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Obstetrical Anesthesia PowerPoint Presentation

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Description : Check out this medical PowerPoint presentation titled "Obstetrical Anesthesia" by Dr Lindsey Patterson.

This medical PowerPoint presentation talks about Obstetrical anesthesia. Obstetrical anesthesia refers to the specialized field of anesthesiology that focuses on providing pain relief and anesthesia to women during pregnancy, labor, delivery, and postpartum. The aim is to ensure the safety and comfort of both the mother and the baby during the process.

There are various types of obstetrical anesthesia techniques used depending on the stage of labor and delivery, the health status of the mother and the baby, and the personal preferences of the mother. These techniques include:
1. Epidural anesthesia: This involves injecting a local anesthetic and opioid medication into the epidural space of the spine to provide pain relief from contractions during labor and delivery.
2. Spinal anesthesia: This is a similar technique to epidural anesthesia, but involves injecting the medication directly into the cerebrospinal fluid, producing more rapid onset and profound anesthesia, which is suitable for a C-section delivery.
3. General anesthesia: This involves administering medication that induces unconsciousness, which is typically used in emergency situations when other methods are not feasible, or when the mother has a contraindication to regional anesthesia.
4. Combined spinal-epidural (CSE): This is a technique that involves the insertion of a spinal needle followed by placement of an epidural catheter, providing rapid pain relief with the ability to administer additional medication as needed.
5. Local anesthesia: This involves injecting medication directly into the perineum or vulva to provide anesthesia during delivery.

Tags : Obstetrical Anesthesia, pregnancy, child birth labor, delivery, postpartum, Anesthesiology

Published on : Mar 16, 2023 | Views : 1723 | Downloads : 1

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Slide 1-

Obstetrical Anesthesia Dr Lindsey Patterson
Slide 2-

Objectives Overview of maternal physiology Analgesia for labor and delivery Regional anesthesia Anesthesia concerns in the parturient Study MCQs with explanations
Slide 3-

Physiological Changes-CVS Almost all the changes seen are due to high levels of progesterone and include: 35%  Total Blood Volume  heart rate 15 beats/min 40%  CO 30%  SV 15%  SVR 500ml/min  blood flow to uterus  venous return from legs AORTOCAVAL COMPRESSION (mechanical)
Slide 4-

Impact of CVS changes Patients with pre-existing cardiac disease may decompensate either during labor or immediately post delivery. This corresponds to the time of maximal CO Approx 400 – 600ml blood loss occurs at delivery Supine hypotensive syndrome
Slide 5-

Aortocaval Compression
Slide 6-

Physiological Changes - Resp  oxygen consumption ~ 20% (100% in labor) due to increased metabolic rate  minute ventilation ~ 50% (due to increased tidal volume)  arterial pCO2  FRC causing a decrease in oxygen reserves
Slide 7-

Impact of Resp. changes Uptake of inhalational agents is faster Decreased FRC and increased oxygen consumption increase the risk of hyoxia with apnea Preoxygenation prior to GA less effective
Slide 8-

Physiological Changes- Airway Venous engorgement of airway mucosa Edema of airway mucosa Worsening of Mallampati score in labor
Slide 9-

Impact of Airway Changes Trauma to upper airway with suctioning, intubation Increased incidence of difficult/failed intubation x10 Require smaller ETT
Slide 10-

Physiological Changes-CNS Decrease in MAC by 25 – 40% Decreased dose of Local Anesthetic requirement for regional techniques More rapid onset of neural blockade
Slide 11-

Impact of CNS Changes Decreased inhalation anesthetic agent requirements Decreased dose of local anesthetic for same effect Increased risk of local anesthetic toxicity
Slide 12-

Physiological Changes - GIT Increased gastric fluid volume Increased gastric fluid acidity Decreased competency of lower esophageal sphincter
Slide 13-

Impact of GIT Changes Increased risk of aspiration All parturients are a “full stomach” Aspiration prophylaxis recommended for C/S 0.3M Sodium citrate 30 mls po Ranitidine 50mg iv Metoclopramide 10mg iv
Slide 14-

