Valerie Hill - Surrounding Labour

FHR

 The average FHR at term is 110-160BPM, with an average of 160BPM at 20 weeks. It may accelerate or decel occasionally due to stress. As the SNS matures, FHR goes down.

Fetal Respiration

• Fetal lung fluid is cleared from the fetal lungs as the newborn is born

• Fetal oxygen pressure decreases, and CO2 pressure increases

• Ph and bicarb decrease. 

• Respiratory movements decrease during labor

CV Changes in Mom During Labour

• Cardiac output is increased during labour and peaks about 10-30 minutes after birth and returns to baseline 1 hour after birth.

• BP increases during contractions due to blood being shunted away from the uterus, though BP is normal outside of contractions.

• Supine hypotension may occur due to the uterus pressing down on large vessels such as the vena cava and aorta.

Renal Changes During Labour

People may have trouble peeing. Proteinuria up to +1 is normal due to muscle breakdown from work of labor.

GI Changes During Labour

: GI motility decreased. N&V common. Patients may poop

Endocrine Changes During Labour

• Decreased progesterone. Increased estrogen, prostaglandins and oxy. Bg may decrease. 

When are Patients Encouraged to Come to the Hospital for labour?

First time moms are instructed to come to the hospital when contractions are 4-5mins apart and last 1min in length occurring for approx 1 hour, or when they are unable to cope at home. Multiparous patients are encouraged to come when contractions are 5 minutes apart or if they’re unable to cope.

COAT Acronym

When the patient comes into the hospital, and has discharge that may be amniotic fluid we use the COAT acronym to remember what to ask about the discharge. Color, odor, amount, and time.

Iv Fluid Therapy During Labour

IV Fluid Therapy not recommended during labor. Patients especially should not be given IV glucose as this results in fetal hyperglycemia followed by hypoglycemia, or even newborn tachypnea.

How Often Should Laboring Patients Void

Patients should be encouraged to void every 2 hours.

Crowning

Crowning is when the widest part of the head distends the vulva

When Should the Cord be Cut?

The cord should not be cut until 1-3 mins after birth or until it stops pulsating.

GBS

• At 35-37 weeks a vaginal rectal swab is done to screen for GBS.

• GBS may be a part of normal vaginal flora, however, it can cause the newborn to have a GBS infection through vertical transmission

• To decrease the risk of newborn GBS, IV antibiotics (penicillin G 5millionU loading dose and then 2.5million units every 4 hours till birth) should be offered to all laboring patients who test positive for GBS. This is not recommended before a c section or if ROM has not occurred. For a newborn to be considered treated at least one dose of antibiotics must be recieved 4 hours prior to birth

HSV Management during Labour

C Section recommended within 4 hours if the patient is experiencing prodromal symptoms or has lesions.

Nitrazine Test

Collect fluid from deep in the vagina (perhaps during a speculum exam), on a nitrazine tipped sheet. This will show pH. A blueish/alkaline/basic result means membranes are probably ruptured

Fern Pattern

Spread a drop of fluid from the vagina on a clear glass slide and examine under a microscope. If it looks like ferns membranes are probably ruptured.

chorioamnionitis

After membranes are ruptured, there is a risk of an infection called chorioamnionitis, which is when microorganisms from the vagina ascend into the uterus

Frequency of Contractions Definition

• The number of contractions in a 10 min period averaged out over a 30 min window

intensity of Contractions Definition

The palpable strength of a contraction at its peak

Duration of Contractions Definiton

• The time that elapses between the onset and the end of a contraction in seconds

Resting Tone

The tension in the uterine muscle between contractions.

Leopold Maneuvers

• Patient lies on their back while abdomen is palpated

• Assesses the number of fetuses, presenting part, fetal lie and attitude, degree of descent, expected location of the maximum intensity of the FHR on the patient's abdomen (usually directly over the fetus back).

FHR, Where to hear and how often?

• In the vertex position, the FHR is usually heard in the LLQ or RLQ of the patient's abdomen. 

• In breach FHR is heard above the umbilicus

• Should be assessed every 5-15 mins. Usually a position change resolves most abnormalities.

How do We Know the Second Stage of Labour has Begun?

