Thrombocytopenia in intensive care patients: a comprehensive analysis of risk factors in 314 patients

Calcium Channel Blocker-Induced Thrombocytopenia in the Intensive Care Unit: A Rare Presentation and Review of the Literature

Patients with thrombocytopenia may report easy bruising, abnormal bleeding, and fatigue. Drug-induced thrombocytopenia has been reported with a variety of medications, most commonly heparin products, sulphonamides, carbamazepine, nonsteroidal anti-inflammatory drugs, anti-epileptic drugs, and chemotherapy. We present the case of a 58-year-old female with severe thrombocytopenia attributed to a calcium channel blocker (CCB) overdose, a very rare cause of thrombocytopenia. We discuss the diagnostic work-up and management in the intensive care unit and perform a literature review.

Cefepime: a novel cause of thrombocytopaenia

Thrombocytopaenia is a commonly encountered finding in hospitalised patients. Many antibiotics, especially beta-lactams, are well known to cause thrombocytopaenia by an immune-mediated mechanism. We present a 55-year-old woman who was admitted to the hospital with a complicated urinary tract infection resulting in right-sided pyonephrosis and pararenal abscess. She was observed to develop thrombocytopaenia after initiation of cefepime therapy. Following an extensive work-up for her new-onset thrombocytopaenia, she was diagnosed as a case of a drug (cefepime)-induced thrombocytopaenia. Her platelet count recovered back to normal levels after cessation of cefepime therapy. Based on our PubMed search, there are only a few cases of cefepime-induced thrombocytopaenia published in the literature. This paper illustrates that physicians should include cefepime among the possible aetiologies of thrombocytopaenia. Additionally, this article outlines the currently available approaches to the diagnosis and management of drug-induced thrombocytopaenia.

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.

Clinical Predictors of Morbidity and Mortality in Hospitalized Pediatric Patients With Ascites

OBJECTIVES

Ascites is a pathologic buildup of fluid in the peritoneal cavity. Knowledge is lacking in clinical outcome in pediatric patients with ascites. We aim to identify and assess clinical variables, associated with morbidity and mortality in pediatric patients who are hospitalized with ascites.

METHODS

A retrospective cohort study was performed on patients ages 0 to 21 hospitalized at Johns Hopkins Hospital between 1983 and 2010 with an ICD-9 discharge diagnosis of ascites (789.5, 789.51, 789.59). A total of 518 pediatric patients were studied, all with a diagnosis of ascites during hospitalization. Study outcomes included hospital length of stay (LOS) as a proxy for morbidity and death at hospital discharge for mortality. Variables analyzed included demographic data, ascites etiology and grade, comorbidities, and laboratory markers. Variables were analyzed by log-linear regression and competing risk model.

RESULTS

Among the 3 age groups (0-5, 6-12, and 13-21), the 0 to 5 age group experienced significantly increased LOS (P < 0.001) and mortality (P = 0.027). Ascites etiology of veno-occlusive disease (VOD) and the presence of hydrothorax or thrombocytopenia was also significantly associated with increased LOS. Ascites with the etiology of congestive hepatopathy and the presence of grade 3 ascites, hepatic encephalopathy, hepatorenal syndrome, hydrothorax, hyponatremia, and thrombocytopenia were associated with increased mortality. Additionally, black pediatric patients have an increased risk of mortality (P = 0.027). Other factors including sex, leukopenia, portal vein thrombosis, and splenomegaly were not associated with LOS or mortality.

CONCLUSIONS

Morbidity and mortality in pediatric patients hospitalized with ascites are associated with specific demographic and clinical factors. Further studies are required to apply this knowledge to predict the clinical outcomes.

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 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.

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.

Relation between dynamic changes of platelet counts and 30-day mortality in severely burned patients

Thrombocytopenia is a common event in severely burned patients and associated with adverse outcome. The underlying relationship between the dynamic changes of platelet counts and mortality has not been well defined. We performed a 6-year retrospective chart of adult patients with a burn index of 50 or greater admitted to two burn centers and collected data on patient demographics, laboratory results, and patient outcomes. The mean daily increase in the platelet count (∆PC/∆t) from day 3 to day 10 was calculated, and 30-day mortality was determined. For the study, 141 survivors and 65 nonsurvivors were enrolled. The sequential changes in PCs presented a biphasic pattern after admission, with a slump to the nadir during the first 3 days and a subsequent recovery. With respect to 30-day mortality, compared with the AUC of APACHE-Ⅱ score (0.841), no significant difference was noted between ΔPC/ΔT and APACHE-Ⅱ score (p = 0.0648). The ΔPC/ΔT associated with the best discrimination between survivors and nonsurvivors was 20.57 × 10⁹/L due to the cutoff with optimal Youden index (0.453). By multiple logistic regression, ΔPC/ΔT ＜ 20.57 × 10⁹/L was one of the prognostic predictors of 30-day mortality. Furthermore, Kaplan-Meier estimates of hospital survival according to the size of ΔPC/ΔT revealed that a blunted increase with ΔPC/ΔT ＜ 20.57 × 10⁹/L was associated with increased 30-day mortality. A blunted daily increase in PCs, especially ΔPC/ΔT < 20.57 × 10⁹/L, is associated with increased 30-day mortality, which provides prognostic information for mortality risk assessment in severely burned patients.

