Ruptured abdominal aortic aneurysms: a new perspective.
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Aortic Aneurysm, Abdominal↗
Biomedical subjects
K R Patel
Publications and source records attributed to K R Patel.
A technique to prevent detachment of the Fogarty catheter from the Leather valve cutter during in situ bypass.
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Catheterization↗
Metastatic breast cancer presenting as an ovarian cyst: diagnosis by fine needle aspiration cytology.
A fifty-year-old woman with a history of breast cancer presented with a clinically benign ovarian cyst. Laparoscopic aspiration of cyst fluid was performed and the cytology was suspicious of epithelial neoplasia. At subsequent hysterectomy and bilateral salpingo-oophorectomy, the specimen showed extensive metastatic breast carcinoma. Although the cytological examination of fluid from ovarian cysts is often unrewarding, this case shows that metastatic carcinoma may occasionally be diagnosed in this fashion.
Biopsy, Needle↗
Dose duration of nebulized nedocromil sodium in exercise-induced asthma.
The dose-duration effect of nebulized nedocromil sodium was studied in ten patients with exercise-induced asthma (7 males mean (SEM) age 30.1 (3.5) yrs and predicted forced expiratory volume in one second (FEV1) 102%). All of these patients showed > 40% protection of their exercise asthma with 4 mg of nedocromil sodium delivered via metered dose inhaler. Three concentrations of nedocromil sodium (0.5, 2.5 and 10 mg.ml-1) and placebo were administered in double-blind, randomized manner. One ml of each solution was nebulized via a Wright nebulizer. Effects were assessed from the mean maximal percentage fall in FEV1 after 6-8 min treadmill exercise at 15, 135 and 255 min following each treatment and expressed as percentage protection. The mean baseline FEV1 values before and after treatments were comparable on four days of testing. Nedocromil sodium inhibited exercise-induced fall in FEV1 at all concentrations (p < 0.001) and the inhibitory effect was still present at 255 min. No differences were observed between active treatments.
Adult↗
Effect of cetirizine on histamine- and leukotriene D4-induced bronchoconstriction in patients with atopic asthma.
Cetirizine, a derivative of hydroxyzine, is a new compound with potent antihistaminic property without antiserotonin and anticholinergic activities. The effect of both a single dose (15 mg) and 7 days of treatment (15 mg twice daily) with cetirizine, a potent H1 antagonist on bronchoconstriction induced by histamine and leukotriene D4 (LTD4) has been examined in 10 patients with mild atopic asthma in a placebo-controlled, double-blind, crossover study. Cetirizine, after a single dose and 7 days of treatment with placebo, the geometric mean values of the provocative concentration of histamine causing a 20% fall in FEV1 (millimolars) were 1.60 (95% confidence interval, 0.82 to 3.11) and 1.67 (0.77 to 3.65), compared with 118.07 (77.22 to 180.54) (p less than 0.0001) and 53.16 (20.50 to 137.84) after cetirizine administration (p less than 0.0002). The mean inhibition after a single dose was twofold higher than after 1 week of treatment (p less than 0.05). After a single dose and 7 days of treatment with placebo, the geometric mean values of the provocative concentration of LTD4 causing a 20% fall in FEV1 (micromolars) were 2.26 (1.74 to 2.94) and 2.37 (1.77 to 3.17), compared with 3.90 (2.60 to 5.86) (p less than 0.05) and 3.21 (2.28 to 4.52) after cetirizine administration. This result suggests that cetirizine is a potent H1 antagonist in the human airways. Diminished activity after 1 week of treatment suggests subsensitivity of H1 receptors developing in human airways. The small protective effect after a single dose against LTD4-induced bronchoconstriction indicates a nonspecific rather than a specific receptor antagonism.
Adult↗
Subclavian artery to innominate vein fistula after insertion of a hemodialysis catheter.
