Risk markers for thrombocytopenia in critically ill patients: a prospective analysis

Relationship between thrombocytopenia and prognosis in children with septic shock: a retrospective cohort study

Septic shock is a life-threatening disease worldwide often associated with thrombocytopenia. Platelets play a crucial role in bridging the gap between immunity, coagulation, and endothelial cell activation, potentially influencing the course of the disease. However, there are few studies specifically evaluating the impact of thrombocytopenia on the prognosis of pediatric patients. Therefore, the study investigates effects of early thrombocytopenia in the prognosis of children with septic shock. Pediatric patients with septic shock from 2015 to 2022 were included monocentrically. Thrombocytopenia was defined as a platelet count of <100 × 109/L during the first 24 hours of septic shock onset. The primary outcome was the 28-day mortality. Propensity score matching was used to pair patients with different platelet counts on admission but comparable disease severity. A total of 419 pediatric patients were included in the analysis. Patients with thrombocytopenia had higher 28-day mortality (55.5% vs. 38.7%, p = .005) compared to patients with no thrombocytopenia. Thrombocytopenia was associated with reduced 28-PICU free days (median value, 0 vs. 13 days, p = .003) and 28-ventilator-free (median value, 0 vs. 19 days, p = .001) days. Among thrombocytopenia patients, those with platelet count ≤50 × 109/L had a higher 28-day mortality rate (63.6% vs. 45%, p = .02). Multiple logistic regression showed that elevated lactate (adjusted odds ratio (OR) = 1.11; 95% confidence interval (CI): 1.04-1.17; P <0.001) and white blood cell (WBC) count (OR = 0.97; 95% CI: 0.95-0.99; p = .003) were independent risk factors for the development of thrombocytopenia. Thrombocytopenia group had increased bleeding events, blood product transfusions, and development of organ failure. In Kaplan-Meier survival estimates, survival probabilities at 28 days were greater in patients without thrombocytopenia (p value from the log-rank test, p = .004). There were no significant differences in the type of pathogenic microorganisms and the site of infection between patients with and without thrombocytopenia. In conclusion, thrombocytopenia within 24 hours of shock onset is associated with an increased risk of 28-day mortality in pediatric patients with septic shock.

Development and Validation Nomogram for Predicting the Survival of Patients with Thrombocytopenia in Intensive Care Units

Background

The number of patients with thrombocytopenia (TCP) is relatively high in intensive care units (ICUs). It is therefore necessary to evaluate the prognostic risk of such patients.

Aim

This study investigated the risk factors affecting the survival of patients with TCP in the ICU. Using the findings of this investigation, we developed and validated a risk prediction model.

Methods

We evaluated patients admitted to the ICU who presented with TCP. We used LASSO regression to identify important clinical indicators. Based on these indicators, we developed a prediction model complete with a nomogram for the development cohort set. We then evaluated the mode's accuracy using a receiver operating characteristic (ROC) curve, calibration curves, and decision curve analysis (DCA) in a validation cohort.

Results

A total of 141 cases of ICU TCP were included in the sample, of which 47 involved death of the patient. Clinical results were as follows: N (HR 0.91, 95% CI 0.86-0.97, P=0.003); TBIL (HR 1.98, 95% CI 1.02-1.99, P=0.048); APACHE II (HR 1.94, 95% CI 1.39, 2.48, P=0.045); WPRN (HR 6.22, 95% CI 2.86-13.53, P<0.001); WTOST (HR 0.56, 95% CI 0.21-1.46, P<0.001); and DMV [HR1.87, 95% CI 1.12-2.33]. The prediction model yielded an area under the curve (AUC) of 0.918 (95% CI 0.863-0.974) in the development cohort and 0.926 (95% CI 0.849-0.994) in the validation cohort. Application of the nomogram in the validation cohort gave good discrimination (C-index 0.853, 95% CI 0.810-0.922) and good calibration. DCA indicated that the nomogram was clinically useful.

Conclusion

The individualized nomogram developed through our analysis demonstrated effective prognostic prediction for patients with TCP in ICUs. Use of this prediction metric may reduce TCP-related morbidity and mortality in ICUs.

Continuous Versus Intermittent Linezolid Infusion for Critically Ill Patients with Hospital-Acquired and Ventilator-Associated Pneumonia: Efficacy and Safety Challenges

High variability of linezolid blood concentrations with partial subtherapeutic levels was observed in critically ill patients who received a standard intravenous dose of linezolid, contributing to drug resistance and toxicity. Continuous infusions of linezolid have been suggested as an alternative and provide good serum and alveolar levels without fluctuations in trough concentration. This study aimed to assess the effectiveness and safety of continuous linezolid infusion versus the standard regimen in critically ill patients. A prospective randomized controlled study was conducted on 179 patients with nosocomial pneumonia. Patients were randomized into two groups. The first group received IV linezolid 600 mg twice daily, while the second group received 600 mg IV as a loading dose, followed by a continuous infusion of 1200 mg/day (50 mg/h) for at least 8−10 days. The continuous infusion group showed a higher clinical cure rate than the intermittent infusion group (p = 0.046). Furthermore, efficacy was proven by greater improvement of P/F ratio (p = 0.030) on day 7 of treatment, a lower incidence of developing sepsis after beginning treatment (p = 0.009), and a shorter time to reach clinical cure (p < 0.001). Hematological parameters were also assessed during the treatment to evaluate the safety between the two groups. The incidence of thrombocytopenia was significantly lower in the continuous infusion group than in the intermittent infusion group. In addition, a stepwise logistic regression model revealed that the intermittent infusion of linezolid was significantly associated with thrombocytopenia (OR =4.128; 95% CI = 1.681−10.139; p =0.001). The current study is the first to assess the clinical aspects of continuous infusion of linezolid beyond pharmacokinetic studies. Continuous infusion of linezolid outperforms intermittent delivery in safety and improves clinical effectiveness in critically ill patients with Gram-positive nosocomial pneumonia.

Accuracy of a modified 4Ts score in predicting heparin-induced thrombocytopenia in critically ill patients: A pilot study

PURPOSE

Thrombocytopenia is common among critically ill patients and heparin-induced thrombocytopenia (HIT) is often on the differential. Professional guidelines recommend calculating a pre-test probability score before performing HIT testing. The 4Ts score is widely utilized but accuracy has been questioned in critically ill patients. The HIT Expert Probability (HEP) score is available, but complexity limits use. Our objective was to compare a modified intensive care unit (ICU)-4Ts score to available scoring tools.

MATERIALS AND METHODS

This was a single-center retrospective pilot study. Adult ICU patients that were tested for HIT and had a documented 4Ts score were included. A blinded investigator retrospectively calculated the HEP and ICU-4Ts score. Receiver operating characteristics (ROC) area under the curve (AUC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were compared.

RESULTS

In 194 included patients, ROC AUC was significantly higher for the ICU-4Ts compared to the 4Ts score (0.80 versus 0.66, respectively; p = 0.044). The ICU-4Ts score had the highest specificity, PPV, and NPV. The sensitivity was similar between the HEP and ICU-4Ts score.

