What question did this study set out to answer?

October 1, 1975Scandinavian Journal of Clinical and Laboratory Investigation

Sinus Arrhythmia in Man: Influence of Tidal Volume and Oesophageal Pressure

View Full Paper

Ask AI

Bookmark

Why the study?

Does varying tidal volume and intrathoracic pressure influence respiratory sinus arrhythmia in healthy subjects?

Population

Healthy subjects

Comparison

Varying tidal volume at a standardized slow… vs Baseline or different respiratory cycles

Design

Other

Authors

UFU. FreyschussKarolinska University Hospital AMA. MelcherKarolinska University Hospital

Discussion

Member takes

Implication

Supports cardiovascular reflex mediation of RSA in healthy subjects; leaves open applicability to clinical populations or disease states.

Key Points

The study aimed to examine how tidal volume and intrathoracic pressure influence respiratory sinus arrhythmia in healthy individuals.
Healthy subjects breathed into a spirometer with tidal volumes of 1, 1.5, and 2 liters at a rate of 6 breaths per minute.
Intrathoracic pressure was manipulated using negative inspiratory pressure and intermittent positive pressure ventilation.
Separate experiments involved applying negative pressure to the thorax.
Increased tidal volume resulted in greater respiratory sinus arrhythmia, indicated by marked heart rate fluctuations.
Higher oesophageal pressure led to a slight increase in respiratory sinus arrhythmia.
Intermittent positive pressure ventilation nearly abolished respiratory sinus arrhythmia, while intermittent negative pressure ventilation had no significant effect.

Structured PICO

Does varying tidal volume and intrathoracic pressure influence respiratory sinus arrhythmia in healthy subjects?

Population

Healthy subjects

Intervention

Varying tidal volume (1, 1.5, and 2 L) at a standardized slow respiratory rate (6/min) and varying intrathoracic pressure (negative inspiratory pressure of 5 cm H2O, intermittent positive pressure ventilation, and intermittent negative pressure ventilation)

Comparator

Baseline or different respiratory cycles (e.g., similar oesophageal pressure but different tidal volume)

Outcome

Respiratory sinus arrhythmia (RSA) amplitude and heart rate changessurrogate

Cardiovascular reflexes, rather than pulmonary stretch reflexes or central nervous mechanisms, appear to be the primary drivers of respiratory sinus arrhythmia in humans.

Cite This Study

Freyschuss et al. (1975) studied this question.

synapsesocial.com/papers/6a22563e71fe5424977c95d8 https://doi.org/10.3109/00365517509095772

View Full Paper

Ask AI

Bookmark

Sinus Arrhythmia in Man: Influence of Tidal Volume and Oesophageal Pressure

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Sinus Arrhythmia in Man: Influence of Tidal Volume and Oesophageal Pressure

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider