Design principles for engaging and retaining virtual citizen scientists.

Citizen science initiatives encourage volunteer participants to collect and interpret data and contribute to formal scientific projects. The growth of virtual citizen science (VCS), facilitated through websites and mobile applications since the mid-2000s, has been driven by a combination of software innovations and mobile technologies, growing scientific data flows without commensurate increases in resources to handle them, and the desire of internet-connected participants to contribute to collective outputs. However, the increasing availability of internet-based activities requires individual VCS projects to compete for the attention of volunteers and promote their long-term retention. We examined program and platform design principles that might allow VCS initiatives to compete more effectively for volunteers, increase productivity of project participants, and retain contributors over time. We surveyed key personnel engaged in managing a sample of VCS projects to identify the principles and practices they pursued for these purposes and led a team in a heuristic evaluation of volunteer engagement, website or application usability, and participant retention. We received 40 completed survey responses (33% response rate) and completed a heuristic evaluation of 20 VCS program sites. The majority of the VCS programs focused on scientific outcomes, whereas the educational and social benefits of program participation, variables that are consistently ranked as important for volunteer engagement and retention, were incidental. Evaluators indicated usability, across most of the VCS program sites, was higher and less variable than the ratings for participant engagement and retention. In the context of growing competition for the attention of internet volunteers, increased attention to the motivations of virtual citizen scientists may help VCS programs sustain the necessary engagement and retention of their volunteers.

One-stage midline unifocalization and complete repair in infancy versus multiple-stage unifocalization followed by repair for complex heart disease with major aortopulmonary collaterals.

BACKGROUND: Patients with pulmonary atresia, ventricular septal defect, and major aortopulmonary collateral arteries have traditionally required multiple unifocalization staging operations before undergoing complete repair. Recently, the feasibility of a single-stage unifocalization and repair was demonstrated by Hanley. In this report, we describe our experience with each approach. METHODS AND RESULTS: Since 1989, 11 of 12 patients with pulmonary atresia, ventricular septal defect, and major aortopulmonary collateral arteries have undergone complete surgical correction. The first seven patients were subjected to staged bilateral unifocalizations, with repair being achieved in six (group I). The last five patients have undergone a single-stage midline unifocalization and repair via a sternotomy (group II). Four of these were infants (2 weeks to 9 months) and one was 13 years old. All patients in group I had tetralogy of Fallot, whereas in group II three patients had tetralogy of Fallot, one patient had double-outlet right ventricle, and one patient had complete atrioventricular canal and transposition. In group I, the median age at the first operation was 43 weeks. Complete repair was performed at a median age of 3.5 years, with a mean number of 3.3 operations required. In group II, only one operation was required to achieve complete repair at a median age of 28 weeks. The postoperative right ventricular/left ventricular pressure ratio was 0.49 in group I and 0.45 in group II. One intraoperative death and one late death occurred in group I and no early or late deaths in group II. Currently, four patients in group I and all five patients in group II are alive and well. CONCLUSIONS: Early intervention with both surgical approaches can lead to complete biventricular repair in most patients. Because the single-stage midline unifocalization and repair can achieve a completely repaired heart in infancy with one operation, it is currently our approach of choice.

Charles Drew and the origins of deep hypothermic circulatory arrest.

Convinced that the high risk of operation using the early heart-lung machines was due to a toxic effect of the oxygenators in use in the 1950s, Charles Drew of Westminster Hospital in London devised a circulatory support system in which the patient's own lungs functioned as the oxygenator. With this support, body temperature was reduced to the point where circulatory arrest could be tolerated for the time required to carry out the intracardiac operation. He used only this technique for the rest of his surgical career, a period of 22 years. We have attempted to record how this came to pass and to describe the qualities of this man that led him to be original and creative.

The Holmes heart: historic associations and pathologic anatomy.

