A Standard Push-Pull Protocol for Waste-Free Sampling in the Pediatric Intensive Care Unit

Impact of Blood Sampling Methods on Blood Loss and Transfusion After Pediatric Cardiac Surgery: An Observational Study

OBJECTIVES

The aims of this study were to assess the impact of the closed-loop sampling method on blood loss and the need for blood transfusion in pediatric patients following cardiac surgery.

DESIGN

Retrospective observational study.

SETTING

A single tertiary center.

PARTICIPANTS

All pediatric patients younger than 4 years old who were admitted to the pediatric intensive care unit (PICU) after cardiac surgery were enrolled. The study included 100 pediatric patients in the conservative (postimplementation) group and 43 pediatric patients in the nonconservative group (preimplementation).

INTERVENTIONS

Observational.

MEASUREMENTS

The primary outcome was the volume of blood loss during the PICU follow-up period. The secondary outcomes were the requirement for blood transfusion in each group, duration of mechanical ventilation, length of intensive care unit (ICU) stay, length of hospital stay, and mortality.

MAIN RESULTS

In the conservative (postimplementation) group, blood loss during the follow-up period was 0.67 (0.33-1.16) mL/kg/d, while it was 0.95 (0.50-2.30) mL/kg/d in the nonconservative (preimplementation) group, demonstrating a significant reduction in blood loss in the conservative group (p = 0.012). The groups showed no significant differences in terms of the required blood transfusion volume postoperatively during the first 24 hours, first 48 hours, or after 48 hours (p = 0.061, 0.536, 0.442, respectively). The frequency of blood transfusion was comparable between the groups during the first 24 hours, first 48 hours, or after 48 hours postoperatively (p = 0.277, 0.639, 0.075, respectively). In addition, the groups did not show significant differences in the duration of mechanical ventilation, length of ICU stay, length of hospital stay, or mortality.

CONCLUSIONS

The closed-loop sampling method can be efficient in decreasing blood loss during postoperative PICU follow-up for pediatric patients after cardiac surgeries. However, its application did not reduce the frequency or the volume of blood transfusion in these patients.

Optimal volume for the draw-and-return methods to enhance activated partial thromboplastin time ratio accuracy in hemodialysis patients with central venous catheters

Background

Significant errors of activated partial thromboplastin time (aPTT) ratio were frequently observed in blood sampling from central venous dialysis catheter (CVC) of hemodialysis (HD) patients. Following the draw-and-return methods, initial blood withdrawal from the catheter before sampling can reduce the error, but the optimal withdrawal volume remains undetermined.

Aim

The objective of this study is to determine the optimal blood withdrawal volume for the draw-and-return methods to improve aPTT ratio accuracy in hemodialysis patients with CVC.

Methods

A prospective study was conducted in patients receiving HD via CVC. Four blood samples were collected from each patient, involving a peripheral venipuncture and three draw-and-return samples (10 ml, 20 ml and 25 ml groups). The aPTT ratio of a peripheral sample was used as a reference to determine the aPTT ratio accuracy for each draw-and-return group. Subsequently, the agreement was illustrated using modified Bland-Altman plot.

Results

A total of 1,000 samples were obtained from 250 patients. The patients had a mean age of 59.6 ± 15.4 years, with 17.2% using citrate as the CVC's locking agent. The adjusted accuracies of the aPTT ratio varied significantly among the three withdrawal volumes (p-value <0.001). The 25 ml group demonstrated the highest accuracy (43.2%; 95%CI, 38.0-48.4), followed by the 20 ml group (30.0%; 95%CI, 24.9-35.2), and the 10 ml group (18.0%; 95%CI, 12.8-23.2). Additionally, using citrate as a locking agent provided more than 80.0% aPTT ratio accuracy, whereas heparin demonstrated inferior accuracy even in the 25 ml withdrawal group.

Conclusion

The optimal blood withdraw volume for the draw-and-return methods concluded at 20 ml for citrate locked-CVC and 25 ml for heparin which significantly improved aPTT ratio accuracies. Applying citrate as a locking agent provides clear benefits for aPTT ratio monitoring, while peripheral venipuncture is recommended in cases of heparin-locked CVC.

A comparative study on coagulation and hematologic laboratory techniques for blood sampling using the push-pull method from a CVC versus venipuncture

OBJECTIVES

To demonstrate the equivalence and substitutability of two blood collection methods: the push-pull method from a CVC and direct venous puncture (DVP).

