Comparison of performance characteristics of the Nimbus and Airwave mattresses.
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Adult↗
Biomedical subjects
S V Rithalia
Publications and source records attributed to S V Rithalia.
Comparison of transcutaneous oxygen and carbon dioxide monitors in normal adults and critically ill patients.
The performance characteristics of two transcutaneous combined PO2 (tcPO2) and PCO2 (tcPCO2) sensors were compared with single tcPO2 and tcPCO2 electrodes in critically ill patients. The relationship between arterial blood gases (PaO2, PaCO2) and transcutaneous values was linear. Correlation coefficients (r) varied from 0.79 to 0.87 for tcPO2 and 0.92 to tcPCO2. The tcPO2 readings were always lower than PaO2 values, but the tcPCO2, with modified calibration of the electrodes, did not differ significantly from PaCO2. There was no significant difference of clinical importance in the performance of the three monitoring systems.
Adult↗
Effects of ambulation on the blood flow in paralysed limbs.
Non-invasive transcutaneous blood gas monitoring techniques have been used as indicators of the effect of standing exercise on circulation in paraplegic subjects. Oxygen (tPO2) and carbon dioxide (tPCO2) electrodes were positioned on the chests and legs of a group of normal control subjects and a group of paraplegic subjects in both rested sitting and post-ambulatory standing. It has been shown that, with one possible exception, there is no significant difference in the transcutaneous blood gas partial pressures of O2 and CO2, and thus, by inference, in the circulation of paraplegics when either sitting or standing.
Adolescent↗
Effect of intermittent pneumatic compression on lower limb skin perfusion.
Transcutaneous oxygen (tcPO2) and carbon dioxide (tcPCO2) measurements were used before, during, and after intermittent pneumatic compression (IPC) to assess lower limb skin perfusion in 21 healthy adult volunteers and 23 elderly patients. The temperature of the sensors was set at 44 degrees C during calibration and maintained throughout all tests. Resting tcPO2 was significantly lower (p less than 0.01) in patients than in controls. In all subjects tcPO2 decreased and tcPCO2 increased during compression. Patients showed a highly significant increase (p less than 0.001) in tcPCO2 during and after the treatment. Results of this study indicate that the symptomatic improvement, in peripheral vascular disease and wound healing following IPC, is not due to improved skin perfusion or enhancement of oxygenation and CO2 removal.
Aged↗
Never mind the volume, what about the flow rate?
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Humans↗
Effect of intermittent pneumatic compression on lower limb oxygenation.
The effect of intermittent pneumatic compression (IPC) of the lower limbs on transcutaneous oxygen tension (tcPO2) was studied in 14 healthy volunteers and the same number of elderly patients. The oxygen sensor was calibrated at 37C in room air. This temperature was also used for measurements. Compression pressure in the IPC garment was standardized to 50mmHg inflation and zero mmHg deflation. Cycle time was set to 30 seconds inflation and 30 seconds deflation. It was found that using this combination of pressure and cycle times, tcPO2 fell during compression in all subjects and returned to the precompression level after the treatment. Although reactive hyperemia of various intensities occurred in some subjects after compression, tcPO2 did not rise significantly above the resting level. This suggests that the symptomatic improvement reported by patients treated with IPC was more likely to be due to enhanced removal of metabolites and supply of nutrients than to an improvement in leg oxygenation.
Adult↗
Equipment standards in the ITU.
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Equipment and Supplies, Hospital↗
Clinical applications of continuous pH monitoring.
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Acid-Base Equilibrium↗
Characteristics of transcutaneous carbon dioxide tension monitors in normal adults and critically ill patients.
The performance of three electrodes used for transcutaneous carbon dioxide (tcPCO2) monitoring is compared in 15 healthy volunteers and 26 critically ill adults. All three electrodes showed good correlation between tcPCO2 and arterial blood PCO2 (PaCO2) with a correlation coefficient (r) greater than 0.86. There was little difference in the performance characteristics of the three monitors. They may be usefully employed to estimate PaCO2 values when used with a modified calibration recommended by the manufacturers.
Adult↗
Medical technology. Transcutaneous carbon dioxide monitoring.
