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At least 631 records · Page 35Linked to original sources

PubMed1982

Pressure-volume relationships above and below atmospheric pressure in the synovial cavity of the rabbit knee.

1. The pressure-volume relationship in the synovial cavity of the rabbit knee was investigated by the infusion of a non-absorbable oil into the cavity. 2. The pressure (P)-volume (V) curve was sigmoid. Its slope dP/dV (elastance) was steep at subatmospheric, physiological pressures, least steep at 5 cm H2O, and steepened progressively at higher, pathological pressures. 3. Elastance dP/dV was a good approximation to linear functions of P below atmospheric pressure and above 5 cm H2O. Each part of the pressure-volume relationship could therefore be described by an exponential expression. 4. Flexion of the joint increased pressure at a given volume. This was mainly due to steepening of the pressure-volume curve, and also partly due to a shift towards the pressure axis. 5. Pressure-volume curves determined by the infusion of normal saline or Krebs solution were grossly distorted, because these fluids were absorbed across the permeable synovium. 6. The physiological significance of the synovial pressure-volume curve is discussed, and mechanical explanations of the curve are suggested.

Animals↗

PubMed1988

Microvascular control of capillary pressure during increases in local arterial and venous pressure.

The extent to which capillary hydrostatic pressure might be protected from increases in local arterial and venous pressure was examined in the wing microcirculation of unanesthetized pallid bats (Antrozous pallidus). Arterial inflow and venous outflow pressures to the wing were elevated using a box technique to increase pressure around the body of the animal in steps of 12 mmHg between 0 and +60 mmHg for 3-min periods. During this time, hydrostatic pressure, diameter, and red cell velocity in single microvessels were continuously recorded. All branching orders of arterioles constricted significantly during increases in box pressure (Pb), while capillaries and venules dilated. First-order arteriole and venule pressures increased 1:1 with Pb. Capillary pressures increased by only a fraction of Pb up to +36 mmHg, but at higher Pb, the change in capillary pressure was equivalent to the change in Pb. Calculations of vascular resistance indicate that changes in both pre- and postcapillary resistance in this tissue act to prevent increases in capillary pressure during moderate, but not during large, increases in arterial and venous pressure.

Animals↗

PubMed1994

Increased lymphatic pressure without increased neck vein pressure during intravenous infusions.

Postnodal intestinal lymphatic pressure increases during rapid intravenous infusions with Ringer solution in sheep. Part of the lymphatic pressure increase is due to increased venous pressure at the lymphatic outflow (the neck veins). We tested the hypothesis that other factors besides increased neck vein pressure may cause increased lymphatic pressure during intravenous infusions. We placed cannulas into postnodal lymphatic vessels in eight sheep. After the sheep recovered from the surgery, we infused Ringer solution [46 +/- 21 (SD) ml/kg body wt in 30 min] intravenously into the sheep and inflated a balloon in the inferior vena cava. We adjusted the balloon inflation to prevent any increase in neck vein pressure during the infusions. At baseline, the intestinal lymphatic pressure was 15.5 +/- 2.5 cmH2O. During the infusions, lymphatic pressure increased significantly, and for the last 10 min of the infusion period, intestinal lymphatic pressure was 24.0 +/- 6.1 cmH2O. These results are consistent with the hypothesis that factors in addition to increased neck vein pressure may cause increased intestinal lymphatic pressure during rapid intravenous infusions.

Analysis of Variance↗

PubMed1993

Effect of vascular pressure on interstitial pressures in the isolated dog lung.

We report the first direct measurements of the effect of pulmonary vascular pressures on perialveolar interstitial pressures. In seven experiments we varied the intravascular pressure (Pvas) in isolated dog lungs held at constant airway pressure (PA). By the micropuncture servo-null technique, we recorded perialveolar interstitial pressures with respect to pleural pressure (0 cmH2O) at the alveolar junctions (Pjct) and in microvascular adventitia (Padv). At PA = 7 cmH2O, increase from 5 to 15 cmH2O did not affect Pjct, although it decreased Padv by 1.2 +/- 0.4 cmH2O. The Pjct-Padv gradient increased by 77%. Increasing Pvas to 25 cmH2O had no further effect on either interstitial pressure. In four experiments we also determined interstitial pressure in the hilum (Phil). When Pvas was increased from 5 to 15 cmH2O, Phil increased by 4.5 +/- 0.9 cmH2O. Further elevation of Pvas to 25 cmH2O increased Phil further by 2.4 +/- 0.4 cmH2O. At PA = 15 cmH2O, all interstitial pressures decreased, but their responses to Pvas were similar. We conclude that increase of Pvas 1) increases Phil but not perialveolar interstitial pressures and 2) increases the perialveolar interstitial pressure gradient, which may promote local liquid clearance.

