Table 3.

Summary of Reported Cases of Perioperative Management of Congenital Methemoglobinemia

Author	Age/Sex	Associated Conditions	Surgery	Anesthetic Management	Postoperative course	Outcome
Chisholm et al19	24 years old/ Female	Nil	Evacuation of retained product of conception	Anesthesia was induced with intravenous propofol and fentanyl and maintained with 50% nitrous oxide in oxygen with incremental propofol boluses.	Uneventful	Discharged home the next day
Baraka et al20	22 years old/ Male		Turbinectomy	Arterial cannula inserted, then lidocaine (1mg/kg) was administered intravenously. The patient developed sudden unconsciousness, and apnea, with severe cyanosis and desaturation (79%). 100% oxygen and methylene blue (1mg/kg) were administered. The patient regained consciousness but the surgery was cancelled.	Stable course	Not reported
Maurtua et al21	33 years old/ Female	Nil	Laparoscopic excision of a right rudimentary fallopian tube and hysteroscopy	Arterial line was inserted, followed by intravenous induction with fentanyl, lidocaine, propofol and atracurium	Stable perioperative course, Arterial blood gas (ABG) taken in the recovery room showed no change in MetHb in levels from the baseline.	Not reported
Baraka et al22	26 years old/ Male	Nil	Turbinectomy	Arterial line with baseline blood gas sampling, prophylactic methylene blue 1% administered at a dose of 1mg/kg intravenously, followed by IV induction with lidocaine (1mg/kg), propofol (2mg/kg) and rocuronium (0.6mg/kg). Anesthesia was maintained with isoflurane 1 to 2% in 50% of oxygen.	Uneventful course. MetHb fraction was 0.01 postoperatively and increased to 0.026 on the second day to reach 0.094 on the fifth day.	Not reported
Sharma et al23	9 years old/ Male	Osler-Weber-Rendu syndrome and bilateral pulmonary arteriovenous malformation	Cerebral angiography	Radial artery cannulated, followed by intravenous (IV) induction with thiopentone sodium (150 mg), and rocuronium (25 mg). Inhalational anesthesia was maintained with 0.8–1% isoflurane. Reversed with IV neostigmine 1.5 mg and atropine 0.6 mg before extubation.	Stable postoperative period.	Not reported
Melarkode et al14	60 years old/ Female	Nil	Mastectomy	Arterial line was inserted before anesthesia, induction with IV fentanyl and propofol. Inhalational anesthesia was maintained with Isoflurane.	Uneventful perioperative course	Discharged home two days after the surgery.
Lin et al6	35 years old/ Female	Nil	Uterine myomectomy	Following preoxygenation with 100% oxygen, anesthesia was induced with IV midazolam (2.5 mg), fentanyl (75 mcg), lidocaine (50 mg), propofol (2mg/kg) and rocuronium (50 mg). Extubated at the end of the surgery	Smooth recovery.	Discharged home two days later.
Champigneulle24	78 years old/ Male	Nil	Aortic valve replacement	General anesthesia was induced with the target-controlled infusion of propofol and remifentanil and a bolus of atracurium.	Extubated a few hours after the surgery.	Discharged from the ICU on day 2 and from the hospital on day 13 without complications.
Gupta et al25	26 years old/ Female	Nil	Emergency cesarean section	Spinal anesthesia with 0.5% bupivacaine (2mL).	Stable postoperative course.	Not reported
Yin et al26	22 years old/ Female	Nil	Elective induction of Labor	Remifentanil as intravenous labor analgesia, at an infusion of 0.025 mcg/kg/min with a 25 mcg bolus and continuous methemoglobin saturation (CO-Oximeter) monitoring.	Smooth recovery	Discharged home on postpartum day 2.
Ri et al4	32 years old/ Male	Hb M disease	Thyroidectomy	Arterial line was inserted followed by IV induction with propofol (200 mg) and rocuronium (90 mg). Anesthesia was maintained with 1.5–2% sevoflurane with FiO2 at 0.6. Target remifentanil set at 2–3 ng/mL IV. Frequent ABG samples taken intraoperatively. Twenty minutes post-induction, SpO2 was 65–75% and cyanosis was observed. FiO2 increased to 1.0. Extubated after two hours of surgery.	Received oxygen at 6 L/min via face mask in the recovery and weaned to room air later.	Uneventful postoperative course and discharged home on day 5 after surgery.
Choi et al27	15 years old/ female	Nil	Dental extraction	Remifentanil and propofol infusion started at 0.5 mcg/kg/hr and 100 mcg/kg/min respectively to facilitate arterial cannulation, followed by an induction dose of propofol (150 mg) without neuromuscular blockade. Anesthesia was maintained with isoflurane inhalation and IV remifentanil. CO-Oximeter used intraoperatively for continuous measurement of MethHgb along with cerebral oximetry. Received 4 mg each of dexamethasone and ondansetron as well as 50 mcg of fentanyl intraoperatively. Extubated uneventfully at the end of the surgery	Placed on 6 L/min of oxygen by the face mask and monitored for four hours postoperatively.	Discharged home on the same day of surgery
Karimbanakkal et al28	Middle-aged, Male	Diabetes, hypertension, coronary artery disease, post-renal transplant	Parathyroidectomy	After preoxygenation with 100% oxygen, induced with IV etomidate (16 mg), fentanyl (100 mcg), and atracurium (40 mg). Anesthesia was maintained with sevoflurane and IV fentanyl 50 mcg/hr. Arterial line inserted post-induction. Extubated after given reversal. Maintained stable hemodynamic throughout the surgery	Shifted to intensive care unit post-operatively and placed on 4–6 L/min oxygen via Hudson mask.	Not reported