Association of carbon monoxide poisonings and carboxyhemoglobin levels with COVID-19 and clinical severity

Table 1 Basal and laboratory findings of the patients

			Disease periods
		All patients (n = 479), mean ± SD	Pre-pandemic, (n = 253), mean ± SD	Pandemic (n = 226)				P value
				Non-COVID-19 (n = 83), mean ± SD	Mild COVID-19 (n = 60), mean ± SD	Moderate COVID-19 (n = 45), mean ± SD	Severe COVID-19 (n = 38), mean ± SD
Baseline characteristics
Age (year)		54.93 ± 11.51	50.56 ± 11.24	56.87 ± 10.29	57.32 ± 9.58	65.98 ± 6.70	62.87 ± 7.50	< 0.001
Gender	Female	187 (39)	98 (38.7)	38 (45.8)	24 (40)	16 (35.6)	11 (28.9)	0.3461
	Male	292 (61)	155 (61.3)	45 (54.2)	36 (60)	29 (64.4)	27 (71.1)
Exposure time (h)		4.31 ± 1.74	4.09 ± 1.86	4.84 ± 1.98	4.25 ± 1.26	4.69 ± 1.24	4.24 ± 1.23	0.201
Laboratory findings
Arterial blood gas	pH (7.35-7.45)	7.28 ± 0.15	7.35 ± 0.10	7.29 ± 0.12	7.23 ± 0.12	7.14 ± 0.16	7.05 ± 0.16	< 0.001
	PaCO2 (mmHg) (32-45)	47.07 ± 8.34	43.32 ± 6.81	46.04 ± 7.90	51.10 ± 6.34	55.67 ± 4.93	57.76 ± 4.49	< 0.001
	PaO2 (mmHg) (80-100)	86.92 ± 8.01	89.63 ± 7.62	87.10 ± 6.44	83.01 ± 7.40	82.81 ± 6.50	79.50 ± 7.18	< 0.001
	K+ (mmol/L) (3.4-4.5)	4.20 ± 0.71	4.00 ± 0.58	4.01 ± 0.55	4.34 ± 0.78	4.64 ± 0.64	5.25 ± 0.63	< 0.001
	Na+ (mmol/L) (135-149)	138.04 ± 4.52	138.52 ± 4.70	137.35 ± 4.33	137.98 ± 4.22	17.13 ± 4.23	137.48 ± 4.33	0.239
	Ca++ (mmol/L) (1.15-.29)	1.16 ± 0.26	1.18 ± 0.25	1.19 ± 0.26	1.11 ± 0.20	1.07 ± 0.29	1.06 ± 0.37	0.02
	Cl- (mmol/L) (98-106)	99.90 ± 8.27	99.97 ± 7.14	100.01 ± 5.72	100.01 ± 12.69	99.98 ± 10.19	98.92 ± 9.05	0.944
	BS (mg/Dl) (70-105)	129.59 ± 24.66	120.49 ± 20.98	129.35 ± 21.89	132.75 ± 24.18	155.91 ± 21.58	154.50 ± 15.73	< 0.001
	HCO3 (mmol/L) (22-26)	17.68 ± 6.18	20.31 ± 5.46	17.91 ± 5.49	15.13 ± 4.59	12.47 ± 4.62	9.92 ± 3.73	< 0.001
	BE (mmol/L) (-3.0-3.0)	7.09 ± 5.56	4.76 ± 4.68	6.76 ± 4.85	9.22 ± 4.43	11.79 ± 4.48	14.41 ± 3.58	< 0.001
	Lactate (mmol/L) (0.5-1.6)	2.85 ± 1.99	1.89 ± 1.24	2.60 ± 1.57	3.54 ± 1.44	4.87 ± 1.92	6.33 ± 1.76	< 0.001
	COHb (%) (0.5-1.5)	29.68 ± 7.85	26.19 ± 6.68	27.63 ± 5.37	34.25 ± 5.00	37.35 ± 5.38	41.08 ± 7.55	< 0.001
Troponin I (ng/mL) (0.0-0.05)		0.40 ± 1.91	0.11 ± 0.25	0.20 ± 0.28	0.42 ± 0.35	0.82 ± 0.31	1.09 ± 0.50	< 0.001

¹Chi-Square test.

Other P values were calculated by the Kruskal-Wallis H test. Bold values indicate significance at P < 0.05. SD: Standard Deviation; COVID-19: Coronavirus disease 2019; pH: Potential of Hydrogen; PaCO₂: Partial pressure of carbon dioxide; PaO₂: Partial arterial oxygen pressure; K⁺: Potassium; Na⁺: Sodium; Ca⁺⁺: Calcium; Cl^-: Chloride; BS: Blood sugar; HCO₃: Bicarbonate; BE: Base Excess; COHb: Carboxyhemoglobin.