Incentive Spirometry Performance

Incentive Spirometry Performance

Incentive Spirometry Performance* A Reliable Indicator of Pulmonary Function in the Early Postoperative Period After Lobectomy? Regine Bastin, PT; Jea...

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Incentive Spirometry Performance* A Reliable Indicator of Pulmonary Function in the Early Postoperative Period After Lobectomy? Regine Bastin, PT; Jean-Jacques Moraine, PT, PhD; Gizella Bardocsky, MD; Robert-Jean Kahn, MD; and Christian Melot, MD, PhD, MScBiostat

Objectives: The purpose of our study was to validate the incentive spirometry (IS) as a simple mean to follow pulmonary function at the bedside after lung surgery. Materials and methods: We studied prospectively 19 patients (16 men, 3 women; mean±SE age, 60±2.8 years) undergoing lobectomy for lung cancer. All the patients had an obstructive pattern with FEV /FVC below 75%. Lung volumes, including functional residual capacity (FRC) and residual volume (RV), measured using spirometry and the helium dilution technique, and IS were measured preoperatively and postoperatively at days 1, 2, 3, and 8, and at 2 months. Results: Our results showed that in the postoperative period after lung resection, IS performance was well correlated (R) during the first 8 postoperative days with vital capacity (VC) (R between 0.667 and 0.870) mainly due to the excellent correlation with the inspiratory reserve volume (IRV, R between 0.680 and 0.895) but was poorly correlated with expiratory reserve volume (R below 0.340), RV (R below 0.180), and FRC (R below 0.470). Conclusions: IS can be used as a simple mean to follow lung function, especially VC and IRV, in the postoperative period in spontaneously breathing patients. IS is noninvasive and can be performed repeatedly at the bedside in the intensive care setting. (CHEST 1997; 111:559-63) Abbreviations: ERV=expiratory reserve volume; FRC =functional r esidual capacity; IRV=inspiratory reserve volume; IS=incentive spirometry; RV =residual volume; VC=vital capacity; VT=tidal volume

L ung resection offers the best prospect of long-

term survival in patients with nonmetastatic bronchogenic carcinoma. 1 However, the frequent coexistence of chronic airflow limitation increases the risk of surgery because removal of lung tissue may grossly impair postoperative ventilatory function in such patients .2 Following thoracic surgery, pulmonary changes can lead to hypoxemia, atelectasis, pneumonia, and occasionally to respiratory failure. 3 In this situation, it seems appropriate to use physical therapy or mechanical aids or both methods that increase lung volume to reduce postoperative complications . The most popular mechanical maneuver has been incentive spirometry (IS ). 3 -9 IS has been shown to be at least as efficient as other methods (intermittent positive pressure breathing, deep breathing exercises).5-7 It is used extensively because it encourages *From the Intensive Care Department (Drs. Bastin, Moraine, Kahn , and Melot) and the Department of Anesthesiology (Dr. Bardocsky), Erasme Unive rsity Hospital, Brussels, Belgium. Manuscript received February 13, 1996; revision accepted October 3. Reprint requests: Dr. Bastin, Department of Intensive Care, Erasme University Hospital, Lennik Road, 808, B-1070 Brussels, Belgium

deep breathing and needs minimal superv1Slon. While the benefit of an increase in lung volumes in the postoperative period is appreciated, the mechanism underlying the possibly beneficial effect is poorly understood. Recently, Melendez et al4 showed that postoperative IS elicited diaphragmatic dysfunction as evidenced by reduced diaphragmatic motion, and possibly failed to provide expansion of dependent lung segments. The repercussion of abdominal 5-7 •10 or thoracic11·12 surgery on lung function has been investigated extensively, but reports including functional residual capacity (FRC ) and expiratory reserve volume (E RV) in the first postoperative week are scarce, although the degree of alteration in these two parameters from preoperative values appears to be related to postoperative pulmonary morbidity.lo Therefore, before and shortly after surgery, we evaluated the relationships between IS performance and lung spirometric measurements, including FRC, in patients undergoing lobectomy for bronchial carcinoma; our aim was to validate asimple means to follow pulmonary function at the bedside in the intensive care setting. Our results show that IS performance is well correlated with vital capacity (VC) mainly due to the CHEST I 111 I 3 I MARCH, 1997


excellent correlation with inspiratory reseiVe volume (IRV), but it is poorly correlated with ERV, residual volume (RV), and FRC.