Animals↗

PubMed2003

Cough gastric pressure and maximum expiratory mouth pressure in humans.

Maximal expiratory mouth pressure is a well established test that is used to assess expiratory muscle strength. However, low values are difficult to interpret, as they may result from technical difficulties in performing the test, particularly in patients with facial muscle weakness or bulbar dysfunction. We hypothesized that measuring the gastric pressure during a cough, a natural maneuver recruiting the expiratory muscles, might prove to be a useful additional test in the assessment of expiratory muscle function. Mouth expiratory and cough gastric pressures were measured in 99 healthy volunteers to obtain normal values and in 293 patients referred for respiratory muscle assessment to compare the two measurements. Between-occasion within-subject coefficient of variation, assessed in 24 healthy volunteers, was 10.3% for mouth pressure and 6.9% for cough. Mean +/- SD cough gastric pressure for normal males was 214.4 +/- 42.2 and 165.1 +/- 34.8 cm H2O for females. In 171 patients deemed weak by a low mouth expiratory pressure, 42% had a normal cough gastric pressure. In 105 patients deemed weak by a low cough gastric pressure, 5.7% had a normal expiratory mouth pressure. Low maximal expiratory mouth pressures do not always indicate expiratory muscle weakness. Cough gastric pressure provides a useful complementary test for the assessment of expiratory muscle strength.

Case-Control Studies↗

PubMed1991

Pulmonary "capillary" wedge pressure not the pressure in the pulmonary capillaries.

In 1949, Hellems, Haynes, and Dexter proposed that the pressure in a catheter wedged so as to occlude a pulmonary artery was an "estimate" of the pressure in the pulmonary capillaries. Their report led to the designation of this pulmonary artery wedge pressure as the pulmonary "capillary" wedge pressure. In fact, the pulmonary artery wedge pressure is a distorted measure of the pressure in the pulmonary veins. Usually this pressure differs only slightly from the capillary pressure, and the misconception fostered by the inaccurate name is inconsequential; however, sometimes this misconception leads to errors in diagnosis. This report briefly reviews the early history of pulmonary vascular catheterization, offers an explanation of pulmonary artery wedge pressure, and discusses a disease in which pulmonary artery wedge pressure is normal, even though capillary pressure is elevated.

Capillaries↗

PubMed2001

Novel method for intrafollicular pressure measurements in the rat ovary: increased intrafollicular pressure after hCG stimulation.

The ovulatory process in the rat comprises a period of about 12-15 h, from the time of the preovulatory LH surge to follicular rupture and extrusion of the oocyte. Follicular rupture is most likely caused, at least in part, by decreased tensile strength at the follicular apex due to degradation of collagen fibres of the extracellular matrix. It has been debated whether changes in intrafollicular pressure occur during the ovulatory process and whether such changes facilitate rupture of the follicle. In the present study, rats were primed with equine chorionic gonadotrophin (eCG, 10 iu) followed by hCG (10 iu) 48 h later. The intrafollicular pressure in the preovulatory follicle was recorded during 1 h at distinct time phases of the ovulatory process by use of an active servo-null pressure system based on the proportionality between electrical resistance and pressure within the tip of an inserted micropipette. The basal intrafollicular pressure was 16.6 +/- 1.0 mm Hg at the preovulatory phase (48 h after eCG) and increased gradually throughout the ovulatory process to 21.4 +/- 2.4 mm Hg at 4-7 h after hCG (mid-ovulatory phase) and 23.9 +/- 1.9 mm Hg at 8-12 h after hCG (late ovulatory phase; significantly higher (P < 0.01) than the preovulatory phase). Short-term peaks of increased pressure, possibly representing contractility, were not detected in follicles of the preovulatory phase, but were seen in most follicles of the mid- and late ovulatory phases. The mean amplitude of the short-term pressure increases was 12.3 +/- 3.2 mm Hg and the increases occurred at intervals of 24.7 +/- 3.6 s. These short-term increments in intrafollicular pressure were still present after hysterectomy had been performed. The wall tension index was calculated by measuring the follicular size and estimating the thickness of the follicle wall. The index increased from 93.9 +/- 13.3 at the preovulatory phase to 207.3 +/- 47.7 (mid-ovulatory phase) and to significantly higher values at the late ovulatory phase (320.9 +/- 33.5). In conclusion, this study shows that there is an increase in intrafollicular pressure in the ovulating follicle of the rat ovary during the late stages of the ovulatory process, and that short-term increases in intrafollicular pressure occur during the late phase of the ovulatory process. These changes in pressure may be essential for follicular rupture to proceed normally.

