PubMed Health⌕ Search

Biomedical subjects

J C Pollock

Publications and source records attributed to J C Pollock.

At least 37 records · Page 2Linked to original sources
PubMed1991

Transcutaneous iodine absorption in infants undergoing cardiac operation.

Povidone-iodine is an effective antiseptic, but its topical use has been associated with a number of adverse reactions in burn patients and in neonates as a result of transcutaneous absorption. In particular, high plasma iodine concentrations are known to cause renal failure, metabolic acidosis, and thyroid suppression. Because of the permeable nature of the skin in small infants and the large areas cleaned before cardiac operations, it is possible that significant transcutaneous iodine absorption might occur in this situation. We have studied 17 infants, less than 3 months of age, who were undergoing closed cardiac or thoracic procedures. After povidone-iodine skin preparation in 15 (covering 20% to 30% of body surface area), plasma total iodine concentrations rose fourfold (range, 160% to 1,440%). This increase was significantly different from the preoperative level at 6, 12, 18, and 24 hours. There was no increase in plasma iodine concentration in 2 patients who were not exposed to povidone-iodine or any other iodine-containing compound. We discuss the implications for a topical antisepsis policy in infants.

Body Surface Area↗
PubMed1991

Transoesophageal echocardiographic assessment of primum, secundum and sinus venosus atrial septal defects.

We compared the ability of transthoracic and transoesophageal echocardiography to determine the presence and site of an atrial septal defect and associated anomalous pulmonary venous connexions in 13 school age children (aged 5 to 15 years) and 12 adults (aged 25 to 68 years). Transthoracic echocardiography detected atrial septal defects in 12 children and 6 adults. Transoesophageal echocardiography confirmed the position of 16 (13 secundum, 3 primum) of these 18 defects but altered the diagnosis from a secundum defect to a sinus venosus defect in one and from a sinus venosus defect to a high secundum defect in another. In addition to these 18, transoesophageal echocardiography diagnosed a defect in 5 adults (3 secundum and 2 sinus venosus defects) and 1 child (secundum defect). In an adult with inconclusive transthoracic findings, transoesophageal echocardiography enabled clear visualisation of the atrial septum and excluded an atrial septal defect. Transoesophageal echocardiography showed anomalous attachment of a pulmonary vein into the region of a sinus venosus defect (n = 3) but did not show anomalous connexions to the superior caval vein (n = 3) or the inferior caval vein (n = 1). Transoesophageal echocardiography provides a reliable method of diagnosing or excluding an atrial septal defect in patients with inconclusive transthoracic findings and is of particular diagnostic value in sinus venosus defects.

Adolescent↗
PubMed1991

Transoesophageal echocardiographic assessment of fixed subaortic obstruction in children.

OBJECTIVE: To evaluate the clinical usefulness of transoesophageal echocardiography in the assessment of children with fixed left ventricular outflow tract stenosis. PATIENTS AND METHODS: Eight consecutive children, aged over 5 years, with fixed subaortic stenosis and one child with fixed subpulmonary left ventricular outflow tract stenosis were prospectively assessed by precordial and transoesophageal echocardiography. RESULTS: Transoesophageal images of the left ventricular outflow tract were much clearer than precordial images in all patients except one with a prosthetic mitral valve. Improved visualisation provided further information on the nature of the lesion (additional chordal attachment of the mitral valve in one, accessory atrioventricular valve tissue with aneurysm formation in one), on the extent of the lesion (circumferential in three), and on the very close relation of a ridge to the aortic valve leaflets in one. Transoesophageal Doppler did not provide any additional information on aortic regurgitation and was unreliable for gradient estimation across the left ventricular outflow tract. CONCLUSIONS: Transoesophageal imaging provides an excellent means of visualising lesions in the left ventricular outflow tract and can be useful in a few children and adolescents in whom precordial echocardiography does not provide adequate information. The technique can also be used intraoperatively to define the full extent of the obstructive lesion and to assess residual lesions after surgery.

Adolescent↗
PubMed1991

Venous bullet embolism: a complication of airgun pellet injuries.

Bullet emboli are an interesting but rare occurrence and their management when situated in the venous system remains controversial. Two cases of venous bullet embolism to the right heart are reported due to airgun pellet injuries. Both cases required bullet embolectomy using cardio-pulmonary bypass.

