Rere-s-18-00395 (6).pdf

Respiratory Research Rectal, central venous, gastric and bladder pressures versus esophageal pressure for the measurement of cough strength: a prospective clinical comparison --Manuscript Draft-Manuscript Number: Full Title:

Rectal, central venous, gastric and bladder pressures versus esophageal pressure for the measurement of cough strength: a prospective clinical comparison

Article Type:

Research

Funding Information:

Instituto de Salud Carlos III (FIS PI030127)

Abstract:

Background: Cough pressure, an expression of expiratory muscle strength, is usually measured with esophageal or gastric balloons, but these invasive catheters are not always practical nor comfortable for the patient. Because pressure in the thorax and abdomen are expected to be similar during a cough, we hypothesized that measurement at other thoracic or abdominal locations might also be similar as well as useful in clinical scenarios. This study aimed to compare cough pressures measured at thoracic and abdominal sites that could serve as alternatives to esophageal pressures (PES). Methods: Nine patients scheduled for laparotomy were asked to cough as forcefully as possible from total lung capacity in supine position. Three cough maneuvers were performed while PES (the gold standard) as well as gastric, central venous, bladder and rectal pressures (PGA, PCV, PBL, and PREC, respectively) were measured simultaneously. The intraclass correlation coefficient (ICC) was used to evaluate the reliability of the measurements in each patient at each site, and Bland Altman plots were used to evaluate agreement between PES and the measurements at the other sites. Results: Mean(SD) maximum pressures were as follows: PES, 116(29); PGA, 120(35); PCV, 116(30); PBL, 125(36), and PREC, 116(34) cmH2O. The ICCs showed excellent repeatability of the measurements at each different site (p<0.001). The Bland Altman plots showed minimal differences between PES, PGA, PCV, and PREC. PBL was higher than the other pressures in most patients, and the difference between PES and PBL was slightly larger. Conclusions: Cough pressure can be measured in the esophagus, stomach, superior vena cava or rectum, since their values are similar. It can also be measured in the bladder, although the value will be slightly higher. These results potentially facilitate the assessment of dynamic expiratory muscle strength with fewer invasive catheter placements in most hospitalized patients, thus providing an option that will be particularly useful in those undergoing thoracic or abdominal surgery. Trial registration: NCT02957045 registered at November 7, 2016. Retrospectively registered.

Corresponding Author:

Lluís Gallart, M.D., PhD Consorci Parc de Salut MAR de Barcelona SPAIN

Prof Lluís Gallart

Corresponding Author Secondary Information: Corresponding Author's Institution:

Consorci Parc de Salut MAR de Barcelona

Corresponding Author's Secondary Institution: First Author:

Lluís G. Aguilera, M.D.

First Author Secondary Information: Order of Authors:

Lluís G. Aguilera, M.D. Lluís Gallart, M.D., PhD

Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation

Juan C. Alvarez, M.D. Jordi Vallès, M.D., Ph.D. Joaquim Gea, M.D., Ph.D. Order of Authors Secondary Information:

Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation

Manuscript

Click here to download Manuscript Aguilera Pcough body text MS.docx

Click here to view linked References

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

1

TITLE PAGE

2

Rectal, central venous, gastric and bladder pressures versus esophageal

3

pressure for the measurement of cough strength: a prospective clinical

4

comparison

5 6

AUTHORS

7

Lluís G. Aguilera1

8

[email protected]

9

Lluís Gallart1*

10

[email protected]

11

Juan C. Álvarez1

12

[email protected]

13

Jordi Vallès1

14

[email protected]

15

Joaquim Gea2

16

[email protected]

17 18

1

Department of Anesthesiology, Parc de Salut MAR, Institut Hospital del Mar

19

d'Investigacions Mèdiques (IMIM), Universitat Autònoma de Barcelona (UAB),

20

Barcelona, Spain.

21

2

Department of Respiratory Medicine, Parc de Salut MAR, Institut Hospital del Mar

22

d'Investigacions Mèdiques (IMIM), Universitat Pompeu Fabra (UPF), CIBERES (ISC

23

III).

24

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

25

*Corresponding author:

26

Lluís Gallart, MD

27

Department of Anesthesiology. Parc de Salut MAR. Faculty of Medicine UAB – UPF.