Vancomycin-Induced Thrombocytopenia: A Narrative Review

Thrombocytopenia has been reported as an adverse reaction of numerous drugs. Vancomycin is often overlooked as a culprit but has been associated with several cases of thrombocytopenia that were not well described in the literature. A literature search was conducted to find reports of thrombocytopenia induced by vancomycin. Biomedical databases including 'PubMed', 'Scopus', and 'Web of Science' were searched using terms 'vancomycin', 'platelet', 'pancytopenia', 'thrombocytopenia', and 'bleeding'. English language articles published before July 2015 were included. Thirty-nine papers including 29 case reports (30 cases), five observational studies, two clinical trials, two letters, and one case series remained for final analysis. The main route of administration was intravenous infusion. This adverse reaction seems to be duration dependent with the mean time to platelet nadir count of 8 days in reported cases. The interval may be significantly shorter in re-exposure to the drug. Platelet nadir counts ranged from 2000 to 100,000/mL in patients who experienced bleeding. Vancomycin-specific antibodies were detected in 13 of 17 patients who were tested in the case reports. Based on the Naranjo Adverse Drug Reaction Probability Scale, reaction was 'definite', 'probable', and 'possible' in 1, 15, and 14 patients, respectively. Among 30 cases, vancomycin was discontinued in 29 patients and platelets returned to normal counts within 5-6 days in 17 of them; in one patient, vancomycin was not discontinued, but platelet count recovered 11 days after the nadir time. Transfusion might be recommended if severe thrombocytopenia and bleeding occurs. Intravenous immunoglobulins, corticosteroids, rituximab, and plasma exchange should be reserved for patients with resistant thrombocytopenia and severe bleeding as mentioned in a number of reports.

Severe Thrombocytopenia in Adults with Severe Acute Respiratory Distress Syndrome: Impact of Extracorporeal Membrane Oxygenation Use

Extracorporeal membrane oxygenation (ECMO) use is perceived to cause thrombocytopenia (T), but the role of non-ECMO factors in the development of T remains unclear. We sought to evaluate the incidence and factors associated with severe T (platelet count ≤ 50,000/μl) in adults with severe acute respiratory distress syndrome (ARDS) managed with or without ECMO. The ECMO (n = 32) versus the non-ECMO (n = 53) groups had a similar baseline platelet count (214,000 vs. 179,000/μl), Acute Physiology and Chronic Health Evaluation (APACHE) II score (p = 0.13), unfractionated heparin (UFH) exposure (p = 0.62), and severe T incidence (25 vs. 19%, p = 0.5). Although the APACHE II score (p = 0.01), presence of liver failure (p = 0.08), and platelet transfusion (p = 0.0009) were different between the severe T (18/85 [21%]) and non-severe T groups (67/85 [79%]), the incidence of septic shock (p = 0.64), heparin infusion use (p = 0.41), exposure to non-heparin T-causing medications (p = 0.77) and ECMO use (p = 0.5) were not. An adjusted multivariate linear regression model revealed that only the APACHE II score was independently associated with the development of severe T (p = 0.01) but use of ECMO was not (p = 0.32) ECMO use may not affect the incidence of severe T among adults with severe ARDS. Larger studies that are prospective in nature are required to confirm this finding.

Thrombocytopenia in Critical Care Patients

Thrombocytopenia is a common laboratory finding in the intensive care unit (ICU) patient. Because the causes can range from laboratory artifact to life-threatening processes such as thrombotic thrombocytopenic purpura (TTP), identifying the cause of thrombocytopenia is important. In the evaluation of the thrombocytopenia patient, one should incorporate all clinical clues such as why the patient is in the hospital, medications the patient is on, and other abnormal laboratory findings. One should ensure that the patient does not suffer from heparin-induced thrombocytopenia (HIT) or one of the thrombotic microangiopathies (TMs). HIT can present in any patient on heparin and requires specific testing and antithrombotic therapy. TMs cover a spectrum of disease ranging from TTP to pregnancy complications and can have a variety of presentations. Management of disseminated intravascular coagulation depends on the patient’s condition and complication. Other causes of ICU thrombocytopenia include sepsis, medication side effects, post-transfusion purpura, catastrophic anti phospholipid antibody disease, and immune thrombocytopenia.

