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At least 127 records · Page 7Linked to original sources
PubMed2006

Pressure-relief continuous positive airway pressure vs constant continuous positive airway pressure: a comparison of efficacy and compliance.

OBJECTIVES: To compare polysomnographic data and compliance in sleep apnea patients receiving continuous positive airway pressure (CPAP) and pressure-relief CPAP (PRCPAP) [C-flex; Respironics; Murrysville, PA] as first treatment in the sleep laboratory and subsequently at home. DESIGN: A prospective, randomized, crossover design was used in the sleep laboratory, and a prospective randomized design was used at home. PATIENTS: Data were collected from 52 sleep apnea patients for whom CPAP was used for the first time. INTERVENTIONS: Treatment with constant CPAP and PRCPAP. MEASUREMENTS AND RESULTS: Patients with a first-time diagnosis of obstructive sleep apnea syndrome (OSAS) underwent conventional CPAP titration. Thereafter, polysomnography was performed at the titrated pressure using both the fixed CPAP pressure mode and the PRCPAP mode in a randomized crossover approach. The patients were then discharged home for 7 weeks of treatment with the last-applied treatment mode, and compliance data were established at the end of that time. The average apnea-hypopnea index was 53.3/h in the "diagnostic night," 5.8/h with CPAP, and 7.0/h with PRCPAP. The native arousal index was 35.2/h, 12.6/h with CPAP, and 12.9/h with PRCPAP (not significant [NS]). The central apnea index was 0.7/h with CPAP and 1.2/h with PRCPAP (p < 0.05). Compliance after 7 weeks was, on average, 9.4 min longer with PRCPAP than with CPAP (NS). Evaluation of a 13-item questionnaire showed scores of 16.4 for PRCPAP and 18.1 for constant CPAP (NS) [the fewer the complaints, the lower the score]. With regard to oral dryness, the score with PRCPAP (1.4) was significantly lower than with constant CPAP (1.9) [p < 0.05]. This difference was no longer detectable after 7 weeks. CONCLUSION: In terms of the effectiveness in treating obstructive sleep apnea, PRCPAP and constant CPAP are comparable. During the first night of treatment, patients receiving PRCPAP had less dryness of mouth; over a period of 7 weeks, this difference disappeared. Nightly use of the device was comparable in both groups. PRCPAP is therefore a new ventilation mode that enables effective treatment of OSAS patients. Further studies should be done to investigate the effects of expiratory pressure lowering in low-compliance patients and patients requiring CPAP > 9 cm H(2)O or experiencing dry mouth with CPAP.

Adult↗
PubMed1992

[Extending informative value of intracranial pressure measurement by cerebral pressure amplitudes (Pa)--analysis of average intracranial pressure (Pm)].

One aim of the intracranial pressure measurement is observing constantly patients with intracranial space-occupying factors and therefore to act diagnosticly and therapeutically correct at the right time. Through the continual registration of the intracranial pressure amplitude in relation to the medium intracranial pressure it is earlier possible to forecast intracranial pressure rise and to deal with this than with just the simple measurements of medium intracranial pressure. With 40 neurosurgical patients such examinations were undertaken after implantation of a ventricle catheter. The value of this method was proven during the continual observation of the patient.

Brain Injuries↗
PubMed2005

Recommendations for blood pressure measurement in humans and experimental animals: part 1: blood pressure measurement in humans: a statement for professionals from the Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research.

Accurate measurement of blood pressure is essential to classify individuals, to ascertain blood pressure-related risk, and to guide management. The auscultatory technique with a trained observer and mercury sphygmomanometer continues to be the method of choice for measurement in the office, using the first and fifth phases of the Korotkoff sounds, including in pregnant women. The use of mercury is declining, and alternatives are needed. Aneroid devices are suitable, but they require frequent calibration. Hybrid devices that use electronic transducers instead of mercury have promise. The oscillometric method can be used for office measurement, but only devices independently validated according to standard protocols should be used, and individual calibration is recommended. They have the advantage of being able to take multiple measurements. Proper training of observers, positioning of the patient, and selection of cuff size are all essential. It is increasingly recognized that office measurements correlate poorly with blood pressure measured in other settings, and that they can be supplemented by self-measured readings taken with validated devices at home. There is increasing evidence that home readings predict cardiovascular events and are particularly useful for monitoring the effects of treatment. Twenty-four-hour ambulatory monitoring gives a better prediction of risk than office measurements and is useful for diagnosing white-coat hypertension. There is increasing evidence that a failure of blood pressure to fall during the night may be associated with increased risk. In obese patients and children, the use of an appropriate cuff size is of paramount importance.

