Acute hemodynamic effects of adjustable atrial septal defect closure in the lateral tunnel Fontan procedure

OBJECTIVES

This study evaluated the acute hemodynamic changes with atrial septal defect closure in the postoperative period in patients undergoing the Fontan procedure.

BACKGROUND

The adjustable atrial septal defect is a modification of the Fontan procedure designed to improve cardiac output and reduce systemic venous hypertension during the postoperative period. Limited information is available on the effects of inter-atrial shunting on the physiology of direct cavopulmonary connection.

METHODS

In 11 patients (aged 9 months to 14.5 years), the atrial septal defect was closed 8 h to 4.6 days (mean 1.7 days) postoperatively. Indications for closure included mean right atrial pressure < 15 mm Hg or arterial oxygen saturation < 80%, or both.

RESULTS

Data presented are mean values +/- 1 SD. Mean right atrial pressure was 13.4 +/- 3.0 mm Hg on admission to the intensive care unit, 10.0 +/- 2.0 mm Hg (p = 0.02) immediately before closure and 11.4 +/- 2.8 mm Hg (p = 0.02) after closure. There was a significant decrease in cardiac output, as calculated from arteriovenous oxygen saturation difference (26 +/- 9%, p = 0.003), Doppler aortic flow (19 +/- 9%, p = 0.0002) and ventricular volumes by two-dimensional echocardiography (20 +/- 8%, p = 0.0001). Arterial oxygen saturation increased from 82 +/- 5% to 94 +/- 4% (p = 0.0001), and arteriovenous oxygen saturation difference increased from 25 +/- 8% to 33 +/- 9% (p = 0.0001). Systemic oxygen delivery decreased from 727 +/- 354 to 655 +/- 325 ml/min per m2 (p = 0.02). One patient required reopening of the atrial septal defect.

CONCLUSIONS

These data demonstrate that a controlled right to left atrial shunt improves cardiac output and systemic oxygen delivery and facilitates the postoperative management of patients after the Fontan procedure. Atrial septal defect closure increases systemic saturation to normal values and prevents potential systemic embolization but significantly decreases oxygen delivery and might limit exercise tolerance.

Voice changes in acromegaly

The fundamental frequency of 14 patients undergoing hypophysectomy was studied. Eight patients had acromegaly, 3 had a prolactinoma, and 3 had nonfunctioning adenomas. The fundamental frequency of 22 normal, healthy volunteers was measured for comparison. In addition, the external size of the larynx of all patients and volunteers was measured and a relationship between external laryngeal size and the mean fundamental frequency was identified in the volunteers. The mean fundamental frequency in patients with acromegaly was significantly lower than the other 6 patients undergoing hypophysectomy and, in addition, was also lower than the 22 normal volunteers. Postoperatively the fundamental frequency of the acromegalic patients increased rapidly to within the expected normal range. Patients with acromegaly have a lowered fundamental frequency which is most likely due to altered vocal cord mass and elasticity, which is a reversible change. Patients with acromegaly can expect a rapid and complete return of normal fundamental frequency within 2 weeks of surgery to remove the pituitary adenoma.

Pediatric cardiology in the 1990s

OBJECTIVES

In 1991, all active board-certified pediatric cardiologists were polled by questionnaire to examine the relation of subspecialty training and motivational and satisfaction issues to practice characteristics.

BACKGROUND

Previous questionnaires with regard to manpower status and practice characteristics were published in 1967 and 1980. These indicated a field predominantly centered in academic medicine with growth in manpower close to predicted need.

METHODS

The questionnaire was mailed to 844 of 884 active board-certified pediatric cardiologists and was returned anonymously by 570, a 68% response rate.

RESULTS

Among respondents, the mean year in which fellowship training was completed was 1974. The average length of subspecialty training was 31 months for all respondents and 34 months among those completing training since 1981. Seventy-seven percent of subspecialty training centered on clinical training. Although there has been a slight increase in research training in recent years, only 18 respondents completed > or = 22 months of research training. Respondents devote a mean of 89% of professional hours to subspecialty activities and spend 63% of total hours in clinical care. Total hours, income and procedures were related to site of professional activity. Professional satisfaction was high in the factors considered more important: professional challenge and interaction, clinical resources, career security and clinical autonomy.