CONCLUSIONS

The ICU-4Ts score better predicted the diagnosis of HIT compared to the 4Ts score. Prospective validation studies are needed to confirm these results.

Higher Prevalence of Concurrent Thrombocytopenia in Patients Receiving Continuous Renal Replacement Therapy in the Cardiac Intensive Care Unit

INTRODUCTION

Thrombocytopenia (TCP) is a common finding in patients receiving continuous renal replacement therapy (CRRT).

OBJECTIVE

The purpose of this study was to assess the nature of TCP in patients receiving CRRT.

METHODS

This is a single-center case-control observational study of 795 patients involving over 166,950 h of delivered CRRT at Johns Hopkins Hospital. Concurrent TCP in patients receiving CRRT was defined as a decrease in platelet count of ≥50% any time within 72 h of initiation of CRRT with strict exclusion criteria.

RESULTS

There was a higher incidence of TCP in the cardiac intensive care unit (CICU) (22.5%) compared to medical ICU (MICU) (13.1%). Using logistic regression, the odds of developing concurrent TCP in patients receiving CRRT was 2.46 (95% CI 1.32-3.57, p < 0.05) times higher in the CICU compared with the MICU. There was no difference in the incidence of severe or profound TCP or timing of acute TCP between the CICU and MICU.

CONCLUSION

Safe delivery of dialysis care in the ICU is paramount and creating awareness of potential risks such as concurrent TCP in patients receiving CRRT should be part of this care.

Thrombocytopenia in intensive care unit patients: A scoping review

BACKGROUND

Thrombocytopenia is frequent in intensive care unit (ICU) patients and may be associated with adverse outcomes. We aimed to assess the incidence, risk factors, and outcomes associated with thrombocytopenia in adult ICU patients.

METHODS

We conducted a scoping review in accordance with the Preferred Reporting Items for Systematic Review and Meta-analyses extension for Scoping Reviews (PRISMA-ScR) and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. We included study reports on adult ICU patients with thrombocytopenia and assessed patient-important outcomes, including mortality and health-related quality-of-life.

RESULTS

We included a total of 70 studies comprising a total of 215 098 patients; 57 were cohort studies. The incidence of thrombocytopenia varied from 8 to 56 per 100 admissions (very low quality of evidence). We identified several risk factors including age, sepsis, and higher disease severity (low quality of evidence). Thrombocytopenia was associated with bleeding, use of life support, length of stay in the ICU, and increased mortality (low/very low quality of evidence). Data on platelet transfusion before invasive procedures and transfusion thresholds were limited. No studies assessed the benefits and harms of thromboprophylaxis in ICU patients with thrombocytopenia.

CONCLUSIONS

Thrombocytopenia is common and associated with increased morbidity and mortality in adult ICU patients. Several risk factors for thrombocytopenia exists, but the evidence-base on management strategies, including transfusion thresholds and thromboprophylaxis in ICU patients is very limited.

Thrombocytopenia in 737 adult intensive care unit patients: A real-world study of associated factors, drugs, platelet transfusion, and clinical outcome

Objective:

We aimed to identify and represent factors associated with thrombocytopenia in intensive care unit, especially the pathogens and drugs related to severe and extremely thrombocytopenia. Then, we aim to compare the mortality of platelet transfusion and non-transfusion in patients with different degrees of thrombocytopenia.

Methods:

We identified all thrombocytopenic patients in intensive care unit by using platelet-specific values and then extracted electronic health records from our Hospital Information System. Data were statistically analyzed with t test, chi-square test, and logistic regression.

Results:

We found that infections (32.7%) were the most frequent cause associated with thrombocytopenia, followed by sepsis shock (3.93%) and blood loss (2.99%). Meanwhile, antifungals (p = 0.002) and bacterial infection (p = 0.037) were associated with severe and extremely severe thrombocytopenia. Finally, we found that the mortality of platelet transfusion and non-transfusion in patients was statistically significant for patients with platelet counts between 30 and 49/nL (χ² = 9.719, p = 0.002).

Conclusion:

Infection and sepsis emerged as two primary factors associated with thrombocytopenia in intensive care unit. Meanwhile, antifungals and bacterial infection were associated with platelet counts less than 49/nL. Finally, platelet transfusion may be associated with reduced mortality in patients with platelet counts between 30 and 49/nL.

Clinical Implications of Thrombocytopenia at Cardiogenic Shock Presentation: Data from a Multicenter Registry

PURPOSE

Thrombocytopenia (platelet count <150×10³/μL) is associated with poor outcomes in various critical illness settings. However, the prognostic value of platelet count in patients with cardiogenic shock (CS) remains unclear.

MATERIALS AND METHODS

We enrolled 1202 patients between January 2014 and December 2018 from a multicenter retrospective-prospective cohort registry of CS. Clinical characteristics and treatment outcomes were compared between the patients with and without thrombocytopenia.

RESULTS

At presentation with CS, 244 (20.3%) patients had thrombocytopenia. The patients with thrombocytopenia had lower blood pressure, hemoglobin level, and worse liver and renal functions compared to the patients without. During hospitalization, the patients with thrombocytopenia had more frequent gastrointestinal bleeding (10.5% vs. 3.8%, p=0.009), sepsis (8.3% vs. 2.6%, p=0.013), requirement of renal replacement therapy (36.5% vs. 18.9%, p<0.001), requirement of mechanical ventilation (65.2% vs. 54.4%, p=0.003), longer intensive care unit stay (8 days vs. 4 days, p<0.001), and thirty-day mortality (40.2% vs. 28.5%, p<0.001) compared to those without. In addition, the platelet count was an independent predictor of 30-day mortality (per 10³/μL decrease; adjusted hazard ratio: 1.002, 95% confidence interval: 1.000-1.003, p=0.021).

CONCLUSION

Thrombocytopenia at CS presentation was associated with worse clinical findings, higher frequencies of complications, and longer stay at the intensive care unit. Also, thrombocytopenia was independently associated with increased 30-day mortality. (Clinical trial registration No. NCT02985008).

Thrombocytopenia and platelet course on hospital mortality in neurological intensive care unit: a retrospective observational study from large database

BACKGROUND

Thrombocytopenia (TP) has been shown to be an independent predictor of mortality in the intensive care unit (ICU) patients. Studies are lacking in the neurological ICU (NICU) population. The aim was to evaluate the incidence of TP in NICU and the relationship between TP and outcomes.

METHODS

We conducted a retrospective multicenter study of prospectively collected data of all patients admitted to the NICU between 2014 and 2015 from a large database (eICU Collaborative Research Database). The main exposure was TP at admission and TP developed during NICU stay. Multivariable logistic regression and Cox proportional hazard models were used to evaluate the relationship of TP at admission and platelet course with hospital mortality. The primary outcome was hospital mortality.

