Fibrinolysis Resistance After Injury Is a Risk Factor for a Hospital-Acquired Pneumonia-Like Disease Pattern

Background: Pneumonia is associated with increased morbidity and costs in the intensive care unit (ICU). Its early identification is key for optimal outcomes, but early biomarkers are lacking. Studies suggest that fibrinolysis resistance (FR) after major abdominal surgery is linked to an increased risk of infection. Patients and Methods: Patients in a randomized controlled trial for hemorrhagic shock were evaluated for FR. Fibrinolysis resistance was quantified by thrombelastography with exogenous tissue plasminogen activator (tPA-TEG) at 24- and 48-hours post-injury and measuring LY30 (%). A receiver-operating characteristics (ROC) curve analysis was used to identify a cutoff for increased risk of pneumonia, which was then validated in ICU patients at risk for venous thromboembolism (VTE). Multivariable logistic regression was used to control for confounders. Results: Forty-nine patients in the hemorrhagic shock cohort had tPA-TEGs at 24- and 48-hours (median ISS, 27; 7% pneumonia). A composite tPA-TEG LY30 of less than 4% at 24 and 48 hours was found to be the optimal cutoff for increased risk of pneumonia. This cohort had a seven-fold increased rate of pneumonia (4% vs. 28%; p = 0.048). Eighty-eight patients in the VTE cohort had tPA-TEGs at 24 and 48 hours post-ICU admission (median ISS, 28; 6% pneumonia). The tPA-TEG LY30 of less than 4% was associated with a 10-fold increased rate of pneumonia (19% vs. 1.5%; p = 0.002). In patients with traumatic brain injury, the same association was found (33% vs. 3.2%; p = 0.006). Adjusting for confounders, the tPA-TEG persisted as a substantial risk factor for pneumonia (adjusted odds ratio [OR], 35.7; 95% confidence interval [CI], 1.9-682; p = 0.018). Conclusions: Fibrinolysis resistance quantified by tPA-TEG within 48 hours of ICU admission is associated with an increased risk of pneumonia in patients in hemorrhagic shock and those at risk for VTE. Prospective validation of the tPA-TEG LY30 optimal cutoff for pneumonia and further investigation into whether endogenous FR is a cause of an altered immunity is warranted.

The in-vitro influence of urea concentration on thromboelastrography in patients with and without end stage renal disease

BACKGROUND

End stage renal disease (ESRD) is associated with platelet dysfunction but also thromboembolic complications. The specific role of increased blood urea nitrogen (BUN) on coagulation is unclear. We aimed to characterize thromboelastography (TEG) parameters from males and females with ESRD and normal kidney function and evaluate if exogenous urea in vitro reproduced those TEG differences.

METHODS

We collected blood samples from 20 living kidney donors and 20 kidney recipients. TEG was performed without and with two increasing urea concentrations in vitro. TEG parameters were compared between recipients and donors.

RESULTS

Blood from kidney recipients showed baseline increased maximum amplitude (MA) and shortened time to maximum amplitude (TMA) compared to donors. These differences were not confirmed in females. In all patients, BUN was inversely correlated with TMA (r = -0.342; p = 0.031). In males, BUN and creatinine concentrations showed a direct correlation with MA (0.583; p = 0.007) and an inverse correlation with TMA (r = -0.520; p = 0.019). Urea in vitro decreased R-time (p = 0.005) and increased LY30 (p = 0.009) in donors but not recipients.

CONCLUSIONS

ESRD is associated with increased MA and decreased TMA on TEG. No change in MA was observed with increasing urea concentrations in vitro. Gender-specific variability in TEG parameters were observed.

Low viscoelastic clot strength, platelet transfusions, and graft dysfunction are associated with persistent postoperative ascites following liver transplantation

INTRODUCTION

High output, persistent ascites (PA) is a common complication following liver transplant (LT). Recent work has identified that platelets help maintain endothelial integrity and can decrease leakage in pathological states. We sought to assess the association of PA following LT with platelet count and platelet function.

METHODS

Clot strength (MA) is a measure of platelet function and was quantified using thrombelastography (TEG). Total drain output following surgery was recorded in 24-h intervals during the same time frame as TEG. PA was considered >1 L on POD7, as that much output prohibits drain removal.

