Alterations Intrapartum

Medication Dosage Calculation Practice

• Medication Order: Begin Oxytocin $2\,mU/min$ IV by continuous infusion.

• Available Medication: Oxytocin $15\,U$ in $250\,mL$ $D5W$.

• Calculation Goal: Determine the rate in $mL/hr$ for the infusion pump.

• Step 1: Convert units: $15\,U = 15,000\,mU$.

• Step 2: Determine concentration: $\frac{15,000\,mU}{250\,mL} = 60\,mU/mL$.

• Step 3: Calculate flow rate in minutes: $\frac{2\,mU/min}{60\,mU/mL} = \frac{1}{30}\,mL/min$.

• Step 4: Convert to hourly rate: $\frac{1}{30}\,mL/min \times 60\,min/hr = 2\,mL/hr$.

• Calculated Pump Setting: $2\,mL/hr$.

Understanding Labor Induction and Augmentation

• Induction of Labor: The deliberate stimulation of uterine contractions (UC) before the onset of spontaneous labor.

• Augmentation of Labor: The stimulation of ineffective uterine contractions (UCs) after spontaneous labor has already commenced.

• Factors to Consider in Induction and Augmentation:

  • Parity: Multiparous patients often respond more quickly to induction and have a lower risk of cesarean birth. Nulliparas may require more extensive cervical ripening and a longer induction duration.

  • Status of Membranes: Ruptured membranes increase the risk of infection and limit method options. Intact membranes allow for prostaglandins or mechanical ripening, whereas ruptured membranes may prompt the immediate use of oxytocin or amniotomy.

  • Status of the Cervix: Determined by the Bishop Score. An unfavorable cervix ($<6$) may require ripening agents, while a favorable cervix ($>8$) can proceed directly to oxytocin or artificial rupture of membranes (AROM).

  • History of Previous Cesarean Births: This history raises concerns regarding uterine rupture, especially when certain induction agents are used. Misoprostol should be avoided in patients seeking a Vaginal Birth After Cesarean (VBAC). Mechanical methods or cautious oxytocin use with continuous monitoring are preferred.

Features of Induction vs. Augmentation

• Labor Induction:

  • Definition: Initiating labor artificially before it begins naturally.

  • Usage Context: No contractions or cervical changes have occurred yet.

  • Common Reasons: Post-term pregnancy, preeclampsia, fetal concerns.

  • Methods: Cervical ripening agents (e.g., misoprostol), oxytocin, membrane sweep, amniotomy.

  • Goal: To start uterine contractions and cervical dilation.

  • Risks: Uterine hyperstimulation, failed induction, cesarean section.

• Labor Augmentation:

  • Definition: Enhancing or speeding up labor that has already started.

  • Usage Context: Labor has started but is slow, stalled, or ineffective.

  • Common Reasons: Weak contractions, prolonged labor, failure to progress.

  • Methods: Oxytocin, amniotomy, position changes, hydration.

  • Goal: To strengthen or regulate contractions to aid progression.

  • Risks: Increased intervention cascade, uterine rupture (rare).

The Bishop Scoring System

• Purpose: The most commonly used method to rate the readiness of the cervix for induction of labor based on five measurements from a pelvic examination.

• Readiness Threshold: If the score is less than $6$, the cervix is considered "not ripe," and ripening agents should be used before labor induction.

• Scoring Factors:

  • Dilation (cm):

    • $0\,pts$: Closed

    • $1\,pt$: $1-2\,cm$

    • $2\,pts$: $3-4\,cm$

    • $3\,pts$: $5-6\,cm$

  • Position of Cervix:

    • $0\,pts$: Posterior

    • $1\,pt$: Midposition

    • $2\,pts$: Anterior

  • Effacement (%):

    • $0\,pts$: $0-30\%$

    • $1\,pt$: $40-50\%$

    • $2\,pts$: $60-70\%$

    • $3\,pts$: $80\%$

  • Station (scale of -3 to +3):

    • $0\,pts$: $-3$

    • $1\,pt$: $-2$

    • $2\,pts$: $-1, 0$

    • $3\,pts$: $+1, +2$

  • Cervical Consistency:

    • $0\,pts$: Firm

    • $1\,pt$: Medium

    • $2\,pts$: Soft

Methods and Pharmacological Agents for Labor Management

• Cervical Ripening and Induction Methods:

  • Nonpharmacologic Methods: Often utilized for ripening an "unripe" cervix.

