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Biomedical subjects

K C Pringle

Publications and source records attributed to K C Pringle.

At least 37 records · Page 2Linked to original sources

Fetal diagnosis and fetal surgery.

Accurate fetal diagnosis became possible by the steadily increasingly complex techniques of amniocentesis, ultrasound, and ultrasound-guided fetal blood sampling and chorion villous sampling. A high degree of diagnostic accuracy for a wide variety of structural and metabolic anomalies is required. The field of fetal diagnosis has been extended to the point that a journal dedicated to this subject alone is a viable proposition. It is becoming apparent, however, that lesions that were well known and well understood when recognized in neonatal life appear in general to have a worse prognosis if the lesion is diagnosed in utero. Fetal surgery began with attempts to perform in utero transfusions for babies with erythroblastosis fetalis. For a while, there was competition between open surgical procedures and the percutaneous placement of blood through catheters introduced into the fetal peritoneal cavity from outside the mother's abdomen. For fetal transfusion, closed techniques proved far safer and just as efficacious. There has been a worldwide interest in shunting of hydrocephalus and obstructive uropathy. The results of shunting hydrocephalus have been disappointing, with most of the patients surviving, but most of the survivors being severely handicapped. The results of shunting obstructive uropathy were that only about 50 per cent of the babies survived, but it appeared that those that did survive did well. Other lesions that have been shunted have been hydrothoraces or fetal ascites. A limited number of open procedures have been carried out in the last few years in San Francisco, and it may well be that diaphragmatic hernia (in appropriately selected patients) will be a lesion that can be corrected by in utero surgery. The future of this field is exciting, but before this form of treatment becomes routine, the ethical implications of the possibility of fetal surgery must be defined much more clearly than is currently the case.

Female↗

Sodium deficit causing decreased weight gain and metabolic acidosis in infants with ileostomy.

The records of 11 infants, 25 to 38 weeks' gestation, with metabolic abnormalities induced by ileostomy fluid losses were reviewed. At operation for necrotizing enterocolitis (NEC) (9) or meconium ileus (MI) (2), they weighed between 1,100 and 3,100 g and were from one to 41 days old. All developed total body sodium depletion and metabolic acidosis from ileostomy bicarbonate loss. In seven, sodium depletion was severe enough to require supplementation; six initially lost or failed to gain weight despite being fed adequate diet and calories. However, after receiving sodium supplementation (three with NaCl and three with NaHCO3), these six patients gained weight and improved their metabolic acidosis. The other five subjects did not initially receive sodium supplementation. Four gained weight; one of these later received supplemental NaHCO3 for a metabolic acidosis. The fifth patient failed to thrive until his ileostomy was closed. All infants initially had urine Na less than 10 mEq/L and normal serum Na. All infants whose urine Na rose above 10 mEq/L and had serum HCO3- greater than or equal to 20 mEq/L grew adequately. A direct relationship existed between ileostomy output and sodium intake required for growth. This expressed mathematically (Na intake = 1.2 + [0.13 x ileostomy output] shows a basal sodium need (with no ileostomy output) of 1.2 mEq/kg/d and an additional requirement of 0.13 mEq/kg/d of sodium for each mL/kg/d of ileostomy output. We conclude that infants with ileostomies are at extreme risk of total body sodium depletion with resultant metabolic acidosis and inadequate weight gain. These infants require sodium supplementation with a combination of NaCl and NaHCO3.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗

Congenital anorectal anomalies: MR imaging.

Twenty-one patients with anorectal anomalies were evaluated with magnetic resonance (MR) imaging. In seven preoperative patients, MR imaging demonstrated the level of atresia correctly by showing the rectal pouch and sphincter muscles. The exact location and development of the sphincter muscles were estimated and associated anomalies involving the kidneys and the spine and its contents were evaluated. In 14 postoperative patients, the location of the pulled-through intestine was examined in relation to the sphincter muscles. MR imaging demonstrated operative complications affecting rectal continence--such as a misplaced neorectum, inadvertently pulled-through mesenteric fat, and an implantation mucous retention cyst--and provided objective data for individuals with persistent incontinence after surgery who were under consideration for repeat surgery. The authors recommend MR imaging in all patients being considered for repeat procedures and in any patient without prior surgery who is suspected of having a high anomaly; any degree of sacral agenesis; or spinal, genito-urinary tract, or cloacal anomalies.

Adolescent↗

Abdominal wall defects and obstructive uropathies. Aetiology and management.

Gastroschisis and omphalocele (exomphalos) are embryologically distinct, and for this reason each has its own distinct constellation of associated anomalies. The perinatal management of both gastroschisis and omphalocele addresses the controversy as to the best mode of delivery that has been expressed in the literature with regard to gastroschisis and has exercised many of those involved in antenatal diagnosis in the case of omphalocele. The post-delivery management of both of these defects is briefly discussed. Controversies surrounding the aetiology of renal dysplasia and whether urinary tract obstruction is a cause of dysplasia or an anomaly associated with dysplasia are also discussed. The options for therapy and the indications for an in utero shunting procedure are outlined as well as the controversy centred around the utility of an in utero shunt. The need for a prospective randomised trial is emphasised, together with the difficulty that is raised by the need to choose a limited number of prospective indices on which treatment decisions in such a trial must be based. The need for a long-term follow-up of all patients entered in such a trial is emphasised.

