Children at high risk for perioperative respiratory adverse events could be systematically identified at the preanesthetic assessment, and the information gained there could be used to optimize anesthetic care. They might also benefit from specifically targeted anesthesia management.

These findings come from a study that appears in the September 4 issue of the Lancet, which is focused on asthma and respiratory diseases and was published to coincide with the European Respiratory Society 2010 Annual Congress. Britta S. von Ungern-Sternberg, MD, from the Princess Margaret Hospital for Children in Subiaco, Australia, led the large prospective cohort study designed to identify associations between family history, anesthesia management, and occurrence of perioperative respiratory adverse events.

“Children at high risk for perioperative respiratory adverse events might benefit from anesthesia management, including a specialist pediatric anesthetist, intravenous induction and maintenance with propofol, and avoidance of tracheal tube for airway management when possible,” according to the researchers.

Dr. von Ungern-Sternberg added that “the incidence of upper respiratory tract infection in children presenting for anesthesia is high, and the prevalence of asthma is increasing in the pediatric population. Thus, anesthetists have to manage increasing numbers of children at high risk of perioperative respiratory adverse events in everyday clinical practice.”

Risk factors found to be associated with perioperative respiratory complications include a recent cold, wheezing during exercise, wheezing more than 3 times in the previous 12 months, nocturnal dry cough, eczema, and a family history of asthma, rhinitis, eczema, or exposure to tobacco smoke. The researchers found that these risk factors are easily identified by a risk assessment questionnaire that can be used in everyday clinical practice to optimize anesthesia care for every child.

The investigators analyzed 9297 such questionnaires. Risk factors associated with an increased risk for anesthesia-related complications were bronchospasm (relative risk [RR] 8.46; 95% confidence interval [CI], 6.18 - 11.59; P < .0001), laryngospasm (RR, 4.13; 95% CI, 3.37 - 5.08; P < .0001), and perioperative cough, desaturation, or airway obstruction (RR, 3.05; 95% CI, 2.76 - 3.37; P < .0001).

Of note, the study confirmed previous findings suggesting that current or recent upper respiratory tract infection increased the risk for perioperative respiratory adverse events. If symptoms were present at the time of surgery, RR was 2.05 (95% CI, 1.82 - 2.31; P < .0001); if symptoms were present less than 2 weeks before the procedure, RR was 2.34 (95% CI, 2.07 - 2.66; P < .0001).

“This study provides evidence that the high risk for perioperative respiratory adverse events is limited to the first 2 weeks after an upper respiratory tract infection, and thus rescheduling a patient 2 to 3 weeks after upper respiratory tract infection would be a safe approach,” the authors explain.

The effects of smoking habits of different family members on the risk for respiratory adverse events were shown for the first time in this study. The risk to the children was higher when the mother or both parents smoked than when only the father smoked. “These findings might be related to the difference in exposure to tobacco smoke from the primary caregiver,” they write.

Eczema, rhinitis, or asthma in at least 2 family members increased the risk for potentially life threatening complications (laryngospasm and bronchospasm) by nearly 3 times, according to the authors. Risk was lower with intravenous induction than with inhalational induction of anesthesia.

The investigators found that children at increased risk were best managed by an experienced pediatric anesthetist. “This study confirms the increased risk for perioperative respiratory adverse events when a patient has been cared for by a registrar [resident], and underlines the further increased risk when the registrar failed to secure the airway,” write Dr. von Ungern-Sternberg and colleagues.

Dr. von Ungern-Sternberg told Medscape Medical News that “a third of all perioperative cardiac arrests and more than three quarters of all critical incidents in pediatric anesthesia are caused by respiratory adverse events. In this study, we aimed to identify associations between the child’s history, family history, anesthesia management, and occurrence of respiratory adverse events. This allowed us to pinpoint specific risk factors for respiratory complications, as well as some indications for prevention strategies regarding anesthesia management.”

In this study, a positive respiratory history was more accurate at predicting the occurrence of respiratory adverse events than the American Society of Anesthesiologists (ASA) physical status system that is currently used to assess the likelihood of complications in children during anesthesia, Dr. von Ungern-Sternberg said. “The ASA physical status is a 6-category classification system that . . . is used to indicate the patient’s overall physical health preoperatively and might be used to scale the overall risk, although it has its limitations in children, since age is not taken into account in the calculation. Our study, on the contrary, focused only on the occurrence of respiratory complications. A positive respiratory history or other risk factors identified in our study can therefore help the anesthetist to scale the risk for the individual patient more accurately [because] it covers different aspects than the ASA classification.”

It would be beneficial if all children were screened for the presence or absence of risk factors for respiratory adverse events in the future, to identify the children at a particularly high risk preoperatively and to allow them to benefit from specifically targeted anesthesia management,” she noted.

“Children who have been identified to be at a particularly high risk for respiratory complications can benefit from a preoperative optimization of lung function by the primary care physician, if indicated and time allows, and targeted anesthesia management, which should include a specialist pediatric anesthetist, intravenous induction of anesthesia, maintenance of anesthesia with propofol, and avoidance of invasive airway management, if possible,” Dr. von Ungern-Sternberg advised.

In response, Mark A. Singleton, MD, adjunct clinical professor at Stanford University Medical School in California, and chair of the Committee on Pediatric Anesthesia at the ASA, told Medscape Medical News that the study reinforces widely accepted and fundamental pediatric anesthesia concepts and practices.

“A child with a history of respiratory problems — whether a recent upper respiratory infection, asthma, or other problems — is at an increased risk for respiratory complications during anesthesia,” Dr. Singleton said. “Additionally, research and practice demonstrates that patient outcomes improve if a physician anesthesiologist experienced in the care of infants and children administers and monitors the anesthesia.”

“ASA physical status categories are important for broad categorization of patient risk, but do not impart the thorough level of information that a complete preanesthetic evaluation reveals, which is necessary for proper preparation and the safest possible experience,” he emphasized.

In a commentary that accompanies the study, Jerrold Lerman, MD, from the Women’s and Children’s Hospital of Buffalo, New York, writes that he welcomes the study. He notes that it furthers understanding of perioperative respiratory adverse events in a cross-section of children undergoing surgery, although he adds that the reproducibility of several findings requires more research.

The study’s “external validity might be challenged and the reproducibility of several findings requires further research,” Dr. Lerman notes. “Randomized trials are required to evaluate and validate the contributions of some subpopulations and management strategies to the frequency of perioperative respiratory adverse events.”

Funding for this study came from the Department of Anaesthesia at the Princess Margaret Hospital for Children, the Swiss Foundation for Grants in Biology and Medicine, and the Voluntary Academic Society Basel. Dr. Ungern-Sternberg, Dr. Singleton, and Dr. Lerman have disclosed no relevant financial relationships.

Lancet. 2010;376:745-746, 773-783.

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