Vol. 80 – No. 1 MINERV A ANESTESIOLOGICA 113B R I E F R E P O R TAnno: 2014 [629463]

Vol. 80 – No. 1 MINERV A ANESTESIOLOGICA 113B R I E F R E P O R TAnno: 2014
Mese: JanuaryVolume: 80No: 1Rivista: MINERV A ANESTESIOLOGICACod Rivista: Minerva AnestesiolLavoro: titolo breve: Decompressive craniectomy
primo autore: FRISARDI
pagine: 113-8
A factor limiting organ donation in Italy is the
availability of suitable brain-death (BD) or-
gan donors. Italian legislation defines the diag-nostic procedures for determining BD (Law no. 578 dated 29/12/1993 and Ministerial Decree no. 582 dated 22-Aug-1994 recently updated by Ministerial Decree dated 11/04/2008): after ini-tial documentation of the clinical signs of BD, repetition of clinical testing and confirmation of the loss of bioelectrical activity of the brain is required. However, some cases need demonstra-tion of cerebral circulatory arrest (CCA) such as
children under one year and clinical situations which do not allow a definite etiopathogenetic diagnosis or are likely to interfere with the over-all clinical-instrumental findings, including the presence of CNS depressants, facial or head trauma or recent surgery which may prevent re-cording of brain electrical activity or testing of brain stem reflexes.
According to Italian legislation each hos-
pital can choose the method to confirm CCA depending on technical instrumentation and personnel skills available. The National Ad-Decompressive craniectomy may cause
diagnostic challenges to asses brain death by
computed tomography angiography
F. FRISARDI 2, M. STEFANINI 1, S. NATOLI 2, 3, V. CAMA 1, G. LORENI 1
F. DI GIULIANO 1, D. FIUME 2, 3, C. LEONARDIS 2, 3, M. DAURI 2, 3
A. F. SABATO 2, 3, G. SIMONETTI 1, F. LEONARDIS 2, 3
1Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiation Therapy, Tor
Vergata University of Rome, Rome, Italy; 2 Department of Emergency, Critical Care Medicine, Pain Medicine and
Anesthesiology, Intensive Care Unit, Tor Vergata Fondazione Policlinico, Rome, Italy;3 Department of Clinical Science
and Translational Medicine, Tor Vergata University of Rome, Rome, Italy
A B S T R A C T
According to Italian legislation to diagnose brain death (BD) after the initial documentation of the clinical signs,
repetition of clinical testing and confirmation of the loss of bioelectrical activity of the brain (EEG) is required. However, when EEG is unreliable it is necessary to demonstrate cerebral circulatory arrest (CCA). Accepted imaging techniques to demonstrate CCA include: cerebral angiography, cerebral scintigraphy, transcranial Doppler (TCD) and computed tomography angiography (CTA). This latter technique, due to its large availability, low invasivity and easy and fast acquisition is widely used over the country.
Nevertheless its diagnostic reliability is affected by
some limitations in patients with decompressive craniectomy. Here we report two cases of brain injury with clinical signs of BD and at the same time, opacification of intracranial arteries on CTA and a pattern consistent with flow arrest on the corresponding insonable arteries on TCD. The discrepancy between CTA and TCD results points out a methodology limitation that could be overcome by updating Italian legislation according to other European Countries legislation. (Minerva Anestesiol 2014;80:113-8)
Key words:
B
rain death – Tomography, X-ray computed – Ultrasonography, Doppler, transcranial.
Comment in p. 8.
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FRISARDI DEC OMPRESSIVE CR ANIECTOM y
114 MINERV A ANESTESIOLOGICA Januar y 2014visory Committee on Organ T ransplantation
(NACOT) recently drafted guidelines for the application of instrumental cerebral blood flow (CBF) evaluation, updated to 20/02/2009. Ac-cepted imaging techniques for the measurement of CBF include: cerebral angiography, cerebral scintigraphy, transcranial Doppler (TCD) and CT angiography (CTA).
1-6 This latter tech-
nique, due to its large availability, low invasiv-ity and easy and fast acquisition is widely used over the country.
5-6 Nevertheless its diagnostic
reliability is affected by some limitations. Here we report two cases of brain injury with clinical signs of BD and at the same time, opacification of intracranial arteries on CTA and a pattern consistent with flow arrest on the corresponding insonable arteries on TCD.
Case series
Case 1.— A 38 year old patient was admitted to our
emergency department after a motorcycle accident. On
arrival he was on cardiac arrest. An advanced cardiac life support was immediately performed until return of sponta-neous circulation (ROSC) after 10 minutes of chest com-pressions. On stabilization of vital signs, the GCS was 3. An urgent CT scan detected a large subdural hematoma within the left hemisphere causing midline shift and compression over homolateral ventricular system. In association there were basilar skull and cervical vertebre fractures. A consult-ant neurosurgeon decided for an emergency decompressive craniectomy and evacuation of the subdural hematoma. Thereafter he was transferred to our ICU for specific moni-toring and management. On admission he was uncon-scious, without reaction to painful stimuli. Pupils were 1mm and did not respond to light. Corneal reflexes were absent. Spontaneous respiration was insufficient so artificial ventilation was continued. He was treated according to the local protocol for the treatment of acute brain injury aiming at maintaining adequate cerebral perfusion. The CBF was monitored daily with TCD (Multi-Dop® Digital, Compu-medics DWL, Germany). On day five the clinical examina-tion fulfilled the criteria for BD but according to the con-sultant neurophysiologist a complete electrode coverage for EEG was not accessible due to the recent craniectomy.
