Dynamic changes in cerebrospinal fluid pressure during neurosurgical operations

The effects of hyperventilation, osmotic and diuretic agents (urea, frusemide), thiopentone and succinylcholine chloride on the intracranial pressure were studied in neurosurgical patients with brain tumours. We have shown that hyperventilation together with osmotic and diuretic agents is very useful for reducing increased intracranial pressure.     

Effect of altering cerebrospinal fluid pressure on spinal cord blood flow

The outcome of patients with cholesterolosis was compared with that of those with chronic cholecystitis operated on for chronic acalculous biliary pain. A total of 55 patients with acalculous biliary pain with a median symptom duration of 24 (range 6-120) months were investigated by dynamic cholescintigraphy and followed for a median of 24 (range 12-60) months. Thirty-five patients underwent cholecystectomy, of whom 22 had a low gallbladder ejection fraction (under 35 per cent), with symptomatic improvement in 21 of these (P < 0.01). All four patients with a normal ejection fraction (35-50 per cent) improved after cholecystectomy but only four of nine with a high ejection fraction (over 50 per cent) did so. Results of histological examination were available in 32 patients and revealed cholesterolosis in 20. A low ejection fraction was found in 16 patients with cholesterolosis, of whom 15 showed symptomatic improvement after cholecystectomy; the other four patients had a high fraction and all improved after cholecystectomy. Overall, symptoms in 19 of 20 patients with cholesterolosis improved after cholecystectomy compared with only seven of 12 with chronic cholecystitis (P = 0.03).     

Lumbar cerebrospinal fluid drainage for prevention of cerebrospinal fluid fistulas

Leakage of cerebrospinal fluid may complicate surgical procedures of the temporal bone and skull base. This presentation details experience utilizing 7 days lumbar drainage in an attempt to prevent the occurrence of a postoperative CSF fistula. Thirty-nine patients underwent surgery for various intracranial pathologies and were felt to be at high risk for the development of postoperative CSF fistulae. None of the patients was given prophylactic antibiotics. Ten patients developed clinical and laboratory findings consistent with early meningitis and were treated with appropriate antibiotics. Three patients eventually developed a CSF fistula, with two resolving spontaneously and the third requiring a second surgical procedure to repair the dura (again using lumbar drainage postoperatively). Our conclusions suggest that prophylactic placement of a lumbar catheter in high risk patients increases the likelihood of successful dural closure with an acceptable morbidity. Is these patients routine antibiotic coverage is not indicated.     

Effect of sudden decompression on tissue pressure in the brain and the cerebrospinal fluid pressure

Extracranial hypertension was produced in cats by means of epidural compression with a baloon. After 2 hours of compression sudden decompression was performed and tissue pressure was compared at symmetrical sites of cerebral hemispheres with cerebrospinal fluid pressure measured in the cisterna magna. It was found that symmetrical tissue pystem, which was due probably to early oedema developing in the compressed area.     

Influence of urapidil on cerebrospinal fluid pressure in humans with uncompromised intracranial compliance

OBJECTIVE: Determine the influence of urapidil on mean lumbar cerebrospinal fluid pressure (CSFP), mean arterial pressure (MAP), mean central venous pressure (CVP) and heart rate (HR) in awake humans without any evidence of cerebral or cardiovascular disease. DESIGN: Open, single-dose volunteer study. INTERVENTIONS: CSFP was measured via a spinal needle after i.v. injection of a single dose of 0.2 mg kg-1 urapidil in six volunteers (2 female, 4 male). MEASUREMENTS AND RESULTS: After administration of urapidil, CSFP increased from 7 +/- 1 mmHg to 10 +/- 1 mmHg (p < 0.05), MAP decreased from 88 +/- 7 mmHg to 74 +/- 5 mmHg (p < 0.05), CPP decreased from 81 +/- 7 mmHg to 64 +/- 5 mmHg (p < 0.05) and CVP decreased from 0 +/- 1 mmHg to -3 +/- 1 mmHg (p < 0.05). CONCLUSION: Our data suggest that in humans with presumed normal intracranial compliance the administration of urapidil causes a small but statistically significant increase in CSFP due to a parallel decrease in MAP.     

