Sevoflurane and isoflurane reduce oxygen saturation in infants

Volatile anesthetics are generally known to exert several influences on the respiratory system, but their direct effect on oxygen saturation as measured by pulse oximetry (SpO2) in infants remains unknown. In this study, 70 infants under 2 years of age who received general anesthesia were examined to determine the effects of several volatile anesthetics and nitrous oxide on SpO2. After endotracheal intubation, the subjects were ventilated using a Jackson-Rees circuit with oxygen, nitrous oxide, and either sevoflurane, enflurane, or isoflurane adjusted to twice the adult minimum alveolar concentration (MAC) for the agents when used in combination with 67% nitrous oxide. In all cases, the end-tidal carbon dioxide tension (PetCO2) was maintained within the same range (28-35 mm Hg). Significantly lower SpO2 values (paired t test, P < .05) were observed when the subjects were ventilated with oxygen, 67% nitrous oxide, and sevoflurane or isoflurane--but not with oxygen, 67% nitrous oxide, and enflurane--than when they were administered oxygen, 50% nitrous oxide, and the original concentration of each volatile anesthetic. These results suggest that sevoflurane and isoflurane have different effects from enflurane on gas exchange systems.     

Digital chest radiography with a selenium-based flat-panel detector versus a storage phosphor system: comparison of soft-copy images

OBJECTIVE. We compared the soft-copy images produced by a digital chest radiography system that uses a flat-panel X-ray detector based on amorphous selenium with images produced by a storage phosphor radiography system for the visualization of anatomic regions of the chest. MATERIALS AND METHODS. Two chest radiologists and two residents analyzed 46 pairs of posteroanterior chest radiographs on high-resolution video monitors (2560 x 2048 x 8 bits). In each pair, one radiograph was obtained with a storage phosphor radiography system, and the other radiograph was obtained with a selenium-based flat-panel detector radiography system. Each pair of radiographs was obtained at the same exposure settings. The interpreter rated the visibility and radiographic quality of 11 different anatomic regions. Each pair of images was ranked on a five-point scale (1 = prefer image A, 3 = no preference, 5 = prefer image B) for preference of technique. Statistical significance of preference was determined using the Wilcoxon's signed rank test. RESULTS. The interpreters had a statistically significant preference for the selenium-based radiography system in six (unobscured lung, hilum, rib, minor fissure, heart border, and overall appearance) of 11 anatomic regions (p<0.001) and for the storage phosphor system in two regions (proximal airway and thoracic spine) (p<0.05). Chest radiologists strongly preferred selenium-based images in eight regions, and they did not prefer storage phosphor images in any region. CONCLUSION. The soft-copy images produced by the selenium-based radiography system were perceived as equal or superior to those produced by the storage phosphor system in most but not all anatomic regions.     

The "High-Riding" superior pericardial recess: CT findings

OBJECTIVE. We recently observed patients in whom the superior pericardial recess extended cephalad ("high-riding") into the right paratracheal region. In these patients, differentiation from mediastinal lymphadenopathy or mass was difficult. The purpose of this study was to assess the prevalence and CT features of the high-riding superior pericardial recess. CONCLUSION. Narrow-collimation CT with multiplanar reformations was useful for confidently diagnosing a high-riding superior pericardial recess and for distinguishing it from pathologic lesions.     

Renal and pulmonary lymphangioleiomyomatosis: a case report

Lymphangioleiomyomatosis (LAM) is a rare disease that most commonly involves the lung. However, extrapulmonary lymphangioleiomyomatosis rarely occurs with or without subsequent involvement of the lung. We report a case of incidentally found renal and pulmonary lymphangioleiomyomatosis in a patient who had no stigmata of tuberous sclerosis.     

Graft replacement of transverse aortic arch using the arch vessels first technique

In surgical treatment of aortic arch aneurysm or aortic dissection, we have been employing retrograde cerebral perfusion (RCP). In the present study, we have developed "arch vessels first technique" to shorten perfusion time and achieved an excellent clinical outcome. The surgical procedure "arch vessels first technique" is outlined as follows. RCP is initiated following circulatory arrest, while a woven dacron graft (12 mm in diameter, the dacron graft must be prepared in advance) with two side arms (12 mm in diameter, i.e., with the same diameter) is anastomosed left subclavian artery, left common carotid artery and right brachiocepharic artery in a sequential manner. Then, brain circulation is initiated via one end of the dacron graft. Subsequently, in patients with aortic dissection, a 26 mm woven dacron tubular prosthesis is inserted, using an elephant trunk procedure, to perform "distal anastomose". A partial clamp is applied to the 12 mm woven dacron graft mentioned above, while this 26 mm graft is anastmosed to the 12 mm woven dacron graft side to side, thus reinitiating systemic circulation. While rewarming, the 26 mm woven dacron tubular prosthesis is proximal anastomosed. Mean RCP time was 79.4 minutes, using the conventional procedure "aortic arch distal anastomose", whereas the RCP time was shortened by this procedure "arch vessels first technique", as evidenced by mean RCP time of 57 minutes for patient with aortic dissection and of 39 minutes for patient with saccular aneurysm.     

Surgical treatment of intractable epilepsy accompanying cortical dysplasia

OBJECT: Surgical treatment of cortical dysplasia (CD) together with intractable seizures is challenging because both visualization and localization of the lesion are difficult, correlation with seizure foci requires comprehensive study, and the surgical outcomes reported thus far are unsatisfactory. The authors report their experience in the surgical treatment of CD classified according to a surgical point of view. METHODS: The definition of CD used in this study was a dysplastic lesion visible on magnetic resonance (MR) images or a lesion that, although not visible on MR images, was diagnosed as moderate-to-severe dysplasia by using pathological analysis. During the last 4.5 years, the authors treated 36 patients with intractable epilepsy accompanied by CD. They divided the 36 cases of CD into four characteristic groups: Group A, diffuse bilateral hemispheric dysplasia; Group B, diffuse lobar dysplasia; Group C, focal dysplasia; and Group D, a moderate to severe degree of CD with a normal appearance on MR images. All but one patient in Group C were monitored in the epilepsy monitoring unit by using subdural electrodes for seizure localization and functional mapping. The incidence of CD among a cohort of 291 patients who had undergone epilepsy surgery at the authors' center during the study period was 12.4%. The mean age of the 36 patients was 21.3 years and the mean age at seizure onset was 8.5 years. The mean follow-up period was 26 months. Twenty-six patients (72.2%) belonged to Engel Class I or II (20 and six, respectively). There were five cases in Group A, nine in Group B, nine in Group C, and 13 in Group D. Patients in Groups A and B were significantly younger at seizure onset and had significantly poorer surgical outcomes compared with patients in Groups C and D (p < 0.05). If outcome is compared on the basis of the extent of removal of CD, patients in whom CD was completely removed had significantly better outcomes than those in whom CD was only partially removed (p < 0.001). CONCLUSIONS: The authors conclude that intractable epilepsy accompanied by CD can be treated surgically using comprehensive preoperative approaches. Deliberate resective procedures aimed at complete removal of dysplastic tissue ensure excellent seizure control without permanent neurological deficit.