Analgesiaanesthesia Pudendal block local anesthetic is inltrated into

Analgesia/anesthesia • Pudendal block • -local anesthetic is infiltrated into the tissue around the pudendal nerve within the pelvis • -The pudendal nerve emerges from the spine at the level of the S 2–S 4 vertebrae and ‘descends’ into the pelvis crossing behind the ischial spine.

• • - The pudendal nerve supplies: the levator ani muscles the deep and superficial perineal muscles the sensory nerves (pain/stretch and temperature) of the lower vagina and perineum.

• -A pudendal needle with 20 ml of local anaesthetic, usually 1% lidocaine (lignocaine), being injected into the region around and below the ischial spine. • both motor and sensory nerves are a�ected with this technique it may be used to provide analgesia for the lower vagina and perineum, and is therefore used during forceps and ventouse instrumental births.

Perineal infiltration • infiltration and repair of episiotomy, as well as third- and fourth- degree perineal trauma. • Regional anaesthesia • -epidural and intrathecal (spinal) anaesthetic. • -The epidural space is the space located within the bony spinal canal just outside the dura mater. • - In contact with the inner surface of the dura is another membrane called the arachnoid mater.

• -The cerebrospinal fluid (CSF) is contained between the arachnoid mater and the pia mater, another membrane that lies directly in contact with the spinal cord. • -In adults, the spinal cord terminates at the level of the lower border of the L 2 vertebra below which lies a bundle of nerves known as the cauda equina (‘horse’s tail’).

• Insertion of an epidural needle involves threading a needle between the spinal vertebrae, through the ligaments and into the epidural potential space taking great care not to puncture the dura mater immediately below, which contains the CSF.

• Techniques • -the operator to be technically proficient in order to avoid complications. • -placed in the seated or lateral positions. • - Intravenous access. • aseptic technique protocol, the level of the spine at which the catheter/spinal needle is to be placed is identified

Epidural • -The iliac crest anatomical landmark for lumbar epidural injections, as this level roughly corresponds with the fourth lumbar vertebra, which is usually below the termination of the spinal cord. • - infiltration of local anaesthetic, • A syringe containing saline is attached to the needle

• -A catheter is then threaded through the needle (typically 3– 5 cm into the epidural space), • the needle withdrawn and the catheter secured to the skin with adhesive tape or dressings to prevent it becoming dislodged. -The catheter is a fine plastic tube, through which anaesthetic drugs may be injected into the epidural space. • -Many epidural catheters have three or more orifices to reduce the incidence of catheter blockage

• -A person receiving an epidural for pain relief may receive local anaesthetic (most commonly levo-bupivacaine), with or without an opioid (most commonly fentanyl). • These are injected in relatively small doses, compared to when they are injected intravenously or intramuscularly.

• For a prolonged e�ect, a continuous infusion of drugs may be employed. -The epidural catheter is usually removed prior to transfer to the postnatal ward.

Spinal anaesthesia • -Intrathecal (spinal) anaesthesia is a technique whereby a local anaesthetic drug is injected into the cerebrospinal fluid through a fine (24– 26 gauge) spinal needle. • spinal is differ from epidura anaesthesiainclude: • Intrathecal anaesthesia requires a lower dose of drug and has a faster onset than epidural anaesthesia.

• The block achieved with spinal anaesthesia is more • A spinal anaesthetic block typically lasts for 2 hours, however it cannot be topped up, as no catheter is inserted. • Intrathecal injections are performed below the second lumbar vertebral body to avoid damaging the spinal cord.

Complications • @Failure to achieve analgesia or • @only partial analgesia or anaesthesia. If analgesia is inadequate, another epidural may be attempted

factors are associated with failure to achieve epidural analgesia/anaesthesia: • Obesity • history of a previous failure of epidural anaesthesia • history of substance abuse (with opiates) • advanced labour (cervical dilatation of more than 7 cm at insertion) • previous history of spinal surgery.

• @Accidental dural puncture with headache • puncture the dura (and arachnoid) with the needle, causing cerebrospinal fluid (CSF) to leak out into the epidural space. Which lead to a post-dural puncture headache (PDPH). • headche is severe and last several days, and in some rare cases weeks or months.

• It is caused by a reduction in CSF pressure and is characterized by postural exacerbation when the subject raises his/her head above the lying position. • If severe it may be successfully treated with an epidural blood patch • most cases resolve spontaneously with time.

• Bloody tap • Injury an epidural vein with the needle. • people who have a coagulopathy may be at increased risk.

@Catheter misplaced into the subarachnoid space • Rare, If the catheter is accidentally misplaced into the subarachnoid space normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anesthetist to withdraw the catheter and re-site it

• not recognized, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. • result in a high block, a total spinal, anaesthetic is delivered directly to the brain stem, causing unconsciousness and sometimes seizures. • Neurological injury lasting less than 1 year

• @Death • @ Epidural haematoma formation • (Neurological injury lasting longer than 1 year • @Paraplegia

• General anaesthesia • -usually more rapidly administered than a regional block, • is important (when the fetus is in serious jeopardy).

• pre-oxygenated (they are given oxygen to breathe for several minutes) prior to the ‘rapid sequence’ induction of anaesthesia with the intravenous administration of anaesthetic (e. g. thiopentone or propofol) followed by a muscle relaxant (e. g. suxamethonium) and cricoid pressure is applied (essential to reduce the risks of aspiration of stomach contents).

• Maternal unconsciousness within seconds and oro -tracheal intubation is secured with a cu�ed tube. • -Anaesthesia is sustained by inhalational anaesthetic means (commonly enflurane or sevoflurane) with an opioid administered intravenously after clamping the cord.

Difficult or failed intubation • more likely to occur in pregnant women, who have pregnancy-induced hypertension or who are obese. • -Access to the larynx may be obstructed or di�cult to view.

• The management of a failed intubation is primarily to maintain adequate oxygenation via assisted ventilation of the woman until the e�ects of suxamethonium and thiopentone have worn o�and the woman has regained consciousness. • -continued application of cricoid pressure and ventilation via a face mask.

Complications of general anasthesia • Mendelson's syndrome • a chemical pneumonitis caused by the reflux of gastric contents into the maternal lungs during a general anaesthetic. • The acidic gastric contents damage the alveoli, impairing gaseous exchange. • impossible to oxygenate the woman and death may result.

The predisposing factors for mendlson syndrome • pressure from the gravid uterus • the e�ect of the progesterone relaxing smooth muscle and the cardiac sphincter of the stomach. • Analgesics administered during labour (e. g. pethidine) can cause significant delay in gastric emptying

Prevention of Mendelson's syndrome • @Antacid therapy. • all women in whom a caesarean is planned or anticipated. • women having an elective operation to be given two doses of oral ranitidine 150 mg approximately 8 hours apart.

• If a general anaesthetic is anticipated, 30 ml of sodium citrate should be orally administered immediately before induction. • @Cricoid pressure. • pressure is exerted on the cartilaginous ring below the larynx, the cricoid, to occlude the oesophagus and prevent reflux • To prevent pulmonary aspiration.

• -Cricoid pressure is administered during the induction of a general anaesthetic • is maintained until the tracheal tube is confirmed as being correctly positioned and the seal of the cuff inflated.

Clinical intervntions proven to reduce the rates o f birth by CS – – – External cephalic version (ECV) at 36 weeks Continuous support in labor Induction of labor for pregnancies beyond 41 weeks Use of a partogram with a 4 hour action line in labor Fetal blood sampling before caesarean section for abnormal cardiotocograph in labour – Support for women who choose vaginal birth after caesarean section