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Biomedical subjects

G D Jay

Publications and source records attributed to G D Jay.

35 records · Page 2Linked to original sources
PubMed1996

Continuous, noninvasive measurement of pulsus paradoxus in patients with acute asthma.

OBJECTIVE: To evaluate a continuous, noninvasive measurement technique for pulsus paradoxus (PP) as an objective asthma severity indicator. DESIGN: Prospective, masked assessment of the relationship between PP, peak expiratory flow rate, oxygen saturation, clinical scoring, and admission decisions. SETTING: An urban pediatric emergency department. PATIENTS: Children with acute asthma. INTERVENTIONS: Standardized treatment per National Heart, Lung, and Blood Institute guidelines. MAIN OUTCOME MEASURES: Peak expiratory flow rate, oxygen saturation, pulmonary index score, and masked disposition decision. RESULTS: Significant positive correlations existed between PP and the pulmonary index score at the initial evaluation (r = 0.44; P < .001) and after 30 minutes (r = 0.51; P < .001) and 60 minutes (r = 0.45; P < .001). Significant negative correlations existed between PP and the percent predicted peak expiratory flow rate (r = -0.31; P = .01) and the oxygen saturation (r = -0.30; P = .02). The mean PP was significantly greater in patients who were admitted for further treatment at all time points (P = .003 or P = .002). At 30 minutes after presentation, a PP greater than 15 mm Hg predicted admission for further treatment or relapse; the sensitivity was 0.42, the specificity was 0.89, and the likelihood ratio was 3.86. CONCLUSIONS: Our measurement technique for PP is a useful objective indicator of the severity of asthma. Pulsus paradoxus correlates with clinical score, peak expiratory flow rate, and oxygen saturation. Furthermore, an elevated PP is associated with the decision to admit a patient for further treatment. These results suggest that this technique may represent a useful research tool for the assessment of acute, severe asthma. Further development of the technology may allow for a clinical application.

Acute Disease↗
PubMed1995

Use of infrared thermometry to measure lavage and intravenous fluid temperature.

A study was conducted to determine the accuracy of tympanic thermometers for measuring the temperature of warmed fluids in fluid bags and in tubing at the delivery site (ie, beside the intravenous [IV] catheter). One-liter 0.9% saline bags were warmed in a microwave oven. A thermocouple electronic temperature probe was then used to measure the reference temperature. The probe was inserted into each bag and bathed in the fluid. Temperature changes were recorded simultaneously over a 20-minute period using the probe and a First Temp Tympanic Thermometer (Intelligent Medical Systems, Inc, Carlsbad, CA). The warmed fluid was then allowed to run through microdrip IV tubing. Temperature of the effluent was measured in the tubing using the tympanic thermometer externally and the probe internally at the same point. The two measures were compared using linear regression and Student's t tests. Overall, the correlation between the two probes was r = 0.99 for both the fluid bags and the IV tubing. The overall mean differences were small, 0.7 degrees C and 1.2 degrees C for the bags and tubing, respectively, but they were statistically different (P > .05). Data were analyzed in three temperature ranges: < 36 degrees C, 36 degrees C to 41 degrees C, and 41 degrees C. Again, small differences were found on the order of 1 degree C. It was concluded that infrared thermometry is an accurate method for measuring the initial and delivery temperature of warmed fluids. Although tympanic thermometer measurements were statistically different from reference readings in certain temperature ranges, these differences were small and not clinically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation Studies as Topic↗
PubMed1995

Portable hyperbaric oxygen therapy in the emergency department with the modified Gamow bag.

STUDY OBJECTIVE: To compare oxygen administration by means of an inflatable portable hyperbaric chamber with that through a nonrebreather mask for the elimination of carboxyhemoglobin (COHb). DESIGN: Double-crossover prospective analysis. SETTING: University emergency department, Level I trauma center. PARTICIPANTS: Twelve healthy paid adult volunteers, all smokers. INTERVENTIONS: Each subject smoked five cigarettes within 60 minutes. COHb levels were measured before and after smoking by means of cooximetry. Subjects then breathed hyperbaric and normobaric oxygen in separate trials for 40 minutes. Normobaric oxygen was administered through a nonrebreather face mask at 15 L/minute outside the Gamow bag. Hyperbaric oxygen was delivered inside the Gamow bag with a demand valve regulator mask at a pressure of 1.58 atmospheres absolute pressure (8.5 psi). Venous blood (.5 mL) was sampled every 5 minutes. The specimens were iced and assayed for COHb in triplicate. RESULTS: A significant increase in the elimination of COHb was observed for each subject in the Gamow bag (P < .05, repeated-measures ANOVA). The average half-life for COHb elimination was 27.5 +/- 1.08 minutes (mean +/- SE) (n = 10). IV access failure occurred in two patients, with incomplete data as a result. CONCLUSION: The modified Gamow bag eliminated COHb more quickly than did nonrebreather mask oxygen and proved simple to operate and maintain. No complications were noted for any of the subjects. One subject experienced claustrophobia, but it abated after the bag was inflated.