RESULTS

7450 patients in NICU from 17 hospitals were included. Hospital mortality was 9%. TP at admission was present in 20% of patients, TP developed during NICU stay was present in 13.2% of patients. TP at admission was not associated with hospital mortality after adjusting for confounders (OR 1.14 [95% CI 0.92-1.41, p = 0.237]). Hospital mortality of continuous TP during NICU stay was 15% while hospital mortality of recovery from TP at admission was 6% (p < 0.001). Patients with TP developed during NICU stay had higher odds ratio for hospital mortality (OR 1.65 [95% CI 1.3-2.09, p < 0.001]).

CONCLUSIONS

Thrombocytopenia is common in NICU and patients who have thrombocytopenia not resolving have increased mortality. Patients' recovery from thrombocytopenia may predict a good prognosis.

Effects of Baseline Thrombocytopenia and Platelet Decrease Following Renal Replacement Therapy Initiation in Patients With Severe Acute Kidney Injury

OBJECTIVES

Thrombocytopenia is common in critically ill patients with severe acute kidney injury and may be worsened by the use of renal replacement therapy. In this study, we evaluate the effects of renal replacement therapy on subsequent platelet values, the prognostic significance of a decrease in platelets, and potential risk factors for platelet decreases.

DESIGN

Post hoc analysis of the Acute Renal Failure Trial Network Study.

SETTING

The Acute Renal Failure Trial Network study was a multicenter, prospective, randomized, parallel-group trial of two strategies for renal replacement therapy in critically ill patients with acute kidney injury conducted between November 2003 and July 2007 at 27 Veterans Affairs and university-affiliated medical centers.

SUBJECTS

The Acute Renal Failure Trial Network study evaluated 1,124 patients with severe acute kidney injury requiring renal replacement therapy.

INTERVENTIONS

Predictor variables were thrombocytopenia at initiation of renal replacement therapy and platelet decrease following renal replacement therapy initiation.

MEASUREMENTS AND MAIN RESULTS

Outcomes were mortality at 28 days, 60 days, and 1 year, renal recovery, renal replacement therapy free days, ICU-free days, and hospital-free days. Baseline thrombocytopenia in patients requiring renal replacement therapy was associated with increased mortality and was also associated with lower rates of renal recovery. A decrease in platelet values following renal replacement therapy initiation was associated with increased mortality. Continuous renal replacement therapy was not an independent predictor of worsening thrombocytopenia compared with those treated with intermittent hemodialysis.

CONCLUSIONS

Baseline thrombocytopenia and platelet decrease following renal replacement therapy initiation were associated with increased mortality, and baseline thrombocytopenia was associated with decreased rates of renal recovery. Continuous renal replacement therapy did not decrease platelets compared with hemodialysis.

The Use of High Dose Eltrombopag in the Management of Sepsis-Associated Thrombocytopenia in Critically Ill Patients

Introduction

Sepsis is a life-threatening condition, and sepsis-associated thrombocytopenia (SAT) is a common consequence of the disease where platelet count falls drastically within a very short time. Multiple key factors may cause platelet over-activation, destruction and reduction in platelet production during the sepsis. Eltrombopag is a thrombopoietin receptor agonist and is the second-line drug of choice in the treatment of chronic immune thrombocytopenia (ITP).

Aim of the study

The objective of this study was to observe the therapeutic outcome of high dose eltrombopag in SAT management in critically ill patients.

Material and Methods

This 6-month-long single group, observational study was conducted on seventeen ICU patients with SAT. Eltrombopag 100 mg/day in two divided doses was given to each patient. Platelet counts were monitored. A low platelet blood count returning to 150 K/μL or above, is taken as indicative of a successful reversal of a thrombocytopenia event.

Results

The mean Apache II score of patients (n= 17) was 18.71 (p-value: >0.05). No eltrombopag-induced adverse event was observed among the patients during the study period. Thrombocytopenia events were reversed successfully in 64.71% of patients (11; n= 17) within eight days of eltrombopag therapy.

Conclusions

The therapeutic potentiality of high dose eltrombopag regime in the management of sepsis-associated thrombocytopenia was found clinically significant in over two-thirds of critically ill adult patients enrolled in the study. These data may point to a new strategy in the management of acute type of thrombocytopenia in septic patients.

Stress Ulcer Prophylaxis in Neurocritical Care

Stress ulcer prophylaxis (SUP) with acid-suppressive drug therapy is widely utilized in critically ill patients following neurologic injury for the prevention of clinically important stress-related gastrointestinal bleeding (CIB). Data supporting SUP, however, largely originates from studies conducted during an era where practices were vastly different than what is considered routine by today's standard. This is particularly true in neurocritical care patients. In fact, the routine provision of SUP has been challenged due to an increasing prevalence of adverse drug events with acid-suppressive therapy and the perception that CIB rates are sparse. This narrative review will discuss current controversies with SUP as they apply to neurocritical care patients. Specifically, the pathophysiology, prevalence, and risk factors for CIB along with the comparative efficacy, safety, and cost-effectiveness of acid-suppressive therapy will be described.

Thrombocytopenia in Septic Shock Patients—A Prospective Observational Study of Incidence, Risk Factors and Correlation with Clinical Outcome

The objectives of the study were to study the incidence of various degrees of severity of thrombocytopenia in septic shock, the risk factors for its development and the correlation with clinical outcome. Complete blood counts, chemistry panel, arterial lactate, serum cortisol, APACHE II score, logistic organ dysfunction score and SOFA score were determined in 69 septic shock patients within 24 hours of admission or onset of septic shock. We followed the patients until they died or for six months to determine the mortality rate. The incidence of thrombocytopenia in our study group was 55%. Patients with thrombocytopenia had significantly higher serum creatinine, SOFA score, vasopressor requirement, lower PaO2/FiO2 ratio and higher mortality than those without thrombocytopenia (P <0.05). Higher SOFA score, low PaO2/FiO2 ratio and high vasopressor dose were independent risk factors for development of thrombocytopenia. The presence of thrombocytopenia had significant correlation with SOFA score (P=0.008). On receiver-operator characteristic curve analysis, platelet count was found to be predictive of increased mortality (area under curve=0.56). Thrombocytopenic patients had 1.4 times the risk of mortality and lower survival probability at six months (log rank test P=0.03). In conclusion, thrombocytopenia is common in septic shock and is associated with worse clinical outcome. Higher SOFA score, low PaO2/FiO2 ratio and high vasopressor dose are independent risk factors for development of thrombocytopenia in septic shock.

Linezolid-induced thrombocytopenia increases mortality risk in intensive care unit patients, a 10 year retrospective study

WHAT IS KNOWN AND OBJECTIVE

Linezolid-induced thrombocytopenia is one of the many confounding conditions in critically ill patients. It is rare but prognostic importance of linezolid-induced thrombocytopenia in ICU population has not been well investigated. The study is to assess the incidence and risk factors of linezolid-induced thrombocytopenia in ICU patients.

METHODS

We conducted a retrospective study with ICU patients treated with linezolid between January 2005 and December 2015 at the adult medical, surgical, emergency, and neurological ICUs at 1500-bed tertiary university medical center.

