Lung Function in Children Following Empyema Gregory J. Redding, MD; Lori Walund; Dean Walund, MD; Janet W. Jones, RPT; David C. Stamey, RRT; Ronald L. Gibson, MD, PhD \s=b\
Spirometry
was
performed
and
re-
sponse to exercise was measured in 15 children following recovery from empyema to evaluate the impact of pleural infection on subsequent lung function. Seven children underwent chest tube drainage; eight did not. The two groups were similar in age (mean\m=+-\SD, 6\m=+-\5 years), sex distribution, bacterial pathogen\p=m-\producingempyema, and age at follow-up evaluation (12\m=+-\5years). Only one child reported recurrent respiratory symptoms. No child had restrictive spirometric changes (total lung capacity, 80%; vital capacity, 80% predicted) but seven of 15 had a reduced forced expiratory volume in 1 second (0.50 fraction of inspired oxy¬ gen or >2 L/min, or arterial PC02 >50 mm Hg) were excluded to make the groups more comparable with respect to severity of the empyema at the time of hospital admission. Only one patient was excluded for this rea¬ son. Also excluded were four patients who developed empyema following thoracic sur¬ gery. Before patient contact, the study pro¬ tocol was reviewed and approved by the Hu¬ man Subjects Committee of the hospital. Fifteen of the remaining 21 subjects agreed to travel to Children's Hospital and Medical Center for follow-up pulmonary evaluation. The laboratory methods by which empyema was diagnosed in each enrolled patient are presented in Table 1. All children and/or their parents gave written consent for enroll¬ ment before study. Seven children who had undergone chest tube drainage at the onset of hospitalization and received parenteral antibiotics were designated as group 1. Group 2 included eight children who had re¬ ceived only parenteral antibiotics. The medical records of both groups were reviewed for age at time of empyema, sex, causative organism, duration of hospitaliza¬ tion and administration of parenteral antibi¬ otics, and duration of temperature greater than 38.5°C following initiation of antibiotic treatment. The decision to use chest tube drainage as a part of therapy was dictated by the clincial assessment and biases of the vari-
Features of Pleural Fluid in Children With
Table 1
Empyema*
— .
Patient No.
Group
Culture
CÍE
Gram's Stain
WBC
Count, x10»/L
PMN
1
7
+
2
+
..
+
0.83
.
-
+ +
5
+
6 7
+
...
57
0.59
+
+
+
171
+
+
39
0.98 0.77
+
+
254
1.00
...
Group 2 +
44
0.99
9
+
+
+
108
1.00
10
+
+
+
33
+
+
9
8
11 12
Group 1
Variable
1
3 4
Table 2.—Clinical Characteristics of Study Group at the Time of Empyema*
+
No. of patients Sex, M:F Age at time of empyema, y No. of thoracenteses
Organism Streptococcus pneumoniae Haemophilus influenzae
0.96
+
+
14
0.85
13
+
+
+
12
0.95
14
+
+
+
40
0.43
8
3:4
2:6
6.8 ±4.2 9
5.9 ±4.5 11
3
7
2
2
1
0
1
0
Staphylococcus aureus
Fusobacterium nucleatum
-
Group 2
7
Roentgenographic pleural thickness (n 9) =
15
+
*CIE indicates counterimmune electrophoresis for Haemophilus influenzae or Streptococcus pneumoniae; WBC, white blood cell; PMN, polymorphonuclear leukocytes; plus sign, positive; and minus sign,
negative.
attending physicians who managed this patients. Specific rationales for pleural drainage procedures were not well documented. Therefore, to determine retro¬ spectively whether one group was more se¬ verely ill than the other, average heart rate and respiratory rates as well as the maxi¬ mum temperature on the day of chest tube placement in group 1 were compared with ous
group of
the same indexes recorded for group 2 pa¬ tients on the third hospital day (the average day of hospitalization when chest tubes were placed in group 1 patients). In addition, the thickness of pleural fluid at the fifth rib on the chest roentgenogram obtained with the pa¬ tient in the lateral decubitus position at the time of admission was measured in millime¬ ters and as a percent of chest width to com¬ pensate for children of different sizes. Follow-up pulmonary function testing oc¬ curred when patients had been free of respi¬ ratory infection for at least 6 weeks. Before testing, each subject or parent reported from recall the number of lower respiratory tract infections per year that required visits to the physician's office or hospitalization subse¬ quent to the empyema. Each subject underwent spirometry at rest with use of a body plethysmograph (Gould Medical Corp, Dayton, Ohio, or Medi¬ cal Graphics Corp, St Paul, Minn). Vital ca¬ pacity and forced expiratory flow during the middle half of vital capacity (FEF26MH,) were expressed as a percentage of predicted norms.14 Forced expiratory volume in 1 sec¬ ond (FE V,) was expressed as both a percent¬ age of predicted and as a percentage of vital
