Optimal cerebral perfusion pressure in traumatic brain injury patients.

Weersink, C. (Corien) (2013) Optimal cerebral perfusion pressure in traumatic brain injury patients. thesis, Medicine.

Text WeersinkC.pdf Restricted to Registered users only Download (1MB)

Abstract

Background: In the management of patients with severe traumatic brain injury (TBI) it is important to maintain an adequate cerebral perfusion pressure (CPP). A potential target of ‘optimal’ cerebral perfusion pressure (CPPopt) can be calculated continuously and automatically at the bedside using the cerebrovascular pressure reactivity index (PRx). Plotting averaged PRx against CPP bins over a 4-hour window frequently produces a U-shaped curve, with the lowest point on the curve (minimum PRx) corresponding to the CPPopt. Retrospectively it was possible to produce a CPPopt curve only in 55% of total monitoring time.(1) The aim of this pilot study in severe TBI patients was to investigate the relation between absence of a CPPopt curve and physiological variables, autoregulation state, clinical factors and interventions. Material and Methods: This prospective observational study was performed on neuro critical care units in two university centres. All patients had continuous monitoring of arterial blood pressure (ABP), intracranial pressure (ICP) and CPP (CPP = ABP – ICP), with real time calculations of PRx using brain monitoring software (developed in Cambridge). Clinical events were inserted on a daily basis, including changes in physiological variables, sedative drugs, vasoactive drugs and specific therapy (surgical and non-surgical) for intracranial hypertension (ICH). The collected data was divided into 4-hour periods with the primary outcome being absence of a CPPopt curve. For every period mean values (± standard deviations) of ABP, ICP, PRx and other physiological variables were calculated; clinical events were organised using predefined scales. A stepwise logistic regression analysis was performed to ascertain the independent effects of the predefined variables on the absence of a CPPopt curve. Results: A total of 17 TBI patients, median Glasgow Coma Score 7 (range 3-11), were monitored between May 2012 and May 2013 together with real time annotation of clinical events. In total 739 4-hour periods, median 33 (IQR 44) per patient, were analysed. In 23% of the periods a CPPopt curve was absent. The backward stepwise logistic regression analysis produced a model of CPPopt absence with highly statistically significant fit, χ2 = 129.164, p < .0005. Of the 14 predictor variables 6 had an independent effect on the curve absence. Absence of slow ABP waves, absence of slow ICP waves, a longer period after trauma, not using paralytic medication, not applying bolus therapy for ICH and high vasoactive dose were all independently associated with absence of the CPPopt curve. Conclusions: This pilot study identified 6 factors that were independently correlated with absence of the cerebrovascular pressure reactivity curve (CPPopt curve). The findings seem to emphasize the importance of sufficient amplitude of slow waves (in ABP and ICP) and the influence of clinical events on the clinical application of this promising method. In order for the CPPopt methodology to be ready for patient management, these interactions have to be better understood.

Item Type:	Thesis (Thesis)
Supervisor name:	Dijk, dr. J.M.C. van and Aries, dr. M.J.H. and Horst, dr. G.J. ter
Supervisor name:	Smielewski, dr. P.
Faculty:	Medical Sciences
Date Deposited:	25 Jun 2020 10:55
Last Modified:	25 Jun 2020 10:55
URI:	https://umcg.studenttheses.ub.rug.nl/id/eprint/1583

Actions (login required)

View Item