RESULTS AND DISCUSSION

There were 60 patients (mean age: 69.8 ± 11.9), 29 (48.3%) who developed linezolid-induced thrombocytopenia determined by the Naranjo algorithm on a case-by-case basis during the study period. The patients with linezolid-induced thrombocytopenia had a higher rate of any malignancy (41.4% vs 9.7%, P = 0.007), elevated baseline creatinine levels (median [interquartile range; IQR]: 1.7 mg/dL [0.9-2.5] vs 0.9 mg/dL [0.6-1.3]; P = 0.042), and lower baseline platelet counts (median [IQR] 160 × 10⁹ /L [128-230] vs 194 × 10⁹ /L [118-285]; P = 0.296) than patients without linezolid-induced thrombocytopenia. The patients who developed thrombocytopenia received more platelet transfusions (34.5% vs 6.5%, P = 0.009) and had higher ICU mortality rates (62.1% vs 32.3%, P = 0.037). Logistic regression analysis revealed the following significant risk factors for linezolid-induced thrombocytopenia: presence of any malignancy (odds ratio; OR [95% confidence interval; CI]: 8.667 [1.986-37.831]) and an elevated baseline serum creatinine level (OR: 1.673, CI: 1.046-2.675]).

WHAT IS NEW AND CONCLUSION

Critically ill patients with any malignancy or an elevated baseline creatinine level who were treated with linezolid in the ICU were more likely to develop thrombocytopenia. More importantly, mortality increased with patients who developed linezolid-induced thrombocytopenia compared to those did not.

Risks of bleeding and thrombosis in intensive care unit patients with haematological malignancies

Background

Patients with malignant haematological disease and especially those who require intensive care have an increased risk of bleeding and thrombosis, but none of these data were obtained in ICU patients only. We assessed the incidence of bleeding and thrombotic complications, use of blood products and risk factors for bleeding in an adult population of ICU patients with haematological malignancies.

Methods

We screened all patients with acute leukaemia and myelodysplastic syndrome admitted to a university hospital ICU during 2008–2012. Bleeding in ICU was scored according to the WHO grading system, and risk factors were evaluated using unadjusted and adjusted analyses.

Results

In total, 116 of 129 ICU patients were included; their median length of stay was 7 (IQR 2–16) days. Of these, 66 patients (57%) had at least one bleeding episode in ICU; they bled for 3 (2–6) days and most often from lower and upper airways and upper GI tract. Thirty-nine (59%) of the 66 patients had severe or debilitating (WHO grade 3 or 4) bleeding. The median platelet count on the day of grade 3 or 4 bleeding was 23 × 10⁹ per litre (IQR 13–39). Nine patients (8%) died in ICU following a bleeding episode; five of these had intra-cerebral haemorrhage. Platelet count on admission was associated with subsequent bleeding (adjusted odds ratio 1.18 (95% CI 1.03–1.35) for every 10 × 10⁹ per litre drop in platelet count, p = 0.016). Eleven of the 116 patients (9%) developed a clinically significant thrombosis in ICU, which was the cause of death in four patients. The median platelet count was 20 × 10⁹ per litre (15–48) at the time of thrombosis. The patients received a median of 6 units of red blood cells, 1 unit of fresh frozen plasma and 8 units of platelet concentrates in ICU.

Conclusions

Severe and debilitating bleeding complications were frequent in our ICU patients with haematological malignancies, but thrombosis also occurred in spite of low platelet counts. Platelet count on ICU admission was associated with subsequent bleeding.

Electronic supplementary material

The online version of this article (10.1186/s13613-017-0341-y) contains supplementary material, which is available to authorized users.

Platelet Transfusions in Pediatric Intensive Care

OBJECTIVES

To characterize the determinants of platelet transfusion in a PICU and determine whether there exists an association between platelet transfusion and adverse outcomes.

DESIGN

Prospective observational single center study, combined with a self-administered survey.

SETTING

PICU of Sainte-Justine Hospital, a university-affiliated tertiary care institution.

PATIENTS

All children admitted to the PICU from April 2009 to April 2010.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

Among 842 consecutive PICU admissions, 60 patients (7.1%) received at least one platelet transfusion while in PICU. In the univariate analysis, significant determinants for platelet transfusion were admission Pediatric Risk of Mortality Score greater than 10 (odds ratio, 6.80; 95% CI, 2.5-18.3; p < 0.01) and Pediatric Logistic Organ Dysfunction scores greater than 20 (odds ratio, 26.9; 95% CI, 8.88-81.5; p < 0.01), history of malignancy (odds ratio, 5.08; 95% CI, 2.43-10.68; p < 0.01), thrombocytopenia (platelet count, < 50 × 10/L or < 50,000/mm) (odds ratio, 141; 95% CI, 50.4-394.5; p < 0.01), use of heparin (odds ratio, 3.03; 95% CI, 1.40-6.37; p < 0.01), shock (odds ratio, 5.73; 95% CI, 2.85-11.5; p < 0.01), and multiple organ dysfunction syndrome (odds ratio, 10.41; 95% CI, 5.89-10.40; p < 0.01). In the multivariate analysis, platelet count less than 50 × 10/L (odds ratio, 138; 95% CI, 42.6-449; p < 0.01) and age less than 12 months (odds ratio, 3.06; 95% CI, 1.03-9.10; p = 0.02) remained statistically significant determinants. The attending physicians were asked why they gave a platelet transfusion; the most frequent justification was prophylactic platelet transfusion in presence of thrombocytopenia with an average pretransfusion platelet count of 32 ± 27 × 10/L (median, 21), followed by active bleeding with an average pretransfusion platelet count of 76 ± 39 × 10/L (median, 72). Platelet transfusions were associated with the subsequent development of multiple organ dysfunction syndrome (odds ratio, 2.53; 95% CI, 1.18-5.43; p = 0.03) and mortality (odds ratio, 10.1; 95% CI, 4.48-22.7; p < 0.01).

CONCLUSIONS

Among children, 7.1% received at least one platelet transfusion while in PICU. Thrombocytopenia and active bleeding were significant determinants of platelet transfusion. Platelet transfusions were associated with the development of multiple organ dysfunction syndrome and increased mortality.