  • Mechanical Methods: Foley catheter or similar device to physically dilate the cervix.

  • Membrane Stripping: A finger is swept against the cervix to release endogenous prostaglandins.

  • Prostaglandins (e.g., Misoprostol, Dinoprostone): Stimulate cervical ripening and uterine contractions for an unfavorable cervix.

  • Amniotomy (AROM): Artificial rupture of membranes to facilitate or speed up labor; often combined with oxytocin.

  • Oxytocin (Pitocin): Used via IV drip once the cervix is ripe to stimulate and regulate contractions. It must be titrated via a pump using the port closest to the client.

• Intrapartum Medications:

  • Oxytocics (Pitocin): Stimulates uterine smooth muscle contractions via oxytocin receptors. Used for labor induction, augmentation, and postpartum hemorrhage.

  • Tocolytics (Terbutaline): A Beta-2 agonist that relaxes uterine smooth muscle. Used to temporarily halt preterm labor or resolve uterine tachysystole.

Nursing Management of Oxytocin Infusion and Uterine Tachysystole

• Oxytocin Nursing Assessments:

  • Assess and document maternal vital signs, Fetal Heart Rate (FHR), and UCs every $15\,minutes$ during the first stage of labor.

  • Assess every $5\,minutes$ during the second stage.

  • Assess Intake and Output (I&O).

  • Discontinue oxytocin immediately if tachysystole or a non-reassuring FHR occurs.

• Signs of Uterine Tachysystole (Hyperstimulation):

  • $5$ or more contractions in a $10-minute$ period.

  • A single contraction lasting $2\,minutes$ or longer.

  • Uterine contractions occurring within $1\,minute$ of each other.

• Interventions for Tachysystole or Non-reassuring FHR:

  • Stop Oxytocin: Reduces uterine activity and fetal stress.

  • Repositioning: Place the patient in the left lateral position to improve uteroplacental perfusion or side-to-side/knee-chest to relieve cord compression.

  • IV Fluids: Increase fluids to boost maternal blood volume and placental perfusion.

  • Oxygen: Administer $10\,L/min$ via nonrebreather (NRB) face mask.

  • Notify Provider: Consult the healthcare provider immediately.

  • Tocolytics: Administer Terbutaline if ordered to relax the uterus.

  • Monitoring: Initiate continuous electronic fetal monitoring; consider internal monitors (IUPC or scalp electrode) if appropriate.

Artificial Rupture of Membranes (AROM)

• Advantages:

  • Facilitates or speeds up labor by releasing prostaglandins and enhancing contractions.

  • Allows for internal monitoring (FSE or IUPC).

  • Enables assessment of amniotic fluid (color, odor, volume, meconium).

• Disadvantages and Risks:

  • Infection (Chorioamnionitis): Risk increases if delivery does not occur within $24\,hours$ of rupture.

  • Prolapsed Umbilical Cord: Fluid gush may displace the cord, especially if the fetal head is not engaged.

  • Cord Compression: Loss of fluid cushioning can lead to variable decelerations.

  • Increased Pain: Contractions may intensify rapidly.

  • Limited Mobility: Typically requires continuous monitoring.

Assisted Vaginal Delivery and Cesarean Birth

• Assisted Delivery Tools:

  • Vacuum Extractor: Cuplike suction attached to the fetal head to assist descent.

  • Forceps: Stainless-steel tongs with rounded edges that fit around the head.

• Cesarean Section Overview:

  • An operative procedure where the fetus is delivered through an abdominal wall incision.

  • The current rate in the United States is approximately $32\%$.

  • VBAC (Vaginal Birth After Cesarean) has a success rate of approximately $60\%\text{ to }80\%$.

  • Incision Types: Low transverse, low vertical, or classical incision.