Thrombocytopenia and extracorporeal membrane oxygenation in adults with acute respiratory failure: a cohort study

PURPOSE

The association between extracorporeal membrane oxygenation (ECMO) use and the development of thrombocytopenia is widely presumed yet weakly demonstrated. We hypothesized that longer duration of ECMO support would be independently associated with worsened thrombocytopenia.

METHODS

We performed a single-center retrospective cohort study of 100 adults who received ECMO for acute respiratory failure. We used generalized estimating equations to test the association between days on ECMO and daily percentage of platelets compared to the first post-cannulation platelet count. We constructed a multivariable logistic regression model with backwards stepwise elimination to identify clinical predictors of severe thrombocytopenia (≤50,000/μL) while on ECMO.

RESULTS

Days on ECMO was not associated with a decrease in platelet count in the unadjusted analysis (β -0.85, 95 % CI -2.05 to 0.36), nor after considering and controlling for days hospitalized prior to ECMO, APACHE II score, platelet transfusions, and potential thrombocytopenia-inducing medications (β -0.83, 95 % CI -1.9 to 0.25). Twenty-two subjects (22 %) developed severe thrombocytopenia. The APACHE II score and platelet count at the time of cannulation predicted the development of severe thrombocytopenia. The odds of developing severe thrombocytopenia increased 35 % for every 5-point increase in APACHE II score (OR 1.35, 95 % CI 0.94-1.94) and increased 35 % for every 25,000/μL platelets below a mean at cannulation of 188,000/μL (OR 1.35, 95 % CI 1.10-1.64).

CONCLUSIONS

Duration of ECMO is not associated with the development of thrombocytopenia. The severity of critical illness and platelet count at the time of cannulation predict the development of severe thrombocytopenia while receiving ECMO for respiratory failure. Future studies should validate these findings, especially in cohorts with more venoarterial ECMO patients, and should characterize the association between thrombocytopenia and bleeding events while on ECMO.

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 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.

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.

Rifabutin-Induced Thrombocytopenia from Concurrent Use of High-Dose Fluconazole

Objective:

To report a case of—and review the literature supporting—rifabutin-induced thrombocytopenia from concurrent use of high-dose fluconazole.

Case Summary:

A 34-year-old man with AIDS, on a stable regimen that included rifabutin and fluconazole for the previous 3 months, was admitted to the hospital with symptoms of oropharyngeal candidiasis. He was treated with increased doses of fluconazole 200 mg to 800 mg daily over a 9-day hospital admission. During this time, his platelet count decreased from 441,000 cells/mm3 to 24,000 cells/mm3, with no signs of bleeding. He was discharged on day 9 and instructed to omit 1 dose of rifabutin and continue fluconazole 200 mg daily. On day 12, his platelet count was 118,000 cells/mm3. About 1 month after discharge, his platelet count was 151,000 cells/mm3.

Discussion:

Rifabutin is known to cause thrombocytopenia. Results from initial studies evaluating various doses of rifabutin were not conclusive as to whether rifabutin-induced thrombocytopenia is a dose-dependent effect. With increased use of rifabutin, often in combination with potentially interacting medications, reports of thrombocytopenia have gained frequency. One study showed that patients on higher doses of rifabutin experienced thrombocytopenia significantly more often than did those on lower doses. When rifabutin is administered with fluconazole, there is a clear pharmacokinetic interaction, showing a 76–82% increase in the rifabutin area under the concentration curve, with only uveitis and leukopenia reported. An objective causality assessment of this case classified the interaction between fluconazole and rifabutin, resulting in thrombocytopenia, as probable. Other causes of thrombocytopenia in our patient, including AIDS, Mycobacterium avium complex, fluconazole, famotidine, and ritonavir, are less likely.

Conclusions:

We describe the first case of rifabutin-induced thrombocytopenia from concurrent use of high-dose fluconazole. There is evidence to support this interaction and practitioners should be aware of this potential adverse effect.

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.

Implications of thrombocytopenia and platelet course on pediatric intensive care unit outcomes

INTRODUCTION

Thrombocytopenia has been shown to be an independent predictor of mortality and prolonged hospital length of stay in critically ill adults. Studies are lacking in the pediatric intensive care unit population. We evaluated the relationship between platelet counts at admission, platelet course, and outcomes.