Adult↗
PubMed2001

Influence of positive end-expiratory pressure on intracranial pressure and cerebral perfusion pressure in patients with acute stroke.

BACKGROUND AND PURPOSE: We undertook this study to evaluate the influence of positive end-expiratory pressure (PEEP) on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in patients with acute stroke. METHODS: A total of 20 ventilated patients of a neurological intensive care unit were examined under a protocol entailing variation of PEEP to 4, 8, 12, and 4 mm Hg; mean arterial blood pressure (MAP), ICP, heart rate, and mean velocity of the middle cerebral arteries (V(m) MCA) were recorded. RESULTS: CPP significantly changed depending on the various PEEP levels. No significant differences in remaining parameters were evident. Three distinct reaction patterns of the parameters monitored were observed: (1) All parameters remained stable through the various PEEP levels (15 patients, 40 examinations). (2) Increase in PEEP resulted in a significant decrease of MAP, while V(m) MCA remained unchanged, indicating an intact cerebral autoregulation. A slight (statistically insignificant) increase in ICP, which was significantly related to the MAP changes, was evident (7 patients, 16 examinations). (3) Increase in PEEP resulted in a decrease of MAP and V(m) MCA; ICP remained unchanged or demonstrated a slight decline (3 patients, 6 examinations). CONCLUSIONS: PEEP increase up to 12 mm Hg does not significantly influence ICP. The observed marked changes in CPP are mediated through the MAP. Thus, PEEP application should be safe, provided that MAP is maintained.

Adult↗
PubMed2002

[Comparison of clinical arterial pressure, home-arterial pressure measurement, and ambulatory arterial pressure monitoring in patients with type II diabetes mellitus and diabetic nephropathy].

BACKGROUND: Hypertension is common in type 2 diabetes with diabetic nephropathy, and increases the risk of cardiovascular complications and renal chronic insufficiency. The aim of our evaluation in these patients was: a) to study the correlation between office blood pressure (BP), self-monitored (SMBP) and 24-hour ambulatory blood pressure monitoring (ABPM). b) To study the correlation between these methods and cardiovascular and renal complications. METHODS: We studied 60 patients (mean age 66.7 +/- 9 years, mean duration of diabetes 11.3 +/- 7 years) with arterial hypertension, type 2 diabetes and diabetic nephropathy. Macroangiopathy and echocardiography were recorded. We measured, SMBP and ABPM without modifying the antihypertensive treatment. The white coat phenomenon (WCP) was determined and patients were classified as dippers or non dippers according to their blood pressure diurnal rhythm. RESULTS: Mean glycated haemoglobin was 7.8% and mean serum creatinine 1.2 +/- 0.5 mg/dl, 30% of patients had proteinuria and 70% microalbuminuria The mean number of antihypertensive drugs was 2.2 +/- 1. The mean BP was: Office BP: 158.2 +/- 24/85.3 +/- 9 mmHg, pulse pressure (PP) 72.9 +/- 21 mmHg; SMBP: 145.4 +/- 18/77.5 +/- 7 mmHg, PP 67.9 +/- 18 mmHg and BP in the early morning 150.2 +/- 20/79.9 +/- 9 mmHg; ABPM: diurnal mean 138.9 +/- 15/74.1 +/- 6 mmHg, PP 64.8 +/- 15 mmHg and BP in the early morning 146.5 +/- 16/78.5 +/- 7 mmHg. The three techniques showed a good correlation and WCP was detected in 46.7% of patients with SMBP and in 56.7% with ABPM. We found no correlation between BP and macroangiopathy, but an increase of systolic BP in SMBP and ABPM in proteinuric patients were found and correlation between mass left ventricular index (MLVI) and PP in office and systolic BP and PP in SMBP and ABPM was significant. 70% of patients were non dippers, with a higher MLVI. CONCLUSIONS: Decreases in BP in type 2 diabetes with diabetic nephropathy are difficult of maintain despite combinations of different antihypertensive drugs. These patients present an important WCP and worse prognosis data, such as elevation of systolic BP, increased PP, poor night BP fall and a BP rise in the early morning. Also, we can't reduced the BP during 24 hours in an important number of patients. These characteristics can be detected by combining the office BP measurement, SMBP and ABPM. The alternative possibility would be lifestyle modification, appropriate drug combinations and to start treatment at lower levels than those currently used as thresholds (the guidelines for antihypertensive treatment have been drastically shifted in this direction over the past years).

