Background and Goal of Study:Variations in optic nerve sheath diameter (ONSD) measured by ultrasonography may be an indirect marker of intracranial pressure (ICP) alterations, especially for ICP increases. The primary aim of this study is to observe the effect of pneumoperitoneum on ONSD measured by ultrasonography, where the secondary goal is to investigate the changes of ONSD caused by perioperative body position in paediatric patients undergoing laparoscopic appendectomy.

Materials and Methods:This study is compromised of the observation over 28 patients (5-12 years in age). After premedication with midazolam 0.5mgkg-1po, induction was achieved with propofol 3mgkg-1, rocuronium 0.6mgkg-1, remifentanil 0.3-0.5mcgkg-1 following the routine ASA monitoring. Anaesthesia maintenance was provided by 2-3% sevoflurane in a mixture of 40%O2-60%N2O. Intraabdominal pressure was maintained as 12mmHg during pneumoperitoneum. Both left and right ONSD measurements were performed as a transverse diameter of the sheath on 3mm far from the exit of the optic nerve with the linear probe of 7-12 MHz frequency. The values were recorded as follows:3 min after induction (t0), 5 min after insufflation (t1), 5 min after trendelenburg and 15 degrees to the left tilted position (t2), 15 min after insufflation (t3), 30 min after insufflation (t4) and 5 min after desufflation (t5). For statistical analysis, one way ANOVA, Paired t-test and Wilcoxon tests were applied.

Results and Discussion:ONSD was determined as t0:5,12±0,49 mm, t1:5,41±0,49 mm, t2:5,63±0,58 mm (%95CI t0 and t1 for: p<0.001, t1 and t2 for p=0.001) on the right and t0:5,12±0,46 mm, t1:5,42±0,49 mm, t2:5,58±0,46 mm (%95CI t0 and t1 for p<0.001, t1 and t2 for p=0.003) on the left side. There was no difference between t0 and t5 (t0: 5,12±0,49 mm, t5:5,28±0,53 mm %95CI p=0.27) on the right side. However, there was a statistically significant difference between t0 and t5 (t0:5,12±0,46 mm, t5:5,30±0,48 mm %95 CI p=0.019) on the left side. There are numerous studies showing that pneumoperitoneum increases the ONSD. However, the effect of the body position on ONSD is controversial. The present study revealed that pneumoperitoneum along with body position might affect ICP and accordingly ONSD.

Conclusion(s):The ultrasonographic measurement of ONSD might be an alternative method of monitoring the degree of ICP changes during laparoscopic procedures in paediatric patients.

02 / The effect of pneumoperitoneum on optic nerve sheath diameter in paediatric patients undergoing laparoscopic appendectomy operation