# Situation: The nurse is assigned to the labor, delivery, and postpartum units of a government hospital. A 25-year-old primigravida at 39 weeks' gestation in early labor has been lying flat on her back for an abdominal examination and fetal monitoring. She becomes dizzy, pale, and sweaty, and her blood pressure falls from 112/70 mmHg to 88/54 mmHg. She has no vaginal bleeding and has received no analgesia or anesthesia. What should the nurse do FIRST?

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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.

A 25-year-old primigravida at 39 weeks' gestation in early labor has been lying flat on her back for an abdominal examination and fetal monitoring. She becomes dizzy, pale, and sweaty, and her blood pressure falls from 112/70 mmHg to 88/54 mmHg. She has no vaginal bleeding and has received no analgesia or anesthesia. What should the nurse do FIRST?

## 보기

1. Increase the rate of her intravenous fluid infusion
2. Turn her onto her left side **✔ 정답**
3. Place her in the Trendelenburg position
4. Give oxygen by face mask at 10 L/min

**정답: 2**

## 해설

In the supine position the heavy uterus compresses the inferior vena cava, reducing venous return, cardiac output, and placental blood flow (supine hypotensive syndrome). Turning her to the left side relieves the compression at once and usually restores blood pressure within minutes. Other measures are needed only if hypotension persists after repositioning.

## 심화 해설

Clinical situation
A primigravida at term develops dizziness, pallor, diaphoresis, and hypotension while lying supine. The uterus compresses the inferior vena cava, reducing venous return and cardiac output. The first action is to relieve that compression by turning her onto her left side.

Why left lateral positioning comes first
In late pregnancy, the gravid uterus can compress the inferior vena cava when the woman lies flat on her back. This reduces venous return to the right heart, lowers cardiac output, and decreases placental perfusion. The resulting clinical picture is supine hypotensive syndrome, also called aortocaval compression syndrome. Turning the woman to the left side shifts the uterus off the vena cava, restoring venous return and blood pressure within minutes [1][2].

Pathophysiology in simple terms
The inferior vena cava lies slightly to the right of the spine. In the supine position, the heavy term uterus can press directly on this thin-walled vessel. Reduced venous return leads to decreased preload, decreased stroke volume, and a fall in cardiac output, which manifests as hypotension and reflex symptoms such as dizziness, pallor, and sweating. The aorta may also be compressed, further reducing uteroplacental blood flow [2][4].

Why the other options are not first

| Intervention | Why it is not the first action |
| --- | --- |
| Increase IV fluid rate | Fluid boluses can support preload, but they do not remove the mechanical obstruction. The uterus is still compressing the vena cava, so the underlying cause remains. |
| Trendelenburg position | This position does not reliably relieve vena caval compression and may worsen respiratory mechanics. Left lateral tilt or full left lateral positioning is the standard maneuver [1]. |
| Oxygen 10 L/min by mask | Oxygen may be helpful if hypoxia or fetal distress is present, but it does not correct the primary problem of reduced venous return from caval compression. |

Clinical recognition and monitoring
Symptoms can range from vague complaints to severe hypotension, loss of consciousness, and fetal depression [2]. A drop in systolic blood pressure of 15–30 mmHg or a heart rate increase of 20 bpm with or without symptoms may indicate supine hypotensive syndrome [4]. In this case, the blood pressure fell from 112/70 mmHg to 88/54 mmHg, a systolic drop of 24 mmHg, which fits the definition.

Key point! The first nursing action is always to remove the cause: reposition the woman off her back. A left lateral position or at least a 15° left lateral tilt is the standard immediate intervention for suspected supine hypotensive syndrome. [1][2]

Watch out! Do not delay repositioning to start IV fluids or oxygen. Those are adjuncts to consider only if hypotension persists after the uterus is shifted off the vena cava.

Application to the labor and delivery unit
During abdominal examinations, fetal monitoring, or any procedure requiring supine positioning in late pregnancy, the nurse should anticipate the risk of aortocaval compression. Routine use of a left lateral tilt or a wedge under the right hip can prevent supine hypotensive syndrome before symptoms develop. If symptoms appear, immediate left lateral positioning remains the priority because it directly addresses the mechanical obstruction [1][2].
References (research sources)

- [1]Supine hypotensive syndrome of pregnancy: A review of current knowledge.Research articleMassoth C, Chappell D, Kranke P, Wenk M (2022) · DOI: 10.1097/EJA.0000000000001554

- [2][Aortocaval compression syndrome].Research articleKiefer RT, Ploppa A, Dieterich HJ (2003) · DOI: 10.1007/s00101-003-0596-6

- [4]Hemodynamic changes in women with symptoms of supine hypotensive syndrome.Research articleHumphries A, Mirjalili SA, Tarr GP, Thompson JMD, Stone P (2020) · DOI: 10.1111/aogs.13789

## 임상 시나리오

Supine Hypotensive Syndrome in LaborImmediate left lateral positioning for vena cava compression
In late pregnancy, the gravid uterus compresses the inferior vena cava when the patient lies flat. This reduces venous return, cardiac output, and placental perfusion, causing dizziness, pallor, diaphoresis, and a fall in blood pressure from 112/70 mmHg to 88/54 mmHg.

The first action is to turn the patient onto her left side. This shifts the uterus off the vena cava, restoring venous return and blood pressure usually within minutes. Left lateral positioning is the definitive correction for the mechanical obstruction.

CautionDo not delay repositioning to start IV fluids, apply oxygen, or place the patient in Trendelenburg. These measures are supportive only and do not relieve the aortocaval compression. If hypotension persists after left lateral positioning, then escalate with fluid bolus and oxygen.

## 핵심 개념

- **Supine hypotensive syndrome** — Hypotension and symptoms caused by compression of the inferior vena cava by the gravid uterus in the supine position, reducing venous return and cardiac output.
- **Aortocaval compression** — Compression of the aorta and inferior vena cava by the pregnant uterus, decreasing venous return and uteroplacental blood flow.
- **Left lateral position** — Positioning the pregnant patient on her left side to shift the uterus off the vena cava and restore venous return.
- **Venous return** — The flow of blood back to the right atrium; reduced by vena cava compression, leading to decreased preload and cardiac output.
- **Preload** — The degree of ventricular stretch at end-diastole; decreased when venous return is impaired, lowering stroke volume.

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