Aged↗
PubMed2002

Effects of positive end-expiratory pressure on intracranial pressure and cerebral perfusion pressure.

The effect of positive end-expiratory pressure (PEEP) on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) has been reported by several investigators, without any consensus being reached. Acute neurological and neurosurgical patients suffer intracranial hypertension and acute lung injury with hypoxemia. Since PEEP may improve hypoxemia but elevate ICP and decrease CPP, it is important to determine the influence of varying levels of PEEP on ICP and CPP. The aim of the study was to investigate the changes in ICP and CPP associated with different levels of PEEP. Twenty patients requiring ICP monitoring and mechanical ventilation were enrolled. Patients had severe head injury (n = 10), spontaneous intracerebral haemorrhage (n = 5), and subarachnoid haemorrhage (n = 5). PEEP was raised from 5 (basal) to 15 cm H2O in steps of 5 cm H2O. After at least 10 minutes of each new PEEP setting, ICP and CPP were measured. PEEP at 10 and 15 cm H2O produced a significant (p < 0.05) increase in intracranial pressure 11.6 +/- 5.6 and 14.6 +/- 6.28 mm Hg, respectively; no significant (p = 0.819) change occurred in CPP.

Adult↗
PubMed1997

24 h blood pressure profile affects the left ventricle independently of the pressure level. A study in untreated essential hypertension diagnosed by office blood pressure readings.

This work examines whether the 24 h blood pressure (BP) pattern per se might affect the left ventricular structure independently of the pressure level. One hundred subjects with abnormally high office BP readings who had never received any antihypertensive treatment were submitted to 24 h ambulatory BP monitoring and left ventricular echocardiographic assessment. They were classified into two groups, as follows: dippers (group 1), consisting of 46 subjects whose mean nighttime systolic BP was reduced by at least 10% in comparison to the corresponding daytime value, and nondippers (group 2), consisting of 54 subjects whose nighttime BP did not drop or was reduced by < 10%. Left ventricular mass and end-diastolic volume values, both normalized for body surface area, were significantly higher in nondippers (r = 3.12, P < .003, and r = 7.46, P < .001, respectively). The two groups did not differ in diastolic thickness of either intraventricular septum or left ventricular posterior wall (both values normalized for body surface area), in mean 24 h systolic or diastolic or average blood pressure, or in age. In conclusion, in untreated essential hypertension diagnosed on the basis of abnormal office BP readings, the higher incidence of left ventricular mass increase in subjects unable to reduce their blood pressure during the night was more due to left ventricular dilatation than to myocardial wall thickening. The effect of the 24 h BP profile on left ventricular volume appears to be independent of both the BP level and age.

Adult↗
PubMed1984

Intra-abdominal pressure measurements using a wireless radio pressure pill and two wire connected pressure transducers: a comparison.

Intra-abdominal pressures were measured simultaneously with a wireless radio pill and two wire-connected pressure transducers introduced orally and rectally respectively. Measurements were made on 8 men during common postures, simple activities and static and dynamic lifting. An acceptable correspondence was found in wave forms of the generated pressure curves in time and shape. The three systems showed, however, a less good agreement in recorded peak differences, i.e. highest and lowest pressure responses to each task. The radio pill is simple to use, but more difficult to calibrate and expensive, compared to the wire-connected methods, which however are less attractive for use in the work environment.

