Central venous catheters: Which, when and how

Short-term or long-term CVCs are now considered the standard of practice for the administration of chemotherapy, fluid therapy, antibiotic therapy, and parenteral nutrition. Central venous access catheters are broadly divided into tunneled or non-tunneled catheters. Tunneled catheters can be further subdivided into totally implanted and totally not implanted devices. Device selection generally depends on various factors such as availability of peripheral veins, expected duration of therapy, and desired flow rate. Ultrasound-guided access is the safest technique for central venous access compared to the landmark technique and departments should strive to for a 100% ultrasound guided access. This review gives a basic overview of the differences of CVC catheters including PICCs, Hickman-catheters and port-catheters along with the criteria for CVC selection. It will also describe technical tips on placement of CVCs. Finally, it aims to highlight complications which are associated with CVC placement and options to treat or prevent them.

Comparison of three transfusion protocols prior to central venous catheterization in patients with cirrhosis: A randomized controlled trial

BACKGROUND

Transfusion of blood components prior to invasive procedures in cirrhosis patients is high and associated with adverse events.

OBJECTIVES

We compared three transfusion strategies prior to central venous catheterization in cirrhosis patients.

PATIENTS/METHODS

Single center randomized trial that included critically ill cirrhosis patients with indication for central venous line in a tertiary private hospital in Brazil.

INTERVENTIONS

Restrictive protocol, thromboelastometry-guided protocol, or usual care (based on coagulogram). The primary endpoint was the proportion of patients transfused with any blood component (ie, fresh frozen plasma, platelets, or cryoprecipitate). The secondary endpoints included incidence of bleeding and transfusion-related adverse events.

RESULTS

A total of 57 patients (19 per group; 64.9% male; mean age, 53.4 ± 11.3 years) were enrolled. Prior to catheterization, 3/19 (15.8%) in the restrictive arm, 13/19 (68.4%) in the thromboelastometry-guided arm, and 14/19 (73.7%) in the coagulogram-guided arm received blood transfusion (odds ratio [OR], 0.07; 95% confidence interval [CI], 0.01-0.45; P = .002 for restrictive versus coagulogram-guided arm; OR, 0.09; 95% CI, 0.01-0.56; P = .006 for restrictive versus thromboelastometry-guided arm; and OR, 0.77; 95% CI, 0.14-4.15; P = .931 for thromboelastometry-guided versus coagulogram-guided arm). The restrictive protocol was cost saving. No difference in bleeding, length of stay, mortality, and transfusion-related adverse events was found.

CONCLUSIONS

The use of a restrictive strategy is associated with a reduction in transfusion prior to central venous catheterization and costs in critically ill cirrhosis patients. No effect on bleeding was found among the groups.

Fresh frozen plasma transfusion in patients with cirrhosis and coagulopathy: Effect on conventional coagulation tests and thrombomodulin-modified thrombin generation

BACKGROUND & AIMS

The efficacy of fresh frozen plasma (FFP) transfusion in enhancing thrombin generation in patients with cirrhosis and impaired conventional coagulation tests has not been sufficiently explored. Thus, we aimed to assess the effect of FFP transfusion on thrombin generation in these patients.

METHODS

Fifty-three consecutive patients receiving a standard dose of FFP to treat bleeding and/or before invasive procedures - if international normalized ratio (INR)/prothrombin time (PT) ratio were ≥1.5 - were prospectively enrolled. The primary endpoint was the amelioration of endogenous thrombin potential (ETP) with thrombomodulin (ETP-TM) after transfusion, which corresponds to the total amount of generated thrombin. INR/PT ratio and activated partial thromboplastin time (aPTT) were also assessed before and after transfusion.

RESULTS

FFP enhanced ETP-TM by 5.7%, from 973 (731-1,258) to 1,028 (885-1,343 nM × min; p = 0.019). Before transfusion, evidence of normal or high ETP-TM was found in 94% of patients, even in those with bacterial infections. Only 1 (1.9%) patient had ETP-TM values reverting to the normal range after transfusion. Notably, no patients with low ETP-TM had bleeding. The median decrease in ETP-TM was 8.3% and the mean was 12.8% in 18 (34%) patients after transfusion (from 1,225 [1,071-1,537] to 1,124 [812-1,370] nM × min; p ≤0.0001). Similar responses to FFP transfusion were observed in patients with compensated and acute decompensated cirrhosis, acute-on-chronic liver failure, infection or shock. FFP significantly ameliorated INR and aPTT values (p <0.0001), but in a minority of patients the values were reduced to less than the cut-off point of 1.5.

CONCLUSIONS

FFP transfusion enhanced thrombin generation and ameliorated conventional coagulation tests to normal values in a limited number of patients, and slightly decreased thrombin generation in 34% of cases.

