Résumé
Background: Acute Normovolemic Hemodilution (ANH) and autologous transfusion can mitigate the harmful effects of banked blood intraoperatively. This study was planned to evaluate its effects on perioperative transfusion requirement, hemodynamic stability and safety profile.Methods: Hundred patients were randomized to Group 1, where assigned patients received ANH and autologous transfusion after hemostasis; and Group II where assigned patients received homologous transfusion. In group I, 350 to 700 ml of patient's blood was collected before induction of anaesthesia and was kept in the operation theatre at room temperature. This was followed by rapid infusion of calculated Hetastarch. Intraoperative blood loss, amount of transfused blood, serial haemoglobin (Hb) assessment, and change in hemodynamics were carefully monitored. The blood was reinfused once hemostasis was secured at the end of surgery.Results: It was observed that hemodynamic stability was maintained in both the groups during and after haemodilution. There was no significant change in bleeding and clotting time due to haemodilution. The mean intra-operative blood loss in both groups was comparable. 350 mL and 700 mL blood withdrawn in 27 and 23 patients and 500mL and 1000 mL HES infused respectively. There was an average fall in the mean Hb level by 1.74 gm % and in the mean haematocrit (Hct) level by 6.4 % after haemodilution. The mean 12th and 24th hour Hb and Hct levels were comparable. The requirement of homologous blood transfusion in group I was significantly low (p<0.0001). Need for homologous transfusion was 0.72 per patient treated in the Group I.Conclusions: Acute normovolemic hemodilution is a simple, safe and effective modality to reduce perioperative transfusion of banked blood and should be considered in patients undergoing surgical procedures where major blood loss is expected.
Résumé
Background: In critically ill patients in the intensive care unit (ICU), early aggressive fluid replacement is the cornerstone of resuscitation. Traditionally employed static measures of fluid responsiveness have a poor predictive value. It is therefore imperative to employ dynamic measures of fluid responsiveness that take into account the heart lung interactions in the mechanically ventilated patients. The main objective of this study was to evaluate the reliability of one such non-invasive dynamic index: Plethysmographic variability index (PVI) compared to the widely employed Inferior vena cava distensibility index (dIVC).Methods: Seventy-six adult patients admitted at a tertiary care mixed ICU, who developed hypotension (MAP<65mmHg), were included in the study. PVI was recorded using the MASIMO-7 monitor and dIVC measurements done using Terason ultrasound. Based on the dIVC measurement threshold of 18%, the patients were classified into volume responders and non-responders. The hemodynamic, PVI and dIVC measurements were recorded at pre specified time points following a fluid challenge of 20 ml/kg crystalloid infusion.Results: Baseline PVI values were significantly higher in the responders (22.3±8.2) compared to non-responders (10.1±2.9) (p<0.001) and showed a declining trend at all time points in the responders. Similar declining trend was observed in the dIVC measurements. Overall, the Pearson correlation graph showed strong correlation between dIVC and PVI values at all time points (r=0.678, p=0.001). The ROC curve between the dIVC and PVI values revealed that Baseline PVI (Pre PVI) >15.5% discriminated between responders and non-responders with a 90.2% sensitivity and 75% specificity with an AUC of 0.84 (0.72-0.96) (p<0.001).Conclusions: There is good correlation between PVI values and measured dIVC values at baseline and following a fluid challenge. Thus, PVI may be an acceptable, real time, continuous, surrogate measure of fluid responsiveness in critically ill patients.