Child↗
PubMed1990

Anomalous origin of the left coronary artery from the pulmonary trunk: elucidation with colour Doppler flow mapping.

Four infants and children with anomalous connection of the left coronary artery to the pulmonary trunk were studied with colour Doppler flow mapping. In three the diagnosis was only suspected when the colour Doppler study showed dilated intraseptal and epicardial vessels and an abnormal flow signal into the pulmonary artery in diastole; this latter signal localised the exact site of communication, which was not apparent on angiocardiography. Two of these patients had previously had operations for severe mitral regurgitation, the diagnosis of anomalous left coronary artery having been previously considered in one but missed despite aortic root angiography. The colour study in the fourth was largely confirmatory, operation without catheterisation being undertaken on the basis of the echocardiographic images. By contrast in two infants subsequently seen with congestive cardiomyopathy the demonstration of flow direction in the left coronary artery confirmed that it was normally connected to the aorta. Colour Doppler flow mapping can show flow direction in the left coronary artery and from the mouth of an anomalous coronary artery into the pulmonary artery, thus simplifying the diagnosis and allowing the site of the connection of the left coronary artery to the pulmonary artery to be determined with precision.

Cardiomyopathy, Dilated↗
PubMed1990

Coarctation of the aorta and post-stenotic aneurysm formation.

Despite earlier angiography, post-stenotic aneurysm of the aorta was an unexpected finding at operation in two patients with coarctation. One aneurysm was found in an intercostal artery in a 19 year old man and the other was a false aneurysm just distal to the coarctation site in a 7 year old boy. These aneurysms are fragile, apt to rupture, and difficult to diagnose preoperatively. Though local factors such as jet streams and bacterial endocarditis may influence their formation there must be an underlying generalised weakness in the arterial wall. A coarctation should not be regarded as an isolated arterial abnormality because it may be a feature of a more generalised disease. Because of the risk of rupture, which may not be prevented by antihypertensive treatment, operation should not be delayed in any age group.

Adult↗
PubMed1989

Doppler flow characteristics in the assessment of pulmonary artery pressure in ductus arteriosus.

The Doppler spectral pattern of flow through the ductus arteriosus was studied in 117 patients. In 37 who underwent catheterisation, Doppler records and aortic and pulmonary artery pressure were available (21 simultaneously with two catheters) for review while the others had surgical ligation of the duct on the basis of the results of non-invasive tests. Four flow patterns were obtained: (a) continuous flow, maximum velocity in late systole with gradual fall throughout diastole; (b) continuous flow, high systolic flow with rapid fall to a very low early diastolic velocity maintained throughout diastole; (c) continuous low velocity, maximum in late diastole; and (d) bidirectional flow. Flow pattern (a) was associated with normal or slightly raised pulmonary artery pressure; (b) with raised pulmonary artery pressure; and (c) and (d) with pulmonary artery pressure at systemic values. Comparison of the Doppler and measured pressure differences between the great arteries was reasonably good for peak values but poor for the trough readings. Doppler ultrasound clearly showed ductal flow; the flow pattern gave an indication of the pulmonary artery pressure, but pressure measurement by application of the Bernoulli equation to the flow velocities cannot yet be regarded as reliable.

Adolescent↗
PubMed1989

Atrial myxoma as the cause of acute lower limb ischaemia in a teenager.

We report a case of a previously well teenager presenting with a sudden cardiovascular collapse due to a saddle embolus. This required immediate surgical intervention. Histology of the embolic material showed it was myxomatous. Echocardiography confirmed the diagnosis and the patient made an uneventful recovery following excision of the right arterial myxoma.

Adolescent↗
PubMed1988

Management of an infected pseudoaneurysm following an aortoventriculoplasty.

An 11-year-old child developed prosthetic valve endocarditis with associated infection of the prosthetic and pericardial patches 6 months following an aortoventriculoplasty. Angiography revealed an associated false aneurysm which communicated with both the ascending aorta and the right ventricular outflow tract. This report discusses the surgical management of this patient.

Aneurysm, Infected↗
PubMed1988

Adrenocortical hormone concentrations in children during cardiopulmonary bypass with and without pulsatile flow.

