Determinants of Radiation Dose in Selective Ophthalmic Artery Chemosurgery for Retinoblastoma.

BACKGROUND AND PURPOSE: Retinoblastoma is the most common pediatric ocular neoplasm. Multimodality treatment approaches are commonplace, and selective ophthalmic artery chemosurgery has emerged as a safe and effective treatment in selected patients. Minimizing radiation dose in this highly radiosensitive patient cohort is critical. We explore which procedural factors affect the radiation dose in a single-center cohort of children managed in the UK National Retinoblastoma Service. MATERIALS AND METHODS: A retrospective review was performed of 177 selective ophthalmic artery chemosurgery procedures in 48 patients with retinoblastoma (2013-2017). Medical records, angiographic imaging, and radiation dosimetry data (including total fluoroscopic screening time, skin dose, and dose-area product) were reviewed. RESULTS: The mean fluoroscopic time was 13.5 ± 13 minutes, the mean dose-area product was 11.7 ± 9.7 Gy.cm2, and the mean total skin dose was 260.9 ± 211.6 mGy. One hundred sixty-three of 177 procedures (92.1%) were technically successful. In 14 (7.9%), the initial attempt was unsuccessful (successful in 13/14 re-attempts). Screening time and radiation dose were associated with drug-delivery microcatheter location and patient age; screening time was associated with treatment cycle. CONCLUSIONS: In selective ophthalmic artery chemosurgery, a microcatheter tip position in the proximal or ostial ophthalmic artery and patient age 2 years or younger were associated with reduced fluoroscopic screening time and radiation dose; treatment beyond the first cycle was associated with reduced fluoroscopic screening time.

Unilateral vs. bilateral ultrasound in the monitoring of cerebral microemboli.

We used bilateral transcranial Doppler to monitor the number of microembolic events (ME) in the left and right middle cerebral arteries of 29 patients during cardiac surgery that required extracorporeal circulation. Based on a previously published study, we hypothesized that the commonly used method of doubling unilateral ME counts to obtain an estimated bihemispheric load would result in significant errors of estimation. In our sample, estimated bihemispheric counts were inaccurate by an average of 18% (range 0--80%). Despite this large range of error, calculation of Cronbach's alpha revealed that actual error due to unreliability (4%) was small relative to the large variation in ME counts across subjects in this patient series. These findings suggest that unilateral monitoring is sufficient when the goal is to characterize a given subject's ME load within the context of the other subjects in the sample. However, when precise ME counts are required, bilateral monitoring is essential.

Cerebral microembolism diagnosed by transcranial Doppler during total knee arthroplasty: correlation with transesophageal echocardiography.

BACKGROUND: Tourniquet deflation following total knee arthroplasty (TKA) frequently results in release of emboli into the pulmonary circulation. Small emboli may gain access to the systemic circulation via a transpulmonary route or through a patent foramen ovale. This study examined the incidence of cerebral microembolism after tourniquet release by transcranial Doppler (TCD) ultrasonography and its correlation with echogenic material detected in the left atrium. METHODS: Twenty-two adult patients (9 men, 13 women) undergoing TKA were studied with simultaneous TCD ultrasonography and transesophageal echocardiography. Data were recorded after anesthesia induction and tourniquet inflation and during tourniquet deflation. Emboli counts were performed manually off-line. Echogenic material in the left atrium was qualitatively assessed and correlated with TCD data. Patients were examined postoperatively for focal neurologic deficits. RESULTS: Fifteen patients had unilateral TKA (six left, nine right) and seven had bilateral TKA. Cerebral emboli were detected in 9 of 15 patients (60%) with unilateral TKA and in 4 of 7 patients (57%) with bilateral TKA. Echogenic material was identified in the left atrium in eight patients (two through a patent foramen ovale and six from the pulmonary veins). Emboli counts were significantly higher in patients with bilateral TKA compared with those with unilateral TKA (P<0.05). Duration of tourniquet time in patients with emboli was longer only during bilateral TKA (P<0.05). All patients with echogenic material in the left atrium detected by transesophageal echocardiography had emboli as assessed by TCD ultrasonography. No focal neurologic deficits were identified. CONCLUSIONS: Cerebral microembolism occurs frequently during tourniquet release, even in the absence of a patient foramen ovale. This passage most likely occurs through the pulmonary capillaries or the opening of recruitable pulmonary vessels.

Comparison of dependent-care activities for well siblings of children with cystic fibrosis and well siblings in families without children with chronic illness.

The purpose of this study was to determine if well siblings in families with a child with cystic fibrosis receive less dependent care, as defined by Orem, than well siblings in families without children with chronic illness. Nineteen mothers of children with cystic fibrosis and a well sibling and 19 mothers of only well children completed the Dependent Care Agent Instrument. In this population, no significant differences were found in a mother's performance of dependent-care activities for well siblings of children with cystic fibrosis and well siblings in families without children with a chronic illness. The possibility of a difference in a child's and mother's perception of parenting and the use of a questionnaire to study parenting is discussed. The implication that the child's perception of dependent care received is overlooked by focusing only on the mother's perception warrants further consideration.

Continuous positive airway pressure is beneficial in treatment of smoke inhalation.

This study demonstrates that continuous positive airway pressure (CPAP) improves pulmonary function after smoke inhalation by dogs. Sixteen dogs were anesthetized with iv sodium pentobarbital. Arterial and mixed venous blood gas tensions; carboxyhemoglobin concentration (COHgb); mean systemic arterial (MAP), mean pulmonary arterial (MPAP), and pulmonary arterial wedge (WP) pressures; heart (HR) and respiratory (f) rates; cardiac output (CO); and airway pressure (Paw) were measured. Intrapulmonary physiologic shunt (Qsp/Qt) and pulmonary (PVR) and systemic (SVR) vascular resistances were calculated. The animals then breathed an aerosol of smoke and were divided randomly into 2 groups. The treatment group breathed spontaneously on 8-torr CPAP whereas the control group continued to breathe spontaneously at ambient pressure. After inhalation of smoke, Qsp/Qt, MPAP, PVR, COHgb, HR, and f rose, whereas PaO2 and MAP fell in untreated animals. When CPAP was applied, PaO2 and Qsp/Qt returned nearly to baseline values. Mean f also was significantly lower in the treated animals. We found that the early institution of CPAP improves oxygen exchange in the lungs after the inhalation of smoke.