Patients We studied prospectively 19 patients undergoing lobectomy for lung cancer. There were 16 men and 3 women, aged 43 to 72 years (60±2.8 years, mean±SE). All were considered to have technically rese ctable tumors according to clinical, radiographic, and bronchoscopic criteria.

Methods The pulmonary function studies ~·e re obtained by the patient using a mouthpiece, a noseclip, and a 9-L r sepirometer (SpiroJunior; E. Jaeger; Wuerzburg, Germany) with a helium meter (FRC-Test; E. Jaeger) constructed on a portable cart that was moved to the bedside. All measurements (including the FEV 1) except the FRC and RV were read directly off the kymograph paper. The FRC was calculated using the closed-circuit helium method in which 800 to 900 mL of 100% helium was added to the closed spiromete r circuit containing a fixed volume of room air. This mixture wascirculated constantly throughout the system b y an electric blower, and th e initial percent concentration of helium was read and recorded b efore the patient was allowed to breathe the mixture of gas in the spirometer. Beginning with the end of a normal expiration, the patient continued to breathe a t a normal tidal volume (VT) until a constant, final h elium concentration was obtained. This indicated equilibrium of helium concentration between the lungs and spiromete r. From these data, the FRC was calculated in a customary manner. IS was perform ed u sing avolumetric spirometer (D HD Coach; Diemolding H ealthcare Division; Canastota, NY). The patient was instructed b ythe physiotherapist to use the IS the day before the operating room procedure. Briefly, after a qui et expiration, the patient was encouraged to inhale slowly and as deeply as possible through th e mouthpiece of the IS device. Dming the inhalation, the patient was asked to maintain visually a blue marker b etween two arrows to keep the flow constant (measured around 520 mUs) . Inspiration moves the piston upward in a graduated c ylinde r (from 500 to 4,000 mL). The IS value used for correlation with pulmonary function tests w as the best of three consecutive IS maneuvers performed under the supervision of the physiotherapist during the daily c hest physiotherapy. Moreover, the patients were told that they should use the IS by themselves eve ty daytime hour postoperatively.

Protocol IS measurements were done in the morning and classic spirome tric measurements were done in the afternoon to avoid a time correlation between the two maneuvers. Measurements were performed preoperatively and postoperatively at days 1 , 2, 3, and 8 in the sitting position. Alate measurement was recorded after a mean of 2 months (range, 3 weeks to 6 months ). Statistical Analysis Evolution in time of VC, IRV, ERV, FRC, RV, FEV 1 , and IS was analyzed u sing an analysis of variance for repeated measures design. When the F ra tio of the analysis o f v raiance reached the


level of significance (p < 0.05), pairwise comparisons were made using modified t tests. Linear c orrelation between IS and VC, VT, ERV, IRV, RV, FRC, and FEV 1 were co mputed on a daily basis.


Patients' characteristics and extent of surgery are shown in Table l. All the patients had an obstructive pattern at the preoperative respiratory functional tests with an FEV/FVC below 75% (range, 41 to 73%). All the patients except one had continuous epidural analgesia with fentanyl. The remaining patient had an IV patient-controlled analgesia. Seventeen patients had no postoperative cardiopulmonary complications. Two patients, who had also a rib resection, developed subcutaneous emphysema due to bronchopulmona1y fistula. Owing to air leakage, FRC could not be measured in these two patients. One of them d eveloped a pneumonia and the other a h emothorax. Table 2summarizes the evolution of lung volumes postoperatively at day 1, 2, 3, and 8 and at month 2. Volumes were minimal at day 1 and increased slowly from day 2 to day 8. Improvement was recorded for all the variables behveen day 8 and month 2. Table 3 summarized the correlation benveen IS and lung volumes on a daily basis in the 19 patients during the first postoperative week and after stabilization. Late measurements were done in only a smaller subset of patients. A tight correlation was computed between IS and VC, IRV, and FEV 1 , respectively. A loose correlation was obseiVed beween IS and ERV, RV, and FRC, respectively. Figure l summarizes the results expressed in percent of preoperative values. VC decreases to 45%, 68%, and 76% at the first postoperative day, after 1 week, and after 2 months, respectively. FEV 1 was reduced to 53%, 73%, and 82% at the first postoperative day, after l week, and after 2 months, respectively. However, the ratio FEV 1NC remains constant RV was proportionally less reduced: 76% at the first day, 80% at 1 week, and 83% at 2 months. FRC was r educed to 66% at the first postoperative day, 76% after 1 week, and 82% at 2 months. IS volume reduction follows the same pattern and amplitude as VC and FEV 1 .


