Precise estimation of postpartum haemorrhage: difficulties and importance.

Abstract

The accepted definition of postpartum haemorrhage is an estimated blood loss of at least 500 ml. after vaginal delivery. Estimation of blood loss is often unreliable, for few attendants have a clear appreciation of the appearance of 500 ml. of blood soaked into linen and the other accoutrements of delivery. Because of the failure to recognize the extent of haemorrhage, its true importance in maternal morbidity and mortality tends to be missed. Several methods have been used in attempts to measure blood loss accurately. Gatch and Little (1924) extracted haemoglobin and measured it as acid haematin by photometric comparison with a series of acid haematin solutions prepared by diluting the patient's venous blood. Pilcher and Sheard (1937) Controls.-(1) Five samples of fresh blood of known haemoglobin content and varying in volume between 100 and 300 ml. were allowed to clot in bins containing linen fabrics. The haemoglobin was recovered from each with errors of less than 2 %. (2) An excess of calcium ions was added to known quantities of haemoglobin in six samples of old stored blood varying in volume between 400 and 1,000 ml. These were spilt on the floor and on to fabrics, and again the errors of recovery were less than 2%. (3) Solutions of liquor amnii and of meconium in concentrations greater than would occur in the solution in the washing-machine bowl were not found to cause measurable absorption in the oxyhaemoglobin wave band. Determination of the Significance of the LossesThe blood losses recorded at the time of delivery were compared with the subsequent measurements.

Association of Blood Loss during Delivery to B-Hemoglobin

“…Iron supplementation in the puerperium has attracted far less interest than during pregnancy [1,2], One reason for this may be that it is relatively easy to estimate the iron requirement during pregnancy: it is appropriate to corre late the requirement to both fetal need and maternal well being [3], On the other hand, intrapartum hemorrhage is much more difficult to estimate [4,5], On average, blood loss during delivery is 2-300 ml [1], but can amount to several liters.…”

Validation of a Laboratory Method of Measuring Postpartum Blood Loss

“…Laboratory methods of measurement of blood loss are known to be a more accurate estimate of actual blood loss than visual estimation [1][2][3]. For scientific work involving a small number of cases, especially if blood loss was one of the main outcome parameters, laboratory methods, though cumbersome, are necessary.…”

“…The error in each case was less than 10% with an intraclass correlation coefficient of almost 1. Visual estimation of blood loss in the postpartum period is well known to be inaccurate [1][2][3]. In research work, indirect parameters are used to calculate the amount of blood loss.…”

“…These include clinical parameters like change in pulse and blood pressure, need for further oxytocics and need for blood transfusion, as well as laboratory parameters like drop in haemoglobin level. Laboratory methods, although more cumbersome to perform, are known to give more accurate measurements of blood loss [1][2][3].We had adapted a colorimetric method of measurement of menstrual blood loss described by Newton et al[4] in order to measure blood loss in the third stage of labour. This study evaluates the accuracy of the method used in quantifying blood loss postpartum by absorbing a known amount of blood collected in a bottle onto sanitary pads and absorbent paper towels.…”

Análise da hemorragia no parto vaginal pelos índices de eritrócitos e hematócrito

“…(4) Since 1960, reports have shown a discrepancy between blood loss determined by visual examination and by objective techniques at delivery. (5)(6)(7)(8) Methods used to assess blood loss include use of calibrated recipients and laboratory techniques to determine plasma volume and red blood cells before and after delivery using radioisotope labels. (8,9) Mean blood loss during vaginal delivery ranges from 197 ml to 505 ml, and it can be influenced by the assessment method.…”