Transcutaneous PCO2 electrodes are noninvasive, reliable, and accurate indicators of the trend in arterial PCO2. Their combination with occasional arterial sampling allows them to be calibrated in vivo for use in a wide range of patients, even in the presence of a severely compromised haemodynamic state. Their role in the ITU as monitors of continuous ventilation and during weaning has been established. However, their potential for use during anaesthesia, acute asthma, exacerbations of chronic airflow limitation, and in studies into the normal and abnormal mechanisms of ventilation during sleep has yet to be realized.
Animals↗
Continuous flush devices for vascular pressure monitoring.
Six different types of continuous flush devices have been assessed for accuracy in vitro and ease of use in vivo. Only two types of device matched the manufacturers' specifications of performance. The other four gave higher flow rates than expected.
Blood Pressure↗
Measurement of transcutaneous PCO2 in critically ill patients.
Transcutaneous carbon dioxide tensions (tcPCO2) measured with a heated electrode were compared with arterial carbon tensions (PaCO2) in 28 patients. Seventy-eight observations were made. At a skin electrode temperature of 44 degrees C the tcPCO2 was significantly higher than PaCO2 but changes in PCO2 detected by both measurements were closely correlated. The correlation coefficient between tcPCO2 and PaCO2 was 0.92 (P less than 0.001). The 90% response time of the electrode in vitro was less than 1 min, and in vivo stabilization of the recording occurred in less than 15 min. It was found that the transcutaneous PCO2 electrode can be employed usefully in intensive care monitoring of adult patients especially when weaning them from artificial ventilation.
Adult↗
The performance characteristics of an intra-arterial oxygen electrode.
The performance characteristics of intravascular oxygen electrodes used during and after open heart surgery are described. The pO2 recorded continuously by the electrodes correlated extremely well with corresponding measurements made on samples of arterial blood. The results show that intravascular pO2 electrodes are accurate and can be readily used during surgery and intensive care of adult patients.
Adult↗
A device for the routine measurement of plasma oncotic pressure.
Plasma colloid oncotic pressure (COP) is an important determinant of interstitial oedema and relates to mortality in critically ill patients. A simple device for the routine measurement of COP has been developed which gives stable readings in less than three minutes approximately 0.2 ml. of plasma. It is easy to calibrate, simple to use and has a short equilibration time.
Engineering↗
Changes in colloid osmotic pressure in patients undergoing cardiothoracic surgery.
Measurements of plasma colloid osmotic pressure (COP) were made during and for 24 h after normothermic continuous flow cardiopulmonary bypass (CPB) in 20 adults exposed to sudden haemodilution by a crystalloid pump prime solution. Haematocrit, albumin and total protein were also measured. Within 5 min of starting bypass the mean COP fell to 45% pre-bypass value and remained at this level until bypass was discontinued. Following bypass, the oncotic pressure rose rapidly during the first hour to 84% of the prebypass value, and then more slowly until it reached the pre-bypass value 24 h later. The trend seen for plasma proteins and haematocrit was similar but the fall was smaller, 65-70% of the pre-bypass values. This significant difference in fall between plasma protein concentration and directly measured COP is explained by their non-linear relationship. Three patients died soon after bypass. They all showed significantly lower values of COP than the mean for the group as a whole at some stage (P less than 0.05).
Adult↗
Continuous tissue pH and transcutaneous PO2 measurement as an index of tissue perfusion in critically ill patients.
Measurements of transcutaneous PO2 (tcPO2) and tissue pH (pHt) were compared with arterial values in 28 critically ill patients. Eleven of the patients were undergoing continuous flow cardiopulmonary bypass and the other 17 were admitted to the Intensive Therapy Unit (ITU) suffering from a variety of medical and surgical disorders. A total of 135 observations were made on the 28 patients. The overall correlation between the two sets of measurements was poor. The correlation coefficient (r) between arterial PO2 (Pa,O2) and tcPO2 was 0.41 (P less than 0.01) and between arterial pH (pHa) and pHt 0.67 (P less than 0.01). However, the value varied greatly in different groups of patients. In those patients with cardiopulmonary failure, the tcPO2 and pHt measurements rapidly and accurately reflected changes in peripheral tissue perfusion, by contrast the core-peripheral temperature deficit did not change significantly. It is concluded that the technique can be used as a sensitive index of peripheral blood flow and may have prognostic significance
Adult↗
Recent developments in infusion devices.
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Humans↗