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Pressure Cuffs (pressure + cuff)

Distribution by Scientific Domains

Medical Sciences	60%
Life Sciences	40%

Selected Abstracts

Human cutaneous reactive hyperaemia: role of BKCa channels and sensory nerves

THE JOURNAL OF PHYSIOLOGY, Issue 1 2007
Santiago Lorenzo
Reactive hyperaemia is the increase in blood flow following arterial occlusion. The exact mechanisms mediating this response in skin are not fully understood. The purpose of this study was to investigate the individual and combined contributions of (1) sensory nerves and large-conductance calcium activated potassium (BKCa) channels, and (2) nitric oxide (NO) and prostanoids to cutaneous reactive hyperaemia. Laser-Doppler flowmetry was used to measure skin blood flow in a total of 18 subjects. Peak blood flow (BF) was defined as the highest blood flow value after release of the pressure cuff. Total hyperaemic response was calculated by taking the area under the curve (AUC) of the hyperaemic response minus baseline. Infusates were perfused through forearm skin using microdialysis in four sites. In the sensory nerve/BKCa protocol: (1) EMLA® cream (EMLA, applied topically to skin surface), (2) tetraethylammonium (TEA), (3) EMLA®+ TEA (Combo), and (4) Ringer solution (Control). In the prostanoid/NO protocol: (1) ketorolac (Keto), (2) NG -nitro- l -arginine methyl ester (l -NAME), (3) Keto +l -NAME (Combo), and (4) Ringer solution (Control). CVC was calculated as flux/mean arterial pressure and normalized to maximal flow. Hyperaemic responses in Control (1389 ± 794%CVCmax s) were significantly greater compared to TEA, EMLA and Combo sites (TEA, 630 ± 512, P= 0.003; EMLA, 421 ± 216, P < 0.001; Combo, 201 ± 200, P < 0.001%CVCmax s). Furthermore, AUC in Combo (Keto +l -NAME) site was significantly greater than Control (4109 ± 2777 versus 1295 ± 368%CVCmax s). These data suggest (1) sensory nerves and BKCa channels play major roles in the EDHF component of reactive hyperaemia and appear to work partly independent of each other, and (2) the COX pathway does not appear to have a vasodilatory role in cutaneous reactive hyperaemia. [source]

Effects of Ischaemia on Subsequent Exercise-Induced Oxygen Uptake Kinetics in Healthy Adult Humans

EXPERIMENTAL PHYSIOLOGY, Issue 2 2002
Michael L. Walsh
Leg muscles were occluded (33 kPa) prior to exercise to determine whether the induced metabolic changes, and reactive hyperaemia upon occlusion release just prior to the exercise, would accelerate the subsequent oxygen consumption (V,O2) response. Eight subjects performed double bouts (6 min duration, 6 min rest in-between) of square wave leg cycle ergometry both below and above their lactate threshold (LT). Prior to exercise, large blood pressure cuffs were put around the upper thighs. Occlusion durations were 0 min (control), 5 min and 10 min. Ischaemia was terminated within 5 s prior to exercise onset. Heart rate, V,O2, ventilatory rate (V,E), electromyogram (EMG) and haemoglobin/myoglobin (Hb/Mb) saturation were recorded continuously. Single exponential modelling demonstrated that, compared to control (time constant = 53.9 ± 13.9 s), ischaemia quickened the V,O2 response (P < 0.05) for the first bout of exercise above LT (time constant = 48.3 ± 14.5 s) but not to any other exercise bout below or above LT. The 3-6 min integrated EMG (iEMG) slope was correlated to the 3-6 min V,O2 slope (r = 0.73). Hb/Mb saturation verified the ischaemia but did not show a consistent relation to the V,O2 time course. Reactive hyperaemia induced a faster V,O2 response for work rates above LT. The effect, while significant, was not large considering the expected favourable metabolic and circulatory changes induced by ischaemia. [source]

