Conventional and conventional plus modified ultrafiltration during cardiac surgery in high-risk congenital heart disease

BACKGROUND

This prospective nonrandomized study is the critical assessment of conventional ultrafiltration (CUF) and modified ultrafiltration (MUF) techniques and their efficiency in congenital heart disease surgeries. Use of cardiopulmonary bypass (CPB) in children is associated with body water retention as a consequence of prime volume and systemic inflammatory reaction. The CUF during CPB has reduced body water excess and the MUF after CPB, removes inflammatory mediators, improves hemodynamic performance, and decreases transfusion requirements.

METHODS

Forty-one patients, aged 9 to 36 months, submitted to surgical correction for cardiac defects, using CPB, were divided into 2 similar groups: CUF (21 patients) operated between 1996-1997 were ultrafiltered during CPB, and CUF+MUF, (20 patients) operated between 1997-1998 and ultrafiltered during and after CPB. Postoperative duration of ventilator support, pediatric intensive care unit stay (PICU), hospital stay of the groups with and without preoperative pulmonary hypertension (PH), as well as transfusion requirement, hematocrit and platelet counts were compared.

RESULTS

There were no technical complications and a significant ultrafiltrate in the CUF+MUF group was observed as compared to the CUF group. No significant differences were observed between the CUF and CUF+MUF groups regarding ventilatory support, PICU stay and hospital stay. Requirements for red cell transfusion, Ht and platelet counts were not statistically different.

CONCLUSIONS

CUF and CUF+MUF were safe and efficient methods for patient stabilization independent of diagnosis and complexity of surgery. Future clinical evaluation should address a larger population of patients to research the different variables.

Comparison of two different severity scores (Paediatric Risk of Mortality [PRISM] and the Glasgow Meningococcal Sepsis Prognostic Score [GMSPS]) in meningococcal disease: preliminary analysis

Two different illness severity scores, Pediatric Risk of Mortality (PRISM) and the Glasgow Meningococcal Sepsis Prognostic Score (GMSPS), were evaluated and compared in meningococcal disease in two paediatric intensive care units. Forty-nine children with a median age of 36 months who had meningococcal sepsis confirmed by laboratory data were evaluated. Overall mortality was 18%. The median GMSPS was 3 in survivors and 8 in non-survivors. A GMSPS > or = 8 was significantly associated with death (p = 0.0001) with a mortality predictivity and specificity of 70% and 92.5%, respectively. The median PRISM score in survivors was 5.5 and 23 in non-survivors. A PRISM score of > or = 11 was significantly related to death (p < 0.0001). The Kendal correlation co-efficient between GMSPS and PRISM showed tau = 0.6859 (p = 0.0000). It is concluded that GMSPS and PRISM are useful methods for identifying and classifying children into low and high risk categories. GMSPS > or = 8 or a PRISM score > or = 11 are significantly predictive of mortality.

[Dosage of atrial natriuretic peptide in pediatric patients submitted to mechanical ventilation]

OBJECTIVE

The aims of this article are to verify if there is any alteration in the secretion of natriuretic atrial factor (NAF) in children submitted to mechanical pulmonary ventilation and if these possible alterations would lead to modification in the urinary volume and in the urinary sodium excretion.

METHODOLOGY

A prospective study in a tertiary pediatric intensive care unit, nine children submitted to mechanical pulmonary ventilation for recuperation from anesthetics, except one who suffered a not surgical cranioencephalic trauma. The period of the study was from September 1995 to March 1996. Patients with renal pathology, pulmonary pathology, in use of diuretics until 24 hours before the collection of laboratory dosages, hemodynamic instability in need of vasoactive and inothropic agents, and patients with alterations of sodium blood levels were excluded from this work. In order to have an adequate alveolar recruitment at least 3 hours were taken. After this period a blood sample was collected for dosage of natriuretic atrial factor, arterial gas analysis, glucose analysis, creatinine and electrolytes dosage. Urine was collected in a 6 hours interval during the patient's period under mechanical pulmonary ventilation in order to verify the urinary volume and urinary sodium excretion. Fifteen to thirty minutes after extubation, blood an urine were collected for the same dosages done before. Urine was collected in a 6 hour period. A statistical comparison was done by the non parametric test of Wilcoxon signed rank, with a significance level of 0,05.

RESULTS

The natriuretic atrial factor showed tendency to increase when mechanical pulmonary ventilation was taken away (p=0,0547). The urinary volume and natriuresis were not altered by mechanical pulmonary ventilation.

[Inhalation of nitric oxide - dependence: case report]

OBJECTIVE: Describe the hemodynamic response with rebound of pulmonary hypertension after withdrawal of inhaled nitric oxide (NO) in a pediatric patient with acute respiratory distress syndrome (ARDS). METHODS: Case report of a child with ARDS and pulmonary hypertension evaluated through ecocardiografic with dopller, receiving inhaled NO for a period of 21 days. RESULTS: There was a decrease of the pulmonary artery pressure (PAP) from 52 mmHg to 44 mmHg after the initial titulation of NO inhalation dose. After the withdrawal of inhaled NO an elevation of PAP was observed (55 mmHg). It was necessary to reinstall the inhaled NO to obtain a more appropriate value (34 mmHg). A new attempt of interruption of the inhaled NO after prolonged inhalation (20 days) resulted in a new clinic worsening and increase of PAP, with the indication to reinstall the inhaled NO. In the 24th day of permanence in the intensive care unit the patient died due to multiple organ dysfunction. CONCLUSIONS: The possibility of pulmonary hypertension rebound after withdrawal of inhaled NO is a complication that may have important clinical implications for patients who need a prolonged treatment with NO. This case report emphasizes these implications.

