The study was a pilot, prospective, randomized, open-label clinical trial, conducted between December 2010 and August 2011 at the Acute Care Unit (ACU), the paediatric emergency unit of Mulago Hospital, the national referral hospital in Kampala, Uganda. Children aged six months to 59 months were enrolled if they fulfilled all the following criteria: i) a positive blood smear for malaria, ii) severe anaemia (Hb ≤5 g/dL), iii) lactic acidosis (blood lactate ≥5 mmol/L), and iv) written informed consent from the parent or guardian. Children with known or concurrent cardiac disease and those undergoing transfusion with blood products other than packed red cells were excluded.
Verbal screening consent to obtain a blood lactate was initially sought from the caretaker in the emergency room to identify those with lactate ≥5 mmol/L who fulfilled the inclusion criteria. Full written consent from the caretaker was done later after resuscitating the child. Blood smear for malaria and haemoglobin estimation are routine tests at the paediatric emergency unit of Mulago Hospital. Eligible children were randomized using the sealed envelopes method into two treatment arms: short storage arm (one to 10 days) and long storage arm (21–35 days).
All children were transfused with packed red blood cells (RBCs) supplied directly from the Uganda Blood Transfusion Service centre based at Nakasero, Kampala. The transfusion centre collects volunteer donor blood and routinely tests all donated blood for HBsAg and for antibodies to HIV, HCV and syphilis within twenty four hours prior to release to the hospital. Blood was stored as packed RBCs in SAGM anticoagulant-preservative solution with an expiration date of 35 days from the date of collection. The blood was kept at the ACU blood bank, refrigerated at temperature ranges of 4-8°C. When multiple blood units were available for a particular treatment arm, the actual unit to be transfused was selected at random. Blood transfusions were according to local standard practice which is (approximate) 10 ml of packed RBCs per kg body weight of the child; transfused over 50–60 min by gravity infusion. Children were transfused with compatible blood after grouping (ABO and Rhesus groups) and cross-matching. The volume of blood transfused was computed using its weight (bag weight at pretransfusion minus its post transfusion weight, divided by the specific gravity of blood (1.06)).
The study variables included: sociodemographic characteristics, laboratory (blood smear for malaria parasites and quantitative parasite count), and clinical data: blood pressure (Omron 7051T), heart rate, oxygen saturation (Nonin Medical Inc, USA, Model 2500), respiratory rate, capillary blood lactate (Lactate Pro, Arkray, Japan), and haemoglobin (Hemocue, Angelholm, Sweden). Values were recorded on a standardized case report form at baseline and follow up at 2, 4, 6, 8, 12, and 24 hours post-transfusion until lactate levels fell to <5 mmol/L. The outcome measure was the proportion of transfused children who resolved lactic acidosis by four hours from the start of the transfusion. Apart from blood transfusion, all enrolled children received routine standard treatment for severe malaria with intravenous quinine. Apart from intravenous quinine given in 5% dextrose, children received no additional fluid therapy.
Data was double entered using EPI –DATA (version 3.2), exported to SPSS (version 12) for analysis. Analysis was done by intention to treat. The proportion of children from each group who achieved the primary outcome was compared using the Chi-squire test for categorical variables. The student’s t-test was used for comparing means of continuous variables of normal distribution. The Kaplan Meier survival curve was used to analyse differences in time to LA resolution between the two groups. Significance was assigned to p-values <0.05.
Quality control measures included: the case report form for data collection was pre-tested by the principal investigator on five subjects; the research assistants were trained on data collection procedures; the blood lactate meter was calibrated at least twice a month using the disposable calibration strip that came from inside of each packet of twenty five strips; and, measurements of blood pressure, respiratory rate and weight of child were taken twice, and the average of the two readings recorded.
Parents or guardians of participating children provided written informed consent and were free to voluntarily withdraw at any time. Confidentiality and participant anonymity were explained to those providing consent. Permission to carry out the study was obtained from the Department of Paediatrics and Child Health of the College of Health Sciences. The study was approved and cleared by the institutional Review Committee (IRC) of the College of Health Sciences, Makerere University. The trial was registered (NCT01580111).
A Data and Safety Monitoring Board (DSMB) composed of three senior faculty members (a paediatrician, a statistician and a haematologist) oversaw ethical conduct of this trial. Any serious adverse event was recorded and reported to the DSMB within 24 hours of occurrence. The DSMB reviewed study progress after 25% and 50% recruitment and at the end of the study. No difference in the rate of adverse events in the two treatment arms was observed.