Cost Savings Analysis of Early Extubation Following Congenital Heart Surgery.

The clinical benefit of early extubation following congenital heart surgery has been demonstrated; however, its effect on resource utilization has not been rigorously evaluated. We sought to determine the cost savings of implementing an early extubation pathway for children undergoing surgery for congenital heart disease. We performed a cost savings analysis after implementation of an early extubation strategy among children undergoing congenital heart surgery at British Columbia Children's Hospital (BCCH) over a 2.5-year period. All patients undergoing one of the eight Society of Thoracic Surgeons (STS) benchmark operations, ASD repair, or bidirectional cavopulmonary anastomosis were included in the analysis (n = 370). We compared our data to aggregate STS multi-institutional data from a contemporary cohort. We estimated daily costs for ICU care, ward care, medications, imaging, additional procedures, and allied health care using an administrative database. Direct costs, indirect costs, and cost savings were estimated. Simulation methods, Monte Carlo, and bootstrapping were used to calculate the 95% credible intervals for all estimates. The mean cost savings per procedure was $12,976 and the total estimated cost savings over the study period at BCCH was $4.8 million with direct costs accounting for 91% of cost savings. Sensitivity analysis demonstrated a mean cost savings range of $11,934-$14,059 per procedure. Early extubation is associated with substantial cost savings due to reduced hospital resource utilization. Implementation of an early extubation strategy following congenital heart surgery may contribute to improved resource utilization.

Exercise and the multidisciplinary holistic approach to adolescent dysautonomia.

AIM: To determine whether an eight-week strength training programme as part of a multidisciplinary approach would minimise symptoms and improve quality of life in patients with dysautonomia. METHODS: Adolescents referred to a tertiary-level cardiology service from May 2014-December 2015 with symptoms of dysautonomia were eligible. Participants completed an exercise test and a quality of life (QoL) questionnaire (PedsQL) prior to the intervention. Participants were asked to complete exercises five times per week. After eight weeks, participants returned for follow-up testing. Parents completed a proxy report of their child's QoL at both time points. RESULTS: A total of 17 participants completed the study protocol with an adherence rate of up to 50%. Post-intervention, QoL scores improved across all levels in the participants [total 65.2 (50.4-74.7) vs 48.9 (37.5-63.0); p = 0.006; psychosocial 65.8 (56.1-74.6) vs 50.0 (41.7-65.8); p = 0.010; physical 62.5 (37.5-76.6) vs 43.8 (25-68.5); p = 0.007] and their parent proxy reports [total 63.5 (48.7-81.3) vs 50.0 (39.3-63.0); p = 0.004; psychosocial 62.1 (52.1-81.3) vs 50.0 (39.6-59.2); p = 0.001; physical 62.5 (51.6-80.0) vs 50.0 (27.5-70.3); p = 0.003]. Treadmill time also improved (9.1 vs 8.0 minutes; p = 0.005). CONCLUSION: Following an eight-week strength training programme, dysautonomia patients report a significant improvement in both their quality of life and endurance time.

Population-based review of tetralogy of Fallot with absent pulmonary valve: is prenatal diagnosis really associated with a poor prognosis?

OBJECTIVES: Tetralogy of Fallot with absent pulmonary valve syndrome (TETAPV) is reported in obstetric literature to have an extremely poor prognosis. We sought to determine the clinical outcome associated with TETAPV and whether prenatal diagnosis confers a poor prognosis. METHODS: All cases of TETAPV diagnosed in British Columbia between 1980 and 2009 were reviewed and grouped according to time of diagnosis, either prenatal or postnatal. The groups were compared with respect to mortality, respiratory problems, number of interventions and functional capacity at last follow-up. RESULTS: Eight and 11 patients were included in the prenatally and postnatally diagnosed groups, with overall long-term survival of 71% and 82%, respectively. There was no significant difference in mortality, frequency of preoperative intubation, number of interventions or functional capacity between groups. CONCLUSION: From a population-based retrospective analysis of TETAPV cases identified over three decades it is concluded that the prognosis for TETAPV is better than that previously reported in the obstetric literature. This information should be used to guide prenatal counseling.

