Analgesia & anesthesia in obstetrics Uterine contractions and cervical dilatation result in visceral pain (T10 to L1). As labor progresses, the descent of fetal head and subsequent pressure on the pelvic floor, vagina and perineum generate somatic pain transmitted by pudendal nerve (S2 to S4). An analgesic (also known as a painkiller) The word analgesic derives from Greek an- ("without") and algos ("pain"). An anesthetic is a drug that causes anesthesia—reversible loss of sensation. They contrast with analgesics (painkillers), which relieve pain without eliminating sensation.anesthesiaanalgesics

Types of analgesia and anesthesia in obstetrics 1-Non pharmacological methods -Relaxation and breathing exercise but prolonged hyperventilation causes dizziness and alkalosis - aqupuncture -Trans cutaneous electrical nerve stimulation (TENS); it blocks pain fibers in the posterior ganglia of the spinal cord (the gate theory) -Relaxation in warm water during first stage can lead to sense of well being

2-Pharmacological methods A-Opiates: 1-as Pethidine are still used in obstetrics It causes degree of sedation, nausea and vomiting, cause respiratory depression in the new born, naloxone counter act its effect Delayed gastric emptying in the mother which is dangerous if the patient needs general anesthesia because it causes regurgitation and pulmonary aspiration unless skilled cricoids pressure is applied So the use of ranitidine for women who may need GA or use pethidine 2--Diamorphine is better than pethidine but it cause greater respiratory depression in the newborn

Use: Intramuscular, subcutaneous or intravenous by patient controlled analgesia (PCA) according to patients needs she press a button 3--Other type of opiates is the remifentanil it can be timed with contractions B-Inhalational analgesia Nitrous oxide (an equal mixture of NO and oxygen) is used in most labor wards It has quick onset, short duration Adverse effects: light headedness, nausea It is not suitable for prolonged use because it leads to hyperventilation and fetal hypoxia It is suitable late in labor or while awaiting epidural analgesia

C-Regional analgesia: Partial to complete loss of pain sensation below the T8 to T10 level. A varying degree of motor blockade may be present, depending on the agents used. Spinal, epidural and combined spinal epidural are the most flexible, effective and lest depressing to the CNS.

1-Epidural analgesia (extradural) Most reliable and effective analgesia in labor Indications: Counseling is important the patient should be warned that she may have temporary loss of sensation and movement in her legs Effective pain relief Prolonged labor Maternal hypertension Multiple gestation If there is high risk of needing operative intervention Certain maternal medical diseases Contraindications Coagulation disorder Sepsis Hypovolaemia Lack of trained staff

Technique I V infusion of crystalloids (hartmanns or N/S) prior to insertion of cc preload to prevent hypotension, Catheter inserted at L2-L3 or L4- L5 interspacein the epidural space which contain blood vessles and nerve roots. Then small dose is shot into the catheter using drug bupivacaine if no effect on sensation in the lower limb the catheter is in correct space wait for 5 minutes and then complete the dose While if there is leg weakness and vasodilationso the catheter is in the suarachnoid space (spinal) if we give the normal dose it causes complete motor and respiratory pasralysis Keep the patient laterl position never supine,cheque blood pressure if hypotension occur give IV fluid and may need ephedrine (vasoconstrictor) The regional analgesia is maintained by intermittent or continuos infusion

2-Spinal analgesia Atraumatic spinal needle is introduced through the epidural, dura nd into the subarachnoid space which contain the CSF, small amount of local anesthetist injected and the needle withdrawn Uses: For c/s, instrumental delivery, manual removal of placenta suturing of tears It is not used for routine analgesia in labor

3-Combined spinal and epidural analgesia Rapid onset of pain relief and prolong anesthesia Complications of regional analgesia -Hypotension -1% accidental dural puncture leading to leakage of CSF leading to spinal headack exacerbated in sitting position and relieved wth lying flat -Accidental total spinal anesthesia causes severe hypotension and respiratory failure unconsciousness and death if not recognized Treatment by intubation, ventilation, circulatory support, iv fluid vasopressors and left uterine displacement and urgeant delivery of the fetus -neurological complications -drug toxicity -bladder dysfunction if over distention of bladder so catheterization is mandatory -backache -increase instrumental delivery with epidural analgesia

Laceration Drug used is lidocain 5-pudendal block Needle passed and its end just beneath the tip of the ischial spine Using lidocaine 1%

Induction with IV agents, rapid sequence intubation. Maintenance with N2O All inhaled anesthetic agents readily cross the placenta and have been associated with neonatal depression. Ideally, induction-to-delivery time should be minimized by 8 min. Halogenated agents are potent uterine relaxants in high concentration. Increase blood loss during C/S Maternal mortality:. Anesthesia-related maternal mortality accounts for more than 5% of maternal deaths. The increased safety of regional analgesia has increased the relative risk of GA Failed intubation occurs in 1/250 General anesthesia is indicated in some cases of fetal heart rate abnormality and urgent C/S (eg, severe intrauterine growth restriction)

6-paracervical block Gives good pain relief during first stage of labor Complication: fetal bradycardia

6-paracervical block Gives good pain relief during first stage of labor Complication: fetal bradycardia General anesthesia Induction with IV agents, rapid sequence intubation. Maintenance with N2O All inhaled anesthetic agents readily cross the placenta and have been associated with neonatal depression. Ideally, induction-to-delivery time should be minimized by 8 min. Halogenated agents are potent uterine relaxants in high concentration.

Increase blood loss during C/S Maternal mortality:. Anesthesia-related maternal mortality accounts for more than 5% of maternal deaths. The increased safety of regional analgesia has increased the relative risk of GA Failed intubation occurs in 1/250 General anesthesia is indicated in some cases of fetal heart rate abnormality and urgent C/S (eg, severe intrauterine growth restriction)