Dataset Information

Intracranial pressure responsiveness to positive end-expiratory pressure is influenced by chest wall elastance: a physiological study in patients with aneurysmal subarachnoid hemorrhage.

ABSTRACT:

Background

Respiratory system elastance (E_RS) is an important determinant of the responsiveness of intracranial pressure (ICP) to positive end-expiratory pressure (PEEP). However, lung elastance (E_L) and chest wall elastance (E_CW) were not differentiated in previous studies. We tested the hypothesis that patients with high E_CW or a high E_CW/E_RS ratio have greater ICP responsiveness to PEEP.

Methods

An esophageal balloon catheter was placed to measure esophageal pressure. PEEP was increased from 5 to 15 cmH₂O. Airway pressure and esophageal pressure were measured and E_L, E_CW and E_RS were calculated at the two PEEP levels. Patients were classified into either an ICP responder group or a non-responder group based on whether the change of ICP after PEEP adjustment was greater than or less than the median of the overall study population.

Results

The magnitude of the increase in esophageal pressure (median [interquartile range]) at end-expiratory occlusion was significantly increased in the responder group compared with that in the non-responder group (4.1 [2.7-4.1] versus 2.7 [0.0-2.7] cmH₂O, p = 0.033) after PEEP adjustment. E_CW and the E_CW/E_RS ratio were significantly higher in ICP responders than in non-responders at both low PEEP (p = 0.021 and 0.017) and high PEEP (p = 0.011 and 0.025) levels. No significant differences in E_RS and E_L were noted between the two groups at both PEEP levels.

Conclusions

Patients with greater ICP responsiveness to increased PEEP exhibit higher E_CW and a higher E_CW/E_RS ratio, suggesting the importance of ECW monitoring.

SUBMITTER: Chen H

PROVIDER: S-EPMC6108121 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

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Publications

Intracranial pressure responsiveness to positive end-expiratory pressure is influenced by chest wall elastance: a physiological study in patients with aneurysmal subarachnoid hemorrhage.

Chen Han H Chen Kai K Xu Jing-Qing JQ Zhang Ying-Rui YR Yu Rong-Guo RG Zhou Jian-Xin JX

BMC neurology 20180824 1

<h4>Background</h4>Respiratory system elastance (E<sub>RS</sub>) is an important determinant of the responsiveness of intracranial pressure (ICP) to positive end-expiratory pressure (PEEP). However, lung elastance (E<sub>L</sub>) and chest wall elastance (E<sub>CW</sub>) were not differentiated in previous studies. We tested the hypothesis that patients with high E<sub>CW</sub> or a high E<sub>CW</sub>/E<sub>RS</sub> ratio have greater ICP responsiveness to PEEP.<h4>Methods</h4>An esophageal bal ...[more]

PMID: 30143022

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Project description:IntroductionObservational studies suggest that different classes of antihypertensive drugs may have different effects on the occurrence of intracranial aneurysms (IA) and subarachnoid hemorrhage (SAH). However, the reported results in previous studies are inconsistent, and randomized data are absent. We performed a two-sample Mendelian randomization (MR) analysis to study the causal effects of genetically determined blood pressure (BP) and genetic proxies for antihypertensive drug classes on the risk of IA and SAH.Materials and methodsGenetic instruments and outcome data were obtained from independent genome-wide association studies (GWAS) or published data, which were exclusively restricted to European ancestry. Causal relationships were identified using inverse-variance weighted MR analyses and a series of statistical sensitivity analyses. The FinnGen consortium was used for repeated analysis to verify results obtained from the above GWAS.ResultsTwo-sample MR analysis showed that genetically determined Systolic BP, Dystolic BP, and Pulse Pressure were related to a higher risk of IA and SAH. Based on identified single nucleotide polymorphisms (SNPs) that influence the effect of calcium channel blockers (CCB, 42 SNPs), beta-blockers (BB, 8 SNPs), angiotensin-converting enzyme inhibitors (ACEI, 2 SNPs), angiotensin receptor blockers (ARB, 1 SNPs), and thiazides (5 SNPs), genetically determined effect of CCBs was associated with a higher risk of IA (OR, 1.07 [95% CI, 1.03-1.10], p = 5.02 × 10-5) and SAH (OR, 1.06 [95% CI, 1.03-1.09], p = 1.84 × 10-3). No associations were found between other antihypertensive drugs and the risk of IA or SAH. The effect of CCBs on SAH was confirmed in FinnGenconsortium samples (OR, 1.04 [95% CI, 1.00-1.08], p = 0.042).Discussion and conclusionThis MR analysis supports the role of elevated blood pressure in the occurrence of intracranial aneurysms and subarachnoid hemorrhage. However, genetic proxies for calcium channel blockers were associated with an increased risk of intracranial aneurysms and subarachnoid hemorrhage. Further studies are required to confirm these findings and investigate the underlying mechanisms.

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Dataset Information

Intracranial pressure responsiveness to positive end-expiratory pressure is influenced by chest wall elastance: a physiological study in patients with aneurysmal subarachnoid hemorrhage.

Background

Methods

Results

Conclusions

Publications

Intracranial pressure responsiveness to positive end-expiratory pressure is influenced by chest wall elastance: a physiological study in patients with aneurysmal subarachnoid hemorrhage.

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