CONCLUSIONS

The field of pediatric cardiology is a subspecialty centered on patient care and performance of diagnostic and interventional techniques. Professional activities varied according to practice site. Pediatric cardiologists with basic research training and professional activity remain a minority. Satisfaction is high, with greatest satisfaction in professional interactions and least satisfaction with income and free time.

A nematode FMRFamide-like peptide, SDPNFLRFamide (PF1), relaxes the dorsal muscle strip preparation of Ascaris suum

PF1 (SDPNFLRFamide) is a FMRFamide-like peptide extracted from the free-living nematode Panagrellus redivivus. Here we show that this peptide causes a hyperpolarization of somatic muscle cells of the parasitic nematode Ascaris suum and a relaxation of the somatic muscle strip preparation. We have assessed whether or not the relaxation of Ascaris dorsal muscle strip by PF1 is due to (i) inhibition of the release of the excitatory neuromuscular junction transmitter acetylcholine (ACh), (ii) potentiation of the release of the inhibitory neuromuscular junction transmitter gamma-aminobutyric acid (GABA) or (iii) a direct inhibitory action of the peptide on the muscle cells. Under the experimental conditions described here, tonic ACh release does not seem to be involved in determining the resting membrane potential or resting tone of the Ascaris dorsal muscle strip and thus inhibition of tonic ACh release is unlikely to explain the relaxation elicited by the peptide. Furthermore, PF1 (100 nM-1 microM) inhibited the contraction of the muscle strip elicited by bath application of ACh, suggesting either a direct inhibitory action of the peptide on the muscle cells or a potentiation of GABA release. In electrophysiological experiments, the reversal potential for the PF1 hyperpolarization was not the same as that for GABA. Thus, PF1 hyperpolarizes Ascaris muscle by a mechanism that does not involve stimulation of GABA release from inhibitory pre-synaptic terminals.

Pilot study of the use of the ECFMG clinical competence assessment to provide profiles of clinical competencies of graduates of foreign medical schools for residency directors. Educational Commission for Foreign Medical Graduates

PURPOSE

To conduct the first of a series of pilot projects of the clinical competence assessment (CCA) of the Educational Commission for Foreign Medical Graduates (ECFMG) in order to provide profiles of clinical competencies of graduates of foreign medical schools for residency directors in the United States and for governments and institutions in other countries.

METHOD AND RESULTS

In September 1992 the first pilot project of the ECFMG CCA was conducted for a program director who wanted to evaluate ten first-year residents in a midwestern U.S. program. The CCA consists of integrated clinical encounters with ten standardized patients, 60 laser videodisc pictorials, and analysis of test items of previously completed ECFMG certification examinations. Profiles of the following clinical competencies were provided to the program director: data gathering (history and physical examination), interviewing and interpersonal skills, diagnosis and management skills, interpretation of diagnostic and laboratory procedures, written communication of information to the health care team, and spoken-English proficiency. The profiles were provided as individual scores compared with mean scores of a reference group of 525 first-year residents who took the CCA at four U.S. assessment centers, and as percentile scores with a range of one standard error of measurement.

CONCLUSION

The individual performance data in this first pilot project were valuable to the program director, who used them to supplement scores on a written examination during the first residency year. The pilot project has shown the ECFMG CCA to be a useful tool for program directors to evaluate applicants and residents who are graduates of foreign medical schools.

Use of NBME and USMLE examinations to evaluate medical education programs

Criteria are presented for determining whether licensure and/or achievement test results should be used as a basis for making various types of comparisons and judgments about medical education programs for program evaluation purposes. United States Medical Licensing Examination (USMLE) examinations and National Board of Medical Examiners (NBME) subject tests are then considered as sources of evaluation data for medical education programs by evaluating these examinations in the light of the proposed criteria. It is concluded that NBME examination and USMLE results may properly be considered one of several tools to use in an evaluation of medical education programs but are not recommended as the sole basis for a judgment of program effectiveness. However, care must be taken to ensure that test score differences are large enough to be real and to have practical significance. Furthermore, changes in curriculum should not be considered or implemented on the basis of NBME/USMLE results unless the changes in test scores are maintained for at least two years. The focus should generally be on inordinately high failure rates rather than on changes in mean class scores. Efforts to develop objective, standardized, and controlled measures of other clinical competencies for national use should be encouraged to minimize the temptation to use USMLE Step 1 and Step 2 scores as the sole basis for comparisons of medical education programs.

