State-Dependent Laryngomalacia in Sleeping Children

Laryngomalacia is a common congenital laryngeal abnormality. Despite its being widely discussed in the literature, the pathophysiology is not clearly understood. Both anatomic and neuromuscular theories have been suggested to explain laryngomalacia. We report 4 cases of laryngomalacia in which the presenting signs occurred during sleep. Awake flexible nasopharyngolaryngoscopy failed to demonstrate supraglottic structure collapse. Only while the patients were breathing spontaneously under general anesthesia was laryngomalacia noted. A proposed algorithm for diagnosis and treatment is included. These 4 cases of state-dependent laryngomalacia support a neuromuscular cause for laryngomalacia.

Pediatric sedation: can it be safely performed by non-anesthesiologists?

PURPOSE OF REVIEW

The purpose of the present review is to provide the reader with a synopsis of the recent literature on sedation of children by non-anesthesiologists.

RECENT FINDINGS

Health care centers are experiencing an increasing demand for sedation of pediatric patients. Whether provided by physician anesthesiologists, nurse anesthetists, or appropriately credentialed non-anesthesia clinicians, this increase is a reflection of new advances in the area of diagnostic imaging, better pharmacologic agents, and a heightened awareness of the psychologic needs of children. By definition anesthesiologists are the experts when it comes to providing sedation to patients. For pediatric patients, pediatric anesthesiologists provide the most appropriate specialization. However, because of insufficient manpower, anesthesiologists cannot adequately meet the increasing workload of providing sedation for each child in need.

SUMMARY

In some circumstances the incidence of adverse events when sedation is provided by non-anesthesiologist can be high. Predicators of adverse outcome have been identified. Given strict adherence to sedation guidelines and appropriate credentialing of the sedation provider, non-anesthesiologists can safely provide sedation for children.

Postoperative sore throat in children and the laryngeal mask airway

Postoperative sore throat is a minor complaint after general anaesthesia of multifactorial aetiology. The purpose of this study was to compare the effect of the laryngeal mask airway (LMA) and endotracheal tube (ETT) on postoperative sore throat in children. We hypothesized that the incidence of sore throat would be less after the use of the LMA. This was a randomized, single-blind study of 112 patients of age 3 to 12 yr undergoing minor peripheral surgery. The groups were similar, except that airway maintenance was either with an LMA or ETT. After induction of anaesthesia with O2, N2O and halothane, an LMA or ETT was inserted. Anaesthesia was maintained with O2, N2O and halothane. At the end of surgery, the ETT was removed in the operating room before airway reflexes had returned. The LMA was removed after the patient's airway reflexes had returned in the recovery room. On the first postoperative day, the parents were contacted and asked whether or not their child had had a sore throat. If a sore throat had been present, the parents rated the discomfort as mild, moderate or severe. The groups were similar with respect to age, weight, sex and duration of procedure. The overall incidence of sore throat was 9%. The difference between the groups (LMA 13% vs ETT 5%) was not statistically significant. All of the reported sore throats were rated as mild. In conclusion, postoperative sore throats after minor paediatric surgery is uncommon. If it does occur, it is mild and the incidence is unaffected by the choice of an LMA or ETT.

Isoflurane, compared to halothane or enflurane, causes increased lactate production but no transmural coronary steal during myocardial ischemia in swine

We compared the effects of isoflurane, enflurane, and halothane on myocardial blood flow, function, and metabolism in normally perfused and ischemic regions of the swine heart. A model of single vessel incomplete occlusion was used so that the capacity of these anesthetics to cause transmural coronary steal could be tested. After median sternotomy, the left anterior descending coronary artery (LAD) was cannulated and autoperfused from the carotid artery. Systolic segment shortening was measured in the regions of the heart perfused by the LAD and left circumflex arteries. Regional myocardial blood flow was measured with radioactive microspheres. Blood was obtained from the anterior cardiac vein for measurement of lactate. Measurements were made during imposition of a stenosis on the perfusion circuit sufficient to decrease resting flow by 25%. The same stenosis was imposed during three treatment periods in a randomized and balanced cross-over design. In one group of 12 swine, treatments were two doses of intracoronary adenosine and a control period. A second group of 12 were given 1.5% isoflurane, 2.18% enflurane, and 0.98% halothane. Heart rate, mean aortic pressure, and left atrial pressure were matched during the three treatments in each animal. Adenosine caused transmural steal resulting in diminished systolic segment shortening in the ischemic LAD region. During isoflurane, compared to halothane, the first derivative of left ventricular pressure with respect to time was greater by 28%, and systolic segment shortening in the normal left circumflex artery and ischemic LAD regions was greater by 27% and 31%, respectively. Subepicardial flow in the ischemic region was greater with isoflurane but subendocardial flow was unchanged. Lactate production during isoflurane was 52% and 76% greater than during halothane and enflurane, respectively. Our results indicate that isoflurane is not a sufficiently potent arteriolar vasodilator in swine to cause transmural steal. Although myocardial performance was superior with isoflurane in both ischemic and normally perfused regions, lactate production also increased, suggesting worsened ischemic metabolism. It is likely that the myocardial oxygen supply/demand ratio worsened with isoflurane because it caused less myocardial depression than the other anesthetics.