Plasma cortisol and ACTH concentrations were measured in two groups of children (aged 1-16 yr). Ten children underwent routine (non-pulsatile) cardiopulmonary bypass and 10 underwent pulsatile bypass under moderate hypothermia (28-32 degrees C). Comparable increases in cortisol and ACTH concentrations were demonstrated at the onset of bypass and the concentrations of both hormones increased during bypass. In the post-bypass period plasma cortisol concentration increased sharply; there was no further increase in the plasma ACTH concentration. By 24 h the concentrations of both hormones had declined towards baseline values. There were no significant differences between the groups.

Adolescent↗
PubMed1987

Concomitant cor triatriatum and coronary sinus total anomalous pulmonary venous connection.

Successful repair of the rare anomaly of concomitant cor triatriatum and coronary sinus total anomalous pulmonary venous connection in a neonate is described. The presence of pulmonary venous obstruction or cardiomegaly, or both, in a child with total anomalous pulmonary venous connection should alert to the possibility of a coexistent cor triatriatum.

Cor Triatriatum↗
PubMed1987

Aortic origin of right pulmonary artery: successful surgical correction in three consecutive patients.

Over a period of four years (1981 through 1984), 3 infants with aortic origin of the right pulmonary artery were seen in our surgical unit. Two infants had a persistent ductus arteriosus, which arose from the left subclavian artery in 1 of them who also had a right-sided aortic arch. There were no other associated abnormalities. Preoperative diagnosis was established by echocardiography in 2 infants. Anatomical surgical correction was undertaken in all 3 infants under cardiopulmonary bypass. There were no operative deaths. One child required reoperation at 15 months for anastomotic stenosis. All 3 children were well two to five years postoperatively with scintillographic evidence of normal ventilation and perfusion. Our experience indicates that this rare but severe congenital cardiac anomaly is easily diagnosed by echocardiography, and confirms that it is eminently amenable to surgical correction.

Cardiopulmonary Bypass↗
PubMed1987

Doppler ultrasound in the assessment of severity of coarctation of the aorta and interruption of the aortic arch.

Doppler ultrasound was used to investigate 48 infants and children (age 2 days-16 years, weight 1.0-58 kg) with aortic arch abnormalities. In only 38 of the 42 with an important coarctation was an increased blood flow velocity from the distal arch demonstrated. In three with interruption of the aortic arch an increased velocity recorded from the region of the distal arch was thought to represent ductal flow. There was little difference between the peak to peak and instantaneous maximum gradients in the 20 patients with important coarctation in whom direct pressure measurements both proximal and distal to the obstruction were made at catheterisation. There were poor agreements between Doppler and measured peak to peak and instantaneous gradients in the 17 patients found to have both an increased velocity and important coarctation. It is concluded that although an increased blood flow velocity in the distal arch is usually demonstrated in coarctation this may not occur with severe obstruction. Furthermore, the maximum velocity is not related to the anatomical severity of the obstruction and the Doppler estimate of pressure drop in coarctation may not even reliably predict that measured at catheterisation.

Adolescent↗
PubMed1986

Somatosensory evoked potentials in the detection of spinal cord ischemia in aortic coarctation repair.

Cortical somatosensory evoked potential (SEP) monitoring was used in 15 patients 2 to 50 years old undergoing repair of aortic coarctation to detect the onset of spinal cord ischemia during the cross-clamp period. Three different response patterns were observed. In 8 patients (53%), the SEP remained unchanged throughout the cross-clamping. This was designated a type 1 response. Six patients (40%) showed a gradual deterioration in the SEP after 15 minutes of cross-clamping (type 2 response). All SEPs returned to normal levels within 5 minutes of release of the clamp. One patient (7%) demonstrated a decline in SEP commencing prior to the application of the cross-clamp when an intercostal vessel was controlled with slings. The SEP completely disappeared within 5 minutes of cross-clamping, but after 19 minutes the repair was completed and the SEP returned within 3 minutes of reperfusion (type 3 response). No patient sustained neurological sequelae of repair. We believe that SEP monitoring offers the potential to identify the patient at risk of developing spinal cord ischemia intraoperatively before irreversible damage occurs. However, it is susceptible to deep halothane anesthesia, which abolishes all cortical responses and requires expert monitoring.

Adolescent↗