Our results show that IS performance is tightly correlated with VC , especially with IRV, and with FEV 1 in the postoperative period after lobectomy. A loose correlation was obseiVed among IS and RV and FRC. The etiology of postoperative respiratory compliClinical Investigations

Table !-Characteristics of Patients and Type of Surgery Patient No./ Sex/Age, yr l/FI59 2/M/70 31M/72 4/MI63 51MI53 61MI47 71MI60 81FI43 91MI66 101MI67 111MI64 l2/MI68 131MI69 14/MI61 151FI61 161MI65 171MI63 lSIM/72 191MI42

Pulmonary Volumes Weight, kg

Height, em

VC,% Pred

FEV 1 ,% Pred

FRC,% Pred



66 86 60 50 78 96 102 71 65 74 57 61 72 62 80 75 89 78 62

163 167 165 162 185 179 175 167 175 180 178 171 173 160 161 177 171 168 179

75 115 100 90 86 87 79 113 94 88 78 120 100 106 103 104 79 85 84

55 87 93 73 86 80 52 97 80 67 52 106 88 93 92 57 59 59 68

134 128 92 165 115 100 170 142 146 180 201 173 118 138 129 168 153 151 123

59 52 66 61 67 72 50 72 63 57 50 65 66 67 73 41 56 51 63


*LU L=left upper lobe lobectomy; LLL=left lower lobe lobectomy; RUL=right upper lobe lobectomy; RML=right middle lobe lobectomy; RLL=right lower lobe lobectomy.

cations is presumed to be a decrease in lung volumes. Ali and colleagues 13 studied the effects of various types of surgery on lung volumes. However, they showed that the most marked decrease in FRC occurred after upper abdominal operations, not thoracotomy. Our patients were characterized by a 55% decrease in VC concomitant with a 34% decrease in FRC. These figures recorded in patients after removal of a pulmonary lobe are similar to those reported by Meyers and colleagues 10 after abdominal surgery, indicating a functional impairment less pronounced than after abdominal surgery with no amputation of lung parenchyma. All the studies support the conclusion that trunk surgery restricts motion of the rib cage and diaphragm, which leads to an increase in alveolar collapse and, in the extreme, to lobar atelectasis. Bendixen and colleagues 14 studied the pattern of resting normal subjects and found that

they sigh an average of 8 to 10 times/min when they are in semirecumbent position in bed. In a subsequent postoperative study of patients, they showed that morphine analgesia decreased the number of sighs without increasing the depth of voluntary tidal ventilation. 15 These studies provide the basis for our current concepts about the etiology of postoperative pulmonary complications. Pain and muscle spasm impair the chest wall function and decrease lung volume, so that at FRC, significant portions of lung volume are below closing volume.l 6 In the elderly, in whom closing volume is large, and in the obese, in whom FRC is small, a greater portion of the lung is below closing volume. The increased amount of lung below closing volume and the failure to sigh or to take deep breaths increases the likelihood of alveolar collapse. The inhibition of chest wall motion by pain also dimin-

Table 2-Lung Volume Changes in 19 Patients After Lobectomy* Preoperative VC , mL IRV, mL ERV, mL F RC, mL RV, mL FEV1 , mL IS, mL

3,236:!: 166 1,563:!: 150 782:!:142 3,607:!:289 2,875:!:227 1,901:!:113 2,642:!:140

Day 1 11

1,476 :!: 143 11 601:!:90 11 239 :!:49 2,304:!:175 11 1,998:!: 131 11 11 954:!:75 1,258 :!: 156 11

Day 2

Day 3


2 mo

1,637:!:139 1 661 :!:85 1 314:!:67 1 2,339:!:231 1 2,089:!:185 1 939:!:53 1 1,495 :!: 160 1

1,814:!: 131 1 687:!:80 1 375:!:63 1 2,348 :!: 243 1 2,051 :!:202 1 11 1,111:!:72 1,575 :!: 133 1

2,197:!: 139 1 994:!: 121 11 512:!:79 1 2,774:!:254' 2,298:!: 186 1 1,355:!:97 11 1,997:!:216 1

2,619:!:284 11 984:!:185 1 11 802:!:94 3,231:!:397 11 2,403:!:422 1 1 1,632:!: 164 t 2,333:!:229 1

*Values are expressed in mean:!:SE. 1 p < 0.05 from previous column. 1p < 0.05 fi·om preope rative value. CHEST I 111 I 3 I MARCH, 1997


Table 3-Correlation Between IS Measurements and Pulmonary Volumes* Correlation Coefficient Between IS and


