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Biomedical subjects

M L Ryan

Publications and source records attributed to M L Ryan.

3 recordsLinked to original sources
PubMed1992

Lung mechanics and oxygen consumption during spontaneous ventilation and severe heart failure.

The effects of acute heart failure on lung mechanics and oxygen consumption (VO2) during normocarbic spontaneous ventilation were studied in 21 anesthetized pigs. Heart failure severe enough to double oxygen extraction (O2ex) was induced with intravenous esmolol boluses and infusion. Compared to normal, the inspiratory elastic work of breathing (Wel) increased from 335 +/- 371 (mean +/- SD) to 559 +/- 48 mm Hg.ml (p less than 0.003) during heart failure, lung compliance (CL) fell from 121 +/- 144 to 22 +/- 15 ml/mm Hg (p less than 0.05), and respiratory power climbed from 140 +/- 200 to 245 +/- 214 mm Hg.ml.min-1 (p less than 0.002). These mechanical changes were accompanied by a decrease in both VO2 (221 +/- 61 to 191 +/- 50 mlO2/min, p less than 0.05) and oxygen delivery (DO2) (680 +/- 240 to 260 +/- 90 mlO2/min, p less than 0.004). The VO2/DO2 ratio doubled (p less than 0.0002), confirming increased O2ex. In conclusion, severe acute heart failure decreased CL, and increased Wel and respiratory power significantly. The depressed cardiac output limits both DO2, and to some extent, VO2. However, a greater proportion of the delivered O2 is consumed, supplying indirect evidence which suggests that the respiratory muscles' VO2 increases as a consequence of increased power expenditure.

Acute Disease↗
PubMed1991

Evaluation of direct pharmacist intervention on conversion from parenteral to oral histamine H2-receptor antagonist therapy.

A program in which pharmacists were authorized to change parenteral histamine H2-receptor antagonist (H2RA) therapy to the oral route without first contacting the prescriber was evaluated on cost and appropriateness of use of the parenteral route. Parenteral therapy was received by 264 and 244 patients in the study and comparison groups, respectively. Length of parenteral H2RA therapy was less in the study group (4.8 vs. 7.5 d) as was length of total (parenteral + oral) therapy (8.4 vs. 12.1 d). Parenteral H2RA drug acquisition savings were $6225 in the six-week study period or $53,950 when annualized. Decreased oral therapy contributed additional savings. There was a significant decrease in the number of inappropriate parenteral doses of ranitidine per patient, the drug used in more than 80 percent of the patients. In addition to the direct effect of pharmacists' interventions, there appeared to be an indirect effect of the program, as physicians initiated route of administration changes on their own.

Administration, Oral↗