ECFMG assessment of clinical competence of graduates of foreign medical schools. Educational Commission for Foreign Medical Graduates

OBJECTIVE

To develop an assessment of clinical competence of graduates of foreign medical schools and to determine the reliability and validity of the assessment and the feasibility of large-scale administration.

DESIGN

The Educational Commission for Foreign Medical Graduates (ECFMG) clinical competence study included (1) clinical encounters with standardized patients to assess history taking, physical examination, and communication skills; (2) laser videodisk pictorials to assess identification and interpretation of diagnostic procedures; (3) written clinical vignettes to assess diagnosis and management skills; and (4) assessment of spoken English. A uniform method of operating the test centers and of training the standardized patients was developed.

SETTING

Medical schools and their primary teaching hospitals and affiliated hospitals.

PARTICIPANTS

Six hundred twenty-four first-year residents, of whom 525 are graduates of foreign medical schools.

MAIN OUTCOME MEASURES

Scores, reliability coefficients, validity measures, feasibility of multisite administration, trends of scores over time, and acceptability by examinees.

RESULTS

The ECFMG clinical competence assessment was conducted at four geographically separate test centers. Reliability coefficients were high (.85) for the integrated clinical encounter and were in a reasonable range (.71 to .82) for all test components. The assessment adds to the predictability of the residents' performance in the hospital over that of current ECFMG certification examinations. Test security was addressed by demonstrating no consistent pattern of change in scores over testing dates. Virtually all examinees thought the assessment was appropriate. Standardized patients were able to assess spoken English accurately.

CONCLUSION

The feasibility of conducting a reliable and valid test of clinical competence for graduates of foreign medical schools was demonstrated for this test population.

Damus-Stansel-Kaye procedure: current indications and results

Between October 1983 and August 1991, 29 consecutive Damus-Stansel-Kaye procedures were performed. Indications for operation included restrictive bulboventricular foramen or subaortic stenosis associated with complex univentricular congenital heart disease (25) and Taussig-Bing heart, subaortic stenosis, or both associated with complex biventricular congenital heart disease (4). Twelve patients underwent concurrent Fontan procedures. Average age at operation was 39.8 months (range, 1 to 132 months). Average outflow tract gradient was 28 mm Hg (range, dynamic to 80 mm Hg). Of the 29 patients, 23 were male and 6 were female. There were three early deaths (10%), two in patients who had a concurrent Fontan procedure. Although there was a trend toward lower age and higher outflow tract gradients in nonsurvivors, these and other factors were not statistically significant predictors of death. Actuarial freedom from cardiac-related death was 88% at 5 years (n = 7). In a mean follow-up of 3.5 years (range, 0.1 to 7.7 years), 3 patients have required reoperation (10%), 2 for aortic valve insufficiency (5 days and 2.75 years) and 1 for a gradient across the anastomosis (5.75 years). Actuarial freedom from reoperation related to a failed Damus-Stansel-Kaye procedure was 90% at 4 years and 75% at 6 years (n = 7).

Technical issues: test application. AAMC

Eighteen questions are posed that the authors believe address the major technical issues involved in the application of standardized patients (SPs). Following each question, selected empirical evidence and commentary are provided in response to the question and as background for further consideration of the issues. The authors conclude that the evidence from this large and systematic knowledge base about SP examinations is encouraging and should be cause for optimism. Moreover, it is noted that far less is known about the measurement properties of conventional procedures for clinical assessment in medical school courses and clerkships. The collective evidence from this extensive SP research base suggests that medical educators should move ahead to realize the benefits of the high-fidelity standardized approach provided by standardized-patient examinations.

