[Classic high score literature reading] Under the action of spontaneous breathing, volatile anesthetics can maintain tidal volume and minute ventilation better than propofol

Volatile anesthetics maintain tidal volume and minute ventilation to a greater degree than propofol under spontaneous respiration.
Volatile anesthetics maintain tidal volume and minute ventilation better than propofol under spontaneous respiration.
Concepts related to MAC ①MAC: The lowest alveolar concentration of inhalation anesthetics that can make 50% of patients have no response to standardized stimuli (such as skin incision), about 1MAC
.

②MAC awake95: The alveolar gas anesthetic concentration when 95% of patients can open their eyes to simple instructions MACawake = 0.
4 MAC ③ED50 (half effective dose): the dose that causes 50% of the positive response (qualitative response) or 50% of the maximum effect (quantity response) Or concentration
.

1.
Background Although systemic anesthetics inhibit spontaneous breathing, the comprehensive effect of systemic anesthetics on respiratory function is still unclear
.

Objective To investigate the effect of general anesthetics on spontaneous respiration in different types and doses of non-intubated mice
.

2.
Methods Adult C57BL/6J mice were injected intravenous anesthetics (propofol and etomidate), inhalation anesthetics (0.
5, 1.
0, 2.
0 MAC/ED50 sevoflurane and isoflurane) to reduce the righting reflex
.

Whole body plethysmography (WBP) was used to measure respiratory parameters without tracheal intubation
.

At the same time, the change of the patient's respiratory sensitivity to CO2 under general anesthesia was measured
.

Continuously record the following respiratory parameters during anesthesia or CO2 exposure: respiratory rate (FR), tidal volume (TV), minute ventilation (MV), expiratory time (TE), inspiratory time (TI), inhalation-exhalation Time ratio (I/E) and peak inspiratory frequency
.

3.
Results Sevoflurane or isoflurane at a subanaesthetic concentration of 0.
5MAC increased respiratory rate (FR), tidal volume (TV), and minute ventilation (MV)
.

Under sevoflurane or isoflurane anesthesia, as the concentration of CO2 increases, respiratory rate (FR), tidal volume (TV), and minute ventilation (MV) decrease
.

Propofol and etomidate cause respiratory depression, which is manifested as a decrease in inhalation frequency (FR), tidal volume (TV), and minute ventilation (MV)
.

During ventilation with pure oxygen (100% O2), the respiratory rate (FR) of propofol and etomidate receiving 1.
0ED50 were 69.
63±33.
44 breaths/min and 55.
68±64.
42 breaths/min, respectively
.

In 3% CO2 ventilation, the rates were 88.
72±34.
51 beats/min and 225.
10±59.
82 beats/min
.

In 5% CO2 ventilation, they were 144.
17±63.
25 beats/min and 197.
70±41.
93 beats/min
.

Compared with the propofol group, the etomidate group mice were more sensitive to CO2
.

Compared with the same dose of etomidate, sevoflurane and isoflurane, propofol caused a greater decrease in respiratory rate (FR), minute ventilation (MV), and inspiratory-expiratory time ratio (I/E) Big
.

4.
Conclusion The regulation of spontaneous breathing by general anesthesia is different
.

Inhalational anesthetics increase respiratory rate (FR), tidal volume (TV), and minute ventilation (MV) at sub-anaesthetic concentrations, while suppressing these respiratory parameters at higher concentrations
.

Propofol inhibited respiratory parameters more than etomidate
.

5.
Figure & Table F1.
MAC comparison of sevoflurane and isoflurane F2.
The effect of sevoflurane on respiratory function is dose-dependent F3.
The effect of isoflurane on respiratory function is dose-dependent F4.
Intravenous anesthetics on respiration in vivo Effect of reaction F5F6END