Following strabismus surgery, patients frequently develop variable degrees of postoperative nausea and vomiting (PONV). These symptoms cause discomfort and result in serious complications such as ...intramuscular bleeding and subconjunctival hemorrhage. In children long lasting PONV can lead to and electrolyte imbalance and dehydration. A prolonged course of recovery is the consequence. For the hospital, PONV can also involve negative economic impacts because of a damaged public reputation of the institution. There is still an ongoing debate on wether prophylaxis of PONV is necessary and how the prophylaxis of PONV should be performed. On one hand, there are proponents of a liberal prophylaxis. These intend to treat almost all patients regardless of their individual risk for PONV. On the other hand, opponents point out that every medication has to be indicated individually. In their view, risk scores should be the base of a risk-adapted approach.
The aim of the study was to reduce the frequency of PONV by using an anesthetic technique adapted to the individual risk for PONV. Until now, all trials studying the efficiency of a score-based antiemetic prophylaxis were performed on adult patients. In this study, a risk-adapted approach was evaluated on children for the first time.
In 92 patients, the incidence of PONV was analyzed after strabismus surgery. Before surgery we evaluated the risk factors for PONV according to the POVOC score in children (n = 45, 49 %) and the Apfel's score in adults (n = 47, 51 %). Patients with 0-2 risk factors received a balanced anesthesia (n = 47, 51 %). Those with 3-4 risk factors were operated in total IV anesthesia (TIVA) with propofol (n = 45, 49 %). In addition, as an antiemetic prophylaxis, 0.15 mg/kg dexamethason and 0.1 mg/kg ondansetron were applied in the latter patients. we documented the symptoms and severity of PONV 2, 6 and 24 h after surgery by means of a standardized questionnaire for PONV (Wengritzky-Score).
The incidence of PONV was 17 % (n = 16) in all of the patients. The incidence in low-risk patients receiving a BA without prophylaxis were 21 % in adults and 38 % in children. Of the patients at high risk for PONV receiving the multimodal antiemetic approach 8 % (adults) and 9 % (children) suffered from PONV. The combination of TIVA and antiemetics could reduce the incidence of PONV compared to the predicted values in a clinically relevant manner (OR = 0.26, KI: 0.76-0.87).
The overall incidence could be reduced to a level below 20 %. Particularly in patients with a high risk of PONV, TIVA could clearly reduce the incidence. However, the incidence in patients with 2 risk factors is still high (30-39 %). Therefore, it is important to reconsider the effort involved with risk screening and individually adapting anesthesia. Risk stratification means a pre- and perioperative effort. Therefore, we advocate a more liberal approach for PONV prophylaxis.
There has been long-standing clinical and electrophysiological evidence that in patients with albinism the visual pathways cross atypically: most fibres from one eye cross to the contralateral visual ...cortex.
to determine whether the size and configuration of the optic chiasm in human albinos is different from normally pigmented controls.
17 patients (11 female, mean age 35.8 years) with oculocutaneous albinism underwent a standardised graded morphological and functional evaluation. Magnetic resonance images were reformatted to the region of the optic chiasm and analysed using observer-independent morphometry. In addition, fMRI of the visual cortex was performed during VEP analysis (1.5 Tesla Siemens Vision). Morphological and fMRT results were compared to an age-correlated group of n = 16 normally pigmented healthy volunteers with normal visual acuity and stereopsis.
65 % of the patients (n = 10) showed signs of dysplasia of the optic nerve head. Statistical morphometry showed distinct differences in chiasmal morphology between albinos and normally pigmented probands (smaller optic nerves, different angles of optical entry into the chiasm and of the beginning of the Tractus optici leaving the chiasm, overall chiasmal width and height).
Optic nerve head anomalies are frequent in albinism and influence visual outcome. Size and configuration of the optic chiasm in human albinos is distinctly different from normally pigmented control persons and reflects the atypical crossing of optic fibres.
