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Biomedical subjects

I M Ledingham

Publications and source records attributed to I M Ledingham.

At least 73 records · Page 4Linked to original sources
PubMed1981

Aspirin inhibits the early myocardial release of thromboxane B2 and ventricular ectopic activity following acute coronary artery occlusion in dogs.

Acute coronary artery occlusion in anaesthetized open-chest greyhounds led to early release of thromboxane B2 (TxB2) into venous blood draining the ischaemic region. No release occurred from the remainder of the left ventricular wall (coronary sinus sampling). TxB2 release and ventricular ectopic activity were positively correlated (r = 0.863) 2 min post-occlusion. Aspirin (3 mg/kg i.v.) suppressed both local TxB2 release and ectopic activity and prevented ventricular fibrillation. It is suggested that TxB2 release is a factor contributing to early post-infarction arrhythmias.

Animals↗
PubMed1981

Late respiratory sequelae of blunt chest injury: a preliminary report.

Eighty-six survivors of blunt chest injury were assessed for pre- and post-injury respiratory symptoms using a standardised questionnaire. A comparison was made between observed and expected symptom prevalence and lung function. Respiratory symptom prevalence after injury was greater than expected, 23 survivors (27%) claiming a persistent productive cough, 18 (21%) persistent wheezing, and 22 (26%) grade 2 dyspnoea. After injury persistent productive cough (p less than 0.05) and occasional wheezing (p less than 0.01) were more common among smokers and ex-smokers when compared with non-smokers. Mean forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were not statistically different from expected values. We concluded that respiratory sequelae of blunt chest injury are common and that smokers and ex-smokers are at particular risk.

Adult↗
PubMed1980

Treatment of accidental hypothermia: a prospective clinical study.

A 15-year prospective study was carried out of 44 patients with accidental hypothermia (mean age 60 years) admitted to an intensive therapy unit. The lowest core temperature recorded in each patient ranged from 20.0 to 34.3 degrees C. The precipitating factors were poisoning (by drugs, alcohol, or coal gas) in 25 cases and various illnesses in 19. Rewarming was achieved in 42 patients by applying a radiant heat cradle over the torso, and in two patients by mediastinal irrigation with warmed fluids. Twelve patients died, but only two during the period of rewarming. Thus rewarming may be consistently and safely achieved irrespective of the cause of hypothermia, and normal body temperature may be regained as rapidly as is compatible with adequate tissue perfusion and oxygenation. Surface rewarming of the torso is perhaps the simplest technique available, but internal rewarming procedures may be desirable or essential in the presence of, for example, profound hypothermia, severe hypotension, or ventricular fibrillation. Mortality was attributable to underlying factors or disease and not to hypothermia.

Adult↗
PubMed1980

The effect of hypovolaemia on colonic blood flow in the dog.

The effects of a minor degree of hypovolaemia on colonic blood flow and on systemic haemodynamics have been studied in nine greyhound dogs. A loss in blood volume of 10 per cent over 20 min produced no change in blood pressure and only a 7 per cent rise in heart rate. Cardiac output, however, fell by 26 per cent and central venous pressure also fell significantly. Colonic blood flow fell by 28 per cent and oxygen availability by 29 per cent. All these changes were statistically highly significant. Retransfusion of shed blood resulted in a slow and incomplete return to pre-bleed status. Since colonic blood flow and oxygen availability during and after surgery may be important for colonic healing, it is suggested that even the slightest degree of hypovolaemia should be avoided in cases involving colonic anastomosis. Systemic blood pressure may be an inadequate index of the need for transfusion in these cases.

Animals↗
PubMed1980

The use of inotropic drugs in myocardial contusion: 2 case reports.

Myocardial contusion is a common complication of blunt chest injury. Severe heart failure and shock may result. The haemodynamic consequences of myocardial contusion in two patients are described; both received inotropic agents. In the first patient dobutamine was successful in improving myocardial function; dopamine had similar effects on the heart. In the second patient dopamine, preferred for its renal effects, produced a short-term improvement in myocardial function. The rational use of pharmacological agents in this condition demands precise understanding of the underlying haemodynamic disturbances.

Adult↗
PubMed1980

Fine screen filtration of banked blood: effect on red cell survival.

