Biomaterial Database

Intracranial responses to PEEP. 1976

S J Aidinis, and J Lafferty, and H M Shapiro

Elevated intrathoracic pressure due to positive end-expiratory pressure (PEEP) has the potential for increasing intracranial pressure (ICP) and reducing arterial blood pressure (BP). Such changes could critically reduce cerebral perfusion pressure (CPP = BP - ICP), This possibility was investigated in 15 cats with artificially-produced expanding intracranial masses (intracranial balloon). The interrelationships among ICP and central venous and arterial pressures were observed during application and removal of graded levels of PEEP (5, 10, 15 cm H2O). The electroencephalogram and pupillary diameters were monitored. At various levels of ICP, nine of the cats were given oleic acid intravenously to embolize the lung and cause pulmonary dysfunction. In cats not given oleic acid, PEEP caused a maximal reduction in cerebral perfusion pressure of 45 +/- 4 torr(SEM), accompanied by variable changes in ICP. PEEP application in the absence of oleic acid embolization of the lungs caused electroencephalographic abnormalities in 77% of these cats, while pupillary diameters increased in 56%. Animals embolized wwith oleic acid had significantly less (P less than .001) severe CPP reductions (mean 21 +/- 4 torr) than did the non-embolized animals, and developed no EEG change due to PEEP. However, increases in pupillary diameter still occurred in 33% of cats given oleic acid when PEEP was applied. In 82% of the PEEP applications (n = 44) in both experimental groups only insignificant increases in intracranial tension occurred (average peak ICP gain less than 1.5 torr). Abrupt increases in ICP exceeding 11 torr (15 cm H2O) occurred in four animals in each group. This happened most frequently (63 per cent) when the intracranial tension before PEEP was above 15 torr. Sudden removal of or reduction in PEEP was accompanied by increases in arterial and intracranial pressures in both groups, although this response was attenuated in the cats given oleic acid. The results indicate a potential for PEEP to evoke neurolgic complications in patients who have intracranial disease and that the presence of pulmonary disease may attenuate these deleterious side effects. Monitoring of neurologic function as well as blood-gas and cardiovascular effects of PEEP in patients who have intracranial disease is suggested.

UI	MeSH Term	Description	Entries
D007427	Intracranial Pressure	Pressure within the cranial cavity. It is influenced by brain mass, the circulatory system, CSF dynamics, and skull rigidity.	Intracerebral Pressure,Subarachnoid Pressure,Intracerebral Pressures,Intracranial Pressures,Pressure, Intracerebral,Pressure, Intracranial,Pressure, Subarachnoid,Pressures, Intracerebral,Pressures, Intracranial,Pressures, Subarachnoid,Subarachnoid Pressures
D008168	Lung	Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.	Lungs
D011175	Positive-Pressure Respiration	A method of mechanical ventilation in which pressure is maintained to increase the volume of gas remaining in the lungs at the end of expiration, thus reducing the shunting of blood through the lungs and improving gas exchange.	Positive End-Expiratory Pressure,Positive-Pressure Ventilation,End-Expiratory Pressure, Positive,End-Expiratory Pressures, Positive,Positive End Expiratory Pressure,Positive End-Expiratory Pressures,Positive Pressure Respiration,Positive Pressure Ventilation,Positive-Pressure Respirations,Positive-Pressure Ventilations,Pressure, Positive End-Expiratory,Pressures, Positive End-Expiratory,Respiration, Positive-Pressure,Respirations, Positive-Pressure,Ventilation, Positive-Pressure,Ventilations, Positive-Pressure
D011312	Pressure	A type of stress exerted uniformly in all directions. Its measure is the force exerted per unit area. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Pressures
D011655	Pulmonary Embolism	Blocking of the PULMONARY ARTERY or one of its branches by an EMBOLUS.	Pulmonary Thromboembolism,Thromboembolism, Pulmonary,Embolism, Pulmonary,Embolisms, Pulmonary,Pulmonary Embolisms,Pulmonary Thromboembolisms,Thromboembolisms, Pulmonary
D012025	Reflex, Pupillary	Constriction of the pupil in response to light stimulation of the retina. It refers also to any reflex involving the iris, with resultant alteration of the diameter of the pupil. (Cline et al., Dictionary of Visual Science, 4th ed)	Pupillary Reflex
D012123	Pulmonary Ventilation	The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.	Respiratory Airflow,Ventilation Tests,Ventilation, Pulmonary,Expiratory Airflow,Airflow, Expiratory,Airflow, Respiratory,Test, Ventilation,Tests, Ventilation,Ventilation Test
D001921	Brain	The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.	Encephalon
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D002496	Central Venous Pressure	The blood pressure in the central large VEINS of the body. It is distinguished from peripheral venous pressure which occurs in an extremity.	Venous Pressure, Central,Central Venous Pressures,Pressure, Central Venous,Pressures, Central Venous,Venous Pressures, Central