Medications used to manage supraventricular tachycardia in the infant a North American survey.

Supraventricular tachycardia is the most common pediatric arrhythmia, but there is no consensus and little evidence to guide its treatment. We sent a questionnaire to pediatric cardiologists in North America to assess the current practice pattern. Of 1534 surveys mailed, 352 (23%) were returned and 295 (19%) had complete data for analysis. In the acute setting, 11 different medications were chosen. The most commonly used in the infant without preexcitation were digoxin (42%), procainamide (21%), esmolol (13%), propranolol (10%), and amiodarone (8%). In the infant with preexcitation, propranolol (34%), procainamide (23%), esmolol (17%), amiodarone (11%), and digoxin (6%) were used. In the chronic setting, 8 different medications were chosen. The most commonly used in this scenario were digoxin (52%), propranolol (33%), amiodarone (4%), and sotalol (3%). In the infant with preexcitation, propranolol (70%), amiodarone (6%), digoxin (6%), atenolol (6%), and flecainide (5%) were used. Medication choices were influenced by additional electrophysiology training and preexcitation. Digoxin was used less in the setting of preexcitation. There are no comparative trials to explain the different medication choices. Although a number of medications may be efficacious, a randomized clinical trial is needed to offer further guidance.

Diagnosis of fetal ductus arteriosus aneurysm: importance of the three-vessel view.

OBJECTIVE: To present four cases of ductus arteriosus aneurysm (DAA) detected by fetal echocardiography and highlight the value of the three-vessel view in the diagnosis of DAA. METHODS: In addition to the standard fetal echocardiographic views, we examined the three-vessel view in four cases of DAA. The three-vessel view was achieved by sliding the transducer cranially from the four-chamber plane toward the fetal upper mediastinum to demonstrate cross-sections of the main pulmonary artery, the ascending aorta and superior vena cava arranged in a straight line from the left anterior to the right posterior aspect of the mediastinum. DAA was diagnosed when there was a tortuous ductus arteriosus with a dilation that protruded leftward of the aortic arch. CASE SERIES: In the first case, an insulin-dependent diabetic woman underwent fetal ultrasound examination at 36 weeks' gestation showing right-to-left cardiac disproportion and bidirectional flow in the aorta and main pulmonary artery (PA). The three-vessel view showed a dilated ductus arteriosus (DA) which was stenosed at its distal end. In the second case, a woman had fetal ultrasound scans at 38 and 39 weeks' gestation for suspected intrauterine growth restriction and oligohydramnios. The scans identified an abnormal aortic arch and the three-vessel view showed an elongated vascular structure at the distal end of the PA, which was the DAA. In the third case, a woman with a high-risk obstetric history had multiple scans showing an abnormal PA to aorta relationship, with an apparent 'kink' in the PA. The three-vessel view clarified that this was the DAA. In the fourth case, a woman was scanned because of a 3-kg weight gain in 1 week. The fetal ultrasound scan showed moderate polyhydramnios with normal fetal growth and normal intracardiac anatomy and flow, and the three-vessel view demonstrated a large DA. In each of these cases, the DAA appeared to have occurred in isolation with non-specific clinical findings. CONCLUSION: We advocate the use of the three-vessel view, in conjunction with the standard echocardiography views currently employed, to assist in the diagnosis of DAA.

Myocardial contractility in premature neonates with and without patent ductus arteriosus.