• The only certain objective sign that the second stage of labor has begun is the inability to feel the cervix on vaginal exam

How to Know if the 2nd Stage of Labour is Going on for Too Long?

• Guidelines for if the second stage is too long is 3 hours (4 with anesthesia) in nulliparous patients, and 2 hours (3 with anesthesia), in multiparous patients.

• Patients should not to prolonged breath holding/valsava when pushing

Perineal Lacerations (First-Fourth Degree)

• First Degree: Laceration extends through the skin and structures superficial to muscles

• Second Degree: Laceration extends to perineal muscles

• Third Degree: laceration extends to anal sphincter muscle

• Fourth Degree: Laceration that goes to the rectal mucosa

How long does the 3rd stage of labour last and how is it managed?

• Placenta is almost always out in 15 mins, but after 30 mins if it still isn’t out that requires more urgency.

• Active management of the third stage with oxytocic drugs is recommended to passive management.

Visceral Pain during Labour

• Generated from cervical changes, pressure and traction on adjacent structures, and uterine ischemia. Felt in the lower portion of the abdomen. 

referred Pain During Labour

• Pain that originates in the uterus, radiates to surrounding structures. 

Somatic Pain During Labour

During the second stage of labor. Intense, sharp, burning and well localized pain. Caused by distension and traction of the peritoneum during contractions, pressure against the bladder and rectum, stretching and distension of the perineal tissues, lacerations of soft tissue.

Beta Endorphins

The body releases beta endorphins, which are endogenous opioids released by the pituitary that help us cope with pain during the labor process. They also cause feelings of euphoria. Beta endorphins are increased in pregnancy.

How Anxiety Affects Labour

Excessive anxiety releases catecholamines → Activates SNS increasing muscle tension → Contraction effectiveness decreased and pain increased → More anxiety

Gate Control Theory of Pain

• Using physical and cognitive distraction techniques is thought to bring different stimuli to the spinal cord and “Close the gates” for labor pain sensations, thus helping relieve/distract from pain

• Techniques like efflurage (light massage) activate the gate control mechanism.

4 Types of Opioid Agonist Analgesics During Labour

• Morphine may be used, but lack of efficacy at non-sedating doses and adverse effects have decreased use

• Meperidine must not be used as it sedates the fetus and cannot be reversed with narcan.

• Fentanyl may be used but it has a very short life. It also crosses the placenta rapidly.

• Remifentanil is even faster and shorter so it may be used by PCA pumps. Crosses placenta but rapidly metabolized by the fetus.

Opioid Agonosts Antagonists During Labour

• Agonists at kappa and antagonists at Mu

• Nalbuphine can be used as it doesn’t cause respiratory depression. It also has a ceiling effect for respiratory depression. Not suitable for patients with an opioid dependence

Nerve Blocks During Labour

• The suffix caine helps identify a local anesthetic.

• Pudendal nerve blocks are useful for episiotomies and sutures. Very effective and safe. Injected transvaginally.

Spinal Anesthesia

An anesthetic solution is injected in L3, 4 or 5 into the subarachnoid space. May cause high spinal or hypotension in mom. Doesn’t usually affect the baby.

Epidural

• Injection in L4 or 5 into the epidural space. Highly effective. May increase labor length, limit movement, cause fever, or cause orthostatic hypotension. Can cause a high spinal if injected in the wrong space.

• May cause postdural puncture/spinal headache if the dura mater is punctured while giving an epidural, which results in CSF leaking and causing a headache when the patient presumes an upright position. Can be managed with oral analgesics and methylxanthines, but the best treatment is blood patch.

• Epidurals/Spinals can be inserted with ONLY opioids. This allows the patients to move around, and feel contractions but not pain which allows for better pushing.

Combined Spinal Epidural Anesthesia

This is an epidural that also has a tube in the spinal space. This allows medications to be put into the spinal space for rapid relief of pain, but the epidural space is also open if patients need more. May cause itchiness, retention, nausea and respiratory depression. Associated with a greater risk of FHR abnormalities than a normal epidural.

IV Meds for Pain

• Meds such as fentanyl and nalbuphine are given through IV during a contraction to provide pain relief to mom but also decrease fetal exposure (due to contracted BVs)