Ventilatory Pattern and Chest Wall Mechanics during Ketamine Anesthesia in Humans

Respiratory mechanics and morphometric changes during anesthesia with ketamine in normal rats

“…Functional residual capacity remained unchanged in our study (CTRL: 1.89 ± 0.39 ml vs KET: 2.14 ± 0.65 ml), in agreement with some reports indicating that ketamine is unique in its ability to maintain FRC upon the induction of anesthesia (21,22). , E,rs and , E,L increased significantly during ketamine anesthesia (Table 1), suggesting that lung (and thus respiratory system) viscoelasticity/inhomogeneity became more prominent under the action of this anesthetic agent.…”

Perioperative functional residual capacity

“…An initial reduction of approximately 200 ml occurs during the injection of thiopentone, coincident 20 with the loss of consciousness. With ketamine, however, no change in FRC occurs in either adults, 24 reduction, whereas FRC will be reduced by about 20% if methohexitone induction is followed by tracheal intubadon, 27 particularly if coughing occurs during intubation. 27 The magnitude of reduction varies considerably and is primarily determined by body build, t J-~,~ In the morbidly obese, FRC can be as low as 50% of awake values.…”

Effects of Anesthetics, Sedatives, and Opioids on Ventilatory Control

“…Ketamine caused small increases in FRC (+195 mL with ketamine), MV (+ 2.6 liter/min), TV (+79 mL), and respiratory rate [+2 breaths per minute (BPM)]. There was a statistically significant increase in rib cage contribution to TV from 34% (awake) to 52% during ketamine (the increase in FRC and the dramatic increase in rib cage contribution to TV is highlighted in figure 4 in the 1986 Mankikian et al paper (406)). Compared to volatile anesthetics ketamine clearly spared intercostal respiratory muscle activity.…”

“…Intercostal muscle activity appears to be preserved or even recruited and there is a relative increase of the rib cage contribution to TV in contrast to inhalational agents (715,745,747). Manikikian et al (406) measured FRC with the helium dilution method and tracked the breathing pattern with linear transformer belts in 14 healthy patients. They used a 3 mg/kg bolus of ketamine followed by an infusion of 20 μg/ kg/min for maintenance with the patients breathing 40% O 2 in air.…”