28

Passeig Maritim 25

29

08003 Barcelona, Spain.

30

Telephone Number: 34 93 248 33 50

31

Fax Number: 34 93 248 36 17

32

E-mail Address: [email protected]

33 34

Abstract

35

Background: Cough pressure, an expression of expiratory muscle strength, is usually

36

measured with esophageal or gastric balloons, but these invasive catheters are not always

37

practical nor comfortable for the patient. Because pressure in the thorax and abdomen are

38

expected to be similar during a cough, we hypothesized that measurement at other thoracic

39

or abdominal locations might also be similar as well as useful in clinical scenarios. This study

40

aimed to compare cough pressures measured at thoracic and abdominal sites that could

41

serve as alternatives to esophageal pressures (PES).

42

Methods: Nine patients scheduled for laparotomy were asked to cough as forcefully as

43

possible from total lung capacity in supine position. Three cough maneuvers were

44

performed while PES (the gold standard) as well as gastric, central venous, bladder and

45

rectal pressures (PGA, PCV, PBL, and PREC, respectively) were measured simultaneously. The

46

intraclass correlation coefficient (ICC) was used to evaluate the reliability of the

47

measurements in each patient at each site, and Bland Altman plots were used to evaluate

48

agreement between PES and the measurements at the other sites.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

49

Results: Mean (±SD) maximum pressures were as follows: PES, 11629; PGA, 12035; PCV,

50

11630; PBL, 12536, and PREC, 11634 cmH2O. The ICCs showed excellent repeatability

51

of the measurements at each different site (p<0.001). The Bland Altman plots

52

showed minimal differences between PES, PGA, PCV, and PREC. PBL was higher than the

53

other pressures in most patients, and the difference between PES and PBL was slightly

54

larger.

55

Conclusions: Cough pressure can be measured in the esophagus, stomach, superior

56

vena cava or rectum, since their values are similar. It can also be measured in the

57

bladder, although the value will be slightly higher. These results potentially facilitate the

58

assessment of dynamic expiratory muscle strength with fewer invasive catheter placements

59

in most hospitalized patients, thus providing an option that will be particularly useful in

60

those undergoing thoracic or abdominal surgery.

61

Trial registration: NCT02957045 registered at November 7, 2016. Retrospectively

62

registered.

63 64

Key words: Respiratory Muscles [A02.633.567.900]

65

Abdominal Muscles [A02.633.567.050]

66

Cough [C23.888.852.293]

67

Laparotomy [E04.406]

68 69 70

Background Cough is a physiological response to airway secretions. Thus, the inability to

71

cough forcefully enough to remove secretions would increase the risk of pulmonary

72

complications such as atelectasis or pneumonia. This inability is observed in

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

73

neuromuscular or respiratory diseases and is particularly likely after abdominal or

74

thoracic surgery, when pain, surgical injury and/or the residual effect of anesthetics

75

come into play [1-3].

76

Because a cough is a voluntary maneuver that is easy for a patient to produce

77

without training, cough pressure measurements at various sites can be obtained

78

readily in clinical situations, in contrast to the often used maximum mouth expiratory

79

pressure recorded during a static artificial maneuver [4, 5] that must be learned. Cough

80

pressure is usually measured with balloon catheters that record maximum gastric or

81

esophageal pressures (PGA, PES) [4-6]. It is not always practical to use these catheters,

82

however, and they can cause discomfort [4, 7]. Furthermore, they cannot be used in certain

83

situations, such as during postoperative recovery from gastrointestinal surgery. Other points

84

of measurement that might potentially be used to reflect cough pressure include central

85

venous pressure (PCV), which has been used as an alternative to PES [8], and bladder (PBL)

86

or rectal (PREC) pressures, which in turn have been used as alternatives to PGA [8-11].

87

However, none of these pressures have yet been used to evaluate expiratory muscle

88

strength, even though many hospitalized patients have a catheter already placed in the

89

superior cava or in the bladder.

90

We hypothesized that these catheters could be suitable for measuring cough pressure

91

without compromising patient comfort, as occurs with the placement of a gastric or

92

esophageal balloon. We also reasoned that placement of a rectal balloon catheter, which

93

does not cause the nausea associated with esophageal or gastric balloons, could also

94

measure cough pressure comfortably. If these hypotheses are correct, wider clinical use of

95

cough pressure to reflect respiratory muscle strength and possible risk of respiratory

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

96

compromise might be facilitated. The aim of this study was to evaluate the use of PCV, ,

97

PBL, and PREC as alternatives to PES or PGA for the measurement of cough pressure.

