Comparison of eye protection methods for corneal abrasion during general anesthesia

BACKGROUND: Corneal abrasion is one of the most common ophthalmic complications that occurs after general anesthesia. Although they can occur by direct contact with surgical drapes or masks, most occur as a result of the drying of the cornea exposed during general anesthesia due to a reduced amount of tear secretions, the loss of light reflex, or the loss of recognition of pain during the procedure. Thus, to prevent corneal abrasions during general anesthesia, proper eye protection is required. METHODS: Seventy-two patients (144 eyes) were divided into four groups as follows: 1) control group: careful manual eye closure; 2) adhesive tape group: a bandage attached over the eyelid; 3) ointment group: eye ointment placed into the eye followed by eye closure; and 4) ointment and tape group: eye ointment placed into the eye followed by a bandage attached over the eyelid, with the patient subjected to both methods for each eye. The National Eye Institute (NEI) scale, conjunctiva hyperemia scale, tear break-up time, and Schmer test were conducted before and after operation. RESULTS: No statistically significant difference was noted between groups regarding the NEI scale, conjunctiva hyperemia scale, tear break-up time, or Schirmer test. CONCLUSIONS: To prevent corneal abrasions in normal patients undergoing general anesthesia, eye taping, eye ointment application, or taping after eye ointment application will not significantly reduce the degree of corneal epithelial damage compared to manual eye closure.

Temporal linear mode complexity as a surrogate measure of the anesthetic drug effects during sevoflurane anesthesia / 대한마취과학회지

BACKGROUND: The aims of this study were to compare the stability, correlation with end-tidal sevoflurane, and area below the effect (AUCeffect) vs. time curves of temporal linear mode complexity (TLMC) and approximate entropy (ApEn) during sevoflurane anesthesia. Another study goal was to characterize the time course of the effects of sevoflurane. METHODS: Electroencephalogram (EEG) parame1ter stability was evaluated using the coefficients of variation (CV) of the median baseline (E0), maximal (Emax), and individual median E0 - Emax values. Correlations between sevoflurane concentration and EEG parameters were tested. AUCeffect vs. time curves of TLMC and ApEn were calculated to quantitate any decrease in central nervous system activities. A sigmoid Emax model was used for pharmacodynamic modeling. RESULTS: TLMC and ApEn demonstrated CVs of 8.36 and 7.35 (for E0) and 19.61 and 13.45 (Emax), respectively. The CVs of the individual median E0 - Emax values were 65.16 for TLMC and 59.97 for ApEn. The Spearman correlation coefficient was -0.3103 for TLMC and -0.3410 for ApEn (P < 0.001 for both parameters). The median AUCeffect value was 338.9 for TLMC and 246.5 for ApEn (P = 0.457). The final pharmacodynamic parameters estimated by sigmoid Emax models were described as follows; E0: 0.614, 0.617, Emax: 0.334, 0.287, Ce50: 5.48, 5.07 vol%, gamma: 1.88, 2.01, ke0: 0.306, 0.236 min (TLMC, ApEn). CONCLUSIONS: TLMC is comparable to ApEn according to the univariate EEG descriptors of the effects of sevoflurane. A sigmoid Emax model well described the pharmacodynamics of sevoflurane for TLMC and ApEn.

Is the Spinous Process of T7 Usually at the Same Level as the Inferior Tips of the Scapulae?

OBJECTIVE: Appropriate placement of thoracic epidural catheter provides an adequate postoperative analgesia in chest and upper abdominal surgery. Usually, when thoracic epidural puncture is performed, both scapular lower tips and the thoracic (T)7 spinous process is assumed to be at the same horizontal level. The aim of this study is to identify the thoracic epidural puncture in the sitting position, with the neck flexed and arms crossed, may change the relationship between the thoracic vertebrae and the scapular lower tips. METHODS: One hundred patients with postoperative patient controlled epidural analgesia using thoracic epidural catheters were enrolled. It is presumed that the both scapular lower tips and T7 spinous process is at the equal level when performing thoracic epidural puncture. The actual insertion level of the Tuohy needle was examined by radiography when the patient was in the sitting position. RESULTS: Out of 100 patients, there were 62% that were in the same level as the scapular lower tips and T7 spinous process. However, 1% of the patients leveled at T4, 1% at T5, 25% at T6, 18% at T8, and 1% at T9. CONCLUSION: When performing the thoracic epidural puncture under the sitting position, the relationship of the T7 and the scapular lower tips may change. The change of position of scapular lower tips varied among T6.82+/-0.70. Therefore, to be precise, it is advised to utilize C-arm guide when epidural puncture is carried out.