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F C Ryckman

Publications and source records attributed to F C Ryckman.

At least 19 recordsLinked to original sources
PubMed1992

The predictive value of head ultrasound in the ECMO candidate.

Cranial ultrasound (US) examination is the screening technique of choice for assessing preexisting neurological damage in potential neonatal extracorporeal membrane oxygenation (ECMO) candidates. Currently, US evidence of intracranial hemorrhage greater than grade I in severity is a contraindication to ECMO at this ECMO center. In the current study, radiological findings were reviewed in 129 consecutive neonatal ECMO cases in an attempt to identify which pre-ECMO US findings were associated with the development of subsequent intracranial complications while on ECMO. Pre-ECMO head US, post-ECMO head US, and head computed tomography (CT) scans were reviewed retrospectively by one radiology team. Ventricular, parenchymal, and extraaxial fluid abnormalities were recorded for each case. Pre-ECMO US findings were then correlated with the subsequent development of significant intracranial radiological abnormalities noted on post-ECMO studies as well as with clinical data regarding ECMO course and outcome. Results showed that infants with evidence of severe edema or periventricular leukomalacia on pre-ECMO imaging had a 63% incidence of subsequent major intracranial complications. This represents a significantly higher risk than in candidates with a normal examination or evidence of grade I intracranial hemorrhage, subependymal cysts, or mild edema. These results suggest that infants with sonographic evidence of ischemic or anoxic damage on pre-ECMO US are at high risk for the development of significant intracranial complications if ECMO therapy is instituted.

Brain↗
PubMed1992

A prospective, multicenter, randomized study of high versus low positive end-expiratory pressure during extracorporeal membrane oxygenation.

To test the hypothesis that increased positive end-expiratory pressure (PEEP) could prevent deterioration of pulmonary function and lead to more rapid recovery of lung function, we randomly assigned 74 patients undergoing extracorporeal membrane oxygenation (ECMO) at four centers to receive either high (12 to 14 cm H2O) or low (3 to 5 cm H2O) PEEP. The two groups were similar in terms of weight, gestational age, diagnosis, and pre-ECMO course. All other aspects of care were identical. Dynamic lung compliance was measured at baseline and every 12 hours. Radiographs of the chest were obtained daily. Survival rates were similar in the two groups: 36 of 40 for low PEEP and 34 of 34 for high PEEP. The duration of ECMO therapy was 97.4 +/- 36.3 hours in the high-PEEP group and 131.8 +/- 54.5 hours in the low-PEEP group (p less than 0.01). Dynamic lung compliance throughout the first 72 hours of ECMO was significantly higher in patients receiving high PEEP. Radiographic appearance of the lungs correlated well with lung compliance: patients receiving high PEEP had significant deterioration of the radiographic score less frequently than those receiving low PEEP. High PEEP also was associated with significantly fewer complications. We conclude that PEEP of 12 to 14 cm H2O safely prevents deterioration of pulmonary function during ECMO and results in more rapid lung recovery than traditional lung management with low PEEP.

Extracorporeal Membrane Oxygenation↗
PubMed1992

Hepatobiliary scintigraphy in pediatric liver transplant recipients.

The clinical usefulness of hepatobiliary scintigraphy was evaluated in pediatric liver transplant recipients. One hundred fifteen hepatobiliary scintigraphic studies were performed in 30 patients who received 22 whole liver and 16 segmental grafts. Parameters that were useful in predicting an adverse outcome were failure to visualize excreted radiopharmaceutical at or beyond the biliary anastomosis on a study performed within 24 hours after transplant, and persistent or increasing delay in the time of visualization of excreted radiopharmaceutical. Abnormalities of liver uptake and excretion were seen in rejection, but they were also seen in patients who remained well without rejection or parenchymal disease. Significant biliary leaks were identified in the three cases in which they were known to be present. In liver transplant recipients, hepatobiliary imaging is useful in predicting graft survival and identifying biliary leaks.

Adolescent↗
PubMed1992

Monoethylglycinexylide formation in assessing pediatric donor liver function.

