Hypoalbuminemia in Critically Ill Children
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ARTICLE Hypoalbuminemia in Critically Ill Children Ira N. Horowitz, MD; Kenneth Tai, MD Objective: To evaluate whether hypoalbuminemia on Main Outcome Measures: Length of PICU and hos- admission is a predictor of adverse outcome in critically pital stays, receipt and length of ventilatory support, sur- ill children. vival, pediatric risk of mortality score, mortality risk, and number of organ failures. Design: Retrospective medical record review. Results: Controlling for mortality risk, the hypoalbu- Setting: A 14-bed medical and surgical pediatric inten- minemia group had a longer average stay in the PICU sive care unit (PICU). (8.08 vs 4.41 days; 95% confidence interval [CI] for dif- ference,1.02-6.32) and the hospital (11.36 vs 6.63 days; Participants: All patients admitted to the PICU from 95% CI for difference,1.31-8.16) than did the normal al- January 1, 1998, through December 31, 2000, under the bumin level group. The hypoalbuminemia group had a care of the PICU team or trauma service and whose al- lower survival rate (odds ratio,0.10; 95% CI, 0.02-0.46) bumin level was measured were potential subjects. One and a higher number of organ failures (1.38 vs 0.65; 95% hundred fifty-five patients were divided into 4 groups on CI for difference, 0.40-1.04). the basis of age and appropriate albumin level for that age group. The groups of hypoalbuminemic patients were combined (hypoalbuminemia group) and compared with Conclusion: Admission hypoalbuminemia is a signifi- the combined group of patients with albumin levels above cant marker of morbidity and mortality in critically ill the reference cutoff (normal albumin level group). children. Exposure: Serum albumin level. Arch Pediatr Adolesc Med. 2007;161(11):1048-1052 LBUMIN IS THE MOST ABUN- exchange between intravascular and extra- dant protein in blood vascular compartments. plasma, usually constitut- Hypoalbuminemia is associated with ing up to two-thirds of total poor outcomes in adult critical illness, but plasma protein.1 It contrib- whether this association exists in pediat- Autes about 80% of the plasma colloid os- ric patients remains unclear.2-6 There is a motic pressure and is responsible for the paucity of data evaluating serum albu- transport and binding of many molecules. min level on admission as a predictor of Albumin is highly water soluble and re- outcome in critically ill children. Our goal sides in the extracellular space, with one- was to evaluate whether hypoalbumin- third in the intravascular space and two- emia on admission is a marker of adverse thirds in the extravascular space. Typically, outcome in this population. hypoalbuminemia is ascribed to dimin- ished synthesis (eg, malnutrition, malab- METHODS sorption, or hepatic dysfunction) or in- creased losses (eg, urinary losses with nephropathy or protein-losing enteropa- We performed a retrospective medical record thy). Diversion of synthetic capacity to other review of data collected from January 1, 1998, Author Affiliations: proteins (acute-phase reactants) is an- through December 31, 2000, in the pediatric Department of Pediatrics, other cause of hypoalbuminemia. Inflam- intensive care unit (PICU) at the Ronald Loyola University Medical McDonald Children’s Hospital of Loyola Uni- Center, Maywood, Illinois. matory disorders can accelerate the catabo- versity Medical Center. Any pediatric patient Dr Horowitz is now with lism of albumin while simultaneously whose albumin level was measured was a po- Pediatric Critical Care, decreasing its manufacture. During criti- tential subject. Patients were stratified by age Morristown Memorial Hospital, cal illness, capillary permeability in- and serum albumin level on admission. Hypo- Morristown, New Jersey. creases dramatically and alters albumin albuminemia was defined as an albumin level (REPRINTED) ARCH PEDIATR ADOLESC MED/ VOL 161 (NO. 11), NOV 2007 WWW.ARCHPEDIATRICS.COM 1048 ©2007 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/24/2021 Table 1. Criteria for Failure of Specific Organ Systemsa Organ System Criteria Cardiovascular MAP, Ͻ 40 mm Hg (infants aged Ͻ 12 mo) MAP, Ͻ 50 mm Hg (children aged Ն 12 mo) HR, Ͻ 50 beats/min (infants aged Ͻ 12 mo) Respiratory HR, Ͻ 40 beats/min (children aged Ն 12 mo) Cardiac arrest Continuous vasoactive drug infusion for hemodynamic support RR, Ͼ 90/min (infants aged Ͼ 12 mo) RR, Ͼ 70/min (children aged Ն 12 mo) PaO2, Ͻ 40 mm Hg (in absence of cyanotic heart disease) PaCO2, Ͻ 65 mm Hg PaO2:FIO2, Ͻ 250 mm Hg Ventilatory support (Ͼ 24 h if postoperative) Tracheal intubation for airway obstruction or acute respiratory failure Neurologic Glasgow coma scale score, Ͻ 5 Fixed, dilated pupils Persistent (Ͼ 20 min) intracranial pressure Ͼ 20 mm Hg or need for therapeutic intervention Hematologic Hemoglobin level, Ͻ 5 g/dL WBC count, Ͻ 3 ϫ103 cells/µL Platelet count, Ͻ 20 000/µL Disseminated intravascular coagulopathy (PT Ͼ 