Pulmonary Artery Banding in Post-tricuspid Congenital Cardiac Shunting Defects with High Pulmonary Vascular Resistance.

Reports of "treat and repair" of cardiac shunting lesions with inoperably high pulmonary vascular resistance (PVR) mostly concern pre-tricuspid defects; post-tricuspid lesions are different. We report our experience with pulmonary artery (PA) banding ± targeted pulmonary hypertension medications in five patients with a large VSD and inoperably high PVR, and review previous reports of PA banding with post-tricuspid defects. Three of our 5 patients had mean PAP > 50 mmHg after banding and no or only a transient fall in PVR. Two patients had mean PAP < 50 mmHg and lower PVR after banding; they had closure of their VSDs but have since had a progressive increase in PVR (follow-up after closure, 3.5 and 7.7 years). Previous reports have also documented difficulty in achieving sufficient band gradient. Of previously reported patients, only one became operable only after banding and targeted therapy, and was repaired; follow-up after repair was short-term (16 months). Our and previous experience demonstrate the difficulty in placing a PA band sufficiently tight to substantially reduce PA pressure. Reported attempts to "treat and repair" post-tricuspid defects are few and have met with limited success, and we found that PVR may increase significantly over time after repair. But more information is needed. Accurate interpretation of experience with "treat and repair" requires: careful characterization of the pulmonary circulation prior to "treating"; considering spontaneously reversible factors at pre-treatment catheterization before ascribing reduction in PVR to medical therapy; and long-term observation of PVR in patients who have had defect closure.

Systemic Ventricular Dysfunction Between Stage One and Stage Two Palliation.

Infants with a single ventricle can develop systemic ventricular dysfunction (SVD) after stage 1 operation, but available information is sparse. We reviewed our patients having Norwood, Sano, or hybrid procedures to better understand this problem. We conducted a retrospective, case-controlled cohort study of 267 patients having stage1 operation, examining outcomes between stages 1 and 2 (survival and subsequent cardiac surgeries), predictor variables, and histology of hearts explanted at transplantation. SVD developed in 32 (12%) patients and resolved in 13 (41%); mean age of onset was 3.0 ± 1.63 months; median = 2.79. SVD was not associated with cardiac anatomy, type of stage 1 procedure, weight, coronary abnormality, or atrioventricular valve regurgitation. The mean age of resolution = 12.1 ± 9.6 months; median = 6.3, and resolution may have been more likely with a systemic LV than RV (p = 0.067). Outcomes for the entire SVD group were less favorable than for those without, but patients with resolution of SVD had outcomes at least as good those without SVD. Myocardial histology (n = 4) suggested chronic ischemia. The risk of SVD after stage 1, while low, may be a fundamental feature of this patient population. SVD occurs with either a systemic RV or LV, although patients with a systemic LV may be more likely to have resolution than those with an RV. We identified no predictor variables, but histologic findings suggest chronic ischemia may be involved. Given the low incidence of SVD, multi-center studies will be required to better define predictors of onset and resolution.

Association of Extracorporeal Membrane Oxygenation Support Adequacy and Residual Lesions With Outcomes in Neonates Supported After Cardiac Surgery.

OBJECTIVES: There is a paucity of data regarding the impact of extracorporeal membrane oxygenation support, adequacy of surgical repair, and timing of intervention for residual structural lesions in neonates cannulated to extracorporeal membrane oxygenation after cardiac surgery. Our goal was to determine how these factors were associated with survival. DESIGN: Retrospective study. SETTING: Cardiovascular ICU. SUBJECTS: Neonates (≤ 28 d old) with congenital heart disease cannulated to extracorporeal membrane oxygenation after cardiac surgery during 2006-2013. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Eighty-four neonates were cannulated to venoarterial extracorporeal membrane oxygenation after cardiac surgery. Survival to discharge was 50%. There was no difference in survival based on surgical complexity and those with single or biventricular congenital heart disease. Prematurity (≤ 36 wk gestation; odds ratio, 2.33; p = 0.01), preextracorporeal membrane oxygenation pH less than or equal to 7.17 (odds ratio, 2.01; p = 0.04), need for inotrope support during extracorporeal membrane oxygenation (odds ratio, 3.99; p = 0.03), and extracorporeal membrane oxygenation duration greater than 168 hours (odds ratio, 2.04; p = 0.04) were all associated with increased mortality. Although preextracorporeal membrane oxygenation lactate was not significantly different between survivors and nonsurvivors, unresolved lactic acidosis greater than or equal to 72 hours after cannulation (odds ratio, 2.77; p = 0.002) was associated with increased mortality. Finally, many patients (n = 70; 83%) were noted to have residual lesions after cardiac surgery, and time to diagnosis or correction of residual lesions was significantly shorter in survivors (1 vs 2 d; p = 0.02). CONCLUSIONS: Our data suggest that clearance of lactate is an important therapeutic target for patients cannulated to extracorporeal membrane oxygenation. In addition, timely identification of residual lesions and expedient interventions on those lesions may improve survival.

Pulmonary arterial hypertension: what the large pulmonary arteries tell us.

The morphology of the large intrapulmonary arteries (PAs) in pulmonary hypertension (PH) has received limited attention. Dilation, pruning, abrupt tapering, and tortuosity of PAs occur, but whether different patients have distinct PA phenotypes is unknown. Pulmonary arteriograms from 41 pediatric patients with PH were blindly reviewed by four experts who assigned each angiogram one of three designations: straight (S), tortuous (T), or ambiguous (A). Hemodynamic variables and outcomes were compared to the phenotypes. Thirty patients were either T (19) or S (11); 11 were A. The phenotypes were not associated with age. Tortuous patients had higher PA pressure and resistance than the S group and less likely to react to inhaled nitric oxide than S patients (p < 0.05). Clinical outcomes were similar for the three groups. Thus, in PH patients two subtypes of PA morphology can often be discerned, a reflection of variability in PA tortuosity. These morphological subtypes have differing hemodynamic characteristics. The mechanism(s) underlying these differences is unknown, but neither hydrodynamic factors nor duration of PH are fully explanatory. Because PA morphology might reveal information regarding the biology of pathological remodeling, it might prove enlightening to assess the large PA phenotype in future studies of PH.

Pulmonary-to-Systemic Arterial Shunt to Treat Children With Severe Pulmonary Hypertension.

BACKGROUND: The placement of a pulmonary-to-systemic arterial shunt in children with severe pulmonary hypertension (PH) has been demonstrated, in relatively small studies, to be an effective palliation for their disease. OBJECTIVES: The aim of this study was to expand upon these earlier findings using an international registry for children with PH who have undergone a shunt procedure. METHODS: Retrospective data were obtained from 110 children with PH who underwent a shunt procedure collected from 13 institutions in Europe and the United States. RESULTS: Seventeen children died in-hospital postprocedure (15%). Of the 93 children successfully discharged home, 18 subsequently died or underwent lung transplantation (20%); the mean follow-up was 3.1 years (range: 25 days to 17 years). The overall 1- and 5-year freedom from death or transplant rates were 77% and 58%, respectively, and 92% and 68% for those discharged home, respectively. Children discharged home had significantly improved World Health Organization functional class (P < 0.001), 6-minute walk distances (P = 0.047) and lower brain natriuretic peptide levels (P < 0.001). Postprocedure, 59% of children were weaned completely from their prostacyclin infusion (P < 0.001). Preprocedural risk factors for dying in-hospital postprocedure included intensive care unit admission (hazard ratio [HR]: 3.2; P = 0.02), mechanical ventilation (HR: 8.3; P < 0.001) and extracorporeal membrane oxygenation (HR: 10.7; P < 0.001). CONCLUSIONS: A pulmonary-to-systemic arterial shunt can provide a child with severe PH significant clinical improvement that is both durable and potentially free from continuous prostacyclin infusion. Five-year survival is comparable to children undergoing lung transplantation for PH. Children with severely decompensated disease requiring aggressive intensive care are not good candidates for the shunt procedure.

