Ventilación mecánica en el síndrome de dificultad respiratoria aguda/lesión pulmonar aguda

Acute respiratory distress syndrome (ARDS), which was first described by Ashbaugh in 1967, consists of acute hypoxemic respiratory failure (PaO2/FiO2< or =200) associated with bilateral infiltrates on the chest radiograph caused by noncardiac diffuse pulmonary edema. Although ARDS is of multiple etiology, pulmonary or extrapulmonary injury can produce systemic inflammatory response that perpetuates lung disturbances once the initial cause has been eliminated. Most patients with ARDS require mechanical ventilation. Currently, the old standard is conventional ventilation optimized to protect against ventilator-associated lung injury. Other mechanical ventilation strategies such as high-frequency oscillatory ventilation, which is also based on alveolar recruitment and adequate lung volume, can be useful alternatives. In this review, the level of evidence for other therapies, such as prone positioning, nitric oxide and prostacyclin inhalation, exogenous surfactant, and extracorporeal vital support techniques are also analyzed.

[Use of peripherally inserted multilumen catheters as an alternative to central venous access]

BACKGROUND

In the last decade alternatives to central venous lines in critically ill children have been developed. Multilumen catheters have classically been used through central venous access but there are no reports on their use as peripherally inserted central lines.

PATIENTS AND METHODS

We performed a retrospective study of patients admitted to the pediatric intensive care unit in the previous 3 years who underwent catheterization with peripherally inserted central venous lines. The catheters were four French, double-lumen and 30-cm long.

RESULTS

Twenty-two catheters were used in 22 children (mean age: 8.3 years; range 1.7-13.8). The catheters remained in place for a mean of 7.2 days. Ninety percent of the catheters were placed in antecubital veins. The catheters were used to administer antibiotics (59 %), other drugs (81 %), total parenteral nutrition (50 %) and blood (9 %). Central venous pressure monitoring was performed in eight patients. Complications were found in five patients (22 %): three cases of phlebitis, one catheter occlusion and one infection at the site of insertion. No significant differences were found in the complication rate between peripherally inserted catheters and 298 central venous catheters inserted in our unit in the same time period.

CONCLUSIONS

Peripherally inserted multilumen catheters may be an alternative in the management of critically-ill pediatric patients.

[Care of critically-ill children in Asturias (Spain): characteristics and effectiveness]

OBJECTIVE

To describe the work performed in the Pediatric Intensive Care Unit of the Hospital Central de Asturias (Spain) in its first 5 years and to assess the effectiveness of the care provided.

METHODS

A prospective study of the characteristics of critically-ill children admitted from 1996 to 2000 was performed. Effectiveness was defined as the ratio of observed to expected mortality, determined by pediatric risk of mortality (PRISM) score calculated 24 hours after admission.

RESULTS

The median age of critically-ill children was 38 months and the mean length of stay was 6.8 days. Forty percent of the patients were transferred from other hospitals in Asturias and Leon. The most frequent causes of admission were respiratory, neurological and infectious diseases, and trauma. Overall mortality was 4.3 %. Over the years the severity of the patients increased with a consequent rise in mean length of stay, use of central venous access and mechanical ventilation. Forty-two percent of deaths were expected. The effectiveness of care was high among high-risk patients, among those with respiratory and metabolic diseases and in the postoperative period but was low among patients with hematologic and gastrointestinal diseases. Effectiveness increased over time.

CONCLUSIONS

Studies analyzing pediatric intensive care units are useful for assessing and improving the effectiveness of care in these centers.

[Uric acid as a prognostic marker in critically ill patients]

BACKGROUND

Elevated uric acid concentrations reflect adenosine triphosphate degradation and suggest poor prognosis since they indicate a cellular bioenergetic crisis.

OBJECTIVE

To study uric acid concentrations as a prognostic marker of disease severity in critically ill children.

PATIENTS AND METHODS

Seventy-eight patients admitted to our pediatric intensive care unit with different diseases were prospectively studied. Thirty-five patients with meningococcal infection were retrospectively studied. Data on uric acid concentrations, diagnosis, length of stay, age, weight, the therapeutic intervention scoring system (TISS) and the pediatric risk of mortality score (PRISM) were collected. In patients with meningococcal infection severity was evaluated by studying evolution (death and the presence of sequelae or otherwise).

RESULTS

Uric acid concentrations on admission were significantly correlated with TISS on the first day (r 0.260; p 0.023) and with PRISM during the first 24 hours (r 0.277; p 0.015). In patients without craniocerebral trauma, correlations between uric acid concentrations and PRISM during the first 24 hours (r 0.524; p < 0.001) and correlations between uric acid concentrations with TISS on day 1 (r 0.483; p < 0.001) and day 2 (r 0.373; p 0.014) improved. In patients with craniocerebral trauma no significant correlations were found between uric acid and any of the other variables. In patients with meningococcal infection, uric acid concentrations on admission were closely related to evolution (uric acid concentrations were 13.20 8.2 mg/dl in patients who died, 8.01 1.77 mg/dl in those with sequelae and 4.72 1.84 mg/dl in in those without sequelae; p < 0.003).

CONCLUSIONS

Serum uric acid concentrations can be considered as a marker of severity in critically ill patients without craniocerebral trauma and especially in patients with meningococcal infection.

