| Abstract: | Mathew, Oommen P. Effects of transient intrathoracicpressure changes (hiccups) on systemic arterial pressure.J. Appl. Physiol. 83(2): 371-375, 1997. The purpose of the study was to determine the effect oftransient changes in intrathoracic pressure on systemic arterialpressure by utilizing hiccups as a tool. Values of systolic anddiastolic pressures before, during, and after hiccups were determinedin 10 intubated preterm infants. Early-systolic hiccups decreasedsystolic blood pressure significantly (P < 0.05) compared with control(39.38 ± 2.72 vs. 46.46 ± 3.41 mmHg) and posthiccups values,whereas no significant change in systolic blood pressure occurredduring late-systolic hiccups. Diastolic pressure immediately after thehiccups remained unchanged during both early- and late-systolichiccups. In contrast, diastolic pressure decreased significantly(P < 0.05) when hiccups occurred during diastole (both early and late). Systolic pressures of the succeeding cardiac cycle remained unchanged after early-diastolic hiccups, whereas they decreased after late-diastolic hiccups. Theseresults indicate that transient decreases in intrathoracic pressurereduce systemic arterial pressure primarily through an increase in thevolume of the thoracic aorta. A reduction in stroke volume appears tocontribute to the reduction in systolic pressure. |
