Sign in

Review Note

Last Update: 03/27/2025 10:44 PM

Current Deck: ACG Part 2::Obstetrics

New Card (Unpublished)

Currently Published Content

Front
Back

No published tags.

Pending Suggestions

Field Change Suggestions:
SS_OB 1.36 Discuss the pathophysiology and anaesthetic management of co-existing maternal conditions as described in the Perioperative medicine Clinical Fundamental, in particular:
- Substance abuse 
Drug Abuse and Obstetric Complications
  • Drug abuse is a significant social problem that can lead to serious obstetric complications.
  • The effects of drug abuse can mimic diseases such as pre-eclampsia.
  • Drug users have more health problems and pregnancy complications.
    • 80% of substance-abusing patients require anaesthetic services in the perinatal period.
    • Drug abuse poses a number of challenges – management of pain and anaesthesia in the peripartum period.
    • Anaesthetists should be aware of the potential risks associated with the abuse of illicit substances.
  • Measuring the impact of drug exposure on the fetus has proven difficult. Only animal studies provide information on the toxic or teratogenic effects of some drugs.
    • Fetal complications: Developmental disabilities, low birth weight, prematurity.
Anaesthetic Management
  • Early antenatal review is recommended.
  • Careful evaluation with non-judgemental questioning is essential.
  • Management should be tailored to individual patient needs and the urgency of obstetric intervention (for vaginal delivery or LSCS).
  • Opioid-dependent women and those recovering from drug addiction benefit from antenatal pain management planning.
Marijuana & Anaesthesia
  • Acute toxicity or major anaesthesia interactions are rare.
  • Abstinence following exposure to 4-5 cigarettes/day has been associated with withdrawal syndrome:
    • Increased latency to fall asleep, negative mood, and behavioural symptoms.
  • Every system is affected by marijuana use, and its clinical picture is unpredictable.
Effects on:
  • ANS / CVS
    • Low to moderate doses: Increased SNS activity, reduced PNS activity, leading to tachycardia and increased CO.
    • High doses: Inhibition of SNS, but not PNS activity, leading to hypotension and bradycardia.
    • Increased supraventricular or ventricular ectopic activity, reversible ST-segment and T-wave abnormalities.
    • Increased myocardial depression and tachycardia.
      • Anaesthesia can compound myocardial depression, affecting anaesthesia induction.
      • Drugs increasing HR (e.g., ketamine, pancuronium, atropine, adrenaline) should be avoided.
  • CNS
    • Marijuana in combination with other sedative-hypnotic drugs may enhance CNS depression.
  • Respiratory
    • Upper airway irritability, impairment of airway epithelial function, damage to bronchial tissue, chronic cough, bronchitis, emphysema, and bronchospasm.
    • Reports of oropharyngitis, acute upper airway oedema, and obstruction in cannabis-smoking patients undergoing GA.
  • Utero-placental
    • Chronic use of marijuana may reduce uteroplacental perfusion, resulting in IUGR and low birth weight.
    • Increased risk of complications during labour.
    • Delayed cognitive development in infants.
Cocaine & Anaesthesia
  • Regional Anaesthesia
    • Cocaine-induced thrombocytopaenia can occur, potentially precluding use of RA.
    • Patients under RA may show combative behaviour and altered pain perception (due to changes in opioid receptor densities and abnormal endorphin levels).
  • CVS Effects
    • Ephedrine-resistant hypotension may be encountered; low-dose phenylephrine usually restores BP.
    • Severe hypertension may occur due to direct laryngoscopy in cocaine-intoxicated patients undergoing GA.
      • Managed with antihypertensives (labetalol, GTN, CCB).
      • Beta-blockers are contraindicated due to potential unopposed alpha-adrenergic stimulation and potential for enhanced cocaine-induced coronary vasoconstriction.