In 1824, Andrew F. Holmes, later to become the first Dean of the Medical Faculty of McGill University, published the autopsy findings of a 21-year-old man who had died with chronic cyanosis and congestive heart failure. Autopsy revealed the first documented case of single ventricle. Reinspection and detailed photographs published for the first time show absence of the sinus (body or inflow tract) of the morphologically right ventricle (RV) and hence a single (unpaired) morphologically left ventricle (LV), double-inlet LV, infundibular outlet chamber (IOC), and normally related great arteries, with the pulmonary artery arising from the IOC and the aorta from the single LV. In view of its rarity, William Osler urged Maude Abbott to republish this case, which she did in 1901. Republication of the Holmes heart catalyzed the career of Maude Abbott, who then proceeded to become the world's authority on congenital heart disease until her death in 1940.

Institutional experience with a protocol of early primary repair of double-outlet right ventricle.

BACKGROUND: Our institution has adopted a protocol of primary repair for all patients with double-outlet right ventricle. METHODS: Since May 1989, 24 consecutive neonates and infants with double-outlet right ventricle and atrioventricular concordance (median age, 4 months) underwent anatomic biventricular repair. One patient (4%) received prior pulmonary artery banding but was still repaired as a neonate at 22 days of age. Twelve patients had a subaortic ventricular septal defect (VSD), 5 patients a subpulmonary VSD, 3 patients doubly committed VSD, and 4 patients a noncommitted VSD. Sixty-nine of 72 associated lesions were repaired simultaneously. Four types of repairs were used: intraventricular rerouting in 16 patients, arterial switch operation with VSD closure into the pulmonary artery in 4 patients, Rastelli-type repair with extracardiac conduit in 3 patients, and the Damus-Kaye-Stansel repair with concomitant repair of aortic arch obstruction in 1 patient. Ventricular septal defect enlargement was necessary in 15 patients. Repair of subpulmonary stenosis and of subaortic stenosis was carried out in 13 and 4 patients, respectively. Three patients underwent simultaneous repair of aortic arch obstruction with no mortality. Two of the patients with noncommitted VSD had simultaneous repair of complete atrioventricular canal and repair of severe pulmonary venous obstruction. RESULTS: The perioperative mortality was 8% (2 patients, and there was one late death (4%). Two patients (9%) underwent early successful reoperations (5 and 8 weeks postoperatively). The two reoperations were for residual VSD (1 patient) and severe mitral regurgitation (1 patient). All 21 survivors are alive at a mean follow-up of 40 months (range, 7 months to 6 years). The estimated 5-year actuarial survival is 88%, with no deaths after 2 months postoperatively. Ninety-five percent of long-term survivors have no restriction of physical activities because of cardiac status and are receiving no cardiac medications. CONCLUSIONS: An institutional protocol of early anatomic biventricular repair of double-outlet right ventricle in infants and neonates achieves excellent survival, making palliative operations unnecessary. Associated lesions should be repaired simultaneously. The complexity of these malformations requires a highly individualized and flexible surgical approach.

The management of chylothorax/chylopericardium following pediatric cardiac surgery: a 10-year experience.

We reviewed the management of 25 cases of chylothorax/chylopericardium (CT/CP) in 24 patients (9 females, 15 male; 3 days to 11-years-old) following 1605 cardiothoracic procedures (incidence of 1.5%) between January 1984 and December 1993 at our institution. The surgical procedures preceding the occurrence of lymph leak included ligation of patent ductus arteriosus (6 patients), coarctation/double aortic arch repairs (3), complex intracardiac repairs (11), and systemic to pulmonary shunts (5). There were 3 CPs and 22 CTs. All of the patients were initially treated nonsurgically with diet modification using either total parenteral nutrition (TPN) or enteral low fat solid food or enteral elemental diet supplemented with intravenous lipid emulsion. Twenty-one cases (84%) responded to conservative therapy. Of those, 15 had TPN as the initial treatment; the average duration of lymph leak was 13.7 (range 7 to 30) days and the average maximal lymph leak was 39.4 (range 15 to 130) mL/kg per day. The other six cases had low-fat enteral diet as the initial treatment, four resolved completely. Two with high-central venous pressure had to be switched to TPN prior to complete resolution. The average duration of lymph leak in this subgroup was 30 (range 12 to 56) days with the average maximal lymph leak was 30.1 (range 8.5 to 59) mL/kg per day. Excluding these two cases, the average lymph leak of the rest of the group was very compatible to the TPN group of 15 days. Lymphocytopenia and hyponatremia were frequently seen during CT/CP (47.6% and 43%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Successful repair of recurrent coarctation after neonatal heart transplantation.