Pathophysiology of acute pulmonary vasoconstriction.

Acute pulmonary vasoconstriction occurs in a variety of clinical settings relevant for the cardiac intensivist, postoperative pulmonary hypertension being perhaps the most common. Although we know that significant postoperative pulmonary vasoconstriction generally occurs in patients with a pathologically remodeled pulmonary circulation, we know little of its pathophysiology. The following review describes the biochemistry of smooth muscle contractile activation and examines the possible role that endothelin-1 may play in postoperative pulmonary hypertension.

Prostanoids in pediatric pulmonary hypertension: clinical response, time-to-effect, and dose-response.

For pediatric pulmonary arterial hypertension (PAH) patients treated with parenteral prostanoids, response predictors, and the dose-effect relationship are ill defined. We determined the following: (1) which pulmonary vascular hemodynamic variable, after initiating prostanoids, best correlates with a significant clinical response; (2) the time interval after treatment when if no pulmonary hemodynamic improvement has occurred, none is ever likely to; and (3) the relationship between the prostanoid dose and its hemodynamic effects. This is a retrospective cohort study of 31 pediatric patients with Group 1 PAH treated with parenteral prostanoids. We found the following: (1) A fall in mean pulmonary arterial pressure (mPAP) of ≥25% predicted freedom from adverse clinical events with 80.7% accuracy and was also associated with improved functional class. (2) Thirty-three percent of patients who avoided an adverse clinical event demonstrated a ≥25% reduction in mPAP after 1 year of treatment, and 65% by 2 years. (3) Lower mPAP was seldom seen with doses of epoprostenol >60 ng/kg/min (100 ng/kg/min for treprostinil). Cardiac index was positively correlated with the dose of epoprostenol but not treprostinil; cardiac index >4 l/min/m2 was seen at modest as well as high doses. We conclude that a ≥25% fall in mPAP on prostanoids indicates a positive clinical response which, if validated in other studies, may be useful for patient management or clinical trials. Some patients take more than 2 years for this change. Exceptionally high doses were generally not more effective than lower, although we could not determine whether lower doses would have been as effective.

Improving Safety of Intravenous Prostacyclin Administration to Pediatric Patients With Pulmonary Hypertension.

BACKGROUND: Pulmonary hypertension is a rare, life-threatening disease with limited therapeutic options and no definitive cure. Continuous intravenous prostacyclin therapy is indicated for treatment of severe disease. These medications have a narrow therapeutic index and a brief half-life; therefore, administration errors can be lethal. OBJECTIVE: To reduce medication errors through an inpatient program to improve, standardize, and disseminate continuous intravenous prostacyclin therapy practice guidelines. METHODS: Data were collected from the electronic safety reporting system of a single hospital to determine the number and types of continuous intravenous prostacyclin therapy errors that were reported over an 8-year period. A clinical database and hospital pharmacy records were used to determine the number of days on which hospitalized pediatric patients received the therapy. INTERVENTIONS: A nursing-directed quality improvement initiative to enhance the safety of continuous intravenous prostacyclin therapy for pediatric patients was begun in January 2009. Efforts to improve safety fell into 4 domains: policy, process, education, and hospital-wide safety initiatives. RESULTS: The number of therapy errors per 1000 patient days fell from 19.28 in 2009 to 5.95 in 2016. Chi-square analysis was used to compare the result for 2009 with that for each subsequent year, with P values of .66, .35, .16, .09, .03, .12, and .25 found for 2010 through 2016, respectively. CONCLUSIONS: The trend in reduction of continuous intravenous prostacyclin therapy errors suggests that proactive processes to standardize its administration, emphasizing both policy and education, reduce medication errors and increase patient safety.

The impact of right ventricular pressure and function on survival in patients with pulmonary vein stenosis.

