Canadian Journal of Anesthesia, Vol 7, 2-15, Copyright © 1960 by Canadian Anesthesiologists' Society

Posture and Anaesthesia

¹ Department of Anesthesiology, Hartford Hospital, Hartford, Conn

The effects of posture on respiration may include changes in pulmonary blood volume, changes in the compliance of the lunges, changes in the intrapulmonary distribution of the inspired air, and limitations in the expansion of the lungs from simple mechanical interference with the normal diaphragmatic movement, the lateral expansion of the chest, and the anteroposterior expansion of the chest. These effects are reflected by the decreased vital capacity and decreased tidal vollume seen in the various surgical postures, and in time lead to fatigue of the respiratory muscles and hypoventilation.

The effects of posture on circulation during anaesthesia are due to vasodilatation, obtundation of compensatory cardiovascular reflexes, peripheral pooling of blood, and, in certain positions, actual obstruction to flow. the deleterous nature of these effects is increased by increased depth of anaesthesia, and is particularly apparent when the position of the patient is changed during anaesthesia.

The effects of posture on the skeletal, muscular, and peripheral nervous systems are due to stresses, strains and stretches of ligaments, muscles, or nerves.

The respiratory deptession inherent in many of the surgical postures can be offset by the combined use of an endotracheal tube and assisted of contrilled respirations.

The danger of cardiovascular collapse when the patient is moved during anaesthesia can be largely avoided by moving the patient slowly, gently, and smoothly.

The possibility of muscle aches or pains and nerve injuries following the use of the various surgical postures can be lessened by proper use of the position demanded by the specific operative procedure.

Note:

Presented before the Sectional Meeting of the American College of Surgeons, Montreal, P.Q., April 6, 1959.