LAY SUMMARY

Transfusion of fresh frozen plasma in patients with cirrhosis only slightly improves coagulation test values in a limited number of patients and even appears to worsen them in a third of cases. Transfusion for the purpose of preventing or treating bleeding events could cause inherent risks and costs without clear benefits.

Plasma transfusions prior to insertion of central lines for people with abnormal coagulation

BACKGROUND

The insertion of central venous catheters (CVCs) may be associated with peri- and post-procedural bleeding. People who require a central line often have disorders of coagulation as a result of their underlying illness, co-morbidities or the effects of treatment. Clinical practice in some institutions is to mitigate the risk of bleeding in these patients by prophylactically transfusing fresh frozen plasma (FFP) in order to correct clotting factor deficiencies prior to central line insertion. However, FFP transfusion is not without risk, and it remains unclear whether this intervention is associated with reduced rates of bleeding or other clinically-meaningful outcomes.

OBJECTIVES

To assess the effect of different prophylactic plasma transfusion regimens prior to central line insertion in people with abnormal coagulation.

SEARCH METHODS

We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 3), PubMed (e-publications only), Ovid MEDLINE (from 1946), Ovid Embase (from 1974), the Transfusion Evidence Library (from 1950) and ongoing trial databases to 1 March 2016.

SELECTION CRITERIA

We included RCTs involving transfusions of plasma to prevent bleeding in people of any age with abnormal coagulation requiring insertion of a central venous catheter, published in English.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We identified four trials eligible for inclusion, of which three are ongoing. We did not exclude any studies because they were not published in English.The included study randomised 81 adults in intensive care whose INR (International Normalised Ratio) was greater than or equal to 1.5 to no FFP or to a single dose of 12 mL/kg FFP prior to undergoing central venous catheterisation (58 participants) or other invasive procedure (23 participants). It is the subgroup of 58 adults undergoing CVC insertion that were included in this review, the study authors provided unpublished data for this review's outcomes.The quality of the evidence was low or very low across different outcomes according to the GRADE methodology. The included study was at high risk of bias due to lack of blinding of participants and personnel and imbalance in the number of participants who had liver disease between study arms.There was insufficient evidence to determine a difference in major procedure-related bleeding within 24 hours (one RCT; 58 participants; no events in either study arm, very low-quality evidence). We are very uncertain whether FFP reduces minor procedure-related bleeding within 24 hours of the study (one RCT; 58 participants, RR 0.67, 95% CI 0.12 to 3.70, very low-quality evidence).No studies were found that looked at: all-cause mortality; the proportion of participants receiving plasma or red cell transfusions; serious adverse reactions (transfusion or line-related complications); number of days in hospital; change in INR; or quality of life.The three ongoing studies are still recruiting participants (expected recruitment: up to 355 participants in total). and are due to be completed by February 2018.

AUTHORS' CONCLUSIONS

There is only very limited evidence from one RCT to inform the decision whether or not to administer prophylactic plasma prior to central venous catheterisation for people with abnormal coagulation. It is not possible from the current RCT evidence to recommend whether or not prophylactic plasma transfusion is beneficial or harmful in this situation. The three ongoing RCTs will not be able to answer this review's questions, because they are small studies and do not address all of the comparisons included in this review (355 participants in total). To detect an increase in the proportion of participants who had major bleeding from 1 in 100 to 2 in 100 would require a study containing at least 4634 participants (80% power, 5% significance).

Risk of Procedural Hemorrhage

Patients who are critically ill and hospitalized often require invasive procedures as a part of their medical care. Each procedure carries a unique set of risks and associated complications, but common to all of them is the risk of hemorrhage. Central venous catheterization, arterial catheterization, paracentesis, thoracentesis, tube thoracostomy, and lumbar puncture constitute a majority of the procedures performed in patients who are hospitalized. In this article, the authors will discuss the risk factors for bleeding complications from each of these procedures and methods to minimize risk. Physicians often correct coagulopathy prior to procedures to decrease bleeding risk, but there is minimal evidence to support this practice.

Mathematical model and calculation to predict the effect of prophylactic plasma transfusion on change in international normalized ratio in critically ill patients with coagulopathy

BACKGROUND

Plasma transfusion is often used prophylactically in patients with coagulopathy. However, the doses transfused may not be adequate to normalize hemostatic tests, which are commonly used as surrogate markers in practice. Currently, there is no reliable way to predict the posttransfusion international normalized ratio (INR) after plasma transfusion. Therefore, our aim was to develop and validate a formula that can reliably estimate post-plasma transfusion INR.

STUDY DESIGN AND METHODS

A compartmental model was developed using demographic (sex, height, weight) and laboratory variables (hematocrit [Hct], INRinitial , and plasma volume transfused). The formula was validated using a data set from a multicenter trial conducted between May 2010 and June 2013 in critically ill, nonbleeding patients with coagulopathy, receiving prophylactic plasma transfusions. INR was measured just before and immediately after plasma transfusion.