Animals↗

PubMedDate not supplied

Estimation of subglottal pressure with intraoral pressure.

A method of estimating subglottal pressure through intraoral pressure has been reported in the literature. In order to determine its clinical usefulness, however, the method should be tested against direct measurements made on subjects with pathologic larynges. The present study was designed to compare intraoral pressure versus subglottal pressure, as measured with a sensing tube inserted through a tracheal stoma. Results showed that intraoral pressure of /i:pi:/ was almost equivalent to subglottal pressure of /i:/ when the latter was smaller than about 25 cmH20. When subglottal pressure exceeded this value, however, the intraoral pressure was smaller than the subglottal pressure. We conclude that the magnitude of subglottal pressure is not invariably identical with intraoral pressure.

Aged↗

PubMed1984

Experimental normal-pressure hydrocephalus is accompanied by increased transmantle pressure.

This research was directed at the pathophysiology of normal-pressure hydrocephalus. The experimental method consisted of accurate and simultaneous measurement of the pressure within the ventricle and over the cerebral convexity in cats with hydrocephalus but normal ventricular pressure. Hydrocephalus was induced by the intracisternal injection of kaolin. Prior to the induction of hydrocephalus, the difference between the ventricular pressure and the pressure over the convexity (the transmantle pressure) was small (0.27 +/- 0.31 cm saline, mean +/- standard deviation). After the induction of normal-pressure hydrocephalus in seven animals, there was a statistically significant elevation of the transmantle pressure to 3.4 +/- 3.9 cm saline (p less than 0.05, Student's paired t-test). There was no similar increase in animals injected with lactated Ringer's solution. This finding supports the theory that it is the transmantle pressure, and not the ventricular pressure, that is the physiological determinant of ventricular dilatation. The theory explains why hydrocephalus can develop and persist despite normal ventricular pressure.

Animals↗

PubMed1999

[Postoperative hoarseness and sore throat after tracheal intubation: effect of a low intracuff pressure of endotracheal tube and the usefulness of cuff pressure indicator].

Many clinical reports have described postoperative hoarseness and sore throat after general anesthesia. In most cases, these symptoms were attributed to high pressure of the endotracheal tube cuff. The recommended cuff pressure is less than 25 mmHg, as excessive pressure produces ischemia of the tracheal mucosa. However, within the safe pressure range, postoperative hoarseness and sore throat are still often observed. In this study, one hundred and ninety patients of ASA classes I or II were allocated randomly to two groups, low cuff pressure group (< 15 mmHg) or high cuff pressure group (15-25 mmHg), using continuous monitoring with a cuff pressure gauge. We investigated the incidence of postoperative hoarseness and sore throat at 24 hours after intubation and on the seventh postoperative day. The incidence of postoperative hoarseness and sore throat was significantly decreased in the low pressure group at 24 hours after intubation as compared with the high pressure group, but there was no significant difference between the two groups on the seventh postoperative day. These results suggest that keeping the cuff pressure under 15 mmHg can prevent postoperative hoarseness or sore throat at 24 hours after intubation, and that a cuff pressure gauge is thought to be one of the indispensable monitors during anesthesia.

Adult↗

PubMed2000

Femoral artery pressures are more reliable than radial artery pressures on initiation of cardiopulmonary bypass.

