Computed tomography in the management of blunt thoracic trauma.

Computed tomographic (CT) scanning has proved to be valuable in evaluating the head and abdomen of victims of blunt trauma; CT scans of the thorax often are obtained on patients with blunt torso trauma, but their value for this purpose is unclear. We conducted a prospective study to evaluate the role of chest CT scanning in thoracic trauma. Hemodynamically stable patients at least 18 years old with an estimated Abbreviated Injury Scale--Thorax score of 2 or greater underwent a contrast-enhanced CT scan of the chest, usually in conjunction with CT scans of the head, abdomen, or both. Thirteen patients were dead on arrival, 14 required emergency surgical procedures, and 13 were too unstable to undergo chest CT scan. Thirty-three patients were not included because they refused to participate or the protocol was not followed. Forty-six men (69%) and 21 women with a mean age of 42.7 years completed the study. Sixty-one were injured in motor vehicle crashes, four were injured in falls, and one each was injured by assault and by crushing forces. Injury Severity Scores ranged from 4 to 45, with a mean of 20.5. Four patients died (6%), three from head injury and one from multiple organ dysfunction. Chest roentgenography (CXR) was superior to CT scanning in identifying rib fractures, but CT scanning was more sensitive than CXR for pneumothorax, fluid collections, and infiltrates (p < 0.001); CT scanning also was more specific for aortic injury. Despite this quantitative superiority, the abnormalities missed by CXR but identified by CT scanning infrequently led to a change in management.(ABSTRACT TRUNCATED AT 250 WORDS)

Vasopressin and plasma volume response to submaximal and maximal exercise in man.

Plasma arginine vasopressin (PAVP), plasma volume loss (PVL) and blood lactic acid (LA) responses to submaximal exercise were examined in 16 normal, healthy individuals. Subjects volunteered to participate in three experiments conducted at the same time of day (9 am) with 7 days intervening between tests. Venous blood was removed before and immediately after 15 min exercise at 40% and 70% VO2max, and before and after 100% VO2max which lasted for 14.3 +/- 1.4 mins (mean +/- SD). The resting mean values of PAVP were similar on the three testing occasions (p greater than 0.05). PAVP rose significantly (p less than 0.05) to all exercise treatments and exhibited an exercise-intensity related response. Similarly, PVL (calculated from changes in haematocrit) and LA responses to exercise were increased with increasing workload. No direct relationship was found between PAVP changes and PVL or LA responses to submaximal exercise (p greater than 0.05). These results suggest that (a) PAVP levels increase to exercise with a response related to exercise intensity; (b) the stimuli generated directly or indirectly to exercise may be one of many factors causing an increase in PAVP.

Effect of continuous intra-aortic balloon inflation in canine open chest cardiopulmonary resuscitation.

In a canine model of open chest CPR, the effect of continuous intra-aortic balloon (IAB) inflation on cerebral and myocardial perfusion was investigated utilizing hemodynamic and radioactive microsphere techniques of assessing regional blood flow. Compared to deflation, IAB inflation augmented the following variables, expressed as percentage of prearrest control: aortic systolic (50% to 71%) and aortic diastolic (40% to 58%) pressures during 30-sec inflations; and epicardial blood flow (BF) (44% to 57%), mesocardial BF (40% to 56%), endocardial BF (36% to 50%), carotid BF (32% to 51%), and cerebral BF (67% to 88%) during inflations of greater than 150 sec. IAB inflation had no effect on right atrial pressure; thus, estimated cerebral and myocardial perfusion gradients were augmented. IAB inflation may prove to be a beneficial adjunct to open chest CPR.

Relations between erythrocyte lithium efflux, blood pressure and family histories of hypertension and cardiovascular disease: studies in a factory workforce and hypertension clinic.

