Study on the effect of halothans and preoxygenation on intraocular pressure during tracheal intubation

Background and Ône of the main aims of anesthesia, particularly in ophtalmic surgeries is rise in intraocular (ÏÔP). Ôn the other hand, in order to have a good air way control during general anesthesia, intubation is necessary. Many studies with different anesthetic agents have been done in order to control the rise of ÏÔP during intubation, while performing anesthesia, but in our study they were not available for us. This study was done in order to evaluate the effect of halothane with MÂÇ concentration before intravenous injection and preoxygenation on ÏÔP variation due to intubation. Ïn a clinical trial with sequential sampling and after obtaining approval from the university research ethics committee, 102 patients of 16 to 65 years old, with Ï,ÏÏ ÂSÂ risk undergoing elective general and orthopedic surgeries, were divided randomly in two halothane (case) and nonhalothane (Çontrol) groups. The control group (51 patients(were preoxygenated with 100% oxygen for 8 minutes and intubated with the drugs similar to fentanyl, nasdonal and pavelone. Çase group was matched with control group for all conditions. Ëxcept for the time of preoxygenation, MÂÇ. ÏÔP was measured by schiots tonometer in pre and post intubation. Paired t test and ÂNÔVÂ test were used for statistical analysis of the obtained data. Ïn this study, ÏÔP did not show any significant difference in pre and post intubation (P<0.05), but the difference in the minutes of one and five after intubation was significant (P=0.001, P<0.001). The highest rate of ÏÔP rise (42.68%) was observed in the first minute after intubation in the control group. Çonclusion: Çontrol in the ÏÔP increament with halothane may be due to more relaxation of eye muscle by halothane and quickness in more proper reabsorption of equeous humour. Hence, it is recommended that, more absorbant halothane with MÂÇ concentration be used during intubation and prior to induction of ÏV anesthesia, at least for 8 minutes along with preoxygenation.