HYPOTHESES

1) Thrombocytopenia at the time of admission to the pediatric intensive care unit is a risk factor for increased mortality and prolonged length of stay. 2) Thrombocytopenia at any point during pediatric intensive care unit stay is associated with increased mortality and length of stay. 3) Falling platelet counts during a pediatric intensive care unit course are associated with greater mortality and longer length of stay.

METHOD

Prospective observational study.

STUDY POPULATION

All patients admitted to a multidisciplinary tertiary care pediatric intensive care unit in a University Hospital over the course of a year. ANALYSIS OF DATA: Data were analyzed using logistic and linear regression.

RESULTS

Thrombocytopenia (platelet count <150 x 10/L) was present in 17.3% of pediatric intensive care unit patients on admission. Mortality was higher in thrombocytopenic patients (17.6% vs. 2.47%, p < 0.001). The median length of stay in the thrombocytopenia and nonthrombocytopenia groups was 4 days vs. 1.6 days, respectively (p < 0.001). The pediatric intensive care unit patients (25.3%) were thrombocytopenic at some point in their stay. They had higher mortality (17.1% vs. 0.9%, odds ratio [OR] 23.8, 95% confidence interval [CI] 5.2-108.6, p < 0.0005) and longer length of stay (median 6.6 days vs. 1.5 days, p < 0.0005) compared with those who were never thrombocytopenic. For every 10% fall in platelet count from the time of admission, the OR for mortality was 1.4 (95% CI 1.1-1.8) and the length of stay was longer (p < 0.0005). Patients with normal platelet counts at admission who later developed thrombocytopenia had increased mortality (OR 18.6, 95% CI 3.2-107.3) and longer length of stay (p < 0.0005) compared with those who did not develop thrombocytopenia.

CONCLUSION

Thrombocytopenia and falling platelet counts are associated with increased risk of mortality and length of stay in the pediatric intensive care unit.

Platelets in liver transplantation: friend or foe?

Apart from the well-known role of blood platelets in hemostasis, there is emerging evidence that platelets have various nonhemostatic properties that play a critical role in inflammation, angiogenesis, tissue repair and regeneration, and ischemia/reperfusion (I/R) injury. All these processes may be involved in the (patho)physiological alterations occurring in patients undergoing liver transplantation. Experimental and clinical research points toward a dualistic role of platelets in patients undergoing liver transplantation, resulting in both beneficial and detrimental effects. Although a low platelet count is generally considered a risk factor for perioperative bleeding, recent studies have indicated that platelet function in patients with cirrhosis may not be as abnormal as previously assumed. Platelet transfusions are frequently considered in liver transplant recipients to correct low platelet counts and to prevent bleeding; however, evidence-based transfusion thresholds are lacking, and the other detrimental and nonhemostatic properties of platelets are generally not weighed in this respect. First, platelets have been shown to contribute to I/R injury of the liver graft via induction of sinusoidal endothelial cell apoptosis. Second, platelet transfusion has been identified as an independent risk factor for reduced survival via mechanisms that are not completely understood yet. On the other hand, recent studies indicate that platelets are critically involved in restoration after liver injury and in liver regeneration via serotonin-mediated mechanisms. These findings make platelets both friend and foe in liver transplantation. The scientific challenge will be to further dissect the mechanisms and clinical relevance of these contrasting roles of platelets in liver transplantation.

Reducing thrombotic complications in the perioperative setting: an update on heparin-induced thrombocytopenia

Heparins are widely used in the perioperative setting. Immune heparin-induced thrombocytopenia (HIT) is a serious, antibody-mediated complication of heparin therapy that occurs in approximately 0.5%-5% of patients treated with heparin for at least 5 days. An extremely prothrombotic disorder, HIT confers significant risks of thrombosis and devastating consequences on affected patients: approximately 38%-76% develop thrombosis, approximately 10% with thrombosis require limb amputation, and approximately 20%-30% die within a month. HIT antibodies are transient and typically disappear within 3 mo. In patients with lingering antibodies, however, re-exposure to heparin can be catastrophic. In the perioperative setting, heightened awareness is important for the prompt recognition, diagnosis, and treatment of HIT. HIT should be considered if the platelet count decreases 50% and/or thrombosis occurs 5-14 days after starting heparin, with other diagnoses excluded. On strong clinical suspicion of HIT, heparin should be discontinued and a parenteral alternative anticoagulant initiated, even before laboratory confirmation of HIT is obtained. Subsequent laboratory test results may help with the decision to continue with nonheparin therapy or switch back to heparin. Heparin avoidance in patients with current or previous HIT is feasible in most clinical situations, except perhaps in cardiovascular surgery. If the surgery cannot be delayed until HIT antibodies have disappeared, intraoperative alternative anticoagulation is recommended.

