[Acid-base balance and electrolytes in cerebrospinal fluid of patients with bacterial and lymphocytic meningitis]. / Równowaga kwasowo-zasadowa i elektrolity plynu mózgowo-rdzeniowego u chorych na ropne i limfocytarne zapalenie opon mózgowo-rdzeniowych.

Acid-base balance and electrolytes concentration in cerebrospinal fluid (CSF) of patients with bacterial and lymphocytic meningitis were assessed. Inflammatory process causing the damage of blood-brain barrier and brains hypoxia leads to statistically significant changes of pH, pO2, bicarbonates and K+ concentrations in CSF of patients with bacterial meningitis, which in lymphocytic meningitis were not observed. Patients with fatal; outcome of bacterial meningitis showed higher CSF's acidosis and lover bicarbonates with higher K+ concentrations, which suggest deeper damage of brain hemostasis regulating mechanisms in those patients.

Elevated CSF lactate in the Rett syndrome: cause or consequence?

We report values for CSF and blood lactate and acid-base balance in 8 girls with the Rett syndrome and correlate the findings with respiratory dysfunction. Three patients had elevated CSF lactate values; their hyperventilation (HV) was so intensive that the acid-base balance showed respiratory alkalosis with an abnormally low base excess. One of these three patients had normal CSF lactate and acid-base balance before she developed HV. Two patients were so young that they had not yet developed HV and their CSF lactate values were normal. One patient had elevated CSF lactate when she was younger and her HV was more intensive, but now her CSF and blood lactate were normal; her acid-base balance showed mild hypocapnia but was otherwise normal. Thus, in the Rett syndrome, CSF lactate elevation seems to be a secondary phenomenon connected with the intensive HV and alkalosis rather than a sign of any mitochondrial disorder.

[Acid-base equilibrium of cerebrospinal fluid in inflammatory diseases of the central nervous system]. / Stan równowagi kwasowo-zasadowej plynu mózgowo-rdzeniowego w chorobach zapalnych osrodkowego ukladu nerwowego.

In 51 patients with meningoencephalitis the acid-base equilibrium of the cerebrospinal fluid (CSF) was assessed. In the fluid the following gasometry parameters were determined: pH, pCO2, pO2 and HCO3-, and also the levels of lactic acid, ATP, pyruvic acid, and sodium and potassium ion concentrations. The control group included 13 patients in whom on the basis of CSF examination, inflammatory disease of the central nervous system was ruled out. The results were analysed in groups of patients with purulent and lymphocytic meningitis. The changes were taken into account of the determined parameters in the course of the disease as well as their relationship with clinical condition of the patients. The differences were found in the values of acid-base equilibrium parameters of the CSF between purulent and lymphocytic meningitis. The differences of the values of the determined parameters between the patients in the group of purulent meningoencephalitis depended on their clinical condition and the outcome of the pathological process. In patients with purulent meningoencephalitis metabolic, lactic acidosis of the CSF occurred which was statistically significantly higher than in the group of patients with lymphocytic meningitis. The lowest values of pH and HCO3- concentration and the highest concentrations of lactic and pyruvic acids and potassium ion levels were found in the group of patients with purulent meningoencephalitis. The highest degree of acid-base equilibrium disturbances in the CSF was observed in the subgroup of patients with purulent meningoencephalitis who died.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of metabolic arterial pH changes on medullary ecf pH, csf pH and ventilation in peripherally chemodenervated cats with intact blood-brain barrier.

Brain ecf and csf pH are regulated within narrow limits. In the present study we investigated whether--with an intact blood-brain barrier (bbb)--during acute (isocapnic) metabolic pHa disturbances, brain ecf and csf pH changes occur in the same direction as plasma pH. Experiments were performed in 4 ventilated, vagotomized, and in 17 spontaneously breathing cats. Medullary ecf pH and csf pH were measured with flat pH electrodes. Metabolic pHa disturbances were induced by isocapnic i.v. infusions of HCl and NaHCO3, and by non-isocapnic i.v. bolus injections of NaHCO3. In all cats both sinus nerves were cut. We found that: (1) during acute pHa changes, medullary ecf pH changes rapidly in the same direction despite an intact bbb (no extravasation of Evans Blue); (2) the time courses of the ecf and csf pH responses to a bolus injection of NaHCO3 are quite different: after an initial short (less than 10 sec) decrease, the ecf pH rapidly increases above control, whereas the csf pH shows a rapid and long lasting acidic response; (3) ventilation showed a biphasic response pattern to a NaHCO3 bolus: an initial increase followed by a slow decrease to about control level. It was argued that this response cannot be explained by the observed ecf or csf pH responses alone.

Ionic mechanisms of cerebrospinal fluid acid-base regulation.

This review emphasizes the importance of strong ions in the regulation of cerebrospinal fluid (CSF) acid-base balance. In a solution like CSF that is devoid of nonbicarbonate buffers. [H+] and [HCO-3] are dependent variables, the independent variables being the CO2 partial pressure (PCO2) and the strong ion difference. Any measureable changes in CSF [HCO-3] and any change in [H+] that occur independent of changes in PCO2 must be accompanied by, if not caused by, changes in strong ions. The role of H+ and HCO-3 vs. strong ions in the ionic mechanisms of CSF acid-base regulation is unknown. For example, these mechanisms could depend only on changes in strong ions that accompany acid-base disorders, or they could be triggered by changes in [H+] or PCO2. These ideas are presented within the context of current concepts concerning the relationship of CSF to brain interstitial fluid (ISF) and the importance of choroid plexus and blood-brain barrier mechanisms in determining CSF and ISF ionic composition. Studies concerning CSF strong ions in normal and abnormal acid-base states are reviewed.

