ICPモニタリングの意義

慈恵ICU勉強会

目次

なぜICPをモニターするのか

ICPモニタリングは予後改善に役立つか

ICPに替わるモニタリングはあるのか

ICPモニタリングの意義

頭部CT異常のある重症頭部外傷の50%以上にICP上昇あり

重症頭部外傷でICP>20mmHg は死亡率と強い相関あり

J. Neurotrauma 2007; 24(Suppl 1): S37-S44

経時的にICPが上昇してくるlarge MCA infarctionでは予後が悪い

ICP monitoring of large hemispheric infarction can predict clinical outcome. Pharmacologic intervention had no sustained effect. ICP monitoring was not helpful in guiding long-term treatment of increased ICP.

49 Pts Prospective study MCA large infarction Ipsilateral or bilateral ICP monitoring

ICP guided therapy (>25mmHg)

Aneurysmal SAHのガイドラインには、ICPに関する記載なし

ICHのガイドラインでは血圧管理でICPについて言及

Because of limited data regarding ICP in ICH, management principles for elevated ICP are borrowed from TBI guidelines.

No evidence indicates that hyperventilation, corticosteroids in conventional or large doses, furo-semide, mannitol, or glycerol or other measures that reduce intracranial pressure improve outcome in patients with ischemic brain.

A. Ischemic Brain Swelling

Acute Ischemic Strokeのガイドラインでは…

ICPを指標に用いる記載はない

2012.6.12現在 最新のガイドライン

Level I the strongest evidence for effectiveness, and represent principles of patient management that reflect a high degree of clinical certainty

Level II a moderate degree of clinical certainty.

Level III the degree of clinical certainty is not established

Guidelines for the Management of Severe Traumatic Brain Injury 3rd Editionより

GCS 3-8点 かつ 頭部CT異常 （血腫、挫傷、腫脹、ヘルニア、脳底槽の圧迫） があるすべての救命可能な患者で ICPをモニターすることをすすめる

頭部CT所見が正常な重症頭部外傷では 入院時に以下の2つ以上の要件を満たす場合に ICPモニタリングが検討される ・年齢> 40 ・片側または両側の運動麻痺 ・sBP<90mmHg

強い推奨のある標準治療なし

Guidelines for the Management of Severe Traumatic Brain Injury 3rd Editionより

Medline search ~ April 2006

強い推奨はない

ICP >20mmHgで治療介入を 開始することをすすめる

ICP値、臨床所見、頭部CT所見を 組み合わせて治療の要否を決定するのが よいかもしれない

目次

なぜICPをモニターするのか

ICPモニタリングは予後改善に役立つか

ICPに替わるモニタリングはあるのか

ICPモニタリングの意義

Meta-analysis of trials and case series “Aggressive treatment” is associated with a mean 12% decrease in the mortality rate and a 6% increase in favorable outcomes

ICPモニターを含む集中治療が重症頭部外傷の予後を改善する可能性がある。

Retrospective Cohort Study 1994-2001 Level I or II trauma center Blunt mechanism Age ≥20 to ≤50 years Admission to ICUs for at least 3days Met the BTF criteria (GCS≤8 @ED, CT demonstrating a TBI)

ICPモニタリングをしていたことが独立した予後規定因子だった。（特にhead-AIS≥4）

• CENTRAL,MEDLINE,EMBASE,CINAHL,SCI-EXPANDED,CPCI-S

• All RCTs • ICP vs no ICP • Primary Outcome measures: all-cause

mortality and severe disability at the end of the follow-up period

• No studies meeting the selection criteria have been identified.

In a randomized controlled trial in 3 trauma centers in Bolivia, test the effect on outcomes of management of severe TBI guided by information from ICP monitors vs. a standard empiric protocol.

Ongoing…??

目次

なぜICPをモニターするのか

ICPモニタリングは予後改善に役立つか

ICPに替わるモニタリングはあるのか

ICPモニタリングの意義

Miller‘s Anesthesia, 7th edition Chapter 94 Neurocritical Careより

TCD ONSD

Pathways in monitoring cerebral ischemia

• Indirect methods of assessing global and regional cerebral perfusion (ICP/CPP, transcranial Doppler)

• Assessment of adequacy of CBF at tissue level by monitoring global or regional oxygenation and metabolism (SjvO2, rSO2, PbtO2, microdialysis)

PRx: MAPの変動に対するCPP(ICP)の変動 ＝脳血管のautoregulationの破綻

CPPopt median: 70-75mmHg (ranged from 60-65mmHg to 95-100mmHg)

組織の酸素化はMAPの変動に対するICPの変動が最も少なくなるCPPでplateauに達する。

個人差あり。

TCD

• Noninvasive technique • Mean CBF velocity in the large intracranial arteries at

the level of the circle of Willis. • Lindegaard ratio = (flow velocity of the MCA)÷ (velocity measured in

the extracranial ICA) <3 implies hyperaemia >3 is likely to imply vasospasm

• Pulsatility Index: cerebral vascular resistance = (peak systolic velocity-end diastolic velocity)÷mean

velocity

81 Pts with SAH, closed head injury, other neurosurgical disorders A significant correlation (p< 0.0001) was found between the ICP and PI with a correlation coefficient of 0.938.

