Treatment of acute pulmonary failure with extracorporeal support: 100% survival in a pediatric population

Viral Infection in the Development and Progression of Pediatric Acute Respiratory Distress Syndrome

Viral infections are an important cause of pediatric acute respiratory distress syndrome (ARDS). Numerous viruses, including respiratory syncytial virus (RSV) and influenza A (H1N1) virus, have been implicated in the progression of pneumonia to ARDS; yet the incidence of progression is unknown. Despite acute and chronic morbidity associated with respiratory viral infections, particularly in "at risk" populations, treatment options are limited. Thus, with few exceptions, care is symptomatic. In addition, mortality rates for viral-related ARDS have yet to be determined. This review outlines what is known about ARDS secondary to viral infections including the epidemiology, the pathophysiology, and diagnosis. In addition, emerging treatment options to prevent infection, and to decrease disease burden will be outlined. We focused on RSV and influenza A (H1N1) viral-induced ARDS, as these are the most common viruses leading to pediatric ARDS, and have specific prophylactic and definitive treatment options.

Pathogenesis and management of respiratory insufficiency following pulmonary resection

The underlying principle of the surgical treatment of non-small-cell lung cancer (NSCLC) is complete removal of the local/regional disease within the thorax. Pulmonary resection should be as conservative as possible without compromising the adequacy of tumor removal. A multitude of factors influence the incidence and severity of complications following pulmonary resection including the pre-operative physical and psychological status of the patient, the pathologic process requiring resection, the physiologic impact of the procedure, and the addition of pre-operative or postoperative adjuvant therapy. The insidious onset of interstitial changes on chest X-ray (CXR) 1 to 2 days after pulmonary resection forewarns of respiratory distress; however, the pathophysiology of adult respiratory distress syndrome (ARDS) with progression to respiratory failure requiring mechanical ventilation and advanced critical care often unfolds. Management of patients with severe respiratory failure remains primarily supportive. "Good critical care" is the mainstay of therapy: this includes gentle mechanical ventilation to avoid ventilator-induced barotrauma and over-extension of remaining functional alveoli, diuresis, infection identification and management, and nutritional support. New therapeutic strategies that may impact on outcomes in the adult population include pressure-limited ventilation (permissive hypercapnia), inverse ratio ventilation, high-frequency jet ventilation, high-frequency oscillatory ventilation, intratracheal pulmonary ventilation, and prone position ventilation. In addition, alternative therapies such as partial liquid ventilation, inhaled nitric oxide, and extracorporeal techniques including extracorporeal membrane oxygenation (ECMO), extracorporeal carbon dioxide removal (ECCO(2)R), intravascular oxygenation (IVOX), and arteriovenous carbon dioxide removal (AVCO(2)R), provide additional modalities. A component of some or all of these strategies is finding a role in clinical practice.

Clinical experience with the MEDOS HIA-VAD system in infants and children: a preliminary report

BACKGROUND

The need of pediatric cardiac assist is growing because of the complexity of the congenital conditions operated on and the increasing number of pediatric transplantations. We evaluated the newly developed pediatric MEDOS HIA-VAD ventricular assist device.

METHODS

The pneumatic paracorporeal ventricular assist device has three left ventricular sizes (10-, 25-, and 60-mL maximum stroke volume) and three right ventricular sizes (9, 22.5, and 54 mL) and can be operated effectively with up to 180 cycles/min. We used this device in 6 consecutive pediatric patients. Intention of treatment was to bridge to transplantation in 3 patients and to aid in recovery from a cardiac operation in 3. Age ranged from 5 days to 8 years.

RESULTS

Two children died during assist, 2 were weaned from the system and discharged home, and 2 had successful transplantation. During assist, laboratory variables indicative of impaired renal, hepatic, or pulmonary function normalized or showed a trend toward normalization. Both deaths were related to infection.

CONCLUSIONS

With the new MEDOS HIA-VAD ventricular assist device system, pediatric mechanical cardiac assist can be performed successfully. It requires timely implantation, careful monitoring, and adequate size-matched devices.