Lidocaine metabolism to monoethylglycinexylide (MEGX) has been described as a novel method to assess liver function in adult transplant donors and recipients. While this assay appears to offer a number of advantages over existing liver function tests, limited work has been done to evaluate its potential in the pediatric population. This study evaluated MEGX formation in potential pediatric liver donors (n = 35) and a control group of children (n = 16). The mean MEGX formation was significantly higher in pediatric donors than in the control group (156 +/- 62 vs 106 +/- 33 ng/ml, p < 0.05). No correlation with age, total bilirubin, liver transaminases, or alkaline phosphatase could be made within each group. Significant differences in MEGX levels were noted when each group was compared to its adult counterpart. Both pediatric donors and controls had greater mean MEGX formation than has been reported for adult donors and controls (156 +/- 62 vs 127 +/- 61 ng/ml, p < 0.05 and 106 +/- 33 vs 72 +/- 36 ng/ml, p < 0.05, respectively). Drugs that alter lidocaine pharmacokinetics and their potential influence on MEGX formation were evaluated in the pediatric donor group. Donors exposed to hepatic enzyme-inducing drugs had a higher mean MEGX formation (187 +/- 60 vs 146 +/- 63 ng/ml). No significant differences were noted between donors receiving and not receiving vasopressors. In conclusion, the significant differences between pediatric and adult MEGX formation should be noted when establishing reference or normal ranges for this diagnostic test. Furthermore, concomitant drug therapy may significantly alter MEGX formation.

Adult↗
PubMed1992

Left-lobe hepatic transplants: spectrum of normal imaging findings.

The limited availability of suitable size-matched donor whole organs has been a major cause of morbidity and mortality in infants and children requiring liver transplantation. Techniques for transplanting segments of the liver have successfully addressed this problem. The surgical anatomy of the left hepatic lobe transplant is unique in three primary respects: the cut edge, the presence of an enteric Roux loop for biliary drainage, and the alteration in the position and number of hepatic vessels. The spectrum of normal imaging findings in 17 left-lobe allografts is illustrated.

Anastomosis, Surgical↗
PubMed1992

Liver transplantation in children.

Children with end-stage liver disease now have a greater chance of survival through treatment with hepatic transplantation. This article reviews the pediatric liver transplantation process, including selection and evaluation of candidates, operative procedures, postoperative complications, and long-term survival.

Biliary Atresia↗
PubMed1992

Rapid improvement in the renal tubular dysfunction associated with tyrosinemia following hepatic replacement.

The postoperative management of patients with hereditary tyrosinemia type I (McKusick 27670) following liver transplantation is often complicated by the renal tubular dysfunction associated with this disease. To characterize better the temporal course of the improvement in renal excretory activity following hepatic replacement, renal tubular function and metabolite excretion were studied in a 4-year-old girl with hereditary tyrosinemia during the immediate post-transplantation course. Tubular reabsorption of bicarbonate and phosphate were normal 5 days following transplantation, in contrast to glucosuria, hyperaminoaciduria, and tyrosyluria, which persisted for approximately 3 weeks. After hepatic replacement, serum amino acid concentrations returned to normal and succinylacetone was no longer detected in the urine. This is the third tyrosinemia patient reported to achieve complete resolution of urinary abnormalities following transplantation, and the only patient in whom renal tubular function was formally assessed within the first postoperative week.

Amino Acid Metabolism, Inborn Errors↗
PubMed1991

Selection criteria for liver transplant donors.

As the number of successful liver transplants has increased, the demand for donors has outpaced the supply. Approximately 25% of patients die awaiting an appropriate donor. Current criteria for assessing potential donors need to be closely examined. Fifty-six potential donors were evaluated by our transplant team by utilizing standard liver function tests (LFT's)-SGOT, SGPT, bilirubin. Additionally, a lidocaine metabolism test was performed by giving a 1 mg/kg IV dose of lidocaine over 1 minute and measuring the accumulation of the major metabolite monoethylglycinxylidide (MEGX) at 15 minutes by fluorescent polarization immunoassay (Abbott Diagnostics, Abbott Park, IL). Previous work has suggested that a MEGX less than 50 ng/mL is associated with initial non-function. Thirty-four donors were transplanted (group I) and all had initial function (all MEGX values were greater than 50). Twenty-two donors (39%) were judged unacceptable (group II) by our transplant team and by outside centers based upon one of the following criteria: II A) elevated LFT's--8, 11 B) donor age--5, II C) donor instability--4, II D) no available recipient--3, II E) miscellaneous--2. Standard LFT's were not statistically different in the donors used and in those not used when excluding category II A. Six of seven donors excluded in group I had acceptable MEGX values indicating they may have been transplantable. Ten of 12 patients excluded in groups II B-D had normal LFT's and nine of 12 had acceptable MEGX values indicating they may have been transplantable also. In this era of organ shortage, a reevaluation of donor selection criteria utilizing new tests like MEGX may be necessary to meet the increased need.

