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Biomedical subjects

J R Skinner

Publications and source records attributed to J R Skinner.

At least 37 records · Page 2Linked to original sources
PubMed1993

Short term correction of anaemia with recombinant human erythropoietin and reduction of cardiac output in end stage renal failure.

Children with end stage renal failure and anaemia have an increased cardiac index and often gross ventricular hypertrophy. The contribution of anaemia to these abnormalities is uncertain. Eleven children with end stage renal failure and anaemia (haemoglobin concentration < 90 g/l) were enrolled into a single blind, placebo controlled, crossover study to assess the cardiovascular effects of reversing anaemia using subcutaneous human recombinant erythropoietin (r-HuEpo). Each limb lasted 24 weeks; seven children completed both limbs of the study. Haemoglobin increased with r-HuEpo, remaining above 100 g/l for a mean of 11 weeks. Cardiac index fell as a result of a reduction in both left ventricular stroke volume and heart rate. Left ventricular end diastolic diameter also decreased. In five children left ventricular wall thickness and left ventricular mass decreased with r-HuEpo, but this failed to reach significance for the whole group. Blood pressure did not change in six normotensive children completing an r-HuEpo limb; the decrease in cardiac index was therefore balanced by an increase in peripheral vascular resistance. Three children were taking anti-hypertensive treatment at the start of the study; one required an increase, and one a decrease, in treatment during the r-HuEpo limb. Short term treatment with r-HuEpo reduces cardiac index. A longer study is needed to determine whether this will, in time, result in a significant reduction in left ventricular hypertrophy.

Anemia↗
PubMed1993

Right heart pressure determination by Doppler in infants with tricuspid regurgitation.

Doppler and direct measurements of right ventricle to right atrial pressure drop were made during cardiac catheterisation on 28 occasions in 26 infants with congenital heart disease. Age was 10 days to 12 months (median 4.5 months), and weight was 3.1 to 9.0 kg (median 4.7 kg). We measured peak velocity of tricuspid regurgitation by continuous wave Doppler, and the pressure drop was calculated using the modified Bernoulli equation (delta p = 4v2). There was a high correlation (r = 0.95) between direct and Doppler measurements. Doppler values tended to underestimate the right ventricle to right atrial pressure drop, but this was not of clinical significance (mean 2 mm Hg). The 95% confidence interval for the Doppler velocity was -0.41 to +0.26 m/sec, and was consistent across the range of pressures studied. Variability between observers was tested, by two observers performing sequential paired examinations on 16 newborn babies with tricuspid regurgitation. The coefficient of repeatability was 6.3 mm Hg (95% confidence interval 4.7 to 9.5 mm Hg) or 0.26 m/sec (0.18 to 0.50 m/sec). This method of right ventricular pressure estimation, validated previously only in older children and adults, is a reproducible and accurate technique in infants with tricuspid regurgitation.

Blood Pressure↗
PubMed1992

Pulmonary and systemic arterial pressure in hyaline membrane disease.

Systolic pulmonary arterial pressure was determined serially over the first 10 days of life in 33 babies with hyaline membrane disease by measuring the peak velocity of pansystolic tricuspid valve regurgitation, using Doppler ultrasound, and applying the Bernoulli equation. Results are presented in age groups 0-12, 13-36, 37-72, and 73-96 hours respectively. The incidence of tricuspid valve regurgitation was 92, 97, 80, and 64% (falling to 35% by day 10) compared with 53, 50, 31, and 0% in 17 healthy premature infants. In comparing healthy babies with those with hyaline membrane disease, no allowance was made for right atrial pressure. The derived 'right ventricle to right atrial (RV-RA) pressure difference', was expressed as a ratio of systemic arterial (systolic) pressure. Over the first three days, this ratio fell much faster in the healthy babies. Values were 0.78:1, 0.77:1, and 0.72:1 in babies with hyaline membrane disease and 0.87:1, 0.53:1, and 0.44:1 in healthy babies. Ductal patency was prolonged in babies with hyaline membrane disease (75% on day 4 compared with 6% in healthy babies). The incidence of bidirectional ductal flow, indicating balanced pulmonary and systemic arterial pressures, was 79, 53, 30, and 20%, and in healthy babies was 41% at 0-12 hours and zero thereafter. Pulmonary arterial pressure was then calculated by adding a right atrial pressure estimate of 5 mm Hg to the RV-RA difference when the babies were ventilated. Babies of lower gestation had lower values. The pulmonary: systemic arterial pressure ratio showed considerable temporal variability, but fell with age and was raised by high mean airway pressure and pneumothorax (through a reduction in systemic pressure), and less noticeably by carbon dioxide tension. It did not correlate significantly with other indices of disease severity. Hyaline membrane disease is associated with delayed postnatal circulatory adaptation characterized by pulmonary hypertension, systemic hypotension, and prolonged ductal patency.