98 99 100

Methods Patients Adult patients scheduled for open-midline laparotomy for colon cancer surgery,

101 102

which required placement of central venous and bladder catheters were enrolled

103

prospectively. Exclusion criteria included rectal surgery, chronic obstructive

104

pulmonary disease [12], neuromuscular disorders [1], chronic pain, and factors that

105

could impede an adequate recording of the research protocol variables. The study was approved by the clinical research ethics committee of Parc de Salut

106 107

Mar (CEIC-Parc de Salut Mar) and by the Spanish Agency for Medicines and Health Products

108

(AEMPS). All patients signed an informed consent form before entering the study, and we

109

provided each with an insurance policy to cover care in the event of adverse events of the

110

procedures.

111

Interventions and measurements All patients underwent forced spirometry measurement (Datospir 500, SIBEL,

112 113

Barcelona, Spain) the day before surgery. Reference values were those for a Mediterranean

114

population [12]. An epidural catheter was placed for postoperative analgesia but no epidural

115

drugs were administered before the study. Pressures were measured with catheters placed in esophagus, stomach, superior vena

116 117

cava, bladder and rectum as follows:

118

-

119

PES and PGA were measured with compliance balloon catheters (esophageal catheter Jaeger 720199, Viasys Healthcare, Hoechberg, Germany) as previously described [5].

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

120

The catheters were introduced nasally under local anesthesia and the balloons were

121

filled with 1-2 mL of air.

122

-

PCV was measured from the distal port of a double-lumen catheter (CV-26702-E, Arrow,

123

Erding, Germany) placed through the subclavian or internal jugular veins [13]. Correct

124

positioning was checked with the PCV waveform [14].

125

-

drained and 50 mL of a 0.9% saline solution was instilled [8, 11, 15].

126 127 128 129

PBL was measured with a transurethral (Foley) catheter inserted after the bladder was

-

PREC was measured with a compliance balloon inserted 10 cm inside the rectum and filled with 5 mL of air [10]. All the pressure curves were displayed on a screen and recorded with a data

130

acquisition system (Acknowledge and MP100, Biopac, Santa Barbara, CA, USA) for off-line

131

analysis. Patients lay in supine position and all the pressure transducers were calibrated and

132

aligned with the axillary midline.

133

The correct placement of all catheters was assessed by asking the patient to perform

134

a sharp sniff and a cough maneuver while the researcher monitored the signal on the

135

computer screen [5]. Once all catheters were inserted and after a 3-minute resting period,

136

baseline respiratory pattern and pressures were recorded.

137

Cough pressure was then measured at all points. Patients were asked, always by the

138

same researcher (L.G.A.), to cough as forcefully as possible [5] from total lung capacity

139

(TLC). The pressures generated by three valid maneuvers, separated by pauses of 5–10

140

seconds, were recorded as the difference between the baseline pressure at relaxed end-

141

expiratory lung volume and the peak pressure attained during each cough from TLC, as

142

previously described [4, 6].

143

Soon after the end of the protocol, the patients were asked to indicate which

144

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

catheters caused the least and the most discomfort.

145 146

Statistical analysis The sample size was calculated to provide a statistical power of 80% based on

147 148

the range of cough pressure values obtained at the different sites during an earlier

149

study [6]. Reliability of the cough pressure measurements across the three maneuvers of

150 151

each site were evaluated with the intraclass correlation coefficient (ICC). Likewise,

152

agreement between PGA, PCV, PBL and PREC and the gold-standard (PES) was evaluated

153

with Bland-Altman plots [16]. PES rather than PGA was chosen as the gold standard

154

because the former is measured in the chest, where a cough effort becomes

155

effective. The measures for comparison were chosen by identifying the cough during

156

which each patient produced the highest PES. That value was then compared to the

157

pressures generated by the patient during the same maneuver at each of the other

158

sites.

159

A p value of <0.05 was considered statistically significant in the ICC analysis.

160

Statistical analysis was performed using IBM SPSS (IBM, Armonk, NY, USA) and

161

STATA (STATA Corp., College Station, TX, USA) software.