Adult↗
PubMed1995

Continuous noninvasive determination of pulsus paradoxus: a pilot study.

OBJECTIVE: To evaluate two methods of continuous, noninvasive monitoring of pulsus paradoxus (PP). METHODS: A single-subject, nonblind assessment was conducted of the ability of noninvasive monitoring techniques to measure experimentally induced PP. Variable degrees of PP were induced in a healthy adult breathing through a one-way valve to which a series of external airway resistances were added. Intra-arterial pressure (IAP), finger arterial blood pressure (FINAP), pulse oximeter pulse waveform, and chest wall motion were continuously recorded. For each resistance, PP was calculated from the IAP (PPIAP) and the FINAP (PPFINAP) recordings. PP was measured manually (PPmanual) in the opposite arm. The percentage pulse waveform decrease on inspiration (%PWDpleth) was derived from the oximeter pulse waveform. These measurements were compared with the PPIAP. Bias was assessed as the mean difference between PP measures. RESULTS: PPFINAP was highly correlated with PPIAP (r = 0.96; 95% CI 0.93 to 0.98; p < 0.0001). There was a weak correlation between PPmanual and PPIAP (r = 0.27; 95% CI -0.05 to 0.55; p = 0.0963). The %PWDpleth correlated with PPIAP (r = 0.59, 95% CI 0.32 to 0.78; p = 0.0002). Bias was -1.515 +/- 5.6 mm Hg between PPIAP and PPFINAP; and -4.508 +/- 23.4 mm Hg between PPIAP and PPmanual. CONCLUSION: An accurate and continuous PP can be measured noninvasively using a FINAP monitor. This method has much better agreement with IAP measurements than do manual measurements. The qualitative information provided by the oximeter pulse waveform is less accurate than that provided by the FINAP monitor, but is a potentially useful screening tool for detection of significant PP.

Adult↗
PubMed1994

Pulse oximetry is accurate in acute anemia from hemorrhage.

HYPOTHESIS: Pulse oximetry is an accurate, noninvasive assay of oxygen saturation percentage (SaO2) in acutely severe anemia (less than 5 g/dL). DESIGN: A paired comparison of SaO2 by pulse oximetry (SpO2) and arterial blood gas analysis (SaO2) in patients with either acute gastrointestinal bleeding or blunt trauma with hematocrit of less than 20%. SETTING: An academic emergency department in a tertiary referral hospital with a Level I trauma center. PARTICIPANTS: Seventeen nonhypoxic patients were identified with initial hematocrit of less than 20% over a 9-month period. MEASUREMENTS AND MAIN RESULTS: Determination of SaO2 by pulse oximetry and arterial blood analysis was not statistically significantly different (P < .05) over a range of hemoglobin levels from 2.3 to 8.7 g/dL. The observed mean difference between SpO2 and SaO2 was 0.53 +/- 0.23% (mean +/- SEM; n = 17). The 95% confidence interval associated with this difference score ranged from 0.044 to 1.014. CONCLUSION: Despite reports that pulse oximetry is inaccurate below a hemoglobin concentration of 5 g/dL, our study suggested that this technology is accurate and reliable at 2.3 g/dL for nonhypoxic SaO2 values (SaO2 of more than 93%). The anemic endpoint where pulse oximetry either becomes inaccurate or simply fails to work has not been determined. Pulse oximetry overestimates SaO2 on average by 0.53% over a range of hemoglobin concentrations from 2.3 to 8.7 g/dL.

Acute Disease↗
PubMed1992

Altered surface character of stretched condom latex.

A new type of imperfection in condom latex, present during moderate stretching, was observed by low magnification scanning electron microscopy. The normally smooth surface of relaxed natural latex was transformed into an accordion-like arrangement of ripples in addition to tears. A corollary experiment with Alcian blue dye placed into both stretched and unstretched condoms leaked no dye. These surface features are consistent with latex acting as a molecular barrier. The tears may represent areas of lowered mechanical resistance and raise questions concerning quality control.

Contraceptive Devices, Male↗
PubMed1992

Evaluation of pulse oximetry in anemia from hemoglobin-H disease.