Two fine screen mesh microfilters and the Baxter blood administration set commonly used in U.K. hospitals were compared for their effect on the red cell survival of transfused stored autologous blood in six healthy males. The effect of the filtered transfusions on pulmonary gas exchange and on blood coagulation was measured. No significant difference was found between either microfileter and the Baxter giving-set for the red cell survival of transfused blood. Pulmonary gas exchange and coagulation were unaffected by transfusion of one unit of whole blood. Post-transfusion bilirubin concentrations were significantly less with one of the microfilters compared with the Baxter giving-set, possibly because of trapping of effete red cells within the filter. An unsuspected finding was the effect of transfusion in increasing the peripheral blood neutrophil count.

Adult↗
PubMed1980

Colon blood flow in the dog: effects of changes in arterial carbon dioxide tension.

A new method for measuring blood flow in the colon using a 133Xenon clearance technique has been developed in the greyhound. Values for 133Xe tissue blood partition coefficient for colon have been established. The mean basal colon blood flow in 35 animals was 39.8 cm3.min-1.100g-1 with a coefficient of variation for repeat measurements of 8.7%. Hypercapnia produced a significant rise in colon blood flow to a mean maximum level of 62.2 cm3.min-1.100g-1 and hypocapnia a significant fall to a mean level of 27.9 cm3.min-1.100g-1. For arterial carbon dioxide tension (PCO2) values between 2 and 12 kPa (15 and 90 mmHg) there was a straight line relationship between colon blood flow and arterial PCO2. When hypercapnia was prolonged for 75 min, the initial rise in colon blood flow was only partially sustained, while prolonged hypocapnia for a similar period resulted in sustained reduction in flow. Mean resting colon oxygen consumption in 35 animals was 1.17 cm3.min-1.100g-1 and this was not significantly affected by hypocapnia. Hypercapnia to arterial PCO2 levels between 8 and 14 kPa (60 and 105 mmHg), however, produced a significant rise in colon oxygen consumption. Since changes in colon blood flow during and after surgery may affect healing of colonic anastomoses, these results may be relevant when considering anaesthetic techniques for patients undergoing colon resection.

Animals↗
PubMed1980

Survial from acute renal failure with and without multiple organ dysfunction.

A 10-year retrospective analysis has been carried out of 114 patients dialysed for acute renal failure. Fifty-eight patients, predominantly suffering from multiple organ failure, required treatment in an Intensive Therapy Unit (ITU); 56 less severely ill patients were treated in a Renal Unit. Overall survival in the former group was 36% and in the latter group 63%. In the first 5 years of the study, survival in the ITU patients was 31% and in the second 5 years, was 38% in spite of a trend towards increased severity of illness. These results challenge the view that haemodialysis is rarely worth-while in patients with multiple organ failure, and suggest that current management techniques have improved prognosis. The most important adverse factors continue to be old age, sepsis and gastrointestinal disease.

Acute Kidney Injury↗
PubMed1979

Dural dimpling in the dog.

Indentation of the dura has been proposed as the cause of subatmospheric pressure in the extradural space, but has never been demonstrated directly in humans. In this study, radiographs have been produced showing dimpling of the dura by a needle tip lying in the extradural space in the dog. Pressure tracings demonstrate that advancement of the needle tip produces a progressive decrease in extradural pressure, and observations made using an image intensifier have confirmed that the pressure changes are proportional to the degree of dural indentation.

Anesthesia, Epidural↗
PubMed1978

Prospective study of the treatment of septic shock.

A study of 113 patients with septic shock admitted to an intensive therapy unit (I.T.U.) during a 3-year period showed that a significant reduction in mortality was achieved after the introduction of a treatment programme which included early intermittent positive-pressure ventilation and aggressive surgery in addition to conventional management with fluids, oxygen, and antibiotics. Vasoactive drugs played an important but not essential role in therapy.

Adult↗
PubMed1978

Movement of the critically ill within hospital.

Critically ill patients can be safely moved within hospital using a mobile intensive care unit (MICU). The MICU allows the critically ill to benefit from specialised investigation and treatment they might otherwise be denied. The MICU in use at the Western Infirmary, Glasgow is described and its merits outline in the light of clinical experience gained over a twelve month period.

Adult↗