Extracorporeal life support for the treatment of viral pneumonia: collective experience from the ELSO registry. Extracorporeal Life Support Organization

Viral pneumonia is the most common indication for pediatric extracorporeal life support (ECLS). Despite this fact, no previous studies have directly stratified patient outcome according to viral etiology.

METHODS

Using the Extracorporeal Life Support Organization (ELSO) registry database, the authors reviewed the national experience of patients undergoing ECLS with culture or serologically demonstrated viral pneumonia and compared outcome parameters according to viral etiology.

RESULTS

Patients differed with respect to age and weight according to the viral type. Patients with respiratory syncytial virus (RSV, median age 3 months), herpes simplex virus (HSV, 0.13 months), cytomegalovirus (CMV, 2.5 months), and adenovirus (0.6 months) were younger than those with other viruses (5.5 months). The patient groups did not significantly differ with respect to pre-ECLS Pao2 mean airway pressure (MAP), oxygenation index (OI), mode, or duration of ECLS. The overall survival of patients with viral pneumonia was 57%, although patients with RSV or CMV were found to have a 67% survival. Patients infected with HSV and adenovirus had a significantly lower survival rate (31% and 25%, respectively) when compared with those with RSV. In addition RSV pneumonia was associated with fewer cardiovascular complications than several of the other viral types. When comparison was made between survivors and nonsurvivors, a higher last pre-ECLS MAP and increased incidence of elevated creatinine and renal failure requiring dialysis were noted among nonsurvivors.

CONCLUSION

ECLS remains an important modality in the treatment of neonatal and pediatric patients with respiratory failure secondary to viral pneumonia. The survival rate of these patients varies according to the type of viral infection.

How often is extracorporeal membrane oxygenation needed in cases of congenital diaphragmatic hernia?

Some newborns with congenital diaphragmatic hernia (CDH) and severe pulmonary hypertension cannot be saved by conventional treatment and may obtain some benefit from extracorporeal membrane oxygenation (ECMO) as a bridging measure until adequate hematosis is possible. Early prediction of the insufficiency of "optimal" assistance is still unclear; we reviewed our recent experience with CDH patients in an attempt to evaluate the real need for ECMO in our institution. Between 1987 and 1994, 47 newborns with CDH manifested in the first 24 h were treated with maximal ventilatory assistance (including high-frequency ventilation in 12 cases) and vasoactive drugs prior to surgical repair. In order to summarize the ventilatory and blood-gas parameters, we determined oxygenation index (OI) and ventilatory index (VI) and compared the results in survivors and nonsurvivors. Overall survival was 60% (2 cases of Fryns' syndrome were excluded from analysis). OI was 10.3±5.7 (mean ± SD) for survivors and 46.2 ± 37.8 for nonsurvivors (P < 0.01). VI was 460.9±303 and 1,532±500.6, respectively (P <0.01). Bayesian analysis and receiver operating characteristic curves enabled us to select a threshold value of OI of 20 as the best means of predicting survival in our current conditions (sensitivity: 0.7, specificity: 0.83). The generally accepted figure of 40 had a sensitivity of 1 but a specificity of only 0.44. For VI, the best threshold value was 1,100 (sensitivity: 0.93, specificity: 0.94), whereas the generally used figure of 1,000 had 0.89 and 1, respectively. According to our results, with our current management conditions, approximately 50% of our CDH patients might have obtained some benefit from ECMO.