Aldosterone secretion during high sodium cerebrospinal fluid perfusion of the brain ventricles

Conscious sheep with permanent indwelling cannulae in the lateral ventricles and the cisterna magna were Na depleted and then perfused for 9 h with an artificial CSF solution. There were 3 experimental groups: Group I (n=5) received perfusion with aritifical CSF containing NA 170 MEq./1, Group II (n=7) received perfusion with artificial CSF containing Na 145 mEq./1, Group III (n=7) received no perfusion. In Group I the blood aldosterone level fell from 26.4 +/- 7.4 to 8.6 +/- 2.3 ng/100 ml by 9 h after perfusion. There was no significant change in plasma [Na] or [K], blood angiotensin II or plasma renin concentration. Blood cortisol and corticosterone levels rose. There was also a fall in post-perfusion. Group III showed no significant change in blood aldosterone concentration. Multivariate statistical analysis showed that the fall in aldosterone levels during 170 mEq./l Na perfusion could not be accounted for by changes, either alone or together, of ACTH as evidenced by alteration in blood cortisol or corticosterone, or by change of plasma [Na], [K] or renin concentrations. This data supports the hypothesis of an additional factor which may be of CNS origin being involved in the control of aldosterone secretion.     

The effect of skull-pin insertion on cerebrospinal fluid pressure and cerebral perfusion pressure: influence of sufentanil and fentanyl

Directed delivery and distribution of anaesthetics (novocaine, lidocaine, trimecaine) immobilized on finely dispersed iron powders under the influence of an external magnetic field in body tissues of test animals have been studied. The data of emission spectral analysis relating to concentration of iron in soft and bone tissues of animals influenced by constant and alternating magnetic field on front and reverse sides over a period from 0 to 180 min are given.     

Increase in the chronically monitored cerebrospinal fluid pressure after experimental brain injury in rats

An enzyme-linked immunosorbent assay to detect thyroglobulin autoantibodies (TGAB) in canine serum was developed and validated. The test result for each sample was derived from the optical density readings (OD) and expressed as an Ab-score(%) calculated from three in-house calibrators. The assay specifically detected TGAB as judged from lack of response in the assay after samples had been incubated with specific antigen. Intra- and interassay coefficients of variation ranged from 2.0-4.9% and 4.6-9.9%, respectively. The detection limit, an Ab-score of 5.6%, was close to the median Ab-score of 10% observed in healthy dogs (n = 132). The median Ab-score of dogs with primary hypothyroidism and lymphocytic thyroiditis (n = 11), skin diseases (n = 35), and non-thyroidal diseases (n = 63) was 340%, 12%, and 8%, respectively. The prevalence of TGAB in hypothyroid dogs with lymphocytic thyroiditis (sensitivity) was 91% (95% confidence limits: 59%-99%). In dogs with dermatological diseases without lymphocytic thyroiditis the prevalence of TGAB was 3% corresponding to a specificity of 97% (95% confidence limit: 85%-100%). In dogs with non-thyroidal diseases and healthy dogs the prevalence of TGAB was 5% and 6%, respectively. The diagnostic accuracy of serum TGAB was evaluated by subjecting the data from 11 dogs with lymphocytic thyroiditis and 35 control dogs without lymphocytic thyroiditis to receiver-operating characteristic curve analysis. The area under the receiver-operating characteristic curve (W = 0.966; 95% confidence limit 87%-100%) was significantly higher than that of a worthless test (0.5) (P < 0.0001), thereby indicating that serum TGAB measurements distinguished between dogs with and without lymphocytic thyroiditis.     

