Abstract
Background:
Inflammatory reaction can produce several complications after cardiac surgery. Many attempts have been made to reduce these complications; perioperative corticosteroid therapy is one of the simplest methods.
Objectives:
We conducted a randomized study to evaluate the efficacy of single dose methylprednisolone, prescribed after surgery, for reducing the complications. Repair of Tetralogy of Fallot was chosen as a homogenous large group for the study.
Patients and Methods:
One hundred children who underwent total repair of Tetralogy of Fallot were enrolled in this study. After the surgery, all patients were transferred to pediatric ICU and were randomized (in a double-blind fashion) in 2 groups (A and B); a single dose of methylprednisolone (30 mg/kg of body weight) was injected to participants of group “A” just at the time of ICU entrance. Group “B” received no drug. Then, clinical outcomes and laboratory data were compared between the two groups.
Results:
The only significant differences were lower incidence of bacteremia and higher incidence of hyperglycemia in the group who were used methylprednisolone.
Conclusions:
Using a single postsurgical dose of methylprednisolone does not significantly alter the clinical outcome after repairing Tetralogy of Fallot.
Keywords: Heart Disease, Congenital, Tetralogy of Fallot, Corticosteroid, Cardiac Surgery
1. Background
Systemic inflammation is a natural response to cardiopulmonary bypass (CBP)(1-3). Inflammatory mediators can cause severe complications such as low cardiac output syndrome (LCOS) and profound vasodilatory hypotension (4). Minor complications like postpericardiotomy syndrome are also known as inflammatory reactions(5). Inflammatory response to CBP is more severe in younger patients. Several attempts have been made to regulate this inflammatory response. Using modified ultrafiltration (MUF) and administration of perioperative corticosteroids are the commonly accepted methods (6). Inflammatory process continues after the surgery and it lasts as tracheal tube left in place as well as the tubes for thoracic and mediastinal drainage.
2. Objectives
Based on the existing literature,we attempted to evaluate the benefit of an additional single dose of corticosteroid at the entrance to Intensive Care Unit (ICU) for children underwent cardiac surgery for repairing Tetralogy of Fallot (TOF). TOF was chosen as a relatively common congenital heart disease. Therefore, a large sample of a homogenous entity with similar surgical method could facilitate the evaluation for the drug efficacy.
3. Patients and Methods
3.1. Participants
One hundred children (aged 0-15 years) who underwent total repair of Fallot’s tetralogy in Rajaie Cardiovascular Medical and Research Center (The main tertiary center of pediatric cardiology and cardiac surgery) were enrolled. The study was approved by the Ethics Committee of the center. A consent form was taken fromthe parents. In all cases, the general anesthesia was induced with fentanyl (10-15 mg/kg), sodium thiopental (3-5 mg/kg) and pancuroniumbromide (0.15 mg/kg). The anesthesia was continued with sevofluraneinhalation and bullous doses of fentanyl. A single dose of methylprednisolone (30 mg/kg) had been used before cardiopulmonary bypass (CPB). After the surgery, all patients were transferred to pediatric ICU.
3.2. Intervention
After ICU entrance, the patients were randomized into 2 groups (A and B); a single dose of methylprednisolone (30 mg/kg of body weight) was injected for group “A” just at the time of ICU entrance. Group “B” received no drug. For all patients, dobutamine (0.01 mg/kg/min) plus milrinone (0.1 mg/kg/min) was started just after the surgery. All patients received cefazolin (100 mg/kg/day) in 3 divided doses for 3 days. Inotropes and antibiotics were adjusted based on the individual needs of the patients.
3.3. Outcome
All patients were monitored in the same ICU and managed by one pediatric cardiologist. For all participants, heart rate, arterial pressure, and blood oxygen saturation were continuously monitored. Complete blood count (CBC), including red blood cell (RBC), white blood cell (WBC) and platelet (PLT) count, erythrocyte sedimentation rate, C reactive protein, blood glucose, sodium, potassium, calcium, magnesium, prothrombin time (PT), international normalized ratio (INR), and partial thromboplastin time (PTT) were checked for all participant at the onset of ICU admission and then daily until discharge. A blood sample was also sent for bacteriology and culture at the onset of ICU admission and the day after. All patients received mechanical ventilation support with synchronized intermittent mandatory ventilation. Then, any abnormal laboratory data were compared between the two groups.
3.4. Randomization
We used balance block randomization. The Random Allocation Software version 1.0 (Isfahan University of Medical Sciences, Isfahan, Iran) was used for randomization.
3.5. Concealment
Because of the special milky appearance of methylprednisolone, a placebo could not be prepared. Three nurses were in charge of the drug prescription, they recorded their data in confidential forms marked by the patients’ codes. Medical management was done by a pediatric cardiologist who was blind to the study results. All laboratory data were reported by a web-based computerized system and the laboratory personnel did not know about the study.