Abdomen↗
PubMed1995

[Correlation between the gradient constant of the theoretical pressure volume diagram (PVD) and the pressure volume index (PVI) in relation to brain pulse amplitude-mean pressure function].

In 54 neurosurgical patients--suffering from intracranial tumors, hydrocephalus or different kinds of brain injury--a catheter was implanted in the lateral ventricle for continuously monitoring of the intracranial pressure (ICP). The intraventricular injection of defined amounts of sodium clearance (1-2 cm3) was followed by increased values of intracranial mean pressure--(pm) and pulse-amplitude- (PA). The recorded data showed a high significant correlation after regression analysis. After determination of the pressure-volume-index (PVI) and the theoretical pressure-volume-diagram it was examined whether there is a linear correlation between the parameters of the craniospinal space (id) reserves (constant of gradient, (PVI, K of PVD)) and the gradients (CA) of the linear PA-PM-function. A significant linear relationship, however of weak degree, could be found between these two parameters. The linear PA-PM-function, therefore, can only be understood in restricted circumstances as a direct parameter of the intracranial spacial reserves. The underlying facts of these problems are dealt within this paper.

Brain Injuries↗
PubMed1991

Intracranial pressure monitoring using a programmable pressure valve and a telemetric intracranial pressure sensor in a case of slit ventricle syndrome after multiple shunt revisions.

A case of hydrocephalus showing slit ventricle syndrome after multiple shunt revisions was treated with a programmable pressure valve, and intracranial pressure was monitored with a telemetric sensor. High pressure setting produced positive and normal values of intracranial pressure in this patient. We report our experiences.

Cerebrospinal Fluid Shunts↗
PubMed2003

Correlation among maximal urethral closure pressure, retrograde leak point pressure, and abdominal leak point pressure in men with postprostatectomy stress incontinence.

OBJECTIVES: To assess the correlation among abdominal leak point pressure (ALPP), maximal urethral closure pressure (MUCP), and retrograde leak point pressure (RLPP) in the evaluation of men with stress urinary incontinence (SUI) after radical prostatectomy. METHODS: Patients were evaluated with a self-administered questionnaire regarding pad use and with multichannel videourodynamics. The ALPP, MUCP, and RLPP were compared with each other and with the severity of SUI. RESULTS: The mean ALPP was 49.4 +/- 24.4 cm H(2)O. The mean MUCP was 52.0 +/- 21.1 cm H(2)O. The mean RLPP was 48.0 +/- 13.5 cm H(2)O. No statistically significant difference in the mean values of the three parameters was found. Regression analysis revealed a statistically significant correlation among the three parameters: RLPP versus MUCP, r = 0.59, P <0.005; MUCP versus ALPP, r = 0.75, P <0.0001; and RLPP versus ALPP, r = 0.79, P <0.0001. ALPP, MUCP, and RLPP were each significantly related to pad use. CONCLUSIONS: Intrinsic sphincter deficiency is the primary cause of SUI after radical prostatectomy. Therefore, evaluation of intrinsic sphincter function is important in the treatment of postprostatectomy SUI. In incontinent men after radical prostatectomy, with a dysfunctional bladder neck and proximal sphincter unit, the intrinsic function of this distal sphincter may be assessed equally well by evaluating the resistance to antegrade leakage, retrograde leakage, or profilometric measurement of the urethral closure pressure. RLPP and MUCP offer reliable alternatives to ALPP for the evaluation of postprostatectomy SUI.

Adenocarcinoma↗
PubMed2003

Influence of L-nitro-arginine methyl ester, acetylcholine, and adenosine on mean blood pressure, pulse pressure, and pulse pressure amplification in rats.

