19. Monitoring of CA using TCD- Mx and Sx

Transcription

1 19. Monitoring of CA using TCD- Mx and Sx

2 Drawing the autoregulatory curve: in clinical practice such dramatic changes in CPP are not permissible

3 Monitoring cerebral autoregulation - certainly not a new concept Diehl RR, Linden D, Lucke D, Berlit P: Spontaneous blood pressure oscillations and cerebral autoregulation. Clin Auton Res 8: 7-12, 1998 Hu HH, Kuo TB, Wong WJ, Luk YO, Chern CM, Hsu LC, Sheng WY: Transfer function analysis of cerebral hemodynamics in patients with carotid artery stenosis. J Cereb Blood Flow Metab 19: , 1999 Panerai RB, White RP, Markus HS, Evans DH. Grading of cerebral dynamic autoregulation from spontaneous fluctuations in arterial blood pressure. Stroke 29: , 1998 Steinmeier R, Bauhuf C, Hubner U, Bauer RD, Fahlbusch R, Laumer R, Bondar I: Slow rhythmic oscillations of blood pressure, intracranial pressure, microcirculation, and cerebral oxygenation. Dynamic interrelation and time course in humans. Stroke 27: , 1996 Zhang R, Zuckerman JH, Giller CA, Levine BD: Transfer function analysis of dynamic cerebral autoregulation in humans. Am J Physiol. 274: H233-H241, 1998

4 CEREBRAL AUTOREGULATION Testing * Clear stimulation: -drug to rise ABP -leg cuff release -head down tilt -lower body pressure -slow respiration -transient compression Monitoring *No stimulation; spontaneaous waves of ABP or CPP Better accuracy One-off measurement Worse accuracy (SNR worse) Information continuous in time may be time-averaged

5 Mx: an index of autoregulation CEREBRAL AUTOREGULATION IMPAIRED (Mx positive): CEREBRAL AUTOREGULATION INTACT (Mx<=0): Czosnyka M, Smielewski P, Kirkpatrick P, Menon DK, Pickard JD. Monitoring of cerebral autoregulation in head-injured patients. Stroke 27: , 1996

6 Mx is noisy ; it requires time-averaging. However it may explain changes in cerebral autoregulation which happen in time

7 Monitoring of transient phenomena: Positive Mx indicates loss of cerebral autoregulation at the top of plateau waves Czosnyka M, Smielewski P, Piechnik S, Schmidt EA, Al-Rawi P, Kirkpatrick PJ, Pickard JD: Hemodynamic characterization of intracranial pressure plateau waves in head-injured patients. J Neurosurgery 1999; 91:11-19.

8 CONTINUOUS MONITORING OF CA: TIME-RELATED CHANGES ABP ICP

9 Validation of Mx: Positive correlation with static rate of autoregulation (SROR) in 17 head injured patients Lang EW, Mehdorn HM, Dorsch NW, Czosnyka M. Continuous monitoring of cerebrovascular autoregulation: a validation study. J Neurol Neurosurg Psychiatry. 2002;72(5):

10 Validation : Transient Hyperaemic Response Test (Short [6-8 sec] compression of the CCA) THRT Positive Intact Autoregulation THRR = 1.45 THRT agrees with Mx in HI (N=47 patients) THRT Negative Impaired autoregulation THRR = 0.95 Smielewski P, Czosnyka M, Kirkpatrick P, Pickard JD. Evaluation of transient hyperaemic response test in head injured patients. J. Neurosurg 1997; 86:

11 FV=a*EtCO2+b*ABP

12 Relatively good correlation between phase shift, CO2 reactivity and correlation index in patients with carotid stenosis Reinhard M, Roth M, Muller T, Czosnyka M, Timmer J, Hetzel A. Cerebral autoregulation in carotid artery occlusive disease assessed from spontaneous blood pressure fluctuations by the correlation coefficient index.stroke Sep;34(9):

13 Agreement with Panerai s ARI (Anesth Analg Jan;106(1):234-9)

14

15 Autoregulation and arterial CO 2 Mx responds to PaCO 2 during routine CO 2 -reactivity testing.

16 Indices of autoregulation should be always CO2-corrected Mx : 0.2 per 1kPa of EtCO2 RoR: per 1kPa of EtCO2 Piechnik SK, Yang X, Czosnyka M, Smielewski P, Fletcher SH, Jones AL, Pickard JD: The continuous assessment of cerebrovascular reactivity: a validation of the method in healthy volunteers. Anesth Analg 89: 944-9, 1999

17 Study in volunteers: Mx well agreed with static rate of autoregulation (leg-cuff test, Aaslid et al, 1983) R 2 =0.66; N=14, 3 PaCO2 levels Piechnik SK, Yang X, Czosnyka M, Smielewski P, Fletcher SH, Jones AL, Pickard JD: The continuous assessment of cerebrovascular reactivity: a validation of the method in healthy volunteers. Anesth Analg 89: 944-9, 1999

18 MxA: calculated with MAP or Mx: calculated with CPP? Mxa is well correlated with Mx but discrepancies are possible Generally Mxa>Mx

19 Mx correlates with outcome better than Mxa (Lewis et al. Acta Neurochir (Wien). 2007;149(6):549-55)

20 F statistics values for different autoregulation indices Mx Sx Dx 5 0 GOS Favorable Survival Many thanks to Mr.K.Budohoski