Abdominal Muscles↗

Development of fetal lamb lung and kidney in obstructive uropathy: a preliminary report.

Oligohydramnios, whatever the cause, results in lungs that are 'hypoplastic' or at least smaller than normal. The fine structure in such lungs has not been reported previously. Three fetal lambs had both ureters ligated at 60, 72 and 58 days of gestation. They were sacrificed at 117, 143 and 142 days of gestation. The lungs were fixed by tracheal perfusion at 15 mm Hg. Individual lobar volumes were determined, and the lungs were sampled for electron microscopy. Total lung volumes for 2 of the lambs were very close to those previously reported for lungs of equivalent gestation with diaphragmatic hernia. The third lamb had a twin that had been unrecognised at the time of the original procedure. This lamb's lung volumes were normal. The morphological appearances of the lungs at the electron microscopy level are not normal but dramatically different from those previously reported in lambs with diaphragmatic hernia, phrenic nerve avulsion, and fetal tracheostomy. The lungs of the lamb with bilateral ureteric ligation and a normal twin were essentially normal. These preliminary findings point to the need for more studies of lung structure in oligohydramnios/obstructive uropathy models. However, the normal lungs in a lamb with grossly dysplastic kidneys and a normal twin argue against any important renal trophic factor in lung development in the fetal lamb. An interesting sidelight to this investigation was the unequivocal demonstration that early ureteric ligation results in true renal dysplasia in the fetal lamb. The kidneys of the lamb sacrificed at 117 days were smaller than normal and grossly dysplastic. The kidneys of the lambs that underwent ureteric ligation at 60 and 72 days were structurally different, with the ureters ligated at 60 days being small and dysplastic, while those with the ureters ligated at 72 days were larger and appeared almost polycystic.

Animals↗

A reassessment of pregnancy staging.

A system of staging pregnancy that is directly related to normal development is proposed to replace the currently used 'trimester' system. If accepted, this concept of staging could be applied across species without the likelihood of a grossly incorrect assessment of the stage of development. In contrast to this, the division of a pregnancy into trimesters is based upon an accident of mathematics and bears no relationship to human development. The proposal is to divide pregnancy into three stages, termed 'horizons'. First is the 'embryonic horizon' from fertilisation until the end of the 8th week from fertilisation, i.e., 10 weeks from the first day of the last menstrual period (LMP). The 'early fetal horizon' extends from the end of the embryonic phase to the 25th week of gestation (i.e., 25 weeks from the first day of the LMP). This horizon is divided into the 'primitive phase' (up to the 15th week of gestation) and the 'transitional phase' (from the 15th to the 25th week of gestation). The 'late fetal horizon' extends from 25 weeks to beyond term and is divided into the 'premature phase' (from 25 weeks to 36 weeks of gestation), the 'mature phase' (36 weeks to term) and the 'post-mature phase' which extends from term to about 45 weeks of gestation. The importance of this phase is the fact that perinatal morbidity and mortality is proportional to the length of time the gestation continues beyond maturity. It must be stressed that the terms 'horizon' and 'phase' are intentionally imprecise. This is to emphasise that human development is a continuum and not a series of steps.

Embryonic and Fetal Development↗

Balloon dilatation of esophageal stenosis in children.

Balloon dilatation of benign esophageal strictures is an accepted mode of therapy in adults. This report describes balloon dilatation in 20 consecutive infants and children. The lesions treated include 11 strictures at surgical anastomotic sites, seven restrictive Nissen fundoplications, and three nonanastomotic esophageal strictures. One patient had two lesions. Most dilatations were performed on an outpatient basis without anesthesia. All strictures responded immediately to dilatation. In most cases, long-term resolution occurred after three or fewer procedures. A subgroup of patients was identified in which a prolonged course of treatment was needed. These included patients with long strictures due to esophageal atresia, patients with chronic severe esophagitis, and patients with strictures at the site of esophageal perforation. No significant complications were encountered. Balloon dilatation of esophageal stenosis in children is effective and safe and should be considered before other methods of treatment are used.

Catheterization↗

Successful treatment of hepatic venocclusive disease in a bone marrow transplant patient with side-to-side portacaval shunt.

Hepatic venocclusive disease developed in a 14-yr-old white girl after allogenic bone marrow transplantation from an HLA-identical sibling donor. Clinical diagnosis of venocclusive disease was based on the development of ascites, hepatomegaly, and jaundice 3 wk after transplantation. Current treatment of hepatic venocclusive disease is ineffective. The pathophysiology of the hepatic lesion suggests that construction of a side-to-side portacaval shunt should be beneficial in relieving the ascites and preventing further hepatic damage. Because the ascites was refractory to medical therapy and she was clinically deteriorating, a side-to-side portacaval shunt was performed. Histologic examination of a liver biopsy specimen obtained at surgery documented the presence of venocclusive disease. Postoperatively, the patient diuresed and returned to her baseline weight. One year after surgery the patient was doing well, her weight was stable, and she was being maintained on salt restriction alone. While the resolution of ascites and improvement of hepatic function in our patient after side-to-side portacaval shunt does not guarantee that such an approach will be uniformly successful, it should serve to encourage others to consider such therapy for this frequently devastating complication of chemoradiation therapy.

