What blood conservation practices are effective at reducing blood sampling volumes and other clinical sequelae in intensive care? A systematic review

OBJECTIVES

The objective of this study was to critically appraise and synthesise evidence for blood conservation strategies in intensive care. Blood sampling is a critical aspect of intensive care to guide clinical decision-making. Repeated blood sampling can result in blood waste and contamination, leading to iatrogenic anaemia and systemic infection.

REVIEW METHOD USED

Cochrane systematic review methods were used including meta-analysis, and independent reviewers.

DATA SOURCES

A systematic search was conducted in Medline, CINAHL, PUBMED and EMBASE databases. The search was limited to randomised controlled trials (RCTs) and cluster RCTs, published in English between 2000 and 2021.

REVIEW METHODS

Paired authors independently assessed database search results and identified eligible studies. Trials comparing any blood conservation practice or product in intensive care were included. Primary outcomes were blood sample volumes and haemoglobin change. Secondary outcomes included proportion of patients receiving transfusions and infection outcomes. Quality appraisal employed the Cochrane Risk of Bias tool. Meta-analysis using random effects approach and narrative synthesis summarised findings.

RESULTS

Eight studies (n = 1027 patients), all RCTs were eligible. Six studies included adults, one studied paediatrics and one studied preterm infants. Seven studies evaluated a closed loop blood sampling system, and one studied a conservative phlebotomy protocol. Studies were of low to moderate quality. Meta-analysis was not possible for interventions targeting blood sample volumes or haemoglobin. Decreased blood sample volumes reported in four studies were attributable to a closed loop system or conservative phlebotomy. No study reported a significant change in haemoglobin. Meta-analysis demonstrated that use of a closed system (compared to open system) reduced the proportion of patients receiving transfusion [Risk Ratio (RR) 0.65, 95% CI 0.46-0.92; 287 patients] and reduced intraluminal fluid colonisation [RR 0.25, 95% CI 0.07-0.58; 500 patients].

CONCLUSIONS

Limited evidence demonstrates closed loop blood sampling systems reduced transfusion use and fluid colonisation. Simultaneous effectiveness-implementation evaluation of these systems and blood conservation strategies is urgently required.

PROSPERO PROTOCOL REGISTRATION REFERENCE

CRD42019137227.

Contamination of Blood Cultures From Arterial Catheters and Peripheral Venipuncture in Critically Ill Patients: A Prospective Multicenter Diagnostic Study

BACKGROUND

Collecting blood cultures from indwelling arterial catheters is an attractive option in critically ill adult patients when peripheral venipuncture is difficult. However, whether the contamination proportion of blood cultures from arterial catheters is acceptable compared with that from venipuncture is inconclusive.

RESEARCH QUESTION

Is contamination of blood cultures from arterial catheters noninferior to that from venipuncture in critically ill adult patients with suspected bloodstream infection?

STUDY DESIGN AND METHODS

In this multicenter prospective diagnostic study conducted at five hospitals, we enrolled episodes of paired blood culture collection, each set consisting of blood drawn from an arterial catheter and another by venipuncture, were obtained from critically ill adult patients with cilinical indication. The primary measure was the proportion of contamination, defined as the number of false-positive results relative to the total number of procedures done. The reference standard for true bloodstream infection was blinded assessment by infectious disease specialists. We examined the noninferiority hypothesis that the contamination proportion of blood cultures from arterial catheters did not exceed that from venipuncture by 2.0%.

RESULTS

Of 1,655 episodes of blood culture from December 2018 to July 2021, 590 paired blood culture episodes were enrolled, and 41 of the 590 episodes (6.9%) produced a true bloodstream infection. In blood cultures from arterial catheters, 33 of 590 (6.0%) were positive, and two of 590 (0.3%) were contaminated; in venipuncture, 36 of 590 (6.1%) were positive, and four of 590 (0.7%) were contaminated. The estimated difference in contamination proportion (arterial catheter - venipuncture) was -0.3% (upper limit of one-sided 95% CI, +0.3%). The upper limit of the 95% CI did not exceed the predefined margin of +2.0%, establishing noninferiority (P for noninferiority < .001).

INTERPRETATION

Obtaining blood cultures from arterial catheters is an acceptable alternative to venipuncture in critically ill patients.