Open lung biopsy in pediatric patients on extracorporeal membrane oxygenation

Open lung biopsy has proven beneficial in the treatment of life-threatening pulmonary diseases. Its safety and efficacy in infants and children placed on extracorporeal membrane oxygenation (ECMO) for severe respiratory failure is not known. The authors reviewed eight cases (4 neonates, 3 infants, 1 child) who underwent open lung biopsy while on ECMO. The primary diagnoses were pneumonia (4), lymphoma (1), primary pulmonary hypertension (1), and complex congenital heart disease (2). The patients underwent biopsy after they had been on ECMO an average of 9.6 days (range, 1 to 14 days). Biopsy results confirmed the clinical diagnosis in five patients, two of whom had irreversible alveolar destruction resulting in ECMO withdrawal. Three patients had pathological diagnoses, which resulted in major therapy revisions (1 fungal infection and 2 noninfectious lesions that required steroid treatment). The overall average duration of ECMO treatment was 16.3 days (range, 10 to 24 days). Three patients were weaned successfully from ECMO, but only one infant survived to discharge. One nonlethal bleeding complication occurred after biopsy. Open lung biopsy is well tolerated during ECMO. It accurately determines pulmonary pathology and provides valuable prognostic information. Earlier biopsy for patients whose diagnoses are uncertain or who are not responding to ECMO may improve the mortality rate for this high-risk group.

Accumulation of 5-ethyl-2'-deoxyuridine and its 5,6-dihydro prodrugs in murine lung and its potential clinical application

The accumulation of 5-ethyl-2'-deoxyuridine (EDU), (--)-trans-(5S,6S)-5-bromo-5-ethyl-6-methoxy-5,6- dihydro-2'-deoxyuridine [(5S,6S)-BMEDU], (+)-trans-(5R,6R) -5-bromo-ethyl-6-methoxy-5,6-dihydro- 2'-deoxyuridine [(5R,6R)-BMEDU], (+)-trans-(5R,6R)-5-bromo- 5-ethyl-6-ethoxy-5,6-dihydro-2'-deoxy- uridine (BEEDU), (+)-trans-(5R,6R)-5-bromo-5-ethyl-6-ethoxy -5,6-dihydro-5'-O-valeryl-2'deoxyuridine (VBEEDU) [formula: see text] and (+)-trans-(5R,6R)-5-bromo-5-ethyl-6-ethoxy-5, 6-dihydro-3'-5'-di-O-valeryl-2'-deoxyuridine [formula: see text] (DVBEEDU) in lung and other tissues was investigated in male Balb-C mice following intravenous injection of the corresponding 4-(14)C-labelled compounds. EDU showed a rapid distribution into liver and lung immediately after injection, and the overall levels of radioactivity in blood, liver and lung were similar. The distribution of radioactivity in lung after injection of [4-(14)C](5S,6S)-BMEDU and [4-(14)C]5R,6R)-BMEDU were substantially different from one another and also from that of[4(-14)C]EDU. The radioactivity level present in lung samples after injection of both (4-(14C](5S,6S)-BMEDU and [4-(14)C](5R,6R)-BMEDU was substantially higher than that in blood samples. Radioactivity levels present in lung samples taken at 18 min after injection of [4-(14)C]BEEDU were significantly higher (P < 0.05) than those for liver and blood samples. Although the radioactivity present in lung samples after injection of [4-(14)C]BEEDU did not provide a higher radioactivity level in lung samples than did [4-(14)C]BEEDU.(ABSTRACT TRUNCATED AT 250 WORDS)

Improved arterial oxygenation in children with the adult respiratory distress syndrome: the prone position

Seven ventilated children with the adult respiratory distress syndrome (ARDS) were studied. While supine and haemodynamically stable, baseline arterial blood-gas analyses and haemodynamic measurements, including cardiac output, were performed. Each child was then turned prone and 30 min later a repeat set of measurements were made. Following this, the children were returned to the supine position and 30 min later a final set of measurements were performed. Ventilation and inotropic support remained unchanged during these positional changes. No significant effect on heart rate, mean systemic arterial blood pressure and cardiac output occurred following these positional changes (p > 0.05; Friedman's ANOVA). Arterial oxygen saturation significantly improved, however, when nursed in the prone position (p < 0.02). Similarly, oxygen delivery significantly increased (p < 0.02). The prone position improves arterial oxygenation and oxygen delivery in children with ARDS. By adopting the prone position, in ventilated children with ARDS, we surmise that realistic gas exchange targets may be reachable with lower levels of inspired oxygen and/or peak airway pressures.