Knowledge

• Latest
• Popular
• Reference
• Search…

• ---

  Decision support tools in anesthesia

  Cognitive aids Decision making

   
  • Review

    The Use of Cognitive Aids During Emergencies in Anesthesia: A Review of the Literature.

    Anesth. Analg.. 2013 Nov 1;117(5):1162-71.

  • Randomized Controlled Trial

    Adherence to guidelines for the management of local anesthetic systemic toxicity is improved by an electronic decision support tool and designated "reader".

    Reg Anesth Pain Med. 2014 Jul 1; 39 (4): 299-305.

  • Article

    Generation of dynamically configured check lists for intra-operative problems using a set of covering algorithms.

    Proc AMIA Symp. 2001 Jan 1:593-7.

  expand and show 7 more articles

• ---

  The wonderful world of perioperative magnesium

  Magnesium

   
  • Review

    Perioperative systemic magnesium to minimize postoperative pain: a meta-analysis of randomized controlled trials.

    Anesthesiology. 2013 Jul 1;119(1):178-90.

    Peri-operative systemic magnesium reduces postoperative pain and opioid consumption, although it is of uncertain clinical significance.

    pearl

  • Randomized Controlled Trial

    Do women with pre-eclampsia, and their babies, benefit from magnesium sulphate? The Magpie Trial: a randomised placebo-controlled trial.

    Lancet. 2002 Jun 1;359(9321):1877-90.

    Magnesium sulphate halves the risk of eclampsia in pre-eclamptic pregnant women without significant adverse effect.

    pearl

  • Randomized Controlled Trial

    The effect of magnesium sulphate infusion on the incidence and severity of emergence agitation in children undergoing adenotonsillectomy using sevoflurane anaesthesia.

    Anaesthesia. 2013 Oct 1;68(10):1045-52.

  expand collection

• ---

  Professionalism in anesthesia and medicine

  Anesthesia Decision making Professionalism

   
  • Review

    Physician professional behaviour affects outcomes: a framework for teaching professionalism during anesthesia residency.

    Can J Anaesth. 2011 Nov 1;58(11):1039-50.

  • Article

    Priorities for professionalism: what do surgeons think?

    Med. J. Aust.. 2015 May 4;202(8):433-7.

  • Article

    The role of maintenance of certification programs in governance and professionalism.

    JAMA. 2015 May 12;313(18):1809-10.

  expand and show 3 more articles

• ---

  Hyperalgaesia

  Pain

   
  • Review

    Review of the Performance of Quatitative Sensory Testing Methods to Detect Hyperalgesia in Chronic Pain Patients on Long-term Opioids.

    Anesthesiology. 2015 Mar 1;122(3):677-85.

  • Randomized Controlled Trial

    Preoperative pregabalin administration significantly reduces postoperative opioid consumption and mechanical hyperalgesia after transperitoneal nephrectomy.

    Br J Anaesth. 2012 May 1;108(5):845-9.

  • Article

    Opioid-Induced Hyperalgesia in Community-Dwelling Adults with Chronic Pain.

    Pain. 2015 Jun 1; 156 (6): 1145-1152.

  expand and show 8 more articles

• ---

  Morphine

  Drugs Morphine Opioid

   

  Morphine is one of the most commonly used opioids worldwide. First isolated in 1803 and commercially marketed by Merck in 1827.

  A. Physiochemistry

  • Natural phenathrene opioid - plant, animal and even human synthesis identified.
    • Synthesized by mammalian cells from dopamine, although exact role unclear.
  • pKa - 7.9 (20% nonionised @ 7.4)
  • Octanol water coefficient - 1.4 (relatively low lipid solubility compared with other opioids)
  • 3 rings attached to piperidine ring with a tertiary amine.

  B. Pharmacokinetics

  1. Dose - 50 mcg/kg IV
     • analgesia @ [plasma] 0.05 mcg/mL
     • epidural: 10-20 mcg/mL
     • PCA adult: 50 mg in 50 mL; 1 mL (1 mg) bolus 5 min lockout, commonly used.
     • PCA paeds: 1 mg/kg in 50 mL; 1 mL (20 mcg/kg) bolus; background 0.5-1 mL/h (10-20 mcg/kg/h).
  2. Absorption - IV, IM, s/c, po (3x dose as HER 0.69)
  3. Distribution - Vdcc 0.3, Vdss 3.5 L/kg
  4. Protein binding - 30% (albumin)
  5. Onset: peak onset at 20 min when given parenteral, 60 min orally; Offset 4 h
  6. Metabolism - t½α 10-20 min, t½ß 2-4 h
     • 75% metabolised by conjugation → 90% morphine-3-glucuronide (no activity)
     • 10% morphine-6-gluc (13x potency of morphine). MAOIs inhibit glucuronidation.
  7. Clearance - 15 mL/kg/min

  C. Pharmacodynamics

  1. Mech - mu, kappa, delta agonist. (GI linked). Effective against visceral, skeletal & joint pain.
  2. CNS - little CNS penetration (cf. heroin, which readily crosses BBB), although alkalisation (⇣pCO2) ⇡ non-ionised fraction, and ⇡pCO2 ⇡CBF. Both ⇡ cerebral morphine concentration.
     • 'Ceiling effect' on EEG reaching high voltage, slow frequency (delta 2-4 Hz) waves.
     • ⇣ CMRO2 & ⇣ ICP.
     • ⇡ cortical stimulation of Edinger-Westphal nucleus → miosis.
  3. CVS - ⇣ SNS & ⇡ PNS tone. Bradycardia, venodilation, histamine release (causes ⇣ MAP). Orthostatic hypotension due to depression of SNS responses. Direct depressant effect on SA node, slowing conduction (⇡ VF risk).
     • Administration with N₂O results in CVS depression.
  4. Resp - Respiratory depression & response to CO₂ & hypoxia (shift pCO₂/VA curve to right).
     • Bronchoconstriction due to histamine release (similar with pethidine). Depresses airway reflexes & ciliary reflexes.
  5. Renal - diuresis (kappa receptors → ADH release)
  6. GIT - Nausea & vomiting due to stimulation of CTZ (30-40% of subjets); ileus; constipation; sphincter of Oddi spasm.
  7. Pruritus

  reference

  ---

  • Review

    Morphine metabolites.

    Acta Anaesthesiol Scand. 1997 Jan 1; 41 (1 Pt 2): 116-22.

  • Review

    Endogenous morphine and its metabolites in mammals: history, synthesis, localization and perspectives.

    Neuroscience. 2013 Mar 13;233:95-117.

  • Review

    Morphine pharmacokinetics and analgesia after oral administration.

    Postgrad Med J. 1991 Jan 1; 67 Suppl 2: S60-3.

  expand and show 1 more article