CLINICAL TRIAL REGISTRATION

University Hospital Medical Information Network Center (UMIN-CTR); No.: UMIN000035392; URL: https://center6.umin.ac.jp/.

Closed arterial lab sampling devices: a study of compliance and best practice

As the quality of patient care continues to improve, nursing professionals are continuously tasked with researching, implementing, and evaluating best practices. The practice of obtaining blood samples from paediatric patients, using a conventional three-way stopcock method, has been associated with peripheral arterial catheter intraluminal contamination and catheter-related bloodstream infections. A paediatric cardiac intensive care unit (PCICU), in a large medical centre in the USA, set an objective to mitigate the risk of possible contamination by implementing the use of closed arterial lab sampling devices. The project extensively reviewed comparative literature of studies between conventional three-way stopcock methods and closed arterial lab sampling devices. Furthermore, it successfully implemented the recommended best practice with sustained compliance. This article discusses appraising current literature, translating into practice, and evaluating compliance throughout the PCICU over a 2-year period.

Influence of the marvelous™ three-way stopcock on the natural frequency and damping coefficient in blood pressure transducer kits

Two types of Planecta™ ports are commonly used as sampling ports in blood pressure transducer kits: a flat-type port (FTP) and a port with a three-way stopcock (PTS). Recently, a new type of three-way stopcock (Marvelous™) has been released as a Planecta™ counterpart, but its effects on the frequency characteristics and reliability of blood pressure monitoring have not been investigated. We assessed the influence of the Marvelous™ stopcock on the frequency characteristics of the pressure transducer kit. The basic pressure transducer kit, DT4812J, was modified by replacing one or two of the original three-way stopcocks with Marvelous™ stopcocks. The frequency characteristics (i.e., natural frequency and damping coefficient) of each kit were determined using wave parameter analysis software, and subsequently evaluated on a Gardner chart. Replacement of the original blood pressure transducer kit stopcocks with Marvelous™ stopcocks decreased the natural frequency (48.3 Hz) to 46.3 Hz or 44.8 Hz, respectively; the damping coefficient was not significantly changed. Plotting the data on a Gardner chart revealed that the changes fell within the adequate dynamic response region, indicating they were within the allowable range. Insertion of Marvelous™ stopcocks slightly affects the natural frequency of the pressure transducer kit, similar to inserting a PTS. The results indicate that the Marvelous™ stopcock is useful for accurate monitoring of arterial blood pressure, and may be recommended when insertion of two or more closed-loop blood sampling systems is necessary.

Closed blood conservation device for reducing catheter-related infections in children after cardiac surgery

BACKGROUND

Arterial catheters are potential sources of nosocomial infection.

OBJECTIVE

To investigate use of a closed blood conservation device in preventing catheter-related bloodstream infections in children after cardiac surgery.

METHODS

Children with an indwelling arterial catheter after cardiac surgery were randomly assigned to 2 groups: a control group with a conventional 3-way stopcock in the catheter system and an interventional group with the conservation device in the catheter system. Catheter tips, catheter intraluminal fluid, and blood samples obtained from the catheter and peripherally were cultured for microbiological analysis. RESULTS Intraluminal fluid contamination was significantly lower (P = .03) in the interventional group (3 of 147 catheters) than in the control group (10 of 137 catheters). The 2 groups did not differ significantly in the rate of tip colonization (9 of 147 vs 12 of 137; P = .40) or in the number of catheter-related bloodstream infections (0 of 147 vs 2 of 137; P = .21).

CONCLUSION

Use of a closed blood conservation device could decrease the incidence of catheter-related contamination of intraluminal fluid.

Frequency characteristics of pressure transducer kits with inserted pressure-resistant extension tubes