The blood pressure pattern in spontaneously hypertensive rats (SHRs) involves three main characteristics: increase in mean blood pressure (MBP); increase in thoracic aorta (proximal) and iliac (distal) pulse pressure (PP); disappearance of the normal PP amplification between the proximal and the distal arteries. Whether pharmacologic agents may reduce MBP with different or even opposite effects regarding PP and PP amplification has been poorly investigated. In SHRs and Wistar-Kyoto (WKY) anesthetized rats, the NO inhibitor l-nitro-arginine methyl ester (l-NAME) was infused at the dosage of 1 mg/kg for 30 min. Before and after infusion, 7 microg/kg/min acetylcholine (Ach) and 200 mg/kg adenosine (Ado) were perfused for 4 min. Proximal and distal intra-arterial BP was monitored throughout the procedure. In both WKYs and SHRs, l-NAME increased proximal and distal systolic (SBP), diastolic (DBP), and MBP but not PP. Before l-NAME, SBP, DBP, and MBP were significantly reduced by Ado and Ach. After l-NAME, such blood pressure reductions were abolished with Ach but not Ado. In both strains, the proximal and distal PP, when expressed in percent reduction of MBP, were significantly higher under Ado than under Ach. The Ado but not Ach changed PP amplification, causing a reduction in WKYs and an increase in SHRs independent of l-NAME. Vasodilating agents may reduce MBP with significantly different effects on PP. The Ado alters PP amplification, an effect not obtained with the nitric oxide endothelium-dependent vasorelaxing agent Ach. Tail SBP measurements cannot predict such dissociated changes.

Acetylcholine↗
PubMed1998

Pressure ulcer research: pressure ulcer treatment. A monograph from the National Pressure Ulcer Advisory Panel.

The AHCPR guideline on Treatment of Pressure Ulcers was released in December 1994. This guideline was based on the best available scientific evidence published between 1966 and May 1, 1993. Over 45,000 abstracts were reviewed in the literature analysis. Yet only 63.2% of the guideline recommendations were based on research of any type, and only 4.5% of the recommendations were supported by two or more randomized clinical trials. A more recent literature review (covering articles on pressure ulcers listed in the MEDLINE database between May 1, 1993, and December 1, 1996), revealed minimal advances in the scientific body of knowledge on pressure ulcer treatment. Advances have been made in the knowledge of electrical therapy and growth factors, and efforts are under way to enhance tools for monitoring healing. In an era of limited research funding, we need to carefully target our research efforts to maximize the advancement of our knowledge of pressure ulcer treatment. It is the hope of the NPUAP that this monograph will guide the research needed to ensure the most efficient utilization of funds to improve patient outcomes.

Evidence-Based Medicine↗
PubMed1986

The effects of acute high dose fentanyl administration on experimental brain edema: analysis of intracranial pressure, systemic arterial pressure, central venous pressure and brain water content.

In rabbits who had brain edema and intracranial hypertension induced by a combined cold lesion (over the left hemisphere) and a metabolic blocker (6-aminonicotinamide), the authors analyzed the response of multiple parameters following the administration of 6 mcg/kg/dose of fentanyl every 5 minutes for 1 hour (12 doses), combined with nitrous oxide anesthesia. All animals were mechanically ventilated and the PaCO2 was maintained at 37-43 torr. Gross pathology and extent of Evans Blue extravasation was no different from pretreatment control animals. The systolic arterial pressure and the central venous pressure showed no change during the experiment. The intracranial pressure remained elevated despite fentanyl, but did not increase or decrease throughout the administration of the agent. The brain water content remained unchanged in the right hemisphere, but revealed a significant increase following fentanyl in the cold-lesioned left hemisphere for the gray (p less than 0.005) and white matter (p less than 0.05).

Animals↗
PubMed1990

Minimum airway pressure weaning. Weaning from mechanical ventilation at 50 breaths/minute by reduction of inflation pressure using a pressure generator.

Ten patients, whose lungs were ventilated initially with intermittent positive pressure ventilation at conventional rates after myocardial revascularisation or cardiac valvular surgery, were weaned using a valveless high frequency jet ventilator at a constant rate of 50 breaths/minute. The withdrawal of ventilation was achieved, when clinical criteria permitted, by reduction of the tidal volume preset on the jet ventilator in successive stages; this was effected by stepwise decreases in the jet driving pressure. This new mode of weaning at a constant rate of 50 breaths/minute is associated with minimum peak airway pressures. Synchronisation of the patient's breathing with the valveless ventilator is not required and weaning is tolerated well by the patient. Arterial oxygen tension and saturation were maintained throughout weaning and did not decline after extubation of the trachea.