A patient with hemoglobin-H (Hb-H) disease developed an acute hemolytic crisis after treatment with trimethoprim and sulfamethoxazole. Despite her poor clinical condition and profound anemia (Hb, 2.7 g/dL), pulse oximetry continued to demonstrate a high O2 saturation percentage. Manipulation of Beer's law shows that anemia theoretically should not affect pulse oximetry values. The literature describes the effects of dyshemoglobinopathies such as carboxyhemoglobinemia and methemoglobinemia on O2 saturation percentage measured by pulse oximetry, but the effect of genetic hemoglobinopathies on pulse oximetry values is largely unreported. Because most hemoglobinopathies do not significantly change the protein-heme electronic interaction, the values of O2 saturation percentage determined through pulse oximetry should remain clinically valid. Hb-H is an exception to this generalization; as in patients with carboxyhemoglobinemia, pulse oximetry measurements showing high O2 saturation percentage do not correspond to high levels of oxygen available for delivery to tissues.

Adult↗
PubMed1992

Characterization of a bovine synovial fluid lubricating factor. I. Chemical, surface activity and lubricating properties.

A lubricating glycoprotein (PSLF) with an apparent molecular weight of 280 kDa was purified from bovine synovial fluid by anion exchange, molecular sieve chromatography, and density gradient centrifugation. Lubrication was measured under boundary conditions as lowering of the coefficient of friction (mu) between oscillating natural latex and polished glass. Lubricating ability was first observed at a concentration of 200 micrograms/ml and became maximal at 260 micrograms/ml. Hydrophobic interfacial tension measurements indicated that at the former concentration, monolayers of PSLF formed. Sugar digestions showed that lubricating ability depends upon the terminal galactose of the molecule. PSLF is similar if not identical to lubricin. It is proposed that a repulsive hydration force is the molecular mechanism for lubricating activity.

Amino Acids↗
PubMed1992

Characterization of a bovine synovial fluid lubricating factor. II. Comparison with purified ocular and salivary mucin.

Boundary lubricating activity and biochemical characteristics of purified lubricating factor from bovine synovial fluid (PSLF) were compared to those of mucinous glycoprotein from human submandibular saliva and stimulated tears. Mammalian synovial fluid and saliva contain mucinous glycoproteins which reduce the coefficient of friction (mu) in a bearing of latex:glass which isolates boundary lubrication. In contrast, mucin secreted by the lacrimal gland did not lubricate. Cleveland plotting showed that these species are not identical.

Animals↗
PubMed1992

Characterization of a bovine synovial fluid lubricating factor. III. The interaction with hyaluronic acid.

Although hyaluronate is not a boundary lubricant in cartilaginous and latex:glass bearings, a distinct interaction with purified synovial lubricating factor (PSLF) was demonstrated by three means: 1) enhancement of lubricating ability in an artificial test system; 2) viscometry; 3) electron microscopy. The interaction was of a physical rather than a specific chemical type; it varied with the degree of purification of PSLF and of hyaluronate. The interaction accounts for retention of the relatively small PSLF molecule (approximately 280 kDa) with the synovial mucin on a 0.22 microns filter. The data provide evidence that hyaluronate and PSLF act synergistically in the boundary lubricating activity of animal joints.

Animals↗
PubMed1990

Silver staining of extensively glycosylated proteins on sodium dodecyl sulfate-polyacrylamide gels: enhancement by carbohydrate-binding dyes.

Two methods are described for detecting less than 1 microgram of highly glycosylated proteins, such as mucins, on sodium dodecyl sulfate-polyacrylamide gels. They combine commonly employed periodic acid-Schiff (PAS) and Alcian blue dyes with silver stain. Carbohydrate prestaining renders mucins more cationic and favors greater complexation with ionic silver. Comparisons of different mucin samples stained either with PAS-silver or alcian blue-silver indicate differential staining between the two techniques. Such differences may, in part, be due to an affinity of Alcian blue for sulfated glycoproteins. These two staining protocols when used in conjunction with silver staining alone are particularly valuable for assessing sample purity and for detecting contaminating proteins during mucin purification protocols.

Alcian Blue↗
PubMed1989

Clinical and chemical characterization of an adventitial popliteal cyst.

We present further evidence that adventitial cysts of the popliteal artery are ganglions, based on studies of a lesion found in a 51-year-old man. The cyst was located entirely within the adventitia, lacked a cellular lining, and did not communicate with either the arterial lumen or the synovial space. The contents were gel-like and composed of 1.64 gm of hyaluronic acid and 0.20 gm of protein per dl. This material did not possess boundary-lubricating ability in a test system that slides natural latex rubber against glass. The histologic appearance, chemical composition, and absence of lubricating ability more closely resemble the characteristics of ganglions. These findings suggest that the cyst was not synovial but rather ganglionic in origin.

Exudates and Transudates↗