Pressure reactivity: Relationship between ICP and arterial blood pressure (ABP). Pressure-reactivity index, computational methods. Clinical examples.

Transcription

1 Pressure reactivity: Relationship between ICP and arterial blood pressure (ABP). Pressure-reactivity index, computational methods. Clinical examples. Optimization of cerebral perfusion pressure: Relationship between Pressure Reactivity and CPP. Does optimal CPP exist always? Implications on management.

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3 Simultaneous analysis of slow changes in arterial pressure and ICP System with disturbed pressurereactivity Pressurereactivity works properly

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5 Thanks to Dr.P.Smielewski PRx- Calculation principles Input signals ICP, ABP Ouput trend PRx ABP 10 sec window 5 min window MAP Mean(ABP) Mean(ICP) MICP ICP Correlation(MAP, MICP) Primary analysis Final Analysis

6 PRx is a rather noisy parameter Some smoothing is required PRx Smoothed PRx Thanks to Dr.P.Smielewski

7 Intracranial Hypertension

8 Plateau Wave

9 Arterial Hypertension

10 CT Scan 1 Scan 2 SROR (CPP = 74 mmhg) (CPP = 98 mmhg) 5 60% % % 0.4 Figure 5: PET vs. PRx PRx r 2 = 0.32 p = 0.02 (n = 17) PRx correlates with PET-static rate of autoregulation Global SROR PET Steiner LA, Coles JP, Johnston AJ, Chatfield DA, Smielewski P, Fryer TD, Aigbirhio FI, Clark JC, Pickard JD, Menon DK, Czosnyka M. Assessment of Cerebrovascular Autoregulation in Head-Injured Patients. A Validation Study.Stroke :

11 rcbf CMRO 2 OEF 0-30 ml/100g/min m/100g/min 0-75 % r 2 = 0.34 p = r 2 = 0.61 p < PRx 0.2 PRx global CMRO 2 (ml 100g -1 min -1 ) Global oxygen extraction fraction (%)

12 FLUX ICP ABP PRx and the LLA ABP lowered to zero in piglet LDF vs. CPP to find lower limit of autoregulation PRx compared against LLA AUC=0.91!! Brady K, et al: Stroke 2008 Lee J, et al: Stroke 2009

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14 LOOK at two Periods 1: PRX ~-1 and 2: PRx~+1 1 2

15 Individual trends are most important

16 Monitoring of Pressure Reactivity Index ICM+ software:

17 Ups and downs... Final was not very optimistic

18 Deterioration of PRx precedes refractory intracranial hypertension?

19 Refractory intracranial hypertension (2) ABP mmhg ICP mmhg PRx CPP mmhg

20 Mortality rate dramatically depends on PRX

21 Optimal CPP- oriented therapy PRx PRx Mx Both PRx and Mx show the U-shape relationship with mean CPP (200 patients!). This indicate that for low CPP and CPP above 90 mm Hg both autoregulation and pressure reactivity are defective. There is an optimal CPP from 70 to 90 mm Hg which helps to restore vascular functions after head injury a.) a.) Optimal CPP Cerebral Perfusion Pressure (mm Hg) Cerebral Perfusion Pressure (mm Hg) Steiner LA at al. Continuous monitoring of cerebrovascular pressure reactivity allows determination of optimal cerebral perfusion pressure in patients with traumatic brain injury. Crit Care Med Apr;30(4):733-8.

22 New results Thanks to Dr. M.Aries

23 If we can see it in statistical evaluation of big series of patients, can we see it in individual cases? 4 6 hours moving window The chart shows that lowest PRx values corresponding to the strongest autoregulation level fall in the CPP range of mmhg Thanks to Dr. P.Smielewski

24 Optimal CPP in individual cases Thanks to Dr.L.Steiner

25 Optimal CPP oriented therapy? CPPopt ADMISSION TO CRITICAL CARE UNIT START TREATMENT AT CPP 70 MM HG (OR HIGHER IN SEVERLY HEAD INJURED PATIENTS) MONITOR AND AVERAGE PRx FOR 2 HOURS Patient 1 IDENTIFY RANGE OF MINIMAL PRx BY VARYING CPP IN STEPS OF 10 mm Hg OVER 2 HOUR PERIODS CPP OPT IDENTIFIED CALCULATE CPP OPT NO CPP OPT Hours MINIMIZE CPP CPP OPT DURING THE FOLLOWING 2 HOURS MONITOR AND MINIMIZE PRx, POOL DATA AFTER 2 HOURS Steiner LA, Czosnyka M, Piechnik SK, Smielewski P, Chatfield D, Menon DK, Pickard JD. Continuous monitoring of cerebrovascular pressure reactivity allows determination of optimal cerebral perfusion pressure in patients with traumatic brain injury. Crit Care Med Apr;30(4):733-8.

26 CPP OPT and Outcome r = (Spearman rank test) p = Thanks to Dr. L.Steiner

27 CAMBRIDGE PROJECT: M.ARIES et al, 2010 Method Retrospective analysis (single centre) Data base (n=327) TBI pts (GCS <8 in 80%) Continuous ICP/ABP monitoring (50 Hz) Glasgow outcome scale at 6 months Assumption: CPP optimal exists Narrow (one) CPP optimal range CPP optimal = the CPP at best cerebral vasoreactivity (pressure) autoregulation parameter: PRx - Correlation coefficient between ABP/ICP - CPP optimal= CPP at lowest PRx

28 Continuous assessment of CPPopt and real-time comparison with median CPP- 4 hours window

29 Optimal CPP as an individual threshold for CPP oriented therapy F value much greater than for set threshold

30 Rate of favourable outcome reaches maximum when CPP is close to optimal CPP For lower CPPs mortality increases For greater CPPs, rate of severe disability increases

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32 CONCEPT CPPopt vs. standard CPP based pressure management Frankfurt 6. Mai 2012 IGNITE Jennifer Diedler Martin Schuhmann

33 In a meanwhile we are still doing observational studies: Refractory intracranial hypertension- red line again

34 Matchining Prx-CPP curve; only a left branch!

35 Road/work ahead.. (2) Large pooled TBI database Does the relation with outcome hold? Specific TBI pts benefit Edema/contusions DAI Target or Direction? Visual display of PRx/CPPopt (poster.) Thanks to Marcel Aries and Ari Ercole

36 Prx SAH: Effect of Vasospasm SAH CPP [mmhg] Thanks to Dr. P.Biljenga

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38 What do we know so far about PRx in SAH? (statin trial, placebo branch). PRx agrees with Transient Hyperaemic Response Test and gets worse in vasospasm Tseng MY, Czosnyka M, Richards H, Pickard JD, Kirkpatrick PJ. Effects of acute treatment with pravastatin on cerebral vasospasm, autoregulation, and delayed ischemic deficits after aneurysmal subarachnoid hemorrhage: a phase II randomized placebo-controlled trial. Stroke Aug;36(8):

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40 Summary Simple analysis of ABP-ICP interaction (low bandwidth) Positive association with outcome Detection of optimal CPP Good agreement with other more expensive methods Promising value of PRx after SAH