Biomedical subjects

W H Noble

Publications and source records attributed to W H Noble.

At least 55 records · Page 3Linked to original sources

PubMed1976

A histologic comparison of effects of electrosurgical resection using different electrodes.

Electrosurgery is a helpful adjunct to restorative dentistry, yet there often is damage to underlying connective tissue. In this study, small loop electrodes demonstrated a wider area of coagulation necrosis than was found with needle electrodes. In all instances, coagulation necrosis as a result of heat was noted. To help minimize tissue damage, very fine wire electrodes should be used, and entry into deep tissue layers should be avoided.

Electrodes↗

PubMed1975

Early changes in lung water after haemorrhagic shock in pigs and dogs.

This study has demonstrated a 34 per cent rise in lung water after shock and retransfusion of blood. This extra lung water was associated with increased pulmonary artery pressure, increased plumonary vascular resistance and reduced myocardial performance. These findings occurred despite the failure of arterial pressure to return to normal after retransfusion blood. Although this increased lung water is less than anything which can be detected clinically it may represent the beginnings of the shock lung syndrome as oedema progresses over period of weeks. A reasonable approach to the problem should include attempts to reduce the elevated plumonary vascular resistance. NaHCO3 should be infused before or during administration of the first bottle of blood in an attempt to improve myocardial function and reduce pulmonary vascular resistance. Fluids should not be infused simply to return arterial pressures in the pulmonary vascular bed. Pulmonary artery and wedge pressure monitoring with Swan Ganz catheters may improve the management of shock patients.

Animals↗

PubMed1975

Use of aspirin in haemorrhagic shock.

Haemorrhagic shock was induced in two similar groups of dogs for two hours. One group received aspirin before shock and the other group served as a control. When blood was retransfused the PVR which was markedly elevated during shock returned to pre-shock value in the aspirin group but was elevated 100 per cent in the control group, despite correction of a cidosis. Aspirin reduces collagen-induced platelet aggregation and thereby inhibits the formation of platelet micro-emboli without affecting the coagulationfactors. This effect of aspirin is thought to be responsible for the lowering of the elevated PVR to pre-shock values in the aspirin group following retransfusion. Because of the metabolic acidosis associated with the shock state, concurrent administration of sodium bicarbonate is recommended when transfusing shocked patients with blood. A clinical trial of aspirin in early treatment of shocked patients as well as for prophylaxis in high risk situations is justified.

Animals↗

PubMed1975

The effects of continuous positive pressure ventilation on pulmonary oedema, gas exchange and lung mechanics.

The effect of continuous positive pressure ventilation was studied in 23 dogs in whom pulmonary oedema was induced by rapid intravenous infusion of dextran 40. CPPV slowed but did not prevent the formation of oedema. CPPV prevented or reversed the formation of liver-like areas in the dependent lobes, maintaining the oedematous lung compliant and aerated. This led to a reduction of shunt and an increase in PaO2. The use of CPPV decreased cardiac output and body oxygen consumption. Mixed venous oxygen tension was higher in dogs ventilated by CPPV and these dogs tolerated fulminant frothy oedema without distress.

Animals↗

PubMed1975

Radiological changes in controlled hypervolaemic pulmonary oedema in dogs.

Chest radiographs taken under ideal conditions and reviewed by a radiologist experienced in looking for pulmonary oedema are an accurate technique for detecting early oedema, differentiating between congestion and oedema, monitoring the increases in oedema up to the stage of alveolar flooding and in determining the effects of CPPV on an oedematous lung. However, ideal conditions do not exist in the I.C.U. Our radiologist had the advantage of a fast exposure, a normal film for comparison in the sequence and only one lesion, conditions unlikely to occur in the I.C.U. It becomes apparent that it is important to obtain the best possible image in these complicated patients. Films in the erect position, for vascular distribution, as well as fast exposures with a high MAS factor give the sharp detail required to best assess lung changes. Serial studies of the chest are a requirement of the I.C.U. patient and it is helpful if comparable films are obtained by using a fixed target-to-film distance in association with the short exposure factors. If this care is taken, chest radiographs are the most accurate non-invasive technique for detecting pulmonary oedema.

Animals↗

PubMed1975

Use of chloroquine in shock.

One group of dogs received single doses of intramuscular chloroquine and another group served as a control. The dogs were subjected to haemorrhagic shock and then retransfused with their own blood after two hours of shock. The chloroquine-treated dogs had normal PA pressures after correction of acidosis and significantly smaller increases in the pulmonary vascular resistance. The results are similar but less marked than those obtained with aspirin. Chloroquine inhibited in vitro platelet aggregation by 50% and was not associated with any increased bleeding. This may be an advantage when used in patients with multiple trauma or increased bleeding tendency.

Animals↗

PubMed1975

Anteroposterior position of "Myo-Monitor centric".

Nine patients had interocclusal recordings made at "Myo-Monitor centric", centric occlusion, and centric relation. With the use of centric relation as a reference point, the anteroposterior distances from centric relation to centric occlusion and Myo-Monitor centric were measured. In addition, the variations in Myo-Monitor centric were analyzed by making repeated interocclusal records on the same patient. Results showed that, within the limits of this study, Myo-Monitor centric was anterior to centric relation but was slightly retrusive to centric occlusion. Also, Myo-Monitor centric recordings were variable from the left and right sides of the same patient and varied on the same side of the same patient.

Adult↗

PubMed1975

Lung mechanics in hypervolemic pulmonary edema.

Extravascular thermal volume of the lung (ETVL) is a double indicator dilution technique of use in measuring pulmonary edema. ETVL and lung mechanics measurements were followed to find a less invasive monitor of pulmonary edema than the double indicator dilution technique. Pulmonary edema was induced by overloading the dogs' circulation with dextran. Phases of overload were defined on the basis of a previous electron microscopic study (Noble et al., Can. Anesthetists Soc. J. 21:275, 1974) of lung biopsies relating anatomic changes to physiologic measurements of ETVL and central blood volume (CBV). Congestion occurred when CBV was elevated and ETVL was not, interstitial edema when ETVL was elevated but smaller than 60% above control and alveolar edema when ETVL greater than 85% above control. Once the dogs were in alveolar edema, they were mechanically ventilated with 4, 8, 12, and 16 cmH2O end-tidal pressure (CPPV). Mean functional residual capacity (FRC) for all 15 dogs did not change up to the time CPPV was applied. Pulmonary resistance did not rise until alveolar edema was present. Once in pulmonary edema, lung compliance always fell as lung water increased. In individual dogs, the compliance fall was directly proportional to the rising lung water. However, the variations in slope and beginning point among dogs made it difficult to predict the amount of lung water from dynamic compliance values. PaO2 fell markedly in alveolar edema as a result of a widened A-a gradient. CPPV did not decrease lung water but did increase FRC and PaO2.

Animals↗

PubMed1974