162 163

Results

164

Participants

165

Eleven patients initially consented to participate in the study, but one withdrew

166

consent as catheters were about to be inserted. Data from one patient were lost

167

because of technical problems. Thus, we analyzed data for nine patients. Their

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

168

characteristics are summarized in Table 1. No adverse events were observed during

169

the insertion of the catheters. Table 1 Demographic, anthropometric and functional data Age (yrs)

62  10

Gender (male/female)

6/3

ASA class (I/II/III)

0/9/0

Height (cm)

164  7

Weight (kg)

65  9

FEV1 (L/min)

3.2  0.9

FEV1 (% pred)

90  8

FVC (L)

2.7  0.7

FVC (% pred)

93  11

FEV1/FVC (%)

87  16

Data are presented as mean ± standard deviation or number of subjects. ASA = American Society of Anesthesiologists physical status classification system, FEV1 = forced expiratory volume in one second, FVC = forced vital capacity, %pred = percentage of the predicted value. 170 171 172 173 174 175

Test results The cough pressure curves for all sites were congruent. Figure 1 shows the pressure curves for patient number 4.

(Figure 1 should appear here)

The highest mean ± SD cough PES was 116  29 cmH2O. The mean cough

176

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

177

pressures recorded at the same time as the highest PES values were as follows: PGA, 120  35

178

cmH2O; PCV, 116  30 cmH2O; PBL, 125  36 cmH2O; and PREC, 116  34 cmH2O. Individual

179

measurements recorded for patients at each site are shown in Table 2.

(Table 2 should appear here)

180 181

The ICCs between these cough pressures overall showed excellent repeatability

182 183

between the three maneuvers performed by each patient (p <0.001) (Table 3).

184

Table 3 Repeatability of cough pressure measurement at different sites ICC

CI 95%

p value

PES

0.888

0.665 – 0.972

<0.001

PGA

0.905

0.730 – 0.976

<0.001

PCV

0.884

0.665 – 0.971

<0.001

PBL

0.906

0.718 – 0.976

<0.001

PREC

0.896

0.626 – 0.975

<0.001

ICC = intraclass correlation coefficient, CI = confidence interval, PES = esophageal pressure, PGA = gastric pressure, PCV = central venous pressure, PBL = bladder pressure, PREC = rectal pressure. 185 186

The mean (CI limits) differences between cough PES and measurements at other sites

187

were as follows: PGA, –4.2 (95% CI, –12.3, 3.9) cmH2O; PCV, 0.3 (95% CI, –5.2, 5.7) cmH2O;

188

PBL, –8.7 (95% CI, –17.3, –0.17.0) cmH2O; and PREC, –0.1 (95% CI, –8.2, 8.1) cmH2O.

189

Bland-Altman plots of these differences are shown in Figure 2. PCV and PREC were the

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

190

alternative-site pressures that showed the best agreement, with mean differences close to

191

zero and lower and upper CI limits that were about 5% and 7% of mean values,

192

respectively. The mean difference between PES and PBL was slightly larger, and both the

193

difference and the CI limits were negative values.

(Figure 2 should appear here)

194 195 196

The rectal catheter was the least unpleasant for all the patients, whereas the ones

197

introduced nasally into the esophagus and stomach were the most uncomfortable for seven

198

patients (four men and three women). The bladder catheter was the most uncomfortable

199

for two men.

200 201 202

Discussion This study demonstrates that cough pressure can be measured with central

203

venous or rectal catheters as alternatives to conventional esophageal balloon

204

catheters. Bladder catheters could also be used although recorded PBL values were

205

slightly higher than the gold-standard PES values.

206

The ICC analysis indicated excellent repeatability between measurements at the

207

same site, evidence of the precision of cough pressure measurements at each of the

208

sites. The Bland-Altman plots demonstrated very small mean differences between PES

209

and PGA, PCV and PREC. The plots therefore suggest the alternative measurements are

210

accurate. Thus, PCV or PREC would be valid candidates to choose as surrogates for PES.

211

The greater difference between PBL and PES, on the other hand, shows that pressure

212

behaves differently at the bladder. Furthermore, given that PBL was usually higher

213

than PES and both the mean difference in these two values and the CI limits were

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

214

negative, we can conclude that PBL was precise but less accurate than pressure

215

measurements at the other alternative sites. This slight but systematic difference

216

between PES and PBL would mean that the bladder catheter would be the last-choice

217

alternative to the esophageal catheter. PBL could nevertheless be useful in

218

hospitalized patients who already have a bladder catheter in place, so as to avoid

219

placing an additional one.