[Complications of arterial catheterization in children]

The radial artery catheterization with the purpose of children's monitoring has been more and more used in Pediatric Intensive Care Units, and many times, is use is indispensable, like in cardiac surgery post-operative cases. However, there are only a few articles on the subject among us.

PURPOSE

To analyse the complications of radial artery catheterization in the post-operative of cardiac surgery in children.

METHODS

We studied the complications of this procedure in 120 children in cardiac surgery post-operative range from 1 month to 2 years. The children were catheterized by percutaneous technique (n = 67) and by cutdown technique (n = 53). The following complications were analysed in relation to the placement time of the catheter and the used technique: local infection, hemorrhagic complication, ischemia, catheter occlusion and accidental catheter displacement.

RESULTS

Infection, ischemia and hemorrhage were more frequent and statistically significant in patients submitted to cutdown technique, while the catheter occlusion and accidental displacement were similar in both groups. The placement time of the catheter was an important variable in our study. All of the other infection cases occurred after 72 hours of the catheterization and the frequency of hemorrhage and ischemia was higher in the first 72 hours.

CONCLUSION

The main complications of this proceeding are related to the technic utilized, time of utilization of the catheter and to the characteristics of the patients.

[Sedation and analgesia at the emergency room]

OBJECTIVES: To present research data about the adverse effects of pain and agitation in the emergency room with the best therapeutic options.METHODS: Review of the literature, covering some of the most important studies about analgesia and sedation in the emergency room, and pharmacokinetics and pharmacodynamics of the most important drugs.RESULTS: The metabolic responses, scales of evaluation of pain and anxiety and the different clinical situations in the emergency room are presented, inluding also the main drugs to be used.CONCLUSIONS: In the situations of stress in the emergency room we should not underestimate the clinical situations that cause pain and anxiety.

[Auto-PEEP effects on respiratory mechanics and blood gases in mechanically ventilated patients]

OBJECTIVE: The purpose of this study was to examine the auto-PEEP incidence and magnitude and the relationship between its reductions and changes in respiratory mechanics and gas exchanges in mechanically ventilated patients addmited in an Intensive Care Unit.METHODS: A prospective study was conducted in seventeen infants undergoing mechanical ventilation due to respiratory or neuromuscular diseases. We have measured blood gases, mean airway pressure, tidal volume, compliance, resistance and time constants of the respiratory system and monitored pressure, flow and volume waveforms and pressure-volume and flow-volume loops.RESULTS: Thirteen patients or 76% developed auto-PEEP and the reduction of its magnitude (from 5.4 -/+ 3.2 to 4.1 -/+ 2.6 cmH2O, p<0.01) showed association to mean airway pressure decrease (from 10.2 -/+ 3.1 to 9.3 -/+ 2.3 cmH2O, p<0.01), tidal volume (from 45.3 -/+ 19.1 to 51.3 -/+ 22.9 ml, p<0.01) and corrected compliance increase (1.02 -/+ 1.20 to 1.13 -/+ 1.41 ml/cmH2O/kg, p=0.05). Expiratory resistance remained unchanged (from 15.0 -/+ 8.6 to 15.7 -/+ 9.4 cmH2O/l/sec/kg, p=0.06). Arterial blood gases showed pH increase (from 7.37 -/+ 0.12 to 7.42 -/+ 0.05, p<0.05) and PCO2 and PO2 decrease (from 40.1 -/+ 11.1 mmHg to 33.1 -/+ 7.4 mmHg, p<0.01 and 65.0 -/+ 13.9 to 58.0 -/+ 12.6 mmHg, p<0.01 respectively).CONCLUSIONS: Auto-PEEP reduction was associated with pulmonary mechanics and blood gases improvement. Knowledge of auto-PEEP presence and magnitude allowed to respiratory system compliance and time constants correction, providing accurate index of the pulmonary mechanics.

[Mechanical ventilation in children]

OBJECTIVE: To make a brief review about mechanical ventilation in Pediatrics.METHODS: Review of the classification of types of mechanical ventilation, characteristics of pression and flow waves and indications for its installation. In a sequential way we discuss the various modes of ventilation (control ventilation, assisted-control ventilation, assisted ventilation, intermittent mandatory ventilation, synchronized intermittent mandatory ventilation, pressure-support ventilation) showing some advantages and disadvantages of using these modes. RESULTS: General rules for mechanical ventilation are presented, considering some specific pathologies in Pediatrics (acute respiratory distress syndrome, bronchopleural fistulae, cranial trauma, cardiac failure, neuromuscular pathology, acute asthma and in patients with acute descompensation of a cronic respiratory failure). CONCLUSIONS: Some limitations of mechanical ventilation and the possible advances in a short period are presented.

[Hemostatic changes in children treated with heart surgery with cardiopulmonary bypass]

PURPOSE

We evaluated hemostasic changes in children undergoing open heart surgery with cardiopulmonary bypass (CPB).

METHODS

We studied 17 children before, during surgery, in the immediate, first and between the 4th and 7th postoperative days, measuring hematocrit, prothrombin time, activated partial thromboplastin time, fibrinogen, platelet count, factor V and euglobulin lysis time. Children were divided in those with and without excessive bleeding in the postoperative period.

RESULTS

We observed significant prolongation of prothrombin time and activated partial thromboplastin time, reduction of fibrinogen and factor V, and shortening of euglobulin lysis time. Six (35%) children bled excessively. Platelet count reduction was greater in the intra operative period in these cases and the duration of CPB was longer in this group.

CONCLUSION

Changes in hemostasis during open heart surgery are due to coagulation cascade disorders as well as fibrinolysis. The incidence of excessive bleeding is higher in the pediatric group. Prolonged CPB time and greater reduction in platelet count differentiated both groups.