Pulmonary vein stenosis (PVS) is associated with pulmonary hypertension (PH), but there is little information regarding the impact of PH on right ventricular (RV) systolic function and survival. We conducted a retrospective cohort study of our patients to explore this and other aspects of pulmonary hemodynamics with PVS. RV function was assessed using qualitative two-dimensional echocardiography. The ratio of systolic pulmonary artery (PA) and aortic pressures (PA:Ao) at cardiac catheterization reflected pulmonary hemodynamics. Reactivity testing employed inhaled nitric oxide + 100% fiO2, or 100% fiO2 only; "reactivity" was a ≥ 20% decrease in PA:Ao. There were 105 PVS patients, although not all had data at every time point. (1) The mean PA:Ao at first cardiac catheterization (n = 77) was 0.79 ± 0.36; at last catheterization (n = 54), PA:Ao = 0.69 ± 0.30; 90% had systolic PAP > one-half systemic. Survival was shorter with PA:Ao > 0.5. (2) Differences in survival relative to RV dysfunction on the first echocardiogram were not significant, although they were using the last echocardiogram. (3) The magnitude of RV dysfunction was positively correlated with PA:Ao. (4) Balloon dilation of PV acutely decreased PA:Ao (-0.13 ± 0.37, P = 0.03 [n = 40 patients]). 5. Of 20 patients tested, 13 were acutely reactive to vasodilators. PH is a major feature of PVS. Reduced RV function and PA:Ao appear to be predictors of survival. Given the importance of PH in this disease, clinical studies of PVS treatments should include measures of PAP and RV function as important variables of interest.

Pulmonary hypertension's variegated landscape: a snapshot.

The many types of pulmonary hypertension (PH) are so protean in their biological origin, histological expression, and natural history that it is difficult to create a summary picture of the disease, or to easily compare and contrast characteristics of one type of PH with another. For newcomers to the field, however, such a picture would facilitate a broad understanding of PH. In this paper, we suggest that four characteristics are fundamental to describing the nature of various types of PH, and that taken together they define a number of patterns of PH expression. These characteristics are histopathology, developmental origin, associated clinical conditions, and potential for resolution. The "snapshot" is a way to concisely display the ways that these signal characteristics intersect in select specific types of PH, and is an effort to summarize these patterns in a way that facilitates a "big picture" comprehension of this disease.

Duration of Mechanical Ventilation and Perioperative Care Quality After Neonatal Cardiac Operations.

BACKGROUND: This study was conducted to determine whether the duration of mechanical ventilation (DOMV) could be used to benchmark the overall quality of care after neonatal congenital heart operations. METHODS: Children aged younger than 30 days undergoing cardiac operations were reviewed. Technical adequacy was assessed using the Technical Performance Score (TPS), a previously validated tool for determining the adequacy of a palliative or corrective surgical procedure that uses echocardiography criteria and need for unplanned reintervention to determine technical adequacy. Preoperative risk factors and postoperative complications were determined using The Society of Thoracic Surgeons Congenital Heart Surgery Database definitions. Surgical complexity was assessed using The Society of Thoracic Surgeons-European Association of Cardio-Thoracic Surgery (STAT) Mortality Categories. We explored associations between preoperative risk factors, STAT category, TPS, and postoperative complications with DOMV. RESULTS: Of 601 patients studied, 49 were not included in the multivariable analysis due to a STAT nonclassifiable operation or unmeasured TPS, or both. Multiple risk factors were associated with longer DOMV, including weight (p = 0.005), The Society of Thoracic Surgeons Congenital Heart Surgery Database preoperative factors (p = 0.005), STAT mortality category (p < 0.001), TPS (p < 0.001), and The Society of Thoracic Surgeons Congenital Heart Surgery Database-defined complications (p < 0.001). Multivariable regression showed that preoperative factors increased DOMV by 1.23 days (p = 0.01), class 3 TPS by 2.16 days (p < 0.001), and postoperative complications by 2.03 days (p < 0.001), with adjusted R2 = 0.42. CONCLUSIONS: Neonates with major residual lesions and postoperative complications have prolonged DOMV. DOMV may reflect the quality of care after congenital heart operations.