Adolescent↗

Magnetic resonance imaging as an adjunct to planning an anorectal pull-through.

Magnetic resonance imaging (MRI) is a relatively new diagnostic tool that generates images of sections of the body taken in any plane. We report the use of MRI as a tool to plan surgical procedures in patients with imperforate anus, imaging the pelvis and lumbosacral spine in the sagittal, transverse, and coronal planes. MRI clearly reveals the extent of the pelvic musculature even in patients with severe sacral agenesis. MRI is extremely useful in assessing patients under consideration for reoperation, clearly demonstrating the relationship between the pulled through colon and the "striated muscle complex." A very useful addition is the ability, on the same study, to detect previously unsuspected anomalies such as tethered cord, lipoma of the filum terminale, and renal dysplasia. We conclude that MRI is a very useful examination in selected patients with imperforate anus.

Adolescent↗

Permanent cardiac pacemaker implant in the fetal lamb.

To investigate the feasibility of permanent cardiac pacing in the fetal lamb, we attempted five implants in lambs between 100 and 115 days of gestation. The lambs were approached by a left thoracotomy done through a transverse hysterotomy in the ewe. An epicardial lead was fixed to the left ventricle. Pacing parameters were measured and the lead was connected to an Enertrax implantable pulse generator. A pouch was created for the generator deep to the latissimus dorsi. Documentation of pacing was obtained electrocardiographically; pacing faster than the fetal intrinsic rate. The muscle and the fetal skin were closed. The pacemaker was programmed to a rate of 70 in the ventricular inhibited (VVI) mode and the uterine and abdominal wall incisions were then closed. One lamb was successfully delivered by Cesarean section at term. Pacing parameters were measured at birth and one month later. There were small changes in the pacing lead function parameters as the implant progressed into the chronic phase. They were within the capacity of the generator to pace with a margin of safety. Four lambs died in utero and were delivered 5 to 26 days post-implant. We conclude that permanent cardiac pacemaker implantation is feasible in the fetal lamb and with further development, it may eventually be used in humans in the treatment of fetal congestive heart failure due to bradyarrhythmias.

Animals↗

Sacrococcygeal teratoma.

The definition, natural history and prognosis of sacrococcygeal teratoma (SCT) are reviewed. Two cases of SCT are presented in detail. Both were diagnosed well before delivery and required intensive perinatal management. Both babies survived intact after removal of 30-50% of total body mass. Case selection for antenatal therapy remains a problem. Prospects for antenatal therapy are reviewed.

Adult↗

Per anal balloon dilatation of a post-necrotizing enterocolitis stricture of the sigmoid colon.

Per anal balloon dilatation of a sigmoid colon stricture caused by necrotizing enterocolitis allowed identification of a more proximal lesion which would otherwise have gone radiographically undetected. Repeated dilatations at two weeks and four weeks following the initial dilatation of the stricture resulted in relief of the stricture and obviated the need for surgical treatment of this lesion.

Angioplasty, Balloon↗

Chronic intestinal pseudoobstruction in young children.

We studied 8 young children (4 boys and 4 girls) with chronic intestinal pseudoobstruction. Intestinal pseudoobstruction, recurrent urinary tract infections, and dysuria occurred between the ages of a few weeks to 5 yr old. All had marked dilatation of the entire gastrointestinal tract distal to the esophagus, and megacystis. Conventional pathologic examinations of the full-thickness specimens of the gastrointestinal tract were normal in 5 and abnormal in 2 patients. The abnormalities included increased fibrosis and lipofuscin pigment in the smooth muscle cells. Myenteric plexus examination, using the Smith's method in 2 patients, was normal. Biopsy specimens from urinary bladders examined in 3 patients revealed separation of individual smooth muscle cells by collagen fibers. Intestinal manometric studies performed in 3 patients showed only weak and infrequent contractions during fasting and after feeding. Severe and extensive dysfunction of the gastrointestinal and urinary tracts with relatively normal histologic appearance are typical for these children.

Abdomen↗

Fetal surgery: it has a past, has it a future?

The past history of fetal surgery is briefly reviewed. The current controversies revolving around the fetal treatment of hydrocephalus and obstructive uropathies (posterior urethral valves, prune belly syndrome, hydronephrosis) are compared and contrasted with the remarkably similar controversies that raged when fetal transfusions were first introduced. The future of fetal surgery is discussed in the light of the ethical issues raised by the prospect of fetal surgery and the rather disturbing medicolegal climate. There are already important legal precedents which will affect the field of fetal surgery. The strong opinion is expressed that fetal surgery must only remain an option offered to the mother and never forced upon her.

Congenital Abnormalities↗