Charlie Bryan Symposium
Ventilation Without Breathing:
Physiological Implications
Arthur S. Slutsky, MD
St. Michael’s Hospital;
Interdepartmental Division of Critical Care
Medicine,
University of Toronto
Charlie Bryan
Overview
 Historical perspective
 Review techniques using
 Physiological insights
 Conclusions
constant flows
Aristotle (384 BC – 322 BC)
Pulsations in the blood system were due to
the respiratory process and that the heart just
moved as a result of the same breathing
process.
Galen (129 AD– c. 200)
Blood ebbs freely and the heart moves as
a result of breathing.
Robert Hooke (1667)
Robert Hooke, 1667
“.....This being continued for a pretty while, the dog
lay still as before, his eyes being all the time very
quick, and the heart beating very regularly,
Robert Hooke, 1667
“.....This being continued for a pretty while, the dog
lay still as before, his eyes being all the time very
quick, and the heart beating very regularly, but
upon ceasing this blast and suffering the lungs to
fall and lie still, the dog would immediately fall into
dying convulsive fits; but he is soon revived again by
renewing the fullness of the lungs.......”
Slutsky AS. Am Rev Resp Dis 1988;138:175-83.
Slutsky AS. Am Rev Resp Dis 1988;138:175-83.
Techniques of
Constant Flow
Techniques of Constant Flow Inflation

Techniques where constant flows decrease dead
space during ventilation
– Constant oxygen insufflation
– Tracheal gas insufflation

Techniques where constant flows used in apneic
patients
– Apneic Oxygenation
– Tracheal Insufflation of Oxygen
– Constant Flow Ventilation
Constant Flows in
Apneic Patients
Apneic Oxygenation
 Originally called
Diffusion Respiration
(Draper and Whitehead, 1940’s)
– Ventilation with 100% O2 to washout N2, then
O2 source at the airway opening
Apneic Oxygenation in Man
7
200
6.9
150
pH
PaCO2 (mmHg)
250
6.8
100
6.7
50
0
6.6
1
2
3
4
Patient Number
1
2
3
4
5
5
Patient Number
Frumin et al Anesthesiology 1959;20:789-98
How does Apneic Oxygenation Work?
Tracheal Insufflation of Oxygen



Paralyzed dogs
Constant flow at
~2l/min
Measure blood
gases
Apneic Oygenation
Constant Oxygen Insufflation
Slutsky et al. Anaesthesiology 1985;63:278-286
Constant Flow Ventilation
Lehnert, Oberdoster, Slutsky Journal of Applied Physiology 1982;53:483-489
J Clin Investigation 1991;87:1621-7
Shykoff, Naqvi, Slutsky J Clin Investigation 1991;87:1621-7
Constant Flow
Shykoff, Naqvi, Slutsky J Clin Investigation 1991;87:1621-7
Shykoff, Naqvi, Slutsky J Clin Investigation 1991;87:1621-7
Shykoff, Naqvi, Slutsky J Clin Investigation 1991;87:1621-7
Kato, Menon, Slutsky Circulation 77:407-14,1988
Kato, Menon, Slutsky Circulation 77:407-14,1988
Kato, Menon, Slutsky Circulation 77:407-14,1988
Kato, Menon, Slutsky Circulation 77:407-14,1988
Kato, Menon, Slutsky Circulation 77:407-14,1988
Kato, Menon, Slutsky Circulation 77:407-14,1988
Conclusions
Multiple techniques of ventilation with constant
flows
 Clinical utility varies with technique
– Apneic oxygenation – brain death
– Tracheal insufflation of Oxygen – mass casualties
– Constant flow ventilation – physiological tool
 Future utility of some of these techniques still
being investigated