OBJECTIVE: To compare radial and femoral artery perfusion pressure during initiation and various stages of cardiopulmonary bypass (CPB). DESIGN: Prospective study. SETTING: The cardiac center of a tertiary referral teaching institute. PARTICIPANTS: Sixty consecutive patients of all ages undergoing a variety of cardiac operations. INTERVENTIONS: Radial and femoral arterial pressures were measured in all patients on the same transducer, from the beginning to end of CPB. MEASUREMENTS AND MAIN RESULTS: Mean perfusion pressures on CPB measured at the femoral artery at 1, 5, 10, and 15 minutes of CPB were 38.4+/-3.6, 46.2+/-3.1, 49.7+/-3.9, and 52.8+/-4.1 mmHg and were significantly greater than the corresponding radial artery pressures (29.9+/-4.1, 35.3+/-6.1, 40.9+/-4.8, and 41.8+/-5.3 mmHg) (p < 0.001). At 30 minutes and 60 minutes of CPB, femoral artery pressures are higher (60.3+/-8.8 mmHg and 66.4+/-8.2 mmHg) compared with radial artery pressures (54.7+/-6.9 mmHg and 59.6+/-6.1 mmHg), but the difference is less significant (p < 0.05). On conclusion of CPB, mean femoral artery pressures (70.9+/-6.7 mmHg) are greater than mean radial artery pressures (67.6+/-8.1 mmHg) (NS). CONCLUSIONS: Although radial artery pressures are more commonly monitored during cardiac surgery, femoral artery perfusion pressures are more reliable during the initial part of CPB, and routine monitoring of femoral artery pressures may prevent vasoconstrictor use on initiation of CPB.

Adolescent↗

PubMed2002

Preshunt and postshunt portal vein pressures and portal vein-to-inferior vena cava pressure gradients do not predict outcome following partial portal decompression.

This study was undertaken to determine whether preshunt, postshunt, or changes in portal vein (PV) pressures or portal vein-to-inferior vena cava (PV-IVC) pressure gradients determine outcome following partial portal decompression attained through small-diameter prosthetic H-graft portacaval shunt (HGPCS). Seventy-seven adults underwent HGPCS (Child's class A 10%, B 56%, and C 34%) and were prospectively evaluated per protocol. PV pressures and PV-IVC pressure gradients decreased significantly in all patients with shunting (P < 0.001). Eight (10%) patients died within 30 days of shunting (Child's class B 50% and C 50%); seven of these deaths were due to liver failure. Preshunt, postshunt, and changes in PV pressures or PV-IVC pressure gradients with shunting were not different among eight perioperative deaths and survivors. At a mean follow-up of 3 years 24 (35%) additional patients died. Of late deaths 62 per cent were due to liver failure (Child's class B 40% and C 60%). Again preshunt, postshunt, or changes in PV pressures and PV-IVC pressure gradients with shunting did not predict who would die of late liver failure. We conclude that the small-diameter HGPCS effectively provides partial portal decompression. Preshunt or postshunt PV pressures or PV-IVC pressure gradients or changes in pressures with shunting do not determine outcome following HGPCS. Long-tern outcome is influenced by the severity of cirrhosis before shunting and by the self-destructive behaviors typical of patients with alcoholic cirrhosis.

Adult↗

PubMed2003

[Blood pressure volatility--a new parameter for determining blood pressure variability in type-1 diabetes mellitus].

INTRODUCTION: In diabetes the heart rate variability is decreased because of the autonomic neuropathy and parallel with this phenomenon the overnight blood pressure fall is lost. Presumably this change in the hemodynamic parameters is connected with the fact that the cardiovascular complications in type 1 diabetic patients are 2-4 times more frequent than in healthy patients. The volatility, as a new factor, is the dispersion of the proportion of the blood pressure values following each other. It exactly reflects the 24-hour blood pressure fluctuation, while the dipper/non-dipper determination differentiates only between the daytime and night-time average blood pressure values. The volatility follows the changes of the measured values in accordance to the frequency of the measurements during the whole day. AIM: Our aim was to compare the blood pressure variability of type 1 diabetic patients (DM) and healthy controls (C). PATIENTS AND METHODS: The authors examined 43 diabetic patients from our outpatient clinic and 45 healthy people. The blood pressures were measured with Meditech ABPM 02 monitor on workdays. The measurements started in the mornings. The frequency of the measurements was 20 minutes during the day and 50 minutes at night-time. The authors took the history of all the patients and detailed laboratory results. The patients also had ophthalmology examination, ECG and echocardiography tests. RESULTS: During the Ambulatory Blood Pressure Monitoring we found that the systolic volatility of blood pressure values was significantly lower in DM compared to C patients. Systolic volatility: 0.133 +/- 0.011 vs. 0.175 +/- 0.014 p < 0.026. Comparing only the normotonic C and DM group systolic volatility of blood pressure values were significantly lower in DM. Systolic volatility: 0.128 +/- 0.016 vs. 0.177 +/- 0.021 p < 0.036. CONCLUSION: It is an important new finding that in type 1 diabetic patient the volatility--a new parameter for determining blood pressure variability--is lower than in the healthy control group. At normotension state other parameters describing the blood pressure variability (like diurnal index or standard deviation) could not show this change.