Neonatal orthotopic heart transplantation is an attractive primary surgical therapy for severe uncorrectable congenital heart defects such as variants of the hypoplastic left heart syndrome. Aortic arch reconstruction is frequently required to repair the hypoplastic aortic arch and the coarctation at the time of graft implantation. Residual coarctation of the aorta after neonatal heart transplantation for such a condition has satisfactorily been treated with percutaneous balloon dilatation. We describe the successful surgical repair of a recurrent coarctation of the aorta via a sternotomy in a 2-year-old patient who had previously undergone neonatal orthotopic heart transplantation. Postoperative periodic investigations have not shown any evidence of obstruction across the site of the primary end-to-end anastomosis.

The origins of endotracheal ventilation.

Physiologists could keep animals alive with an open chest long before surgeons set about doing the same thing in patients. Why was there not an orderly transfer of knowledge and technique?

The ductus and the coarctation.

After Robert E. Gross' historic ligation of a persistent ductus arteriosus in August 1938, it took 6 years before the first coarctation was operated on. Gross initiated experimental procedures directed at repair of coarctation even before the ductal operation had been performed. He had the desire, the drive, and the determination. Why the delay that allowed Clarence Crafoord to perform the first coarctation repair in October 1944?

Theodore Tuffier's attempt at cardiac resuscitation.

Theodore Tuffier, in 1898, incised a dying patient's chest on the wards of La Pitie Hospital and carried out manual cardiac massage. This act, based on animal experimentation, led to the first published surgical exposure of the unwounded human heart and illustrates the determination and creativity of a remarkable pioneer.

Arthur Vineberg and the internal mammary artery implantation procedure.

A summary of Vineberg's experimental pioneer work on the internal mammary artery implant is presented, together with comments on the clinical series and the difficulty in evaluating the results before the era of coronary angiography. A plea is made for recognition of the fact that an implanted internal mammary artery can arborize and communicate with the native coronary arteries.

Cardiac transplantation: treatment for cardiogenic shock.

Eighty-six patients received orthotopic cardiac transplants at the Royal Victoria Hospital in Montreal between 1985 and 1989. Of these, 16 mortally ill, being sustained in hospital by the intravenous administration of inotropic agents (15 patients [94%]) or intra-aortic balloon counterpulsation (6 [38%]). There was one early death (at 7 days), for a death rate of 6.3% (versus 8.6% for the 70 "elective" transplants). Two others died of delayed infection: one of viral hepatitis at 6 weeks, and one of pneumonia due to Pneumocystis 4 months after transplantation. The other 13 patients are alive and well 12 to 66 months postoperatively. Nine have returned to their preoperative work, three have decreased activity levels but are functioning well, and one is retired.

Norwood operation for univentricular heart with subaortic stenosis in the neonate.

In the setting of a single ventricle, subaortic stenosis may be enhanced by pulmonary artery banding and may later contraindicate a Fontan operation. The Norwood operation may prove a preferable alternative in some infants as a preparatory procedure. We have successfully used this procedure as the initial operation to palliate a newborn with tricuspid atresia, transposition of the great arteries, coarctation, and severe arch hypoplasia secondary to a restrictive bulboventricular foramen.

Sternotomy after muscle flap repair of sternal osteomyelitis and mediastinitis.

A 61-year-old man who had undergone aortocoronary bypass developed sternal osteomyelitis and mediastinitis which required sternal debridement and muscle flap interposition. Two years later the midline incision was used for an orthotopic heart transplantation. No major technical difficulties were encountered at the time of transplantation.

Pericardial effusion after cardiac surgery in children and effects of aspirin for prevention.