Lung Pathology in Pediatric Pulmonary Vein Stenosis.

Pulmonary vein stenosis is a rare progressive narrowing of the extrapulmonary pulmonary veins, presenting predominantly in infancy and virtually always lethal. It typically arises following repair of congenital heart disease, particularly anomalous pulmonary venous return. Histologic characterization of pediatric pulmonary vein stenosis, not previously well described, may provide insight into the disease pathobiology. We retrieved archival lung specimens (biopsy, explant, or autopsy) from patients with pediatric pulmonary vein stenosis. Medical records were reviewed. Microscopic examination included hematoxylin and eosin (H&E)-stained slides, and for a subset of patients, elastic, trichrome, smooth-muscle actin, and D2-40. Groups with different clinical disease features were compared using Fisher's exact test. A total of 33 patients (median age, 7 months) had available tissue and 52% had congenital heart disease; 18% were premature. Within the lungs, interlobular septal veins showed thickened muscular coats (in 58%), proliferation/tortuosity (in 6%), and fibromyxoid intimal proliferation (in 3%). Associated arterial hypertensive changes were seen in 30 (91%). The one patient with intrapulmonary venous fibromyxoid intimal proliferation was the only patient with apparent primary familial disease. Lymphangiectasia and arterial medial hypertrophy were histologic features that correlated with clinical grouping. We conclude that in pediatric pulmonary vein stenosis, intrapulmonary pulmonary veins commonly show muscular thickening, best interpreted as venous hypertensive remodeling. Fibromyxoid intimal proliferation resembling that of the extrapulmonary pulmonary veins is uncommon. Awareness of intrapulmonary features in various clinical subtypes of pulmonary vein stenosis may be diagnostically and therapeutically informative considering that current catheter-based and surgical therapy is directed at the extrapulmonary component of pulmonary vein stenosis.

Efficacy and safety of milrinone in preventing low cardiac output syndrome in infants and children after corrective surgery for congenital heart disease.

BACKGROUND: Low cardiac output syndrome (LCOS), affecting up to 25% of neonates and young children after cardiac surgery, contributes to postoperative morbidity and mortality. This study evaluated the efficacy and safety of prophylactic milrinone in pediatric patients at high risk for developing LCOS. METHODS AND RESULTS: The study was a double-blind, placebo-controlled trial with 3 parallel groups (low dose, 25- microg/kg bolus over 60 minutes followed by a 0.25- microg/kg per min infusion for 35 hours; high dose, 75- microg/kg bolus followed by a 0.75- microg/kg per min infusion for 35 hours; or placebo). The composite end point of death or the development of LCOS was evaluated at 36 hours and up to 30 days after randomization. Among 238 treated patients, 25.9%, 17.5%, and 11.7% in the placebo, low-dose milrinone, and high-dose milrinone groups, respectively, developed LCOS in the first 36 hours after surgery. High-dose milrinone significantly reduced the risk the development of LCOS compared with placebo, with a relative risk reduction of 55% (P=0.023) in 238 treated patients and 64% (P=0.007) in 227 patients without major protocol violations. There were 2 deaths, both after infusion of study drug. The use of high-dose milrinone reduced the risk of the LCOS through the final visit by 48% (P=0.049). CONCLUSIONS: The use of high-dose milrinone after pediatric congenital heart surgery reduces the risk of LCOS.

Central venous line complications with chronic ambulatory infusion of prostacyclin analogues in pediatric patients with pulmonary arterial hypertension.

