managing labour pains by anaesthesia.pptx

Anaesthesia

1. Management Of Labor Pain By Dr. Aliza Resident Anesthesiology SIHS

2. Etiology Of Pain During Labor Physical Pain: Contraction Of Myometrium Stretching Of Cervix and Perineum Emotional Factors Fear Of Unknown Anxiety Previous Unpleasant Experience

3. Nonpharmacological Analgesic Techniques Psychological Analgesic techniques (Bradley, Dick-Read, Lamaze and LeBoyer ) Hypnosis Transcutaneous Electrical Nerve Stimulation Biofeedback Acupuncture

4. Parenteral Agents Systemic Opioids In Labor Advantages: Easy Administration Inexpensive Avoids Complications Of Regional Blocks Does Not Require Highly Skilled Personnel

5. Systemic Opioids - Disadvantages Cross the Placenta Maternal Respiratory Depression and Sedation Nausea, Vomiting, Gastric Stasis Loss Of Beat-to-Beat Variability of FHR Neurobehavioral Depression of Neonate Low Apgar Scores Respiratory Acidosis

6. Opioids Meperidine: 10 to 25mg IV or 25 to 50mg IM Fentanyl: 25 to 100mcg/ hr Remifentanil PCA: 40mcg bolus with 2 minutes lockout Butorphanol: 1 to 2mg Nalbuphine: 10 to 20mg

7. NSAIDs Not recommended Suppress Uterine Contractions Promote Early Closure of Ductus Arteriosus Various Agents: Promethazine (25 to 50mg IM) Hydroxyzine (50-100mg IM) Midazolam (up to 2mg in combination) Ketamine (10 to 15mg IV)

8. Inhalational Analgesia: Entonox Easy to Administer Satisfactory Analgesia Minimal Neonatal Depression

9. Inhalational Analgesia: Isoflurane Enflurane Desflurane Limited use due to Drowsiness High Cost Unpleasant Smell Accidental Overdose

10. Regional Blocks Pudendal Nerve Block: Technique: A special needle ( koback ) is used and placed transvaginally underneath ischial spine on each side. The needle is advanced 1-1.5cm through sacrospinous ligament and 10ml of 1% lidocaine or 2% chloroprocaine is injected following negative needle aspiration. Complications: Intravascular Injection Retroperitoneal Hematoma Retropsoas Or Subgluteal Abscess

11. Paracervical Plexus Blocks No Longer Used Due To Possibility Of: Fetal Bradycardia Uterine Arterial Vasoconstriction Uteroplacental Insufficiency Local Anesthetic Insufficiency

12. Regional Techniques Epidural Analgesia Spinal Analgesia Combined Spinal and Epidural Analgesia Continuous Epidural Analgesia Continuous Spinal Analgesia

13. Choice Of Drugs Local anesthetics were administered to block both the visceral and somatic pain of labor Intrathecal opioids effectively relieve pain of first stage of labor although they should be combined with LA to relieve pain of first and second stages of labor Addition of opioid to LA shortens latency Contemporary epidural labor analgesia practice most often incorporates low doses of long acting local anesthetic combined with lipid soluble opioid

14. Local Anesthetics Bupivacaine Most commonly used for labor neuraxial analgesia Highly protein bound, limits trans-placental transfer Ropivacaine Levo bupivacaine Lidocaine 2-chlorprocaine

15. Opioids In clinical practice, epidural fentanyl and sufentanil are usually administered with a local anesthetic for initiation of analgesia Addition of opioid to LA for neuraxial labor analgesia decreases latency, prolongs the duration of analgesia, decreases epidural LA requirement, decreases motor blockade and improves quality of analgesia

16. Advantages Of Lower Dose Of Local Anesthetics: Decreased risk for local anesthetic systemic toxicity Decreased risk for high or total spinal anesthesia Decreased intensity of motor blockade

17. Epidural Test Dose Purpose is to help identify unintentional cannulation of a vein or subarachnoid space Epidural test dose: Placement of an epidural catheter and administration of a standard dose of lidocaine 45mg/ epinephrine 15mcg

18. Maintenance Of Analgesia Combination of a low dose, long-acting amide local anesthetic and a lipid soluble opioid This approach improves safety and leads to less motor blockade and greater patient satisfaction.

19. Administration Techniques 1. Intermittent Bolus Analgesia re-established with bolus injection of 8 to 12 ml of LA/Opioid solution. Pain relief is constantly interrupted by regression of analgesia The spread and quality of analgesia may change with the repeated lumbar epidural injections. 2. Continuous Infusion Prolonged infusion might lead to significant motor blockade. Therefore, dose requires titration. Strict monitoring is required as migration of catheter into subarachnoid, subdural or intravenous spaces are likely to go unnoticed.

