Acquired methemoglobinemia in a third trimester puerpera and her premature infant with sodium nitrite poisoning: A case report

Table 1 Timeline of the disease course of the puerpera (December 14 to 20, 2021)

Parameter	Day 1		Day 2	Day 3	Day 4	Day 5	Day 6	Day 7
Disease course	Hospitalization/ICU				Maternity ward			Hospital discharge
WBC as × 109/L	13.64		15.78	12.24	11.39	10.12	6.82	4.77
NEUT as %	74.00		87.5	80.6	83.6	81.4	75.6	60.7
NEUT as × 109/L	10.09		13.82	9.87	9.52	8.24	5.15	2.9
LYMPH as %	18.80		6.2	11.1	8.8	12.5	15.2	25.6
HGB in g/L	119.00		99.00	85.00	74.00	63.00	76.00	79.00
D-dimer in μg/mL	2.49		NP	5.88	5.41	4.02	NP	2.15
TP in g/L	73.84		56.70	54.50	50.40	50.60	NP	55.10
ALB in g/L	38.63		33.10	31.57	28.81	30.60	NP	31.90
BUN in mmol/L	1.88		2.33	2.95	5.3	5.36	NP	4.15
Cr in μmol/L	30.16		32.60	43	55.6	34.50	NP	33.90
GLU in mmol/L	30.16		7.7	6.1	5.8	4.0	NP	4.44
Mg2+ in mmol/L	0.82		0.71	NP	NP	NP	NP	0.73
CRP in mg/L	8.86		45.9		62.5	34.1		17.1
PCT in ng/mL	0.17		0.18		0.18	0.12	0.06	0.04
Oxygen therapy	Nasal catheter oxygen therapy	IMV		HFNC	Nasal catheter oxygen therapy
FiO2	5 L/min	80%	55%	40%	4 L/min	3 L/min	1 L/min
PEEP in cmH2O		10	5	NP	NP	NP	NP
PO2 in mmHg	115	200	146	196	185	157	101
OI in mmHg	280.49	250	265.45	490	500	475.76	404
PCO2 in mmHg	26.7	24.4	35	33	37.6	39.6	39.3
LAC in mmol/L	4.2		1.2	1.4	0.6	0.6	0.7
MetHb	28.8%		18.2%	17.7%	2.2%	0.9%	1%

ALB: Albumin; BUN: Blood urea nitrogen; Cr: Creatinine; CRP: C-reactive protein; GLU: Glucose; HFNC: High-flow nasal cannula oxygen therapy; HGB: Hemoglobin; ICU: Intensive care unit; IMV: Invasive mechanical ventilation; LAC: Lactic acid; LYMPH: Lymphocyte; MetHb: Methemoglobin; NEUT: Neutrophil; NP: Not performed; OI: Oxygenation index; PCO₂: Carbon dioxide partial pressure; PCT: Procalcitonin; PEEP: Positive end-expiratory pressure; PO₂: Oxygen partial pressure; TP: Total protein; WBC: White blood cell.