Adult↗
PubMed1981

Acute dimethyl sulfoxide therapy in experimental brain edema: Part I. Effects on intracranial pressure, blood pressure, central venous pressure, and brain water and electrolyte content.

Albino rabbits with experimental brain edema produced by a cryogenic lesion or by a cryogenic lesion combined with a metabolic blocker, 6-aminonicotinamide, were given 1 g of a 10% solution of dimethyl sulfoxide (DMSO) per kg by intravenous bolus. Simultaneous recording of intracranial pressure (ICP), systemic arterial pressure (SAP), and central venous pressure and electroencephalography were performed while the animals were mechanically ventilated at a constant PaCO2 (PaCO2, 38 to 42 torr). One hour after the administration of DMSO, the rabbits were killed by air embolus, and the brain was removed promptly for the determination of wet and dry weights and electrolyte content. The ICP at 15, 30, and 60 minutes after DMSO was lower in both groups; ICP was significantly lower at 30 minutes (p less than 0.5) in the cold lesion group and at 15 minutes in the combined group (p less than 0.05). These was no significant change in SAP after DMSO in either group. There was s significant reduction of brain water content after DMSO in the combined lesion group (p less than 0.005 for the left hemisphere and p less than 0.025 for the right); there was no significant reduction of water content in the group with a cold lesion only.

Animals↗
PubMed1982

Acute dimethyl sulfoxide therapy in experimental brain edema: part 2. Effect of dose and concentration on intracranial pressure, blood pressure, and central venous pressure.

Albino rabbits with experimental brain edema produced by a combined cryogenic and metabolic 6-aminonicotinamide lesion were administered intravenous dimethyl sulfoxide in varying concentrations and doses in the following manner: Subgroup A (concentration response) received a 1.0-g/kg bolus as a 10%, 20%, 30%, or 40% solution. Subgroup B (dose response) received as a 20% solution a 1.0-g/kg bolus, 1.5-g/kg bolus, or 2.0-g/kg infusion. Simultaneous recording of intracranial pressure (ICP), systolic arterial pressure (SAP), and central venous pressure and electroencephalography were performed while the animals were being mechanically ventilated at a constant PaCO2 (38 to 42 torr). There was significant lowering of ICP when compared to pretreatment values in Subgroup A in the 10% subset at 30 minutes (p less than 0.05) and in the 20% subset at 5 (p less than 0.05) and 30 (p less than 0.05) minutes. ICP was not significantly decreased in the 30% and 40% subsets. All animals of Subgroup B displayed significant reductions of ICP when compared to their pretreatment values. There was no significant change in SAP in either subgroup.

6-Aminonicotinamide↗
PubMed1985

Experimental carbon dioxide laser brain lesions and intracranial dynamics: Part 1. Effect on intracranial pressure, systemic arterial pressure, central venous pressure, electroencephalography, and gross pathology.

Experimental brain lesions were created in the left parietooccipital cortex of the albino rabbit through the intact dura mater with high radiating carbon dioxide laser energy (40-watt impacts of 0.5-second duration for a total of 4 seconds on a 12.5-mm surface). Behavior, intracranial pressure (ICP), systolic arterial pressure (SAP), central venous pressure (CVP), electroencephalography (EEG), and gross pathology were studied at 2, 6, and 24 hours after the insult at a constant PaCO2 (38-42 torr). Disruption of the blood-brain barrier (Evans blue extravasation) was uniformly seen extending from the impact crater into the surrounding white matter in all groups. The ICP was elevated in sham-operated animals at 2 hours after the impact, and it remained elevated at 6 and 24 hours. The EEG revealed severe slowing with high voltage waves in the insulted left hemisphere. There was no change in mean SAP or CVP when compared to the sham-operated group. In the dexamethasone-pretreated group, there was a reduction of ICP when compared to the untreated group at 24 hours after the insult (P less than 0.005), but no changes in the gross pathology were noted.

Animals↗