  • Uterine Rupture Risk: Symptomatic disruption of uterine layers or previous scar. Incidence is approximately $1\%$. Causes include separation of a classic cesarean scar and uterine trauma.

• Nursing Care for Cesarean Birth:

  • Preoperative: Knowledge assessment, FHR/VS check, wedge under hip, Foley catheter insertion, NPO status, IV fluids, sequential compression devices (SCD), and oral antacid.

  • Intraoperative: Positioning, monitoring FHR and vitals, documenting I&O, and performing instrument/sponge counts.

  • Postoperative: Monitor lochia (amount/characteristics), assess fundus, check lung/bowel sounds, manage pain, facilitate breastfeeding, and assess bonding.

  • Post-op Complications: Hemorrhage, Deep Vein Thrombosis (DVT), Pulmonary Embolism (PE), hematuria (bladder trauma), and infection (incision, bladder, endometrium).

Obstetric Emergencies

Placental Abruption (Placentae Abruptio)

• Definition: Premature separation of a normally implanted placenta leading to hemorrhage.

• Presentation: Dark red bleeding, painful, board-like/rigid abdomen.

• Classification:

  • Grade I (Mild): Separation with $<500\,mL$ blood loss; normal FHR.

  • Grade II (Moderate): $1000-1500\,mL$ blood loss; abnormal FHR pattern.

  • Grade III (Severe): $>1500\,mL$ blood loss; abnormal FHR or fetal death.

• Risk Factors: Hypertension/preeclampsia, abdominal trauma, cocaine use, smoking, previous abruption, multiple gestation, advanced maternal age ($>35$), short umbilical cord.

• Management: Large bore IV ($16$ or $18$ gauge), position/O2, monitor vitals, monitor for DIC and hypovolemic shock, and prepare for delivery.

Prolapsed Umbilical Cord

• Definition: The cord lies below or alongside the presenting part, leading to compression and compromised circulation.

• Risk Factors: Malpresentation, unengaged presenting part, long cord ($>100\,cm$), polyhydramnios, preterm fetus, or high parity.

• Emergency Treatment:

  • Call for immediate help.

  • Relieve pressure: Knee-chest position or Trendelenburg.

  • Manual elevation: Use a gloved hand to push the presenting part off the cord.

  • Cover exposed cord with sterile saline-soaked gauze (do not handle excessively).

  • Prepare for emergency cesarean section.

Shoulder Dystocia

• Definition: The fetal head is born, but the anterior shoulder cannot pass under the pubic arch.

• Clinical Presentation: "Turtle sign" (head retracts against perineum).

• Interventions:

  • Call for help; lower head of bed.

  • McRoberts Maneuver: Hyperflex maternal thighs to widen the pelvic outlet.

  • Suprapubic Pressure: Apply pressure above the pubic bone to dislodge the shoulder. (Note: Never apply fundal pressure).

• Risks: Brachial plexus damage, fracture, neonatal asphyxia, maternal uterine rupture.

Precipitous Birth

• Definition: Birth occurring within less than $3\,hours$ from the start of regular contractions.

• Nursing Actions: Assist the woman to lie down, apply gentle pressure to the perineum, check for nuchal cord (remove if loose), and cover the infant with a warm blanket immediately.

Questions & Discussion

• Question 1: A nurse is assessing a pregnant client in the second trimester admitted with suspected abruptio placentae. Which finding is expected?

  • Response: C. Uterine tenderness. (Abruption is characterized by painful, dark red bleeding and a rigid abdomen, whereas placenta previa is typically painless with bright red bleeding).

• Question 2: A nurse reviews provider orders for a client in the third trimester with vaginal bleeding and suspected placenta previa. Which order requires clarification?

  • Response: B. Obtain equipment for a manual pelvic examination. (Manual pelvic exams are contraindicated in suspected placenta previa because they can cause severe hemorrhage).

• Question 3: The nurse notes the umbilical cord protruding from the vagina. What is the first nursing action?

  • Response: B. Place the client in knee-chest position. (This uses gravity to shift the fetus off the cord to relieve compression).