Controversy exists as to whether a hemodynamically significant left-to-right shunt due to a patent ductus arteriosus (PDA) affects ventricular contractility. Load-dependent indices such as ejection fraction and shortening fraction have traditionally been used to assess contractility, but the relationship between the rate-corrected velocity of fiber shortening (MVCFc) and wall stress may be more suitable, as it is a preload-independent, afterload-adjusted method of assessing ventricular contractility. Age-related differences have been established for these variables in normal adults and children and it has been recommended for use in the premature neonate. The study was performed to assess left ventricular contractility in premature neonates with a significant left-to-right shunt due to a PDA. Using echocardiography, we measured the relationship of MVCFc to stress at peak systole (SPS) in two groups of premature infants. Group 1 consisted of 15 controls (680-1495 g, 25-32 weeks' gestation), and Group 2 of 15 neonates with hemodynamically significant PDA (840-1635 g, 26-33 weeks' gestation). In both groups, MVCFc was linearly and inversely related to SPS ( p < 0.001). The regression equations were as follows: Group 1, MVCFc = -0.0153SPS + 1.70 ( R(2) = 0.68); and Group 2, MVCF = - 0.019SPS + 1.89 ( R(2) = 0.76). There was no significant difference in the relationship between the two groups, but their slopes were significantly steeper and had a higher Y-intercept than the relationship we previously reported for older children. This preliminary study establishes the normal MVCFc/SPS relationship in the premature neonate (25-33 weeks' gestation) and suggests that premature infants function at a higher resting contractile state than older children. A hemodynamically significant PDA has no effect on contractility. These data will be useful in assessing left ventricular contractility in premature neonates with other types of ventricular loading and noncardiac stress.

Balloon angioplasty of right ventricular outflow tract conduits.

Palliation of complex congenital heart disease, requiring reconstruction of the right ventricular outflow tract (RVOT), is standard practice. Survival of the homograft is a limiting factor. We examined the role of balloon angioplasty (BAP) in prolonging conduit life. Twelve patients underwent 15 BAP procedures between February 1989 and October 1997. The median age at conduit insertion was 28 months with detection of a significant echo gradient 42 months later. Calcification of homografts, with attendant obstruction and valve dysfunction, was present in all patients. BAP was performed within 1 month of echocardiography and reduced the gradient from a median of 57 to 38 mmHg (p < 0.0005). Echocardiographic follow-up showed persistent gradients (median 68 mmHg) and 11/12 patients went on to conduit replacement after BAP. Only one patient had replacement deferred as a result of BAP. Complications requiring intervention occurred in 20% of the procedures and included bleeding and an unusual balloon fracture. Although BAP can reduce the pressure gradient across the RVOT conduit, the effect is transient and the delay of surgery is not due to improved hemodynamic function. Approximately 10% of cases will benefit from BAP alone, but given the high rate of complications, we do not recommend this procedure as a means of prolonging conduit life.

Effect of body position on measurements of diffusion capacity after exercise.

BACKGROUND: Pulmonary diffusing capacity for carbon monoxide (D1co), alveolar capillary membrane diffusing capacity (Dm), and pulmonary capillary blood volume (Vc) are all significantly reduced after exercise. OBJECTIVE: To investigate whether measurement position affects this impaired gas transfer. METHODS: Before and one, two, and four hours after incremental cycle ergometer exercise to fatigue, single breath D1co, Dm, and Vc measurements were obtained in 10 healthy men in a randomly assigned supine and upright seated position. RESULTS: After exercise, D1co, Dm, and Vc were significantly depressed compared with baseline in both positions. The supine position produced significantly higher values over time for D1co (5.22 (0.13) v. 4.66 (0.15) ml/min/mm Hg/l, p = 0.022) and Dm (6.78 (0.19) v. 6.03 (0.19) ml/min/mm Hg/l, p = 0.016), but there was no significant position effect for Vc. There was a similar pattern of change over time for D1co, Dm, and Vc in the two positions. CONCLUSIONS: The change in D1co after exercise appears to be primarily due to a decrease in Vc. Although the mechanism for the reduction in Vc cannot be determined from these data, passive relocation of blood to the periphery as the result of gravity can be discounted, suggesting that active vasoconstriction of the pulmonary vasculature and/or peripheral vasodilatation is occurring after exercise.

The evolution of ductus arteriosus treatment.

