Midazolam anaphylaxis during general anesthesia: A case report.

RATIONALE: Midazolam is known as a safe drug and is widely used as a sedative and an anesthetic adjuvant. Therefore, there is a lack of awareness that midazolam can cause anaphylaxis. Midazolam anaphylaxis is rare, and only a few cases have been reported, but such a risk is always present. In this study, we report a case of midazolam anaphylaxis by an intravenous injection, in the prone position, during general anesthesia. PATIENT CONCERNS: A 62-year-old woman was intravenously administered 1 mg midazolam during general anesthesia, and sudden severe hypotension, bronchospasm, decreased oxygen saturation, erythema, and diarrhea occurred. DIAGNOSIS: Midazolam anaphylaxis was presumptively diagnosed by clinical symptoms and was confirmed by an intradermal test after 9 weeks. INTERVENTIONS: The patient was treated with 100% oxygen, large volume of fluid, epinephrine, phenylephrine, ephedrine, dexamethasone and prednisolone, ranitidine, and flumazenil. OUTCOMES: Severe hypotension and decreased oxygen saturation were resolved within 20 minutes of the onset of anaphylaxis, and the patient was discharged after 3 days without any sequelae. LESSONS: Midazolam anaphylaxis is very rare, but it can happen always. Therefore, the possibility of anaphylaxis due to midazolam should be considered and always be prepared for treatment.

Comparison of the recovery and respiratory effects of aminophylline and doxapram following total intravenous anesthesia with propofol and remifentanil.

STUDY OBJECTIVE: To compare the effects of aminophylline and doxapram on recovery, respiration, and bispectral index (BIS) values in patients after total intravenous anesthesia (TIVA) with propofol and remifentanil. DESIGN: Prospective, randomized, blinded clinical trial. SETTING: Operating room of a university hospital. PATIENTS: 90 adult, ASA physical status 1 and 2 patients scheduled for elective laparoscopic vaginal hysterectomy. INTERVENTIONS: TIVA was performed with the induction target of remifentanil 3 ng/mL and propofol 6 µg/mL, followed by the maintenance target of remifentanil 1-3 ng/mL and propofol 3-5 µg/mL at the effect site, and with BIS scores in 40-50 range. Patients were randomized to three groups to receive intravenous (IV) aminophylline 3 mg/kg (n = 30), IV doxapram 1 mg/kg (n = 30), or normal IV saline (control; n = 30). MEASUREMENTS AND MAIN RESULTS: After administration of the study drugs, return to spontaneous ventilation differed significantly among the three groups. The times to eye opening and hand squeezing on verbal command were similar. The time to extubation was shortened in both the doxapram and aminophylline groups (P < 0.05). Tidal volumes were increased in the doxapram group at 5-14 minutes and the aminophylline group at 5-12 minutes (P < 0.05). Respiratory rates were increased at 2 to 8 minutes and then showed a decrease at the 12 to 14-minute mark in both the doxapram and aminophylline groups (P < 0.05). No difference was noted between the two groups. BIS values were increased in both the doxapram and aminophylline groups at 4-10 minutes (P < 0.05). Heart rates were increased in the doxapram group for the first 8 minutes and at 1-2 minutes in the aminophylline group (P < 0.05). CONCLUSION: Aminophylline 3 mg/kg or doxapram 1 mg/kg shortened the time to spontaneous ventilation and improved early recovery from TIVA without appreciable side effects. The more rapid emergence correlates with higher BIS values when compared with the saline control group. The arousal and respiratory effects of aminophylline were comparable to those of doxapram.