3.6. Statistical Analysis
Data were reported as mean ± standard deviation (SD) for interval and count (%) for categorical variables. We used the chi-square test for categorical variables and Student t test for numerical variables and Mann-Whitney U test for Analysis of 2-Between-Group Data with a Quantitative Response Variables . Multivariate logistic regression models were used to investigate adjusted associations between variables. P value < 0.05 is considered as statistically significant result. SPSS 15 for Windows (SPSS Inc. Chicago, Illinois) was used for statistical analysis.
4. Results
One hundred patients (46 girls) with mean age of 39 ± 22.3 months were enrolled in the study. Number of the patients, gender distribution, age range and the body weights of the two groups were not significantly different (Table 1). The number of patients who had undergone palliative procedure, namely modified Blalock-Taussig shunt was also not significantly different between the two groups. Seventy patients experienced at least one clinical or paraclinical unwanted situation. The total number of these adverse events was not statistically different between the two groups (Table 2). When the adverse events were compared one by one, bacteremia was significantly more common in drug users and hyperglycemia was significantly more common in the control group. All 6 cases of bacteremiawere seen in corticosteroid non-user group. In 4 cases the bacterium was Staphylococcus aureus and in 2 Pseudomonas aeruginosa. Some other differences were seen, but they were not statistically significant.Low cardiac output syndrome was mostly seen in corticosteroid non-users. Low cardiac output syndrome was defined when decrease in cardiac output manifested with hypotension, respiratory insufficiency, oliguria, enteral feeding intolerance and increased serum lactate. Tachyarrhythmias were slightly more frequent in corticosteroid non-user group. The most frequent arrhythmia was junctional ectopic tachycardia, which was observed in 14 cases. Frequent ventricular ectopiesand ventricular tachycardia were seen in two patients; in one of them junctional ectopic tachycardia was also seen. One case experienced atrial tachycardia. All arrhythmias were medically controlled. Outcomes of the two groups are compared in Figure 1. Multivariate analysis with adjusted confounders showed no significant differences in adverse outcomes between the patients received corticosteroid and the control group (Table 3).
Table 1. Comparison of Demographics BetweenCorticosteroid Users and the Control Group a.
| Group A, Corticosteroid Users | Group B, Corticosteroid Non-Users | P Value | |
|---|---|---|---|
| Demographics | |||
| Gender | 1.000 | ||
| Female | 23 | 23 | |
| Male | 27 | 27 | |
| Age, mon | 39.8 ± 24.7 | 38.2 ± 19.8 | 0.917 |
| Body weight, Kg | 12.9 ± 4.3 | 12.7 ± 3.7 | 0.992 |
| Previous shunt operation | 16 (32) | 17 (34) | 0.832 |
| Modified Ultra-Filtration | 10 (20) | 9 (18) | 0.799 |
| PUMP time for surgery | 106.2 ± 27.8 | 111.12 ± 31.8 | 0.505 |
aData were described as Mean ± SD or No. (%).
Table 2. Comparison of Outcome Between Corticosteroid Users and the Control Group a.
| Group A, Corticosteroid Users | Group B, Corticosteroid Non-Users | P Value | |
|---|---|---|---|
| Clinical situations | |||
| Fever, rectal temperature > 37.6 for infants and > 38 for children | 9 (18) | 15 (30) | 0.160 |
| Abnormal bleeding, > 10 mL/kg | 13 (26) | 19 (38) | 0.198 |
| Oliguria, < 0.5 mL/kg/h | 3 (6) | 1 (2) | 0.307 |
| Renal failure, creatinine clearance < 10 mL/min | 2 (4) | 0 | 0.153 |
| Sepsis, systemic inflammatory response resulting from a suspected or proven infection | 2 (4) | 4 (8) | 0.400 |
| Duration of mechanical ventilation, h | 18.2 ± 11.04 | 25.5 ± 31.3 | 0.688 |
| Low cardiac output syndrome | 1 (2) | 3 (6) | 0.307 |
| ICU stay, d | 3.02 ± 1.9 | 3.22 ± 2.1 | 0.565 |
| Arrhythmia | |||
| Tachyarrhythmia | 6 (12) | 10 (20) | 0.275 |
| Complete heart block | 1 (2) | 1 (2) | 1.000 |
| Abnormal Hematology | |||
| Anemia, hemoglobin level of less than the 5th percentile for age | 1 (2) | 0 | 0.315 |
| Thrombocytopenia, PLT count < 150000/mm3 | 3 (6) | 1 (2) | 0.307 |
| Coagulopathy, (PT > 12 s, INR > 1, or PTT > 35 s | 8 (16) | 6 (12) | 0.564 |
| Leukocytosis, WBC count > 2 SD for age | 0 | 1 (2) | 0.315 |
| Polynucleosis, Neutrophil count > 50% of total WBC count | 0 | 1 (2) | 0.315 |
| Bacteremia, positive blood culture for a specific microorganism | 0 | 6 (12) | 0.012 |
| Electrolyte imbalances | |||
| Hyperglycemia, serum Glucose > 150 mg/dL | 31 (62) | 21 (42) | 0.045 |
| Hypocalcaemia, total serum calcium < 8.5 mg/dL | 6 (12) | 4 (8) | 0.505 |
| Hypokalemia, serum potassium < 3.5 meq/L | 1 (2) | 3 (6) | 0.366 |
| Hypomagnesaemia, serum Magnesium < 1.5 mg/dL | 0 | 1 (2) | 0.315 |
| Adverse outcome b | 37 (74) | 33 (66) | 0.383 |
aData were described as Mean ± SD or No. (%).
bThe number of patients who experienced at least one of the abnormal clinical or paraclinical findings.