RESULTS

Initial plasma volume is calculated using the patient's Hct and blood volume (derived from Nadler's formula). The estimated immediate posttransfusion INR is then calculated as [Formula: see text] There was a significant agreement between the model predictions and the actual INR measurements after transfusion. A total of 83% of the predictions were within the acceptable range of variation. Furthermore, there was no proportional difference or systemic bias between the predictions and the actual INR measurements.

CONCLUSION

This mathematical formula estimates posttransfusion INR after a certain volume of plasma transfusion with a good predictive ability. This formula, which only requires basic demographic and laboratory variables, may help the physicians to determine the volume of plasma required for a specific target INR in stable, nonbleeding patients.

Plasma transfusions prior to insertion of central lines for patients with abnormal coagulation

This is the protocol for a review and there is no abstract. The objectives are as follows: To assess the effect of different prophylactic plasma transfusion regimens prior to central line insertion in patients with abnormal coagulation.

Fresh frozen plasma transfusion fails to influence the hemostatic balance in critically ill patients with a coagulopathy

BACKGROUND

Coagulopathy has a high prevalence in critically ill patients. An increased International Normalized Ratio (INR) is a common trigger to transfuse fresh frozen plasma (FFP), even in the absence of bleeding. Therefore, FFP is frequently administered to these patients. However, the efficacy of FFP in correcting hemostatic disorders in non-bleeding recipients has been questioned.

OBJECTIVES

To assess whether INR prolongation parallels changes in the results of other tests investigating hemostasis, and to evaluate the coagulant effects of a fixed dose of FFP in non-bleeding critically ill patients with a coagulopathy.

METHODS

Markers of coagulation, individual factor levels and levels of natural anticoagulants were measured. Also, thrombin generation and thromboelastometry (ROTEM) assays were performed before and after FFP transfusion (12 mL kg(-1) ) to 38 non-bleeding critically ill patients with an increased INR (1.5-3.0).

RESULTS

At baseline, levels of factor II, FV, FVII, protein C, protein S and antithrombin were reduced, and thrombin generation was impaired. ROTEM variables were within reference ranges, except for a prolonged INTEM clot formation time. FFP transfusion increased the levels of coagulation factors (FII, 34% [interquartile range (IQR) 26-46] before vs. 44% [IQR 38-52] after; FV, 48% [IQR 28-76] before vs. 58% [IQR 44-90] after; and FVII, 25% [IQR 16-38] before vs. 37% [IQR 28-55] after), and the levels of anticoagulant proteins. Thrombin generation was unaffected by FFP transfusion (endogenous thrombin potential, 72% [IQR 51-88] before vs. 71% [IQR 42-89] after), whereas ROTEM EXTEM clotting time and maximum clot firmness slightly improved in response to FFP.

CONCLUSION

In non-bleeding critically ill patients with a coagulopathy, FFP transfusion failed to induce a more procoagulant state.

Peri-procedural management of bleeding risks in critical care patients: A local audit and national survey

Estimation of bleeding risk in critical care patients undergoing interventional radiological procedures is frequently made on the basis of blood tests. If these tests are abnormal, fresh frozen plasma and/or platelet transfusions may be given to reduce the risk of bleeding. We performed an audit and national survey of the use of fresh frozen plasma and platelet transfusions prior to interventional radiological procedures. We identified 68 consecutive chest, abdominal or pelvic drain insertions in 54 critical care patients between 2008 and 2011 at a single intensive care unit. Eight (12.3%) patients were transfused fresh frozen plasma prior to drain insertion despite having a prothrombin time below 22 s. One patient with a prothrombin time above this threshold received fresh frozen plasma. One patient received a platelet transfusion, at double dose, despite a platelet count above 50 × 109/l. A national survey of interventional radiologists demonstrated extensive variability in safe thresholds for invasive procedures and usage of fresh frozen plasma. There is a need for further clarification around coagulopathy and interventional radiology in the critical care setting.

Transfusion of fresh-frozen plasma in critically ill patients with a coagulopathy before invasive procedures: a randomized clinical trial (CME)

BACKGROUND

Prophylactic use of fresh-frozen plasma (FFP) is common practice in patients with a coagulopathy undergoing an invasive procedure. Evidence that FFP prevents bleeding is lacking, while risks of transfusion-related morbidity after FFP have been well demonstrated. We aimed to assess whether omitting prophylactic FFP transfusion in nonbleeding critically ill patients with a coagulopathy who undergo an intervention is noninferior to a prophylactic transfusion of FFP.

