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Biomedical subjects

D T Pearson

Publications and source records attributed to D T Pearson.

33 records · Page 2Linked to original sources
PubMed1983

Incidence and prognostic importance of jaundice after cardiopulmonary bypass surgery.

In a prospective study of 248 consecutive patients undergoing cardiopulmonary bypass surgery, early postoperative "post-pump" jaundice (PPJ) developed in 49 (20%). Development of PPJ was strongly associated with a bad outcome; 25% of jaundiced patients and 1% of non-jaundiced patients died in the postoperative period. The jaundice was a conjugated hyperbilirubinaemia, and was detectable in 48 out of 49 patients by postoperative day 2. Hypotension, hypoxia, and hypothermia ("shocked liver") were not associated with the development of PPJ, nor was evidence of haemolysis or heart-failure. Although PPJ was significantly associated with multiple valve replacement, higher transfusion requirements, and longer cardiopulmonary bypass time, it also occurred in patients undergoing uncomplicated operations. It is suggested that PPJ is caused by a defect in hepatic excretion of bilirubin.

Bilirubin↗
PubMed1981

Reduction of systemic vascular resistance by competitive alpha adrenergic blockage with thymoxamine after cardiopulmonary bypass for cardiac operations.

Fifteen patients with evidence of excessive systemic vasoconstriction following cardiac operations were studied. Serial hemodynamic measurements were made before and during infusion of thymoxamine, a competitive alpha adrenergic blocking drug. Thymoxamine resulted in a full in systemic resistance together with a rise in cardiac index without reflex tachycardia. When thymoxamine was infused at a rate of 1 mg . kg-1, the desired effect was achieved without sudden profound falls in arterial pressure and there were no significant side effects. During the first few hours after bypass, skin temperature measurements do not give an adequate indication of the circulatory state. Measurement of mixed venous oxygen saturation is a most useful, simple method of monitoring the acute effects of treatment during this period.

Adult↗
PubMed1978

An ultrasonic analysis of the comparative efficiency of various cardiotomy reservoirs and micropore blood filters.

The ability of 12 commercially available cardiotomy reservoirs to remove bubbles from aspirated blood was investigated by means of a simulated cardiopulmonary bypass circuit and an ultrasonic microbubble detector. Performance varied considerably. The number of gaseous microemboli remaining after passage of blood through the reservoir was reduced by (a) holding the blood in the reservoir, (b) reducing the volume of air mixed with the aspirated blood, and (c) using a reservoir that did not induce turbulence and that contained integral micropore filtration material. Further micropore filtration of the blood after passage through the cardiotomy reservoir was beneficial, and significantly more bubbles were extracted when the microfilter was sited below the reservoir than when it was placed in the arterial line.

Cardiopulmonary Bypass↗
PubMed1977

Prevention of venous blood gas embolism with blood microfilters.

The efficacy of blood microfilters in removal of the gaseous emboli produced during the warming of blood for transfusion is demonstrated experimentally. It is suggested that when blood microfilters are used they should be placed distal to any blood warming device.

Blood Transfusion↗
PubMed1970

Direct current shock and antidysrhythmic drugs.

A review is given of 457 episodes of atrial fibrillation that occurred in 318 patients and were treated by DC shock. Antidysrhythmic drugs, such as quinidine, procainamide, and propranolol, given singly or in combination, were used concomitantly in 389 instances, and DC shock alone was given in 68 instances. The combined effects of quinidine and DC shock, and of procainamide and DC shock were studied in the experimental animal.Combined DC shock and drug therapy gave a higher conversion rate than DC shock alone, and a statistically significant difference was found in respect of the group of patients receiving procainamide and propranolol together (p<0.01). Antidysrhythmic drugs failed on the whole to reduce the incidence of DC shock-induced dysrhythmias. However, the incidence of certain digitalis and DC shock-induced dysrhythmias was significantly less when propranolol and procainamide were given as pretreatment than when procainamide or quinidine was given alone (p<0.01). In animal experiments, quinidine had no protective action against digitalis and DC shock-induced ectopic tachycardias. Clinical and experimental observations suggest that the cardiotoxicity of these drugs may be enhanced by DC shock. Immediate or delayed post-shock rhythm disorders can be drug related and, therefore, great caution should be exercised in the use of antidysrhythmic drugs in conjunction with DC shock therapy.

Animals↗
PubMedDate not supplied

A clinical evaluation of the gas transfer characteristics and gaseous microemboli production of two bubble oxygenators.

The gaseous microemboli (GME) production and gas transfer characteristics of two series of bubble oxygenators (Harvey H-1500 and Bentley BOS-10) were evaluated during clinical perfusion in 33 adult patients during open heart surgery for acquired valvular and ischaemic heart disease. For each oxygenator series, patients were divided into two groups, depending upon the method of measurement (intermittent or continuous) of the arterial PO2(PaO2). Using the data available, the perfusionist altered the gas:blood flow ratio in an attempt to maintain the PaO2 within the normal range. In the first group (I = intermittent), where PaO2 data were available only intermittently, the PaO2 values were well above normal, and large numbers of GME were detected in the arterial blood. In the second group (C = continuous), where the PaO2 data were available continuously, there was significantly better control of the PaO2 (P less than 0.001 and P less than 0.01 for the H-1500 and BOS-10, respectively) and significantly fewer GME (P less than 0.01 and P less than 0.05 for the H-1500 and BOS-10, respectively). The Bentley BOS-10 oxygenator used a lower gas:blood flow ratio to achieve physiological levels (range 9 to 13 kPa at 37 degrees C) of PaO2 than did the Harvey H-1500 oxygenator, but there was no difference in the number of GME detected. The lower gas:blood flow ratios for the BOS-10 oxygenators in group C resulted in significantly higher PaCO2 values well outside the physiological range (4 to 6 kPa at 37 degrees C) during the rewarming phase (mean PaCO2 = 7.6 +/- 0.8 kPa) of cardiopulmonary bypass than did the H-1500 oxygenator (mean PaCO2 = 6.3 +/- 0.7 kPa). Mean values for the PaCO2 for both oxygenators during other phases of bypass (cooling and hypothermia) were within the physiological range. If the CO2 retention was corrected by increasing the gas:blood flow ratio the PaO2 values and GME counts became elevated.

Adult↗