Analgesia for labor and delivery Where is the pain coming from? Is pain bad in labor? Analgesic options
Slide 15-

Pain of childbirth Nociceptive pathways involved T10 – L1 during labor plus S2-S4 for delivery
Slide 16-

Is pain bad in labor? Psychological stress can cause: increased levels of catecholamines hyperventilation These may result in decreased uterine blood flow leading to hypoxia and acidosis in the fetus
Slide 17-

Factors affecting pain perception in labor Mental preparation Family support Medical support Cultural expectations Underlying mental status Parity Size and presentation of the fetus Maternal pelvic anatomy Duration of labor Medications
Slide 18-

Analgesia for labor and delivery Non-medication Inhalational Parenteral Regional
Slide 19-

Analgesia- Non medication options Breathing exercises Autohypnosis Acupuncture White Noise/ Music Massage/ walking TENS Water bath
Slide 20-

Inhalation Medications Nitronox: 50:50 mixture of oxygen and nitrous oxide Low dose Isoflurane in oxygen Advantages: on demand delivery, relatively safe Disadvantages: variable efficacy, nausea, drowsiness, neonatal depression
Slide 21-

Parenteral Medications Narcotics: meperidine, morphine fentanyl Advantages: relatively good analgesia Disadvantages: nausea, vomiting, sedation, neonatal depression (max. 2 hours after meperidine dose), short duration of action
Slide 22-

Regional techniques Epidural, spinal, combined spinal-epidural Advantages: excellent pain control, minimal impact on progress of labor with low doses, less drug transfer to fetus, improved uterine blood flow, decrease in birth trauma e.g. use of forceps, minimal neonatal depression Disadvantages: invasive technique, side effects (hypotension, headache, itching, nausea, urinary retention, limited mobility), nerve damage, infection
Slide 23-

Anesthesia in the parturient General considerations of the parturient undergoing surgery Obstetric surgery
Slide 24-

General considerations Altered physiology as mentioned Risks to the fetus: Effect of the disease process/therapies Possible teratogenicity of anesthetic agents Intraoperative effects on uteroplacental blood flow Increased risk of preterm labor/ risk of abortion
Slide 25-

Maternal considerations Altered physiology Altered response to anesthesia Decrease in MAC Increased sensitivity to neuraxial agents Decreased plasma cholinesterase Decreased protein binding (more free drug) Limited drug information in parturients
Slide 26-

Fetal Considerations Teratogenicity: Limited information due to impracticality of conducting trials with sufficient power Guidelines based on a) effects on reproduction in animals; b) epidemiological surveys of OR personnel; c) studies of pregnancy outcomes in parturient undergoing ante partum surgery
Slide 27-

Nitrous oxide has been shown to have a teratogenic effect in rats during the first trimester No anesthetic agent is a proven teratogen in humans Anesthetic agents deemed safe include: thiopental,morphine, meperidine,fentanyl, succinylcholine, NDMRs Limiting nitrous oxide use but only if hypotension secondary to volatiles can be avoided
Slide 28-

Anesthetic management in the parturient should be directed to: Avoidance of hypoxemia Avoidance of hypotension Avoidance of acidosis Maintain PaCO2 in the normal range for the parturient Minimize effects of aortocaval compression
Slide 29-

Anesthesia for Caesarean Section Preparation Preventing complications Choice of Anesthetic technique Effects on the fetus
Slide 30-

Preparation Premeds: antacid (sodium citrate) IV access and fluid bolus within 30 minutes of operating (avoid glucose containing fluids) Left lateral tilt with wedge under right pelvis Routine Monitors: ECG, NIBP, pulse oximeter, fetal monitoring Additional monitors for GAs: ETCO2, nerve stimulator, temp probe
Slide 31-

Preventing complications Aspiration prophylaxis Detailed airway assessment Fluid resuscitation/left lateral tilt to prevent hypotension Safe practice for placement of neuraxial blocks
Slide 32-

Anesthetic techniques Local infiltration by surgeon Regional anesthesia: spinal, epidural, combined spinal-epidural General anesthesia
Slide 33-