Insertion of hemodialysis catheters for temporary use is now preferentially performed by percutaneous infraclavicular subclavian vein catheterization. This method involves passage of a stiff dilator and a peel-away sheath over a guide wire, and is usually carried out without fluoroscopy. For the most part this has proved to be a valuable and safe approach. However, a small incidence of major complications occurs, which needs to be emphasized. Sixteen cases of arteriovenous fistulas between the subclavian artery or its branches and the subclavian vein have been reported so far in the literature. To date only one case of subclavian artery to innominate vein fistula has been reported. We report the second case with this complication and suggest possible preventive measures.
Adult↗
Lack of dose-response effect of terfenadine on resting bronchomotor tone in patients with asthma.
Bronchodilatation data from three, four-period cross-over studies were combined to assess the effect of oral terfenadine 60, 120, 180 mg and placebo on the airways of 26 patients with atopic asthma. Meta-analysis of these data showed that mean changes in FEV1 from pre-dose to 4 hr were 11.4, 14.6 and 11.8% for the three doses of terfenadine, respectively, and -2.9% for placebo. There was a significant treatment effect (P = 0.0001) but no effect of dose. Terfenadine, a non-sedating histamine H1-receptor antagonist, caused bronchodilatation in a single dose. Whether this effect is sustained with long-term treatment requires further investigation.
Adolescent↗
Effect of cetirizine on exercise induced asthma.
The effect of oral and inhaled cetirizine, a potent and specific H1 receptor antagonist, was studied in patients with exercise induced asthma. Twelve patients (five male; mean age 35.2 years) were given oral placebo or cetirizine 10 mg twice daily for one week, double blind and in randomised order, and exercised on a treadmill for six to eight minutes at a submaximal work load two hours after the final dose. There was no significant change in baseline FEV1 after treatment and cetirizine failed to inhibit exercise induced bronchoconstriction (maximum falls in FEV1 28% and 27% of baseline). In a further eight patients (four male; mean age 40.8 years) the effect of 1 ml cetirizine (5 and 10 mg/ml) given through a Wright nebuliser was compared with that of placebo in a double blind trial. The fall in FEV1 after exercise was reduced after both concentrations of cetirizine by 15.2% of baseline after 5 mg/ml and by 10.2% after 10 mg/ml, compared with 23.7% after placebo. In two patients cetirizine had no effect. In a further study cetirizine (10 mg/ml) given by inhalation displaced the geometric mean PC20 histamine 13.1 fold to the right by comparison with placebo. The reason for the difference between the effects of oral and of inhaled cetirizine on exercise asthma is not clear but may be related to differences in local concentration in the airway.
Administration, Inhalation↗
Prolonged treatment with oral and inhaled tulobuterol does not induce airways tachyphlaxis.
Beta 2-agonists have been shown to induce beta 2-adrenoceptor downregulation in vivo and in vitro. Whether this has any functional relevance remains unclear. Tulobuterol is a new synthetic beta 2-agonist with potent and prolonged bronchodilator activity when given by oral and inhaled routes. The effect of tulobuterol aerosol (400 micrograms q.i.d.) and tulobuterol tablets (2 mg b.i.d.) was studied in patients with chronic asthma and reversible airways obstruction in two separate trials. Tulobuterol produced significant bronchodilatation after the first and final dose over a 6-h period and the effects were comparable. The bronchodilator activity of tulobuterol given by inhalation and oral routes was not attenuated after 6 months of continuous treatment. There was significant improvement in symptom score and lung function measurements. Side effects, predominantly tremors, were observed at the start of treatment with tablet formulation but the incidence and severity of tremors decreased after 6 months. The changes in BP and pulse rate were not clinically significant. These results confirm the potent bronchodilator activity of tulobuterol and the lack of tachyphylaxis after prolonged treatment.
Administration, Inhalation↗
Development of a probe for the in vivo measurement of airway humidity during anaesthesia.
Airway drying can arise during long-term respiration of anaesthetic dry gases and this may have implications for the function of the airway wall. Monitoring airway humidity can identify drying trends, although previous attempts have been limited for technical reasons. The design and development of a probe to measure mid-tracheal air humidity is described. The device comprises a commercially available capacitive humidity sensor and a thermocouple. The assembled probe is catheter-like with a diameter of 9.5 mm and a length of 312 mm. Water vapour transfer response times of 1.4s (absorption) and 3.6s (desorption) were evaluated for the probe. A preliminary trial to record airway humidity in ambient air and involving six patients was performed during anaesthesia.
