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W R Lynch

Publications and source records attributed to W R Lynch.

5 recordsLinked to original sources
PubMed2000

Hemodynamic effect of a low-resistance artificial lung in series with the native lungs of sheep.

BACKGROUND: An artificial lung with 1 to 6 month work life could act as a bridge to transplantation. A pumpless artificial lung has been developed. METHODS: The artificial lung was placed in series with the native lungs of adult sheep. Hemodynamics were observed, as the right ventricle generated flow through the device. Through a left thoracotomy, two 20-mm grafts were anastomosed in an end-to-side fashion to the pulmonary artery. The grafts were externalized, and directed flow through the chest wall, to the extracorporeal lung. The animals were recovered, weaned from the ventilator, and when standing, flow was diverted through the device. RESULTS: Five of 7 animals survived 24 hours with 75% to 100% of the cardiac output diverted through the device. All animals were active, with interest in food and water, and able to stand. CONCLUSIONS: The right ventricle perfused the artificial lung with 75% to 100% of the cardiac output for 24 hours. This device demonstrates the feasibility of a pumpless pulmonary assist device relying on the right ventricle for perfusion.

Animals↗
PubMed2000

Effect of rate and inspiratory flow on ventilator-induced lung injury.

BACKGROUND: We examined the effects of decreasing respiratory rate (RR) at variable inspiratory times (It) and reducing inspiratory flow on the development of ventilator-induced lung injury. METHODS: Forty sheep weighing 24.6+/-3.2 kg were ventilated for 6 hours with one of five strategies (FIO2 = 1.0, positive end-expiratory pressure = 5 cm H2O): (1) pressure-controlled ventilation (PCV), RR = 15 breaths/min, peak inspiratory pressure (PIP) = 25 cm H2O, n = 8; (2) PCV, RR = 15 breaths/min, PIP = 50 cm H2O, n = 8; (3) PCV, RR = 5 breaths/min, PIP = 50 cm H2O, It = 6 seconds, n = 8; (4) PCV, RR = 5 breaths/min, PIP = 50 cm H2O, It = 2 seconds, n = 8; and (5) limited inspiratory flow volume-controlled ventilation, RR = 5 breaths/min, pressure-limit = 50 cm H2O, flow = 15 L/min, n = 8. RESULTS: Decreasing RR at conventional flows did not reduce injury. However, limiting inspiratory flow rate (LIFR) maintained compliance and resulted in lower Qs/Qt (HiPIP = 38+/-18%, LIFR = 19+/-6%, p < 0.001), reduced histologic injury (HiPIP = 14+/-0.9, LIFR = 2.2+/-0.9, p < 0.05), decreased intra-alveolar neutrophils (HiPIP = 90+/-49, LIFR = 7.6+/-3.8,p = 0.001), and reduced wet-dry lung weight (HiPIP = 87.3+/-8.5%, LIFR = 40.8+/-17.4%,p < 0.001). CONCLUSIONS: High-pressure ventilation for 6 hours using conventional flow patterns produces severe lung injury, irrespective of RR or It. Reduction of inspiratory flow at similar PIP provides pulmonary protection.

Animals↗
PubMed1979

Hydroxyproline metabolism in two sisters with hydroxyprolinemia.

Hydroxyproline metabolism was evaluated in two sisters with hydroxyprolinemia and their mother. 33 and 21% of an oral hydroxyproline load (200 mg/kg) was excreted by the sisters, 5.4% by the mother, and 1.3% by normal subjects. Plasma and erythrocyte values in the sisters and their mother were elevated, indicating that extra- and intracellular hydroxyproline pools were increased. Analysis for urinary glycolate and oxalate (metabolic products of hydroxyproline) showed no increased excretion by the two sisters, although the mother's excretion was normal. A deficiency of hydroxyproline oxidase in the two sisters was indicated by the lack of delta 1-pyrroline-3-hydroxy-5-carboxylic acid excretion.

Adult↗
PubMedDate not supplied

A new interpretive method for impedance plethysmography.

Clinical experience revealed that Wheeler's interpretative method for impedance plethysmography studies resulted in a large number of false negative and borderline interpretations, so a new interpretative method was created using additional impedance plethysmography parameters. This study was performed to compare this new method with Wheeler's method in 21 patients with suspected deep venous thrombosis. The accuracy of each method was determined by comparing the impedance plethysmography interpretations with venography. The patients were divided into groups according to venogram results of no thrombosis, and tibial (calf) venous thrombosis. Nine of the 21 patients had no thrombosis on venogram. Wheeler's method and the new method both resulted in 56% true-negative interpretations. Twelve of the 21 patients had proximal deep venous thrombosis and/or tibial venous thrombosis on venogram. Wheeler's method resulted in 8% true-positive interpretations and 17% false-negative interpretations. Of the patients in the study, 62% had borderline interpretations. The new method resulted in 75% true-positive interpretations and no false-negatives. The new method decreased the borderline interpretations to 33%. By calculating a basal impedance difference between the patient's two legs, the new method did provide guidelines that could identify patients with borderline interpretations who would require additional testing. The new impedance plethysmography interpretative method did lower the number of borderline and false-negative interpretations, and it provided guidelines to identify patients with borderline interpretations who need further testing.

Algorithms↗