Arwa Z. Al-Riyami

Validation of a non-invasive pulse CO-oximetry based hemoglobin estimation in normal blood donors

INTRODUCTION Non-invasive hemoglobin estimation may increase the recruitment of blood donors. CO-oximetry hemoglobin estimation is a non-invasive method used to estimate the hemoglobin level. The primary objective of this study is to validate the pulse CO-oximetry based hemoglobin estimation in normal blood donors. METHODS We conducted a prospective observational study on 106 in a tertiary care hospital blood bank over a period of 4 weeks. We performed a Spot Hemoglobin concentration (Sp Hb) using Masimo Pronto-7 Pulse CO-oximetry, and compared it to a venous sample Hb concentration (Reference Hemoglobin; Ref Hb) measured using Abbott CELL-DYN Sapphire hematology analyzer. Age, gender, weight, height, blood pressure and reference hemoglobin were used in the multivariable linear regression model of the difference in measurement. RESULTS Total of 106 donors (98 males, 8 females) were enrolled with a mean age and Ref Hb of 27 years (SD 6.2; 18-49) and 14.2 g/dL (SD 1.2; 11.5-17) respectively. The mean Sp Hb was 14.4 g/dL (SD 1.2;11.3-16.7). The mean difference between the Sp Hb and Ref Hb was 0.2 g/dL (SD 1.2;-4.5 to 3) with a correlation coefficient of 0.46 (R(2)=21%). In the multivariable model, height (p=0.015) and Hb level (p<0.001) were statistically significant predictors. A strong correlation was found between the two CO-oximetry Hb measurements (coefficient 0.78, R(2)=60%). CONCLUSIONS Our study validated the use of the CO-oximetry in blood donors. Larger prospective studies are needed to confirm our results.

Transfusion indication predictive score: a proposed risk stratification score for perioperative red blood cell transfusion in cardiac surgery

Red blood cell transfusion is known to be associated with increased morbidity and mortality in cardiac surgery. This study was performed to derive a score to predict that risk in our patients.

The pneumatic tube system does not affect complete blood count results; a validation study at a tertiary care hospital

Effect of the pneumatic tube system (PTS) on sample quality is controversial. Herein we aim at evaluating the impact of sample transportation via the PTS on complete blood count (CBC) results.

Discriminatory power of the intraoperative cell salvage use in the prediction of platelet and plasma transfusion in patients undergoing cardiac surgery

INTRODUCTION We aim to assess the discrimination of transfused salvaged blood in predicting perioperative platelet and plasma transfusion. METHODS Retrospective review was performed on all patients undergoing cardiac surgery with cell saver (CS) support. The area under the receiver operating characteristics curve was calculated. RESULTS The discrimination achieved by transfused CS volumes in predicting perioperative platelet and plasma transfusion was poor (AUC 0.642 and 0.613 respectively). None of the covariates included (preoperative platelets, cardiopulmonary bypass use and time, aortic cross clamp time and use of aspirin or clopidogrel within 7 days of surgery) were statistically significant predictors. CONCLUSION Volumes of transfused CS blood have poor discrimination in predicting platelet and plasma transfusion.

Safety of stem cell mobilization in donors with sickle cell trait

High WBC plays a major role in the pathogenesis of many of the complications seen in patients with sickle cell disease (SCD).1 Individuals with Sickle cell trait may develop SCD-related complications in conditions of severe stress.2 G-CSF increases the WBC and may contribute to some of the complications in individuals with sickle cell trait when used in stem cell mobilization. To the best of our knowledge, only one small study3 assessed the safety of the mobilization of stem cells in individuals with sickle cell trait. Herein, we aimed to compare mobilization adverse events between donors with and without sickle cell trait.