220

Although PGA has been used widely to reflect cough pressure in studies of

221

respiratory muscle strength [4-6, 17] and was measured at the same time as PES in

222

this study, we designated PES as the gold standard in the Bland-Altman analysis

223

because it is recorded in the chest, where cough effort takes place. Cough pressures

224

have fluctuated in previous studies of expiratory muscle strength measured with PES

225

or PGA [4, 6, 17-19] because the study populations varied. Higher cough pressures are

226

observed in young, male, and tall subjects as well as in chronic coughers. We

227

measured cough pressure in a specific surgical population, accounting for differences

228

between our results and previously reported values.

229

Our study was performed under conditions relevant to clinical situations.

230

Patients were in supine position, in which the pressure transducers were all at the

231

same approximate level, favoring reliable comparison between measurement sites.

232

Patients carrying central venous or Foley (bladder) catheters are usually confined to

233

a bed. The cough maneuver was performed from TLC in order to achieve a

234

standardized test measurement [4] and because it is usual to take a deep breath

235

before a cough [5]. Maximum levels of respiratory muscle strength and hence

236

pressure are expected from TLC [5, 20].

237

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

The practical implication of our study is that cough pressure can be measured

238

using the technique that best fits the clinical condition of an individual patient. A

239

central venous catheter would be the first choice if one has been inserted. A bladder

240

catheter could also be used provided the clinician bears in mind the small systematic

241

difference between PBL and PES discussed above. If no catheter has been inserted, a

242

good choice would be a rectal catheter, which our patients found to be the least

243

uncomfortable. Esophageal pressure remains the gold standard, but its main

244

disadvantage, that the insertion of a balloon catheter through the nose causes

245

discomfort [4], was confirmed by our patients. In addition, discomfort can cause

246

esophageal contractions that can impede correct measurement in a considerable

247

percentage of patients [7]. For these reasons, esophageal and gastric balloons

248

should probably be reserved for selected patients or volunteers under experimental

249

conditions.

250

One limitation of our study is that the results probably cannot be extrapolated

251

to patients with chronic cough, in whom voluntary cough pressure can be higher

252

than in healthy individuals [17]. In addition, the results possibly cannot be

253

extrapolated to scenarios in which cough is triggered by nerve stimulation [21] or to

254

patient types we excluded. Similar results might well be obtained in these scenarios,

255

but further studies would be needed to confirm that hypothesis.

256

Our results facilitate further investigation and patient management in many

257

settings. An important scenario is the postoperative period after abdominal or

258

thoracic surgery, where cough effort is reduced [1-3] and where patients are at risk

259

of respiratory complications [22].

260

261

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

262

Conclusions Pressure generated with a cough maneuver from TLC in supine position can be

263

measured in the esophagus, stomach, superior vena cava, or rectum indistinctly.

264

Bladder catheters could also be used, although the recorded pressures would usually

265

be slightly higher than PES. These results support assessing expiratory muscle

266

strength for clinical or research purposes without using an additional invasive

267

catheter in most hospitalized patients. If no invasive catheter has already been

268

placed for clinical purposes, a minimally invasive catheter can be chosen for

269

assessing cough pressure.

270 271

List of abbreviations

272 273

ASA: American Society of Anesthesiologists physical status classification system; CI:

274

confidence interval; FEV1: forced expiratory volume in one second; FVC: forced vital

275

capacity; ICC: Intraclass Correlation Coefficient; PCV: central venous pressure; PES:

276

esophageal pressure; PGA: gastric pressure; PREC: rectal pressure; PBL: bladder pressure; TLC:

277

total lung capacity.

278 279

Declarations

280

Ethics approval and consent to participate

281

This study was approved by our institutional review board (the clinical research ethics

282

committee of Parc de Salut Mar –CEIC-Parc de Salut Mar), reference number 031554. It

283

was also approved by the Spanish Agency for Medicines and Health Products (AEMPS),

284

reference number 040073.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

285

All patients signed an informed consent form before being enrolled the study.

286

Consent for publication

287

Not applicable

288

Availability of data and material

289

The datasets used and/or analyzed during the current study are available from the

290

corresponding author on reasonable request.

