Characterization of platelet concentrations and evaluation of risk factors for thrombocytopenia following traumatic injury

Introduction

Thrombocytopenia is common in critically ill trauma patients and can lead to potentially broad differentials, including major bleeding, hemodilution, extracorporeal circuit losses, heparin-induced thrombocytopenia, and more. Understanding the normal time course of platelet decline and recovery may delineate thrombocytopenia(HIT) secondary to traumatic injury versus other inciting factors.

Methods

This retrospective study included trauma patients admitted over a 1-year period. The primary aim was characterizing the effect of trauma on platelet concentration and thrombocytopenia incidence in the first 30 days following injury. Thrombocytopenia was defined as platelet concentration <150 × 109/L. A secondary aim was evaluating significant factors contributing to thrombocytopenia.

Results

A total of 225 patients were included. Thrombocytopenia occurred in 67.3% of patients, and a platelet decline of 50% or greater occurred in 44%. Decrease in platelet concentration was significant from day 1 to day 4 (mean ± SD, 232 ± 86 vs 142 ± 76 × 109/L; p = .001). Platelets recovered to baseline on day 8 and peaked on day 16. Packed red blood cell or platelet transfusion, continuous renal replacement therapy, and acute liver injury independently predicted a ≥50% platelet decrease. HIT was not diagnosed in any patients.

Conclusion

Platelet nadir likely occurs approximately 4 days after injury and recovers relatively quickly thereafter. More studies are needed to evaluate the magnitude of effect on thrombocytopenia by factors beyond trauma.

The sequential organ failure assessment (SOFA) score is an effective triage marker following staggered paracetamol (acetaminophen) overdose

BACKGROUND

The sequential organ failure assessment (SOFA) score is an effective triage marker following single time point paracetamol (acetaminophen) overdose, but has not been evaluated following staggered (multiple supratherapeutic doses over >8 h, resulting in cumulative dose of >4 g/day) overdoses.

AIM

To evaluate the prognostic accuracy of the SOFA score following staggered paracetamol overdose.

METHODS

Time-course analysis of 50 staggered paracetamol overdoses admitted to a tertiary liver centre. Individual timed laboratory samples were correlated with corresponding clinical parameters and the daily SOFA scores were calculated.

RESULTS

A total of 39/50 (78%) patients developed hepatic encephalopathy. The area under the SOFA receiver operator characteristic for death/liver transplantation was 87.4 (95% CI 73.2-95.7), 94.3 (95% CI 82.5-99.1), and 98.4 (95% CI 84.3-100.0) at 0, 24 and 48 h, respectively, postadmission. A SOFA score of <6 at tertiary care admission predicted survival with a sensitivity of 100.0% (95% CI 76.8-100.0) and specificity of 58.3% (95% CI 40.8-74.5), compared with 85.7% (95% CI 60.6-97.4) and 75.0% (95% CI 65.2-79.5) , respectively, for the modified Kings College criteria. Only 2/21 patients with an admission SOFA score <6 required renal replacement therapy or intracerebral pressure monitoring. SOFA significantly outperformed the Model for End-stage Liver Disease, but not APACHE II, at 0, 24-and 48-h following admission.

CONCLUSIONS

A SOFA score <6 at tertiary care admission following a staggered paracetamol overdose, is associated with a good prognosis. Both the SOFA and APACHE II scores could improve triage of high-risk staggered paracetamol overdose patients.

The sequential organ failure assessment (SOFA) score is prognostically superior to the model for end-stage liver disease (MELD) and MELD variants following paracetamol (acetaminophen) overdose

BACKGROUND

The prognostic value of the model for end-stage liver disease (MELD) and sodium-based MELD variants in predicting survival following paracetamol overdose remains unclear.

AIM

To examine the prognostic accuracy of sodium-based MELD variants in paracetamol-induced acute liver injury compared with the sequential organ failure assessment (SOFA) score.

METHODS

Retrospective analysis of 138 single time point paracetamol overdoses admitted to a tertiary liver centre. Individual laboratory samples were correlated with the corresponding clinical parameters in relation to time post-overdose, and the daily MELD, MELD-Na, MELDNa, MESO, iMELD, UKELD, updated MELD and SOFA scores were calculated.

RESULTS

Sixty-six (47.8%) patients developed hepatic encephalopathy, of whom 7 were transplanted and 21 died without liver transplantation. SOFA had a significantly greater area under the receiver operator characteristic for the prediction of spontaneous survival compared with MELD at both 72 (P = 0.024) and 96 (P = 0.017) h post-overdose. None of the sodium-based MELD variants improved the prognostic accuracy of MELD. A SOFA score >6 by 72 h or >7 by 96 h, post-overdose predicted death/transplantation with a negative predictive value of 96.9 (95% CI 90.2-99.4) and 98.8 (95% CI 93.6-99.9) respectively. SOFA and MELD had similar accuracy for predicting the development of hepatic encephalopathy (P = 0.493).

CONCLUSIONS

The SOFA score is superior to MELD in predicting spontaneous survival following paracetamol-induced acute liver injury. Modification of the MELD score to include serum sodium does not improve prognostic accuracy in this setting. SOFA may have potential as a quantitative triage marker following paracetamol overdose.

The systemic inflammatory response syndrome and sequential organ failure assessment scores are effective triage markers following paracetamol (acetaminophen) overdose

BACKGROUND

The systemic inflammatory response syndrome (SIRS) and sequential organ failure assessment (SOFA) scores are widely used as prognostic markers in critical care settings and could improve triage of high-risk paracetamol (acetaminophen) overdose patients.

AIM

To evaluate the prognostic accuracy of the SIRS and SOFA scores following single time point paracetamol overdose.

METHODS

Analysis of 100 single time point paracetamol overdoses admitted to a tertiary liver centre, with subsequent prospective validation of identified thresholds. Individual laboratory samples were correlated with the corresponding clinical parameters in relation to time post-overdose, and the daily SOFA and SIRS scores calculated.

RESULTS

A total of 74 (74%) patients developed the SIRS, which occurred significantly earlier in patients who died (n=21) compared with spontaneous survivors (n=53, P=0.05). The SIRS occurred in 70 (70%) patients by 96h post-overdose, with a 30% mortality rate; compared with 0% mortality in the 30 non-SIRS patients (P=0.001). Median SOFA scores were significantly higher in nonsurvivors at 48 (P=0.009), 72 (P<0.001), and 96h (P<0.001). A SOFA score >7 during the first 96h post-overdose predicted death/transplantation with a sensitivity of 95.0 (95% CI 78.5-99.1) and specificity of 70.5 (95% CI 66.3-71.6). A validation cohort of 38 single time point paracetamol overdoses confirmed the extremely high negative predictive value of both the SIRS and SOFA thresholds.

CONCLUSIONS

The absence of either a SOFA score >7 or a SIRS response during the first 96 h following paracetamol overdose could improve triage and reduce transfers of lower risk patients to tertiary liver centres.