Biomedical subjects

Heidi Simpson

Publications and source records attributed to Heidi Simpson.

3 recordsLinked to original sources

PubMedDate not supplied

Interpretation of arterial blood gases: a clinical guide for nurses.

Arterial blood gas analysis has become an essential skill for all healthcare practitioners. It provides important information with regard to adequacy of ventilation, oxygen delivery to the tissues and acid-base balance. Although each patient's clinical presentation will be judged individually, situations that warrant analysis of a blood gas sample include respiratory compromise, post-cardiorespiratory arrest, evaluation of interventions such as oxygen therapy, respiratory support and as a baseline before surgery. This article reviews the different parameters that are measured by various machines, with a focus on basic measurement of arterial blood gases. These include partial pressure of carbon dioxide in arterial blood (PaCO(2)), partial pressure of oxygen in arterial blood (PaO(2)), bicarbonate levels (HC0(3)(-)) in arterial blood and base excess/deficit. The physiology of acid-base balance is reviewed and the causes and presentation of the four acid-base disturbances is described. A systematic method to aid arterial blood interpretation is identified, together with discussion regarding the importance of interpreting PaO(2) readings in relation to the amount of inspired oxygen a patient is receiving (FiO(2)), the practice of temperate correction and the relationship between standardized and actual bicarbonate readings.

Acid-Base Imbalance↗

PubMedDate not supplied

A comparison of two methods of blood pressure measurement.

In current practice, a two-stage approach to measuring blood pressure (BP) has been widely accepted as the most accurate and reliable method. However, by changing the local haemodynamics, this procedure might alter the blood pressure. In a study of 39 subjects, blood pressure was measured using two indirect methods (two-stage and one-stage approaches). Results showed no statistically significant difference in values for systolic blood pressure obtained from the two methods. Statistically significant lower diastolic blood pressure values were obtained using the two-stage compared to the one-stage approach. It is proposed that initial inflation of the cuff to estimate systolic blood pressure in the two-stage approach might lead to reactive hyperaemia and, therefore, a lower diastolic value. This two-stage approach might not provide the accurate readings it claims, and in addition it requires more time and subjects the patient to longer periods of stress.

Adolescent↗

PubMedDate not supplied

Respiratory assessment.

The ability to carry out and document a full respiratory assessment is an essential skill for all nurses. The elements included are: an initial assessment, history taking, inspection, palpation, percussion, auscultation and further investigations. A prompt initial assessment allows immediate evaluation of severity of illness and appropriate treatment measures may warrant instigation at this point. Following this, a comprehensive patient history will be elicited. Clinical examination of the patient follows and involves inspection, palpation, percussion and auscultation. At this point, consideration must be given to preparation of a light, warm, quiet, private environment for examination and suitable patient positioning. Inspection is a comprehensive visual assessment, while palpation involves using touch to gather information. The next stages are percussion and auscultation. While percussion is striking the chest to determine the state of underlying tissues, auscultation entails listening to and interpreting sound transmission through the chest wall via a stethoscope. Finally, further investigations may be necessary to confirm or negate suspected diagnoses.

Auscultation↗