RESULTS

105 LT recipients with moderate or high volume preoperative ascites were prospectively enrolled. PA occurred in 28%. Platelet transfusions before and after surgery were associated with PA, in addition to POD5 TEG MA and POD5 MELD score. Patients with PA had a longer hospital length of stay and an increased rate of intraabdominal infections.

CONCLUSION

Persistent ascites following liver transplant is relatively common and associated with platelet transfusions, low clot strength, and graft dysfunction.

Fibrinolysis resistance after liver transplant as a predictor of early infection

BACKGROUND

Infection is a leading cause of morbidity in liver transplant (LT). Considering that the fibrinolytic system is altered in sepsis, we investigated the relationship between fibrinolysis resistance (FR) and post-transplant infection.

METHODS

Fibrinolysis was quantified using thrombelastography (TEG) with the addition of tPA to quantify FR. FR was defined as LY30 = 0% and stratified as transient if present on POD1 or POD5 (tFR), persistent (pFR) if present on both, or no FR (nFR) if absent.

RESULTS

180 LT recipients were prospectively enrolled. 52 (29%) recipients developed infection. 72 had tFR; 37 had pFR; and 71 had nFR. Recipients with pFR had significantly greater incidence of infections (51% vs. 26% tFR vs. 20% nFR, p = 0.002). pFR was independently associated with increased odds of post-transplant infection (adjusted OR 3.39, p = 0.009).

CONCLUSIONS

Persistent fibrinolysis resistance is associated with increased risk of post-transplant infection.

Indications and Outcomes of Single-Pedicle vs 2-Pedicle Thigh Free Flaps in Head and Neck Reconstruction

Importance

Flap choice and design are crucial to the success of free flap reconstruction of the head and neck. These are dependent on donor and recipient site characteristics.

Objective

To demonstrate indications and outcomes of a single-pedicle anterolateral thigh flap (standard ALT flap) vs a thigh free flap with 2 pedicles in head and neck reconstruction.

Design, Setting, and Participants

A retrospective case series of consecutive patients treated in a tertiary academic care center between October 2011 and June 2017 by a single reconstructive microsurgeon was carried out. Eighty-one patients underwent reconstruction of a cutaneous and/or mucosal defect of the head and neck. Patients with a composite mandibular defect who received both a fibular flap and a thigh flap were excluded. Those with less than 6 months of follow-up were excluded.

Main Outcomes and Measures

Patient characteristics and clinical variables, including age, sex, primary diagnosis/indication for reconstruction, type of flap, dimensions of flap, and number of perforators in the flap, were collected. Optimal cutoff values to quantitate the differences in length and width between the standard ALT and 2-pedicle thigh flaps were determined using receiver operating characteristic (ROC) curve analysis and the Youden Index. The types of flap were compared to determine any difference in flap complications including flap loss, venous congestion, and poor wound healing.

Results

Of the 81 patients (mean [SD] age, 58.2 [15.9] years; 62 [76.5%] men), 57 and 18 patients were reconstructed with a standard ALT flap and a thigh flap with 2 pedicles, respectively. Six patients underwent multiple simultaneous thigh (MST) flaps. Defect size (width ≥12 cm, standard ALT: 95% CI, 7.6-9.7; thigh flap with 2 pedicles: 95% CI, 7.0-17.4; P = .02; length ≥17 cm, standard ALT: 95% CI, 11.9-15.2; thigh flap with 2 pedicles: 95% CI, 13.6-30.0; P = .001), the presence of divergent mucosal defects, and through-and-through oral cavity/pharyngeal defects were associated with the use of 2 pedicles. Within groups of thigh flaps with 2 pedicles and MST flaps, there were no flap complications (ie, partial loss, venous congestion, or wound healing issues from poor perfusion).

Conclusions and Relevance

Harvesting a thigh flap with 2 pedicles has the potential to reduce flap complications and should be considered for divergent and wide or long defects. Width and length measurements respectively of 12 cm and 17 cm are reasonable numbers to initially consider when deciding whether to include a second pedicle.

Level of Evidence

3.

Principles of radiographic selection and interpretation

When performing a radiologic examination, it is important for the clinician to follow a diagnostic sequence. Specific viewing principles are necessary to create the proper physical environment to obtain the most information from the radiographs. The selection of radiologic examination must be based on the ALARA (As Low As Reasonably Achievable) principle, and the clinician should use a method approach to radiologic interpretation.