The treatment of patent ductus arteriosus (PDA) has evolved over the years. We reviewed 231 non-premature children (group 1) undergoing surgical closure of a PDA between January 1985 and December 1997, and 30 children (group 2) undergoing transcatheter closure from May 1995 to December 1998. The median age and weight at operation in group 1 were 13 months (range, 0.5-174 months) and 9.5 kg (range, 1.9-49.7 kg), respectively. There was one intra-operative death (0.4%) secondary to hemorrhage. Immediate extubation was performed in 208 patients (90%). Intra-operative chest tube use decreased from 73.3% to 10% between the 1985-88 and 1996-97 periods (P < 0.001). Postoperative pneumothoraces occurred in 33/131 (25%) patients with only one patient (0.7%) requiring drainage. Eleven patients had complications including wound infection in four, vocal cord paralysis in three, and left pulmonary artery stenosis in one. The median length of stay (LOS) was 5 days (range, 2-43 days). Follow-up echocardiogram was performed in 146/230 patients (63%) and revealed a residual PDA in six (4%); two being re-ligated, two remaining clinically insignificant, and two spontaneously resolved at 7 and 28 months follow-up. The remaining 84 patients had no clinical signs of a residual PDA. In group 2, where a transcatheter coil occlusion technique was used, the median age and weight at procedure were 31 months (range, 9-320 months) and 14.9 kg (range, 9-69.7 kg), respectively. Vascular complications occurred in four patients (13.3%). One patient developed hemolysis and hemoglobinuria requiring hospital admission. Four patients required a second intervention. At the most recent echocardiographic assessment, four patients (13.3%) had a residual PDA.

Coil occlusion of the patent ductus arteriosus: lessons learned.

PURPOSE: To review the clinical outcomes of catheter-directed coil occlusion (coil occlusion) of persistently patent ductus arteriosus (PDA) at a pediatric tertiary care hospital. METHODS: A retrospective review of all patients referred to the Cardiac Catheterization Laboratory for coil occlusion at our institution was performed. Twenty-one consecutive patients (12 female) underwent coil occlusion and follow-up between May 1995 and December 1997. We undertook PDA occlusion if: (a) the PDA narrowed to less than 4 mm on echocardiogram and (b) the minimum body weight was approximately 10 kg. Standard right and retrograde left heart catheterization was performed, followed by coil occlusion. Color-flow mapping (CFM) was used intra-procedurally to confirm occlusion of the PDA with a follow-up study several weeks later. RESULTS: The median age and weight of the patients were 33 months and 13.2 kg, respectively. Fourteen patients received one coil, with six requiring a second coil and one requiring multiple coils. Initial follow-up was at a median of 2.4 months. At latest follow-up, 2 patients still have persistent flow at the ductal level. The coils were deployed without complication or embolization. CONCLUSIONS: A review of our first 21 cases demonstrated three important lessons: (1) the maximum diameter of the PDA suitable for coil occlusion is approximately 3 mm; (2) CFM must show complete obliteration of flow in the catheterization lab in order to ensure occlusion of the PDA at follow-up; and (3) the Jackson detachable system allows for precise placement of the coil, often within another coil.

The effect of repeat exercise on pulmonary diffusing capacity and EIH in trained athletes.

PURPOSE: The purpose of this study was to determine the effects of repeated heavy exercise on postexercise pulmonary diffusing capacity (DL) and the development of exercise induced arterial hypoxemia (EIH). METHODS: 13 endurance-trained, male athletes (age = 27+/-3 yr, height = 179.6+/-5.0 cm, weight = 71.8+/-6.9 kg, VO2max = 67.0+/-3.6 mL x kg(-1) x min(-1) performed two consecutive, continuous exercise tests on a cycle ergometer to VO2max, separated by 60 min of recovery. Arterial oxygen saturation (%SaO2) was measured via ear oximetry, and resting DL was measured and partitioned by the single-breath method, before exercise and 60 min after each exercise bout. RESULTS: No significant differences resulted in VO2max, VE, peak heart rate (HR), or breathing frequency between exercise bouts (P > 0.05). There was a small but significant decrease (454-446 W; P < 0.05) in peak power output in the second test. %SaO2 decreased from resting values during both exercise tasks, but there was no difference between the minimum saturation achieved in test 1 (91.4) or test 2 (91.6; P > 0.05). After the initial exercise bout, significant decreases (P < 0.05) occurred in DL (11%), membrane diffusing capacity (DM) (11%) and pulmonary capillary volume (VC) (10%). Further decreases occurred in DL (6%; P < 0.05), DM (2%; P > 0.05), and VC (10%; P < 0.05) after the second exercise bout. CONCLUSIONS: These observations question the meaning of post exercise measurements of pulmonary diffusion capacity, and its components, relative to pulmonary gas exchange and pulmonary fluid accumulation during exercise. The fact that there was no further change in %SaO2 after the second test suggests that if any interstitial edema developed, it was of no clinical significance; alternatively, the changes in DL(CO) may be related more to redistribution of blood than the development of pulmonary edema.