20. Side effects of Neuraxial Analgesia Hypotension Pruritis Nausea and vomiting Fever Shivering Urinary retention Delayed Gastric Emptying

21. Complications of Neuraxial Analgesia Inadequate Analgesia Unintentional Dural puncture Respiratory Depression Intravascular Injections of LA Extensive Motor Blockade Prolonged Blockade Sensory change Back Pain Pelvic Floor injury

22. Inadequate Analgesia Successful Location of the epidural space is not always possible and satisfactory analgesia does not always occur, even when the epidural space has been identified correctly. Factors such as patient age and weight, the specific technique, the type of epidural catheter, and the skill of anesthesia provider are associated with the rate of failure of neuraxial analgesia. The risk for failed anesthesia and the potential need to place a second epidural catheter should be discussed with the patient during preanesthetic evaluation, before placement of the first epidural catheter. Three types mainly: Extent of block is inadequate. Asymmetric block Breakthrough pain

23. Unintentional Dural Puncture Rate of unintentional Dural puncture with an epidural needle or catheter was 1.5% Options: Remove the needle and place an epidural catheter at another interspace; If CSE analgesia was planned, the intrathecal dose may be injected through the epidural needle before it is removed and re-sited at a different interspace. The anesthesia provider may place a catheter in the subarachnoid space and administer continuous spinal analgesia for labor and delivery.

24. High and Total spinal Anaesthesia May occur after unintentional and unrecognized injection of local anesthetic (via a needle or catheter) into either the subarachnoid or subdural space. Alternatively, the epidural catheter may migrate into the subarachnoid or subdural space during the course of labor and deliver. High spinal blockade may result from overdose of local anesthetic in epidural space.

25. Contraindications Patient refusal or inability to cooperate. Increased intracranial pressure secondary to a mass lesion Skin or soft tissue infection at the site of needle placement Frank coagulopathy Uncorrected maternal hypovolemia (e.g. haemorrhage )

26. Benefits of Epidural Analgesia Epidural analgesia may facilitate an atraumatic vaginal breech delivery, the vaginal delivery of twin infants, and vaginal delivery of preterm infant. By providing effective pain relief, epidural analgesia facilitates the control of blood pressure in pre-eclamptic women. Epidural Analgesia also blunts the hemodynamic effects of uterine contractions and the associated pain response Prevents hypoventilation hyperventilation syndrome.

27. Administration of Epidural Analgesia for Labor: Technique Informed consent is obtained and obstetrician is consulted. Monitoring includes the following: Blood pressure every 1 to 2 minutes for 15 minutes after giving bolus of local anesthetic Continuous maternal heart rate monitoring during and after administration of the block. Continuous fetal heart rate monitoring during and after the procedure and continual verbal communication.

28. Administration of Epidural Analgesia for Labor: Technique The patient is hydrated with 500 ml. of Ringer’s lactate solution. The patient assumes a lateral decubitus or sitting position. The epidural space is identified with a loss-of-resistance technique. The epidural catheter is advanced 3 to 5 cm into the epidural space. A test dose of 3 mL of 1.5% lidocaine with 1:200,000 epinephrine is injected after careful aspiration and after a uterine contraction (to minimize the chance of confusing tachycardia that results from the pain with tachycardia as a result of intravenous injection of the test dose.)

29. Administration of Epidural Analgesia for Labor: Technique If the test done is negative, one or two 5-mL doses of 0.25% bupivacaine are injected to achieve a cephalad sensory level of approximately T10. After 15 to 20 minutes, the block is assessed by means of loss of sensation to cold or pinprick. The patient is cared for in the lateral or semi lateral position to avoid aortocaval compression. Subsequently, maternal blood pressure is measured every 5 to 15 minutes. The fetal heart rate is monitored continuously. The level of analgesia and the intensity of motor block are assessed every 1 to 2 hours.

30. Saddle Block Advantageous in the patient with a preterm fetus or vaginal breech presentation. In these cases, dense perineal relaxation may facilitate an atraumatic vaginal delivery. A saddle block also provides excellent anesthesia for an outlet/low forceps delivery. The block is administered with the patient in the sitting position to promote caudal spread of the hyperbaric local anesthetic. We administer the local anesthetic immediately after a uterine contraction to decrease the likelihood of an unexpected high block.

31. Continuous Spinal Analgesia Placed through 18- or 19-gauge needle. Very small (e.g. 28- to 32-gauge) catheters. Were developed for insertion through small (e.g. 22- to 26-gauge) spinal needles. Unfortunately, several cases of cauda equina syndrome (associated with the use of spinal micro catheters during surgery in non-pregnant patients) prompted the Food and Drug Administration to remove these micro catheters from the market.

32. Spinal Analgesia for Labor: Single Shot Technique A single-shot subarachnoid injection of local anesthetic is not suitable for the first stage labor. A single-shot injection has finite duration and multiple injections result in an increased risk of post dural puncture headache (PDPH).

33. Combined Spinal And Epidural Analgesia Benefits patients with severe pain early in labor Or for immediate analgesia prior to delivery Typical Intrathecal doses for CSE are Fentanyl: 10-12.5mcg Sufentanil : 5mcg Bupivacaine 2.5mg Rupivacaine 3-4mg

34. General Anesthesia Avoided due to risk of aspiration Used only in a true emergency during vaginal delivery Indications: Fetal distress during second stage Tetanic uterine contractions Breech extraction Version and extraction Manual removal of a retained Placenta Replacement of an inverted uterus