Assessment of blood loss


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Assessment of blood loss

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Assessment of blood loss

  1. 1. Assessment of blood loss Prof. Aboubakr elnashar Benha university hospital, Egypt Email: Aboubakr Elnashar
  2. 2. •Visual inspection is inaccurate. In some reports, the amount of blood estimated to have been lost by inspection was half the measured loss. •Clinicians typically underestimate postpartum blood loss by 30%-50% •Importantly, in obstetrics, part or all of the hemorrhage may be concealed. •Clinicians commonly record blood loss using inaccurately low numbers. "How can we teach people to accurately and honestly record blood loss?“ Aboubakr Elnashar
  3. 3. •On average, women lose about 500 cc in a vaginal delivery, 1,000 cc in CS, and 1,500 cc in a cesarean hysterectomy. •The critical area where you want to estimate blood loss is over 2,000 cc, and we almost always underestimate that. By that point, the patient has hypotension, has significant tachycardia, and is in shock. Aboubakr Elnashar
  4. 4. A. Clinical methods Aboubakr Elnashar
  5. 5. 1. BP, HR: •By the time you detect changes in BP or HR suggesting PPH, the woman already has lost 1/3 of her blood volume •Orthostatic hypotension would tell you that the patient has lost 20%-25% of her blood, but if she is sitting or lying down on the delivery table, you're unlikely to detect that symptom. •Hypotension reflects a loss of 30%-35% of blood volume. "Do not wait for hypotension" to treat for PPH "Do not wait to start seeing S and S. Aboubakr Elnashar
  6. 6. 2. Hematocrit: •It needs 4 h for significant changes and 48 h for complete compensation •In acute hemorrhage, the immediate hct may not reflect actual blood loss. •After the loss of 1000 mL, the hct typically falls only 3 volume % in the first hour. •When resuscitation is given with rapid infusion of IV crystalloids, there is rapid equilibration. •During an episode of acute significant hemorrhage, the initial hct is always the highest. This is true whether it is measured in the delivery room, operating room, or recovery room. Aboubakr Elnashar
  7. 7. 3. Urine output •One of the most important "vital signs" to follow in the bleeding patient with obstetrical hemorrhage. •In the absence of diuretics, the rate of urine formation reflects the adequacy of renal perfusion and, in turn, perfusion of other vital organs, because renal blood flow is especially sensitive to changes in blood volume. •Urine flow of at least 30 mL and preferably 60 mL/h should be maintained. •With potentially serious hemorrhage, an indwelling catheter should be inserted to measure urine flow. Aboubakr Elnashar
  8. 8. 4. Weighing packs and correlate with blood loss: Hospital keeps scales in delivery rooms to weigh lap sponges & other materials to estimate blood loss. 1kg soaked swabs: 1000ml 5. Perhaps the easiest method of estimating is to picture a soda can, which would hold about 350 cc of blood. When you look at blood clots or blood in a canister, estimate how many cans of soda are represented, and you'll be close to blood volume lost. "The principle is to recognize volume. Aboubakr Elnashar
  9. 9. 6. Maximum capacity of Swab Small (10x10cm): 60ml Medium (30x30 cm): 140ml Large (45x45 cm): 350ml 7. Floor spill 50 cm diameter: 500ml 75 cm diameter: 1000ml 100 cm diameter: 1500ml 8. Vaginal PPH limited to bed only Unlikely to exceed 1000ml spilling from bed to floor likely to Exceed 1000ml Aboubakr Elnashar
  10. 10. B. Actual blood loss •In the perioperative period clinical estimation of blood loss is inaccurate and alone should not be used to determine the need for red blood cell transfusions. •Poor agreement between the Actual Blood Loss and the estimated blood loss. The 95% confidence intervals (- 719.939 ml to+1265.619 ml) suggest that clinical estimation alone may result in unacceptable under or over transfusions. •In 64% of the cases the blood loss was underestimated. •Clinical estimations of blood loss suffer from large interobserver variability and poor repeatability. Aboubakr Elnashar
  11. 11. •The extent of blood loss and response to transfusion is reflected in the changes in the hct. •This change may be used to calculate the Actual Blood Loss using suitable formulae. Aboubakr Elnashar
  12. 12. The Actual Blood Loss is a modification of the Gross formula: ABL = BV [Hct (i) - Hct (f)]/ Hct (m) Blood Volume=Body Wt in Kgs x 70 mlkg-1 Hct (i), Hct (f) and Hct (m): the initial, final and mean (of the initial and final) Hematocrits respectively. Blood volume Neonates: 85-90ml/ kg body weight Children: 80ml/ kg body weight Adults: 70ml/ kg body weight Aboubakr Elnashar
  13. 13. Calculating blood loss in theatre: 1. Weigh a dry swab. 2. Weigh blood soaked swabs as soon as they are discarded and subtract their dry weight (1ml of blood weighs approximately 1gm). 3. Subtract the weight of empty suction bottles from the filled ones. 4. Estimate blood loss into surgical drapes, together with the pooled blood beneath the patient and onto the floor. 5. Note the volume of irrigation fluids, subtract this volume from the measured blood loss to estimate the final blood loss. Aboubakr Elnashar
  14. 14. The decision to transfuse blood: 1. Percentage method. Calculate the patient’s blood volume. Decide on the percentage of blood volume that could be lost but safely tolerated, depending on the clinical condition of the patient, provided that normovolaemia is maintained (table) Aboubakr Elnashar
  15. 15. Patient condition Health Average Poor Percentage method Acceptable loss of blood volume before transfusion method 30% 20% <10% Haemodilution Hb 7-8g/dl Hct 21-24% 8- 9g/dl 24-27% 10g/dl 30% Aboubakr Elnashar
  16. 16. 2. Haemodilution method. Decide on the lowest acceptable Hb or Haematocrit (Hct) that may be safely tolerated by the patient (table ). Calculate the allowable volume of blood loss that can occur before a blood transfusion becomes necessary. Replace blood loss up to the allowable volume with crystalloid or colloid fluids to maintain normovolaemia. If the allowable blood loss volume is exceeded, further replacement should be with blood. Aboubakr Elnashar
  17. 17. •Whichever method is used, the decision to transfuse will depend on the clinical condition of the patient and their ability to compensate for a reduction in oxygen supply. This is particularly limited in patients with evidence of severe cardiac or respiratory disease or pre- existing anaemia. •The methods described are simple guidelines which must be altered according to the clinical situation. •Further blood loss should be anticipated, particularly postoperatively. •Whenever possible, transfuse blood when surgical bleeding is controlled. This will maximise the benefits of the transfusion. Aboubakr Elnashar
  18. 18. •The American College of Physicians recommended that RBC transfusions should be done unit by unit and the patient should be evaluated between each transfusion. •Excessive intraoperative transfusion and the practice of administering blood without reevaluating the hct in between resulted in 90% of the unnecessary transfusions. •Determination of the hct immediately before administration of each unit would reduce blood consumption by 25%. Aboubakr Elnashar
  19. 19. Recommendation A program to train doctors & nurses to estimate blood loss. Aboubakr Elnashar
  20. 20. Thanks Aboubakr Elnashar