The time course of pulmonary diffusing capacity for carbon monoxide following short duration high intensity exercise.

We investigated the time course of changes in post-exercise pulmonary diffusing capacity for carbon monoxide (DLCO), membrane diffusing capacity (DM), and pulmonary capillary blood volume (VC) in highly trained (HT), moderately trained (MT) and untrained (UT) male subjects (n = 8/group). Subjects were assigned to groups based on their aerobic capacity from a preliminary VO2max test (HT > or = 65, MT = 50-60, UT < or = 50 ml x kg(-1) x min(-1)). Resting (BASE) DLCO, DM and VC were obtained, then subjects cycled to fatigue at the highest workrate attained during the preliminary tests. Diffusion measurements were then made at 1, 2, 4, 6 and 24 h. DLCO was depressed at 1 h, lowest at 6 h and approached BASE values at 24 h in all groups. The DLCO change was paralleled by a change in VC. Alterations to VC were similar between groups except at 24 h where MT and HT subjects had returned to BASE while UT did not. DM was significantly lower than BASE at 1, 2, 4, and 6 h, and was similar between groups. The changes in DLCO post-exercise appear to be primarily due to a decrease in VC. Comparable diffusion decrements were observed in all subjects. The results of this study suggest that post-exercise alterations in DLCO, DM and VC are not related to aerobic capacity.

Intermediate follow-up of right ventricular outflow tract reconstruction with allograft conduits.

BACKGROUND: Allograft conduits are among many varieties of material used for right ventricular outflow tract reconstruction. They invariably need to be replaced due to growth of the patient or conduit failure. METHODS: From June 1984 to June 1996, a total of 76 patients underwent reconstruction of the right ventricular outflow tract with an allograft conduit: 51 aortic and 25 pulmonary. The median age, weight and conduit size at surgery were 37 months (range, 0.2 to 228 months), 12.4 kg (range, 2.9 to 61.4 kg), and 17 mm (range, 8 to 26 mm), respectively. RESULTS: The hospital mortality was 5.3% (4 of 76 patients) and 2 patients died at 9 and 78 months follow-up. The median follow-up was 61 months (range, 2 to 132 months). Reoperation was necessary in 22 patients (28.9%) at a median interval of 50.5 months (range, 3 to 109 months) and the median conduit size was 21 mm (range, 12 to 23 months). There was no mortality. Freedom from reoperation at 64 months was 49.5% for conduits 15 mm and smaller, and 73.3% for conduits 16 mm and larger. Analysis by age shows freedom from reoperation at 64 months of 49.4% and 74.5% for patients younger than and older than 2 years, respectively. At 54 months there was no statistical difference in freedom from reoperation between pulmonary and aortic allografts. CONCLUSION: Right ventricular outflow tract reconstruction with allograft conduits results in a high reoperation rate at 4 years but provides significantly longer freedom from reoperation with conduits larger than 15 mm or in patients over 24 months of age.

Risks of repeat sternotomy in pediatric cardiac operations.