Chronic infusion of prostacyclin (PGI2) via a Broviac central venous line (CVL) is attended by risk of CVL-related complications, but we know of only one report regarding CVL-associated bloodstream infection (BSI) with PGI2 in children and none regarding other complications. We conducted a retrospective cohort study involving pediatric patients with pulmonary hypertension treated with chronic intravenous infusion of PGI2 at Boston Children's Hospital and determined the rate (per 1,000 line-days) of various CVL-related complications. We also determined how often complications necessitated line replacement and hospitalization, time to replacement of CVLs, and interpatient variability in the incidence of complications. From 1999 until 2014, 26 patients meeting follow-up criteria had PGI2 infusion, representing 43,855 line-days; mean follow-up was 56 months (range, 1.4-161 months). The CVL complication rates (per 1,000 line-days) were as follows: CVL-BSI, 0.25; superficial line infection, 0.48; impaired integrity, 0.59; occlusion, 0.09; and malposition, 0.32. The total complication rate was 1.73 cases per 1,000 line-days. All CVL-BSI and malposition cases were treated with CVL removal and replacement. Of CVLs with impaired integrity, 23 could be repaired and 3 required replacement. Six of 21 superficial CVL infections required replacement of the CVL. Three of 4 occluded CVLs were replaced. CVL complications occasioned 65 hospitalizations. There was marked interpatient variability in the rate of complications, much but not all of which appeared to be related to duration of CVL placement. We conclude that non-BSI complications are very significant and that efforts to teach and emphasize other aspects of line care are therefore very important.

Prophylactic intravenous use of milrinone after cardiac operation in pediatrics (PRIMACORP) study. Prophylactic Intravenous Use of Milrinone After Cardiac Operation in Pediatrics.

BACKGROUND: Many pediatric patients undergoing cardiac surgery involving cardiopulmonary bypass have a predictable fall in the cardiac index 6 to 18 hours after surgery, the so-called low cardiac output syndrome (LCOS). Because patients who have LCOS require more monitoring and support and have a prolonged stay in the intensive care unit, the syndrome is associated with a costly morbidity. Milrinone, a phosphodiesterase III inhibitor, improves cardiac muscle contractile force and vascular muscle relaxation through positive inotropic and vasodilatory effects. The purpose of the Prophylactic Intravenous Use of Milrinone After Cardiac Operation in Pediatrics (PRIMACORP) study is to evaluate the safety and efficacy of the prophylactic use of milrinone in pediatric patients at high risk for development of LCOS after undergoing cardiac surgery. METHODS: Patients in the multicenter, randomized, double-blind, placebo-controlled, parallel treatment study will be randomized to 1 of 3 treatment arms: (1) low-dose milrinone (25 microg/kg intravenous bolus over 60 minutes followed by a 0.25 microg/kg/min infusion for 35 hours), (2) high-dose milrinone (75 microg/kg intravenous bolus over 60 minutes followed by a 0.75 microg/kg/min infusion for 35 hours), or (3) placebo. RESULTS: The primary end point for efficacy evaluation will be based on a composite variable consisting of death or development of LCOS requiring additional mechanical or pharmacologic support, up to 36 hours after randomization. A 2-sided test with a 0.025 type I error will be used for the primary end point analysis. The PRIMACORP study will enroll a total of 240 patients. Six additional secondary end points will be analyzed. CONCLUSIONS: The PRIMACORP study will address several questions regarding the safety and efficacy of prophylactic milrinone use in pediatric patients at high risk for development of LCOS after cardiac surgery.

Use of extracorporeal life support as a bridge to pediatric cardiac transplantation.

BACKGROUND: Extracorporeal life support (ECLS) has been used for post-cardiotomy rescue, but its use as a bridge to heart transplantation (OHT) in patients with post-surgical or end-stage ventricular failure remains controversial. METHODS: Records were reviewed for patients receiving ECLS for ventricular failure from January 1991 to August 2001. Patients listed for OHT were analyzed separately. Listing for OHT requirements were improbable myocardial recovery, absence of contraindications (central nervous system damage, high pulmonary resistance, ongoing infection, etc.), and parental consent. Outcome variables included patient demographics, diagnosis, days from ECLS initiation to United Network for Organ Sharing (UNOS) listing (latency), list time, renal function, and survival to discharge. RESULTS: Of 145 patients with ventricular failure who received ECLS, 21 pediatric patients were UNOS listed. Of 124 non-listed patients, 57 (46%) survived to discharge. All but 3 survivors were separated from ECLS in

High systemic vascular resistance and sudden cardiovascular collapse in recovering Norwood patients.