Antibiotic pharmacodynamics in cerebrospinal fluid

The CSF half-lives of lipophilic agents, such as quinolones, are similar to those in serum and peak concentrations in CSF are achieved relatively quickly. In contrast, the pharmacokinetics of hydrophilic agents (beta-lactams and vancomycin) in CSF often differ from those in serum. In particular, the half-lives of these agents in CSF tend to be extended, and the time to achieve peak concentrations in CSF is delayed. Hydrophilic antibiotics, such as beta-lactams, penetrate poorly through the BBB, but CSF penetration is significantly increased in the presence of inflammation. In contrast, lipophilic antibiotics, such as quinolones, enter the CSF more efficiently and their penetration is not inflammation dependent. The pharmacodynamic properties of antibiotics in CSF are generally similar to those in other body sites; beta-lactam agents and vancomycin are time-dependent, whereas the quinolones and aminoglycosides are concentration-dependent. However, a notable difference from infections in other sites is that quinolones have a short PAE in CSF and need to continually exceed the MBC for maximal effectiveness. Thus, in CSF, quinolones demonstrate features of both concentration-dependency and time-dependency, evidence that the AUC/MBC is an important predictor of effectiveness. With the exception of quinolones, many antibiotics appear to have prolonged sub-MIC effects and longer half-lives in CSF than in serum, suggesting that dosing intervals longer than those used traditionally would be effective in meningitis. However, this requires clinical verification.     

Hyaluronan in human cerebrospinal fluid

We studied the concentration of hyaluronan in cerebrospinal fluid (CSF) in various diseases and attempted to define its reference interval. A radioassay utilizing cartilage proteins with affinity for hyaluronan was used in determining the concentration of 200 lumbar and 27 ventricular CSF specimens and 11 brain cyst fluids. Molecular weight distributions were determined by gel chromatography and localization in brain tissue by histochemistry. The hyaluronan level of lumbar CSF showed an increase with age; comparatively healthy children had (mean +/- SD) 50 +/- 41 micrograms/L (n = 40) and adults 166 +/- 77 micrograms/L (n = 9); i.e. significantly different values. The highest level was recorded in a patient with meningitis (> 8000 micrograms/L). More than 4000 micrograms/ L was noted in a patient with tumour metastasis in the cerebellum. Significantly elevated levels were especially found with spinal stenosis, head injury and cerebral infarction, but also in inflammatory medical disorders, hydrocephalus and encephalitis. We found no significant increase in multiple sclerosis and some other neurological diseases. Ventricular CSF of adults contained significantly less hyaluronan (53 +/- 73 micrograms/L; n = 16) than lumbar CSF. Hyaluronan in cyst fluids varied from 31 to 25,000 micrograms/L. Weight average molecular weight of hyaluronan in CSF was 2.9-3.0 x 10(5) and in brain tumour cyst fluid 2.4 x 10(6). In search for the origin of hyaluronan in CSF it was found that its concentration in the choroid plexus and leptomeninges was low, but that hyaluronan was accumulated in the superficial layer of the cerebral cortex. Continued screening for hyaluronan in CSF may be valuable in cases of inflammatory diseases, tumours and obstruction to CSF flow.     

Rate of cerebrospinal fluid formation, resistance to reabsorption of cerebrospinal fluid, brain tissue water content, and electroencephalogram during desflurane anesthesia in dogs