BACKGROUND: Repeat sternotomy has been associated with increased perioperative risks. METHODS: We reviewed 165 patients undergoing 192 repeat sternotomies between January 1985 and January 1997 (group 1) and a control group of 184 patients (group 2). The operations in group 1 were valve procedures in 94 patients, Fontan procedure in 46, ventricular septal defect closure in 10, pulmonary arterioplasty in 17, and others in 25; in group 2 ventricular or atrial septal defect closure in 120 patients, tetralogy of Fallot repair in 26, valve procedures in 16, bidirectional Glenn anastomosis in 7, repair of transposition of the great arteries in 7, pulmonary arterioplasty in 4, and others in 4. RESULTS: The hospital mortality was 2.6% in group 1 and 3.8% in group 2. Cardiac laceration occurred in 10 of 192 patients (5.2%), requiring emergent femorofemoral bypass in 6 patients. Two patients sustained an air embolism that was successfully treated with a hyperbaric chamber. Median total blood loss and requirements were not significantly different between the two groups. The length of stay in the intensive care unit and in the hospital were 4 days (range, 1 to 80 days) and 11 days (range, 1 to 135 days) in group 1, and 2 days (range, 1 to 87 days) and 7 days (range, 1 to 131 days) in group 2 (p < 0.02 and p < 0.002, respectively). The rate of complications was not significantly different in group 1 versus group 2. Overall survival was 97% (group 1) and 95% (group 2) at 120 months' follow-up (not significant). CONCLUSIONS: With careful surgical technique and judicious use of femorofemoral bypass, the risk of repeat sternotomy is minimized.

Is surgical closure of patent ductus arteriosus a safe procedure in premature infants?

Despite indomethacin therapy, many premature infants require surgical closure of their patent ductus arteriosus (PDA). Between January 1985 and December 1997, 176 premature infants underwent surgical closure of PDA by vascular clip after failure of medical treatment. The median gestational age and birth weight were 26 weeks (range 23-36 weeks) and 847.5 g (range 400-2300 g), respectively. The median age at diagnosis and at surgery was 4 days (range, 1-37) and 21 days (range, 4-60) respectively. The median weight at surgery was 982.5 g (range 475-2740 g). Of these infants, 168 (95%) were intubated prior to surgery and the median time to extubation was 21 days (range 1-273 days). There were no operative deaths but 11 infants (6.4%) died from complications of prematurity (sepsis, bronchopulmonary dysplasia and pulmonary hemorrhage). The frequency of chest tube insertion at surgery decreased from 41.7% to 10% between the 1985-88 and 1996-97 periods (P<0.01). Three infants (1.7%) developed vocal cord paralysis directly related to the position of the vascular clip. Echocardiography confirmed PDA closure in 43 infants (24.4%) while the remaining 133 had no clinical signs of PDA. Surgical closure of PDA by vascular clip carries a very low morbidity in premature infants.

Back pain and spinal changes in microgravity.

We believe that investigations into back pain and spinal changes in microgravity will contribute significantly to our knowledge and understanding of factors that cause back pain and the influence of spinal cord distraction on sensory and autonomic dysfunction. This information may have clinical implications for the treatment and rehabilitation of patients with spinal cord injury, for the care of patients during and after corrective spinal surgery, for the care and treatment of patients with chronic pain syndromes, and may potentially provide us with the opportunity to learn more about demyelinating diseases.

Physiological profiles of the Canadian Olympic Soccer Team.

Physiological profiles of elite athletes are becoming increasingly important both for the sport scientist and coach, primarily to effectively develop training programs and to use as a motivational tool in the pursuit of excellence. Descriptive profiles were developed on 16 aspirants of the Canadian Olympic Soccer team during their training program at U.B.C. Selected strength measures were obtained from a Cybex II isokinetic dynamometer at 30 degrees sec-1. Metabolic variables were derived utilizing a Beckman metabolic cart interfaced with a Hewlitt Packard 3052A data acquisition system. Protocols involved were the following: VO2max (initial velocity 8.05 km X h-1, greater than 0.805 km X min-1); Anaerobic speed test (AST) (20% grade, 12.8 km X h-1). the nonlinear increase in excess CO2 was utilized to determine the anaerobic threshold (AT). (Table: see text). Recommendations emphasized maintenance of low body fat, increasing maximal aerobic power by approximately 10% and creating a hams/quads ratio of 60%. Also, a nutritional survey and periodic evaluation of iron status is necessary for the athletes.