291

Competing interests

292

The authors declare that they have no competing interests

293

Funding

294

Supported by Spanish Health Ministry’s research fund (Fondo de Investigaciones

295

Sanitarias, reference FIS PI030127) and CIBERES, Instituto de Salud Carlos III

296

(ISCIII), Spain.

297

Authors' contributions

298

L.G.A contributed to all parts of the design, analysis and reporting, and conducted

299

the research protocol. L.G. proposed the initial aim of the study, analyzed data, and

300

wrote the manuscript. J.C.A. helped conduct the research protocol and collect data.

301

J.V. supervised data collection and analysis. J.G. advised and critically reviewed the

302

manuscript. All authors approved the final manuscript and guarantee its integrity.

303

Acknowledgments

304

We thank the nurses of the surgical area of Hospital del Mar, Barcelona, for

305

supporting our clinical management of patients and the staff of the Scientific &

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

306

Technical Services of the IMIM, Barcelona, for their cooperation. Mary Ellen Kerans

307

gave advice on English language expression in a late version of the manuscript.

308 309 310

References

311

1.

Med. 2003;168:10-48.

312 313

2.

Warner DO: Preventing postoperative pulmonary complications: the role of the anesthesiologist. Anesthesiology. 2000;92:1467-72.

314 315

Laghi F, Tobin MJ: Disorders of the respiratory muscles. Am J Respir Crit Care

3.

Colucci DB, Fiore JF, Jr., Paisani DM, Risso TT, Colucci M, Chiavegato LD,

316

Faresin SM: Cough impairment and risk of postoperative pulmonary

317

complications after open upper abdominal surgery. Respir Care. 2015;60:673-

318

8.

319

4.

Man WD, Kyroussis D, Fleming TA, Chetta A, Harraf F, Mustfa N, Rafferty GF,

320

Polkey MI, Moxham J: Cough gastric pressure and maximum expiratory mouth

321

pressure in humans. Am J Respir Crit Care Med. 2003;168:714-7.

322

5.

respiratory muscle testing. Am J Respir Crit Care Med. 2002;166:518-624.

323 324

American Thoracic Society/European Respiratory S: ATS/ERS Statement on

6.

Gallart L, Gea J, Aguar MC, Broquetas JM, Puig MM: Effects of interpleural

325

bupivacaine on respiratory muscle strength and pulmonary function.

326

Anesthesiology. 1995;83:48-55.

327

7.

Smith JA, Aliverti A, Quaranta M, McGuinness K, Kelsall A, Earis J, Calverley

328

PM: Chest wall dynamics during voluntary and induced cough in healthy

329

volunteers. J Physiol. 2012;590:563-74.

330

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

8.

Chieveley-Williams S, Dinner L, Puddicombe A, Field D, Lovell AT, Goldstone

331

JC: Central venous and bladder pressure reflect transdiaphragmatic pressure

332

during pressure support ventilation. Chest. 2002;121:533-8.

333

9.

Collee GG, Lomax DM, Ferguson C, Hanson GC: Bedside measurement of

334

intra-abdominal pressure (IAP) via an indwelling naso-gastric tube: clinical

335

validation of the technique. Intensive Care Med. 1993;19:478-80.

336

10.

pressure in various conditions. Eur J Surg. 1997;163:883-7.

337 338

11.

Malbrain ML: Different techniques to measure intra-abdominal pressure (IAP): time for a critical re-appraisal. Intensive Care Med. 2004;30:357-71.

339 340

Shafik A, El-Sharkawy A, Sharaf WM: Direct measurement of intra-abdominal

12.

Roca J, Sanchis J, Agusti-Vidal A, Segarra F, Navajas D, Rodriguez-Roisin R,

341

Casan P, Sans S: Spirometric reference values from a Mediterranean

342

population. Bull Eur Physiopathol Respir. 1986;22:217-24.

343

13.

catheterization. N Engl J Med. 2003;348:1123-33.

344 345

14.

Pittman JA, Ping JS, Mark JB: Arterial and central venous pressure monitoring. Int Anesthesiol Clin. 2004;42:13-30.

346 347

McGee DC, Gould MK: Preventing complications of central venous

15.

Iberti TJ, Lieber CE, Benjamin E: Determination of intra-abdominal pressure

348

using a transurethral bladder catheter: clinical validation of the technique.