The accurate monitoring of arterial blood pressure is important for cardiovascular management. However, the frequency characteristics of pressure transducer kits are influenced by the length of the pressure-resistant tube. To date, there have been few studies addressing the frequency characteristics of pressure transducer kits with inserted pressure-resistant extension tubes (pressure-resistant extension tube (ET) circuits). In this study, we examine ET circuits from the viewpoint of the frequency characteristics of pressure transducer kits. DT4812J transducer kits (length 150 cm; Argon Medical Devices, TX, USA) were used. Three original ET circuits were prepared, with the pressure-resistant tube of the DT4812J being extended with a 30-cm length of pressure-resistant tube (180ET circuit), a 60-cm length of pressure-resistant tube (210ET circuit), and a 90-cm length of pressure-resistant tube (240ET circuit). Each of these circuits was evaluated as part of this study. The natural frequency of the original DT4812J circuit was 45.90 Hz while the damping coefficient was 0.160. For the 180 ET circuit, the natural frequency and damping coefficient were 36.4 Hz and 0.162, respectively. For the ET210 circuit, the natural frequency and damping coefficient were 30.3 Hz and 0.175, respectively. For the ET210 circuit, the natural frequency and damping coefficient were 25.3 Hz and 0.180, respectively. As a result of extending the circuit, it was found that the natural frequency decreased drastically, while the damping coefficient increased slightly. When the extension of a pressure transducer kit is required, we should pay careful attention to the major decrease in the natural frequency, which may influence the pressure monitoring.

Effect of using a Planecta™ port with a three-way stopcock on the natural frequency of blood pressure transducer kits

Blood pressure transducer kits are equipped with two types of Planecta™ ports-the flat-type Planecta™ port (FTP) and the Planecta™ port with a three-way stopcock (PTS). We reported that FTP application decreased the natural frequency of the kits. However, Planecta™ is an invaluable tool as it prevents infection, ensures technical simplicity, and excludes air. Hence, an ideal Planecta™ port that does not decrease the frequency characteristics is required. As a first step in this direction, we aimed to assess the influence of PTSs on the natural frequency of blood transducer kits. A DTXplus transducer kit (DT4812J; Argon Medical Devices, TX, USA) was used along with ≥1 PTSs (JMS, Hiroshima, Japan), and the frequency characteristics were assessed. The natural frequency and damping coefficient of each kit were obtained by using frequency characteristics analysis software, and these parameters were evaluated by plotting them on Gardner's chart. Regardless of whether one or two PTSs were inserted, the natural frequency of the kits only slightly decreased (from 42.5 to 41.1 Hz, when 2 PTSs were used). Thus, the frequency characteristics of the kits with PTSs were adequate for pressure monitoring. The insertion of ≥2 FTPs in pressure transducer kits should be avoided, as they markedly decrease the natural frequency and lead to underdamping. However, the effect of PTS insertion in pressure transducer kits on the frequency characteristics is minimal. Thus, we found that the use of PTS markedly improved the frequency characteristics as compared to the use of FTP.

Guideline for Prevention of Intravascular-Device–Related Infections

The “Guideline for Prevention of Intravascular Device-Related Infections” is designed to reduce the incidence of intravascular device-related infections by providing an over view of the evidence for recommendations considered prudent by consensus of Hospital Infection Control Practices Advisor y Committee (HICPAC) members. This two-part document updates and replaces the previously published Centers for Disease Control's (CDC) Guideline for Intravascular Infections (Am J Infect Control1983;11:183-199). Part I, “Intravascular Device-Related Infections: An Over view” discusses many of the issues and controversies in intravascular-device use and maintenance. These issues include definitions and diagnosis of catheter-related infection, appropriate barrier precautions during catheter insertion, inter vals for replacement of catheters, intravenous (IV) fluids and administration sets, catheter-site care, the role of specialized IV personnel, and the use of prophylactic antimi-crobials, flush solutions, and anticoagulants. Part II, “Recommendations for Prevention of Intravascular Device-Related Infections” provides consensus recommendations of the HICPAC for the prevention and control of intravascular device-related infections. A working draft of this document also was reviewed by experts in hospital infection control, internal medicine, pediatrics, and intravenous therapy. However, all recommendations contained in the guideline may not reflect the opinion of all reviewers.