Echocardiography in the management of single ventricle: fetal through adult life

Echocardiography contributes to the management of patients with single ventricle by providing an initial comprehensive evaluation in fetal and neonatal life. This allows planning of the initial surgical palliation, usually without the need for cardiac catheterization. Serial surveillance for problems such as subaortic stenosis, valvar insufficiency, or complications of the mitral palliation aids in planning for the timing and type of subsequent surgical procedures. Evaluation of single ventricle size, shape, and mass provides some indication of risk for a Fontan procedure. Transesophageal echocardiography provides an excellent window for the evaluation of the interatrial baffle for shunts, thrombi, or occlusion in the early postoperative period. Later, studies of ventricular and valve function help to direct medical management such as afterload reduction and diuretic therapy.

Nasal airflow asymmetry and the effects of a topical nasal decongestant

Nasal airway resistance (NAR) is normally asymmetrical due to the nasal cycle. The aims of this study were to determine the degree of this asymmetry in healthy subjects and those with acute rhinitis associated with common cold, and to investigate how the administration of a topical nasal decongestant (xylometazoline) influenced the asymmetry in NAR. Unilateral NAR was measured by active anterior rhinomanometry, and was shown to be asymmetrical in both healthy subjects and those suffering with acute rhinitis. The asymmetry in NAR was greater in those with acute rhinitis than in the healthy group, with a ratio between "high" and "low" sides of 2.3:1 in the rhinitis group compared to a ratio of 1.7:1 in the healthy subjects. Administration of a topical nasal decongestant caused a significant decrease in total NAR in both groups and abolished the asymmetry in NAR in the healthy subjects (ratio is 1:1 after decongestion). However, significant asymmetry of NAR was still present in the group with acute rhinitis following the administration of decongestant (ratio is 1.5:1 after decongestion). These findings show that the normal asymmetry in NAR was increased during acute rhinitis associated with common cold, and that in healthy subjects (but not in those with rhinitis) the asymmetry was abolished by administration of a topical decongestant. The results are discussed in relation to nasal sympathetic tone and nasal blood flow.

Modified Fontan procedure in patients less than 4 years of age

BACKGROUND

Initial experience with the modified Fontan procedure in patients < 4 years of age has met with variable success, with early reports showing a high mortality. More recently, improved results with the modified Fontan procedure in younger patients have been achieved. Important advantages of an early Fontan include protection of the pulmonary vascular bed and preservation of ventricular function by reduction in ventricular volume overload and chronic hypoxemia.

METHODS AND RESULTS

From 1982 through May 1991, 90 patients < 4 years of age underwent a modified Fontan procedure. The average age was 29 months (range, 7-48 months), and 30 patients were < 2 years of age. Diagnoses included tricuspid atresia in 36, single ventricle in 45, pulmonary atresia intact septum in seven, and hypoplastic left heart syndrome in two patients. An adjustable ASD was placed in 21. Early mortality was 8.9% (eight of 90), which is only slightly higher than our overall Fontan early mortality of 7.4% in 242 patients. The early mortality in the 30 patients < 2 years of age was 6.7% (two of 30). In a mean follow-up of 38 months (range, 7-89 months), there have been three late deaths (3.7%), and one patient has undergone cardiac transplantation.

CONCLUSIONS

Early Fontan should be undertaken in patients > 6 months old who present with increasing cyanosis provided good hemodynamics are present. A modified Fontan procedure can be performed safely with good clinical results in patients < 4 years old.

Partial biventricular repair of pulmonary atresia with intact ventricular septum. Use of an adjustable atrial septal defect

BACKGROUND

Repair of pulmonary atresia with intact ventricular septum (PA-IVS) is one of the more challenging problems in congenital heart surgery. The hypertrophied but hypoplastic right ventricle is suddenly presented with an increased volume load as the right-to-left shunt is abolished by closure of the atrial septal defect (ASD) as part of definitive repair. We have proposed that a restrictive, adjustable ASD that allows a controlled right-to-left shunt may prevent excessive venous hypertension and allow adequate left-sided filling after biventricular repair of PA-IVS.

METHODS AND RESULTS

From 1982 through 1991, 39 patients presented for definitive repair of PA-IVS. Nineteen of these patients were thought to be suitable candidates for biventricular repair, and the other 20 underwent a modified Fontan procedure. An adjustable ASD was used in 12 of the 19 patients undergoing biventricular repair. Mean age was 24 months (age range, 5-66 months). Two patients had their ASD snared closed in the operating room after coming off bypass. In the other 10 patients, closure of the ASD could not be tolerated at the time of surgery as evidenced by elevation of right atrial pressures by > 15 mm Hg and decreased blood pressure when closure was attempted. Seven patients had their open ASDs closed by the snare device, and one patient had his ASD narrowed in the early postoperative period. One patient underwent delayed closure 16 months after surgery. There was one hospital death.

