Biomedical subjects

A D Fremming

Publications and source records attributed to A D Fremming.

4 recordsLinked to original sources

PubMed2004

A prospective study on the clinical effect of surgical treatment of normal pressure hydrocephalus: the value of hydrodynamic evaluation.

The effect of surgical treatment of patients with normal pressure hydrocephalus (NPH) is reported to be variable. Candidates for surgery have often been selected using hydrodynamic tests; however, the predictive value of such tests remains uncertain. Seventeen patients with idiopathic NPH underwent continuous computerized intracranial pressure (ICP) monitoring and a steady state lumbar infusion test determining the resistance to cerebrospinal outflow (R(out)). The patients were treated surgically and clinically re-examined approximately 6 months postoperatively using a new NPH score. The effect of surgical treatment was good. The R(out) was positively correlated with the clinical state of the patients before treatment. After surgery, the R(out) correlated well with the improvement in gait and NPH score. Ventricular size was negatively correlated with hydrodynamic variables before treatment. Surgery reduced the ventricular size only slightly and the degree of reduction was linked to the R(out). ICP measurements could not predict outcome in NPH cases.

Adult↗

PubMed2003

A computer-based method for comparisons of continuous intracranial pressure recordings within individual cases.

BACKGROUND: This study assessed two strategies of comparing continuous intracranial pressure (ICP) recordings within individual cases, namely either by calculation of differences in mean ICP or by calculation of differences in numbers of ICP elevations. METHODS: Continuous ICP recordings before and after cranial surgery were both presented as mean ICP and as numbers of ICP elevations of different levels (20 and 25 mmHg lasting either 0.5 or 1 minute). Since the length of pressure recordings differed somewhat between individuals, the numbers of ICP elevations were standardised by computing the numbers of elevations during a 10 hours period. The ICP recordings were analysed by the Sensometrics Pressure Analyser software. The ICP curves included here were selected from a group of 15 children undergoing calvarial expansion surgery for craniosynostosis, in whom continuous ICP monitoring was performed both before and after surgery as part of the diagnostic workout to rule out lasting intracranial hypertension. FINDINGS: After surgery, mean ICP during sleep was reduced by 5 mmHg or more in 5 cases, minimally changed (i.e. 2 mmHg or less) in 6 cases, and variably increased in the other 4 cases. In one of these 4 latter cases, numbers of ICP elevations were increased after surgery, but in all other 14 cases the numbers of ICP elevations were significantly reduced. Reduction of mean ICP by more than 2 mmHg associated with good outcome was observed in 3 of 15 cases (20%), whereas marked and significant reductions in numbers of ICP elevations during sleep combined with good outcome was observed in 12 of 15 cases (80%). INTERPRETATION: Outcome after the 2nd ICP monitoring was more reliably predicted by computing differences in numbers of ICP elevations than by calculation of mean ICP.

Adolescent↗

PubMed2003

Lack of relationship between resistance to cerebrospinal fluid outflow and intracranial pressure in normal pressure hydrocephalus.

OBJECTIVE: To explore whether calculation of resistance to cerebrospinal fluid (CSF) outflow (Rout) by the lumbar constant rate infusion test in a reliable way predicts the intracranial pressure (ICP) profile in normal pressure hydrocephalus (NPH). METHODS: A prospective study was undertaken including 16 cases with clinical signs of normal pressure hydrocephalus that were investigated with both continuous ICP monitoring and the lumbar constant rate infusion test. Intracranial pressure monitoring was performed for about 24 h, and supplied with a simultaneous lumbar constant rate infusion test at the end of the monitoring period. The pressure recordings were analysed using the Sensometrics Pressure Analyser. Various characteristics of the pressure curves were compared. RESULTS: The continuous ICP recordings were considered as normal (mean ICP<11.5 mmHg) in all 16 cases. The lumbar infusion test showed an apparently abnormal resistance to CSF outflow (Rout) (> or =12.0 mmHg/ml/min) in 12 of 16 cases. There was no relationship between lumbar Rout and mean ICP during sleep. We could not find any relationship between lumbar Rout and number of nightly ICP elevations of 1525 mmHg lasting 0.5 or 1 min. Neither resistance to CSF outflow (Rout) nor mean ICP during sleep was related to the ventricular size. CONCLUSIONS: The results of this prospective study revealed no significant relationship between resistance to CSF outflow (Rout) and the ICP profile in NPH cases. The results also suggest that caution should be made when predicting the ICP profile on the basis of measuring the lumbar CSF pressure for a few minutes duration.

Adult↗

PubMed2001

A new method and software for quantitative analysis of continuous intracranial pressure recordings.

OBJECTIVE: A computer software utilising a new method for quantitative analysis of intracranial pressure (ICP), was developed to provide a more accurate analysis of continuously recorded ICP. Intracranial pressure curves were analysed by the software to explore the relationship between mean ICP and the presence of ICP elevations. METHODS: The Sensometrics Pressure Analyser (version 1.2) software provides a quantitative analysis of the ICP curve, presenting the ICP recordings as a matrix of numbers of ICP elevations of different levels (e.g. 20 or 30 or 40 mmHg) and durations (e.g. 0.5, 5 or 10 minutes). The number of ICP elevations may be standardised by calculating the number of elevations during for instance a 10 hour period. The computer software was used to retrospectively analyse the ICP curves in our first consecutive 127 patients undergoing continuous 24 hours ICP monitoring during the two-year period from February 1997 to December 1998. The indications for ICP monitoring were suspected hydrocephalus, craniosynostosis or shunt failure. RESULTS: Analysis of the ICP curves revealed a rather weak relationship between mean ICP and the number of apparently abnormal ICP elevations (that is elevations of 20 mmHg or above). Abnormal ICP elevations were present in a relatively high proportion of cases with a normal mean ICP below 10 mmHg, or a borderline mean ICP between 10 and 15 mmHg. In addition, the ICP data of two cases are presented suggesting that mean ICP may be an inaccurate measure of ICP. CONCLUSIONS: The results of analysing ICP curves by means of this method and software reveal that calculation of ICP elevations of different levels and durations may represent a more accurate description of the ICP curve than calculation of mean ICP. The method may enhance the clinical application of ICP monitoring.

Adolescent↗