Validation of a noninvasive pulse CO-oximetry-based hemoglobin estimation in patients with sickle cell disease

Sir, Sickle cell disease (SCD) is an inherited hemoglobinopathy that results from replacement of glutamic acid by valine at the 6th position in the beta globin chain [1]. Patients with SCD are frequently admitted with various types of crises [1]. They require frequent venous punctures for investigations to manage and monitor the disease and its complications. Difficult venous access is not uncommon in this population, which frequently necessitates obtaining a central venous access [2] . Noninvasive Hemoglobin (Hb) estimation would simplify the care of these patients especially when they need daily Hb measurements. Masimo Pronto-7 is a portable device that can provide a noninvasive pulse CO-oximetry Spot Hb estimation (Sp Hb) as well as continuous Hb monitoring [3–6]. This machine has been investigated in the setting of intensive care unit (ICU) as a continuous Hb monitor [4]. It has an advantage in patient with SCD through its noninvasive method of Hb estimation. To the best of our knowledge, there is no study that validated this method in patients with SCD. The primary objective of this study is to validate this method of Hb estimations in patients with SCD. Secondary objectives include finding the impact of different baseline variables on the accuracy of the estimation and to assess the reproducibility of the Hb estimation by this method. This is a prospective observational study conducted in Sultan Qaboos University Hospital (SQUH, tertiary care center) between mid March to mid April 2012. All adult patients with SCD admitted to the inpatient ward during 4 weeks of recruitment were approached for the study. We used Rainbow adult reusable sensors (connected to a Masimo Pronto-7 Pulse CO-oximetry device). Two spot Hb measurements (Sp1 Hb & Sp2 Hb) were taken 10 min apart. Reference Hemoglobin (Ref Hb) levels were estimated using the CELL-DYN SAPPHIRE (Abbott Diagnostics, USA) [7]. The study was approved by ethics board of the SQUH. Continuous variables were expressed as mean with standard deviation (SD) and range (lowest–highest) if normally distributed. Categorical variables were expressed as frequency and percentage with the 95% confidence interval (CI) for the outcome variables. Scatter plots with fitted line and 95% CI of the line were used to compare between two continuous variables (Ref Hb vs. Sp1 Hb and Sp1 Hb vs. Sp2 Hb). Linear regression model was used to estimate the intercept, the beta coefficients of the regression equation (Ref Hb over Sp1 Hb and Sp1 Hb over Sp2 Hb), and the coefficient of determination (R). R was used as an estimate of the goodness of fit of the test. Multivariable linear regression was used to estimate the impact of different baseline characteristics and the discrepancy between the test and Ref Hb measurements. Variables entered in the model were age, gender, weight (Kg), height (cm), Ref Hb (g/dL), and blood pressure (BP; mmHg). Pearson correlation was used to estimate the correlation coefficient. All statistical tests were two-sided, and P value of 0.05 was used for statistical significance. All descriptive and analytical tests and graphs were performed using STATA 11 (StataCorp. 2009. Stata Statistical Software: Release 11. College Station, TX, USA: StataCorp LP). We enrolled 98 patients (45 men, 53 women) with SCD with a mean age of 26 years (SD 8.8; 14–75). Mean weight and height were 56.9 kg (SD 14.5; 35–124) and 157 cm (SD 9; 140–182), respectively, and mean BP was 110/67 mmHg (SD 13/9). Hemoglobin measurements revealed a mean Ref Hb of 9.2 g/dL (SD 1.5; 5.3–13). The mean pulse CO-oximetry Hb was 10.1 g/dL (SD 2.0; 5.3–14.5) for the first attempt and 9.9 g/dL (SD 1.9; 5.2–14.4) for the second attempt. The correlation coefficient between the Sp1 Hb and Ref Hb was 0.54 (Figure 1). The regression equation of Ref Hb over the Sp1 Hb revealed an intercept of 4.9 (95% CI: 3.6–6.3) with coefficient of 0.42 (95% CI: 0.29–0.55). The R of the model was 29%. The mean difference between Sp1 Hb and the Ref Hb was 0.9 g/dL (SD 1.7; 4.8 to 4.5). There was a very good agreement of the two methods with most points within 1.96 SD of the mean difference as shown in the Bland–Altman plot in Figure 2. In the multivariable linear regression model, male gender (P = 0.042) and Hb level (P = 0.001) were statistically

Intra-operative cell salvage in cardiac surgery may increase platelet transfusion requirements: a cohort study

The cell saver (CS) has been widely utilized in cardiac surgery to reduce red blood cell (RBC) transfusion. We aim at examining its effect on the rate of allogeneic transfusion, morbidity and mortality in our population.