CONCLUSIONS

The snare-controlled adjustable ASD allows partial biventricular repair of PA-IVS, reducing the risk of low cardiac output and severe venous hypertension in the postoperative period.

Factors influencing survival of patients with heterotaxy syndrome undergoing the Fontan procedure

OBJECTIVES

This study was undertaken to determine those factors that may influence survival in patients with heterotaxy syndrome undergoing the Fontan procedure.

BACKGROUND

The Fontan procedure remains the preferred palliative procedure for patients with heterotaxy syndrome. Although the mortality rate has improved for patients without this syndrome undergoing the Fontan procedure, it remains high for patients with heterotaxy syndrome.

METHODS

The medical records of 20 consecutive pediatric patients with asplenia (n = 12) and polysplenia (n = 8) who underwent the Fontan procedure between January 1, 1986 and December 31, 1990 were reviewed. Anatomic and hemodynamic data were collected, as well as data on types of surgical palliative procedures and on outcome of the Fontan procedure.

RESULTS

There were two early and two late deaths for a total mortality rate of 20% in the patients with heterotaxy syndrome, as compared with 8.5% for the patients without this syndrome who underwent the Fontan procedure during the same time period. Factors that significantly increased the risk of the Fontan procedure in these patients were 1) preoperative findings of greater than mild atrioventricular valve regurgitation, b) hypoplastic pulmonary arteries, and c) mean pulmonary artery pressure greater than or equal to 15 mm Hg after 6 months of age. Systemic and pulmonary venous anomalies coupled with single-ventricle anatomy were not significant risk factors for determining a poor outcome of the Fontan procedure.

CONCLUSIONS

This study suggests that the outcome of the Fontan procedure in patients with heterotaxy syndrome may be improved by early protection of the pulmonary vascular bed, despite the existence of other cardiac anomalies.

Value of acute-phase angiography in the detection of vascular injuries caused by gunshot wounds to the head: analysis of 12 cases

A study of the angiographic findings in consecutive civilian patients with cranial gunshot wounds examined in the acute stage has not been done. Most prior clinical studies have evaluated the findings in survivors in the subacute or chronic stages and have often been of war-time casualties. We determined the clinicoradiologic features of six cases of posttraumatic intracranial aneurysm, vascular occlusion, or arteriovenous fistula caused by penetrating missiles among 12 civilian patients who were examined in the acute posttraumatic stage (within 48 hr of injury) during a 1-year period. Three internal carotid/vertebral artery aneurysms, one external carotid artery aneurysm, one combined aneurysm/arteriovenous fistula of the vertebrobasilar circulation, and one cerebral venous occlusion were identified. The 50% overall prevalence of major vascular lesions in this series of civilian patients with penetrating missile injuries examined in the acute stage suggests these injuries are more common than previously suspected. It may indicate that selective cerebral angiography should be considered in the evaluation of the cranial vascular system of such persons.

Repair of conotruncal abnormalities with the use of the valved conduit: improved early and midterm results with the cryopreserved homograft

Repair of complex cardiac lesions has been facilitated by the availability of valved conduits to reestablish right ventricular to pulmonary artery continuity. From 1977 to June 1991, 148 patients underwent repair with insertion of a conduit. Their mean age was 6.6 years (11 days to 45 years). The diagnosis was transposition of the great arteries with ventricular septal defect and left ventricular outflow tract obstruction in 51, truncus arteriosus in 36, pulmonary atresia with ventricular septal defect in 25, tetralogy of Fallot in 19, double-outlet right ventricle in 10, pulmonary atresia with intact ventricular septum in 6 and atrioventricular canal with pulmonary atresia in 1. A Dacron porcine-valved conduit was used in 37, a homograft conduit in 106 and a nonvalved conduit in 5. There were 13 early deaths overall (8.8%); 8 (22%) of the early deaths occurred in the 37 patients who received a Dacron graft, 4 (3.8%) occurred in the 106 patients who received a homograft and 1 occurred in a patient with a nonvalved Gore-Tex conduit. An additional patient underwent orthotopic heart transplantation in the early postoperative period. In 117 patients operated on from January 1985 to June 1991 the early mortality rate was 2.6% (3 of 117). Among 28 patients receiving a Dacron porcine-valved graft there were two late deaths (7.1%) after a mean follow-up interval of 93 months, and 8 patients required reoperation for conduit obstruction. Among 102 homograft recipients there were two late deaths (1.9%).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of adenoid and tonsil surgery on nasalance

