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.

Table 2 Timeline of the disease course of the premature infant (December 14 to 19, 2021)

Parameter	Day 1	Day 2	Day 3	Day 5	Day 6
Disease course	Neonatal ICU				Clinical death
WBC as × 109/L	7.58	23.17	11.51	12.67
NEUT%	53.80	64.90	64.50	80.00
NEUT as × 109/L	4.08	15.06	7.42	10.14
LYMPH%	36.80	19.70	15.60	12.1
HGB in g/L	182.00	165.00	96.00	93.00
PLT as × 109/L	223.00	294.00	168.00	108.00
PT in s	71.90	NP	22.90	NP
PT as %	10.00	NP	39.90	NP
INR	6.16	NP	1.79	NP
FIB in g/L	1.42	NP	0.69	NP
APTT in s	41.30	NP	41.00	NP
TT in s	14.80	NP	19.20	NP
D-dimer in μg/mL	1.69	NP	5.13	NP
TP in g/L	44.55	NP	42.20	NP
ALB in g/L	26.83	NP	31.10	NP
AST in U/L	49.18	NP	165.30	NP
ALT in U/L	20.64	NP	55.10	NP
BUN in mmol/L	2.84	NP	12.20	NP
Cr in μmol/L	46.05	NP	64.5	NP
CK in U/L	150.12	NP	1313.75	NP
GLU in mmol/L	2.87	4.64	7.76	6.35	4.48
Ca2+ in mmol/L	2.14	NP	1.75	NP
Oxygen therapy	IMV	IMV	IMV	IMV
FiO2	80%	60%	60%	45%	40%
PEEP in cmH2O	6	5	5	4	4
PO2 in mmHg	136	83.8	267	81	119
OI in mmHg	170	140	445	180	297.5
PCO2 in mmHg	13.8	30.8	29.5	42	38
MetHb	3.3%	2%	NP	2%
pH	7.351	7.312	7.212	7.26	7.35
Lactates	NP	1.5	8.5	NP
Bicarbonate	7.5	15.5	11.8	23.8	21.6

ALB: Albumin; ALT: Alanine transaminase; APTT: Activated partial thromboplastin time; AST: Aspartate transaminase; BUN: Blood urea nitrogen; CK: Creatine kinase; Cr: Creatinine; CRP: C-reactive protein; FIB: Fibrinogen; GLU: Glucose; HGB: Hemoglobin; ICU: Intensive care unit; IMV: Invasive mechanical ventilation; INR: International normalized ratio; LYMPH: Lymphocyte; MetHb: Methemoglobin; NEUT: Neutrophil; NP: Not performed; OI: Oxygenation index; PCO₂: Carbon dioxide partial pressure; PCT: Procalcitonin; PEEP: Positive end-expiratory pressure; PLT: Platelet; PO₂: Oxygen partial pressure; PT: Prothrombin time; TP: Total protein; TT: Thrombin time; WBC: White blood cell.