Adolescent↗
PubMed1991

Cardiac arrest in the ECMO candidate.

Extracorporeal membrane oxygenation (ECMO) improves survival in appropriately selected full-term neonates with severe respiratory failure. The clinical course and outcome of infants placed on ECMO after sustaining a cardiac arrest is not known. This study reviews the characteristics and outcome of 10 neonates, identified by retrospective review, placed on ECMO at Children's Hospital Medical Center (CHMC), Cincinnati, OH, after sustaining a cardiac arrest. Long-term survival in this group was 60%, significantly less than the 87% overall ECMO survival in infants at CHMC (P less than .01). Survivors and nonsurvivors in the cardiac arrest group were similar with regard to gestational age, birth weight, Apgar scores, and arterial PO2 prior to cannulation. Nonsurvivors had an ECMO course complicated by progressive multisystem organ failure. Head computed tomography obtained at the time of discharge demonstrated right-sided brain lesions in three of six survivors. Despite these radiographic findings, early clinical follow-up suggests adequate growth and development with no individuals demonstrating a severe neurological deficit. Thus, ECMO can play a role in the resuscitation of neonatal ECMO candidates sustaining cardiac arrest prior to or at the time of cannulation. Early clinical follow-up suggests adequate preservation of neurological function in this extremely high-risk group.

Brain Diseases↗
PubMed1991

Segmental orthotopic hepatic transplantation as a means to improve patient survival and diminish waiting-list mortality.

Pediatric liver transplantation continues to be limited by the availability of suitable liver donors, a factor that restricts programmatic development and ultimately contributes to death on the recipient waiting list. We report the application of segmental liver transplantation as a technique to address both these problems as well as improving the outcome of the child undergoing the transplant procedure. Since 1986, 37 children have undergone orthotopic liver transplantation. Twenty-three children have received whole-organ grafts; 81% survived. Of those receiving whole-organ grafts, 15% had arterial thrombotic complications and 23% required retransplantation. More importantly, 29% of those children listed for transplantation died while waiting for a donor organ to become available, with a mean interval of 1.7 months (range, 2 days to 4.5 months). Since July 1988, segmental liver transplantation has been a component of our therapeutic armamentarium, and of the past 20 liver recipients, 16 have received a left lobe segmental graft. The results of the segmental transplant series have shown striking improvements. First, no child has died while awaiting donor organ availability. Second, segmental liver recipient survival is equivalent to that of whole-organ graft recipients (81%). Third, hepatic arterial thrombosis, especially a problem in high-risk infant transplants, was reduced by this technique (5%). Retransplantation due to graft complications has not increased (21%). These data suggest a vital role for segmental liver transplantation not only as a remedial salvage procedure for the critically ill child, but also as a primary transplant option.

Adolescent↗
PubMed1991

Changes in cardiac function during extracorporeal membrane oxygenation for persistent pulmonary hypertension in the newborn infant.

The effects of extracorporeal membrane oxygenation (ECMO) on cardiac function and its determinants (preload, afterload, contractility, and heart rate) are largely unknown, although some evidence exists that function may decrease. To determine whether cardiac function decreases and what changes in the determinants take place during and after ECMO, we observed 26 newborn infants with persistent pulmonary hypertension. Serial echocardiograms were performed before ECMO, during maximum cardiopulmonary bypass, and after ECMO. Cardiac function was assessed by using standard echographic ejection phase indices (shortening fraction and cardiac output). Heart rate, preload (left ventricular end-diastolic dimension and area), afterload (left ventricular end-systolic wall stress), and contractility (relationship between velocity of circumferential fiber shortening and wall stress) were also measured. Ejection phase indices significantly decreased during ECMO (shortening fraction 33% to 25%, cardiac output 205 to 113 ml/kg/min; p less than 0.05) and returned to normal after ECMO (shortening fraction 26% to 34%, cardiac output 107 to 240 ml/kg/per minute; p less than 0.05). Heart rate also significantly decreased during ECMO (158 to 118 beats/min; p less than 0.05). Preload significantly increased after ECMO (left ventricular end-diastolic dimension 1.4 to 1.6 cm, left ventricular end-diastolic area 1.9 to 2.2 cm2; p less than 0.05). There were no significant changes in contractility and afterload during any study period. We conclude that, although left ventricular ejection phase indices and heart rate decreased during ECMO, these changes were transient and resolved when bypass was terminated. Contractility and afterload did not appear affected by bypass.

Bacterial Infections↗
PubMed1990

Multiple endocrine neoplasia type II B with symptoms suggesting Hirschsprung's disease: a case report.