Electrolyte composition of cerebrospinal fluid in acute acid-base disorders.

Electrolyte composition of cisternal CSF was measured during 4 hours of respiratory and metabolic acid-base disturbance in anesthetized dogs. Three groups of dogs were studied: (1), isocapnic metabolic alkalosis; (2), acute respiratory acidosis; and (3), combined respiratory acidosis and metabolic alkalosis. Cisternal CSF [K+] remained unchanged despite significant changes in plasma [K+], PCO2 and [HCO3-]; suggesting that mechanisms involved in regulation of CSF [K+] continue to operate normally under such conditions. Cisternal [Na+] and osmolality remained unchanged with almost identical reciprocal equimolar changes in CSF concentration of Cl- and HCO3- during the acid-base disorders studied. The regulatory mechanisms involved in this Cl- -HCO3- exchange may be different in different acid-base disorders, but since CSF [Na+] is kept constant, CSF [HCO3-] in any acid-base disorder equals the difference between CSF [Na+] and CSF [Cl-].

Cerebrospinal fluid acid-base balance in patients with severe injuries living at an altitude of 1 660 metres.

Cerebrospinal fluid (CSF) acid-base balance in 40 control subjects and 40 patients with head injuries was studied at an altitude of 1 660 m. The patients with head injuries showed a significantly lower CSF pH associated with a fall in CSF bicarbonate and an elevation of CSF lactic acid. The cause of these observations is unclear, but it is proposed that this may be related to the relative hypoxaemia associated with an altitude of 1 660 m.

Acid-base and gas tension of cerebrospinal fluid in Nigerians and tetanus patients.

The acid-base balance and gas tension of the cerebrospinal fluid of eight tetanus patients and twelve control subjects were studied. Tetanus patients had metabolic acidosis which was severely reflected in the cerebrospinal fluid. While the cerebrospinal fluid pH is lower than that of the arterial blood there was no difference between the acid-base and gas tension of the cerebrospinal fluid of Nigerians and the causasians. The severe metabolic acidosis of the cerebrospinal fluid of tetanus patients might be one of the causes of sudden deaths seen in these patients.

Intracellular pH of brain: alterations in acute respiratory acidosis and alkalosis.

To evaluate the metabolic adaptations of the brain to acute respiratory acid-base disturbances, a method was developed to measure intracellular pH (pHi) in the brain of dogs under conditions in which arterial pH is rapidly altered. Brain pHi was determined by measuring the distribution of 14C-labeled dimethadione (DMO) in brain relative to cortical CSF. Brain extracellular space (ECS) was evaluated as the 35SO4 = space relative to cortical CSF, and arterial Po2 was maintained at 82-110 mmHg. In normal dogs, brain (cerebral cortex) pHi was 7.05, and after 1 h of hypercapnia (arterial pH = 7.07) it fell to 6.93. However, after 3 h with arterial Pco2 maintained at 85 mmHg brain pHi was normal (7.06), and during this time brain bicarbonate had risen from 11.3 to 24.4 meq/kg H2O. These changes were not prevented by intravenous doses of acetazolamide,

Dynamic changes in regional CBF, intraventricular pressure, CSF pH and lactate levels during the acute phase of head injury.

The authors measured regional cerebral 133xenon (133Xe) blood flow (rCBF), intraventricular pressure (IVP), cerebrospinal fluid (CSF) pH and lactate, systemic arterial blood pressure (SAP), and arterial blood gases during the acute phase in 23 comatose patients with severe head injuries. The IVP was kept below 45 mm Hg. The rCBF was measured repeatedly, and the response to induced hypertension and hyperventilation was tested. Most patients had reduced rCBF. No correlation was found between average CBF and clinical condition, and neither global nor regional ischemia contributed significantly to the reduced brain function. No correlation was found between CBF and IVP or CBF and cerebral perfusion pressure (CPP). The CSF lactate was elevated significantly in patients with brain-stem lesions, but not in patients with "pure" cortical lesiosn. The 133Xe clearance curves from areas of severe cortical lesions had very fast initial components called tissue peaks. The tissue peak areas correlated with areas of early veins in the angiograms, indicating a state of relative hyperemia, referred to as tissue-peak hyperemia. Tissue-peak hyperemia was found in all patients with cortical laceration or severe contusion but not in patients with brain-stem lesions without such cortical lesions. The peaks increased in number during clinical deterioration and disappeared during improvement. They could be provoked by induced hypertension and disappeared during hyperventilation. The changes in the tissue-peak areas appeared to be related to the clinical course of the cortical lesion.

[Acid-base equilibrium in cerebrospinal fluid following intracranial surgery]. / Równowage kwasowo-zasadowa w plynie mózgowo-rdzeniowym u chorych po zabiegach sródczaszkowych

In 48 patients the acid-base equilibrium in the CSF and blood was determined on the 2nd day after intracranial operation. In the postopertive period various disturbances of this equilibrium were found which were probably various stages of metabolic acidosis compensation in the CSF which was a reflection of metabolic (lactate) acidosis developing primarily in the damaged brain area. On the basis of determinations it was found that changes in the CSF of the type of metabolic acidosis (21 cases) corresponded most frequently to respiratory alkalosis in the blood (11 cases). Changes of the type of respiratory acidosis in the CSF(13 cases) corresponded usually to metabolic alkalosis in the blood (7 cases). The development of metabolic acidosis in patients in severe and moderately severe condition (19 cases) was associated with poor prognosis as to survival since the mortality in this group was 10 (about 53%). The favourable effect of dehydrating treatment may be due also to facilitation of passage of bicarbonates from the blood into the cerebral tissue and CSF since their level is increased in the blood during metabolic alkalosis (during a decrease in the extracellular space) resulting from dehydration.