STUDY DESIGN AND METHODS

A multicenter randomized open-label trial with blinded endpoint evaluation was performed in critically ill patients with a prolonged international normalized ratio (INR; 1.5-3.0). Patients undergoing placement of a central venous catheter, percutaneous tracheostomy, chest tube, or abscess drainage were eligible. Patients with clinically overt bleeding, thrombocytopenia, or therapeutic use of anticoagulants were excluded. Patients were randomly assigned to omitting or administering a prophylactic transfusion of FFP (12 mL/kg). Outcomes were occurrence of postprocedural bleeding complications, INR correction, and occurrence of lung injury.

RESULTS

Due to slow inclusion, the trial was stopped before the predefined target enrollment was reached. Eighty-one patients were randomly assigned, 40 to FFP and 41 to no FFP transfusion. Incidence of bleeding did not differ between groups, with a total of one major and 13 minor bleedings (p = 0.08 for noninferiority). FFP transfusion resulted in a reduction of INR to less than 1.5 in 54% of transfused patients. No differences in lung injury scores were observed.

CONCLUSION

In critically ill patients undergoing an invasive procedure, no difference in bleeding complications was found regardless whether FFP was prophylactically administered or not.

Predictors of unattempted central venous catheterization in septic patients eligible for early goal-directed therapy

INTRODUCTION

Central venous catheterization (CVC) can be an important component of the management of patients with severe sepsis and septic shock. CVC, however, is a time- and resource-intensive procedure associated with serious complications. The effects of the absence of shock or the presence of relative contraindications on undertaking central line placement in septic emergency department (ED) patients eligible for early goal-directed therapy (EGDT) have not been well described. We sought to determine the association of relative normotension (sustained systolic blood pressure >90 mmHg independent of or in response to an initial crystalloid resuscitation of 20 mL/kg), obesity (body mass index [BMI] ≥30), moderate thrombocytopenia (platelet count <50,000 per μL), and coagulopathy (international normalized ratio ≥2.0) with unattempted CVC in EGDT-eligible patients.

METHODS

This was a retrospective cohort study of 421 adults who met EGDT criteria in 5 community EDs over a period of 13 months. We compared patients with attempted thoracic (internal jugular or subclavian) CVC with those who did not undergo an attempted thoracic line. We also compared patients with any attempted CVC (either thoracic or femoral) with those who did not undergo any attempted central line. We used multivariate logistic regression analysis to calculate adjusted odd ratios (AORs).

RESULTS

In our study, 364 (86.5%) patients underwent attempted thoracic CVC and 57 (13.5%) did not. Relative normotension was significantly associated with unattempted thoracic CVC (AOR 2.6 95% confidence interval [CI], 1.6-4.3), as were moderate thrombocytopenia (AOR 3.9; 95% CI, 1.5-10.1) and coagulopathy (AOR 2.7; 95% CI, 1.3-5.6). When assessing for attempted catheterization of any central venous site (thoracic or femoral), 382 (90.7%) patients underwent attempted catheterization and 39 (9.3%) patients did not. Relative normotension (AOR 2.3; 95% CI, 1.2-4.5) and moderate thrombocytopenia (AOR 3.9; 95% CI, 1.5-10.3) were significantly associated with unattempted CVC, whereas coagulopathy was not (AOR 0.6; 95% CI, 0.2-1.8). Obesity was not significantly associated with unattempted CVC, either thoracic in location or at any site.

CONCLUSION

Septic patients eligible for EGDT with relative normotension and those with moderate thrombocytopenia were less likely to undergo attempted CVC at any site. Those with coagulopathy were also less likely to undergo attempted thoracic central line placement. Knowledge of the decision-making calculus at play for physicians considering central venous catheterization in this population can help inform physician education and performance improvement programs.

Coagulation pattern in critical liver dysfunction

PURPOSE OF REVIEW

This article reviews the current literature dealing with pathophysiology, diagnostics, bleeding management, and thromboprophylaxis in patients with acute and chronic liver dysfunction.

RECENT FINDINGS

Routine coagulation tests such as prothrombin time and International Normalized Ratio (INR) are not able to define whether a patient with critical liver dysfunction is hypocoagulable or hypercoagulable and are not able to predict the risk of bleeding in patients with liver dysfunction. Therefore, prophylactic transfusion of fresh frozen plasma and platelets in order to correct laboratory values is not appropriate. Notably, patients with liver dysfunction and increased INR are not 'autoanticoagulated'. In contrast, thrombin generation assays in the presence and absence of thrombomodulin or Protac, a snake venom that activates protein C in a manner similar to thrombomodulin, as well as viscoelastic tests (thrombelastography/thromboelastometry) indicate that patients with liver dysfunction are rather hypercoagulable with the inherent risk of thrombosis.

SUMMARY

Coagulopathy in patients with critical liver dysfunction is complex and can quickly decompensate to bleeding as well as to thrombosis. Both are associated with worse outcome. Hemostatic interventions should only be performed in case of clinically relevant bleeding and thromboprophylaxis should strongly be considered.