Bronchopulmonary dysplasia appropriateness as a surrogate marker for long-term pulmonary outcomes: A Systematic review

BACKGROUND

Bronchopulmonary dysplasia (BPD) is used to clinically describe the severity of lung disease and to serve as a common surrogate endpoint for long-term pulmonary morbidity in clinical trials, but its performance as a surrogate end-point warrants evaluation. Our objective was to assess real-world performance of BPD as a surrogate marker for long-term pulmonary outcomes.

METHODS

We performed a systematic review of large, multi-centered, blinded, randomized control trials to evaluate the use of BPD as a surrogate marker for long-term pulmonary outcomes. Long-term pulmonary outcomes occurred within two years and included measures of hospital utilization, respiratory illness, respiratory medication, and mortality. Direction and magnitude of effect were evaluated using number needed to treat analysis.

RESULTS

Five studies were included in our review. Studies varied in definition of BPD and in long-term outcomes measured. Only one study found a significant, consistent risk reduction in both BPD and any long-term pulmonary outcome. Two studies found significant reductions in long-term pulmonary outcomes with a non-significant reduction in BPD.

CONCLUSIONS

BPD is an imperfect surrogate marker for long-term pulmonary outcomes. It did not consistently predict the magnitude or direction of the effect of an intervention on longer-term pulmonary outcomes. Furthermore, there was significant variation in the definitions of BPD and in the long-term pulmonary outcomes used. There is a need for future work to identify more predictive surrogate markers and a need for better standardization of assessments of long-term pulmonary outcomes.

Apnea, bradycardia and desaturation in preterm infants before and after feeding

OBJECTIVE

A common clinical impression is that both gastroesophageal reflux (GER) and cardiorespiratory events increase after feeding in preterm infants. We aimed to measure objectively the effects of feeding on GER, apnea, bradycardia and desaturations.

STUDY DESIGN

We conducted a retrospective review of premature infants with a gestational age of 23 to 37 weeks at birth and a post-conceptional age of 34 to 48 weeks, who were referred for multichannel intraluminal impedance (MII), pH probe and 12-h apnea evaluation. Cardiorespiratory and GER event rates during pre- and post-feeding intervals were compared.

RESULT

Thirty-six infants met the inclusion criteria. More GER events occurred after a feed than before (P=0.012). After feeds, reflux was less acidic and higher in the esophagus (P<0.05). In contrast, the rates of apnea, bradycardia and desaturations were not altered by infant feeding. Apnea of >5 s occurred at a median frequency of 0 (range 0 to 3) events per hour before a feed and 0 (0 to 2) events per hour after a feed (P=0.61).

CONCLUSION

The frequency, height and pH of GER are significantly altered by feedings in preterm infants. However, the common clinical impression that apnea, bradycardia and desaturations are more prevalent after feeding is not supported.

The effect of inhaled nitric oxide on pulmonary function in preterm infants

OBJECTIVE

Bronchopulmonary dysplasia (BPD) in preterm infants is associated with impaired alveolar growth, inflammation and airway hyperreactivity. In animal models of BPD, inhaled nitric oxide (NO) improves alveolar growth and inhibits airway smooth muscle proliferation. This study was designed to assess the effect of inhaled NO on resistance and compliance in ventilated preterm infants with evolving BPD.

STUDY DESIGN

Expiratory resistance and compliance of the respiratory system were measured in 71 ventilated preterm infants, < or = 32 weeks gestation, randomized to NO (n=34) versus placebo (n=37) for > or = 24 days at 7 to 21 days of life.

RESULT

At baseline expiratory resistance (231+/-71 versus 215+/-76 cm H(2)O l(-1) s(-1)) and compliance (0.49+/-0.14 versus 0.53+/-0.13 ml cm H(2)O(-1) kg(-1)) were comparable between placebo and NO groups, respectively. There was no effect of NO on expiratory resistance or compliance at 1 h, 1 week or 2 weeks of study gas administration.

CONCLUSION

NO had no short- or medium-term effect on expiratory resistance or compliance in ventilated preterm infants.

Outcome of infants with bronchopulmonary dysplasia who receive extracorporeal membrane oxygenation therapy

BACKGROUND/PURPOSE

Extracorporeal membrane oxygenation (ECMO) is an accepted therapy for acute respiratory failure but more recently has been used in infants with bronchopulmonary dysplasia (BPD) and superimposed acute pulmonary insults. The purpose of this study was to review the outcomes of such infants.

METHODS

Charts of infants at The Children's Hospital of Philadelphia (CHOP) who had a diagnosis of BPD before ECMO were reviewed. In addition, to obtain survival data in a larger population, the Extracorporeal Life Support Organization (ELSO) Registry was searched for infants with BPD before ECMO.