Effect of planecta and ROSE™ on the frequency characteristics of blood pressure-transducer kits

Pressure-transducer kits have frequency characteristics such as natural frequency and damping coefficient, which affect the monitoring accuracy. The aim of the present study was to investigate the effect of planecta ports and a damping device (ROSE™, Argon Medical Devices, TX, USA) on the frequency characteristics of pressure-transducer kits. The FloTrac sensor kit (Edwards Lifesciences, CA, USA) and the DTXplus transducer kit (Argon Medical Devices) were prepared with planecta ports, and their frequency characteristics were tested with or without ROSE™. The natural frequency and damping coefficient of each kit were obtained using frequency characteristics analysis software and evaluated by plotting them on the Gardner's chart. By inserting a planecta port, the natural frequency markedly decreased in both the FloTrac sensor kit (from 40 to 22 Hz) and the DTXplus transducer kit (from 35 to 22 Hz). In both kits with one planecta port, the damping coefficient markedly increased by insertion of ROSE™ from 0.2 to 0.5, optimising frequency characteristics. In both kits with two planecta ports, however, the natural frequency decreased from 22 to 12 Hz. The damping coefficient increased from 0.2 to 0.8 by insertion of ROSE™; however, optimisation was not achieved even by ROSE™ insertion. Planecta ports decrease the natural frequency of the kit. ROSE™ is useful to optimise the frequency characteristics in the kits without or with one planecta port. However, optimisation is difficult with two or more planecta ports, even with the ROSE™ device.

Arterial catheters: indications, insertion and use in critical care

This article provides an overview of arterial catheters and their use within critical care. The indications for arterial catheterization are presented and the insertion techniques are discussed. The nursing care of patients with an arterial catheter is explained, with a focus on safety, haemodynamic monitoring and arterial blood sampling. The procedure for removal of an arterial catheter is described in a step-by-step guide. Post-procedure care and complications are also discussed and evidence-based strategies for the prevention of complications are suggested.

Reducing the costs of surgical correction of congenitally malformed hearts in developing countries

A large number of patients in developing countries require surgical correction of congenitally malformed hearts. Unfortunately, only a limited number of centres offer these patients surgery at an affordable cost. In this review, we discuss the problems in managing these patients, with an emphasis on reduction of costs, so that the maximum number of patients can benefit. It is apparent that containing costs requires a multipronged approach, which begins with timely referral, and continues with early surgical correction and adequate postoperative care carried out in a scientific manner. Indigenization, innovation, training of manpower, and building a team, are essential to cut the costs, and to improve the quality of care.

Blood Conservation Strategies in Cardiovascular Surgery

Blood conservation is a measurable intervention in which clinical and financial outcomes may be tracked. This article describes a systems approach to blood conservation for a cardiac surgery population. Four key areas are discussed: needs assessment, committee construction, blood conservation strategies, and outcome measurement. Specific evidenced-based blood conservation strategies include, but are not limited to, transfusion risk index, phlebotomy techniques, management of hemostasis and hemoglobin levels which includes blood testing, pharmacologic agents, and blood transfusion prescription guidelines.

The use of a blood conservation pressure transducer system in critically ill patients

We tried to determine if a blood conservation pressure transducer system reduced blood transfusions, increased haemoglobin concentration or reduced line infections in critically ill patients. One hundred patients were randomly allocated to conventional or blood conserving systems attached to systemic and pulmonary arterial catheters. Intravascular lines were cultured after removal. There were no significant differences in transfusions or haemoglobin concentration. Blood conservation: median units transfused, 2 (range 0-19); mean haemoglobin at 7 days, 11.2 g.dl-1 (SD, 1.0). Conventional: median units, 2 (range 0-34); mean haemoglobin at 7 days, 11.1 g.dl-1 (SD 1.0). Thirty-seven of 99 arterial lines were colonised in the controls compared with 29 of 96 in the blood conservation group. Patients who required haemofiltration in both groups had significantly increased transfusion requirements. Haemofiltration: median 6 units (range 0-34) vs. non-haemofiltered: median 1 (range 0-14; p < 0.001). There were no significant differences in transfusions, haemoglobin concentration or line colonisation with the blood conservation system. There is considerable potential for blood conservation during haemofiltration.

Microbiological evaluation of central venous catheter administration hubs

We compared, in three intensive care units, colonization of hubs with hub protection boxes or hubs with needleless closed connectors; 137 central venous catheters and 451 hubs were randomized in two groups with similar characteristics. Catheter and hub colonization were not different between the two groups. Among 30 colonized catheters, the same isolate was found in only two hubs; hub contamination rarely is responsible for catheter colonization in short-term catheters. Further studies are required to evaluate the benefit of protected hubs compared with unprotected hubs.

