Influence Of Patient Position Research Articles

Incidence of bradycardia during recovery from spinal anaesthesia: influence of patient position

We administered 0.5% plain bupivacaine 4 ml intrathecally (L2-3 or L3-4) in three groups of 20 patients, according to the position in which they were nursed in the post-anaesthesia care unit (PACU): supine horizontal, 30 degrees Trendelenburg or hammock position (trunk and legs 30 degrees elevated). Patients were observed until anaesthesia descended to less than S1. The incidence of severe bradycardia (heart rate < 50 beat min-1) in the PACU was significantly higher in patients in the Trendelenburg position (60%) than in the horizontal (20%, P < 0.01) or hammock (10%, P < 0.005) position. After 90 min, following admission to the PACU, only patients in the hammock position did not have severe bradycardia. In this late phase, the incidence of severe bradycardia in the Trendelenburg group was 35% (P < 0.005) and 10% in patients in the supine horizontal position. In four patients, severe bradycardia first occurred later than 90 min after admission to the PACU. The latest occurrence of severe bradycardia was recorded 320 min after admission to the PACU. We conclude that for recovery from spinal anaesthesia, the Trendelenburg position should not be used and the hammock position is preferred.

Influence of patient position on withdrawal forces during removal of lumbar extradural catheters

We have investigated the force required to remove lumbar extradural catheters from 88 parturients to determine the effects of patient positioning at removal, relative to the position at insertion. Parturients were allocated randomly to one of four groups: LS (lateral insertion, sitting withdrawal), LL (lateral insertion, flexed lateral withdrawal), SL (sitting insertion, lateral withdrawal) or SS (sitting insertion, sitting withdrawal). In both positions, the lumbar spine was kept maximally flexed. The force required to remove the catheter was measured at withdrawal. We found that the withdrawal force was influenced by the relationship between the position at removal and that at insertion, and we recommend that for ease of removal, patients should be placed in the same position as they were at the time of insertion. Compared with all other groups, the withdrawal force in patients in group LS was significantly greater (P < 0.05).

In vivo and in vitro precision for bone density measured by dual-energy X-ray absorption

An investigation was made into some of the major sources of error influencing the bone mineral density (BMD) measurements of the lumbar vertebrae, the femoral neck and the greater trochanter. The effect on accuracy and reproducibility of the following parameters was investigated: influence of patient positioning, patient size, scan speed, the technique of scan analysis and the temporal variation in instrument performance. The in vitro precision, both long-term and short-term, was assessed using aluminium phantoms supplied by the manufacturer. For the spine phantom, the precision expressed as a percentage coefficient of variation (%CV) was found to be 0.4% (10 scans) in the short term and 0.55% (15 scans) in the long term. Measured precision (short-term) for the three regions of the femur phantom analysed by the software was 1.3% for the neck of femur, 1.7% for Ward's triangle and 0.6% for the trochanter. Long-term precision was 1.0%, 1.9% and 1.1% respectively. No statistically significant difference was found between long- and short-term results. Short-term in vitro precision on a low density anthropological phantom was 4.1%, 4.2%, 2.4% and 0.61% for neck of femur, Ward's triangle, trochanter and spine respectively. In vivo short-term precision for the lumbar spine (L2-L4), measured by scanning four normal volunteers five times in one session, was found to be 0.8 +/- 0.25%. In vivo precision for the femur, measured on seven volunteers was 1.6 +/- 0.8% for the neck of femur, 3.2 +/- 1.7% for Ward's triangle and 2.2 +/- 1.1% for the trochanter.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of patient position on atmospheric pollution with halothane during out-patient dental anaesthesia

Influence of patient position on atmospheric pollution with halothane during out-patient dental anaesthesia

Isotope Renography with Special Reference to Reproducibility and Significance of Patient Position

The reproducibility of the three parameters used in isotope renography (T/2 = time from the maximum until half the radioactivity over the kidney had been attained; t = time from injection until the maximum value was attained; and the maximum value) was studied in 41 patients by repeat tests in the same position. The influence of patient position to the same three parameters was also studied in 61 patients investigated in sitting and prone position. The values could be reproduced in 70–98% of the patients in the same position with a fairly wide definition of the concept reproducibility. Patient position was of no significance to the reproducibility. When changing from the sitting to the prone position, the maximum value decreased, while T/2 and t did not show any systematic alteration. A disparity between the function of the two kidneys was demonstrated with the same frequency in the sitting and prone position. This disparity between the two sides was more easily reproducible when X-ray examinations revealed unilateral renal disease. It is concluded that the reproducibility in isotope renography is not fully satisfactory. In the event of a disparity between the two sides the test should be repeated, and if there is a clinical or radiological suspicion of unilateral renal disease, one normal isotope renography should not be relied on, but the test repeated.