Thrombocytopenia is associated with a dysregulated host response in critically ill sepsis patients

Preclinical studies have suggested that platelets influence the host response during sepsis. We sought to assess the association of admission thrombocytopenia with the presentation, outcome, and host response in patients with sepsis. Nine hundred thirty-one consecutive sepsis patients were stratified according to platelet counts (very low <50 × 10(9)/L, intermediate-low 50 × 10(9) to 99 × 10(9)/L, low 100 × 10(9) to 149 × 10(9)/L, or normal 150 × 10(9) to 399 × 10(9)/L) on admission to the intensive care unit. Sepsis patients with platelet counts <50 × 10(9)/L and 50 × 10(9) to 99 × 10(9)/L presented with higher Acute Physiology and Chronic Health Evaluation scores and more shock. Both levels of thrombocytopenia were independently associated with increased 30-day mortality (hazard ratios with 95% confidence intervals 2.00 [1.32-3.05] and 1.72 [1.22-2.44], respectively). To account for baseline differences besides platelet counts, propensity matching was performed, after which the association between thrombocytopenia and the host response was tested, as evaluated by measuring 17 plasma biomarkers indicative of activation and/or dysregulation of pathways implicated in sepsis pathogenesis and by whole genome blood leukocyte expression profiling. In the propensity matched cohort, platelet counts < 50 × 10(9)/L were associated with increased cytokine levels and enhanced endothelial cell activation. All thrombocytopenic groups showed evidence of impaired vascular integrity, whereas coagulation activation was similar between groups. Blood microarray analysis revealed a distinct gene expression pattern in sepsis patients with <50 × 10(9)/L platelets, showing reduced signaling in leukocyte adhesion and diapedesis and increased complement signaling. These data show that admission thrombocytopenia is associated with enhanced mortality and a more disturbed host response during sepsis independent of disease severity, thereby providing clinical validity to animal studies on the role of platelets in severe infection.

The evaluation of abdominal findings in Crimean-Congo hemorrhagic fever

OBJECTIVE

Crimean-Congo hemorrhagic fever (CCHF) is a widely seen, fatal disease and is endemic to some countries. It affects many organs in the abdomen. Comprehensive radiological study of CCHF is quite rare. This study will use multiple detector computed tomography (MDCT) to investigate if there is a relationship between clinical laboratory measurements and abdominal findings in CCHF and discuss our findings in the light of the literature.

MATERIALS AND METHODS

We retrospectively evaluated the medical records of 443 patients diagnosed with CCHF in our hospital between April 1, 2008 and September 30, 2014. Fifty-one patients had undergone abdominal MDCT examination.

RESULTS

The most common findings seen in abdominal MDCT were intra-abdominal free fluid and hepatomegaly. Gallbladder wall thickening, heterogeneity in mesenteric, omental fatty tissue, and splenomegaly were other common findings. Subcutaneous fat tissue edema, intramuscular hemorrhage, duodenal wall thickening, colon wall thickening, pancreatitis, and acute renal failure were among the rare findings seen in abdominal MDCT. Comparison of these findings to the clinical laboratory parameters showed a strong relationship between intra-abdominal free fluid and platelet count.

CONCLUSION

Our study is the first comprehensive study on abdominal MDCT findings of CCHF. We detected a strong relationship between patients' platelet count and abdominal free liquid. Therefore, it should be kept in mind that abdominal free fluid can be among clinical manifestations in patients with platelet counts ≤50000 and that this manifestation can become aggravated.

Drug-Induced Thrombocytopenia in the Critically Ill

Background:Drugs are suspected when obvious causes of intensive care unit (ICU)-acquired thrombocytopenia have been excluded. It has been estimated that 10% to 25% of cases may be drug induced. Objectives: The objectives of this study were to evaluate the risk of thrombocytopenia associated with drug classes commonly used in the ICU. Methods: Data concerning patients admitted for more than 48 hours between 1997 and 2011 were extracted from a research-purpose database. Patients with thrombocytopenia within the first 72 hours of admission and with diagnoses or interventions considered strongly associated with thrombocytopenia were excluded. Drug exposures were compared and adjusted for confounders using conditional logistic regression. Results: A total of 238 cases were identified after exclusions. Each case was matched according to sex, age, admission year, and admission unit with 1 control. In univariate analysis, quinolones (odds ratio [OR] = 1.56; 95% CI = 1.01-2.40) and extended spectrum β-lactams (OR = 1.71; 95% CI = 1.00-2.93) were significantly associated with an increased risk of thrombocytopenia. After adjusting for confounders, exposure to quinolones was the only drug class with a statistically significant increase in risk of thrombocytopenia (OR = 1.697; 95% CI = 1.002-2.873; P = 0.049). Conclusion: In this study of ICU-acquired thrombocytopenia, we found no association between the exposures to several antibiotic classes, anticonvulsants, antiplatelet agents, nonsteroidal anti-inflammatory agents, and heparins and thrombocytopenia. As linezolid was not studied, no conclusions can be drawn concerning this agent. The statistically significant association between quinolones and thrombocytopenia warrants further investigation.

Thrombocytopenia in critically ill patients receiving thromboprophylaxis: frequency, risk factors, and outcomes

BACKGROUND

Thrombocytopenia is the most common hemostatic disorder in critically ill patients. The objective of this study was to describe the incidence, risk factors, and outcomes of thrombocytopenia in patients admitted to medical-surgical ICUs.

METHODS

Three thousand seven hundred forty-six patients in 67 centers were enrolled in a randomized trial in which unfractionated heparin was compared with low-molecular-weight heparin (LMWH) for thromboprophylaxis. Patients who had baseline platelet counts < 75 × 10(9)/L or severe coagulopathy at screening were excluded. We analyzed the risk of developing mild (100-149 × 10(9)/L), moderate (50-99 × 10(9)/L), and severe (< 50 × 109/L) thrombocytopenia during an ICU stay. We also assessed independent and time-varying predictors of thrombocytopenia and the effect of thrombocytopenia on major bleeding, transfusions, and death.

RESULTS

The incidences of mild, moderate, and severe thrombocytopenia were 15.3%, 5.1%, and 1.6%, respectively. The predictors of each category of thrombocytopenia were APACHE (Acute Physiology and Chronic Health Evaluation) II score, use of inotropes or vasopressors, and renal replacement therapy. The risk of moderate thrombocytopenia was lower in patients who received LMWH thromboprophylaxis but higher in surgical patients and in patients who had liver disease. Each category of thrombocytopenia was associated with subsequent bleeding and transfusions. Moderate and severe thrombocytopenia were associated with increased ICU and hospital mortality.

CONCLUSION

A high severity of illness, prior surgery, use of inotropes or vasopressors, renal replacement therapy, and liver dysfunction are associated with a higher risk of thrombocytopenia developing in the ICU, whereas LMWH thromboprophylaxis is associated with a lower risk. Patients who develop thrombocytopenia in the ICU are more likely to bleed, receive transfusions, and die.

Thrombocytopenia in adult patients with sepsis: incidence, risk factors, and its association with clinical outcome

Background

Sepsis is a major risk factor for the development of thrombocytopenia, but few studies have specifically evaluated prognostic importance of thrombocytopenia in patients with sepsis. We investigated the incidence, risk factors, and prognostic importance of thrombocytopenia in adult patients admitted to the intensive care unit (ICU) with sepsis.

Methods

A retrospective analysis of patients admitted with severe sepsis/septic shock from December 2007 to January 2009 to a 24-bed medical ICU was done.