    • Volatile anaesthetics may produce cardiac arrhythmias and increased SVR in acutely intoxicated cocaine patients.
    • Ketamine should be used with caution or avoided.
    • Propofol and thiopental have been proven to be safe.
  • Cocaine & Pregnancy
    • Pregnancy enhances the CVS toxicity of cocaine, worsening its complications due to increased oxygen demand and decreased supply (increased HR, BP, and LV contractility).
    • Rapid transplacental diffusion and high fetal-blood and tissue cocaine levels lead to:
      • Fetal distress, placental abruption, preterm delivery, fetal tachycardia, HTN, FDIU.
      • Decreased uteroplacental blood flow, resulting in insufficiency, acidosis, hypoxia, and distress.
    • 4x increase in emergency LSCS.
Opioids & Anaesthesia
  • Methadone may be a suitable opioid substitute, preventing withdrawal symptoms and reducing cravings for more drugs.
  • Buprenorphine is considered a safer alternative than methadone. Is generally considered safe in pregnancy especially compared to illicit opioid use or untreated opioid dependence 
    - lower risk of severe neonatal abstinence syndrome compared to methadone 
    - improved materal health outcomes and reduced risks of preterm birth, low birth weight and fetal distress compared to continued drug use 
  • Antagonists or agonist-antagonists administered via any route must be avoided in addicts as they can precipitate acute withdrawal syndrome.
    • Clonidine can be used to treat withdrawal, replacing opioid-mediated inhibition with alpha2-agonist-mediated inhibition of the CNS.
    • Opioid administration will also reverse withdrawal.
  • RA can be administered safely to opioid-dependent patients.
  • Patients may have difficult peripheral and central venous access.
  • May have concomitant liver disease, malnutrition, and reduced IV fluid volume, which may require adjustments in anaesthetic drug doses.
  • Acute administration of opioids decreases MAC or anaesthetic requirements.
  • Chronic opioid abuse leads to cross-tolerance of anaesthetic drugs and other depressants.
  • Post-op analgesia will be challenging.
Opioids & Pregnancy
  • Transplacental opioid transfer leads to fetal IUGR, fetal distress, and neonatal opioid withdrawal.
  • Methadone poses fewer hazards to the mother and fetus.
Hallucinogens & Anaesthesia
  • Risk of autonomic dysregulation is high:
    • Wide swings in BP and tachycardia should be prevented due to an increased risk of cardiomyopathy, coronary, and cerebral vasospasm.
    • Extreme caution should be used with ephedrine, due to hallucinogens' sympathomimetic stimulation effects.
    • Hallucinogen users exhibit an exaggerated response to sympathomimetic drugs, with arrhythmias likely.
  • May prolong the analgesic and ventilatory depressant effects of opioids.
  • Close evaluation of fluids and electrolytes is essential:
    • Ecstasy users may overzealously consume water, leading to water intoxication, cerebral oedema, and pulmonary oedema.
  • Avoid volatile agents and succinylcholine in patients with a history of MDMA-related hyperthermia.
  • Anaesthetic drugs metabolized through the liver and eliminated through the kidneys may have a prolonged effect due to fatty liver changes and acute renal failure.
Hallucinogens & Pregnancy
  • Misdiagnosis of pregnancy-related diseases:
    • Amphetamine-like medications may cause symptoms (hypertension, proteinuria, seizures) to be misdiagnosed as pre-eclampsia or eclampsia.
  • Higher risk of premature labour and delivery.
  • Fetal IUGR, meconium-stained fluid, and neonatal withdrawal syndrome.
  • Hyperthermia induced by these drugs increases maternal and fetal oxygen consumption.
  • Congenital defects if MDMA is taken during pregnancy:
    • Cardiac anomalies, cleft lip & palate, biliary atresia, fetal IUGR, FDIU, cerebral haemorrhage.

Terms of Service | Privacy Policy | Imprint (German)

Copyright © AnkiCollab. Website Template Designed & Developed by Quixlab 2018