Day 1

Day 2

Day 3

Day 8

::!:2 mo

0.680 n = 19 p< O.Ol 0.105 n = 19 p =N S - 0.029 n = 19 p=NS 0.728 n = 19 p< 0.001 0.054 n= 18 p = NS 0.055 n = 18 p =NS 0.582 n= 19 p < 0.01

0.697 n=19 p< O.OOl 0.019 n=18 p=NS 0.331 n=l8 p=NS 0.710 n=l8 p< 0.001 0.104 n = l6 p=NS 0.463 n=17 p< 0.05 0.470 n=19 p< 0.05

0.667 n= 19 p < 0.01 0.313 n=19 p=NS 0.210 n=19 p=NS 0.698 n= l9 p< O.OOI 0.148 n=16 p=NS 0.170 n= 16 p=NS 0.299 n= l9 p=NS

0.754 n=19 p<0.001 0.498 n=19 p<0.05 0.072 n=l9 p=NS 0.768 n=l9 p<0.001 0.174 n=16 p=NS 0.182 n=16 p=NS 0.497 n=19 p<0.05

0.870 n = l7 p< 0.001 0.486 n=17 p< 0.05 0.033 n=17 p =NS 0.680 n=l7 p<0.01 0.175 n=l5 p =NS 0.186 n= 15 p = NS 0.553 n=17 p< 0.05

0.852 n= 10 p
vc VT






*n is the number of available meas ures among th e 19 patients.

S= not significant.

ishes cough. Therefore, from a theoretical standpoint, IS exercises could be a simple means to substitute these impaired mechanisms in the early postoperative period. However, coaching the patient to maximally inflate the lungs was as effective as IS when delivered at similar intervals. 8

A major goal of postoperative respiratory therapy is to increase FRC. Continuous airway pressure can accomplish this by causing an increase in expiratory transpulmonary pressure. 17 Indeed, the diminished FRC appears to be related to postoperative pulmonary morbidity. 13 •18 ·19 In keeping with this therapeutic goal,






90 ./









--- --


...... ····················

.... ··






Day 1 Day 2 Day 3 Preop


FIGURE l. Relative changes in pulmonary volumes, FEV 1 , and IS in patients aft er ol bectomy for bronchial carcinoma.


Clinical Investigations

continuous positive airway pressure therapy restores FRC more quickly than IS after upper abdominal surgery.8 In our patients, IS is poorly correlated with FRC or RV and cannot be used to follow FRC changes at the bedside in the postoperative period. Because the result of failure to sigh and cough is atelectasis with increased intrapulmonary shunt, measurement of arterial oxygenation has been used increasingly as a measure of atelectasis. After laparotomy or thoracotomy, patients without complications develop an intrapulmonary shunt fraction of 10% .2°.2 1 In our patients, ERV decreased dramatically in the postoperative period, reaching zero in some patients, resulting in a closing volume greater than FRC, leading to atelectasis and impaired gas exchange. It would be of interest to follow these indices (ERV and FRC) in postoperative patients . Our results show that IS performance being loosely correlated with ERV and FRC, it is not reliable to follow these indices. In our patients, FEV 1 is also tightly correlated with IS . In fact, as the FEV 1NC ratio did not change throughout the follow-up period, this correlation is the result of the correlation with VC. Meyers and colleagues 10 reported similar findings after upper abdominal surgery. Owing to the functional loss in pulmonary volume in addition to the anatomic deficit, first postoperative days are crucial for these patients and any respiratory deterioration must be detected early. Therefore, a simple bedside evaluation of lung volumes by recording IS performance can be recommended. Shapiro et al 22 claimed that a sudden decrease in the performances of the IS maneuver appears 12 to 24 h before the clinical evidence of a pulmonary complication. They based this assertion on clinical experience and not on experimental data. In our series, two patients presented a dramatic diminution (>500 mL) of their IS performances. In one patient, IV patient-controlled analgesia was stopped 12 h before the measurements . The transient deterioration in lung function was corrected rapidly by administration of opiates. The second patient showed deterioration in his performances on day 3, 24 h prior to clinical and radiologic evidence of pneumonia. These two case reports confirm the assertion of Shapiro et al 22 that IS performance during the postoperative period allows early detection in pulmonary function. In summary, IS can be used as a simple mean to follow lung function , especially VC and IRV, at the bedside in the postoperative pe1iod in patients breathing spontaneously. IS is noninvasive and can be performed repeatedly at the bedside in the intensive care setting. A sudden decrease in the IS performances could be used as a warning of pulmonary deterioration. This point deserves further investigation.

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