Results

A total of 304 patients were included in the study. The patients' mean (±SD) age was 68.8 (±15.8) years. The majority (93.7%) had septic shock, and pneumonia was the most common infection (38.8%). Thrombocytopenia developed in 145 patients (47.6%): 77 (25.3%) at ICU admission and 68 (22.3%) during their hospital course. The median (IQR) duration of thrombocytopenia was 4.4 (1.9–6.9) days. Patients who developed thrombocytopenia had more episodes of major bleeding (14.4% vs. 3.7%, P < 0.01) and received more transfusions. Patients with thrombocytopenia had a higher incidence of acute kidney injury (44.1% vs. 29.5%, P < 0.01), prolonged vasopressor support (median (IQR): 37 (17–76) vs. 23 (13–46) h, P < 0.01), and longer ICU stay (median (IQR): 3.1 (1.6–7.8) vs. 2.1 (1.2–4.4) days, P < 0.01). The 28-day mortality was similar between patients with and without thrombocytopenia (32.4% vs. 24.5%, P = 0.12). However, while 15 of 86 patients (17.4%) who resolved their thrombocytopenia died, 32 of 59 patients (54.2%) whose thrombocytopenia did not resolve died (P < 0.01). The association between non-resolution of thrombocytopenia and mortality remained significant after adjusting for age, APACHE III score and compliance with a sepsis resuscitation bundle (P < 0.01).

Conclusions

Thrombocytopenia is common in patients who are admitted to the ICU with severe sepsis and septic shock. Patients with thrombocytopenia had more episodes of major bleeding, increased incidence of acute kidney injury, and prolonged ICU stay. Non-resolution of thrombocytopenia, but not thrombocytopenia itself, was associated with increased 28-day mortality.

Comparative evaluation of thrombocytopenia in adult patients receiving linezolid or glycopeptides in a respiratory intensive care unit

Linezolid is an oxazolidinone antibiotic agent, active against gram-positive bacteria that are resistant to traditional antibiotics, including glycopeptides. Linezolid is generally well tolerated, but has been associated with hematologic adverse effects such as thrombocytopenia. The primary objective of this study was to compare the incidence of thrombocytopenia between patients receiving linezolid or glycopeptides in different age groups. The secondary objective was to assess the association between the time-to-event and occurrence of thrombocytopenia. This retrospective study reviewed the medical records of patients who were treated with linezolid or glycopeptides (vancomycin or teicoplanin) between January 2010 and June 2013 in a respiratory intensive care unit. Data were extracted from the patients' electronic medical records, which were obtained from a central database in the hospital, and multivariate analyses were performed. In total, the study included 225 patients who received linezolid or glycopeptides. The cumulative probability of thrombocytopenia was higher in the patients receiving linezolid than in those receiving glycopeptides (P<0.05), however the cumulative probability of thrombocytopenia did not differ significantly between patients receiving linezolid or glycopeptides in the subgroup whose age was <65 years (P>0.05). With a treatment duration of ≥7 days, the incidence of thrombocytopenia and the mean platelet count reduction in the patients receiving linezolid was significantly higher than in those receiving glycopeptides (P<0.05). No significant difference was identified in the mean platelet counts between the patients receiving linezolid and those receiving glycopeptides. In conclusion, it was identified that patients in a respiratory intensive care unit, aged ≥65 years or with a treatment duration of ≥7 days who were treated with linezolid were more likely to develop thrombocytopenia than patients of the same subgroup who were treated with glycopeptides.

Risk factors and impact of major bleeding in critically ill patients receiving heparin thromboprophylaxis

PURPOSE

Bleeding frequently complicates critical illness and may have serious consequences. Our objectives are to describe the predictors of major bleeding and the association between bleeding and mortality in medical-surgical critically ill patients receiving heparin thromboprophylaxis.

METHODS

We prospectively studied patients from 67 intensive care units and six countries enrolled in a thromboprophylaxis trial (NCT00182143) comparing dalteparin with unfractionated heparin. Patients with trauma, orthopedic surgery or neurosurgery were excluded. Trained research coordinators used a validated tool to document bleeding, which underwent duplicate independent blinded adjudication. Major bleeding was defined as hypovolemic shock, bleeding into critical sites, requiring an invasive intervention or transfusion of at least two units of red blood cells, or associated with hypotension or tachycardia in the absence of other causes. Adjusted Cox proportional hazard regression analysis was used to identify major bleeding predictors and the association between bleeding and mortality.

RESULTS

Among 3,746 patients, bleeding occurred in 208 [5.6 %, 95 % confidence interval (CI) 4.9-6.3 %]. Time-dependent predictors were prolonged activated partial thromboplastin time [hazard ratio (HR) 1.10, 1.05-1.14 per 10 s increase], lower platelet count (HR 1.16, 1.09-1.24 per 50 × 10(9)/L decrease), therapeutic heparin (HR 3.26, 1.72-6.17), antiplatelet agents (HR 1.38, 1.02-1.88), renal replacement therapy (HR 1.75, 1.20-2.56), and recent surgery (HR 1.64, 1.01-2.65). Type of pharmacologic thromboprophylaxis was not associated with bleeding. Patients with bleeding had a higher risk of in-hospital death (HR 2.09, 1.69-2.57).

CONCLUSIONS

As major bleeding has modifiable risk factors and is associated with in-hospital mortality, strategies to mitigate these factors should be evaluated in critically ill patients.

The incidence, causes, and prognostic significance of new-onset thrombocytopenia in intensive care units: a prospective cohort study in a Korean hospital

This study was designed to investigate the incidence, causes, and outcomes of new-onset thrombocytopenia (NOT) in Korean intensive care units (ICUs). A prospective cohort study was conducted in medical ICUs of Samsung Medical Center between August 2010 and February 2011. All newly admitted patients were included if they stayed in the ICU for more than 48 hr and did not have thrombocytopenia upon admission. A total of 186 patients were included. NOT developed in 37.1%. Most common cause of NOT was sepsis with disseminated intravascular coagulation (66.7%), followed by drug-induced thrombocytopenia (18.8%), and heparin-induced thrombocytopenia (2.9%). IgG-specific antibody to platelet factor 4/heparin was positive in 2.4% among patients treated with heparin, and thrombosis occurred in two patients. Twenty eight-day mortality was higher in patients that developed NOT compared to those that did not develop NOT (39.1% vs 12%, P < 0.001). NOT increased the odds ratio of 28-day mortality and was an independent risk factor for mortality (OR 3.52; 95% CI 1.32-9.38; P = 0.012). In conclusion, NOT is common and is an independent risk factor for mortality in Korean ICU patients. Therefore, clinicians should make every effort to correct the causes of NOT.

Etiology and significance of thrombocytopenia in critically ill patients

Thrombocytopenia is common in critically ill patients and increases morbidity and mortality. A diagnosis of heparin-induced thrombocytopenia (HIT) is frequently considered in any ICU patient who develops thrombocytopenia in the context of ongoing heparin exposure. As the usual tests to diagnose HIT are often neither specific nor sensitive enough to be confirmatory, the intensivist must largely rely on clinical judgment in treatment decisions. Patients in the ICU may also develop thrombocytopenia resulting from non-HIT immune mechanisms, nonimmune platelet consumption, and from decreased platelet production due to preexisting disorders or as a result of their critical illness and/or drug therapy.