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).

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.

Systemic coagulation changes caused by pulmonary artery catheters: laboratory findings and clinical correlation

BACKGROUND

A higher rate of pulmonary embolism has been associated with pulmonary artery (PA) catheters; however, no mechanism has been described. Conventional tests of coagulation reveal no changes related to PA catheterization. The purpose of this study was to determine whether PA catheterization resulted in a hypercoagulable state detectable by thrombelastography (TEG).

METHODS

ANIMAL

Healthy, anesthetized, swine (n = 19) underwent PA catheterization. Samples were drawn from 7F femoral arterial catheters before and two hours after PA catheterization, at 5 mL/min, and analyzed (native whole blood, n = 15, kaolin activated blood, n = 4) by TEG (Hemoscope, Niles, IL) at precisely two minutes. Human: An IRB-approved prospective, observational trial was conducted in critically ill patients (n = 19). Samples were drawn from 22-gauge radial artery catheters, before and three hours after PA catheterization. Kaolin-activated TEG samples were analyzed at precisely five minutes. Data are mean +/- SE; Groups were compared with analysis of variance and significance was assessed at the 95% confidence interval.

RESULTS

In both animals and patients, PA catheterization truncated R times (time to initial fibrin formation). In swine, the R times were 17.6 +/- 1.3 minutes (native) and 3.8 +/- 0.4 (kaolin) before PA catheterization, and decreased to 6.3 +/- 1.0 minutes (p = 0.002) and 1.9 +/- 0.5 minutes (p = 0.010) afterward. There were no changes in pH or temperature during the experiment. In patients, 4 of 19 were excluded for protocol violations. The R time was 6.3 +/- 1.0 minutes (kaolin) before and 3.0 +/- 0.3 minutes after catheterization (p = 0.003). No changes were observed in conventional coagulation parameters, temperature or pH.

CONCLUSION

In healthy swine, and critically ill patients, PA catheters may enhance thrombin formation and fibrin polymerization, indicating a systemic hypercoagulable state. This may explain why PA catheters are associated with an increased risk of pulmonary emboli.

Critical care clotting catastrophies

Coagulation problems are very common in intensive care patients. It is important to recognize potential problems, perform a rapid assessment, and start therapy. The author reviews general clinical and laboratory approaches to diagnosis and treatment of the bleeding patient and to correction of coagulopathies. This review outlines a set of often catastrophic coagulation problems, which may present both thrombotic and bleeding challenges. These include heparin induced thrombocytopenia, thrombotic thrombocytopenic purpura, and disseminated intravascular coagulation.

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.

Thrombocytopenia in Cardiovascular Patients

Thrombocytopenia is a common problem in cardiovascular patients, but the etiology and management of this condition may be different than those in other populations. Around the time that percutaneous coronary interventions are performed, the drugs most commonly associated with thrombocytopenia are the glycoprotein (GP) IIb/IIIa receptor inhibitors and heparin. Thienopyridines only rarely cause thrombocytopenia. Patients with non-ST-elevation acute coronary syndromes may be exposed to prolonged heparin infusions, GPIIb/IIIa inhibitors, and thienopyridines. After open-heart surgery, as opposed to other surgical procedures, the platelet count falls, primarily due to platelet damage and destruction in the bypass circuit and hemodilution. Heparin is the most common drug to be implicated in thrombocytopenia in ICU patients. Determining the etiology for the low platelet count is important for the implementation of appropriate management. The use of a direct thrombin inhibitor in treatment should be considered early if a diagnosis of heparin-induced thrombocytopenia is possible.

Cardiobacterium hominis endocarditis associated with very severe thrombocytopenia and platelet autoantibodies

Severe thrombocytopenia is a life-threatening condition. It is often associated with immune-mediated platelet destruction or myeloablative chemotherapy. Infective endocarditis has been associated with thrombocytopenia, which, as in sepsis, tends to be mild and is often the result of several pathological mechanisms. We report a case of Cardiobacterium hominis endocarditis associated with very severe thrombocytopenia and bleeding in a patient who refused platelet transfusion. Platelet autoantibodies directed against glycoprotein (Gp) IIb/IIIa and Gp Ib/IX were detected during active infection using a glycoprotein-specific assay. Successful treatment of C. hominis endocarditis was associated with loss of platelet autoantibodies and recovery of the platelet count. This report illustrates that the development of platelet autoantibodies can contribute to very severe thrombocytopenia in occasional patients with infective endocarditis.

