Exposure to environmental tobacco smoke and the risk of adverse respiratory events in children receiving general anesthesia.

Skolnick ET, Vomvolakis MA, Buck KA, Mannino SF, Sun LS. Anesthesiology. 1998; 88:1144-55. [

see abstract below ]

Adverse anesthesia events in children exposed to environmental tobacco smoke. (Editorial)
Koop CE. Anesthesiology. 1998; 88:1141-2.
No abstract available

Few topics have received more publicity in the general media than the putatively harmful effects of exposure to "second-hand smoke". On the grounds of this issue, an increasingly powerful anti-smoking lobby is waging a fight to the finish against a retreating tobacco lobby. Meanwhile, we watch with bated breath.....

Those who travel outside the United States quickly become aware of the enormous social, cultural and legal restrictions on tobacco smoking that have evolved in this country over the last two decades. In the developing world and in many countries in Europe, however, we find that the air is still thick with second-hand smoke in virtually every restaurant and public place. On their return to the pristine shores of the US of A, many a nonsmoking traveler gulps in smoke-free air with relief. However, millions of Americans continue to smoke at home, and their children do not have the liberty of retreating to a smoke-free environment within the home.

Exposure to environmental tobacco smoke in children has been implicated in decreased lung growth, impaired lung mechanics, worsened asthma, airway hyperreactivity and more frequent lower respiratory tract infections. In the May issue of Anesthesiology, Eric Skolnick and his colleagues at Columbia University report on a prospective, blinded study they performed on 602 children of smoking and nonsmoking parents at the Babies and Children's Hospital of New York. They specifically examined the detrimental effects of environmental tobacco smoke exposure ("passive smoking") on airway complications in children aged between one month and twelve years undergoing general anesthesia. In addition to a questionnaire about parents' smoking habits, they utilized an objective marker of exposure to passive smoke: the urinary concentration of the major metabolite of nicotine, cotinine. Cotinine has a half-life of 19 - 40 hr in nonsmokers and allows detection of exposure to tobacco smoke within the previous 3-4 days.

General anesthesia consisted of halothane administered in 65-70% nitrous oxide and oxygen. About four-fifths of the patients required endotracheal intubation, approximately one-fifth received supplemental intravenous fentanyl, and about half were given a regional or local block for postoperative analgesia. Airway complications were defined as laryngospasm, wheezing, bronchospasm requiring treatment, increased peak airway pressure, stridor, breath holding, severe coughing at induction or emergence, excessive mucus production requiring suctioning, and perioperative oxygen desaturation to an SpO2 of <95%, or SpO2 <97% after oxygen therapy was terminated in the recovery room once the child was fully awake.

The authors found a direct relationship between the incidence of airway complications and the level of cotinine in the patients' urine. A high concentration of cotinine (>40 ng/mL) was associated with a 42% incidence of airway complications, whereas a low concentration of cotinine (<10 ng/mL) was associated with a 24% incidence of airway complications. A moderate concentration was associated with an intermediate incidence of airway complications. This relationship also correlated to the parents' smoking history (high: >30 cigarettes/day, low: nonsmokers).

Interestingly, female children and children of mothers with a lower educational level demonstrated a significantly stronger relationship between urine cotinine levels and the incidence of airway complications. The authors suggest that the former relationship is well known and has been ascribed to the greater ratio of airways to lung size or greater cholinergic irritability. A lower education level could also reflect a more stressful, crowded home environment.

Skolnick et al conclude that passive exposure to cigarette smoke should be regarded as a risk factor in children undergoing general anesthesia, and exhort anesthesiologists to educate the parents of children scheduled for surgery as well as the general public about the risks of exposure to environmental tobacco smoke.

The paper is accompanied by an editorial penned by no less a luminary than C. Everett Koop, M.D., Surgeon-General of the United States for much of the 1980s, and a tireless advocate for controls on smoking, active or passive.

Dr Koop reminds us that the prevalence of smoking is no longer on the decline, and cites the following statistics: (1) about 6,000 American teenagers try their first cigarette each day, (2) half of these will become regular smokers, (3) three quarters of these will be unable to quit even if they wish to, and (4) about one third of these will die an untimely death related to diseases attributable to tobacco smoking. He compliments the authors on the use of urinary cotinine levels as an objective marker of passive smoking, pointing out that the finding of elevated cotinine levels in flight attendants ultimately led to the federal ban on in-flight smoking.

Dr Koop also emphasizes the importance of educating parents and children about the hazards of environmental tobacco smoke, pointing out that it is responsible for as many as 50,000 deaths per year in nonsmokers. Such education, he suggests, could be triggered by an anesthesiologist reporting an adverse airway event to a child's surgeon and pediatrician.

Dr Koop concludes his editorial, not unexpectedly, on a controversial note - suggesting that "smoking in households where there are children may well become the next issue in child abuse". Whether or not one agrees with this prediction, the study by Skolnick et al impressively demonstrates the impact that exposure of children to their parents' second-hand smoke can have upon airway conditions during general anesthesia. It also suggests that as anesthesiologists we may have an important role to play in public health, as well as in the in the health of our individual patients.

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ABSTRACT