The Effects of Twenty Degree Head-Up Tilt Upon the Cerebral Circulation of Patients With Arterial Hypertension Before and After Sympathectomy 1

Q: What does this research mean for the field?

A twenty-degree head-up tilt can be tolerated for 20 minutes by hypertensive patients as early as two weeks after a Smithwick sympathectomy, allowing for the measurement of cerebral circulation. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Joseph H. Hafkenschiel; Charles W. Crumpton; Henry A. Shenkin; John H. Moyer; Harold A. Zintel; Herbert Wendel; William A. Jeffers; Sally Conlin Harned; Nelly J. Keffer; Geraldine Croft

doi:10.1172/jci102494

August 1, 1951Journal of Clinical InvestigationOpen Access

The Effects of Twenty Degree Head-Up Tilt Upon the Cerebral Circulation of Patients With Arterial Hypertension Before and After Sympathectomy 1

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Why the study?

Does a 20-degree head-up tilt alter cerebral circulation, oxygen metabolism, and cerebrovascular resistance in patients with essential hypertension before and after sympathectomy?

Structured PICO

Does a 20-degree head-up tilt alter cerebral circulation, oxygen metabolism, and cerebrovascular resistance in patients with essential hypertension before and after sympathectomy?

P

Population

33 patients with essential hypertension (18 unoperated, 15 post-sympathectomy) selected from medical and surgical wards. Preoperatively all had moderate to marked hypertension with retinopathy grades II to IV, fluoroscopic and electrocardiographic evidences of left ventricular hypertrophy, and moderate impairment of renal function. No patient showed BUN >20 mgm. % or signs of congestive heart failure at the time of the study.

I

Intervention

20-degree head-up tilt for 20 minutes.

C

Comparator

Supine position (baseline control measurements) and comparison between unoperated essential hypertension patients and post-sympathectomy patients.

O

Outcome

Changes in cerebral blood flow, cerebral oxygen consumption, and 'effective' cerebral mean arterial pressure.surrogate

A 20-degree head-up tilt in hypertensive patients induces a drop in cerebral arterial pressure that is partially compensated by decreased cerebrovascular resistance, though unoperated patients may still experience symptoms of cerebral anoxia.

Limitations

Accurate control of the environmental temperature was not possible.
Venous oxygen content is a less adequate measure of cerebral oxygen homeostasis than venous oxygen saturation or tension.

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Implication

Preserved cerebral blood flow during tilt suggests intact autoregulation in hypertension; leaves open sympathectomy effects on resistance.

Abstract

The present study was undertaken in order to measure the effect of a slight elevation of the head and shoulders upon the, cerebral circulation of hypertensive patients following sympathectomy. Twenty degree tilt was chosen because it could be tolerated for 20 minutes, as early as two weeks after the Smithwick sympathectomy.

Discussion

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Cite This Study

Hafkenschiel et al. (1951) studied this question.

synapsesocial.com/papers/6a13e0c07753e742da598522 https://doi.org/10.1172/jci102494

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The Effects of Twenty Degree Head-Up Tilt Upon the Cerebral Circulation of Patients With Arterial Hypertension Before and After Sympathectomy 1

Structured PICO

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

The Effects of Twenty Degree Head-Up Tilt Upon the Cerebral Circulation of Patients With Arterial Hypertension Before and After Sympathectomy 1

Structured PICO

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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