Adult↗

PubMedDate not supplied

[Systolic blood pressures are not comparable when home blood pressure is measured with a wrist or an arm validated monitor].

OBJECTIVES: To compare home blood pressure values obtained with two validated OMRON (wrist or arm) monitors used sequentially in the same subject. METHODS: In 265 hypertensive subjects referred to hypertension specialists, a self measurement of blood pressure was performed sequentially with an OMRON M4-I (arm cuff, A/A, BHS validation) or OMRON RX-I (wrist cuff, B/B, BHS validation). Each patient recorded home blood pressure during two periods of 4 days with 3 measures in the morning and 3 in the evening. Order for use of each monitor was randomised. With wrist devices, subjects were advised to keep the arm at heart level during measurements. BP values were reported on a standardized document. Patients were asked by a questionnaire about the tolerance and feasibility of the 2 methods. RESULTS: In this population, aged 59 +/- 14 years, with 60% of men and a mean blood pressure of 152 +/- 21 / 86 +/- 14 mmHg, the home blood pressure values were 143 +/- 20/81 +/- 11 mmHg with the arm monitor and 135 +/- 10 / 80 +/- 11 mmHg with the wrist monitor. Mean SBP adjusted on age, initial blood pressure level and period order was significantly lower when home blood pressure monitoring has been recorded with a wrist monitor as compared to an arm monitor (p < 0.001). Self measurement of blood pressure was felt as easy in 92% with the arm monitor and in 96% with the wrist monitor (p < 0.05). Self measurement of blood pressure was felt as constraining in 14% with the arm monitor and in 7% with the wrist monitor (p < 0.01). The feasibility between the two devices was good with none of the value missing in 86% with the arm monitor and in 85% with the wrist monitor. The missing values were in 56% the fourth day. CONCLUSION: Despite the use of two validated monitors, mean SBP is significantly lower when home blood pressure monitoring is recorded with a wrist monitor as compared to an arm monitor. Uncertainty in the arm position with the use of wrist device could explain these results. When advising home blood pressure monitoring, care should be taken to recommend only the use of validated devices and to prefer the use of arm devices in order to avoid the uncertainty of an inadequate utilisation.

Adult↗

PubMed1988

24-hour blood pressure monitoring: evaluation of Spacelabs 5300 monitor by comparison with intra-arterial blood pressure recording in ambulant subjects.

The accuracy of 24-h blood pressure values obtained by ambulatory monitoring via the Spacelabs 5300 device was evaluated by comparison with simultaneous 24-h intra-arterial blood pressure recording from the contralateral arm. The comparison was made in eight essential hypertensive subjects in whom non-invasive blood pressure was measured every 15 (day) or 30 min (night). The measurements were automatically and visually edited to eliminate artefactual readings and hourly and 24-h means were calculated separately for systolic and diastolic blood pressure. The corresponding intra-arterial blood pressure means were also calculated. In the group as a whole, hourly means obtained by the non-invasive device were similar or only slightly different from those recorded intra-arterially. The 24-h systolic blood pressure mean obtained non-invasively was not significantly different from that obtained intra-arterially (138.4 +/- 9.1 and 142.9 +/- 9.2 mmHg, respectively), nor were the corresponding 24-h diastolic blood pressure means significantly different (83.5 +/- 4.5 and 80.6 +/- 3.5 mmHg, respectively). However, in spite of these similarities, there were contrasting and often large discrepancies between non-invasive and intra-arterial values in individual subjects. For the 24-h systolic blood pressure mean the discrepancies ranged from 7.6 +/- 1.1 to 16.1 +/- 2.2 mmHg and for the 24-h diastolic blood pressure mean, from 3.5 to 13.2 mmHg. Thus, the Spacelabs 5300 device has a limited ability to correctly estimate ambulatory blood pressure in individual subjects. It may be better suited for the estimation of group blood pressures, but only because errors are smoothed by the summation of individual errors of opposing signs.