21 Myth: Patients in different clinical conditions can be compared 1- head injury- survivors 2- head injury- died 3- carotid artery stenosisunilateral 4- carotid artery stenosisbilateral 5- volunteers (young)- normocapnia 6- volunteers (young)- hypercapnia 7- SAH patients- no spasm 8- SAH patients- spasm

22 APPLICATIONS: TBI Relationship between Mx and CPP replicates Lassen s curve in head injury- review of 188 cases Czosnyka M, Smielewski P, Piechnik S, Steiner LA, Pickard JD: Cerebral autoregulation following head injury. J Neurosurg 2001, 95 (5),

23 HEAD INJURY: AUTOREGULATION IS SIGNIFICANTLY WORSE IN PATIENTS WITH UNFAVOURABLE OUTCOME Czosnyka M, Smielewski P, Piechnik S, Steiner LA, Pickard JD: Cerebral autoregulation following head injury. J Neurosurg 2001, 95 (5),

24 Autoregulation is worse first two days following trauma but only in patients who died (red line)

25

26 AUTOREGULATION: SIDE-TO-SIDE DIFFERENCE (60 SEVERELY HEAD INJURED PATIENTS) Example (rare!) of impaired autoregulation on right side and preserved on left side. Schmidt EA, Czosnyka M, Seeley H, Smielewski P, Al-Rawi P, Raabe A, Matta BF, Kirkpatrick PJ, Pickard JD. Asymmetry of cerebral circulation following head injury. J Cerebral Blood Flow Metab 1999; 19:S364

27 SIDE-TO-SIDE DIFFERENCE IN AUTOREGULATION: VOLUNTEERS: HEAD INJURY: N=44; R=0.89 Patients who died Schmidt EA, Czosnyka M, Seeley H, Smielewski P, Al-Rawi P, Raabe A, Matta BF, Kirkpatrick PJ, Pickard JD. Asymmetry of cerebral circulation following head injury. J Cerebral Blood Flow Metab 1999; 19:S364

28 SIDE-TO-SIDE DIFFERENCE IS GREATER IN PATIENTS WITH MIDLINE SHIFT AND IN THOSE WHO DIED: Schmidt EA, Czosnyka M, Smielewski P, Piechnik SK, Pickard JD. Asymmetry of cerebral autoregulation following head injury. Acta Neurochir Suppl :

29 Left side expansion Right side expansion Shift from the Left Right R L R L to the Right Shift from the to the Left Worse autoregulation on the Left Worse autoregulation on the Right Figure 3 b Mxl Mxr >0 i.e. Mxl > Mxr Figure 3 a Mxl Mxr <0 i.e. Mxr > Mxl Thanks to Dr. E.Schmidt

30 Left-right difference in Mx Figure 3 a Midline shift (mm) r=-0.42 P=0.03 n=27 Thanks to Dr. E.Schmidt

31 SAH:

32 Karol Budohoski study Variable DCI group Non-DCI group p (n=32) (n=66) Age, y (±SD) 56±10 57± Sex female/male* 22/10 47/ WFNS grade, median , n , n , n , n , n Modified Fisher grade, median , n , n , n , n Aneurysm location AComA, n ACA, n MCA, n ICA, n AChA, n PComA, n PCA, n PICA, n BA, n VB, n Clipping/coiling, n * 23/11 44/ Re-bleeding, n Hydrocephalus, n EVD, n Vasospasm, n < Non-invasive ABP Total monitoring time per patient per 86±65 82± session, min±sd Total sessions per patient, median (range) 4 (2-11) 4 (2-7)

33 Yellow: Early disturbed autoregulation, Blue: normal autoregulation Dashed line indicates median onset time of macrovascular spasm

34 DCI Multivariate analysis B (SE) Wald p OR 95% CI for OR Age>55 y (0 68) Male sex (0 74) WFNS (0 27) Mod Fisher (0 74) Hydrocephalus 0 11 (0 85) EVD 0 21 (1 05) Sepsis 1 49 (0 9) Metabolic derangements (1 02) FV > 120 [cm/s]; LR > (0 79) Sxa 2 54 (0 74) TOxa 1 68 (0 74)

35 Asymmetry of CA- DCI & Outcome

36 Conclusions from prospective study Early impairments in cerebral autoregulation can predict DCI Similar accuracy of TCD- and NIRS-based autoregulation, but 100% specificity when all indices show impaired autoreg. Unilateral autoregulatory failure is related to DCI Bilateral autoregulatory failure is related to unfavourable outcome at 3 months.

37 Unilateral CCA stenosis Ipsilateral vs contralateral difference in cerebrovascular of reactivity are significant and dependant on level of stenosis

38 Normal Pressure Hydrocephalus Relationship between pressure autoregulation and CSF compensatory reserve in hydrocephalus (43 patients with NPH, infusion studies) In patients with normal CSF circulation there is an association with dysautoregulation that is not found in patients with increased resistance to CSF outflow. Does this indicate underlying cerebrovascular disease? Czosnyka ZH, Czosnyka M, Whitfield PC, Donovan T, Pickard JD. Cerebral autoregulation among patients with symptoms of hydrocephalus. Neurosurgery. 2002;50(3):526-32

39

40 Monitoring during liver transplant

41 Mx <LDx. Is cortex more vulnerable than rest of the brain?

42 Messages to take home: CA can be monitored continuously Methods: ARI, phase shift, Mx Impaired autoregulation predicts bad outcome in TBI In vasospasm autoregulation deteriorates In unilateral spasm, carotid artery stenotic disease, TBI with midline shift, unilaterarly impaired autoregulation indicates haemodynamically relevant asymmetry