Natural history of nonimmune-mediated thrombocytopenia and acute kidney injury in pediatric open-heart surgery.

OBJECTIVE: Thrombocytopenia and acute kidney injury (AKI) are common following pediatric cardiac surgery with cardiopulmonary bypass (CPB). However, the relationship between postoperative nadir platelet counts and AKI has not been investigated in the pediatric population. Our objective was to investigate this relationship and examine independent predictors of AKI. DESIGN: After IRB approval, we performed a retrospective review of the institution's medical records and database. SETTING: This study was performed at a single institution over a 5-year period. PATIENTS: We included patients <21 years of age undergoing cardiac surgery with CPB. INTERVENTIONS: Demographics, laboratory, and surgical characteristics were captured, and clinical event rates were recorded. MEASUREMENTS: Descriptive statistics were used to evaluate platelet and creatinine distributions. T-tests and chi-squared tests were used to compare characteristics among Acute Kidney Injury Network groups. Multivariable logistic and ordinal logistic regression models were used to determine the association of our predictor of interest, postoperative nadir platelet count and AKI. RESULTS: Eight hundred and fourteen patients (23% infants and 23% neonates) were included in the analysis. Postoperative platelet counts decreased 48% from baseline reaching a mean nadir value of 150 × 109 ·l-1 on postoperative day 3. AKI occurred in 37% of patients including 13%, 17%, and 6% with Acute Kidney Injury Network stages 1, 2, and 3, respectively. The magnitude of nadir platelet counts correlated with the severity of AKI. Independent predictors of severity of AKI include nadir platelet counts, CPB time, Aristotle score, patient weight, intra-operative packed red blood cell transfusion, and having a heart transplant procedure. CONCLUSIONS: In pediatric open-heart surgery, thrombocytopenia and AKI occur commonly following CPB. Our findings show a strong association between nadir platelet counts and the severity of AKI.

A change in anticoagulation monitoring improves safety, reduces transfusion, and reduces costs in infants on cardiopulmonary bypass.

BACKGROUND: An immature coagulation system coupled with the hypothermia and hemodilution associated with cardiopulmonary bypass (CPB) in infants makes the activated clotting time (ACT) an ineffective monitor for anticoagulation in this population. The Medtronic HMS Plus Hemostasis Management System (HMS; Medtronic, Inc., Minneapolis, MN, USA) is shown to decrease thrombin generation and blood product requirements. AIM: We conducted a quality improvement initiative to test our hypothesis that the use of HMS results in reduced incidence of subtherapeutic ACT values, blood product usage, and operating room time for infants undergoing cardiac surgery. METHODS: Fifty consecutive patients weighing <10 kg having cardiac surgery requiring CPB had anticoagulation managed by the HMS. Data were compared to that of 50 consecutive patients weighing <10 kg having cardiac surgery who had their anticoagulation monitored by the ACT alone. Comparisons between categorical variables were performed with chi-square tests. Comparisons between continuous variables were performed with the Wilcoxon rank-sum test. Statistical significance was defined as two-tailed P value < 0.05. RESULTS: The HMS group had a 61% decrease in incidence of ACT values <480 s and elimination of ACT values < 400 s at any time on bypass. The HMS group received fewer blood products and spent fewer minutes in the operating room after protamine administration, translating to fewer donor exposures and a savings of $403 in transfusion costs and $440 in operating room time costs. CONCLUSION: Our findings highlight the benefits of individualized heparinization for pediatric patients undergoing CPB with a monitored heparinization system.

Morte Encefálica / Brain Death

Justificativa e Objetivos: O anestesiologista tem participado de procedimentos cirúrgicos relativos aos transplantes de órgäos e tecidos que envolvem doadores com o diagnóstico de morte encefálica. Pode defrontar-se também com o problema nas unidades de recuparaçäo pós-anestésicas e unidades de terapia intensiva. O objetivo desta revisäo é verificar os novos critérios para o diagnóstico de morte encefálica. Conteúdo: O diagnóstico da morte encefálica envolve um exame clínico adequado e exames complementares. Na investigaçäo clínica deve ser feito o diagnóstico etiológico do coma. No exame clínico devem ser avaliados os reflexos do tronco cerebral, pupilar, corneano, nauseoso, óculo-vestibulares e os movimentos dos olhos. Os exames complementares utilizados para o diagnóstico da morte encefálica säo divididos segundo o tipo de parâmetro fisiológico estudado pela angiografia cerebral, cintilografia radioisotópica, tomografia por emissäo de fóton único, tomografia cerebral com xenônio, tomografia por emissäo de positrons e doppler transcraniano. A atividade metabólica cerebral é estudada pela tomografia por emissäo de positrons. A atividade elétrica é avaliada pelo EEG e pelos potenciais evocados somatossensitivos. Conclusöes: Com exame clínico acurado e alguns exames complementares pode-se hoje, com mais segurança, atestar a morte em pacientes com perda irreversível das funçöes cardiorrespiratórias e cerebrais