Sodium-dependent lithium efflux was measured in erythrocytes from 399 factory workers and 125 patients attending a hypertension clinic. Thirty-two factory workers had unsuspected essential hypertension (diastolic blood pressure phase V greater than 90 mmHg). These subjects had the same average erythrocyte lithium efflux as those with normal blood pressure, whereas lithium efflux was increased on average in the clinic hypertensives. Lithium efflux was greater in those subjects from both groups who had a family history of high blood pressure. Our clinic hypertensives did not have raised lithium efflux when they were matched for family history; the increased lithium efflux in the group as a whole (and in analysis of published reports) was explained by an excess of subjects with a family history of hypertension. Furthermore, when a family history of hypertension was present, lithium efflux was increased on average only in those whose relatives also had a cardiovascular event associated with their high blood pressure. These results, in conjunction with detailed analysis of the distributions of lithium efflux within the groups, suggest that, though not linked to blood pressure itself, an increase in lithium efflux is an inherited marker for those at risk from the cardiovascular complications associated with high blood pressure.

Abnormal indices of nutrition in the elderly: a study of different clinical groups.

Anthropometric and biochemical indices of nutrition were measured in 450 elderly women in six groups spanning a wide range of physical dependency. Data from the group of active subjects living at home was used to derive reference ranges for elderly women. Although the index values of this group did not differ greatly from those seen in young subjects, there were large differences between this and some of the other elderly groups where the frequency of low values was as high as 50% for some parameters. Food intakes were measured in four of the six groups and relationships were found between energy, protein and vitamin C intake and body weight, plasma protein levels and vitamin C concentration, respectively. Our findings suggest that, among elderly women, low levels of nutrient intake make a significant contribution to poor anthropometric and biochemical nutritional status. Improvements in diet should be reflected in the indices measured and might, in turn, have beneficial effects on health.

Ventilatory response to increased dead spaces in the first week of life.

We have developed a method for quantitatively assessing respiratory control in a group of 10 full-term healthy babies, mean age at test 5 days, by measuring their ventilatory response to added external dead spaces. The dead spaces were equal to 0.5, 1, 2, and 3 anatomic dead spaces (2.2 ml/kg body weight), respectively. Tidal volumes were measured by a nasal mask and a 200-I rigid container. End-tidal CO2 was monitored via a tube in the nostril by a mass spectrometer. Baseline measurements were made during a 10-minute period, after which similar recordings were obtained with each of the dead space tubes. The system was calibrated against a 20-ml syringe. The mean baseline ventilation was 602 ml/minute. On the addition of 0.5, 1, 2, and 3 dead spaces, minute ventilations were increased by 37.5, 74.7, 150.7, and 273.6%, respectively. These increases were due to rises in tidal volume rather than respiratory rate. End-tidal CO2 rose by 1.8 and 4 mmHg on the addition of 2 and 3 dead spaces. When the results were compared with expected minute ventilations--based on the baseline recordings and corrected for the added dead spaces and for changes in anatomic dead space ventilation due to alterations in respiratory rate--the results were within 10% of expected values.

Nutritional state of elderly women on admission to mental hospital.

Since nutritional deficiencies might worsen the severity of symptoms and prolong the length of illness in non-nutritional disorders, particularly in the elderly, we examined the nutritional status of 216 elderly women newly admitted to a mental hospital. Compared to healthy elderly women, they had lower values for plasma prealbumin, vitamin C, and B vitamins. This was particularly common in senile dementia, and appeared to be the result of inadequate intake of protein or vitamins. Regular hospital diet for one month corrected the very low levels of prealbumin, but supplements were essential to remove deficiency of the water-soluble vitamins. Although vitamin supplements did not influence the length of stay in hospital, we did not exclude the possibility that nutritional deficiencies have a significant effect on the severity of mental illness.

The cause and correction of low blood vitamin C concentrations in the elderly.

Chronically sick elderly women had low intakes and low blood concentrations of vitamin C. Small dietary supplements of vitamin C increased the concentration of vitamin C in their plasma and leucocytes to those found in both the active elderly and the young. These findings confirm that low concentrations of vitamin C in the institutionalized and chronically sick elderly are primarily due to poor intake and can be easily corrected by dietary changes. The case for increasing the intake of vitamin C in these patients is discussed.

A comparison of alternative arrangements for an out-of-hours chemical pathology service.

