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Biomedical subjects

M A Carpenter

Publications and source records attributed to M A Carpenter.

66 records · Page 4Linked to original sources
PubMed1976

Mechanism of dilutional anemia in massive splenomegaly.

Twenty patients with anemia and massive splenomegaly were studied in order to elucidate the mechanism by which splenomegaly results in plasma volume expansion. In 18 patients, increased plasma volume accounted for most of the anemia. Fourteen patients had an exaggerated renin response to standing, mean 1967 +/- 613 (SE) ng angiotensin ll/100 ml plasma (p less than 0.05). The mean resting forearm blood flow was increased 3.47 +/- 0.32 (SE) ml/100 ml forearm tissue (p less than 0.001). The venous capacitance was normal, as contrasted to a marked decrease in venous capacitance in patients with anemia of comparable degree without splenomegaly. Cardiac indices were increased in 10 of 11 patients (range 4.1-8.1 liters/min/sq m). In nine of ten patients oxygen consumption was increased (range 147-231 ml/min/sq m). Splenectomy was performed on 14 patients. Splenic blood flow was elevated in four of four patients (range 750-2000 ml/min). Splenic A-V oxygen difference was exaggerated in seven of seven patients and in three of three patients splenic indocyanine-green dye dilution curve failed to show an early peak suggestive of A-V shunting in the spleen. Free portal pressure was elevated in 12 of 12 patients and decreased immediately after splenectomy. The intravascular albumin mass decreased in ten patients, was unchanged in three at 2-4 mo after splenectomy, and was accompanied by a rise in the plasma albumin concentration in nine. These data suggest that a flow-induced portal hypertension with expansion of the portal vascular space is an important early hemodynamic change. This finding, together with a decreased peripheral resistance, probably results in a decrease in effective intravascular volume, resulting in stimulation of the renin-angiotensin-aldosterone system and other renal hemodynamic changes necessary for salt and water retention. Splenectomy usually accomplishes a complete reversal of these abnormalities and correction of the anemia.

Anemia↗
PubMedDate not supplied

Intelligibility of stops and fricatives in tracheoesophageal speech.

UNLABELLED: Listener accuracy in identifying voiced and voiceless stops and fricatives in tracheoesophageal (TE) and laryngeal speech were compared. Sixteen TE and ten laryngeal speakers produced ten phonemes embedded in a nonsense word in a carrier phrase. Four experienced listeners phonetically transcribed the experimental phonemes. As expected, perceptual error rates were higher for the TE samples for all comparisons completed. The dominant error for laryngeal samples was a misperception of manner of production. The dominant error for TE samples was a perception of voiced for voiceless phonemes. Such voicing misperceptions occurred more frequently for fricatives than stops. Previous studies have implicated the vibratory characteristics of the pharyngoesophageal (PE) segment for the voicing errors in TE speech. However, PE features would not fully explain why stops were less affected than fricatives and why the expected error was reversed for two TE phonemes (perceptions of voiceless for voiced consonants). LEARNING OUTCOMES: (1) As a result of this activity, the participant will be able to identify the most common listener misperceptions of tracheoesophageal speech. (2) As a result of this activity, the participant will be able to discuss possible reasons for the predominant error that occurs.

Aged↗
PubMedDate not supplied

The process of ethical decision making in psychiatric nursing practice.

The process by which nurses make ethical decisions in clinical practice has significance for the practitioners, educators, and administrators concerned with professional standards and quality of care. Twenty nurses participated in semistructured interviews during which they discussed ethical problems of their choice that had occurred in their clinical practice. Content analysis of interview transcripts revealed a 10-stage process used in ethical decision making. The process begins with an emotional response on hearing of an event that affects clinical practice and ends in an aftermath that includes feelings, talking with others, reconsiderations, and change or vows to change. The study identifies both affective and cognitive components of the decision-making process. The importance of the emotional aspect of ethical decision making, absent from previous studies, is recognized and evaluated. Implications based on the study suggest that the problems of ethical decision making may be a significant part of the stress in nursing. In addition, there is evidence that the process of ethical decision making affects nurses' views of self and of the profession and may have direct bearing on their leaving nursing for another professional career.

Adult↗