Aortic Valve Insufficiency↗
PubMed1992

Central venous pressure in the ventilated neonate.

As there is no other measurement of right ventricular preload, central venous pressure (CVP) measurement provides unique and important haemodynamic information. CVP is not measured routinely in neonatology and there is a shortage of data in the ventilated neonate. CVP was measured in 62 ventilated neonates. Thirteen had respiratory disorders (28-42 weeks' gestation, birth weight 860-4390 g) and 49 had congenital heart disease (birth weight 1600-4500 g, age 0.5-30 days). Data from other case reports are also presented. In the babies with respiratory distress, a value of zero was associated with clinical evidence of hypovolaemia and negative values, common in the unventilated neonate, did not occur in those who were ventilated. Values over 7 mm Hg were found in babies with evidence of myocardial dysfunction or persistent fetal circulation but were also found with transmitted high intrathoracic pressure, such as with pneumothorax. In the babies with congenital heart disease, values mostly lay between 4 and 8 mm Hg. Values outside this range, particularly above 8 mm Hg, were usually associated with profound metabolic acidosis, suggesting circulatory failure. While the main use of CVP measurement is in trend analysis, this report suggests that single measurements can be of value, though correct interpretation will depend on the context in which they are made.

Cardiac Catheterization↗
PubMed1991

Non-invasive assessment of pulmonary arterial pressure in healthy neonates.

Doppler echocardiograms were carried out on 51 healthy babies three times during the first 72 hours of life to estimate pulmonary arterial systolic pressure by measuring regurgitant tricuspid jet velocity and applying the Bernoulli equation. Tricuspid regurgitation was detected at some stage in all preterm babies and most of those born at full term. Pulmonary arterial pressure could be measured from peak regurgitant velocity in babies with pansystolic regurgitation. The incidence of pansystolic regurgitation among 34 term babies at 0-12, 13-36, and 32-72 hours of age was 22, 27, and 19%, and in 17 preterm babies (within the same age groups) was 53, 50, and 31%, respectively. Estimates of pulmonary artery pressure in the term babies were in accord with known catheter values. Pressure fell rapidly during the first day in all 51 babies. The ratio of pulmonary:systemic arterial pressure was comparable between the two groups throughout. Ductal flow patterns mirrored the fall in this ratio with age--bidirectional flow was associated with a ratio of between 0.88:1 and 1.22:1 and high velocity left to right flow with a ratio of between 0.49:1 and 0.66:1. Both these techniques are noninvasive ways of assessing neonatal pulmonary arterial pressure.

Blood Pressure↗
PubMed1990

Correction of total anomalous pulmonary venous connection below the diaphragm.

Six infants with total anomalous pulmonary venous connection below the diaphragm had correction by modification of conventional surgical technique. Catheterization revealed the confluence of the pulmonary veins draining into a descending vein below the diaphragm. Symptoms of pulmonary venous hypertension and low cardiac output were typical. All had repair with circulatory arrest (average time, 32 minutes). Mobilization of the pulmonary veins and the descending vein is important. The descending vein was transected at the diaphragm. Its anterior surface was incised through the confluence of the pulmonary veins, thus creating an open Y incision. This large Y-shaped vein was anastomosed to the left atrium and carried obliquely to the tip of the left atrial appendage. The anastomosis was fashioned so that the long limb of the Y rotated anteriorly and superiorly to substantially enlarge the left atrium, making the total diameter of the anastomosis larger than the mitral valve orifice. This simplified the surgical repair and allowed direct suture closure of the atrial septal defect in all patients, as the left atrial size was at least doubled. No postoperative complications occurred, and the patients were discharged an average of 4.2 days postoperatively. Restudy at an average of 3.5 years revealed normal pressures and normal architecture by angiography. Use of the descending vein as an integral part of the reconstruction and enlargement of the left atrium was the major technical factor leading to a successful outcome in these patients and eliminating a patch or transposition of the atrial septum.

