Thoracic surgical patients are more likely than others to have increased airway reactivity and a propensity to develop bronchoconstriction. (Many of these patients are cigarette smokers and have chronic bronchitis or COPD.) In addition, surgical manipulation of the airways and bronchial tree by instruments, a DLT, or the surgeon makes bronchoconstriction more likely to occur.
The potent inhaled anesthetic agents have all been shown to decrease airway reactivity and bronchoconstriction provoked by hypocapnia or inhaled or irritant aerosols. Fentanyl does not appear to influence bronchomotor tone, but morphine may increase tone by a central vagotonic effect and by releasing histamine.
In most patients, anesthesia is safely induced with propofol or etomidate. In patients with reactive airways, ketamine may be the drug of choice for induction because it has a bronchodilator effect.
Propofol infusion in combination with remifentanil is probably the technique of choice for producing a stable OLV with no effect on hypoxic pulmonary vasoconstriction (HPV).
In deciding between intravenous (IV) versus potent inhaled agent for anesthesia during OLV, consideration should be given to their effects on inflammatory alterations in the deflated lung. (Ventilation with increased tidal volumes and pressures can produce an proinflammatory reaction in the nondeflated, ventilated lung.)
The neuromuscular blocking drugs of choice for thoracic procedures are those that lack a histamine-releasing or vagotonic effect and that have some sympathomimetic effect (pancuronium, vecuronium, rocuronium).