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Biomedical subjects

S V Rithalia

Publications and source records attributed to S V Rithalia.

34 records · Page 2Linked to original sources
PubMed1982

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↗
PubMed1981

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↗
PubMed1981

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↗
PubMed1981

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↗
PubMed1981

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↗
PubMed1980

Continuous tissue pH measurement in critically ill adults with a miniaturised glass electrode.

A continuously reading subcutaneous pH electrode has been developed which gives relatively stable readings when applied to any well perfused part of the body. The results obtained with this electrode have been compared with the actual pH of the arterial blood measured by conventional methods. Thirty patients were studied and one hundred and sixty three observations were made. The correlation coefficient (r) between tissue pH (pHt) and arterial pH (pHa) was 0.76 (P less than 0.01). The response time of the electrode in vitro was less than one minute and, in vivo, stabilization of the recording occurred in less than three minutes. It was found that the discrepancy between pHa and pHt gave a good indication of the adequacy of tissue perfusion.

Adult↗
PubMed1979

Characteristics of transcutaneous oxygen tension monitors in normal adults and critically ill patients.

The performance characteristics of two transcutaneous PO2 monitors were detailed in eleven healthy adults and eighteen critically ill patients (twelve following cardiopulmonary bypass). There was no significant difference in their performance when blood was used as the calibrating medium. In critically ill patients they proved to be of value for recording short term trends in arterial PO2 rather than for measuring absolute values.

Adult↗
PubMed1979

Evaluation of a simple device for regulating intravenous infusions.

Dial-A-Flo, an infusion control device, is assessed for accuracy, in vitro and in vivo. The unit did not permit accurate control and particularly so at lower flow rates. The normal spontaneous variations in venous pressure that occur around an infusion cannula tip, further increase the error of gravity-fed infusions. Dial-A-Flo has no advantage over a standard administration set alone, and should not be used for controlled administration of cardiac drugs.

Evaluation Studies as Topic↗
PubMedDate not supplied

Role of the clinical engineer in patient monitoring services.

The basic role of a clinical engineer is to provide safe and effective management and application of technology within patient care settings. In the UK the total number of such people is still relatively small. Clinical engineering as a profession requires a proper career structure and professional status. This can be achieved only by the support of a professional body such as the Biological Engineering Society.

Biomedical Engineering↗
PubMedDate not supplied

Developments in transcutaneous blood gas monitoring: a review.

Transcutaneous measurements of oxygen (tcPO2) and carbon dioxide (tcPCO2) are useful in the intensive care unit because they provide continuous and non-invasive estimation of arterial blood gases. In patients with compromised peripheral blood flow the cutaneous values will reflect the haemodynamic changes as blood is shunted away. They have been increasingly used in a variety of clinical situations, such as assessment of skin flap viability, drug evaluation, prediction of wound healing and selection of amputation level in peripheral vascular disease. From a review of available literature it appears that transcutaneous monitors have found another application as indicator of local tissue perfusion.

Animals↗
PubMedDate not supplied

Comparison of oscillometric and intra-arterial blood pressure and pulse measurement.

Non-invasive oscillometric blood pressure and pulse measured by an Omron HEM-703CP monitor were compared with arterial values obtained from direct measurements of the radial artery. An excellent correlation and agreement was found between the two methods (systolic r = 0.99; diastolic r = 0.97; pulse r = 0.99), although there was some variability among individual subjects. The range of difference between them was 0 to 10 mmHg for systolic and -6 to +5 mmHg for diastolic pressures. When tested on the bench using the Metron QA-1280 non-invasive blood pressure analyser the HEM-703CP monitor rarely exhibited errors exceeding 2-3 mmHg over a measurement range of 50-200 mmHg.

Adult↗