We report the case of a 63-year-old man who suffered a witnessed pulseless electrical activity cardiac arrest on presentation to the emergency department. Despite a profound post-arrest acidosis (pH 6.48) he went on to make an unexpectedly good recovery. He was treated for metformin-associated lactic acidosis (MALA) and septic shock, although the origin of the sepsis was never confirmed. We discuss the growing evidence against the existence of MALA as a lone diagnosis and the aetiology of post-cardiac arrest metabolic acidosis.
AhmadSBeckettM. Recovery from pH 6.38: lactic acidosis complicated by hypothermia. Emerg Med J2002;19: 169–71.
4.
SaenzAFernandez-EstebanIMataixAMetformin monotherapy for type 2 diabetes mellitus. Cochrane Database of Systematic Reviews2005 Issue 3. Art no: CD002966. DOI 10.1002/14651858.CD002966.pub3.
5.
SalpeterSGreyberEPasternakGRisk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus. Cochrane Database of Systematic Reviews2006 Issue1. Art no: CD002967. DOI 10.1002/14651858. CD002967.pub2.
6.
WalkerRSLintonAL. Phenethyldiguanide: a dangerous side effect. BMJ1959;2 (5158): 1005–06.
7.
HolsteinANahrwoldDHinzeSContra-indications to metformin therapy are largely disregarded. Diabetic Med1999;16: 692–96.
8.
SulkinTVBosmanDKrentzAJ. Contraindications to metformin therapy in patients with NIDDM. Diabetes Care1997;20: 925–28.
9.
GaleaMJelacinNBramhamKSevere lactic acidosis and rhabdomyolysis following metformin and ramipril overdose. Br J Anaesth2007;98: 213–15.
10.
SchurePJde GooijerAvan ZantenAR. Unexpected survival from severe metformin-associated lactic acidosis. Neth J Med2003;61: 331–33.
11.
PetersNJayNBarraudDMetformin-associated lactic acidosis in an intensive care unit. Crit Care2008;12: R149.
12.
AguilarCRezaAGarciaJEBiguanide associated lactic acidosis: incidence and risk factors. Arch Med Res1992;23: 19–24.
13.
SitoriCRPassikC. Re-evaluation of a biguanide, metformin: mechanism of action and tolerability. Pharmacol Res1994;30: 187–228.
14.
BernardSAGrayTWBuistMDTreatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia. New Engl J Med2002;346: 557–63.
15.
OpdahlH. Survival put to the acid test: extreme arterial blood acidosis (pH 6.33) after near drowning. Crit Care Med1997;25: 1431–36.
16.
MakinoJUchinoSMorimatsuHA quantitative analysis of the acidosis of cardiac arrest: a prospective observational study. Crit Care2009;9: R357–62.
17.
LeavyJAWeilMHRackowEC. ‘Lactate washout’ following circulatory arrest. JAMA1988;260: 662–64.
18.
CardenDLMartinGBNowakRMLactic acidosis as a predictor of downtime during cardiopulmonary arrest in dogs. Am J Emerg Med1985;3: 120–24.
19.
DonninoMMillerNGoyalMEffective lactate clearance is associated with improved outcome in post cardiac arrest patients. Resuscitation2007;75: 229–34.
20.
MullnerMSterzFDomanovitsHThe association between blood lactate concentrations on admission, duration of cardiac arrest and functional neurological recovery in patients resuscitated from ventricular fibrillation. Intensive Care Med1997;23: 1138–43.