A 3-year-old child was referred with a tentative diagnosis of Hirschsprung's disease because of life-long constipation and "megacolon" demonstrated radiographically. Our rectal biopsy revealed hyperganglionosis suggestive of multiple endocrine neoplasia (MEN) type II B. This, in addition to an elevated serum calcitonin level, prompted surgical removal of her thyroid, which appeared grossly normal but on sectioning, contained a medullary carcinoma in each lobe. She remains disease-free 5 years later. Gastrointestinal symptoms are a significant component of the MEN type II B syndrome, and often antedate the full phenotypic expression of the syndrome and the development of potentially lethal endocrine neoplasms. On the basis of this experience, it is recommended that MEN II B be included in the differential diagnosis of chronic constipation.

Child, Preschool↗
PubMed1990

Antimurine antibody formation following OKT3 therapy.

OKT3 is an IgG2a murine monoclonal antibody directed against the CD3 antigen receptor of human T lymphocytes. A major concern with OKT3 treatment in solid organ transplant recipients is the development of antimouse antibody, which may preclude retreatment with this agent. We have administered OKT3 on 215 occasions (150 renal, 34 hepatic, 26 cardiac, 5 pancreatic) in 179 patients between April 1982 and December 1988. The mean duration of treatment was 10.5 days (range, 2-22 days). Antimouse antibody data were analyzed on the most recent 133 treatment courses where the antibody status was available pretreatment. Determination of antimouse antibody production was elicited by ELISA technology at days 0, 7, 14, and 28 of OKT3 treatment. Patients were categorized according to the antibody response as follows: (a) absence of antibody; (b) low titer (1:100); or (c) high titer (greater than or equal to 1:1000). Our earlier experience has demonstrated that retreatment with OKT3 is successful in groups a and b. The development of antimurine antibodies was analyzed with regard to the following parameters: (1) The duration of OKT3 treatment; (2) treatment type (prophylactic, primary, or secondary); (3) primary treatment or retreatment; (4) concomitant immunosuppressive regimen (double or triple therapy); (5) dosage of concomitant immunosuppressive drugs; and (6) transplant organ type. The following results were obtained. (1) Duration of treatment had no effect on antibody production (11.0 days in antibody negative and 10.0 days in antibody positive). (2) There was no difference in antibody formation rates for the first treatment of OKT3 when it was used as prophylaxis (26%), primary (19%), or secondary (27%) therapy. (3) Antibody formation rate with first treatment was 29%; with retreatment, patients who were antibody negative following first treatment became positive in 28% of cases, and retreated patients who were low titer positive following first treatment converted to high titer in 57% of cases. (4) Antibody formation was higher in patients receiving double immunosuppressive therapy (36%) than in those receiving triple immunosuppressive therapy (21%) during OKT3 treatment. (5) Concomitant immunosuppression was lower in the antibody-positive group during OKT3 therapy: steroids, 61 mg/day vs. 52 mg/day; azathioprine, 89 mg/day vs. 66 mg/day; CsA, 317 mg/day vs. 186 mg/day. (6) Antibody formation rates were lower in non-renal transplants following first treatment with OKT3 (liver 17%, heart 17%, kidney 28%); this reflects the higher doses of concomitant immunosuppressive therapy used in nonrenal transplants.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Continuous hemodiafiltration in children.

Continuous arteriovenous hemofiltration is a form of renal replacement therapy whereby small molecular weight solutes and water are removed from the blood via convection, alleviating fluid overload and, to a degree, azotemia. It has been used in many adults and several children. However, in patients with multisystem organ dysfunction and acute renal failure, continuous arteriovenous hemofiltration alone may not be sufficient for control of azotemia; intermittent hemodialysis or peritoneal dialysis may be undesirable in such unstable patients. Recently, the technique of continuous arteriovenous hemodiafiltration has been used in many severely ill adults. We have used continuous arteriovenous hemodiafiltration in four patients at Children's Hospital Medical Center. Patient 1 suffered perinatal asphyxia and oliguria while on extracorporeal membrane oxygenation. Patients 2 and 4 both had Burkitt lymphoma and tumor lysis syndrome. Patient 3 had septic shock several months after a bone marrow transplant. All had acute renal failure and contraindications to hemodialysis or peritoneal dialysis. A blood pump was used in three of the four patients, while spontaneous arterial flow was adequate in one. Continuous arteriovenous hemodiafiltration was performed for varying lengths of time, from 11 hours to 7 days. No patient had worsening of cardiovascular status or required increased pressor support during continuous arteriovenous hemodiafiltration. The two survivors (patients 2 and 4) eventually recovered normal renal function. Continuous arteriovenous hemodiafiltration is a safe and effective means of renal replacement therapy in the critically ill child. It may be ideal for control of the metabolic and electrolyte abnormalities of the tumor lysis syndrome.