Dynamic cerebral autoregulation in healthy adolescents

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2002
M. S. Vavilala
Background: There is little information on the limits of cerebral autoregulation and the autoregulatory capacity in children. The aim of this study was to compare dynamic cerebral autoregulation between healthy adolescents and adults. Methods: Seventeen healthy volunteers 12,17 years (n = 8) and 25,45 years (n = 9) were enrolled in this study. Bilateral mean middle cerebral artery flow velocities (Vmca; (cm/s)) were measured using transcranial Doppler ultrasonography (TCD). Mean arterial blood pressure (MAP) and end-tidal carbon dioxide were measured continuously during dynamic cerebral autoregulation studies. Blood pressure cuffs were placed around both thighs and inflated to 30 mmHg above the systolic blood pressure for 3 min and then rapidly deflated, resulting in transient systemic hypotension. The change of Vmca to change in MAP constitutes the autoregulatory response, and the speed of this response was quantified using computer model parameter estimation. The dynamic autoregulatory index (ARI) was averaged between the two sides. Results: Adolescents had significantly lower ARI (3.9 ± 2.1 vs. 5.3 ± 0.8; P=0.05), and higher Vmca (75.2 ± 15.2 vs. 57.6 ± 15.0; P<0.001) than adults. Conclusion: The autoregulatory index is physiologically lower in normal adolescents 12,17 years of age than in adults. [source]

Cuff compliance of pediatric and adult cuffed tracheal tubes: an experimental study

PEDIATRIC ANESTHESIA, Issue 8 2004
J.-M. Devys MD
Summary Background :,Tracheal mucosal damage related to tracheal intubation has been widely described in pediatric and adult patients. High volume,low pressure cuffs (HVLPC) are being advertised as safe to avoid this particularly unpleasant complication. Compliances of these supposed pediatric and adult HVLPC are not mentioned by manufacturers and still remain unknown. Methods :,The compliance of HVLPC was measured in vitro and defined as the straight portion of the pressure,volume curve. Cuff pressure was measured after incremental 0.1 ml filling volumes of air for sizes 3.0,8.0 of internal diameter of RüschTM and MallinckrodtTM tracheal tubes. Compliances were assessed in air and in a rigid tube. The filling volume to achieve a 25-mmHg intracuff pressure was also measured. Results :,In air, each 0.1 ml step almost linearly increased cuff pressure by 1 mmHg (size 8.0) to 9 mmHg (size 3). In air, the volume needed to maintain a cuff pressure < 25 mmHg was small for sizes 3,5.5 (0.35,2 ml). The 25 mmHg inflated cuff volume and compliance were decreased within a rigid tube, especially for adult sizes. In a rigid tube simulating a trachea, the compliances of almost every RüschTM tracheal tube were statistically higher than those of the MallinckrodtTM. Conclusion :,We conclude that the tested tracheal tube cuffs have low compliance and cannot be defined as high volume,low pressure. [source]

Endobronchial argon plasma coagulation for the management of post-intubation tracheal stenosis

RESPIROLOGY, Issue 5 2006
Masanori YASUO
Abstract: Post-intubation tracheal stenosis is usually caused by pressure necrosis at the cuff. Despite the fact that this phenomenon is well known and both large volume and low pressure cuffs have been developed, this lesion nevertheless continues to occur. Although the best results for tracheal reconstruction are obtained by an experienced surgeon, not all patients are able to undergo this operation for either medical or personal reasons. Argon plasma coagulation (APC) using flexible bronchoscopy has been successfully employed in the treatment of post-intubation tracheal stenosis in two of the surgery-refused and inoperable patients. The patients immediately experienced a relief of symptoms after APC. APC was thus performed 3,4 times every 1,2 weeks for each patient. In addition, there were no complications related to this procedure. The number of published clinical reports describing APC in benign airway stenosis are increasing. APC has also been reported to have several advantages over other interventional endobronchial techniques in the management of tracheo-bronchial stenosis. We report two patients, and to our knowledge this is the first description of APC being used in the treatment of endobronchial dilatation for post-intubation tracheal stenosis. [source]