Fatal pulmonary embolism in hospitalised patients: a necropsy review

AIMS

To carry out a retrospective review of all postmortem reports during the period 1991 to 2000 at King's College Hospital, London, as an extension of a previous analysis performed for the period 1965 to 1990.

METHODS

The number of deaths resulting from necropsy confirmed fatal pulmonary embolism in hospitalised patients was determined, and a limited analysis of the clinical characteristics of those patients who died was performed.

RESULTS

During the 10 year period, 16 104 deaths occurred and 6833 (42.4%) necropsies were performed. The outcome measure, fatal pulmonary embolism, was recorded as cause of death in 265 cases (3.9% of all necropsies; 5.2% of adult cases). No deaths from pulmonary embolism occurred in patients under 18 years of age; 80.0% occurred in patients older than 60 years. Of the fatal emboli, 214 of 265 (80.8%) occurred in patients who had not undergone recent surgery. Of these patients, 110 (51.4%) had suffered an acute medical illness in the six weeks before death, most often an acute infectious episode (26 cases).

CONCLUSIONS

Thromboembolic events remain a relatively common cause of death in hospitalised patients and appear to occur more frequently in non-surgical than in surgical patients.

Comparison of a beta-lactam alone versus beta-lactam and an aminoglycoside for pulmonary exacerbation in cystic fibrosis

We determined whether a beta-lactam and an aminoglycoside have efficacy greater than a beta-lactam alone in the management of a pulmonary exacerbation in patients with cystic fibrosis.

STUDY DESIGN

Azlocillin and placebo or azlocillin and tobramycin were administered to 76 patients with a pulmonary exacerbation caused by Pseudomonas aeruginosa in a randomized double-blind, third-party monitored protocol. Improvement was assessed by standardized clinical evaluation, pulmonary function testing, sputum bacterial density, sputum DNA content, and time to the next pulmonary exacerbation requiring hospitalization.

RESULTS

No significant difference was seen between the 2 treatment groups in clinical evaluation, sputum DNA concentration, forced vital capacity, forced expiratory volume in second 1, or peak expiratory flow rate at the end of treatment (33 receiving azlocillin alone and 43 both antibiotics); adverse reactions were equivalent in each group. Sputum P. aeruginosa density decreased more with combination therapy (P =.034). On follow-up evaluation, an average of 26 days after the end of treatment, all outcome indicators had worsened in both groups. Time to readmission for a new pulmonary exacerbation was significantly longer in the group receiving azlocillin plus tobramycin (P <.001). Treatment-emergent tobramycin resistance occurred in both groups and was more frequent with combination therapy.

CONCLUSION

We conclude that the combination of a beta-lactam and an aminoglycoside produces a longer clinical remission than a beta-lactam alone and slightly better initial improvement.

Pulmonary function in children treated for rhabdomyosarcoma

Chemotherapy, radiation therapy, and surgical intervention have markedly improved the survival of patients treated for rhabdomyosarcoma. Unfortunately, the therapy may have deleterious effects on the lung. Pulmonary functions tests were obtained from 17 patients treated for rhabdomyosarcoma because of our concern regarding potential pulmonary dysfunction in this group of patients who had received bleomycin, which is known to be associated with lung injury. Mean age at the time of the diagnosis of rhabdomyosarcoma was 10.1 (+/- 7.2) years (range 0.01-23.5 years). The mean age at the time of pulmonary function testing was 17.0 (+/- 7.5) years (range 5.8-34.0 years). Study patients reportedly had no pulmonary symptoms. Approximately 87% of study patients had a restrictive ventilatory impairment on pulmonary function testing as measured by total lung capacity (TLC) values less than the lower limit of normal. Approximately 70% of study patients had carbon monoxide diffusing capacity (DLCO) values less than the lower limit of normal. There were no significant differences in pulmonary function parameters when male study patients were compared to female study patients. There was a statistically significant lower forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) ratio (P=0.03) and percent predicted forced expiratory flow at 25-75% of the FVC (FEF25-75; P=0.03) in the group of patients diagnosed with rhabdomyosarcoma over 8 years of age as compared to those individuals diagnosed under 8 years of age. In addition, there were no statistically significant differences in pulmonary function when the variables of sex and age at diagnosis (as outlined above) were studied in combination. In summary, we identified a high incidence of restrictive ventilatory abnormalities in a group of individuals (predominantly children) treated for rhabdomyosarcoma as well as a significantly lower FEV1/FVC ratio and percent predicted FEF25-75 in the group of patients diagnosed with the neoplasm over 8 years of age. Individuals caring for such patients are encouraged to obtain pre- and sequential posttreatment pulmonary function tests.