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.

Coagulation/fibrinolysis abnormality and vascular endothelial damage in the pathogenesis of thrombocytopenic multiple organ failure

OBJECTIVE

Until recently, attention has been directed to disseminated intravascular coagulation as a cause of multiple organ failure (MOF). On the other hand, it has now become clear that humoral mediators play important roles in the pathogenesis of MOF. Therefore, we performed the present study in patients with thrombocytopenic MOF to investigate the relationship between various humoral mediators and vascular endothelial damage reported to be triggered by such humoral mediators in the pathogenesis of MOF.

DESIGN

A retrospective clinical study.

SETTING

Intensive care unit of a university hospital.

PATIENTS

The study included 18 thrombocytopenic patients whose conditions progressed to septic MOF (MOF group) and 20 others who did not progress to MOF (non-MOF group). The MOF group and non-MOF group were also presented with infection and with platelet counts of <100,000/mm3.

MEASUREMENTS AND MAIN RESULTS

The MOF group had fibrinolysis abnormality, as indicated by increased plasminogen activator inhibitor-1 level. On the other hand, the MOF group had increased polymorphonuclear elastase and polymorphonuclear-mediated fibrinogen degradation product levels with consequent prolonged elevation of thrombomodulin. In addition, both polymorphonuclear elastase and polymorphonuclear-fibrinogen degradation products were significantly positively correlated with thrombomodulin in the MOF group, but no such positive correlation was observed between interleukin-6 or plasminogen activator inhibitor-1 and thrombomodulin. In the non-MOF group, on the other hand, thrombomodulin exhibited no significant positive correlation with polymorphonuclear elastase, polymorphonuclear-fibrinogen degradation products, interleukin-6, or plasminogen activator inhibitor-1.

CONCLUSIONS

Our study provided evidence that vascular endothelial damage was the primary cause of organ failures in patients with thrombocytopenic MOF and that humoral mediators played a major role in the development of vascular endothelial damage in such patients. These results suggest that it is important to treat thrombocytopenic MOF as a condition of vascular endothelial damage, with weight placed on countermeasures against disorders of humoral mediators.

Thrombocytopenia in patients in the medical intensive care unit: bleeding prevalence, transfusion requirements, and outcome

OBJECTIVE

To determine prevalence, risk factors, and outcome of thrombocytopenia in medical intensive care patients.

DESIGN

Prospective observational study.

SETTING

The 12-bed medical intensive care unit of a university hospital.

PATIENTS

All consecutively admitted patients with normal platelet count at admission and an intensive care unit stay of >48 hrs during a 13-month period (n = 145).

MEASUREMENTS AND MAIN RESULTS

The prevalence of intensive care unit-acquired thrombocytopenia (platelet count, <150.0/nL) was 64 of 145 patients (44%). Intensive care unit mortality was 31% in thrombocytopenic patients and 16% in nonthrombocytopenic patients (p =.03). Mortality was higher in patients with a nadir platelet count of <100.0/nL (p <.001) and in patients with a drop in platelet count of >/=30% (p <.001). In nonsurvivors, the decrease in platelet count was greater (p <.001), the nadir platelet count lower (p <.001), and the duration of thrombocytopenia longer (p =.008) than in survivors. A logistic regression analysis identified septic shock (odds ratio [OR], 3.65; 95% confidence interval [CI], 1.40-9.52), a higher Acute Physiology and Chronic Health Evaluation II Score at admission (OR, 1.06 for 1 point; 95% CI, 1.01-1.12), and a drop in platelet count exceeding 30% (OR, 3.73; 95% CI, 1.24-11.21), but not thrombocytopenia, as independent risk factors for intensive care unit death. Correction of thrombocytopenia was associated with reduced mortality (OR, 0.002; 95% CI, 0-0.08). Major bleeding prevalence and transfusion requirements were significantly higher with thrombocytopenia. Nadir platelet count was the only independent risk factor for bleeding (OR, 4.1 for every 100.0/nL; 95% CI, 1.9-8.8). Independently associated with thrombocytopenia were disseminated intravascular coagulation (OR, 14.94; 95% CI, 3.92-57.00), cardiopulmonary resuscitation as an admission category (OR, 5.17; 95% CI, 1.42-18.85), and a higher Sequential Organ Failure Assessment score (OR, 1.20 for a 1 point change; 95% CI, 1.02-1.40).

