End-Tidal Carbon Dioxide Monitoring for Spontaneous Pneumothorax

Table 1

Comparison of general characteristics between PSP and SSP groups.

	Total (n = 50)	PSP (n = 33)	SSP (n = 17)	value
Age (yr)	29 (19–51)	20 (17–29)	56 (50–70)	<0.001
Male gender, no. (%)	37 (74.0)	27 (81.8)	10 (58.8)	0.099
Smoker, no. (%)	16 (32.0)	10 (30.3)	6 (35.3)	0.757
Pack years among smokers	5 (3–22)	5 (3–5)	29 (15–35)	0.012
Symptoms
Pleuritic pain, no. (%)	17 (34.0)	14 (42.4)	3 (17.6)	0.117
Dyspnea, no. (%)	22 (44.0)	17 (51.5)	11 (64.7)	0.548
Onset-to-visit interval (hr)	10 (4–24)	8 (4–24)	12 (2–28)	0.734
Underlying lung disease in SSP
Abnormal parenchyma, no. (%)			10 (58.8)
Infection, no. (%)			8 (47.1)
Malignancy, no. (%)			2 (11.8)
Pulmonary endometriosis, no. (%)			1 (5.9)
Initial SBP <90 mmHg or initial DBP <60 mmHg	9 (18)	5 (15.2)	4 (23.5)	0.467
Initial HR ≥120 or <60 rate/min	6 (12.0)	1 (3.0)	5 (29.4)	0.014
Initial RR > 20 rate/min	6(12.0)	2 (6.1)	4 (23.5)	0.161
Initial BT ≥37.3°C	1 (2.0)	0	1 (5.9)	0.340
Initial room-air SpO2 <90%	4 (8.0)	0	4 (23.5)	0.010
First episode PNX, no. (%)	14 (28.0)	12 (36.4)	2 (11.8)	0.099
Bilateral PNX, no. (%)	4 (8.0)	0	4 (23.5)	0.010
Size of PNX
Percentage of PNX	34.0 (15.0–53.3)	29.4 (15.0–52.6)	35.1 (23.0–72.1)	0.529
Large-size PNX, no. (%)	20 (40.0)	13 (39.4)	7 (41.2)	1.000
Closed tube thoracotomy, no. (%)	37 (74.0)	21 (63.6)	16 (94.1)	0.038
Subsequent surgical operation, no. (%)	22 (44.0)	17 (51.5)	5 (29.4)	0.229
Hospital days	6 (3–8)	6 (3–7)	8 (6–12)	0.003
Mortality, no. (%)	1 (2.0)	0	1 (5.9)	0.340

Median (interquartile range); PSP, primary spontaneous pneumothorax; SSP, secondary spontaneous pneumothorax; SBP, systolic blood pressure; DBP, diastolic blood pressure; HR, heart rate; RR, respiration rate; BT, body temperature; SpO₂, peripheral oxygen saturation; PNX, pneumothorax.