Time to CT and Surgery for HPB Trauma in Scotland Prior to the Introduction of Major Trauma Centres.

AIMS: To assess the time taken to CT and emergency surgery for trauma patients with an injury to liver, spleen or pancreas prior to the introduction of major trauma centres (MTCs) in Scotland. METHODS: A search was performed of the Scottish Trauma Audit Group database for any patient with relevant injuries over a 2-year period. Primary outcome measures were time to CT and emergency surgery. Patient demographics were also recorded. RESULTS: A total of 211 patients were identified of whom 23 had more than one organ affected. There were a total of 234 injuries (123 liver, 99 splenic and 12 pancreatic) in these patients. A total of 160 injuries (75.8%) suffered blunt trauma. Of 211 patients, 157 underwent emergency CT with a median time to scan of 73 min (range 4-474). Hospitals provisionally designated as MTCs were 9 min faster than non-MTCs in time to CT. There was no difference in time of day. Ninety-nine patients had surgery within 24 h at a median time of 200 min. Twenty-five patients with hypotension on presentation took a median time of 130 min. Only 44 patients (27%) had a CT or emergency surgery within the expected MTC target of 1 h. Thirty-nine patients required transfer to another centre. CONCLUSIONS: Current management of patients with abdominal trauma and haemodynamic instability remains sub-optimal in Scotland when compared to recognized performance indicators of CT and emergency surgery within 1 h. Implementation of a major trauma network in Scotland should improve access to emergency radiology and surgery and efforts to shorten current timelines should improve patient outcomes.

Evaluation of the effect of diagnostic methodology on the reported incidence of ventilator-associated pneumonia.

BACKGROUND: The optimal method for diagnosing ventilator-associated pneumonia (VAP) is controversial and its effect on reported incidence uncertain. This study aimed to model the impact of using either endotracheal aspirate or bronchoalveolar lavage on the reported incidence of pneumonia and then to test effects suggested from theoretical modelling in clinical practice. METHODS: A three-part single-centre study was undertaken. First, diagnostic performance of aspirate and lavage were compared using paired samples from 53 patients with suspected VAP. Secondly, infection surveillance data were used to model the potential effect on pneumonia incidence and antibiotic use of using exclusively aspirate or lavage to investigate suspected pneumonia (643 patients; 110 clinically suspected pneumonia episodes). Thirdly, a practice change initiative was undertaken to increase lavage use; pneumonia incidence and antibiotic use were compared for the 12 months before and after the change. RESULTS: Aspirate overdiagnosed VAP compared with lavage (89% vs 21% of clinically suspected cases, p<0.0001). Modelling suggested that changing from exclusive aspirate to lavage diagnosis would decrease reported pneumonia incidence by 76% (95% CI 67% to 87%) and antibiotic use by 30% (95% CI 20% to 42%). After the practice change initiative, lavage use increased from 37% to 58%. Although clinically suspected pneumonia incidence was unchanged, microbiologically confirmed VAP decreased from 18 to 9 cases per 1000 ventilator days (p = 0.001; relative risk reduction 0.61 (95% CI 0.46 to 0.82)), and mean antibiotic use fell from 9.1 to 7.2 antibiotic days (21% decrease, p = 0.08). CONCLUSIONS: Diagnostic technique impacts significantly on reported VAP incidence and potentially on antibiotic use.

The insulation provided by infants' bedclothes.

The insulation provided by bedclothes of given thermal resistance (tog value) depends on the size of the body insulated. For simple shapes, discs, strips and cylinders, it is always less than the tog value. If the trunk and limbs of a baby are considered to be thermally independent cylinders, each with the bedclothes well tucked in, the net insulation, I, in tog units, is described by (1/I) = 0.6/Ib + 0.3/Im + 4.5/G, where Ib is the tog value of the bedclothes, Im that of the mattress and G the girth of the trunk in centimetres. I is reduced if the cot is small, if occupation has been belief, and if the bedclothes are loosely draped over the baby. I is increased (perhaps 2.5 times) if the baby curls up tightly. It is concluded that there is little risk of overinsulating a normal baby whose posture is not restricted, but a combination of fever and thick bedclothes might be dangerous.

An estimation of intracranial blood flow in the new-born infant.

1. A non-invasive method for the estimation of the intracranial blood flow of the new-born infant is described, and results obtained with it are presented. 2. The technique is a novel application of the principle of blood flow measurement by venous occlusion plethysmography. It is possible to apply a plethysmographic technique to the neonatal cranium because the presence of open sutures between the component bones permits small, but readily measurable, changes in intracranial volume to occur. 3. Skull volume changes are calculated from changes in the occipito-frontal circumference of the cranium as recorded and measured with a mercury-in-Silastic strain gauge. 4. The jugular veins in the baby's neck are occluded by finger pressure and there follows an increase in skull volume, which is rapid at first, but which decreases exponentially as venous drainage diverts to non-occluded channels such as the vertebral venous plexus. At the instant of jugular occlusion the rate of skull volume increase is representative of the rate of flow in the jugular vessels prior to occlusion, and so provides an index of the relative magnitude of the intracranial blood flow. The method thus allows changes in intracranial blood flow to be followed. When occlusion is released cranial volume decreases, initially rapidly, but slowing exponentially as resting volume is regained. 5. A theoretical model of the events occurring during the inflow and outflow phases has been developed, and a formula derived which allows an estimation to be made of the flow of blood through uncompressed channels. The measured value of jugular blood flow can then be augmented to an estimate of total intracranial flow. 6. The mean cerebral blood flow of sixteen normal babies was estimated to be 40 ml. 100 g-1.min-1 (S.D. = +/- 11.63).

The relation between sweat rate and weight loss when sweat is dripping off the body.

1. The relation between the rate of sweat production, S, and the rate of weight loss, W, has been examined under conditions in which the rate of evaporation was small.2. S could be found from W provided that a film of liquid was maintained over the skin surface. This could be achieved initially by immersing the subject in water containing detergent. Thereafter the film was maintained so long as the rate of weight loss exceeded about 10 g/min.3. When the rate of weight loss was changing and the rate of evaporation was constant, S could be calculated as W + 2.5 W.4. When the subject was constantly sprayed with water while being weighed, the correction for W became negligible. In this case there was no lower limit to the sweat rate which could be measured, but spraying considerably reduced the accuracy of the measurement.5. The output of sweat from a ventilated capsule on the forearm correlated well with estimates of central sweating drive based on weight measurements corrected for hidromeiosis.

The effects of soaking the skin in water at various temperatures on the subsequent ability to sweat.

1. The ability of two human subjects to produce sweat was measured before and after immersion for up to 4 hr in water at 32-36 degrees C (soak).2. The ability to produce sweat declined about 4 times as rapidly when the subject was soaked at 36 degrees C as at 32 degrees C.3. The rate of decline characteristic of soaking at 36 degrees C was shown by subjects exercising in water at 35 degrees C, but not at rest at 35 degrees C. The difference appeared to be related to the presence or absence of moderate sweating (300 g/hr) during the soak. At higher rates there was no further increase in the rate of decline.4. Soaking at 39 degrees C for 5 min, after which the water temperature was reduced to 33 degrees C, caused a decline consistent with the supposition that while the subject was sweating the rate of decline was the same as that at 36 degrees C and for the rest of the time the same as that at 32 degrees C.5. It is concluded that the rate of decline is increased if the sweat ducts are perfused, and some possible mechanisms are discussed.