Anastomosis, Surgical↗
PubMed1989

Disrupted coronary artery caused by angioplasty: supportive and surgical considerations.

Of 2,859 patients having percutaneous transluminal coronary angioplasty, 201 (7%) underwent emergency coronary artery bypass grafting. Two categories of patients were reviewed. Group 1 consisted of 126 patients of 2,304 who had immediate coronary artery bypass grafting after failed elective percutaneous transluminal coronary angioplasty. Ninety-eight of these patients had angiographic evidence of occlusion of a coronary artery, and 28 had angiographic evidence of coronary artery dissection. Epicardial hemorrhage was observed at operation in 20% (25 patients). Three deaths (2.4%) occurred in group 1, and an average of 3.3 grafts was performed per patient. Group 2 comprised 75 of 555 patients who had unsuccessful attempted percutaneous transluminal coronary angioplasty during an evolving myocardial infarction and required immediate coronary artery bypass grafting. Angiography revealed coronary artery occlusion in 61 patients with dissection in 14. All group 2 patients had evidence of myocardial injury by electrocardiographic and enzymatic (myocardial-specific isoenzyme of creatine kinase) criteria. Three deaths (4%) occurred in this group, and there was an average of 3.4 grafts per patient. Percutaneous transluminal coronary angioplasty is routinely performed without surgical consultation, although an operating room and team are usually available. Supportive techniques include the intraaortic balloon pump and percutaneous cardiopulmonary bypass. In those patients with coronary artery dissection, care must be taken to reestablish the true lumen of the coronary artery. Hemopericardium should be surgically explored and broken guidewires or other foreign bodies or debris removed. From 1979 through 1986, the number of patients requiring emergency coronary artery bypass grafting after percutaneous transluminal coronary angioplasty steadily declined to less than 5%.

Angioplasty, Balloon↗
PubMed1989

Percutaneous cardiopulmonary bypass: application and indication for use.

Percutaneous cardiopulmonary bypass (CPB) was used in 22 patients: 7 patients with cardiac arrest due to acute myocardial infarction; 4 patients in cardiac arrest because of failed angioplasty; 1 patient for high-risk elective angioplasty; 1 patient with massive pulmonary emboli; 2 patients with hypothermia; 2 pediatric patients (1 with sepsis and 1 in combination with extracorporeal membrane oxygenator support); 1 patient with refractory arrhythmia; and 4 patients with trauma. Percutaneous CPB involves a modified Seldinger technique that is easily applied. All patients except those with massive trauma were resuscitated with the use of percutaneous CPB. One patient requiring a very difficult proposed angioplasty received percutaneous CPB support while triple-vessel angioplasty was performed. Percutaneous CPB appears to be beneficial in resuscitating patients with refractory cardiac arrest or other forms of circulatory collapse except trauma. Limited use for brief periods in high-risk patients having elective angioplasty might be applicable.

Angioplasty, Balloon↗
PubMed1989

Permanent left ventricular assistance for outpatients through surgical implantation of a modified intra-aortic balloon pump.