Assessment of the 4Ts pretest clinical scoring system as a predictor of heparin-induced thrombocytopenia

STUDY OBJECTIVE

To evaluate the utility of the 4Ts clinical scoring system as a pretest probability method for the detection of heparin-induced thrombocytopenia (HIT).

DESIGN

Prospective observational study.

SETTING

Medical and surgical inpatients at a tertiary care medical center.

PATIENTS

Eighty consecutive patients with suspicion of HIT who had a polyspecific enzyme-linked immunosorbent assay (ELISA) performed between December 1, 2008, and April 1, 2009, for detection of platelet factor 4 (PF4)-heparin antibodies.

MEASUREMENTS AND MAIN RESULTS

The predictive value of the 4Ts scoring system as determined by using a standard laboratory marker of HIT--the ELISA--and the interrater reliability of the scoring system were assessed. Sixty-seven (84%) of the 80 patients had low clinical probability of HIT based on the calculated 4Ts score. The ELISA result was negative for PF4-heparin antibodies in 74 patients (93%). Based on the results of the ELISA, the negative predictive value of the 4Ts score was 91%. Each 4Ts score was calculated by two independent investigators and adjudicated by a third investigator when necessary. The interrater reliability of the scoring system was fair (Cohen κ coefficient 0.362, 95% confidence interval [CI] 0.222-0.502; weighted κ coefficient 0.554 (95% CI 0.441-0.667). Determination of the timing of HIT was associated with the largest number of discrepancies (16) between evaluators, followed by other causes of thrombocytopenia (15), degree of decline in platelet count (14), and the presence of thrombosis or other sequelae (2).

CONCLUSION

A low 4Ts score supports a low probability of HIT based on the results of the polyspecific ELISA. Overall, the interrater reliability of the scoring system was fair. Components of the 4Ts scoring system need to be further clarified or modified in order to improve interrater reliability and thereby increase the clinical utility of this pretest probability model.

Mitral valve repair in a patient with thrombocytopenia-absent radius syndrome: case report

Thrombocyte level and functions are vital factors during cardiac surgery. Thrombocytopenia-absent radius syndrome (TAR) is a rare genetic disorder consisting of skeletal abnormalities and thrombocytopenia. In this report, we present the management strategy for a 23-year-old female patient with TAR syndrome who underwent mitral valve repair.

Thrombocytopenia in the intensive care unit patient

The many comorbidities in the severely ill patient also make thrombocytopenia very common (∼40%) in intensive care unit patients. The risk of bleeding is high with severe thrombocytopenia and is enhanced in intensive care patients with mild or moderately low platelet counts when additional factors are present that interfere with normal hemostatic mechanisms (eg, platelet function defects, hyperfibrinolysis, invasive procedures, or catheters). Even if not associated with bleeding, low platelet counts often influence patient management and may prompt physicians to withhold or delay necessary invasive interventions, reduce the intensity of anticoagulation, order prophylactic platelet transfusion, or change anticoagulants due to fear of heparin-induced thrombocytopenia. One approach to identify potential causes of thrombocytopenia that require specific interventions is to consider the dynamics of platelet count changes. The relative decrease in platelet counts within the first 3 to 4 days after major surgery is informative about the magnitude of the trauma or blood loss, whereas the dynamic of the platelet count course thereafter shows whether or not the physiologic compensatory mechanisms are working. A slow and gradual fall in platelet counts developing over 5 to 7 days is more likely to be caused by consumptive coagulopathy or bone marrow failure, whereas any abrupt decrease (within 1-2 days) in platelet counts manifesting after an initial increase in platelet counts approximately 1 to 2 weeks after surgery strongly suggests immunologic causes, including heparin-induced thrombocytopenia, other drug-induced immune thrombocytopenia, and posttransfusion purpura.

Coagulopathy in critically ill patients: part 1: platelet disorders

Abnormalities of platelet number and function are the most common coagulation disorders seen among ICU patients. This article reviews the most frequent causes of thrombocytopenia by providing an overview of the following most common mechanisms: impaired production; sequestration; dilution; and destruction. Guidelines for treating thrombocytopenia and platelet dysfunction are also provided.

Drug-induced thrombocytopenia

Drug-induced thrombocytopenia (DIT) is a relatively common clinical disorder. It is imperative to provide rapid identification and removal of the offending agent before clinically significant bleeding or, in the case of heparin, thrombosis occurs. DIT can be distinguished from idiopathic thrombocytopenic purpura, a bleeding disorder caused by thrombocytopenia not associated with a systemic disease, based on the history of drug ingestion or injection and laboratory findings. DIT disorders can be a consequence of decreased platelet production (bone marrow suppression) or accelerated platelet destruction (especially immune-mediated destruction).

La thrombopénie en réanimation chirurgicale: incidence, analyse des facteurs de risque et impact sur le pronostic

OBJECTIVE

To determine the incidence of thrombocytopenia in a surgical intensive care unit (ICU), the risk factors associated with it, and its effect on patient outcome.

METHODS

During a 6-month period, all patients admitted to the surgical intensive care unit were studied prospectively. The factors associated with thrombocytopenia were evaluated by univariate and multivariate analysis.

RESULTS

The study included 112 patients with a mean age of 50+/-18 years and a mean SAPS II (Simplified Acute Physiology Score) of 25+/-19: 41 developed thrombocytopenia (incidence=36,6%). Risk factors associated with it in the univariate analysis were high SAPS II, high organ dysfunction score, invasive intravascular catheters, sepsis, septic shock, and bleeding. After multivariate logistic regression analysis, only 3 independent risk factors remained for thrombocytopenia: bleeding (OR=11.9; 95% CI: 3.3-43.6; p<0.001), sepsis (OR=4.1; 95% CI: 1.3-11.7; p=0.013) and SAPS II>20 (OR=2.8; 95% CI: 1.0-7.8; p=0.042). Although mortality was higher in patients with than without thrombocytopenia , this difference was not statistically significant (41% versus 31%, p=0.26). Survival was similar in both groups, according to the Kaplan-Meier survival curve.

CONCLUSION

Thrombocytopenia is common in surgical ICUs. Bleeding and sepsis are the major risk factors. In this study, thrombocytopenia was not an independent factor of poor vital outcome in these critically ill patients.

Utilization of platelet transfusions in the intensive care unit: indications, transfusion triggers, and platelet count responses

BACKGROUND

A description of current platelet (PLT) transfusion practice in the intensive care unit (ICU) is needed.

STUDY DESIGN AND METHODS

All thrombocytopenic patients (PLT count, <150 x 10(9)/L) who received PLT transfusions were identified from a previous prospective study of consecutive medical-surgical ICU patients; trauma, orthopedic, and cardiac surgery were exclusions. Risk factors for ineffective transfusions were examined.