The change in nasalance following adenoidectomy, tonsillectomy and adenotonsillectomy was studied in 44 children. A subjective assessment of each child's naso-pharyngeal airway was made preoperatively based on a questionnaire completed by the parents. There was no significant change in the nasalance of children following adenoidectomy, but there was a significant increase in the nasalance following tonsillectomy (P = 0.02) and after adenotonsillectomy (P = 0.001). There was no relationship between the change in nasalance and the adenoid volume removed at operation. There was good agreement between the parental subjective assessment of the naso-pharyngeal airway and the preoperative nasalance score, with the best correlation in the adenoidectomy group (r = -0.8) and the adenotonsillectomy group (r = -0.7). Nasalance is more closely related to the size of the naso-pharyngeal airway than to the actual adenoid volume, and measurements of nasalance are of no benefit in predicting adenoid volume. Tonsillectomy had a significantly greater effect on nasalance than adenoidectomy, and adenotonsillectomy had the greatest effect. Further studies are needed to relate nasalance to the size of the naso-pharyngeal airway, but it appears to relate well to the subjective assessment of the airway and may be of use in patient selection for surgery.

Ice Flexure Forced by Internal Wave Packets in the Arctic Ocean

Tiltmeters on the Arctic Ocean were used to measure flexure of the ice forced by an energetic packet of internal waves riding the crest of diurnal internal bores emanating from the Yermak Plateau, north of the Svalbard Archipelago. The waves forced an oscillatory excursion of 36 microradians in tilt of the ice, corresponding to an excursion of 16 micrometers per second in vertical velocity at the surface and of 3.5 millimeters in surface displacement. Strainmeters embedded in the ice measured an excursion of 3 x 10(-7) in strain, consistent with ice flexure rather than compression. The measured tilt is consistent with direct measurements of excursions in horizontal current near the surface (12 centimeters per second) and in vertical displacement (36 meters) of the pycnocline 100 meters below the surface.

Partial Fontan: advantages of an adjustable interatrial communication

Systemic venous hypertension after the Fontan procedure is a major cause of mortality and morbidity, accounting for 11 of 16 deaths in our series of 228 Fontan procedures. A partial Fontan with a residual atrial septal defect (ASD) would allow controlled right-to-left shunting to reduce venous pressure and improve cardiac output while maintaining a reduced but acceptable arterial oxygen saturation. This allows complete or graded closure of the ASD after the discontinuation of cardiopulmonary bypass in the operating room or at any time in the postoperative period by exposing the snare under local anesthesia. From 1987 to 1990, 36 patients undergoing the modified Fontan procedure had placement of an adjustable interatrial communication. Indications for placement of an adjustable ASD included increased pulmonary artery pressures, increased pulmonary vascular resistance, reactive airway disease, previously increased or unknown pulmonary vascular resistance, small pulmonary arteries, and borderline ventricular function. Fourteen patients had the adjustable ASD closed at the time of operation, 8 patients underwent narrowing, and 12 underwent closure of the ASD in the postoperative period. Eight patients were discharged with the ASD partially open, and 2 patients underwent delayed closure. The partial Fontan with an adjustable ASD may increase the safety of the Fontan procedure for high-risk groups such as those with increased pulmonary vascular resistance, pulmonary hypertension, and impaired left ventricular function and for infants, who tolerate venous hypertension poorly. The ability to adjust the ASD in stages depending on the hemodynamic response increases flexibility and safety.

The lifespan personal health record

A system for entry of health data in a computer-based patient record by lay individuals is described. The lay user is supported in data entry and data clarification, as well as by system-supported summarization of the data in context to show relationships, highlight sentinel events, and assist in evaluation of alternative decisions and actions as needed.