There is a large population of patients in end-stage congestive heart failure who cannot be treated by means of conventional cardiac surgery, cardiac transplantation, or chronic catecholamine infusions. In 2 such patients, we provided permanent left ventricular assistance on an outpatient basis by surgically implanting a modified intra-aortic balloon pump. A Dacron-velour graft to the common iliac artery served as a covering for the extravascular portion of the balloon's pneumatic tubing, which was stabilized by routing it through the iliac crest. The tubing was then carried ventrally to exit through a stoma just above the inguinal ligament. Before hospital discharge, each patient underwent a 5-day regimen of alternate pumping and ambulation. The patient was then permitted to go home, but returned daily as an outpatient in accordance with individual need, for approximately 6 hours of hemodynamic support. The 1st patient lived 3 months after pump insertion, and the 2nd patient for 38 days. Although the 1st patient developed a fever of unknown origin that prompted us to remove the intra-aortic balloon pump unnecessarily, there was no evidence of infection upon surgical exploration and subsequent tissue culturing; she died, rather, of intractable ventricular fibrillation, apparently consequent to her 36-hour loss of hemodynamic support. The 2nd patient also died of a cause unrelated to the presence of the pump, and on autopsy showed good evidence of healing and absence of infection. On the evidence of this pilot study, we conclude that intermittent left ventricular assistance, through periodic activation of a permanently implanted intra-aortic balloon pump during outpatient visits, warrants further study as an alternative for selected patients with end-stage heart disease, when medical and other surgical options have been exhausted.

Journal Article↗
PubMed1988

Internal mammary artery versus saphenous vein graft to the left anterior descending coronary artery: prospective randomized study with 10-year follow-up.

In 1975, 80 patients undergoing revascularization were prospectively randomized to receive either a greater saphenous vein (SV) graft (41 patients, Group 1) or a left internal mammary artery (LIMA) graft (39 patients, Group 2) to the left anterior descending coronary artery (LAD). All patients were completely revascularized. The average number of grafts per patient in both groups was 3.2. Patients were followed 10 years; follow-up was 97.5% complete. Group 1 and Group 2 were compared in regard to mortality, treadmill response, myocardial infarction, reoperation, percutaneous transluminal coronary angioplasty, and return to work. Mortality in Group 1 was 17.9% versus 7.7% in Group 2 (p less than 0.05). Treadmill studies were positive in 17 Group 1 patients and 7 Group 2 patients (p less than 0.05). Myocardial infarctions occurred in 8 patients in Group 1 versus 3 in Group 2. The number of reoperations was 2 in Group 1 versus 1 in Group 2. Percutaneous transluminal coronary angioplasty was performed in 3 patients in Group 1 and 2 in Group 2. Repeat studies revealed 76.3% patency of the SV graft to the LAD (Group 1) and 94.6% patency of the LIMA graft to the LAD (Group 2). Cardiac-related mortality in Group 1 was 12.8% at 10 years (5 patients) versus 7.7% in Group 2 (3 patients). Based on this study, the IMA is a superior conduit for bypass to the LAD.

Adult↗
PubMed1986

Reperfusion protocol and results in 738 patients with evolving myocardial infarction.

Reperfusion is an accepted therapy for evolving myocardial infarction (MI), as successful reperfusion reduces morbidity and mortality. A team approach between the cardiologists and cardiac surgeons must be applied to achieve reperfusion within a finite time from the onset of coronary thrombosis. Analysis of 738 patients grouped them by successful reperfusion in the catheterization laboratory versus the operating room. Factors that predict wall motion recovery related to the onset of clinical symptoms, time to reperfusion, coronary anatomy, and collateral network were reviewed. Comparisons were made between patients with stable versus unstable hemodynamics and successful or unsuccessful reperfusion. Of the 738 patients, the initial attempt at reperfusion was made in the catheterization laboratory with success in 331. These patients all had primarily single-vessel disease. With multiple-vessel disease identified at catheterization, 189 patients were immediately treated by surgical reperfusion. This method also was used for an additional 72 patients in whom reperfusion could not be achieved in the catheterization laboratory. Of the entire group of 738 patients, 146 (20%) could not be reperfused. Overall mortality for the 592 patients reperfused was 4.9% compared with 17% for those who could not be reperfused. Time was critical for wall motion recovery if no collaterals were demonstrated on angiography. If collaterals were present, time to reperfusion was not critical. Wall motion recovered in 90% of the patients if the endocardial anatomy on the initial angiogram was smooth. However, if the endocardial anatomy looked mottled and irregular, less than 10% of patients had recovery of wall motion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