Preoperative corticosteroids for reactive airway?

IN this issue of the Journal, Silvanus et al. studied the effects of preoperative interventions in patients with reversible airway obstruction (RAO). This article raises the question of when corticosteroids may be useful to prevent an adverse perioperative outcome for the patient with RAO. The low frequency of adverse outcomes in anesthesia practice limits the ability of researchers to conduct prospective randomized controlled trials to identify best practices. This is certainly the case for adverse outcomes linked to reactive airways disease and anesthesia. Warner et al. looked at the population of patients with asthma who underwent surgery in Olmstead County, Minnesota, and found the incidence of adverse outcomes to be very low. On the other hand, we know from the American Society of Anesthesiologists Closed Claims study that severe bronchospasm occasionally leads to brain damage or death. Furthermore, the present author has repeatedly informally surveyed the audience at his American Society of Anesthesiologists refresher course on bronchospasm as to whether they had ever cared for a patient with what they believed was life-threatening bronchospasm under anesthesia. Although the results are certainly biased (because clinicians probably tend to go to a lecture on the topic after such an event), many audience members raise a hand in response to the question. Hence, severe bronchospasm seems to be a serious complication of low but finite incidence. Because of this low incidence of severe adverse outcomes, researchers interested in bronchospasm have tended to study the more common but less serious surrogate outcomes of increased respiratory resistance or audible wheezing. Audible wheezing occurred in 4% of patients intubated following an induction dose of thiopental, and reversible bronchoconstriction following intubation is probably the rule rather than the exception when assessed by respiratory resistance. Bronchospasm severe enough to require treatment probably occurs in the range of 1 in 250 patients anesthetized but is probably more prevalent in some populations with a high frequency of lung disease. We do not know, however, whether these phenomena can be linked to the rare severe outcome attributed to bronchospasm. Despite the absence of that link, it does seem reasonable to assume that reducing the incidence of mild bronchospasm is a useful goal. Silvanus et al. studied patients who were scheduled for surgery and who were found to have RAO during preoperative assessment. Only patients who had RAO and were not currently receiving treatment were studied. The patients tended to fit the criteria for chronic obstructive pulmonary disease to a greater extent than for asthma, as they had some evidence of limited vital capacity and their forced expiratory volume in 1 s appeared to reverse only moderately with treatment. The patients were divided into three groups: those who received no treatment other than albuterol just before induction and intubation, those who received 5 days of albuterol prior to intubation, and those who received 5 days of corticosteroid plus albuterol prior to intubation. The group receiving steroids had a much lower incidence of wheezing than did the other two groups. Should we be surprised that albuterol alone, while improving the forced expiratory volume in 1 s, did not prevent intubation-induced bronchoconstriction? Probably not. Patients may show marked improvement following albuterol when their airways are not provoked. However, the mechanical stimulus of intubation is a powerful provocation for bronchoconstriction that may unmask ongoing disease. This is probably analogous to a methacholine provocation test: a patient may have a normal forced expiratory volume in 1 s but still react to a stimulus. Does this study differ from previous studies documenting that albuterol alone markedly limits intubation-induced bronchoconstriction? Not really, because those studies were in unselected patients, whereas these patients had significant preexisting disease. Rather, this article suggests that in patients with documented reversible disease, it may be best to provide therapy beyond a beta agonist alone. How should this article affect our practice? We probably don’t see many patients with untreated disease as severe as these patients had. The mean forced expiratory volume in 1 s/forced vital capacity ratio of 55% seen in this study would generally be enough to bring someone to medical attention and treatment. Given a reversible component of airway obstruction, the National Heart Lung and Blood Institute Expert Panel on Asthma supports the use of antiinflammatory therapy. Hence, most patients with this degree of illness will likely already be receiving inhaled steroids. If they are not, this article certainly supports the benefits of adding a short course of oral corticosteroids preoperatively. Even if they are This Editorial View accompanies the following article: Silvanus M-T, Groeben H, Peters J: Corticosteroids and inhaled salbutamol in patients with reversible airway obstruction markedly decrease the incidence of bronchospasm after endotracheal intubation. ANESTHESIOLOGY 2004; 100:1052–7.