20 s or aPTT Ͼ 60 s in presence of positive FSP assay results) Renal SUN level, Ͼ 100 mg/dL Serum creatinine level, Ͼ 2 mg/dL Need for dialysis Gastrointestinal Blood transfusions, Ͼ 20 mL/kg in 24 h because of gastrointestinal hemorrhage (endoscopic confirmation optional) Hepatic Total bilirubin level, Ͼ 5 mg/dL and SGOT or LDH more than twice the reference value (without evidence of hemolysis) Hepatic encephalopathy Ն grade II10 Abbreviations: aPTT, activated partial thromboplastin time; FIO2, fraction of inspired oxygen; FSP, fibrin split products; HR, heart rate; LDH, lactic dehydrogenase; MAP, mean arterial pressure; PT, prothrombin time; RR, respiratory rate; SGOT, serum glutamic oxaloacetic transminase; SUN, serum urea nitrogen; WBC, white blood cell. SI conversion factors: To convert bilirubin to micromoles per liter, multiply by 17.104; creatinine to micromoles per liter, by 88.4; platelet count to number of cells ϫ109 per liter, multiply by 10; urea nitrogen to millimoles per liter, by 0.357; and WBC count to number of cells ϫ109 per liter, multiply by 0.001. a Reproduced with permission from Wilkinson et al.9 of less than 3.4 g/dL for patients 7 months or older and less experienced significant blood loss during surgery (Ͼ10% of than 2.5 g/dL for patients younger than 7 months.7 (To con- their blood volume), or received blood products or albumin vert albumin to grams per liter, multiply by 10.) All patient data before measurement of the albumin level were also excluded. were combined according to age-specific definitions of hypo- Data recorded included age, sex, diagnosis (categorized by albuminemia. Our institutional review board approved the organ system, eg, respiratory, infectious, neurologic, or car- project and waived the need for consent. diac), pediatric risk of mortality (PRISM) score,8 risk of mor- tality computed from the PRISM score, length of hospital stay, INCLUSION CRITERIA length of PICU stay, receipt and length of ventilatory support, number of organ failures9 (Table 1), outcome (survival), com- All patients admitted to the PICU under the care of the PICU plications, and whether the patient received supplemental al- team or trauma service whose albumin level was measured were bumin. Except for death in an extremely ill child, complica- potential subjects. Arrival to the PICU was required no later than tions were all unexpected, untoward events such as nosocomial the second hospital day, if the patient was initially admitted to pneumonia, decubitus ulcer, or reintubation. the floor. A comprehensive metabolic profile or albumin level was obtained within 48 hours of admission to the hospital. DATA ANALYSIS EXCLUSION CRITERIA Mortality probability was used as a control variable when groups, which were divided according to their albumin level (hypoal- Patients who were not expected to have a normal albumin level buminemic patients [hypoalbuminemia group] vs patients with (ie, a level above the reference cutoff value for their age) in their a normal albumin level [normal albumin level group]) were usual state of health were excluded. Therefore, patients who compared on all outcome variables. Because both the PRISM were malnourished (below the fifth percentile according to and risk of mortality scores were highly skewed, we computed growth curve data) or who had lost weight (Ͼ10% of their body the logarithm of risk of mortality. Analyses of covariance were weight in the premorbid state) were excluded. Other exclu- used to compare the groups on scaled variables (eg, number sion criteria included presence of a chronic disease affecting of organ failures) using the logarithm of mortality risk as a co- the growth and development of the gastrointestinal system (fail- variate. The Mantel-Haenszel test was used to compare the ure to thrive or inflammatory bowel disease) or the kidney (end- groups on categorical variables (eg, survival). In these categori- stage renal disease or proteinuria), receipt of home parenteral cal analyses, mortality risk was controlled with a dichotomy nutrition, or presence of a chromosomal, genetic, or inborn meta- of the logarithm of mortality risk. A median split was used to bolic disorder. Patients who had undergone cardiac surgery, define low and high risk. (REPRINTED) ARCH PEDIATR ADOLESC MED/ VOL 161 (NO. 11), NOV 2007 WWW.ARCHPEDIATRICS.COM 1049 ©2007 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/24/2021 Table 2. Diagnostic Groups Patients Aged Ͻ 7mo Patients Aged Ն 7mo Hypoalbuminiaa Normal Albumin Level Hypoalbuminiab Normal Albumin Level Diagnosis by Organ System (n=10) (n=27) (n=41) (n=77) Neurologic 0 6 9 27 Respiratory 1 10 8 13 Infectious disease 5 2 9 3 Cardiovascular 1 3 7 5 Metabolic 1 1 1 10 Toxicology 0 0 1 12 Hematology 0 2 6 3 Gastrointestinal 2 3 0 0 Trauma 0 0 0 2 Renal 0 0 0 1 Rheumatologic 0 0 0 1 a In patients younger than 7 months, hypoalbuminia was defined as an albumin level of less than 2.5 g/dL (to convert to grams per liter, multiply by 10).