349

Anesthesiology. 1989;70:47-50.

350

16.

two methods of clinical measurement. Lancet. 1986;1:307-10.

351 352 353

Bland JM, Altman DG: Statistical methods for assessing agreement between

17.

Lee KK, Ward K, Rafferty GF, Moxham J, Birring SS: The Intensity of Voluntary, Induced, and Spontaneous Cough. Chest. 2015;148:1259-67.

354

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

18.

1975;67:654-7.

355 356

Byrd RB, Burns JR: Cough dynamics in the post-thoracotomy state. Chest.

19.

Arora NS, Gal TJ: Cough dynamics during progressive expiratory muscle

357

weakness in healthy curarized subjects. J Appl Physiol Respir Environ Exerc

358

Physiol. 1981;51:494-8.

359

20.

1988;9:249-61.

360 361

21.

Man WD, Moxham J, Polkey MI: Magnetic stimulation for the measurement of respiratory and skeletal muscle function. Eur Respir J. 2004;24:846-60.

362 363

Rochester DF: Tests of respiratory muscle function. Clin Chest Med.

22.

Canet J, Gallart L, Gomar C, Paluzie G, Valles J, Castillo J, Sabate S, Mazo V,

364

Briones Z, Sanchis J: Prediction of postoperative pulmonary complications in a

365

population-based surgical cohort. Anesthesiology. 2010;113:1338-50.

366 367

Figure legends and Table 2

368

Fig 1. Waveforms at all five measurement sites. Congruent waveforms

369

recorded for patient No. 4 at all five measurement sites. PCV = central venous

370

pressure; PES = esophageal pressure; PGA = gastric pressure; PBL = bladder pressure;

371

PREC = rectal pressure.

372

Fig 2. Bland-Altman plots between PES and the alternative sites. Bland-

373

Altman plots showing agreement between cough pressures measured at the

374

esophagus (PES) and the alternative sites. Values are expressed in cmH2O. PCV =

375

central venous pressure; PES = esophageal pressure; PGA = gastric pressure; PBL =

376

bladder pressure; PREC = rectal pressure.

377

378

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

Table 2 Measurements of cough pressure at five sites Maneuver Patient No. 1

2

3

4

5

PES

PGA

PCV

PBL

PREC

1

85.3

97.4

97.6

95.9

87

2

84.6

85.2

93.8

92

82.7

3

83.2

95

90.9

95.4

88.9

1

58.2

52.9

65.8

55.4

51.3

2

77.3

78

79.2

83.1

74.6

3

73.8

56.7

72.5

59.6

55.1

1

132.8

128.8

127.9

141.1

114.5

2

137.7

132.5

144.4

153.6

121.5

3

147.9

146.2

143.8

160.8

135.2

1

81.7

82.1

82.3

84.2

81.2

2

85.5

89.2

95

90.4

88.9

3

104

93.2

101.9

95.1

92.1

1

74.6

70

66.6

78.2

69.3

2

91.9

90.1

85.3

91

89.4

3

91.3

83.1

91.2

100.6

82.6

No.

6 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 379 52 53 54 55 56 57 58 59 60 61 62 63 64 65

7

8

9

1

102.9

101.9

99.8

111.9

100.1

2

108.3

104.6

105.3

115.5

102.9

3

112.4

105.3

101.9

117.7

102.9

1

110.5

116.5

106.9

128.1

115.9

2

125.9

140.3

121.7

150.4

138.5

3

118.5

131.3

114.9

142

131

1

148.5

168.8

156.5

167.9

143.3

2

132.5

152.2

137.7

158

146.9

3

148.8

167.3

154

152.8

162.4

1

121.6

128.4

123.1

137.15

127.2

2

152.9

166.4

158.5

178.25

164.9

3

140.9

159.8

143.9

169.65

157.5

Values are in cmH2O. Bold-face values identify the maneuver that generated the highest PES. PES = esophageal pressure, PGA = gastric pressure, PCV = central venous pressure, PBL = bladder pressure, PREC = rectal pressure.

Figure 1

PCV

PES PGA PBL PREC

Click here to download Figure Aguilera Fig. 1.pptx

Figure 2

Click here to download Figure Aguilera Fig. 2.pptx



Measured pressures

Mean difference between measurements

95% IC