Transfusion therapy and alloimmunization in Thalassemia Intermedia: A 10 year experience at a tertiary care university hospital

BACKGROUND Thalassemia Intermedia (TI) has a wide clinical profile with many patients requiring only occasional transfusions. To prevent alloimmunization, we adopted a policy of issuing phenotype matched red blood cells in 2009. We examined transfusion indications and alloimmunization rate in TI patients. STUDY DESIGN AND METHODS Clinical and blood bank records of 37 TI patients were reviewed. RESULTS 23 Patients required transfusion for pregnancy (26), splenectomy (8) and anemia (11). Since 2009, total of 335 units were transfused with only one antibody developing after transfusing a non-phenotype matched unit. CONCLUSION The commonest indication for blood transfusion was pregnancy. Providing phenotype matched blood has successfully reduced the rate of alloimmunization.

First Implementation of Transfusion Consent Policy in Oman : Audit of compliance from a tertiary care university hospital

OBJECTIVES Transfusions are a common medical intervention. Discussion of the benefits, risks and alternatives with the patient is mandated by many legislations prior to planned transfusions. At the Sultan Qaboos University Hospital (SQUH), Muscat, Oman, a written transfusion consent policy was introduced in March 2014. This was the first time such a policy was implemented in Oman. This study therefore aimed to assess adherence to this policy among different specialties within SQUH. METHODS The medical records of patients who underwent elective transfusions between June and August 2014 were reviewed to assess the presence of transfusion consent forms. If present, the consent forms were examined for completeness of patient, physician and witness information. RESULTS In total, the records of 446 transfused patients (299 adult and 147 paediatric patients) were assessed. Haematology patients accounted for 50% of adult patients and 71% of paediatric patients. Consent was obtained for 75% of adult and 91% of paediatric patients. The highest adherence rate was observed among adult and paediatric haematology specialists (95% and 97%, respectively). Consent forms were correctly filled out with all details provided for 51% and 52% of adult and paediatric patients, respectively. Among inadequately completed forms, the most common error was a lack of witness details (20-25%). CONCLUSION In most cases, the pre-transfusion consent policy was successfully adhered to at SQUH. However, further work is required to ensure full compliance with the consent procedure within different specialties. Implementation of transfusion consent in other hospitals in the country is recommended.

Red Cell Alloimmunization to Rhesus Antigen Among Pregnant Women Attending a Tertiary Care Hospital in Oman.

OBJECTIVES The detection of maternal alloimmunization against red cell antigens is vital in the management of hemolytic disease of the fetus and newborn. We sought to measure the presence of allosensitization to Rhesus D (RhD) antibodies in antenatal women attending a tertiary care hospital and assess the fetal outcome in sensitized women. 
 METHODS We conducted a retrospective review of pregnant Omani women who registered at the Sultan Qaboos University Hospital between June 2011 and June 2013. Pregnant women were tested for ABO blood type and were screened for RhD antigen and antibodies at their first antenatal clinic visit. In women who tested positive for the RhD antibodies, an antibody titer was performed to evaluate the severity of their case. RESULTS Data was available on 1,251 pregnant women who were managed and delivered at Sultan Qaboos University Hospital. The prevalence of RhD negative pregnant women was 7.3%. Blood group O was the most common followed by A, B, and AB. The rate of RhD negative alloimmunization was 10%, and anti-D was the most common antibody detected. There were no stillbirths or neonatal deaths. Postnatal transfusion was necessary for only one baby. CONCLUSIONS The prevalence of RhD negativity was comparable to other Asian countries. Previous RhD alloimmunization and history of miscarriages were the most common maternal medical history.