METHODS

A comparative, within-subject study was conducted between September 2021 and December 2021 at a hospital in NanTong city. The sample comprised critically ill patients aged 18 and older in critical care units such as general, emergent, cardiac, respiratory, and neurological units. A total of 154 paired blood samples were collected via a CVC and direct venous puncture. This study focused on the laboratory results of the coagulation and hematologic tests. The reproducibility and reliability of the results were calculated by the mean of the coefficient of variation (CV) and the intraclass correlation coefficient (ICC). Bland-Altman statistics were used to analyze the substitutability of the two blood collection methods.

RESULTS

The difference in the means between the two methods ranged from -1.61 to 0.09, and the coefficients of variation for both methods were similar. The ICCs of the two methods were all above 0.90, which indicated excellent reliability. In the Bland-Altman plots, all of the blood samples that obtained by the push-pull method were within clinically acceptable ranges compared to the samples obtained by direct venous puncture.

CONCLUSION

The push-pull method of collecting blood specimens from a CVC should be acceptable for coagulation and hematologic laboratory tests.

Strategies to Reduce Diagnostic Blood Loss and Anemia in Hospitalized Patients: A Scoping Review

OBJECTIVES

Blood sampling is a recognized contributor to hospital-acquired anemia. We aimed to bundle all published neonatal, pediatric, and adult data regarding clinical interventions to reduce diagnostic blood loss.

DATA SOURCES

Four electronic databases were searched for eligible studies from inception until May 2021.

STUDY SELECTION

Two reviewers independently selected studies, using predefined criteria.

DATA EXTRACTION

One author extracted data, including study design, population, period, intervention type and comparator, and outcome variables (diagnostic blood volume and frequency, anemia, and transfusion).

DATA SYNTHESIS

Of 16,132 articles identified, we included 39 trials; 12 (31%) were randomized controlled trials. Among six types of interventions, 27 (69%) studies were conducted in adult patients, six (15%) in children, and six (15%) in neonates. Overall results were heterogeneous. Most studies targeted a transfusion reduction ( n = 28; 72%), followed by reduced blood loss ( n = 24; 62%) and test frequency ( n = 15; 38%). Small volume blood tubes ( n = 7) and blood conservation devices ( n = 9) lead to a significant reduction of blood loss in adults (8/9) and less transfusion of adults (5/8) and neonates (1/1). Point-of-care testing ( n = 6) effectively reduced blood loss (4/4) and transfusion (4/6) in neonates and adults. Bundles including staff education and protocols reduced blood test frequency and volume in adults (7/7) and children (5/5).

CONCLUSIONS

Evidence on interventions to reduce diagnostic blood loss and associated complications is highly heterogeneous. Blood conservation devices and smaller tubes appear effective in adults, whereas point-of-care testing and bundled interventions including protocols and teaching seem promising in adults and children.

Avoidable Blood Loss in Critical Care and Patient Blood Management: Scoping Review of Diagnostic Blood Loss

Background: Anemia remains one of the most common comorbidities in intensive care patients worldwide. The cause of anemia is often multifactorial and triggered by underlying disease, comorbidities, and iatrogenic factors, such as diagnostic phlebotomies. As anemia is associated with a worse outcome, especially in intensive care patients, unnecessary iatrogenic blood loss must be avoided. Therefore, this scoping review addresses the amount of blood loss during routine phlebotomies in adult (>17 years) intensive care patients and whether there are factors that need to be improved in terms of patient blood management (PBM). Methods: A systematic search of the Medline Database via PubMed was conducted according to PRISMA guidelines. The reported daily blood volume for diagnostics and other relevant information from eligible studies were charted. Results: A total of 2167 studies were identified in our search, of which 38 studies met the inclusion criteria (9 interventional studies and 29 observational studies). The majority of the studies were conducted in the US (37%) and Canada (13%). An increasing interest to reduce iatrogenic blood loss has been observed since 2015. Phlebotomized blood volume per patient per day was up to 377 mL. All interventional trials showed that the use of pediatric-sized blood collection tubes can significantly reduce the daily amount of blood drawn. Conclusion: Iatrogenic blood loss for diagnostic purposes contributes significantly to the development and exacerbation of hospital-acquired anemia. Therefore, a comprehensive PBM in intensive care is urgently needed to reduce avoidable blood loss, including blood-sparing techniques, regular advanced training, and small-volume blood collection tubes.