RESULTS

Of 204 patients who received noncardiac ECMO at CHOP, 9 had BPD before ECMO. Of 7 survivors, 4 were still ventilator dependent at 9 to 39 months of corrected age. Developmentally, 4 had significant global delays, whereas 3 had significant language and motor delays with average to mildly delayed cognitive abilities. The ELSO Registry search showed 76 patients with BPD before ECMO, with a 78% survival.

CONCLUSIONS

The survival rate of infants with BPD who receive ECMO is comparable to, or better than, the survival rates in most other ECMO populations. However, there appears to be a high risk of severe pulmonary and neurodevelopmental sequelae.

Ulcerative colitis in a renal transplant patient with previous Goodpasture disease

A renal transplant was performed in a 6-year-old boy who developed end stage renal disease (ESRD) after presenting with antiglomerular basement membrane (anti-GBM) disease. At 10 years of age he developed ulcerative colitis while being immunosuppressed with cyclosporin, prednisone, and azothioprine. He had a pancolectomy, and at 14 years has no symptoms of ulcerative colitis or anti-GBM disease. HLA typing revealed that he was homozygous for HLA DR2. The co-occurrence of anti-GBM disease and ulcerative colitis has not previously been described. Although there is no known common etiology for these two autoimmune diseases, we propose that the patient's homozygosity at HLA DR2 may have predisposed him to both.

The murine Niemann-Pick type C lesion affects testosterone production

We have determined the effects of the Niemann-Pick type C (NPC) lesion, which impairs transport of cholesterol from lysosomes, on the androgenic status of male NPC mice. The mice have low serum testosterone levels resulting from decreased testosterone secretion. Testosterone secretion is reduced in NPC mouse testes incubated with 8-bromo-cAMP, 20 alpha-hydroxycholesterol, and pregnenolone compared to testosterone release by normal mouse testes under identical conditions. Ultrastructural examination of testes revealed a paucity of lipid droplets, extensive accumulation of inclusion bodies, and distorted endoplasmic reticulum in Leydig cells of adult NPC mice. The hypoandrogenemia caused systemic deficiencies in NPC mice. Seminal vesicles, a testosterone-responsive tissue, were underdeveloped in NPC male mice. The testosterone-responsive kidney beta-glucuronidase activity was also underexpressed. Seminal vesicle mass and beta-glucuronidase activity were increased by testosterone treatment of NPC mice. Many hepatic proteins, identified by microsequencing, were also deficient in NPC male mice. Levels of alpha 2-mu-globulin, glutathione S-transferase-pi, carbonic anhydrase-III, and selenium-binding protein increased in normal male mice during puberty, but did not increase in the NPC male mice. Based on the increases in protein expression during puberty, differential expression in males and females, and the reported involvement of androgens in regulating expression of some of these proteins, deficient expression of most of these proteins in male NPC mice appears to result from low testosterone levels. We conclude that a defect in testicular testosterone production in NPC male mice causes a pleiotropic deficiency in androgen-sensitive expression of proteins in various organs.

Nutritional and environmental studies on an ocean-going oil tanker. 2. Heat acclimatization and nutrient balances

Collins, K. J., Eddy, T. P., Hibbs, A., Stock, A. L., and Wheeler, E. F. (1971).Brit. J. industr. Med.,28, 246-258. Nutritional and environmental studies on an ocean-going oil tanker. 2. Heat acclimatization and nutrient balances. On the oil tanker S.S. Esso Newcastle, metabolic balances were investigated in three medical students and three working members of the crew during three-day experiments conducted when the ship was located in Biscay, the South Atlantic, and the Persian Gulf. Information was sought on the possible changes in nutrient requirements and the significance of the losses of nutrients in sweat when the subjects became acclimatized to heat. Physiological parameters of acclimatization were measured on each subject by controlled hyperthermia using a heated test-bed. Details are also given of the procedures devised for measuring the daily intake and loss of nutrients in metabolic balance studies on working subjects. The intakes of water, sodium (including salt supplements), potassium, nitrogen, and iron provided by the ship's diet were found to be adequate, or more than adequate, during the outward voyage to the Persian Gulf. In two crew subjects who worked in the engine room, there was a trend to more positive salt and water balance with sweat losses of 3 to 4 litres per day in the Persian Gulf, but not in the three students who, though artificially acclimatized, were seldom exposed to hot working conditions. Sweat concentrations of sodium, potassium, and nitrogen were related to the rate of 24-hour sweat loss but were not altered by heat acclimatization. In the environmental and dietary conditions on board, the effect of daily sweat losses of potassium, nitrogen, and iron on the respective balances was found to be insignificant. The urinary output of 17-OH corticosteroids increased slightly in mid-voyage in the students but was not raised in either students or crew in the Persian Gulf. There was evidence of temporary increases in plasma cortisol accompanied by negative nitrogen and potassium balances when unacclimatized crew members were exposed to heat stress at the start of the voyage.