Replication-deficient adenovirus induces expression of interleukin-8 by airway epithelial cells in vitro

Preclinical studies with first-generation adenovirus (Ad) vectors administered in vivo to the respiratory tract have demonstrated a nonspecific host response consisting, in part, of parenchymal neutrophil accumulation followed by mononuclear cell and macrophage accumulation. We hypothesized that the mechanism for this host response might be the elaboration of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) from the airway epithelium following the exposure to Ad. To evaluate this hypothesis, we infected A549 cells (a human-derived lung epithelial cell line) in vitro with an adenovirus type 5 (Ad5)-based vector expressing a nuclear targeted beta-galactosidase enzyme (Av1LacZ4). We found that cellular transduction was efficient, resulting in gene delivery to 85.5% +/- 3.9% of the cell monolayer after 96 hr. Importantly, IL-8 mRNA transcript levels in Av1LacZ4-transduced cells were significantly higher than uninfected controls by 24 hr and remained elevated for 96 hr. IL-8 protein secretion from Av1LacZ4-transduced cells was increased for the same period. The Av1LacZ4-transduced A549 cells also showed a neutrophil chemoattractant activity higher than control cells, measurable at 24 hr, and persisting for 96 hr. The chemoattractant activity could be neutralized by a specific monoclonal antibody to IL-8. Whereas Av1LacZ4 transduction induced IL-8 gene expression, there was a lack of expression of MCP-1 by A549 cells. These observations demonstrate that the gene delivery to the airway epithelium using the Ad5-based expression vector results in IL-8 gene activation in these cells, which may contribute to the described inflammatory host response.

Lymphocyte subpopulations in children with abnormal lymphatic circulation

Peripheral blood lymphocyte subsets were enumerated in five children with abnormal lymphatic circulation (three with lymphangiectasia, one with chylothorax, and one child with chyloperitoneum). All patients were lymphopenic. The percentage and absolute number of blood T-lymphocytes (CD3) were low in two children and normal in the other children. The percentage and absolute number of helper/inducer lymphocytes (CD4) were markedly reduced in all patients. The percentage of suppressor/cytotoxic lymphocytes (CD8) was normal or elevated in all children, and the absolute number of CD8 cells was normal in three patients. The CD4/CD8 ratio was reversed in all patients. In the two patients tested, the proliferative response of peripheral blood mononuclear cells to mitogens was reduced. T-lymphocyte subsets were measured in the pleural or peritoneal fluid of three patients, and the CD4/CD8 ratio was normal or increased. In each child, the CD4/CD8 ratio in the lymphatic fluids was markedly higher than the CD4/CD8 ratio of the blood (4.0/0.45, 1.75/0.95, and 1.3/0.85). The reversed CD4/CD8 ratio in the blood in cases of chronic loss of chyle may be due to either selective transport of CD4 lymphocytes into the lymphatic fluids or a shorter half-life of CD8 compared to CD4 lymphocytes. This finding may in part explain the abnormal cellular immunity previously observed in patients with lymphangiectasia.

Aerosolized metaproterenol compared to subcutaneous epinephrine in the emergency treatment of acute childhood asthma

In a double-blind, randomized trial, we compared the effects of aerosolized metaproterenol to subcutaneous epinephrine in 35 episodes of acute asthma in children between 6 and 19 years of age. Patients were randomized to two parallel groups and then received both a placebo medication and an active medication to a maximum of three treatments. Repeated treatments were given to 15 patients on metaproterenol and 12 patients on epinephrine. Initial improvement in PEFR and FEV1 were statistically significant and comparable in both groups. Patients receiving a second metaproterenol treatment had more improvement in respiratory rate and clinical score compared with those in the epinephrine group. There were fewer treatment failures in the metaproterenol group. Followup at 24 to 48 hours showed significant treatment failure differences between the two groups (metaproterenol = 0, epinephrine = 5; p less than 0.05). Side effects were similar in both groups; in all instances they were mild, and their frequency did not increase in patients receiving repeated doses of medications. In conclusion, aerosolized metaproterenol was well tolerated in acute childhood asthma in repeated doses, and it appeared to be associated with prolonged bronchodilation and improved outcome.