Adult↗

PubMed1986

Pressure diuresis mechanism in the control of renal function and arterial pressure.

Precise knowledge of the interrelationships between arterial pressure and urinary excretion of sodium and water is crucial to understanding the long-term control of arterial pressure. Although increases in renal perfusion pressure have been known for more than 35 years to inhibit tubular reabsorption, the mechanism of this pressure diuresis response, the humoral or physical factors involved, and even the nephron segments in which the changes in tubular function occur remain relatively unknown. This review focuses on the experimental evidence that supports current hypotheses concerning the mechanism of pressure diuresis. Specifically, it examines the possibility that pressure diuresis is caused by a small increase in glomerular filtration rate, alterations in the humoral or physical factors regulating proximal tubular reabsorption, and/or inhibition of tubular reabsorption in deep nephrons secondary to changes in hemodynamics in juxtamedullary nephrons. The concept originally proposed that the kidney serves as the dominant long-term controller of arterial pressure is largely based on the assumptions that the pressure diuresis phenomenon exists and that it occurs via a nonadaptive mechanism. It has been proposed that hypertension can develop only if the relationship between arterial pressure and sodium excretion is shifted toward higher pressures. The remainder of this review examines recent evidence indicating that an abnormality in the pressure natriuresis relationship may be associated with the development of hypertension in humans and in the genetic rat models of the disease.

Absorption↗

PubMed1998

[Cardiovascular risk and ambulatory blood pressure measurement of arterial pressure].

Many studies have demonstrated that elevation of blood pressure is proportional to the risk of developing cardiovascular accidents. The relationship between blood pressure and cardiovascular risk varies according to whether diastolic, systolic or pulse pressure is considered. Several other parameters are involved in the determinism of the blood pressure risk such as age, gender, ethnic group, etc. These elements emphasize the importance of considering the various blood pressures as well of the patient's risk factors and clinical characteristics for global evaluation of the cardiovascular risk. As blood pressure is an eminently variable parameter and as the essential element of evaluation of the blood pressure risk is based on its determination, it is important to measure blood pressure accurately and precisely. Clinical measurement of BP constitutes the reference method, but presents several limits and several causes of error which raise the problem of its validity to evaluate a given patient's mean blood pressure. Ambulatory blood pressure monitoring during 24 hours of usual activity appears to more accurately evaluate the blood pressure load likely to induce organic lesions, as several studies have demonstrated its superiority over occasional measurement to evaluate the risk and cardiovascular prognosis of HT. However, whether its application in the evaluation of the global cardiovascular risk and therapeutic management can improve the prevention strategy and long-term cardiovascular prognosis has yet to be determined.

Blood Pressure Monitoring, Ambulatory↗

PubMed1992

High-frequency oscillatory ventilation compared with conventional mechanical ventilation in newborn lambs: effects of increasing airway pressure on intracranial pressures.

We tested the hypothesis that intracranial pressures and cerebral perfusion pressure in the newborn are more seriously affected by increasing airway pressure during high-frequency oscillatory ventilation (HFOV) than during conventional mechanical ventilation (CMV). Mean airway pressure was acutely elevated in stepwise fashion to 25 cm H2O in six anesthetized, paralyzed newborn lambs. Pressure (mean +/- SE) increased similarly during HFOV and CMV in the jugular vein (7 +/- 1 and 8 +/- 1 cm H2O, respectively), the sagittal sinus (6 +/- 1 and 7 +/- 1 cm H2O), and the cerebrospinal fluid of the lateral ventricle (4 +/- 1 and 6 +/- 1 cm H2O). Decreases in arterial blood pressure (-13 +/- 2 and -10 +/- 2 cm H2O) and cerebral perfusion pressure (-17 +/- 2 and -16 +/- 2 cm H2O) were also similar during HFOV and CMV. Intracranial pressure-volume curves were generated by incrementing cerebrospinal fluid volume in eight lambs. Curves generated during HFOV and CMV were similar, reflecting a similar intracranial compliance during the two ventilatory modes. These data indicate that intracranial compliance and the effects of increasing airway pressure upon intracranial pressures are not significantly different between HFOV and CMV.

Air Pressure↗