CONCLUSIONS

Thrombocytopenia is common in medical intensive care unit patients. Thrombocytopenic patients have a higher prevalence of bleeding and greater transfusion requirements. A drop in platelet counts of > or = 30%, but not thrombocytopenia per se, is independently associated with intensive care unit death. Serial measurements of platelet counts are important and readily available markers for monitoring the patient's condition. Any drop in platelet count requires urgent clarification. Disseminated intravascular coagulation, signs of organ failure at admission, and cardiopulmonary resuscitation are predictors of intensive care unit-acquired thrombocytopenia.

Bioactive oxidized lipids in the plasma of cardiac surgical intensive care patients

Critical illness is associated with increased oxidative stress that may give rise to the formation of lipid hydroperoxides (LOOH) and various secondary degradation products such as fragmented phosphatidylcholine (FPC) and lipids related to the platelet-activating factor (PAF). Because some oxidized phospholipids are potent proinflammatory agents, we measured the concentration of LOOH, FPC, and PAF-like activity in blood plasma of 36 patients who had undergone cardiac surgery and developed postoperative complications associated with systemic inflammatory response syndrome (SIRS) or multiple organ failure (MOF). These patients were compared to two control groups, namely preoperative patients scheduled for cardiac surgery (n = 13), and postoperative patients without complications (n = 19). Postoperative patents had higher concentrations of LOOH and lower concentrations of FPC than preoperative patients (P < 0.01). However, SIRS and MOF had no significant effect on the concentration of oxidatively modified lipids. This is despite the fact that MOF patients showed evidence of increased lipid peroxidation (7-fold higher ratio of alpha-tocoquinone/alpha-tocopherol compared to control). LOOH correlated positively with the white blood cell count. Postoperative patients had 4-fold higher plasma activities of phospholipase A2 and this activity was further increased in patients with SIRS (P < 0.04). Phospholipase A2 activity correlated negatively with the concentration of FPC. The data suggest that oxidatively modified lipids do not accumulate in patients with SIRS and MOF, perhaps because enhanced peroxidation of lipids is offset by enhanced lipolytic activity.

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

STUDY OBJECTIVE

To identify independent risk markers for thrombocytopenia in critically ill patients.

DESIGN

Prospective, observational study.

SETTING

Eleven-bed intensive care unit-coronary care unit (ICU-CCU) in a community hospital.

PATIENTS

Three hundred sixty-two consecutive patients meeting inclusion criteria during 1 year.

INTERVENTION

Potential risk marker data were collected on admission to the ICU-CCU and for the period before development of thrombocytopenia (defined as two or more consecutive platelet counts < 150 x 10(3)/mm3 obtained at least 12 hours apart), or for the duration of ICU-CCU stay if thrombocytopenia did not develop.

MEASUREMENTS AND MAIN RESULTS

Thrombocytopenia developed in 68 patients (18.8%). Multivariate logistic regression analyses identified patients at risk on admission, but the predictive, potential of the regression model improved when all risk marker exposures during the ICU-CCU stay were considered. Independent risk markers included fresh frozen plasma administration, sepsis, musculoskeletal diagnosis, pulmonary artery catheter insertion, gastrointestinal diagnosis, packed red blood cell administration, and nonsurgical respiratory diagnosis. Higher admission platelet count and aspirin administration were associated with a lower risk of thrombocytopenia. Heparin administration was not identified as a risk marker, and no patient developed heparin-induced thrombocytopenia with thrombosis. Patients with thrombocytopenia had longer ICU-CCU and hospital stays, and higher ICU-CCU and hospital mortality than those without thrombocytopenia.

CONCLUSIONS

Development of thrombocytopenia in critically ill patients is associated with specific diagnoses, packed red cell and fresh frozen plasma transfusions, pulmonary artery catheter insertion, and admission platelet count.

Treatment of drug-induced thrombocytopenia

Estimates on the incidence of drug-induced thrombocytopenia range 5-40% in patients receiving heparin to < 1% with other causative agents. Systematically assessing drug-induced thrombocytopenia through a series of steps, each step providing additional evidence that the suspected agent is the true cause of thrombocytopenia, is the best way to identify the causative agent. Databases exist to aid in identification of the causative agent. Knowing which medications may be causative agents as well as which are not known to cause drug-induced thrombocytopenia, the aetiologies of drug-induced thrombocytopenia, signs and symptoms of thrombocytopenia and strategies to treat thrombocytopenia associated with specific agents will provide the clinician with the necessary skills to make proper medical decisions.

