A novel nomogram for predicting the decision to delayed extubation after thoracoscopic lung cancer surgery

Figures & data

Figure 1. Forest plot of independent predictors of delayed extubation. BMI: body mass index; FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity; TPVB: thoracic paravertebral blockade.

Figure 2. A novel nomogram to predict delayed extubation. The nomogram provides a visual point system based on the combination of patient characteristics (age, BMI, FEV₁/FVC, lymph nodes calcification, combined with TPVB, intraoperative transfusion, operative time and operation later than 6 p.m.) to estimate the probability of delayed extubation. To calculate the probability of delayed extubation, the points of eight variables determined on the scale were added to obtain the total points. Draw a vertical line from the total points scale to the last axis to obtain the corresponding probability of delayed extubation. BMI: body mass index; FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity; TPVB: thoracic paravertebral blockade.

Table 1. Preoperative and intraoperative patient characteristics.

	Development cohort (n = 8716)			Validation cohort (n = 3676)
Variables^a	Delayed extubation (n = 139)	In-OR extubation (n = 8577)	p Value	Delayed extubation (n = 50)	In-OR extubation (n = 3626)	p Value
Age, years	62.2 ± 10.0	57.8 ± 10.6	<.001^b	60.9 ± 11.1	58.1 ± 10.7	.067
Sex			.002^b			.127
Male sex	73 (52.5)	3391 (39.5)		25 (50.0)	2198 (60.6)
Female sex	66 (47.5)	5186 (60.5)		25 (50.0)	1428 (39.4)
BMI, kg/m^2	24.0 ± 3.5	23.2 ± 3.0	.013^b	24.0 ± 3.0	23.3 ± 3.0	.093
ASA grade			.267			.545
I	8 (5.8)	808 (9.4)		2 (4.0)	291 (8.0)
II	114 (82.0)	6906 (80.5)		44 (88.0)	2997 (82.7)
III/IV	17 (12.2)	863 (10.1)		4 (8.0)	338 (9.3)
FEV1/FVC, %	98.7 ± 11.1	101.2 ± 7.5	.008b	101.7 ± 10.1	101.2 ± 8.3	.677
DLCO%	90.7 ± 13.7	94.5 ± 15.0	.003b	92.4 ± 17.0	94.5 ± 16.5	.379
Comorbidity
Hypertension	12 (8.6)	565 (6.6)	.336	5 (10.0)	290 (8.0)	.795
Diabetes mellitus	5 (3.6)	277 (3.2)	.806	3 (6.0)	131 (3.6)	.428
Coronary artery disease	1 (0.7)	37 (0.4)	1.000	2 (2.6)	56 (1.1)	.199
Stroke/TIA	0 (0)	17 (0.2)	1.000	0 (0)	17 (0.5)	1.000
Chemoradiotherapy	1 (0.7)	30 (0.3)	.393	2 (4.0)	4 (0.1)	.003b
Tumour size, cm	2.1 ± 1.4	1.7 ± 1.1	.003^b	2.1 ± 1.1	1.7 ± 1.0	.016b
Advanced T stage (T ≥ 2)	23 (16.5)	901 (10.5)	.022^b	11 (22.0)	319 (8.8)	.004b
Hypoxemia	7 (5.0)	347 (4.0)	.557	5 (10.0)	111 (3.1)	.020b
Lymph nodes calcification	17 (12.2)	391 (4.6)	<.001^b	5 (10.0)	177 (4.9)	.099
Clinical nodal involvement	13 (9.4)	426 (5.0)	.019^b	4 (8.0)	169 (4.7)	.296
Pleural adhesions	3 (2.2)	198 (2.3)	1.000	3 (6.0)	67 (1.8)	.069
Type of resection			.724			.860
Segmentectomy resection	27 (19.4)	1771 (20.6)		11 (22.0)	836 (23.1)
Lobectomy resection	112 (80.6)	6806 (79.4)		39 (78.0)	2790 (76.9)
Approach			.183			1.000
VATS	136 (97.8)	8190 (95.5)		48 (96.0)	3498 (96.5)
RATS	3 (2.2)	387 (4.5)		2 (4.0)	128 (3.5)
Anaesthesia type			.001^b			.066
GA alone	136 (97.8)	7606 (88.7)		44 (88.0)	2793 (77.0)
Combined with TPVB	3 (2.2)	971 (11.3)		6 (12.0)	833 (23.0)
Location of resection			.530			.819
Left resection	57 (41.0)	3293 (38.4)		20 (40.0)	1393 (38.4)
Right resection	82 (59.0)	5284 (61.6)		30 (60.0)	2233 (61.6)
Conversion to thoracotomy	9 (6.5)	113 (1.3)	<.001^b	2 (4.0)	33 (0.9)	.081
Intraoperative arrhythmia	3 (2.2)	146 (1.7)	.734	2 (4.0)	49 (1.4)	.152
Intraoperative transfusion	8 (5.8)	81 (0.9)	<.001^b	4 (8.0)	33 (0.9)	.001^b
Operative time, mins	117.0 ± 49.7	97.2 ± 36.4	<.001^b	124.7 ± 67.2	96.4 ± 35.8	.001^b
Attending handoff	9 (6.5)	107 (1.2)	<.001^b	7 (14%)	54 (1.5)	<.001^b
Operation later than 6 p.m.	44 (31.7)	345 (4.0)	<.001^b	22 (44.0)	134 (3.7)	<.001^b

^aContinuous data are shown as mean ± standard deviation and categoric data as number (%).

^bStatistically significant (P<0.05).

Note: OR: operating room; BMI: body mass index; ASA: American Society of Anaesthesiology; FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity; DLCO: diffusion capacity for carbon monoxide; TIA: transient cerebral ischemic attack; VATS: video-assisted thoracoscopic surgery; RATS: robotic-assisted thoracoscopic surgery; GA: general anaesthesia; TPVB: thoracic paravertebral blockade.

Figure 3. AUROC curve analysis of the development (A) and validation cohort (B).

Figure 4. Internal calibration curves. A completely accurate prediction model will generate a plot where the probability of the actual observed and predicted corresponding completely and fall along the 45°line (dashed line). The apparent calibration curve (dotted line) represents the calibration of the model in the development data set, while the bias-corrected curve (solid line) is the calibration result after correcting the optimism with the 1000 bootstrap-resampling.

Figure 5. The DCA shows the clinical usefulness of the nomogram. The Y-axis represents net benefit. The bold solid black line is a nomogram predicting the risk of delayed extubation. The solid grey line indicates that all patients occurred delayed extubation, while the fine solid black line indicates that no patient occurred delayed extubation. This DCA could provide a larger net benefit, with ranges of 0% to 30%. DCA: decision curve analysis .

Data availability statement

Our research team could provide original data under reasonable request and with permission from Shanghai Chest Hospital.