Cardio-cerebral and metabolic effects of methylene blue in hypertonic sodium lactate during experimental cardiopulmonary resuscitation.
BACKGROUND
Methylene blue (MB) administered with a hypertonic-hyperoncotic solution reduces the myocardial and cerebral damage due to ischaemia and reperfusion injury after experimental cardiac arrest and also increases short-term survival. As MB precipitates in hypertonic sodium chloride, an alternative mixture of methylene blue in hypertonic sodium lactate (MBL) was developed and investigated during and after cardiopulmonary resuscitation (CPR).


METHODS
Using an experimental pig model of cardiac arrest (12 min cardiac arrest and 8 min CPR) the cardio-cerebral and metabolic effects of MBL (n=10), MB in normal saline (MBS; n=10) or in hypertonic saline dextran (MBHSD; n=10) were compared. Haemodynamic variables and cerebral cortical blood flow (CCBF) were recorded. Biochemical markers of cerebral oxidative injury (8-iso-PGF2alpha), inflammation (15-keto-dihydro-PGF2alpha), and neuronal damage (protein S-100beta) were measured in blood from the sagittal sinus, whereas markers of myocardial injury, electrolytes, and lactate were measured in arterial plasma.


RESULTS
There were no differences between groups in survival, or in biochemical markers of cerebral injury. In contrast, the MBS group exhibited not only increased CKMB (P<0.001) and troponin I in comparison with MBHSD (P=0.019) and MBL (P=0.037), but also greater pulmonary capillary wedge pressure 120 min after return of spontaneous circulation (ROSC). Lactate administration had an alkalinizing effect started 120 min after ROSC.


CONCLUSIONS
Methylene blue in hypertonic sodium lactate may be used against reperfusion injury during experimental cardiac arrest, having similar effects as MB with hypertonic saline-dextran, but in addition better myocardial protection than MB with normal saline. The neuroprotective effects did not differ.
Miclescu
Adriana
A
Department of Surgical Sciences/Anaesthesiology, Faculty of Medicine, Uppsala University, S-751 85 Uppsala, Sweden. adriana.miclescu@akademiska.se
Basu
Samar
S
Wiklund
Lars
L
D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D002560:Cerebrovascular Circulation / Q000187:drug effects; D003326:Coronary Circulation / Q000187:drug effects; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects*; D006323:Heart Arrest / Q000378:metabolism* / Q000503:physiopathology / Q000628:therapy; D006982:Hypertonic Solutions / Q000008:administration & dosage; D008751:Methylene Blue / Q000008:administration & dosage / Q000494:pharmacology*; D009206:Myocardium / Q000378:metabolism; D019354:Sodium Lactate / Q000008:administration & dosage; D013552:Swine
D004791:Enzyme Inhibitors; D006982:Hypertonic Solutions; D008751:Methylene Blue; D019354:Sodium Lactate