The effects of sodium bicarbonate and a mixture of sodium bicarbonate and carbonate (“Carbicarb”) on skeletal muscle pH and hemodynamic status in rats with hypovolemic shock

Haemodynamic and metabolic effects in diabetic ketoacidosis in rats of treatment with sodium bicarbonate or a mixture of sodium bicarbonate and sodium carbonate

“…Instead of the deterioration in MABP seen in the latter series, there was a transient elevation in all treatment groups, with no significant difference between them. A similar pattern of response was observed in our previous study of skeletal muscle pH i in hypovolaemic shock [20]. Nor was significant elevation of blood lactate observed over the initial high values.…”

“…However, in a model of severe diabetic ketoacidosis identical to the present one except that it was not necessary to use artificial ventilation, we found no rise in lactate on bicarbonate infusion [28]. Nor in the study of skeletal muscle pH i in hypovolaemic shock referred to above [20], in which the protocol was similar to that in the present studies, except that thoracotomy and artificial ventilation were not employed, was any elevation of blood lactate observed on infusion of either bicarbonate or 'Carbicarb'. It therefore appears likely that the effect on blood lactate in the present study requires a background of artificial ventilation.…”

“…Furthermore, in the isolated rat liver perfused at acidotic pH, hepatic pH i rises on infusion of bicarbonate, despite a substantial elevation of portal vein PCO 2 [28]. There are clearly determinants of pH i other than PaCO2 [20] and we regard the argument concerning paradoxical intracellular acidification during bicarbonate therapy as of doubtful importance [29]. The risk of such acidification could in any case be eliminated in most clinical situations by slower infusion of bicarbonate than is often customary, thereby allowing respiratory elimination of CO 2 released by titration of bicarbonate [30].…”

“…Rats were anaesthetized, sternotomy performed and artificial ventilation instituted as for the DKA model. They were then rendered hypovolaemic by successive withdrawal of blood from the jugular vein over about 30 min in a manner previously described [20], until the mean arterial blood pressure, recorded with a Statham strain gauge reached 40mmHg. A 60-120rain period was allowed to elapse until pH~ was in the range 7.2-7.3.…”

Haemodynamic and metabolic effects in diabetic ketoacidosis in rats of treatment with sodium bicarbonate or a mixture of sodium bicarbonate and sodium carbonate

“…Yet, in both alkali-treated groups there was an elevation of the time-averaged myocardial pH i . However, in our studies [20] of skeletal muscle pHi response to sodium bicarbonate and 'Carbicarb' in haemorrhagic shock, a similar differential in the course of PaCO2 was also not reflected in pHi, which in that study could be measured at 60-s intervals, because of the availability of the carbon-2 proton resonance of anserine for pHi determination by the more sensitive proton MRS. Furthermore, in the isolated rat liver perfused at acidotic pH, hepatic pH i rises on infusion of bicarbonate, despite a substantial elevation of portal vein PCO 2 [28].…”