[Risk factors associated with nosocomial bacteremia in low birth weight neonates. Grady Memorial Hospital, Atlanta]

BACKGROUND

Nosocomial bloodstream infections occur frequently in Neonatal Intensive Care Units and are associated with recognized and unrecognized risk factors. Little has been published regarding risk factors for bloodstream infections in low birth weight neonates.

OBJECTIVE

To investigate risk factors for bloodstream infection in neonates < 1,500 g admitted at a Neonatal Intensive Care Unit.

METHODS

A prospective study was undertaken in low birth weight neonates (< 1,500g) during a 22 months period. Bivariant, and logistic regresion (stepwise procedure) analysis was used to determine the significance association of bloodstream infection and perinatal and nosocomial risk factors.

RESULTS

A total of 72 patiens with nosocomial bacteriemia and 147 non bacteriemic patients were studied. Independent risk factors associated with bloodstream infection were birth weight, persistence of umbilical catheter > 7 days and persistence of peripheral arterial catheter > 1 day.

CONCLUSIONS

The uses of umbilical catheter > 7 days, peripheral arterial catheter > 1 day and birth weight < 1,500 g were significant determinants of nosocomial bloodstream infection risk. Because of the importance of invasive procedures as a source of nosocomial bloodstream infections, the lines duration needs to be reviewed with the aim of reducing the incidence of blood stream infection.

[Blood pressure in childhood and adolescence. Its relationship with growth and maturation variables]

AIM

To analyze the relationship between blood pressure in childhood and adolescence and different variables including gender, age, weight, height, body mass index and sexual maturation.

METHODS

Cross-sectional study conducted in 1278 boys and girls aged 6 to 18 years old. Two blood pressure measurements were obtained. Mean value in the two measurements was obtained for each of the pressures: systolic (SBP), diastolic IV (DBPIV) and diastolic V (DBPV). Simple and multiple regression analysis were done to evaluate association between variables.

RESULTS

14 years 0.33; SBP boys > 14 years 0.34; DBPIV 0.25; DBPV 0.24) and height (SBP 6-13 years 0.33; SBP girls > 14 years 0.23; SBP boys > 14 years 0.29; DBPIV 0.25; DBPV 0.24) than for age (SBP 6-13 years 0.27; SBP girls > 14 years 0.17; SBP boys > 14 years 0.15; DBPIV 0.23; DBPV 0.22) for each of the blood pressures. Multiple regression analysis demonstrated a significant association between body mass index, height and SBP in the group of boys and girls aged 6-13 years old. No other significant associations were obtained.

CONCLUSIONS

Blood pressure values in childhood and adolescence show a positive association with growth and maturation variables. It's of capital importance to considerate not only age, but also height, weight and body mass index when evaluating the blood pressure value of a child.

[Hyperamylasemia after cardiac surgery in children]

OBJECTIVE

To analyze the incidence of hyperamylasemia after cardiac surgery in children, the pathogenic mechanisms and the relationship with morbidity and mortality.

PATIENTS AND METHODS

A prospective open study was made in the Intensive Care Unit of a tertiary care pediatric hospital. One hundred thirty-one patients (75 boys and 56 girls), between 7 days and 16 years of age, were studied after cardiac surgery between 1992 and 1994. We determined serum amylase on their admission, at 24 hours, between the 2nd and 5th days, and thereafter according to the clinical evolution. We considered a serum amylase higher than 250 UI/L as hyperamylasemia. We also determined liver enzyme levels (AST, ALT, Gamma-glutamyl transpeptidase, alkaline phosphatase, and direct and total bilirubin) and renal function (urea and creatinine). We studied the relationship between hyperamylasemia and the type of surgery, shock, renal insufficiency, hepatic alterations and mortality.

RESULTS

Fourteen patients (10%) showed hyperamylasemia. Mean serum amylase in these patients was 534 +/- 332.6 UI/L (range 252-1426 UI/L). Of the patients were cardiopulmonary bypass was performed, 11.4% presented hyperamylasemia, and 8.5% of the patients without a cardiopulmonary bypass surgery (non-significant difference). Of the children with hyperamylasemia, 42.8% suffered shock during the postoperative period after cardiac surgery and only 15.2% of the rest of the patients (p < 0.05). There were no differences in the incidence of renal insufficiency and liver alterations between children with hyperamylasemia and the rest of the patients. There was no significant difference between the mortality of children with hyperamylasemia (7.1%) and the rest of the children (4.7%; p > 0.05).

CONCLUSIONS

Hyperamylasemia is frequent after cardiac surgery in children. Hyperamylasemia is related to shock and the ischemia is probably the most pathogenic factor.

[Urinary concentration capacity in neonatal hydronephrosis]

In order to determine the renal concentration capacity in neonatal hydronephrosis, 10 micrograms of DDAVP were administered intranasally to 18 infants with hydronephrosis. Fluid intake was restricted to 50% of normal for 3 hours before and 6 hours after the administration of DDAVP. Maximal urine osmolality (mean +/- SD) was 348 +/- 180 mOsm/kg in 7 newborns younger than 21 days and 420 +/- mOsm/kg in 11 neonates between 22-50 days of age. Both osmolarities were inferior to the standard response to DDAVP reported in normal neonates. After 24 hours of clinical observation, we did not notice any secondary effects caused by this test.