ICPとPIは相関がよさそうなので、ICP値の代用になるかもしれない が、連続モニタリングはできない。

Jugular venous oxygen saturation SjvO2

• A measure of global balance between cerebral oxygen delivery and utilization

• The normal range is 60–75%, and desaturation to less than 50% is regarded as indicative of cerebral ischemia.

• Decreases when there is disproportionately high metabolism compared to CBF (e.g. seizure or hyperthermia)

SjvO2は局所の酸素化の変化を反映しない。

SjvO2 does not decrease to below 50% until 13% of the brain becomes ischemic.

Outcomes were significantly worse in patiens who developed decreses in SjO2 to levels below 45% than in those whose SjO2 remained at or above 45%.

SjO2が低下した患者は予後が悪い。

Near-infrared spectroscopy NIRS

• A light beam in the near-infrared red range (700– 1000 nm) is passed through brain tissue, it is both scattered and absorbed.

• Changes in the concentration of near-infrared light as it passes through brain tissues can be quantified using a modified Beer-Lambert law.

An NIRS-based index called total hemoglobin reactivity (THx), was correlated with pressure reactivity index (PRx) derived from ICP and blood pressure waveforms.

40 Pts, Closed head injury Prospective? cohort

ICPを入れられない時にはNIRSが代用できるかもしれない…

Brain tissue oxygenation PbtO2

• A highly focal measure of cerebral oxygenation

• PbtO2 value in patients with normal ICP and CPP is 25– 30mmHg

• Critical threshold for ischemic damage is around 10–15 mmHg.

139 Pts ISS ≥16 and TBI PbtO2 guided therapy to maintain a brain oxygen level >20mmHg and ICP <20mmHg Compared with ICP/CPP-directed therapy (historical cohort)

PbtO2とICPを指標に重症頭部外傷を治療すると、 ICP/CPPを指標をするよりも死亡率が下がり、6ヶ月後の臨床予後が改善するかもしれない。

629 patients of severe TBI, cohort study ICP only vs ICP+PbtO2 PbtO2 monitoring did not reduce mortality, associated with poorer neurological outcome, increased hospital resource utilization.

PbO2モニタリングをICPに加える有用性は 複数の研究で相反する結果になっている

Cerebral microdialysis

• Biochemical changes occur before low CPP is detectable.

• The key substances that can be analyzed from the dialysate are: glucose, lactate, pyruvate, adenosine, xanthine, glutamate, aspartate, gamma amino butyric acid, glycerol, potassium, cytokines and administered drugs (e.g. antibiotics, temazolamide).

90 Pts Retrospective cohort MD catheters, ICP monitoring, arterial catherters

MDはICP/CPPと相関なく、予後とも相関がない。

223 Pts Prospective cohort

Metabolic markers は独立した予後予測因子 治療によるmarkerの改善が予後を改善するかは不明

Optic Nerve Sheath Diameter

• ICP elevation is transmitted through subarachnoid space, especially the retrobulber segment

• ONSD >5mm to detect ICP >20mmHg

• Noninvasive technique

• Simple and reproducible

Ultrasonography of ONSD showed good accuracy for detection of intracranial hypertension comparison with ICP devices

感度90%でICP上昇を診断できる＝10%はICP上昇を見逃す。

ICPモニタリングの意義

外傷性脳損傷で、予後不良につながる脳の循環不全を診断する

ICPを指標として治療したら予後が改善されるかどうかはわからない（RCTはない）

その他のモニタリング手法はICPとの比較はなく、観察研究のみ

→「脳循環のモニタリング自体に予後を改善する意味があるかどうか」が示されていない。

その他のモニタリングとの併用で有用である可能性はある。 まだまだ捨てたもんじゃない。

Further research…

ICP Monitoring Devices

Method Advantages Disadvantages

Intraventricular catheter Gold standard Insertion may be difficult

Measures global pressure Most invasive method

Allows therapeutic drainage of

CSF Risk of hematoma

In vivo calibration possible Risk of ventriculitis

Microtransducer sensor Robust technology Small zero drift over time

Intraparenchymal/ subdural

placement No in vivo calibration

Low procedure complication

rate Measures local pressure

Low infection risk

Epidural catheter Easy to insert Limited accuracy

No penetration of dura Rarely used

Low infection rate

Lumbar CSF pressure Extracranial procedure Does not reflect ICP

Dangerous if ICP elevated

O’Neill BR et al. A survey of ventriculostomy and intracranial pressure monitor placement practices. Surg Neurol 2008; 70:268-273 より改変

Meta-analysis of 23 studies A cumulative rate of positive CSF cultures of 8.8% per patient or 8.1% per EVD