Until 1979, the out-of-hours chemical pathology service was the conventional on-call service in which the medical laboratory scientific officers (MLSOs) carried out analyses at the direct request of clinical staff. In 1980, during an industrial dispute, junior ward doctors were trained to use three simple instruments which are maintained by the chemical pathology department. In January, 1981, when the dispute was settled, the doctors continued to use these instruments. Analyses they could not make were done by the MLSO on call, but only after the requests were monitored by a chemical pathologist or biochemist. The result was an 80% reduction in the number of calls. When the monitoring was withdrawn in 1983, there was some increase in the number of MLSO calls, but this was still 35% less than that with the conventional system despite a 4-fold increase in the total number of analyses done out of hours between 1979 and 1984. Surveys in 1984 and in early 1985 revealed that most doctors preferred using the instruments to asking an MLSO to make the analysis.

Mass and composition of the fat-free tissues of patients with weight-loss.

An estimate of the mass of fat-free tissue in the body can be calculated from body weight and skinfold thickness; this estimate is called the 'fat-free mass'. Total body potassium and nitrogen are alternative estimates. Factor analysis of data for healthy subjects has defined relationships between the true values of these three quantities and estimated the random component of the variance of each, i.e. the component independent of variations in the mass of fat-free tissue. The results indicated that all three were reliable measures of the mass of fat-free tissue. However, it is not known whether these findings are valid for patients who have lost weight. We have measured the same three quantities in 104 wasted patients with heart disease or disorders of the gastrointestinal tract. The patients' mean values were significantly less than corresponding values for healthy volunteers. The patients had a mean ratio of total body nitrogen to fat-free mass similar to that of healthy subjects, but lower mean ratios of potassium to fat-free mass and nitrogen. These findings suggest that the potassium content of the patients' fat-free tissues was abnormally low. Factor analysis of the patients' data gave relationships between the true values of the three quantities similar to those for healthy subjects; however, total body potassium was 100-300 mmol lower in patients than in healthy subjects with the same fat-free mass or total body nitrogen.(ABSTRACT TRUNCATED AT 250 WORDS)

A study of two diuretic/potassium combinations in heart failure.

The effect of potassium supplements was studied in 28 patients taking long term frusemide (40-80 mg daily). Plasma potassium fell when supplements were stopped, and rose towards prior values on the potassium/frusemide combination, Diumide K. In a crossover study in 14 of these patients comparing equivalent doses of frusemide, Diumide K (frusemide 40 mg, potassium 8 mmol), bumetanide, and Burinex K (bumetanide 0.5 mg, potassium 7.7 mmol) plasma potassium was lower on frusemide than on bumetanide. On Diumide K and Burinex K plasma potassium rose significantly but did not reach the levels on prior therapy. Small doses of potassium in combined formulations seem to be effective in countering the mild hypokalaemia caused by loop diuretics.

Tubular damage in patients with hypokalaemia.

Severe hypokalaemia is occasionally associated with gross changes in renal tubular function. We have looked for lesser degrees of renal tubular damage in unselected patients with hypokalemia by measuring the urine excretion of total protein, albumin, the low molecular mass protein beta 2-microglobulin (B2M) and two enzymes, N-acetyl-glucosaminidase (NAG) and alanine aminopeptidase (AAP). The frequency of abnormal values for these tests separately (compared with matched patients without hypokalaemia) was 39-56%. Many patients had an abnormal value for more than one of the tests, but this was at least partly due to chance association rather than to an underlying common mechanism for the several abnormalities. The frequency of abnormal values was greatest in the patients with the lowest plasma potassium concentrations, but not all of these patients had abnormal values for even one of the tests. Repeated measurements during treatment with potassium supplements showed that the tubular damage resolved in some patients but more slowly than the hypokalemia. These results demonstrate that renal tubular damage is common amongst patients with hypokalaemia and is probably a consequence of the hypokalaemia in most of them. The measurements allow detection of patients whose tissues (at least the kidney) are adversely affected by the hypokalaemia, but the clinical usefulness of this information is yet to be established.