Cerebrospinal fluid production rate in various pathological conditions: a preliminary study.

INTRODUCTION: The cerebrospinal fluid (CSF) production rate in humans is not clearly defined but is estimated to be 18-24 ml/h (Trevisi et al Croat Med J 55(4):377-387 (24); Casey and Vries Childs Nerv Syst 5(5):332-334 (8)). A frequent clinical observation is that patients often drain higher volumes of CSF than can be explained by the assumed 'normal' CSF production rate (PRcsf). In the National Hospital for Neurology and Neurosurgery PRcsf was recorded in a variety of common neurosurgical pathologies using LiquoGuard7, an automated peristaltic pump that accurately controls CSF drainage and maintains a pre-set CSF pressure. METHODS: A prospective observational study was performed from September 2021 onwards, on all patients in the National Hospital for Neurology and Neurosurgery who required CSF drainage as part of their ongoing treatment. The external drain was connected to a LiquoGuard7 pump (Möller Medical GmbH, Fulda, Germany), and the internal software of LiquoGuard7 was used to measure PRcsf. Statistical analysis used SPSS (version 25.0, IBM) by paired t test, comparing measured rates to hypothetical 'normal' CSF production rates calculated and published by Ekstedt (16-34ml/h) (Ekstedt J Neurol Neurosurg Psychiatry 41(4):345-353 (14)), assuming a similar distribution. RESULTS: PRcsf was calculated in 164 patients. Suspected normal pressure hydrocephalus (n=41): PRcsf of 79ml/h±20SD (p<0.0001). Post-surgical CSF leak (n=26): PRcsf of 90ml/h±20SD (p<0.0001). Subarachnoid haemorrhage (n=34): PRcsf of 143ml/h±9SD (p<0.0001). Intracerebral haemorrhage (n=22): PRcsf of 137ml/h±20SD (p<0.0001). Spinal lesions (n=7): PRcsf of 130ml/h±20SD (p<0.0032). Pituitary adenomas (n=10): PRcsf of 29 ml/h±9SD (p<0.049). Idiopathic intracranial hypertension (n=15): PRcsf of 86ml/h±10SD (p<0.0001). Decompensated long-standing overt ventriculomegaly (n=4): PRcsf of 65ml/h±10SD (p<0.0001). Cerebral infection (n=5): PRcsf of 90ml/h±20SD (p<0.0001). CONCLUSION: Net CSF production rate may be higher than expected in many conditions, as measured with new device LiquoGuard7 through the study of net flow rate, which may have implications for clinical decisions on CSF diversion. The conventional understanding of CSF production and circulation does not explain the findings of this study. More extensive studies are needed to validate this technique.

External ventricular drain management in subarachnoid haemorrhage: a systematic review and meta-analysis.

External ventricular drainage (EVD) is one of the most commonly performed neurosurgical procedures. Despite this, the optimal drainage and weaning strategies are still unknown. This PRISMA-compliant systematic review and meta-analysis analysed the outcomes of patients undergoing EVD procedures, comparing continuous versus intermittent drainage and rapid versus gradual weaning. Four databases were searched from inception to 01/10/2020. Articles reporting at least 10 patients treated for hydrocephalus secondary to subarachnoid haemorrhage were included. Other inclusion criteria were the description of the EVD drainage and weaning strategies used and a comparison of continuous versus intermittent drainage or rapid versus gradual weaning within the study. Random effect meta-analyses were used to compare functional outcomes, incidence of complications and hospital length of stay. Intermittent external CSF drainage was associated with lower incidence of EVD-related infections (RR = 0.20, 95% CI 0.05-0.72, I-squared = 0%) and EVD blockages compared to continuous CSF drainage (RR = 0.45, 95% CI 0.27-0.74, I-squared = 0%). There was no clear advantage in using gradual EVD weaning strategies compared to rapid EVD weaning; however, patients who underwent rapid EVD weaning had a shorter hospital length of stay (SMD = 0.34, 95% CI 0.22-0.47, I-squared = 0%). Intermittent external CSF drainage after SAH is associated with lower incidence of EVD-related infections and EVD blockages compared to continuous CSF drainage. Patients who underwent rapid EVD weaning had a shorter hospital length of stay and there was no clear clinical advantage in using gradual weaning.

Outcome improvement in cerebral ventriculitis after ventricular irrigation: a prospective controlled study.

OBJECTIVE: Cerebral ventriculitis remains one of the most challenging neurosurgical conditions, with poor outcome and a long course of treatment and duration of hospital stay. Despite the current conventional management plans, i.e., using antibiotics in addition to CSF drainage, the outcome remains unsatisfactory in some cases, with no definitive therapeutic guidelines. This study aims to compare the outcome of ventricular irrigation/lavage (endoscopic irrigation or the double-drain technique) to conventional currently accepted therapy using just drainage and antibiotics. METHODS: The authors conducted a prospective controlled study in 33 patients with cerebral ventriculitis in which most of the cases were complications of CSF shunt operations. Patients were divided into two groups. Removal of the ventricular catheter whenever present was performed in both groups. The first group was managed by ventricular lavage/irrigation, while the other group was managed using conventional therapy by inserting an external ventricular drain. Both systemic and intraventricular antibiotics were used in both groups. The outcomes were compared regarding mortality rate, modified Rankin Scale (mRS) score, and duration of hospital stay. RESULTS: The mean age of the study population was 5.98 ± 7.02 years. The mean follow-up duration was 7.6 ± 3.2 months in the conventional group and 5.7 ± 3.4 months in the lavage group. The mortality rate was 25% (4/16) in the lavage group and 52.9% (9/17) in the nonlavage group (p = 0.1). The mRS score was less than 3 (good outcome) in 68.8% (11/16) of the lavage group cases and in 23.5% (4/17) of the conventional group (p < 0.05). The mean hospital stay duration was 20.5 ± 14.2 days in the lavage group, whereas it was 39.7 ± 16.9 days in the conventional group (p < 0.05). CONCLUSIONS: Ventricular lavage or irrigation together with antibiotics is useful in the management of cerebral ventriculitis and associated with a better outcome and shorter hospital stay duration compared to current conventional lines of treatment.