Propofol decreases intraocular pressure (IOP) and the IOP response to laryngoscopy and intubation, but the mechanisms responsible for this effect have not been reported. The present study examined the effect of propofol on IOP, intraocular fluid formation and outflow facility, and intraocular compliance. Twenty-two white New Zealand rabbits were anesthetized with halothane (0.8%-1.0% inspired concentration) in nitrous oxide (2 L/min) and oxygen (1 L/min). Muscle paralysis was established with pancuronium, and the lungs were mechanically ventilated through a tracheal tube. Twelve rabbits examined under these conditions served as controls. In the treatment group (n = 10), 6 mg/kg propofol followed by 18 mg.kg-1 x h-1 propofol intravenously was added to halothane/nitrous oxide/oxygen anesthesia. In both groups, a series of intraocular infusions was made via a 30-gauge needle in the anterior chamber, and IOP, the rate of aqueous humor formation (Fa), and trabecular outflow facility (Ctr) were determined using conventional analysis. These same measures, as well as intraocular compliance, were determined using a new method of analysis adapted from the manometric technique for determining cerebrospinal fluid dynamics. IOP was 11.3 +/- 1.8 mm Hg (mean +/- SD) in halothane-anesthetized controls and decreased to 9.4 +/- 2.2 mm Hg when propofol was added to halothane anesthesia (P < 0.05). By conventional analysis, Fa was 2.82 +/- 0.94 microL/min and Ctr was 0.121 +/- 0.044 microL.min-1 x mm Hg-1 in controls. After addition of propofol, Fa decreased by 24% to 2.15 +/- 0.62 microL/min (P < 0.05) and Ctr decreased by 18% to 0.099 +/- 0.034 microL.min-1 x mm Hg-1 (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Gram-negative cerebrospinal fluid shunt-associated infections

Twenty hydrocephalic children with cerebrospinal fluid (CSF) shunts over an 11-year period were seen with Gram-negative central nervous system (CNS) infections. Seventeen infections were with single organisms and three were mixed. Sixteen of 20 (80%) of the infections occurred within five months of shunt surgery. Complete shunt removal or replacement in a new site plus systemic and intraventricular antibiotics resulted in a 100% (9/9) cure rate. Systemic and intraventricular antibiotics alone or in combination with incomplete shunt removal generally were unsuccessful. Significant morbidity and mortality were associated with these infections. Of the 18 patients with follow-up data, seven (39%) died with the infection, four (22%) sustained definite CNS damage, three (17%) were retarded after infection but their preinfection status was unknown, and only four (22%) patients escaped without definite sequela. Early recognition and appropriate therapy, hopefully, will improve the current bleak prognosis     

Penicillin transport from cerebrospinal fluid

The passage of penicillin G from cerebrospinal fluid (CSF) was studied by continuous ventriculocisternal perfusion in conscious rabbits. The concentration of penicillin G in the perfusate, collected from the cisterna magna, was 76.5 percent +/- 1.0 (SEM) of that entering the ventricles (having adjusted for normal secretion of CSF). The mean concentration of penicillin G rose 15 percent (p less than 0.005) in the cisternal CSF after probenecid (2 mg per milliliter) was added to the perfusion fluid. We conclude that an active transport system removes penicillin G from the CSF; this mechanism can be inhibited by intraventricular probenecid. Our results are in accord with observations deriving from studies on anesthetized animals given probenecid intravenously or intraperitoneally.     

Assay of gentamicin in cerebrospinal fluid

A comparison of standard curves obtained from a conventional plate diffusion assay method revealed significant differences when gentamicin standards were made up in different media. Standards made up in distilled water resulted in a curve which differed from that of standards made up in pooled human cerebrospinal fluid by a factor of up to 4. When the assay medium was supplemented with 0-5% sodium chloride, the difference between the two standard curves was reduced to a factor of about 1-5. The curve obtained from standards made up in 150 mM sodium chloride/4-5 mM calcium chloride correlated well with that from standards made up in cerebrospinal fluid. There was no evidence of gentamicin being bound to protein in the cerebrospinal fluid.     