Figure 1. Comparison of the Unwanted Findings Between the Corticosteroid Users and the Control Group.
Table 3. Multivariate Analysis for Adjusting Confounders and Assessment of the Corticosteroid Effect on Adverse Outcomes.
| Variable | Coefficient | P Value | Odds Ratio | C.I. 95.0% for Odds Ratio | |
|---|---|---|---|---|---|
| Group | 0.384 | 0.402 | 1.468 | 0.590 | 3.601 |
| Age | 0.044 | 0.134 | 1.045 | 0.987 | 1.107 |
| Gender | 0.311 | 0.511 | 1.365 | 0.539 | 3.457 |
| Body weight | -0.147 | 0.305 | 0.864 | 0.653 | 1.143 |
| PUMP time | -0.004 | 0.652 | 0.996 | 0.981 | 1.012 |
| Modified Ultra-Filtration | 0.322 | 0.600 | 1.379 | 0.414 | 4.597 |
| Previous shunt operation | 0.738 | 0.214 | 2.092 | 0.654 | 6.694 |
5. Discussion
Although corticosteroids are widely used in perioperative period for children undergoing cardiac surgeries (7), there was serious controversies about their clinical benefit. However, effectiveness of corticosteroids has been shown in inotrope refractory neonates with low cardiac output syndrome after cardiac surgery (8). Clarizia et al. reported that intraoperativesteroid administration can improve postoperative outcome in children undergoing high risk cardiac surgeries(9). Crow et al. evaluated dexamethasone levels in infants who had received the drug before cardiopulmonary bypass (10). Methylprednisolone significantly lowers the plasma concentrations of interleukins 6 and 8 and increases the level of interleukin 10, all in favor of decreasing inflammatory response. However, a significant clinical benefit was not observed by many authors (11). While intraoperative corticosteroid is used in many centers for pediatric cardiac surgeries, Graham et al. showed that an additional preoperative dose does not enhance the clinical outcome and even may exacerbate perioperative renal dysfunction (4). In a large multicenter study, Pasquali et al. could not find a significant benefit for perioperative corticosteroid in pediatric congenital heart surgeries (12). Mastropietro et al. reported that greater cumulative doses of corticosteroid in the perioperative period were associated with higher rate of postoperative infections (13). Verweij et al. and Green et al. showed that the effect of hydrocortisone in post-op low cardiac output doesnot directly depend on the adrenal sufficiency and the plasma cortisol levels (14, 15).
Our study focused on the clinical outcome. We also evaluated the common paraclinical disturbances that can potentially alter the patient’s condition. We found few benefits for using the additional corticosteroid dose at ICU entrance. One of the significant different outcomes between two groups was hyperglycemia. It was more common in patients who received additional dose of the corticosteroid. Our multivariate analysis showed no significant difference in outcome between hyperglycemic and non-hyperglycemic patients. However, Alaei et al. found higher mortality and morbidity in children with severe hyperglycemia after cardiac surgery (16). Bacteremia without clinical findings of sepsis syndrome was less common in our patients who received additional doses of the corticosteroid. The multivariate analysis again showed no significant difference in clinical outcome; however, it is likely for a child with bacteremia to exhibit aseptic complications, especially in immunocompromised conditions. It was shown that different anesthetic regimens my affect the outcome in TOF operation (17), althoughthe regimen was similar in our cases. It is not guaranteed thatstudy with other kinds of anesthetic drugs would yield the similar results.
One serious limitation for our study was the small number of patients who were used modified ultrafiltration; a method that can seriously affect the outcome. The other limitation was the lack of long-term follow-up. In pediatric patients undergoing surgical repair for Fallot’s tetralogy, a postoperative additional dose of methylprednisolone does not significantly improve the clinical outcome.
Acknowledgments
We would like to appreciate Gholaamreza Omrani, Nader Givetaj, Ramin Baghaei, and Maziar Gholampour (cardiac surgeons) for their contribution to the study. The authors thank Dr Hooman Bakhshandeh for his generous assistance in statistical analysis. All pediatric ICU nurses were appreciated for their collaboration too.
Footnotes
Authors’ Contributions:Mohammad Dalili developed study concept and design and drafted the manuscript. Ahmad Vesal contributed to the data acquisition. Avisa Tabib supervised the study and did critical revision of the manuscript for important intellectual content. Leila Khani-Tafti contributed to data analysis and interpretation. Shirin Hosseini contributed to statistical analysis. Ziae Totonchi had critical revision of the manuscript for important intellectual content.
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