The TCD conducted using both temporal acoustic
windows revealed intracranial bilateral blood flow through the middle cerebral artery (MCA) and the anterior cer-ebral artery (ACA), with left prevalence. Since insonation of the subtentorial arteries was difficult for the risk of dis-location of cervical fractures, a TCA was asked. This exam was carried out by a 64-slice volumetric CT Scanner (GE Fairfield, CT – USA) and demonstrated CBF through the main intracranial arteries despite a threadlike opacifica-tion of the basilar artery (BA) (Figure 1A).The day after a new TCD showed bidirectional flow
at both MCAs level, systolic spikes at the left ACA level,
impossibility to insonate the right ACA. According to the NACOT guidelines, these criteria suggest flow arrest. Nevertheless an evaluation of distal vertebral arteries and BA is needed. A new CTA showed internal carotid artery (ICA) and MCA opacification on the side of craniecto-my. On the opposite side the absence of filling from the petrous portion of the ICA was shown (Figure 1B).
Case 2.— A 36 year old man was admitted after a car
accident. On arrival the patient was unconscious, unable to react to any stimulus, his pupils were non reactive. He was spontaneously breathing, SpO2 was 98% on oxygen but his blood gas analysis revealed acidosis. After intubation and hemodynamic stabilization a CT scan showed a left occipi-tal skull fracture with an epidural left temporal hemorrhage associated with intraparenchymal petechial hemorrhage.
The patient underwent an emergency fronto-temporo-
parietal craniectomy and evacuation of the hematoma. Intraoperative findings showed a linear skull fracture ex-tending across a venous sinus causing extensive bleeding.
He was transferred to our ICU without any change in
neurological assessment. He maintained mechanical venti-lation but spontaneous breathing was present. He was treat-ed according to the same local protocol applied before and CBF was monitored daily with TCD. After 7 days he de-veloped the clinical criteria for BD . As before, the EEG was
technically unfeasible due to the recent surgery. The TCD showed bilateral bidirectional flow reversing on MCAs and systolic spikes at the posterior cerebral arteries level.
Again, the insonation of subtentorial arteries was haz-
ardous for the presence of cervical fractures. The CTA showed bilateral opacification of the petrous portion of ICAs (Figure 2).
In both patients cardiac death occurred few days after.
During this period, they never fulfilled the CTA criteria to diagnose CCA.
Results
The ancillary tests here described were per-
formed according to Italian legislation and NA-
COT guidelines. Nevertheless their results were discrepant. Namely, bidirectional flow in TCD was confirmatory of flow arrest on insonable arteries whereas the CTA revealed opacification of corresponding intracranial arteries. We could not diagnose BD in these two potential organ donors.
Discussion
BD in Italy is defined as “the irreversible loss
of all the functions of the brain”. CBF measure-ments are necessary in some particular cases de-
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DECOMPRESSIVE CR ANIECTOM y FR ISARDI
Vol. 80 – No. 1 MINERV
A ANESTESIOLOGICA 115With its rate of 21.9 organ donors PMP , Italy
is the third country within the European Un-
ion regarding organ donation, after Spain (29.2) and France (22.8).
7 However the rate of organ
donation can increase: according to the Italian National Institute of Statistics, deaths from road accidents in 2010 in Italy have been 4,090. The mean age of deaths for males was 20-24 years, but high rates of deaths were also registered within 25 to 29 and 30 to 34.
8 Some consid-fined in Law no. 578 dated 29/12/1993.1 The
D.M. 582/94 and to the NACOT guidelines define very strictly methods and times for the correct execution of CTA leading to more ac-curate standardization and leaving less space to subjectivity in the interpretation of the exam. Nevertheless, when intracranial pressure is low-ered by craniectomy, opacification of intracrani-al arteries on CTA may occur despite circulation is affected.Figure 1.—A, B) T ranscranial Doppler (TCD) and CT-Angiography (CTA) in Patient 1 with left decompressive craniectomy. A)
Both T ranscranial Doppler (TCD) and CT-Angiography (CTA) showed intra-cerebral blood flow; B) TCD showed bidirectional flow on left MCA level; CTA performed 4 hours later showed internal carotid artery (ICA) and MCA opacification on the side of craniectomy (left). On the right side the exam detected the absence of filling of the intracranial arteries.
