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Biomedical subjects

R C Goode

Publications and source records attributed to R C Goode.

36 records · Page 2Linked to original sources
PubMed1977

Hearing under stress: II. Effect of hyperventilation and hypercapnia on speech discrimination.

Changes in the ability to discriminate speech from a eucapnic state to hyperventilation and hypercapnia were investigated. Standard speech audiometric techniques were employed to determine the speech reception threshold and the speech discrimination values, while respiratory conditions were varied and measured utilizing a mixed-gas breathing method. Respiratory parameters were similar to those encountered in aircraft personnel who experience oxygen/pressure system malfunction. The results of the study suggest no significant change in the speech reception threshold while in a hyperventilated or hypercapnic state. The speech discrimination results, however, suggest a significant performance decrement while in a state of hyperventilation.

Auditory Perception↗
PubMed1975

Sudden cold water immersion.

Cold water is known to facilitate the drowning process. To gather information on the possible relationship between ventilation and cold stimuli, measurements of inspired and expired breath by breath ventilation and alveolar PCO2 were made on 8 male subjects suddenly immersed in both cold (11 degrees C) and warm water (28 degrees C). The mean ventilation for all subjects for the 1st three breaths following cold water immersion was 94.5, 71.3 and 94.6 L/min (BTPS) as compared to 60.0, 36.2 and 38.5 L/min (BTPS) for warm water immersion. Alveolar CO2 fell dramatically in cold water from a pre-immersion mean value of 36.4 torr to 23.9 torr, whereas there was only a change associated with the first few breaths following immersion in warm water. In prolonged cold exposure, ventilation was still markedly above that observed in warm water after 5 min. There was no relationship between skin fold thickness and ventilatory response over the period studied. A large increase in ventilations is likely to result in inefficient swim stroke mechanics. This, combined with a high probability of inspiration of water, may contribute to death as a consequence of cold water exposure.

Adult↗
PubMed1971

The effects of hypercapnia, hypoxia and ventilation on the baroreflex regulation of the pulse interval.

1. The effects of moderate degrees of hypercapnia in hypoxia and in hyperoxia on the baroreceptor-cardiodepressor reflex have been studied in nine normal men.2. The beat-by-beat relation between pulse interval (I) and systolic pressure (P) during transient elevations of arterial pressure induced by intravenous injections of angiotensin II and phenylephrine was used to assess the sensitivity (DeltaI/DeltaP) and setting (I at a single reference arterial pressure) of the reflex.3. There was no consistent change in reflex sensitivity in any of the conditions studied.4. In hyperoxia (P(A, O2) approximately 200 torr) hypercapnia was associated with significant re-setting of the reflex in the direction of tachycardia. The extent of the re-setting was correlated with the degree of hypercapnia and with the accompanying increase in breathing.5. When hyperoxia with hypercapnia was replaced by hypoxia (P(A, O2) approximately 55 torr) with hypercapnia (which causes substantial arterial chemoreceptor activity), pulse interval at constant arterial pressure was further decreased.6. The tachycardia of hypoxia could not be accounted for by change of arterial pressure, P(A, CO2) or pulmonary ventilation, since it was most clearly demonstrable at constant values of pressure and either P(A, CO2) or ventilation.

Adult↗