Seventy-four children aged 0.3 to 21.4 years (median 4.0) were followed echocardiographically on days 4, 7, 14 and 28 (+/- 2 days) after cardiac surgery to evaluate the incidence of postoperative pericardial effusion, to identify the patients at greatest risk of developing an effusion and to evaluate the use of aspirin as prophylaxis against pericardial effusion. Pericardial effusion was graded relative to the size of the aortic root from grade 0 (no effusion) to grade 5 (larger than the aortic root dimension). Patients were randomly divided into 2 groups: group 1 (32 patients) received aspirin 60 mg/kg/day for 7 days starting on the third postoperative day; group 2 (42 patients) received no aspirin. Forty-eight patients (65%) developed an effusion during the study period, 3 required pericardiocentesis and 1 died of tamponade. All patients with tamponade had a grade 4 effusion. Age or type of operation did not alter the cumulative incidence of significant effusion. No patient with a grade 0 effusion on the first echocardiogram developed a grade 4 or 5 effusion. Results in groups 1 and 2 were similar. Pericardial effusions are common in the first month after cardiac surgery. Patients with no effusion in the immediate postoperative period appear to be at lesser risk of developing a grade 4 effusion in the first month after operation. Finally, aspirin prophylaxis against postoperative pericardial effusions did not significantly alter the outcome in this small series of patients.

Delayed sternal closure: a lifesaving maneuver after early operation for complex congenital heart disease in the neonate.

Early repair of complex congenital heart malformations may lead to life-threatening respiratory and hemodynamic embarrassment on sternal closure. To avoid a fatal outcome in these situations, we postponed sternal closure in nine critically ill neonates by suturing silicone elastomer sheeting to the skin edges. This maneuver, in a setting of optimal inotropic and ventilatory support, allowed eight of the nine neonates to survive. The mean age at operation was 10.2 days (range 3 to 31). The mean preoperative weight was 3004.4 gm (range 1550 to 3780). The sternal wound was protected with an impervious silicone elastomer sheeting for a mean of 5.6 days (range 2 to 12). There was no instance of wound infection. The judicious application of this technique after operations for complex congenital heart disease can provide the necessary compliance vital for immediate cardiopulmonary performance and ultimate survival.

Congenital abdominal aortic aneurysm.

The authors report the extremely rare occurrence of a congenital abdominal aortic aneurysm, 6 cm in diameter, found in a 1-month-old infant. Prenatal ultrasonography at 34 weeks' gestation had shown the aneurysm, which at that time was interpreted as a renal cyst. At operation, an 8-mm polytetrafluoroethylene tube graft was interposed between the infrarenal aorta and the bifurcation. Cardiopulmonary bypass facilitated operative management by permitting return of blood lost and by maintaining body temperature. In a review of the literature, the authors could not find any report of a neonatal aneurysm of this magnitude. Regrettably, the cause of this true aneurysm remains obscure.

Intermediate results of the arterial switch repair. A 20-institution study.

A total of 466 neonates with transposition of the great arteries, all less than 15 days of age, have been entered into a 20-institution study between Jan. 1, 1985, and June 1, 1987. Seventy-three percent were less than 48 hours old when entered into the study. Two hundred twelve of these underwent an arterial switch repair, and the 1-week, 1-year, and 2 1/2-year survival rates were 82%, 79%, and 78%, respectively. The usual coronary anatomy was present in 67% of the patients. The arterial switch repair was performed in 16 of the institutions. Six among these were shown to be "low-risk" institutions, with the prevalence of the demographic and surgical variables seeming to be the same in these as in the other institutions. The 1-week, 1-year, and 2 1/2-year survival rates after the arterial switch repair in low-risk institutions for simple transposition were 96%, 91%, and 90%, respectively; for transposition with ventricular septal defect they were 84%, 83%, and 83%. Only older age at operation (over 14 days of age), in the case of simple transposition, and transposition with ventricular septal defect were risk factors for death in these six institutions. Among the patients as a whole, freedom from reoperation for pulmonary outflow obstruction at 1 week and 1 year was 99% and 89%, respectively. A previous pulmonary artery banding and, possibly, one institution were identified as risk factors for reoperation. Inferences: In low-risk institutions, the arterial switch repair can be accomplished with good early results, which suggests the possibility that the late results will be better than after the atrial switch repair. Since young age was not a risk factor for the arterial switch repair of transposition and ventricular septal defect, this type of repair for this anomaly, as well as for simple transposition, may be more advantageously performed early in life than at 2 to 3 months of age.