Clinical rib fractures: are follow-up chest X-rays a waste of resources?

Rib fractures (RFs) are estimated to be present in 10 per cent of all traumatic injuries. However, up to 50 per cent of all fractures go undetected on the screening chest X-ray (CXR). The purpose of this study was to identify the incidence of clinical (CRFs) and objective rib fractures (ORFs) as well as to examine the utility of the routine follow-up CXR with regard to patient recovery and healthcare cost. We identified patients sustaining RF in addition to other traumatic injuries with an Injury Severity Score (ISS) < or = 15 and RF as the primary pathology. Five hundred fifty-two patients sustained blunt thoracic trauma with resultant RF. Two hundred nine patients had RFs and an ISS < or = 15. The average ISS was 8. Follow-up films illustrated that 93 per cent of CRFs had resolution of any pathology, 4 per cent had persistent X-ray findings, and 4 per cent were lost to follow-up. Ultimately 93 per cent of patients with CRF were able to resume daily activities without disability and 3 per cent incurred lifestyle changes at home or work, which was significantly better than those with ORFs (P < 0.05). Follow-up films produced no change in clinical management and cost approximately $2000/year. The prognosis for CRFs is excellent if treatment consists of appropriate pain management and pulmonary rehabilitation. We do not advocate routine follow-up CXRs in addition to physical examination for the evaluation of CRFs unless clinical deterioration is evident.

Exposure to toxic air contaminants in environmental tobacco smoke: an assessment for California based on personal monitoring data.

The contribution of environmental tobacco smoke (ETS) to the exposure of adult nonsmoking Californians was determined for selected toxic air contaminants (TACs). The assessment was based on published measurements of ETS emission factors and personal exposures to volatile organic compounds. The human exposure studies were conducted in three California areas--Los Angeles, Pittsburgh/Antioch, and Woodland--between 1984 and 1990. We derived unexposed and passive population exposure distributions by randomly sampling the monitoring results for individuals classified according to exposure status (active smoker, passively exposed or unexposed to ETS during monitoring). The differences between the unexposed and passive distributions were used to estimate the ETS-only contribution for exposure to benzene, styrene, o-xylene, and m,p-xylene. Emission factors were then employed to infer the ETS-caused exposure to thirteen other compounds. The estimated arithmetic mean increments of 24-hour exposure attributable to ETS for the nonsmoking Californian population (age > or = 7) exposed to ETS are as follows (results in units of microgram m-3 exposure concentration; results using two different emission factors presented as a range): acetaldehyde 11-15; acetonitrile 7.0; acrylonitrile 0.49; benzene 1.02; 1,3-butadiene 0.75-2.3; 2-butanone 1.4; o-cresol 0.17; m,p-cresol 0.41; ethyl acrylate < 0.015; ethylbenzene 0.49-0.64; formaldehyde 6.5-8.2; n-nitrosodimethylamine 0.0028; phenol 1.4; styrene 0.36; toluene 3.1-3.2; o-xylene 0.77; m,p-xylene 0.99. The 90% confidence limits on these estimates due to the limited sample size in the studies are roughly x/ divided by 6. For four widely studied compounds, ETS is estimated to contribute the following percentages to the total inhalation exposure of all nonsmoking Californians: o-xylene 5%; m,p-xylene 3%; benzene 5%; and styrene 8%.

HIV infection among rural trauma patients: a blind serosurvey and literature review.

Human immunodeficiency virus (HIV) seroprevalence rates among rural trauma patients range between 0.15 and 1.32 per cent. A random sample of trauma patients treated at our rural trauma center between September 1994 and November 1995 was enrolled into a blind HIV serosurvey. Five hundred sixty-six of 1315 trauma patients (43%) were tested. Two of the 566 patients (0.35%) were HIV positive. A review of aggregate data for HIV infection among rural trauma patients in the United States show that 28 of the 4639 patients (0.60%) are HIV positive. We conclude that there was a low HIV incidence among our trauma patients from September 1994 to November 1995, and the cost-effectiveness of HIV testing for rural trauma patients is questionable with incidences between 0.5 and 1.0 per cent.

A week in the country: a model respite program.

A family-oriented camping program for caregivers of children who are HIV infected is described. Major goals of the camping program consisted of: (1) providing respite care to mother and child, and, (2) training health care and mental health workers to provide special services, emphasizing the mental health needs of this population.

DPCM picture transmission over noisy channels with the aid of a Markov model.

The problem of DPCM picture transmission over noisy channels is considered. It is well known that DPCM systems are very sensitive to channel errors. The goal in this work is to build robustness against channel errors. Three methods are proposed in this paper and are obtained by modeling the encoded signal as a Markov sequence. First, an optimum method for decoding correlated sequences is derived, and it is shown to require Viterbi decoding. Then, a modified MAP method (MMAP) for Markov sequences is described. A maximal signal-to-noise (MSNR) receiver for DPCM systems is also developed that minimizes the distortion power due to channel errors. The appropriate cost matrix for this receiver is computed. These methods are applied to DPCM picture transmission over noisy channels and are compared with a another method. The SNR graphs, as well as subjective examination of the received pictures, demonstrate that the proposed procedures are quite effective and superior to that method. Among the proposed methods, the MSNR receiver was found to be more effective than the others for a given order of the Markov model. It is observed that the proposed methods are most beneficial for low detail pictures.