Epidemiologic and outcome studies of patients who received platelet transfusions in the neonatal intensive care unit

STUDY DESIGN

We conducted a historic cohort study of neonates who received platelet transfusions at the National Institute of Perinatology, Mexico City, from January 1997 to May 2000. We obtained descriptive and outcome data, and assessed demographic and laboratory means of predicting "good candidates" for a future recombinant thrombopoietin (rTpo) trial.

RESULTS

A minority of the transfused patients (11.4%) received only one transfusion; the majority (88.6%) received multiple transfusions. Neonates who received one or more platelet transfusions were more likely to die (24.5% mortality) than neonates who received no platelet transfusions (3.7% mortality). Regression analyses indicated that the presence of liver disease was the best predictor of a "good candidate" for rTpo administration.

CONCLUSION

The majority of neonates in our institution who receive platelet transfusions receive multiple, not single, transfusions. Receiving any platelet transfusion is a marker for high risk of death. Neonates with liver disease who receive platelet transfusions might be a reasonable group for a phase I rTpo trial.

Platelet transfusions in the neonatal intensive care unit:factors predicting which patients will require multiple transfusions

BACKGROUND

Previous studies suggest that recombinant thrombopoietin (rTPO) will increase platelet production in thrombocytopenic neonates. However, the target populations of neonates most likely to benefit should be defined. Studies suggest that rTPO will not elevate the platelet count until 5 days after the start of treatment. Therefore, the neonates who might benefit from rTPO are those who will require multiple platelet transfusions for more than 5 days. This study was designed to find means of prospectively identifying these patients.

STUDY DESIGN AND METHODS

A historic cohort study of all patients in the neonatal intensive care unit (NICU) at the University of Florida who received platelet transfusions from January 1, 1997, through December 31, 1998, was conducted.

RESULTS

Of the 1389 patients admitted to the NICU during the study period, 131 (9.4%) received platelet transfusions. Seventeen were treated with extracorporeal membrane oxygenation and were excluded from further analysis. Of the remaining 114 patients, 55 (48%) received one transfusion and 59 (52%) received more than one transfusion (21 had >4). None of the demographic factors examined predicted multiple platelet transfusions. However, two clinical conditions did; liver disease and renal insufficiency. Neonates who received one platelet transfusion had a relative risk of death 10.4 times that in neonates who received none (p = 0.0001). Neonates who received >4 platelet transfusions had a risk of death 29.9 times that in those who received no transfusions (p = 0.0001).

CONCLUSION

NICU patients with liver disease or renal insufficiency who receive one platelet transfusion are likely to receive additional transfusions. Therefore, these patients constitute a possible study population for a Phase I/II rTPO trial.

Blunted rise in platelet count in critically ill patients is associated with worse outcome

OBJECTIVE

To test the hypothesis that a low rate of change of platelet counts (PCs) after admission to the intensive care unit (ICU) is associated with mortality. Low PCs are known to be associated with disease severity in critically ill patients, but the relevance of time-dependent changes of PCs has not been investigated.

DESIGN

Retrospective study.

SETTING

A 12-bed surgical ICU of a university hospital.

PATIENTS

All adult patients admitted to the ICU for at least 4 days during a 7-yr period.

INTERVENTIONS

At admission, Acute Physiology and Chronic Health Evaluation scores were calculated. PCs and leukocyte counts were analyzed from admission to day 10. The daily rise of the PCs (deltaPC/deltat from day 2 to day 10 was calculated. Rates for 30-day mortality as well as hospital mortality were determined.

MEASUREMENTS AND MAIN RESULTS

A total of 1,415 admissions were studied. Median PCs (interquartile range) initially decreased and subsequently increased, with a higher PC in 1,203 survivors than in 212 nonsurvivors from day 2 onward (302 [range,181-438] x 10(3)/mm3/day vs. 129 [range, 62-228] x 10(3)/mm3 at day 10; p < 0.001). After stratification of patients per type of surgery, within each group PC was also higher in survivors. Mean deltaPC/deltat was more than five times higher in survivors compared with nonsurvivors: 30 +/- 46 x 10(3)/mm3/day vs. 6 +/- 28 x 10(3)/mm3/day (p < 0.001). The area under the receiving operating characteristic curve of deltaPC/deltat for 30-day survival was 0.743 compared with 0.728 for the Acute Physiology and Chronic Health Evaluation. Leukocyte counts showed marginal differences between nonsurvivors and survivors.

CONCLUSION

A blunted or absent rise in PCs in critically ill patients is associated with increased mortality. deltaPC/deltat is a readily available and simple parameter to improve assessment of critically ill patients.