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FRISARDI DEC OMPRESSIVE CR ANIECTOM y
116 MINERV A ANESTESIOLOGICA Januar y 2014present, can interfere with minimum technical
standards to perform EEG causing its unreli-ability or unfeasibility. This is one of the cases contemplated by Italian law, in which the evalu-ation of cerebral blood flow is mandatory. As CTA is emerging as the alternative to conven-tional angiography, its diagnostic limitations in patients with decompressive craniectomy may be an important limiting factor for organ pro-curement in our country.
The main factor limiting organ donation in
Italy is the lack of family consent, whereas pre-erations may derive from these numbers: first, the population considered is quite young, be-ing then ideal potential organ donors. Second, in our experience, patients involved in road ac-cidents are more likely to present to the emer-gency department with cerebral mass lesions needing emergency surgery. Emergency evacua-tion of a mass lesion is generally combined with decompressive craniectomy to favour brain per-fusion. Despite the craniectomy by itself is not a factor affecting the reliability of EEG, a large recent craniectomy, mostly if brain swelling is
Figure 2.—A-C) T ranscranial Doppler (TCD) and CT-Angiography (CTA) in Patient 2 with left decompressive craniectomy. A,
B) TCD showed bidirectional flow on both right (A) and left (B) MCAs; C) CTA performed few hours later showed bilateral opacification of MCAs.
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DECOMPRESSIVE CR ANIECTOM y FR ISARDI
Vol. 80 – No. 1 MINERV
A ANESTESIOLOGICA 117In our cases, the cerebral arteries that opaci-
fied on CTA, evaluated by TCD showed a pat-
tern consistent with absence of flow. On the con-trary, there are reports of false-negative results in cases of skull defects using TCD to detect CCA in brain death with flat EEG.
14 In addition, the
need for confirmatory testing has been ques-tioned by some authors who claim that no test can provide documentation of a loss of all neu-ronal functions for the definition of brain death, therefore confirmatory tests are useless.
15 In Eu-
rope there is fairly uniform agreement regarding the criteria for the clinical evaluation of brain death, although there is considerable variation in the use of additional confirmatory tests ac-cepted by law and in their interpretative criteria.
We believe that caution is needed in this im-
portant matter, and that the law should guar-antee for life as indeed the Italian law does. However, improvement is always possible: if the mere filling of intracranial arteries does not indi-cate the adequacy of perfusion, the study of the venous phase could improve the sensitivity of CTA leaving no room for individual interpreta-tion, which could cause serious ethical concerns.
The discrepancy between CTA and TCD re-
sults in our cases points out a methodology limi-tation that could be overcome both, by updating Italian legislation according to other European Countries legislation such as French or Spanish, or by performing ancillary tests evaluating cer-ebral perfusion rather than cerebral flow. Italian law accepts cerebral scintigraphy to evaluate cer-ebral perfusion. The main limitations of its use are the scarce availability, the longer duration of the exam and the associated risk and difficulty of transporting the unstable BD patient to the nu-clear medicine suite. CTA is preferred because of its accessibility, simplicity, widespread use, ease of interpretation and reproducibility.
9,11
Conclusions
Acknowledging the existing limitations in
this field, we are still far from the perfect tool to assess complete neuronal death. Nevertheless, further research validating current or evolving techniques of brain blood flow imaging can im-prove their diagnostic sensitivity and specificity.conceived attitudes about this issue can inter-fere with the final decision and socio-economic and socio-demographic variables (patient’s age, cause of death, race) and religious belief play a significant role. Educational efforts should be increased to overcome these limitations, howev-er the results may require a long period of time to be measurable. An upgrade of the current in-terpretative guidelines for BD diagnosis can give faster results, although less significant.
We are not the first to report that decom-
pressive craniectomy may affect the diagnosis of BD with CTA. Berenguer et al. noted that
decompressed patients with a clinical BD and absence of brain perfusion demonstrated with nuclear medicine perfusion test, showed mini-mal flow on CTA.
9 Dupas et al. in 1998 defined
the criteria for BD diagnosis with spiral CT. They noted that in BD the pericallosal and ter-minal arteries of the cortex, the internal cerebral veins, the great cerebral vein and the straight si-nus did not opacify on spiral CT.
10 Since then,
several studies permitted French legislation to define the actual criteria for BD confirmation by CTA based on the lack of opacification of 7 intracerebral vessels. On these basis Frampas et
al. constructed a 4-point CTA score based on
the lack of opacification of 4 cerebral vessels on the CT scan acquired starting 60 seconds after the contrast medium injection commenced.
11 In
the specific case of decompressive craniectomy, the French Society of Neuroradiology recom-mends that, if arterial opacification occurs, the deep venous network should be evaluated and BD can be confirmed in the absence of opacifca-tion of the left and right internal cerebral veins and of the great cerebral vein. In Spain, CTA is accepted as confirmatory test for diagnosing brain death. Again, the study of the venous flow is required, although Spanish guidelines do not enter in the specific case of decompressive crani-otomy.
12, 13
We did not perform the evaluation of venous
drainage as acquisition starting 20 seconds after the contrast medium injection is recommended by Italian guidelines for the diagnosis of CCA by CTA. Nevertheless, the only evaluation of artery phase can be misleading, showing “opaci-fication” which may not mean “circulation”.
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