Acute Kidney Injury↗
PubMed1989

Taurocholate transport by basolateral plasma membrane vesicles isolated from human liver.

Transport of taurocholate into the hepatocyte against unfavorable chemical and electrical gradients occurs via a sodium-dependent, carrier-mediated transport system. Although this cotransporter has been characterized in the rodent, it has not been demonstrated in man. Therefore, we utilized human liver, obtained via multiorgan donation but not used for transplantation, to prepare basolateral (sinusoidal) liver plasma membrane vesicles by a Percoll gradient method. Na+,K+-ATPase, a marker enzyme for the basolateral domain, was enriched 28.9-fold in the final membrane fraction compared with homogenate, whereas the bile canalicular membrane enzymes Mg++-ATPase and alkaline phosphatase were enriched only 3.4- and 6.4-fold, respectively. Marker enzyme activities for endoplasmic reticulum, lysosomes and mitochondria were not enriched compared with homogenate. Integrity of the membrane vesicles was confirmed by the demonstration of Na+-dependent concentrative uptake of the amino acid L-alanine (estimated intravesicular volume of 0.59 microliter per mg protein). An inwardly directed 100 mM Na+ gradient stimulated the initial rate of 2.5 microM taurocholate uptake and energized a transient 2-fold accumulation of the bile acid above equilibrium ("overshoot"). In contrast, uptake was slower and no overshoot occurred with a K+ gradient. A negative intravesicular potential, created by altering accompanying anions or by valinomycin-induced K+ diffusion potentials, did not enhance taurocholate uptake, suggesting an electroneutral cotransport mechanism. Chloride as the accompanying anion stimulated the initial rate of uptake compared with anions of lesser or greater lipid permeability. Na+-dependent taurocholate (4 microM) uptake was significantly inhibited by 250 microM cholate, taurocholate, glycocholate, taurochenodeoxycholate and bromsulfophthalein.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Mediastinal hemorrhage during extracorporeal membrane oxygenation.

A case of mediastinal hemorrhage along with hemorrhage into a pneumatocele while on extracorporeal membrane oxygenation (ECMO) is presented. Computerized tomography of the chest was utilized to support the diagnosis. Barotrauma to the lungs best explains the inciting event that allowed the hemorrhage to occur once the patient was heparinized for ECMO. This complication serves to point out the importance of commencing early ECMO support before widespread pulmonary and mediastinal barotrauma develops.

Barotrauma↗
PubMed1989

Factors affecting urea clearance during continuous hemodiafiltration in the canine model.

Continuous hemofiltration (CH) for the treatment of hypervolemia and electrolyte abnormalities in critically ill patients with acute renal failure has been shown to be an effective mode of therapy. This technique offers several advantages over peritoneal dialysis or hemodialysis: it is technically less complex, provides efficient ultrafiltration, and produces fewer hemodynamic disturbances. Recently, continuous hemodiafiltration (CHD) using a flow of dialysate fluid into the ultrafiltration chamber has been reported to augment urea clearance. The purpose of this study was to determine the blood flow and dialysate flow characteristics for optimal clearance of urea and creatinine using this technique. Six mongrel dogs (mean weight, 8.0 +/- 1.1 kg) underwent bilateral nephrectomy to induce anuric renal failure. Postoperatively, the animals were fluid resuscitated and fed ad libitum. Twenty-four hours following nephrectomy, venovenous hemofiltration was instituted. Blood flow was regulated via a roller pump, while dialysate flow was regulated using an infusion controller. An Amicon-30S hemofilter was used in the circuit. Blood flow rates of 5, 10, 15, 20, 25, and 30 mL/kg/min were used. Hemodiafiltration using Dianeal 1.5% solution was used in each animal. Net fluid losses via ultrafiltration were replaced using lactated Ringer's solution. Three of six animals survived for the complete five-hour hemofiltration period. No marked disturbances in electrolyte serum concentrations, including hyperkalemia, were observed. BUN concentrations were reduced by 35% and creatinine by 26%. Variation of the dialysate flow rate did not influence clearance of either urea or creatinine. Instead, clearance appeared to be flow dependent, and it was markedly increased at flow rates greater than 15 mL/kg/min.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