Perioperative respiratory muscle training improves respiratory muscle strength and physical activity of patients receiving lung surgery: A meta-analysis

Table 1 Characteristics of included studies

Ref.	Year	Country	Sample size	Surgery type	Intervention	Control	Initial training pressure (%)	Training time (min/d)	Sessions (n/wk)	Duration (wk)
Weiner et al[22]	1997	Israel	IMT: 17, Con: 15	NR	Preoperative and postoperative IMT, incentive spirometry	Usual care	15	60	6	14
Brocki et al[23]	2016	Denmark	IMT: 34, Con: 34	VATS: 35, thoracotomy: 33	Preoperative IMT 30% MIP, postoperative: 15% MIP, breathing exercises, early mobilization	Breathing exercises, early mobilization	30	15	7	2
Brocki et al[24]	2018	Denmark	IMT: 34, Con: 34	VATS: 35, thoracotomy: 33	Preoperative IMT 30% MIP, postoperative: 15% MIP, breathing exercises, early mobilization	Breathing exercises, early mobilization	30	15	7	2
Taşkin et al[25]	2018	Turkey	RMT: 20, Con: 20	Thoracotomy	Postoperative RMT, chest physiotherapy, early mobilization	Chest physiotherapy, early mobilization	15	Six sessions consisting of 3 sets of 10 breaths	5	NR
Messaggi-Sartor et al[26]	2019	Spain	RMT: 16, Con: 21	VATS: 3, thoracotomy: 34	Postoperative RMT, aerobic exercise	Usual care	30	60	3	8
Kendall et al[27]	2020	Portugal	IMT: 13, EMT: 13, IMT + EMT: 18, Con: 19	Thoracotomy	Postoperative IMT or EMT or IMT + EMT, usual care	Usual care	25	15	7	8
Laurent et al[28]	2020	France	RMT: 14, Con: 12	VATS or thoracotomy	Preoperative RMT, usual chest physical therapy	Usual chest physical therapy	30	30	4	3

IMT: Inspiratory muscle training; EMT: Expiratory muscle training; Con: Control; RMT: Respiratory muscle training; VATS: Video-assisted thoracoscopy surgery; NR: Not reported; MIP: Maximal inspiratory pressure; MEP: Maximal expiratory pressure.

Table 2 Quality assessment for included trials according to Physiotherapy Evidence Database scoring scale

Ref.	1	2	3	4	5	6	7	8	9	10	11	Total score
Weiner et al[22]	N	Y	N	Y	N	N	N	N	Y	Y	Y	5/10
Brocki et al[23]	Y	Y	Y	Y	N	N	N	Y	Y	Y	Y	7/10
Brocki et al[24]	Y	Y	Y	Y	N	N	N	Y	Y	Y	Y	7/10
Taşkin et al[25]	Y	Y	N	Y	N	N	Y	Y	Y	Y	Y	7/10
Messaggi-Sartor et al[26]	Y	Y	N	Y	N	N	Y	Y	Y	Y	Y	7/10
Kendall et al[27]	Y	Y	N	Y	N	N	N	Y	Y	Y	Y	6/10
Laurent et al[28]	Y	Y	N	Y	N	N	N	Y	Y	Y	Y	6/10

N: No criteria or not satisfied; Y: Yes (criteria satisfied); 1: Eligibility criteria; 2: Random allocation; 3: Concealed allocation; 4: Baseline comparability; 5: Blind subjects, 6: Blind therapists; 7: Blind assessors; 8: Adequate follow-up; 9: Intention-to-treat analysis; 10: Between-group comparisons; 11: Point estimates and variability. The total Physiotherapy Evidence Database score is the sum of items 2 to 11, which relate to internal validity. Item 1 is reported to indicate external validity.

Table 3 Subgroup analysis about primary outcomes

	No. of studies	Mean	95%CI	P value	I2 (%)	Pheterogeneity
MIP
Intervention time
Preoperative	1	12.33	-5.49, 5.49	> 0.999	-	-
Postoperative	2	12.33	3.55, 21.11	0.006	0.0	0.67
Training method
IMT	3	9.53	3.98, 15.08	< 0.001	44	0.17
EMT	1	9.00	-9.00, 27.00	0.33	-	0.13
RMT	3	6.97	-2.81, 16.74	0.16	64	-
MEP
Intervention time
Preoperative	1	27	18.67, 35.33	< 0.001	-	-
Postoperative	2	15.83	-1.80, 33.45	0.08	58	0.12
Training method
IMT	2	-3.49	-10.57, 3.60	0.33	0	0.65
EMT	1	1.70	-14.67 to 18.07	0.84	-	-
RMT	3	20.72	8.60, 32.84	< 0.001	60	0.08

MIP: Maximal inspiratory pressure; MEP: Maximal expiratory pressure; IMT: Inspiratory muscle training; EMT: Expiratory muscle training; RMT: Respiratory muscle training.

Table 4 Results about the effect of respiratory muscle training on patients receiving lung resection

	No. of studies	Mean	95%CI	P value	I2 (%)	Pheterogeneity
Primary outcomes
Respiratory function
MIP (cmH2O)	5	8.13	1.31, 14.95	0.02	66	0.02
MEP (cmH2O)	4	13.51	-4.47, 31.48	0.14	91	< 0.001
Secondary outcomes
Physical activity	2	-	-	0.006/0.035	-	-
Exercise capacity
6MWD (m)	3	9.96	-34.61, 54.54	0.66	63	0.06
CPET/VO2peak (mL/min/kg)	2	2.44	-2.36, 7.24	0.32	96	< 0.001
Pulmonary function
FEV1 (L)	3	0.06	-0.07, 0.19	0.39	13	0.32
FVC (L)	2	0.29	-0.05, 0.64	0.10	0	0.96
Quality of life
Pain (VAS)	2	0.67	-0.99, 2.32	0.43	61	0.11
Dyspnoea (VAS)	2	-0.16	-0.58, 0.25	0.44	0	0.61
EORTC QLQ-C30	1	-	-	-	-	-

MIP: Maximal inspiratory pressure; MEP: Maximal expiratory pressure; FEV1: Forced expiratory volume in one second; FVC: Forced vital capacity; 6MWD: 6-min walking distance; CPET: Cardio-pulmonary exercise test; VO_2peak: Peak oxygen consumption; MET: Metabolic equivalent; VAS: Visual analog scale.