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Analgesia During Pregnancy - Coggle Diagram
Analgesia During Pregnancy
Pain Pathways
First Stage
Afferents from cervix and lower uterine segment (T10-L1), visceral from spinal cord in dorsal horm
Contralateral Ventral Spinothalmic Tract -> Thalmic Activation -> Somatosensory cortex -> Prefrontal cortex -> Motor cortex -> Insular Cortex
Second Stage
Afferents from vagina and perineum via pudendal nerve S2-S4, Somatic pain, reflects distension ishcemia and direct injury
Maternal Systemic Effects of Labor Pain
CVS
Pain-induced increases in SNS activity, increase maternal cardiac output and peripheral vascular resistance, decrease uteroplacental perfusion
Respiratory
Intermittent hyperventilation with compensatory periods of hypoventilation between contractions resulting in episode of maternal hypoexmia
Childbirth of Preparation
Goals
Education about pregnancy, labour and delivery
Relaxation, breathing, participation of support, early parental bonding
Benefits
Greater maternal control and cooperation, decreased maternal anxiety,pain, need for analgesia, Stengthened family relationships
Labour Analgesia
Nonpharmacologic Analgesia
Minimal Training
Continuous support, touch/massage, therapeutic heat/cold, hydrotherapy, vertical position, aromatherapy
Focus on Sensory Component: Decreased maternal anxiety, analgesia requirement, less dissatisfaction
Touch and Massage: provides sense of comfort and caring
Heat/Cold: Widespread with no risk
Hydrotherapy: RCT results inconsistent
Vertical Position: Systematic reviews - Less pain in vertical group
Specialized Training
Biofeedback, Intradermal water injections, TENS, Acupuncture, Hypnosis
Biofeedback: Relaxation method using skin conductance/electromyographic relaxation
Intradermal Water injections: Treat lower back pain during labor
TENS: Low voltage electrical current via skin electrodes, easy to use and discontinue
Acupuncture: Requires trained personnel
Hypnosis: Mixed reports from studies
Pharmacologic
Systemic
Parenteral Agents
PCA opioid
Indications
Alternative to epidural, intrauterine fetal demise/termination of pregnancy
Advantages
Superior pain relief, less respiratory depression, less placental transfer, Less need for antiemetics, higher satisfaction
Disadvantages
Specialized equipment, Opioid side effects, small doses of opioids, risks of fetus and neonate unclear
Remifentanil
Short acting opioids
Favorable pharmacokinetic profile, rapidly metabolized into active metabolites
Higher maternal satisfaction compared with bolus opioid
Requires SpO2 monitoring with one-on-one nurisng
Acceptable safety profiles
Intermittent bolus parenteral opioid
Advantages: Simple, no specialized equipment or personnel, quick onset
Disadvantages
Materal Side Effects: Nausea, dysphoria, respiratory depression, drowsiness, delayed gastric emptying
Fetal: Decreased FHR variability, respiratory depression
Indications: Early Labor, no peidural, very late stage labor
Inhalation agents
Nitrous Oxide
Entonox
Intermittent inhlation via mask
Requires maternal cooperation
No effect on uterine activity
Negligible neonatal Effect
Environmental Pollution
Advantages
Ease of use
No requirement for physician supervision
Minmal Acumulation with intermittent use
Self administration provides control
Disadvantages
Does not provide complete analgesia
Drowsiness, disorientation, nausea
Regional Analgesia
Neuraxial Analgesia
Epidural Analgesia
Most effective analgesia
Highest patient satisfaction
Can provide complete anesthesia for 1st stage of patients, and modified analgesia for stage 2
Allows the conversion to epidural anesthesia if C/S is necessary
Epidural Space
L2-5
Midline Approach
3.5-10 cm deep
Blind, loss of resistance
Fine catheter left in-situ
Infuse LA +/- opioid
Contraindications
Patient refusal
Raised ICP
Infection at site of injection
Systemic infection
Coagulopathy
Uncorrected maternal hypovolemia
Active Neurological/disorder
Early Complications
failure, Hypotension, Dural puncture, high block/total spine, Intravascular injection, Motor block, Urinary retention
Late Complications
PDPH, Nerve injury, Epidural Abscess, CNs infection, Epidural Haematoma
Effects
Duration of Labour
Modest prolongation of second stage of labour -> Not clinically significant
C-Section Rate
Does not increase risk
Long term backache
Back pain is common after child birth
Epidural analgesia is not associated with increased incidence
Spinal Analgesia/ CSE Analgesia
Used in combination with epidural technique
Indications
Early labor, late first stage or rapid progress of labor
Advantages
Rapid onset, rapid and good sacral analgesia, complete analgesia with opioid alone
Disadvantages
Delayed verification of functioning epidural catheter, requires dural puncture, higher incidence of pruritus, higher risk of fetal bradycardia, limited analgesia duration
Regional Blocks
Paracervical
First stage of labour, rarely used due to risk of fetal bradycardia
Pudendal
S2-4, spontaenous vaginal delivery, frequent failure, inadequate for mid-forcepts delivery, repiar of upper vagina, cervic, and manual exploration of cavity
Perineal Infiltration
Most common Local technique for vaginal delivery, incomplete analgesia, rapid onset