13. Volume-pressure infusion tests: Typical patterns of infusion studies in different forms of CSF circulatory disorders.

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1 13. Volume-pressure infusion tests: Typical patterns of infusion studies in different forms of CSF circulatory disorders.

2 Hydrocephalus is far more complex than disorder of CSF circulation CSF circulation altered? Clinical axis Clinical symptoms of hydrocephalus Cerebral blood flow altered? Which are reasons and which are effects? What are weights? Does this naive scheme depend on time? Age? Aetiology?

3 CSF dynamics testing -measurement techniques: 1. Perfusion study 2. Infusion test 3. Bolus injection 4. Constant pressure test ICP HR AMP

4 Infusion test: Measurement set-up

5 Infusion test trolley: pressure amplifier. Infusion pump, computer+ software Infection rate (200 tests/year): 0.8% %-2009

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7 What we measure: mean ICP, heart rate, pulse amplitude of ICP and RAP index ICP HR AMP RAP

8 Full identification of cerebrospinal compensation: Identification of the model

9 Additional information: detection of the lower breakpoint of AMP/P characteristic

10 Infusion test: written protocol Tests Results: [ CSF Infusion Test ] ICP baseline [mmhg] ICP plateau [mmhg] AMP baseline [mmhg] 0.52 AMP plateau [mmhg] 1.67 Rcsf [mmhg*min/ml] Elasticity [1/ml] 0.48 PVI [ml] 4.79 Pss [mmhg] CSF production rate [ml/min]0.17 Volume infused [ml] Infusion duration [min] Normalised Error [%] Shunt critical ICP [mmhg] Shunt resist. [mmhg*min/ml] 3.30

11 Different technique servo-controlled multiple stage infusion study University of Umea, Sweden and

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13 One needle infusion: Czosnyka M, Whitehouse H, Smielewski P, Simac S, Pickard JD: Testing of cerebrospinal compensatory reserve in shunted and non-shunted patients: a guide to interpretation based on observational study. J Neurol Neurosurg and Psychiatry 1996; 60:

14 Examples of infusion studies in different types of hydrocephalus Normal CSF circulation: Rcsf =8.6 ; opening pressure 6 mm Hg

15 NPH: normal opening pressure, increased Rcsf, slow waves, pulse amplitude well correlated with mean ICP

16 Atrophic brain

17 Acute hydrocephalus post SAH

18 IIH ICP baseline [mmhg] ICP plateau [mmhg] AMP baseline [mmhg] 2.73 AMP plateau [mmhg] 3.61 Rcsf [mmhg*min/ml] 4.23 Elastance [1/ml] 0.11

19 Summary: Who needs a shunt (from CSF dynamics perspective)? He needs! She needs!!! She does not!!! He does not need, observation!

20 Vasogenic waveforms of ICP before and during constant rate infusion study

21 S.Momjian et al., Cambridge 2002: All vasogenic waveforms increased in magnitude during the test:

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24 Test with plateau wave. Easily controlled with CSF drainage

25 Post-SAH: Monitoring; high dynamics of ICP

26 TCD during infusion study good synchronization of B waves in ICP and FV

27 Autoregulation is worse in patients with lower Rcsf

28 Non-invasive ABP during infusion test

29 PRx in non-shunted patients Rcsf [mmhg/(ml/min)] R=-0.5; p< PRx

30 Near Infrared Spectroscopy durin Infusion Test 18 infusion tests; 17 patients. ICP, ABP, TCD (10 good recordings) and NIRS Average increase in ICP from 9 to 17 mm Hg, 9 tests with ICP>= 20 mm Hg Average decrease in CPP by 3 mm Hg, NIRS and FV no reaction

31 Rhythmic slow waves of ICP, NIRS, TCD and ABP ( periods 20 sec to 3 minutes) Thanks to Dr.R. Weerakkody

32 Thanks to Dr.R. Weerakkody

33 Slow waves in ICP and ABP are phase-shifted, in ICP and Hb in phase Thanks to Dr.R. Weerakkody

34 Relative change in magnitude of slow waves in ICP and Hb are correlated!!!! Thanks to Dr.R. Weerakkody

35 Thanks to Mr.S.Momjian

36 Periventricular white matter analysis Slices at the level of the lateral ventricles and above the caudate nucleus (no intervening grey matter to the cortex) White matter segmented to exclude cortical grey matter Ventricles segmented Only the white matter on the lateral aspect of the ventricles retained Thanks to Mr. S.Momjian

37 Momjian S, Owler BK, Czosnyka Z, Czosnyka M, Pena A, Pickard JD. Pattern of white matter regional cerebral blood flow and autoregulation in normal pressure hydrocephalus. Brain May;127(Pt 5): NPH NORMAL CBF in white matter in NPH decreases as a function of distance from the surface of ventricles. In normal volunteers distribution of CBF is flat Autoregulation is worse closer to surface of ventricles than further away from ventricles (SRoR= static rate of autoregulation, SRoR=100%- good autoregulation; SRoR=0%- disturbed autoregulation)

38 Early Cushing Response during Infusion Study? Thanks to Dr.E.Schmidt

39 40 30 Δ ABPm 20 (mmhg) Δ ICP (mmhg) r=0,46 p=0.006 Figure 2 Thanks to Dr.E.Schmidt

40 Changes in ICP and other haemodynamic parameters Baseline Plateau Difference ICP (mmhg) 8.2 ± ± (+204.8%) < ABPm (mmhg) ± ± (+8.1%) < ABPs (mmhg) ± ± (+7.8%) < ABPd (mmhg) 76.5 ± ± (+18.3%) < ABPa (mmhg) 35.1 ± ± (+8.3%) 0,049 CPP (mmhg) 98.3 ± ± (-8.3%) < HR (min -1 ) 70.4 ± ± (-0.1%) 0,903 HRsd 3.11 ± ± (+44.8%) < HRcv ± ± (+46%) 0,0005 FVm (cm s -1 ) 55.6 ± ± (-8.2%) < FVs (cm s -1 ) 83.0 ± ± (-2.8%) 0,011 FVd (cm s -1 ) 37.9 ± ± (-12%) < PI ± ± (+14.3%) < Thanks to Dr.E.Schmidt

41 Message to take home: All parameters of CSF compensatory model may be estimated during infusion test CSF-CBF coupling phenomena were identified: autoregulation, vasogenic waves, etc. Not a single parameter but whole profile of recorded variables characterize disorder of CSF compensation: Rout>13; E>0.21; ICPbaseline>18 mm Hg; AMPpp>5 mm Hg; Slow waves >2 mm Hg; RAPbaseline>0.6; slope of AMPp line>0.2; presence of plateau wave during infusion. In NPH white matter CBF is depleted closer to ventricles.