Propionic acidemia in a four-month-old male: a case study and anesthetic implications.

Propionic acidemia is a rare genetic disease associated with significant medical problems. When patients with this disease present for surgery, their anesthetic must be tailored to meet their special needs. This case report provides information regarding propionic acidemia and its anesthetic management.

Apneic anesthesia with intermittent ventilation for microsurgery of the upper airway.

Apneic anesthesia with intermittent ventilation (AAIV) has been used in 250 procedures on the larynx and trachea at Indiana University Medical Center since October 1989. Initially employed for laryngeal papilloma removal in children, this anesthetic technique is now used for other procedures and in adult patients. The advantages of AAIV include improved visualization of the airway, absence of combustible material, and lack of vocal cord motion during surgery. No significant complications have occurred with AAIV. The high degree of safety for this anesthetic technique relates largely to the constant monitoring of oxygen saturation using pulse oximetry and the periodic measurement of end-tidal carbon dioxide (CO2) levels. Contraindications to AAIV are age less than 2 years, significant cardiopulmonary disease, and any hypermetabolic state. Relevant pulmonary physiology includes the unique aspects of oxygen and CO2 metabolism in children.

Anesthesia for the newborn and ex-preterm infant.

This article addresses the pertinent aspects of neonatal physiology and pharmacology, general considerations in the anesthetic care of surgical neonates, management details of selected neonatal surgical lesions, and anesthetic considerations for the ex-preterm infant.

Chest radiograph changes after cardiopulmonary bypass in children.

To determine the spectrum of pediatric chest radiograph changes after cardiopulmonary bypass, 98 children (mean age = 5.9 yr, range 4 wk-16 yr) were studied for 3 days postoperatively. Daily A-P radiographs were evaluated for atelectasis, cardiomegaly, pleural effusions, diaphragmatic elevation, mediastinal widening, and pulmonary infiltrates. The overall incidence of atelectasis was 82%, with left lower lobe atelectasis the most common (64%). Right upper lobe atelectasis occurred in 35% of patients, far more common than in the adult. Radiographic changes were then compared with independent variables including patient weight, age, duration of bypass, and fluid balance by multiple linear regression. Pleural effusion correlated with patient weight and duration of bypass. Diaphragmatic elevation correlated with patient weight. Cardiomegaly correlated with patient age. Net fluid balance was a poor predictor of postoperative chest radiograph changes. We conclude that radiographic changes are common after cardiopulmonary bypass in children, that the overall incidence is not markedly different from adults, and that right upper lobe atelectasis occurs more frequently in children.

Site of recruitment in the pulmonary microcirculation.

Increasing the total surface area of the pulmonary blood-gas interface by capillary recruitment is an important factor in maintaining adequate oxygenation when metabolic demands increase. Capillaries are known to be recruited during conditions that raise pulmonary blood flow and pressure. To determine whether pulmonary arterioles and venules are part of the recruitment process, we made in vivo microscopic observations of the subpleural microcirculation (all vessels less than 100 microns) in the upper lung where blood flow is low (zone 2). To evoke recruitment, pulmonary arterial pressure was elevated either by an intravascular fluid load or by airway hypoxia. Of 209 arteriolar segments compared during low and high pulmonary arterial pressures, none recruited or derecruited. Elevated arterial pressure, however, did increase the number of perfused capillary segments by 96% with hypoxia and 165% with fluid load. Recruitment was essentially absent in venules (4 cases of recruitment in 289 segments as pressure was raised). These data support the concept that recruitment in the pulmonary circulation is exclusively a capillary event.