Local Infiltration Rarely performed Patient usually in extremis Surgery must be done via midline incision, gentle retraction, no exteriorization of the uterus Usually done to supplement a regional technique if local anesthetic toxicity not a concern
Slide 34-

Regional: Spinal Anesthesia Simple to perform Rapid onset Single shot technique Profound neural block Technique of choice for uncomplicated elective caesarean sections and in many emergency caesarean sections
Slide 35-

Spinal Anesthesia Potential Complications: Hypotension Headache (rare ~1:100) Backache (temporary ~24hrs) Nausea/vomiting (secondary to BP, narcotics) Neurological damage (very rare) Anaphylaxis (very rare)
Slide 36-

Regional: Epidural Anesthesia More technically challenging Slower onset Used when already placed for labor analgesia Useful in parturient where a slow, controlled onset of block is needed Allows prolongation of block should surgery be complicated
Slide 37-

Epidural Anesthesia Potential Complications: Hypotension Headache (approx 1:100) Transient backache ~24hrs Urinary retention Unintentional spinal injection Intravascular injection of local anesthetic Neurological damage Infection
Slide 38-

Regional: Combined spinal-epidural Used when require the speed and density of a spinal anesthetic with the flexibility of prolonging the block by supplemental increments of local anesthesia via the epidural catheter Complications: as mentioned for spinals and epidurals
Slide 39-

General Anesthesia Used when Patient refuses regional technique Regional technique is contraindicated Emergency C/S when there is inadequate/absent regional analgesia and to delay will cause undue risk to the fetus / mother
Slide 40-

General Anesthesia Complications: Failed intubation Failed ventilation causing death or neurological injury Awareness Aspiration pneumonia
Slide 41-

Anesthesia: Effects on the fetus Avoid hypotension, hypoxia, acidosis, hyperventilation Limit time between uterine incision and delivery to less than 3 minutes Infants exposed to GA have lower Apgar at one minute but no difference at 5 mins No significant alteration in neurobehavioral scores with regional techniques
Slide 42-

MCQ 1. Epidural Anesthesia in Obstetric Practice. Which of the following is false. A. Commonly causes itching B. Can be used to control blood pressure in pre-eclampsia C. Causes uterine relaxation D. Causes urinary retention E. Contributes to the effects of aortocaval compression
Slide 43-

MCQ 1. Epidural Anesthesia in Obstetric Practice… A. Commonly causes itching B. Can be used to control blood pressure in pre-eclampsia C. Causes uterine relaxation D. Causes urinary retention E. Contributes to the effects of aortocaval compression
Slide 44-

Itching is one of the most common side-effects of opioids when delivered in the epidural space. Their use allows for a decreased concentration of local anesthetic whilst maintaining excellent analgesia. Patients have better motor function and retain the ability to push.
Slide 45-

MCQ 2. All of the following are false concerning general anesthesia in the parturient, EXCEPT: A. General anesthesia reduces gastric pH B. MAC is decreased C. It is contra-indicated in patients with a bleeding diathesis D. Is a major cause of overall maternal mortality E. Succinylcholine crosses the placenta
Slide 46-

MCQ 2. All of the following are false concerning general anesthesia in the parturient, EXCEPT: A. General anesthesia reduces gastric pH B. MAC is decreased C. It is contra-indicated in patients with a bleeding diathesis D. Is a major cause of overall maternal mortality E. Succinylcholine crosses the placenta
Slide 47-

General anesthetics have no effect on gastric pH. It is the method of choice in patients with a bleeding diathesis since regional anesthesia is contra-indicated. Although of concern to Anesthesiologists general anesthesia is not a major cause of maternal mortality. Succinylcholine is unable to cross the placenta and effect the fetus.
Slide 48-

MCQ 3. The following are all true concerning the nerve supply of the uterus , EXCEPT: A. Sensation from the upper segment travels with the sympathetic nerves to T11-T12 B. Sensation from the birth canal is via the pudendal nerve C. Lower segment innervation is via S2-4 D. Motor function occurs via sympathetic and parasympathetic nerves E. An intact nerve supply is essential to initiate normal labor
Slide 49-