BACKGROUND: Sudden death, remote from surgery, in patients with hypoplastic left heart syndrome (HLHS) after Norwood palliation is an important problem. The episodic nature of this syndrome has made its cause(s) difficult to ascertain. Observations made in hospitalized Norwood patients may afford insight into the pathophysiology of sudden death among these patients. METHODS: We conducted a retrospective chart review. RESULTS: Five patients with HLHS experiencing unremarkable recoveries from Norwood palliation, still hospitalized but extubated (only 1 in intensive care), had unexpected, acute decompensation 8 to 15 days postoperatively. All had acutely decreased peripheral perfusion; severe metabolic acidosis (mean HCO(3) = 9 mEq/L, range 6 to 11 mEq/L; mean arterial lactate = 16 mmol/L, range 10 to 20 mmol/L, normal less than 2 mmol/L); relatively high arterial pO(2), especially considering their low systemic perfusion (mean = 57 mm Hg, range 50 to 66 mm Hg on fraction of inspired oxygen (FiO(2)) less than 0.3 in 4 of 5 patients); and relatively high systolic blood pressure (mean systolic blood pressure = 91 mm Hg, range 78 to 116 mm Hg). During the preceding 24 hours, all had had systolic blood pressures of more than 85 mm Hg at multiple times. All were resuscitated with mechanical ventilation and administration of HCO(3) and intravenous inotropic agents or vasodilators (1 also required extracorporeal membrane oxygenation), with rapid resolution of their acidosis. After decompensating, all were treated with oral antihypertensive agents; 1 had an early hemi-Fontan. All survived to discharge. CONCLUSIONS: Increased systemic vascular resistance may be especially pernicious in Norwood patients-even remote from operation-as the condition increases myocardial work and O(2) consumption while diminishing systemic perfusion. Chronic and acutely increased systemic vascular resistance may account for some cases of sudden unexpected death in Norwood patients.

A retrospective review of three antibiotic prophylaxis regimens for pediatric cardiac surgical patients.

BACKGROUND: Optimal antimicrobial prophylaxis for the pediatric cardiac surgical patient is unknown. We have reviewed our experience with more than 4,000 pediatric cardiac surgical patients at the University of Michigan to evaluate antibiotic prophylaxis regimens. METHODS: Three antibiotic prophylaxis protocols were serially used during a 6-year period: Protocol 1 (n = 786): cefazolin was administered before operation and continued as long as thoracostomy tubes or central venous catheters were present; Protocol 2 (n = 1095): cefazolin was discontinued 48 hours postoperatively, regardless of the presence of tubes or catheters; Protocol 3 (n = 2039): cefazolin was continued as long as thoracostomy tubes were present, but not for central venous catheters. Patients with an open chest postoperatively received vancomycin and gentamicin until chest closure. This was identical during all three protocols. We retrospectively determined the rate of surgical site infections and unrelated bloodstream infections (the latter for both cardiac medical and surgical patients) for the three protocols. RESULTS: Surgical site infections per 100 operations for protocols 1, 2, and 3 was 2.04, 6.58, and 1.67, respectively (p < 0.05 for protocol 2 versus protocols 1 and 3). The mean age of patients with a surgical site infection ranged from 12 to 15.4 months. Patients with an open chest had a higher rate of surgical site infection (18.8% for protocol 2 and 9.3% for protocol 3). Bloodstream infections per 1,000 patient days for protocols 1, 2, and 3 were 2.18, 6.51, and 5.02, respectively (p < 0.05 protocol 1 versus protocols 2 and 3). CONCLUSIONS: These data suggest that pediatric cardiac surgical patients may benefit from prophylactic antibiotics as long as thoracostomy tubes are in place.