A written guideline implementation can lead to reductions in laboratory testing in an intensive care unit

The impact of developing guidelines for laboratory testing in an Intensive Care Unit (ICU) was examined. Targeted blood tests were recorded on fifty cardiac surgery and fifty general intensive care patients retrospectively. Following the introduction of guidelines, the study was repeated with prospective data collection. Comparison of the samples before and after the intervention showed a 25.9% reduction in all blood tests and a 17.1% reduction in arterial blood gases in the post cardiac surgery group. In general ICU patients, the drop in all tests was 16.6% and in arterial blood gases 21.9%. The cost saving from the cardiac surgery sample was N.Z.$3,637 and general ICU N.Z.$3,166, giving a sum total of N.Z.$6,803 in 100 patients. The potential cost savings for the annual admissions of 1,200 patients is N.Z.$81,636. This study shows that written guidelines can bring about major cost reduction in the short-term.

Evaluation of an on-demand, ex vivo bedside blood gas monitor on pulmonary artery blood gas determinations

Critically ill patients often have cardiopulmonary perturbations that require rapid and frequent assessment for optimal care, including cardiac output determinations, measurement of cardiac filling pressures, and arterial and mixed venous blood gas determinations. We evaluated the performance of a rapid, on-demand bedside blood gas monitor to determine arterial and mixed venous blood gas values. The blood gas monitor uses fluorescent optode technology to directly measure Po2, Pco2, and pH. This measurement is accomplished by aspirating blood from the artery or vein into a sampling chamber where it interfaces with the fluorescent optode. After approximately 90 s of equilibration, the blood gas values are reported. Since the blood is drawn into the sampling chamber, it can be returned to the patient, thus eliminating the need for phlebotomy. We studied 15 critically ill patients requiring systemic and pulmonary arterial catheterization. Conventional blood gas analysis was performed simultaneously. The results obtained from the blood gas monitor were compared with those obtained via traditional blood gas analysis using Bland-Altman plots and examination of bias and precision. The results were well within the expected clinical variance. During the study period, there was no interference with patient care or adverse events related to the use of the monitoring system. In conclusion, the blood gas monitor can provide rapid, accurate determinations of arterial and mixed venous blood gases allowing optimal therapeutic interventions in critically ill patients.

Microbial contamination of blood conservation devices during routine use in the critical care setting: results of a prospective, randomized trial

OBJECTIVES

To compare microbial contamination of two different blood conservation devices; to determine if there was an association between contamination of the blood conservation devices and clinical infections; to determine if there was a significant user preference for either of the two devices.

DESIGN

Prospective, randomized trial.

SETTING

Medical, neurosurgical, and spinal cord intensive care units of an urban, university hospital.

PATIENTS

Forty patients who required clinically indicated intrafierial catheters placed at new sites.

INTERVENTIONS

The two most widely available blood conservation devices at the time of the study (Venous Arterial blood Management Protection system [VAMP], Baxter Edwards Critical-Care, Irvine, CA; and Safe Draw, Ohmeda, Madison, WI) were chosen for comparison. After the normal 48 to 72 hrs of device use, the blood conservation systems were removed and semi-quantitative and quantitative cultures were taken from comparable sites of the two devices. Positive cultures from the patients were recorded and correlated with cultures obtained from the devices. In order to assess preference for either device, a survey tool was administered to the nursing staff who participated in the study.

MEASUREMENTS AND MAIN RESULTS

Quantitative cultures from all sites cultured in both groups demonstrated mean colony counts of < 10(3) colony-forming units (cfu)/mL. There were no statistically significant differences in the colony counts at any of the sites compared between the two groups. There were no statistically significant relationships between positive cultures and patient age, gender, duration of device utilization, frequency of device entry, or the intensive care unit in which the study was conducted. In no circumstance did positive cultures from any of the blood conservation devices correlate with positive culture results from any sites of clinical infection. The clinical survey demonstrated a statistically significant preference for the VAMP system, which persisted despite increased experience with the Safe Draw system.

CONCLUSIONS

The levels of microbial contamination noted in these devices were not consistent with clinical infection (defined as 10(3) cfu/mL on quantitative cultures). There was no significant difference in degree or pattern of contamination between the two devices. When utilized and changed according to the Centers for Disease Control guidelines, blood conservation devices are not harbors of infection in the critical care setting. Blood conservation devices can be used as part of a comprehensive blood conservation program in the critical care setting without undue concern for exacerbating infectious processes.