# Situation: The nurse is assigned to the labor, delivery, and postpartum units of a government hospital. After a vaginal birth, the nurse quantifies the client's blood loss by measurement and weight. The calibrated under-buttock drape holds 600 mL of fluid, of which 250 mL was amniotic fluid collected before the birth of the baby. Five soaked perineal pads weigh 610 g in total, and each dry pad weighs 22 g. Using 1 g = 1 mL, what is her cumulative quantified blood loss in milliliters? (No rounding is needed.)

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> subject: Nursing Practice II — Maternal and Child Health Nursing

## 문제

Situation: The nurse is assigned to the labor, delivery, and postpartum units of a government hospital.

After a vaginal birth, the nurse quantifies the client's blood loss by measurement and weight. The calibrated under-buttock drape holds 600 mL of fluid, of which 250 mL was amniotic fluid collected before the birth of the baby. Five soaked perineal pads weigh 610 g in total, and each dry pad weighs 22 g. Using 1 g = 1 mL, what is her cumulative quantified blood loss in milliliters? (No rounding is needed.)

## 보기

1. 960 mL
2. 1,100 mL
3. 1,210 mL
4. 850 mL **✔ 정답**

**정답: 4**

## 해설

Drape blood = 600 mL − 250 mL amniotic fluid = 350 mL. Pad blood = 610 g − (5 × 22 g) = 610 − 110 = 500 g, which equals 500 mL. Total quantified blood loss = 350 + 500 = 850 mL. Weighing pads and subtracting amniotic fluid gives a far more accurate measure than visual estimation.

## 심화 해설

Core Calculation

The cumulative quantified blood loss (QBL) is determined by combining measured fluid from the calibrated drape and the weight of saturated perineal pads, after subtracting non-blood fluid.

Drape blood loss: The drape contains 600 mL of total fluid. Of this, 250 mL is amniotic fluid collected before delivery. Therefore, the blood component in the drape is 600 − 250 = 350 mL.

Pad blood loss: Five soaked pads weigh 610 g total. Each dry pad weighs 22 g, so the dry weight of five pads is 5 × 22 = 110 g. The net weight of blood is 610 − 110 = 500 g. Using the conversion 1 g = 1 mL, this equals 500 mL.

Total QBL = 350 mL (drape) + 500 mL (pads) = 850 mL.

Key point! Amniotic fluid must be subtracted from the drape volume, and the dry weight of each pad must be subtracted from the total pad weight before converting grams to milliliters.

Why Objective Measurement Matters

Postpartum hemorrhage (PPH) remains a leading cause of maternal mortality worldwide, and early recognition depends heavily on accurate blood loss assessment [3]. Visual estimation—the traditional method—is highly inaccurate and frequently leads to underdiagnosis of PPH, delaying critical interventions [3]. This is why quantitative methods, such as the calibrated drape plus pad weighing used in this scenario, are now recommended.

Quantitative blood loss (QBL) has been shown to improve detection of PPH compared with graduated estimated blood loss (EBL) in spontaneous vaginal deliveries [1]. In a prospective observational study, QBL calculated by nurses using volumetric and gravimetric techniques provided more reliable prediction of clinical outcomes than provider estimates [1]. The FIGO guideline explicitly recommends objective measurement of blood loss after birth for early PPH detection [3].

Step-by-Step Gravimetric Method

The pad-weighing portion uses a gravimetric technique: blood volume is inferred from weight because 1 mL of blood weighs approximately 1 g. The calculation requires knowing the dry weight of each pad type used, since pads absorb variable amounts depending on their material and size.

| Step | Action | Result |
| --- | --- | --- |
| 1 | Record total drape fluid | 600 mL |
| 2 | Subtract amniotic fluid | 600 − 250 = 350 mL |
| 3 | Weigh all soaked pads | 610 g |
| 4 | Subtract dry pad weight (5 × 22 g) | 610 − 110 = 500 g |
| 5 | Convert grams to milliliters | 500 g = 500 mL |
| 6 | Add drape and pad blood | 350 + 500 = 850 mL |

Watch out! A common error is forgetting to subtract the dry pad weight before converting to milliliters. Another is failing to subtract amniotic fluid from the drape, which would falsely elevate the blood loss estimate.

Clinical Significance of the 850 mL Result

The calculated QBL of 850 mL is below the traditional threshold for PPH after vaginal delivery (500 mL), but it is still a substantial loss that warrants close monitoring. However, the clinical significance of QBL extends beyond a single threshold. Studies comparing QBL with calculated blood loss based on laboratory parameters have noted that volumetric techniques may be partly subjective and potentially biased by amniotic fluid or missed out-of-bag losses . This is precisely why subtracting amniotic fluid—as done in this scenario—is essential for accuracy.

A quantitative real-time measurement system validated in over 900 patients demonstrated feasibility and precision during both vaginal delivery and cesarean section when compared with a hemoglobin-based formula for blood loss . This supports the routine use of objective measurement in everyday clinical settings, not just research protocols.

The combination of calibrated drape measurement and gravimetric pad weighing provides a more accurate, reproducible QBL than visual estimation alone. This allows earlier recognition of excessive bleeding and more timely initiation of PPH protocols, which is critical for reducing maternal morbidity and mortality [3].References (research sources)

- [1]Performance of quantitative and graduated estimated blood loss in detection of postpartum hemorrhage after spontaneous vaginal delivery.Research articleWhite A, Burns RN, Pruszynski JE, Ravindra D, Montgomery T, Fin KX, Anyaehie B, Duryea EL. (2026) · DOI: 10.1002/pmf2.70385

- [3]FIGO recommendations on objective measurement of blood loss after birth for early detection of postpartum hemorrhage.GuidelineBegum F, Nieto-Calvache AJ, Schlembach D, Hofmyer J, Palacios-Jaraquemada J, Bhardwaj A, Suarez MA, Burgos-Luna JM, Beyeza-Kashesya J, Ubom AE, Wright A, FIGO Committee on Childbirth and PPH. (2025) · DOI: 10.1002/ijgo.70523

## 임상 시나리오

Quantified Blood Loss CalculationDrape + Pad Weighing Method
Subtract amniotic fluid from the drape volume first: 600 mL − 250 mL = 350 mL blood.

For pads, subtract dry pad weight: 610 g − (5 × 22 g) = 500 g = 500 mL.

Total QBL = 350 mL + 500 mL = 850 mL.

CautionNever add amniotic fluid to blood loss, and always subtract the dry weight of every pad before converting grams to milliliters.

## 핵심 개념

- **Quantitative blood loss (QBL)** — Objective measurement of postpartum blood loss using calibrated drapes and pad weighing, more accurate than visual estimation
- **Calibrated under-buttock drape** — A graduated collection device placed under the patient during delivery to measure fluid loss
- **Amniotic fluid subtraction** — Removing pre-delivery amniotic fluid volume from total drape fluid to isolate blood component
- **Dry pad weight** — Baseline weight of an unused perineal pad, subtracted from soaked pad weight to calculate net blood weight
- **Postpartum hemorrhage (PPH)** — Excessive bleeding after childbirth, a leading cause of maternal mortality requiring accurate blood loss assessment

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