Adult↗
Sphincters in pulmonary veins. An anatomic study in rats.
To better understand blood flow and edema formation in the lung, anatomic evidence for venous sphincters was sought by a scanning electron microscopic investigation of vascular casts in the rat. In the first study, indentations in the casts of veins and arteries were compared. Casts of the pulmonary veins had narrow (1 to 3 microns) circumferential constrictions about every 30 microns in length (range 20 to 50 microns) and before and after accepting tributaries. Most arteries had no constriction. Infrequently, arterial narrowing occurred over long distances (greater than 30 microns). To determine if these indentations could be altered by a neural stimulus, a second study tried to cast the pulmonary microcirculation after the rats were given a blow to the head, but was unsuccessful. In a third study, the pulmonary vasculature of anesthetized rats was cleared and cast. As the resin began to harden and the animals' circulation ceased, half the animals were given a sharp blow on the head. The casts of the veins in the animals that received the blow had deeper bands than the control animals (p less than 0.001). Pulmonary veins have annular constrictions (sphincters) that are strategically located to influence blood flow. They deepen in response to the neural discharge of a head blow and should be considered in the study of neurogenic pulmonary edema.
Animals↗
Routine revascularization with resection of infected femoral pseudoaneurysms from substance abuse.
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Aneurysm↗
The effect of inhaled ouabain on bronchomotor tone and histamine responsiveness in asthmatic patients.
We have studied the effect of inhaled ouabain on resting bronchomotor tone and histamine responsiveness in eight asthmatic patients in an attempt to clarify the role of Na/K ATPase in airway reactivity. Doses ranged from 50 micrograms to 5000 micrograms and were given in a placebo controlled, double blind manner. Baseline FEV1 was recorded prior to inhalation and at intervals up to 30 min thereafter. At 30 min, a histamine provocation test was performed and results expressed as that concentration producing a 20% fall in FEV1. Maximum fall in FEV1 was not significantly different between placebo or any dose of ouabain, ranging from 4.3%-8.2% (p greater than 0.06) nor was histamine reactivity altered significantly (geometric mean range 0.17 mg-0.29 mg [p greater than 0.2]). Unlike animal studies therefore, we have been unable to demonstrate any effect of Na/K ATPase inhibition on airway reactivity in vivo.
Administration, Inhalation↗
Dose-response study of nebulised nedocromil sodium in exercise induced asthma.
Ten patients with exercise induced asthma, in whom inhaled nedocromil sodium 4 mg by metered dose inhaler attenuated the exercise fall in forced expiratory volume in one second (FEV1) by at least 40%, participated in a double blind dose response study to compare the protective effect of nedocromil sodium given 15 minutes before exercise challenge via a nebuliser (Wright) in concentrations of 0.5, 5, 10, and 20 mg/ml with that of placebo (saline). Response was assessed as the maximum fall in FEV1 after the patient had run on a treadmill for six to eight minutes. Plasma concentrations of nedocromil sodium were measured at the time of challenge. After exercise challenge the mean (SEM) maximum percentage falls in FEV1 were 30.3 (1.6) for the control run and 28.0 (4.1) after placebo. The percentage fall was attenuated by pretreatment with all concentrations of nedocromil sodium to 12.8 (2.8), 11.2 (2.1), 12.8 (2.1), and 14.1 (3.5) for the 0.5, 5, 10, and 20 mg/ml concentrations respectively (p less than 0.001). There were no significant differences between the different nedocromil concentrations. Mean plasma concentrations of nedocromil were proportional to dose. Thus concentrations of nebulised nedocromil sodium that ranged from 0.5 to 20 mg/ml gave a similar degree of protection (50-60%) against exercise induced asthma. This appears to be the maximum protection that can be achieved with nedocromil sodium and is similar to the protection obtained with 4 mg nedocromil administered by metered dose aerosol.
Adolescent↗
Effect of inhaled leukotriene C4 on cardiopulmonary function.
