Bronchial spasm during general anaesthesia

Anesthesia considerations for lung volume reduction surgery

Patient selection is of crucial importance for outcome after lung volume reduction surgery. The anesthesiologist should be involved actively in patient selection, because he or she is in charge of the treatment during the critical perioperative period. Patient history and status and results from chest radiographs, high-resolution CT scans, and catheterization of the right heart should be taken carefully into account in the patient selection process. Promising new results involving functional parameters may predict outcome objectively after lung volume reduction surgery in the future. Careful selection and preoperative preparation of patients also are important to avoid complications and keep the success rate high. The anesthesiologist's understanding of the principles involved is important for the successful conduct of lung volume reduction surgery. It is unclear if lung volume reduction surgery is superior to conventional therapy in the long run because the decline in lung function is progressive after the procedure. A multicenter trial comparing patients undergoing lung volume reduction surgery with patients with emphysema who are treated conventionally hopefully will clarify this important question in the future.

Effects of high thoracic epidural anaesthesia on the peripheral airway reactivity in dogs

BACKGROUND

It has been speculated that epidural anaesthesia may induce bronchoconstriction via the mechanism of a sympathetic blockade. However, this hypothesis has not been confirmed by any experimental evidence. Therefore, we investigated the effects of high thoracic epidural anaesthesia with neural sympathetic blockade on basal airway resistance and airway reactivity in response to bronchoconstrictive stimuli in a canine periphery lung model.

METHODS

Acetylcholine (Ach, 8 microg kg[-1] i.v.) or histamine (His, 3 microg kg[-1] i.v.) was administered to 7 anaesthetized mongrel dogs before and after thoracic epidural anaesthesia. Successful neuronal sympathectomy was confirmed by nitroglycerin test. The changes of peripheral airway resistance (Rp), haemodynamics, cardiac output (CO), and the recovery time for Rp from peak returning to baseline in each challenge were studied.

RESULTS

Thoracic epidural anaesthesia altered neither the baseline Rp nor the peak Rp evoked by Ach or His. However, the recovery time of the Rp was prolonged significantly after epidural anaesthesia (P<0.01) and correlated inversely with the CO in response to Ach or His challenge (Ach, r=0.542; His, r=0.651).

CONCLUSIONS

Our results suggest that epidural anaesthesia with neural sympathetic blockade has no influence on the basal peripheral airway resistance; however, it prolongs the airway reactivity to Ach or His challenge, probably by the mechanism of reducing CO.

Perioperative management for childhood asthma

BACKGROUND

Children with asthma have been reported to be at increased risk for intraoperative bronchospasm. Current medical literature focuses on this problem in adult patients. This is a report of our experience in children.

OBJECTIVE

The purpose of this study was to discern whether children with reactive airways disease (asthma) actually had a high likelihood of perioperative bronchospasm as the medical literature suggests.

METHODS

A retrospective chart review of 386 asthmatic children and 51 with bronchopulmonary dysplasia seen perioperatively between 1987 and 1992 was instituted. Children with asthma were classified as mild, moderate or severe based on the number of hospitalizations, emergency room visits, intensive care unit admissions and medications at the time of evaluation. Patients with bronchopulmonary dysplasia were included in a separate category. Individualized asthma management was recommended for all patients in preparation for surgery. Blood gases, chest radiographs and pulmonary function studies were not routinely ordered.

RESULTS

Only 3 of 437 children in a five-year period (0.13%) had intraoperative bronchospasm, easily controlled with the use of beta-2 agonists.

CONCLUSIONS

This study demonstrates that asthmatic children appropriately prepared for surgery do not appear to have an increased risk for adverse outcome. The children treated with more than inhaled beta-2 agonists were those who had more severe asthma, recent viral infection, recent exacerbation of asthma, or recent hospitalization for asthma.

Bronchospasm during anaesthesia. A computer-aided incidence study of 136,929 patients

With the aid of a computer-based anaesthetic record-keeping system, anaesthetics complicated by bronchospasm during anaesthesia at the Karolinska Hospital were retrieved. The incidence of bronchospasm was calculated in groups characterized by various variables. In total, 246 cases of bronchospasm in 156,064 anaesthetics were retrieved. This corresponds to one case in 634 anaesthetics or 1.7 per 1000 patients. High incidence figures were seen in the age group 0-9 years (4.0/1000) when the patients showed a respiratory infection (41.1/1000), a pathological preoperative ECG (24.3/1000), an obstructive lung disease (21.9/1000), were classified as belonging to ASA class III (23.8/1000), if a tracheal intubation was performed (9.1/1000) or a rectal anaesthesia (35.7/1000) was given. In the age group 50-69 years (1.8/1000), high incidence figures were seen when there was an airway obstruction (8.8/1000), an obstructive lung disease (7.7/1000), a previous myocardial infarction (5.4/1000), a bronchoscopy (7.6/1000) or a mediastinoscopy (7.8/1000) was performed. Most of the cases had no history of allergy or asthma recorded in the anaesthetic form. In this series the triggering factor more often seemed to be of mechanical origin. There were no intraoperative deaths.

Severe histamine mediated reactions to intravenous drugs used in anaesthesia

Severe histamine mediated reactions to intravenous drugs used in anaesthesia may occur as a result of anaphylactic and anaphylactoid reactions. The incidence is rare, but appears to be increasing. The difficulties in diagnosing such reactions and in determining the drug responsible and how these difficulties have led to confusion in the literature are discussed. Six cases of severe histamine mediated reactions are presented and detailed analyses of the drugs in these and other reported reactions is made showing varied clinical patterns with different drugs. The prevention, treatment, and follow-up of severe histamine mediated reactions are considered.