Record-breaking blood pH - survival following extreme acidosis

Normal cellular metabolism and function require that blood pH be maintained within narrow limits, 7.35-7.45. Even mild excursion outside this range has deleterious effect, and pH of less than 6.8 or greater than 7.8 is considered – according to medical and physiology texts – incompatible with life. Such a view is challenged by the detail of a recently published case report, which describes survival of a patient whose pH was just 6.53. 

The case concerns a 65-year-old man who suddenly became unwell at home and was brought to his local hospital emergency department in a state of shock with cool peripheries and marked hypotension (BP 80/40 mmHg). At this time blood gas results were within normal limits, despite increased lactate (5.4 mmol/L). 

After 2-hour fluid resuscitation, his condition deteriorated rapidly with onset of severe abdominal pain, persisting hemodynamic instability, agitation and eventually, cardiac arrest. Following restoration of cardiac activity, the patient was sent for emergency laparotomy because internal bleeding (possible ruptured aortic aneurysm) and resulting hypovolemia seemed a likely cause of the hemodynamic instability. 

Blood gas analysis immediately prior to surgery revealed profound metabolic acidosis (pH 6.527; Base Excess (BE) –34.2 mmol/L and lactate 15.6 mmol/L). At laparotomy, marked bleeding from a splenic artery was discovered; the artery was ligated and the spleen removed. By the end of surgery, acidosis had reduced somewhat (pH 6.989; BE –24.1 and lactate 11.5 mmol/L). 

During surgery and surgical recovery, the patient required 10 units of packed red cells and 8 units of fresh frozen plasma to replace the massive blood loss. After a not uneventful recovery period the patient was eventually discharged from hospital in good health. At a follow-up outpatient appointment, a full recovery with no long-term consequences was confirmed. 

In discussion of the case history, the authors cite two other cases from the literature in which patients made a full recovery following extreme acidosis. The first was a case of near drowning in which pH was 6.33, and the second was a case of metformin-induced lactic acidosis in which the pH was 6.481. They believe that the case they describe is the first to report recovery after a pH of 6.5 due to hypovolemic shock – and claim a world record!