The changes in transcutaneous oxygen saturation (SaO2%) and airway responses to inhaled histamine and leukotriene C4 (LTC4) were examined in 10 asthmatic patients, and the effect of inhaled LTC4 (16 nmol) on cardiopulmonary hemodynamics was examined in seven nonasthmatic patients undergoing diagnostic cardiac catheterization. In asthmatic patients, LTC4 produced oxygen desaturation on two occasions. At a lower dose (2.0 nmol) LTC4 produced a marked fall in SaO2% that lasted less than 15 min and occurred in the absence of significant bronchoconstriction as measured by changes in FEV1, FEF25-75, and SGaw. At a higher cumulative dose (7 nmol), LTC4 caused prolonged oxygen desaturation with slow recovery and this was associated with significant bronchoconstriction. In contrast, histamine inhalation produced a single response with a fall in both FEV1 and SaO2% of short duration. The dose-response characteristics of LTC4 and histamine on oxygen desaturation in asthmatic patients appear to differ significantly and probably are dependent on relative sensitivities of pulmonary vascular and bronchial smooth muscle to these agonists. A single inhaled dose of LTC4 in nonasthmatic subjects produced a marked drop in PaO2 with significant increase in AaPO2, and this was associated with a mean (SEM) decrease in FEV1 of 14% (2.5) from the baseline. The mean cardiac output fell by 15% (3.4) without significant changes in blood pressure and heart rate. There was no electrocardiographic evidence of myocardial ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)
Administration, Inhalation↗
A microcomputer-based respiratory heat exchange facility for use in the diagnosis of thermally induced asthma.
Exercise-induced asthma is prevalent in many asthmatics and during the winter months can be exacerbated by cold air inhalation. A laboratory facility was required to permit early diagnosis of cold air sensitivity in these patients. This paper describes the development of a modular air conditioning system to produce a range of inhalative thermal burdens and the microcomputer interfacing to measure the rate of airway heat loss imposed. A single-stage refrigerator was built capable of cooling 150 l/min air to -25 degrees C. This was also used to generate dry ambient temperature air by rewarming the chilled air supply. An air humidifier was developed based upon natural convection and evaporation. It was capable of raising 150 l/min ambient air to 37 degrees C, 100 per cent relative humidity. In two pilot studies of 18 asthmatics it was found that the rate of respiratory heat exchange could be correlated with the magnitude of post exertional bronchoconstriction (lung dysfunction) and that exercise-induced asthma could be minimized by attenuating the rate of airway heat loss.
Adult↗
Comparison of air warming in the human airway with a thermodynamic model.
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Aged↗
Role of cooling and drying in hyperventilation induced asthma.
Respiratory heat loss has been proposed as a mechanism of exercise induced asthma. Whether the predominant stimulus is airway drying or cooling remains unclear. We have measured changes in FEV1 after isocapnic cold air hyperventilation (CAH) (-23.4 degrees (SD 0.43 degrees) C) and dry ambient air hyperventilation (AAH) (18.7 degrees (0.52 degrees)C) in seven asthmatic patients (mean age 31 (SD 9) years and baseline FEV1 3.2(0.9)1) and in seven normal subjects (age 28(6) years and FEV1 3.6(0.7)1). The inspired water content in both cases was 0.3 mg/l air. The rate of respiratory heat exchange per breath was calculated in watts (W) with microcomputer based equipment. Cold air hyperventilation caused a fall in FEV1 almost twice that of ambient air hyperventilation at each level of ventilation: CAH v AAH (% fall) 8.0 (5.1) v 3.9 (4.0) at 15 l/min, 11.6 (7.8) v 7.0 (4.4) at 30 l/min, and 20.7 (10.9) v 12.4 (6.3) at 60 l/min. Identical latent heat loss (evaporative drying) was imposed on the airway during the two challenges. Sensible heat loss (convective cooling) in cold air hyperventilation was 41 W at 15 l/min, 63 W at 30 l/min, and 114 W at 60 l/min; whereas in ambient air hyperventilation the loss was 6, 13, and 23 W respectively. It is concluded that the rate of cooling of the upper airway is the predominant stimulus in hyperventilation induced asthma.
Adult↗