Protein accumulation in cerebrospinal fluid during -90 degrees head-down tilt in rabbit

Plasma proteins are only somewhat larger than the intercellular spaces of the cerebral microvessels that constitute the blood-brain barrier or of the choroid plexus villi that elaborate cerebrospinal fluid (CSF). We hypothesized that the integrity of these barriers in anesthetized rabbits might be compromised during head-down tilt (HDT). Plasma protein and osmolality, hematocrit, and CSF protein concentration were compared in rabbits exposed to 1 h of HDT (n = 20) and prone rabbits (n = 10). In addition, the concentration of trypan blue dye, injected intravenously at the end of HDT or the prone position, was measured in brain homogenate. Finally, arterial blood pressure was measured via a catheterized carotid artery. HDT disrupted the barrier between blood and CSF, as indicated by a significantly (P < 0.01) greater brain trypan blue concentration in the HDT rabbits [172.2 +/- 14.4 (SD) micrograms/g dry wt] than in the prone rabbits (29.8 +/- 4.4 micrograms/g dry wt). Moreover CSF protein 5 min after HDT onset was significantly increased compared with control in HDT rabbits (54.6 +/- 1.9 vs. 81.4 +/- 5.2 mg/dl; n = 8) but not in prone rabbits (55.6 +/- 2.7 vs. 57.2 +/- 5.0 mg/dl; n = 6). Changes in the plasma protein-to-hematocrit ratio in the HDT animals, but not in the prone animals, were also compatible with a loss of fluid from the vascular compartment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Idiopathic normal pressure hydrocephalus: analysis of factors related to cerebrospinal fluid dynamics determining functional prognosis

OBJECTIVE: To examine the effect of maternal smoking on the relationship between maternal hemoglobin levels and pregnancy outcome. DESIGN: A prospective study of healthy parous women from early pregnancy and of their infants. SETTING: Three Scandinavian university hospitals covering all deliveries from well defined geographical areas. SUBJECTS: Smoking (669) and non-smoking (368) mothers, para 1 and 2 and with > or = 37 weeks of gestational length. MAIN OUTCOME MEASURES: Birth weight and placental weight. Ponderal Index and Placental Index as measures of possible discordant fetal and placental growth. RESULTS: In non-smoking mothers the hemoglobin levels in the three trimesters had no relation to birth weight. In smoking mothers a significantly lower birth weight was seen with a high hemoglobin level in the third trimester, but hemoglobin levels in early or mid-pregnancy had no association to birth weight. Smoking mothers also had a significantly greater fall in hemoglobin concentration from first to second and third trimester as compared to non-smokers although ferritin levels were similar in smokers and non-smokers, implying similar iron stores. The ratio of placental weight to the weight of the newborn was significantly higher in smokers, but no association was found to different hemoglobin levels. CONCLUSIONS: Fetal growth impairment associated with maternal smoking is even more pronounced in smoking mothers with high hemoglobin levels in late pregnancy. Smoking mothers were also found to have disproportional fetal/placental growth with relatively high placental weights. In non-smoking mothers hemoglobin levels had no relation to birthweight.     

Simultaneous recording of cerebrospinal fluid pressure and middle cerebral artery blood flow velocity in patients with suspected symptomatic normal pressure hydrocephalus

Whether anaphylactic histamine release from rat peritoneal mast cells is influenced by betahistine, a histamine H1-receptor agonist/H3-antagonist, and dimaprit, an H2-agonist, was examined. Treatment with dimaprit at 6 and 60 microM for 20 min significantly inhibited the anaphylactic histamine release, whereas betahistine at up to 80 microM under the same conditions did not affect it. Treatment with dimaprit at 6 and 60 microM for 1 to 20 min and for 5 to 20 min, respectively, caused a time-dependent inhibition of the release, but up to 30 min treatment with 8 and 80 microM betahistine had no effect. The decreased histamine release induced by dimaprit was recovered by neither mepyramine nor cimetidine. However, thioperamide, an H3-selective antagonist, dose-dependently restored the diminished release. From these results, the inhibition of anaphylactic histamine release by dimaprit is not produced by the stimulation of H2-receptors, but involves the stimulation of H3-like receptors or H3-subtype receptors, which are distinct from the H3-receptors located in brain, and suggests that the receptor plays an important role in the negative feedback regulation of histamine release.