RESULTS

Of 261 ICU patients, 118 (45.2%) had thrombocytopenia and a PLT count nadir of less than 50 x 10(9) per L (n = 22), 50 to 99 x 10(9) per L (n = 37), and 100 to 149 x 10(9) per L (n = 59). Twenty-seven (22.9%) patients received PLT transfusions (n = 76 transfusions) and 37 (31.4%) had major bleeding. PLT dose was approximately 3 to 4 x 10(11) per L transfusion. Therapeutic (n = 24) and prophylactic (n = 52) PLT transfusion triggers were 51 x 10(9) per L (interquartile range [IQR], 26 to 68) and 41 x 10(9) per L (IQR, 20 to 57), respectively, as measured at a median of 4.5 hours (IQR, <1.6 to 6.9) before transfusion. A single PLT transfusion resulted in a median PLT increase of 14 x 10(9) per L (IQR, -2 to 30) measured at 5.2 hours (IQR, 1.8 to 8.8) after the transfusion; however, no PLT count increase was observed after 17 transfusions given to 13 (48.1%) patients. No risk factors for ineffective transfusions were identified.

CONCLUSIONS

Among critically ill patients, most PLT transfusions were administered to prevent, rather than to treat, bleeding, with a transfusion trigger of 40 to 50 x 10(9) per L. Nearly half of ICU patients who received transfusions failed to mount a PLT count increase after a single transfusion. Prospective studies are needed to determine the effects of PLT transfusions on bleeding and predictors of ineffective transfusions in the ICU.

Thrombocytopenia in medical-surgical critically ill patients: prevalence, incidence, and risk factors

OBJECTIVE

The purpose of this study is to describe the prevalence, to analyze the incidence and independent risk factors for thrombocytopenia, and to examine the impact of thrombocytopenia developing in the intensive care unit (ICU) on patient outcome in a well-defined cohort of critically ill patients in a medical-surgical ICU.

MATERIALS AND METHODS

As part of a prospective cohort study examining the frequency and clinical importance of venous thromboembolism in the ICU, we enrolled consecutive patients older than 18 years expected to be in the ICU for more than 72 hours. Exclusion criteria were an admitting diagnosis of trauma, orthopedic surgery or cardiac surgery, pregnancy, and life support withdrawal. Patients had platelet counts performed as directed by clinical need. We defined thrombocytopenia as a platelet count of less than 150 x 10(9)/L and severe thrombocytopenia as a platelet count of less than 50 x 10(9)/L. Protocol-directed care included routine thromboprophylaxis and twice weekly screening ultrasonography of the legs. Patients were followed to hospital discharge.

RESULTS

Of the 261 enrolled patients, 121 (46%, 95% confidence interval [CI], 40%-53%) had thrombocytopenia (62 on ICU admission and 59 acquired during their ICU stay). Patients who developed a platelet count less than 150 x 10(9)/L during their ICU stay had higher ICU and hospital mortality (P = .03 and .005, respectively), required longer mechanical ventilation (P = .05), and were more likely to receive platelets (P < .001), fresh frozen plasma (P = .005), and red blood cell transfusions (P = .004) than patients who did not develop thrombocytopenia. The only independent risk factors for thrombocytopenia developing during the ICU stay were administration of nonsteroidal anti-inflammatory drugs before ICU admission (hazard ratio, 2.8; 95% CI, 1.3-6.0) and dialysis during the ICU stay (hazard ratio, 3.1; 95% CI, 1.2-7.8). Of the 33 patients who underwent 36 tests for heparin-induced thrombocytopenia, none tested positive.

CONCLUSIONS

We found that about 50% of the patients admitted to the ICU had at least one platelet count of less than 150 x 10(9)/L during their ICU stay. Patients who developed thrombocytopenia were more likely to die, required longer duration of mechanical ventilation, and were more likely to require blood product transfusion. Heparin-induced thrombocytopenia was frequently suspected but did not develop in these critically ill patients.

Heparin, Low Molecular Weight Heparin, and Heparin-Induced Thrombocytopenia in the ICU

Thrombocytopenia is common in critically ill patients who receive heparin. However, heparin-induced thrombocytopenia (HIT) is a relatively uncommon explanation for thrombocytopenia in this patient population. This article describes clinical features of HIT and interpretation of laboratory tests for HIT antibodies from the perspective of the intensive care unit.

Linezolid does not increase the risk of thrombocytopenia in patients with nosocomial pneumonia: comparative analysis of linezolid and vancomycin use

Reports from uncontrolled studies suggest that linezolid is associated with rates of thrombocytopenia higher than those reported in clinical studies. We assessed the risk of thrombocytopenia in 686 patients with nosocomial pneumonia who received linezolid or vancomycin for > or =5 days in 2 randomized, double-blind studies and for whom follow-up platelet counts had been measured. New-onset thrombocytopenia (platelet count of <150x10(9) platelets/L) occurred in 19 (6.4%) of 295 linezolid recipients and 22 (7.7%) of 285 vancomycin recipients with baseline platelet counts of > or =150x10(9) platelets/L; severe thrombocytopenia (platelet count of <50x10(9) platelets/L) occurred in only 1 patient in each group. Platelet counts decreased to less than the baseline level in 4 (6.6%) of 61 linezolid recipients and 5 (11.1%) of 45 vancomycin recipients who had baseline counts of <150x10(9) platelets/L. No patient had a decrease to <20x10(9) platelets/L. There were no statistically significant differences between groups in these or any other platelet assessments. Clinically significant thrombocytopenia was uncommon in our analysis, and linezolid was not associated with a greater risk of thrombocytopenia in seriously ill patients than was vancomycin.

Frequency of heparin-induced thrombocytopenia in critical care patients

The diagnosis of heparin-induced thrombocytopenia (HIT) in critically ill patients is complicated by lack of information on the frequency of HIT relative to thrombocytopenia from other causes. In addition, results from HIT diagnostic tests have not been clearly evaluated for clinical utility. In this prospective study, we estimated the frequency of HIT and the predictive performance of the heparin-platelet factor 4 enzyme-linked immunosorbent assay (heparin-PF4 ELISA) in 748 consecutive, heparin-treated patients in a combined intensive and coronary care unit. The criteria for diagnosis were as follows: two or more consecutive platelet counts below 150 x 10(3)/mm3 or a 33% or greater decrease in platelet count 5 or more days after beginning heparin, or any time after starting heparin for patients exposed to the agent within the previous 8 weeks; and a positive 14C-serotonin release assay (SRA), the reference standard. Specificity and predictive values for the heparin-PF4 ELISA were estimated in patients who met the clinical criteria for HIT. Of 748 patients, 267 were exposed to heparin for a sufficient length of time to be considered to be at risk for HIT. Forty of these patients (15.0%, 95% confidence interval [CI] 10.7%-19.3%) met the clinical criteria for HIT. Serum samples were available for 32 of these patients, one of whom tested positive by the SRA, yielding a HIT frequency of 0.39% (95% CI 0.01-2.1%). The specificity of the heparin-PF4 ELISA among thrombocytopenic patients with negative SRA results was 71%, and the positive (PPV) and negative (NPV) predictive values of this test were estimated to be 10% and 100%, respectively. The point estimate of the frequency of HIT in critically ill patients was less than 1% in this cohort. The low PPV and high NPV of the heparin-PF4 ELISA suggest that it can be used to exclude HIT as a cause of thrombocytopenia in this patient population.