. Qualitative analysis from focus groups demonstrated wide variation in practice for blood sampling from MCs, and most learned techniques from their preceptors, other nurses, or patients. Conclusions: Findings indicated that blood withdrawal from one specific type of MC had low rates of hemolysis, increased dwell time, and completion of therapy. More studies are needed to determine best practices for blood sampling through various types of MCs and outcomes.

Evaluation of Processes, Outcomes, and Use of Midline Peripheral Catheters for the Purpose of Blood Collection

Highlights Results added knowledge on use of midline catheters (MCs) for blood sampling. Using MCs for blood withdrawal resulted in low rates of hemolysis (0.69%). Dwell time was longer in those who had blood drawn from their MC. Nurse practices for blood sampling from MCs varied and learned from other nurses.

Clotting functional stability of withdrawing blood in storage for acute normovolemic hemodilution: a pilot study

Purpose This study was conducted to time-course changes of clotting function of withdrawing blood for acute normovolemic hemodilution (ANH). Methods Twelve enrolled patients who underwent ANH from August, 2018 to January, 2019. Blood was withdrawn into blood collection pack and shaken at 60–80 rpm for 24 h in room temperature. Clot formation was evaluated using rotational thromboelastometry (ROTEM™) just after blood withdrawal (control) and 4, 8, 12 and 24 h after blood withdrawal. We compared with the control value and each value of extrinsically-activated test with tissue factor (EXTEM), intrinsically-activated test using ellagic acid (INTEM) and fibrin-based extrinsically activated test with tissue factor (FIBTEM). Results Maximum clot firmness (MCF) of FIBTEM did not change significantly. MCF of EXTEM was significantly decreased time-dependent manner but all MCF of EXTEM were within a normal range. Maximum percent change in MCF of EXTEM was 12.4% [95% confidence interval (CI): 9.0–15.8%]. The difference in the maximum clot elasticity (MCE) between EXTEM and FIBTEM (MCEEXTEM−MCEFIBTEM) was significantly decrease from 8 h after blood withdrawal. Maximum percent change in MCEEXTEM−MCEFIBTEM was 30.2% (95% CI:17.6–42.9%) at 24 h after blood withdrawal. Conclusion Even though the MCE significantly decreased in a time-dependent manner, MCF of FIBTEM and EXTEM was normal up to 24 h storage. The blood of ANH can use for the purpose of hemostasis at least 8 h stored at room temperature after blood withdrawal. Future studies are needed to elucidate the clinical impact on the patient after delayed transfusion of ANH blood with regard to patient’s hemostasis.

Unexpected abnormal coagulation test results in a 2-year-old child

Rejection of the sample with repeated blood withdrawal is always an unwanted consequence of sample nonconformity and preanalytical errors, especially in the most vulnerable population – children. Here is presented a case with unexpected abnormal coagulation test results in a 2-yearold child with no previously documented coagulation disorder. Child is planned for tympanostomy tubes removal under the anaesthesia driven procedure, and preoperative coagulation tests revealed prolonged prothrombin time, activated partial thromboplastin time and thrombin time, with fibrinogen and antithrombin within reference intervals. From the anamnestic and clinical data, congenital coagulation disorder was excluded, and with further investigation, sample mismatch, clot presence and accidental ingestion of oral anticoagulant, heparin contamination or vitamin K deficiency were excluded too. Due to suspected EDTA carryover during blood sampling another sample was taken the same day and all tests were performed again. The results for all tests were within reference intervals confirming EDTA effect on falsely prolongation of the coagulation times in the first sample. This case can serve as alert to avoid unnecessary loss in terms of blood withdrawal repetitions and discomfort of the patients and their relatives, tests repeating, prolonging medical procedures, and probably delaying diagnosis or proper medical treatment. It is the responsibility of the laboratory specialists to continuously educate laboratory staff and other phlebotomists on the correct blood collection as well as on its importance for the patient’s safety.

Investigating the relationship between melatonin levels, melatonin system, microbiota composition and bipolar disorder psychopathology across the different phases of the disease

Background Bipolar disorder (BD) is characterized by recurrent episodes of depression and mania/hypomania alternating with intervals of well-being. The neurobiological underpinnings of BD are still veiled although there is evidence pointing to a malfunction of the circadian clock system that is regulated by the neuromodulator melatonin (MLT). Small sample size studies in BD patients have shown that changes in the levels of MLT are associated with shifts in illness status. Moreover, mood stabilizers (including lithium and valproic acid) influence the MLT system. Of interest, MLT also modulates intestinal microbiota, and recent work suggests an important role of microbiota alterations in neuropsychiatric disorders, including BD. This study is designed to explore whether the possible patterns of associations between changes in the levels of MLT and its precursors and BD mood phases are modulated by variants within the genes encoding for the elements of the MLT system and/or by the microbiota composition. Methods We will conduct a 2-year follow-up study in 50 BD patients during the three different mood phases of the disease. For each phase, we will perform a blood withdrawal for the analysis of MLT levels and of variants of the genes related to the MLT pathway between 8 and 10 a.m. after an overnight fasting, a stool specimen collection for the analysis of microbiota composition, and a detailed psychometric assessment for depression, mania, impulsivity and cognitive abilities. We will also recruit 50 healthy age-matched controls in whom we will perform a blood withdrawal between 8 and 10 a.m. after an overnight fasting, a stool specimen collection, and a psychometric assessment to exclude the presence of psychiatric disorders. Discussion In this cross sectional (case–control vs. BD comparisons) and longitudinal (24 months) study, we expect to clarify the link between the MLT system, microbiota and BD psychopathology. We expect to identify some typical BD symptomatic clusters that will be more strictly associated with variations in the MLT system. In a personalized medicine perspective, this subgroup of BD patients may benefit from a pharmacological therapy targeting the MLT system. Trial registration This study protocol was approved by the Ethics Committee of the University Hospital Agency of Cagliari (PG/2019/6277)