MCQ 3. The following are all true concerning the nerve supply of the uterus , EXCEPT: A. Sensation from the upper segment travels with the sympathetic nerves to T11-T12 B. Sensation from the birth canal is via the pudendal nerve C. Lower segment innervation is via S2-4 D. Motor function occurs via sympathetic and parasympathetic nerves E. An intact nerve supply is essential to initiate normal labor
Slide 50-

Normal labor occurs in patients with a transected spinal cord.
Slide 51-

MCQ 4: Physiological changes seen in the last trimester include all EXCEPT A. Resting PaCO2 is decreased B. Hematocrit is decreased C. Blood volume is increased D. Gastric secretion is increased E. Total peripheral resistance is decreased
Slide 52-

MCQ 4: Physiological changes seen in the last trimester include all EXCEPT A. Resting PaCO2 is decreased B. Hematocrit is decreased C. Blood volume is increased D. Gastric secretion is increased E. Total peripheral resistance is decreased
Slide 53-

Gastric acid production does not increase. There is an increased risk of aspiration due to delayed gastric emptying and a decrease in lower esophageal sphincter tone.
Slide 54-

MCQ 5: All of the following are suitable for aspiration prophylaxis prior to caesarean section, EXCEPT: A. Metoclopramide B. Glycopyrollate C. Sodium citrate D. Clear fluids 4 hours pre-op E. Ranitidine
Slide 55-

MCQ 5: All of the following are suitable for aspiration prophylaxis prior to caesarean section, EXCEPT: A. Metoclopramide B. Glycopyrollate C. Sodium citrate D. Clear fluids 4 hours pre-op E. Ranitidine
Slide 56-

Metoclopramide acts as a pro-kinetic to empty the stomach of any gastric contents. Sodium citrate is a non-particulate antacid used to neutralize gastric contents. Ranitidine is an H2 antagonist used to prevent gastric acid secretion. Allowing clear fluids up to 4 hours prior to suregry has been shown to decrease the gastric content volume so decreasing the risk of aspiration. Glycopyrollate is an anti-sialogogue used for preoperative preparation when an awake intubation is anticipated.
Slide 57-

MCQ 6: All are suitable techniques for pain relief in labor EXCEPT: A. Transcutaneous electrical nerve stimulation B. White noise C. Epidural bupivacaine D. Intrathecal narcotics E. 70% Nitrous oxide in Oxygen
Slide 58-

MCQ 6: All are suitable techniques for pain relief in labor EXCEPT: A. Transcutaneous electrical nerve stimulation B. White noise C. Epidural bupivacaine D. Intrathecal narcotics E. 70% Nitrous oxide in Oxygen
Slide 59-

The concentration of nitrous oxide in oxygen when used for analgesia is 50%. Higher concentrations can result in loss of consciousness.
Slide 60-

MCQ 7: Which of the following is a contraindication to epidural analgesia in labor: A. Previous caesarean section B. Fetal distress C. INR 1.6 D. Maternal exhaustion E. Maternal multiple sclerosis
Slide 61-

MCQ 7: Which of the following is a contraindication to epidural analgesia in labor: A. Previous caesarean section B. Fetal distress C. INR 1.6 D. Maternal exhaustion E. Maternal multiple sclerosis
Slide 62-

Epidural analgesia is not contraindicated in patients who have had a prior C/S. The pain caused as a result of uterine rupture is not effectively masked by epidural analgesia. Fetal distress can be reduced by epidural analgesia so long as hypotension is avoided Maternal exhaustion is an indication for epidural analgesia. Maternal multiple sclerosis is not a contraindication to epidural analgesia as long as the concentration of local anesthetic is reduced Coagulopathy is an absolute contraindication to epidural analgesia
Slide 63-

MCQ 8 : Likely complications of epidural opioids include all of the following, EXCEPT: A. Itching B. Urinary retention C. Hypotension D. Respiratory depression E. Nausea
Slide 64-

MCQ 8 : Likely complications of epidural opioids include all of the following, EXCEPT: A. Itching B. Urinary retention C. Hypotension D. Respiratory depression E. Nausea