capacity (FEV^VC). Body plethysmography was also used to measure absolute lung volumes, including total lung capacity (TLC), residual volume, residual volume-toTLC ratio, and functional residual capacity. These values, except for the residual volume-to-TLC ratio, were also expressed as percentages of published norms.14 All TLC values less than 80% predicted were consid¬ ered evidence of restrictive lung disease. Values of
FEV^eVC
less than 80% and/or FEFjä.,^ less than 75% predicted were con¬ sidered evidence of airway obstruction. The patients then rode an exercise bicycle ergometer (Quinton, Seattle, Wash) accord¬ ing to the James et al10 protocol for children. Cardiopulmonary indexes were measured with a heart rate monitor (Hewlett Packard, Waltham, Mass), exhaled gas concentrations with use of oxygen gas and carbon dioxide analyzers (Beckman OM-11 and Beckman LB2, respectively, Beckman Corp, Ana¬ heim, Calif), and a pneumotachygraph (Hew¬ lett-Packard No. 2). Analog signals were dig¬ itized, averaged, and stored on a personal computer every 20 seconds. Indices used to evaluate cardiopulmonary response to exer¬ cise included maximal tidal volume (Vtmax) and respiratory rate, minute ventilation, maximal heart rate, and maximum oxygen consumption (Vo2 max) during the last 30 seconds of each 2-minute interval of mea¬ sured work loads. Only indices measured during the greatest work load are presented and compared between the two groups. Max¬ imum voluntary ventilation (MVV) was cal¬ culated as FEV, times 35.16 Heart rate and
Downloaded From: http://archpedi.jamanetwork.com/ by a University of Iowa User on 06/20/2015
Millimeters % Chest width at HR chest tube
12±5 20 ± 13
20 ±5 21 ± 4
130 ±26
120±17
32±10
38±11
38.5 ±0.9 17±3
38.9 ±1.0 12±3
6±4
7±5
antibiotics, dt
17±4
10±4
Duration of chest tube in 6 of 7 patients, d
5± 1
placement or day 3 of hospitalization
RR at chest tube
placement or day 3 of hospitalization Tempma, at chest tube placement or day 3 of hospitalization Hospitalization, dt Fever after onset of parenteral antibiotics, d Parenteral
SD unless otherwise stated. *Values HR indicates heart rate; RR, respiratory rate; and Tempm„, maximum temperature. fSignificant difference (P
Spirometry
was
performed
and
re-
sponse to exercise was measured in 15 children following recovery from empyema to evaluate the impact of pleural infection on subsequent lung function. Seven children underwent chest tube drainage; eight did not. The two groups were similar in age (mean\m=+-\SD, 6\m=+-\5 years), sex distribution, bacterial pathogen\p=m-\producingempyema, and age at follow-up evaluation (12\m=+-\5years). Only one child reported recurrent respiratory symptoms. No child had restrictive spirometric changes (total lung capacity, 80%; vital capacity, 80% predicted) but seven of 15 had a reduced forced expiratory volume in 1 second (0.50 fraction of inspired oxy¬ gen or >2 L/min, or arterial PC02 >50 mm Hg) were excluded to make the groups more comparable with respect to severity of the empyema at the time of hospital admission. Only one patient was excluded for this rea¬ son. Also excluded were four patients who developed empyema following thoracic sur¬ gery. Before patient contact, the study pro¬ tocol was reviewed and approved by the Hu¬ man Subjects Committee of the hospital. Fifteen of the remaining 21 subjects agreed to travel to Children's Hospital and Medical Center for follow-up pulmonary evaluation. The laboratory methods by which empyema was diagnosed in each enrolled patient are presented in Table 1. All children and/or their parents gave written consent for enroll¬ ment before study. Seven children who had undergone chest tube drainage at the onset of hospitalization and received parenteral antibiotics were designated as group 1. Group 2 included eight children who had re¬ ceived only parenteral antibiotics. The medical records of both groups were reviewed for age at time of empyema, sex, causative organism, duration of hospitaliza¬ tion and administration of parenteral antibi¬ otics, and duration of temperature greater than 38.5°C following initiation of antibiotic treatment. The decision to use chest tube drainage as a part of therapy was dictated by the clincial assessment and biases of the vari-
Features of Pleural Fluid in Children With
Table 1
Empyema*
— .
Patient No.
Group
Culture
CÍE
Gram's Stain
WBC
Count, x10»/L
PMN
1
7
+
2
+
..
+
0.83
.
-
+ +
5
+
6 7
+
...
57
0.59
+
+
+
171
+
+
39
0.98 0.77
+
+
254
1.00
...
Group 2 +
44
0.99
9
+
+
+
108
1.00
10
+
+
+
33
+
+
9
8
11 12
Group 1
Variable
1
3 4
Table 2.—Clinical Characteristics of Study Group at the Time of Empyema*
+
No. of patients Sex, M:F Age at time of empyema, y No. of thoracenteses
Organism Streptococcus pneumoniae Haemophilus influenzae
0.96
+
+
14
0.85
13
+
+
+
12
0.95
14
+
+
+
40
0.43
8
3:4
2:6
6.8 ±4.2 9
5.9 ±4.5 11
3
7
2
2
1
0
1
0
Staphylococcus aureus
Fusobacterium nucleatum
-
Group 2
7
Roentgenographic pleural thickness (n 9) =
15
+
*CIE indicates counterimmune electrophoresis for Haemophilus influenzae or Streptococcus pneumoniae; WBC, white blood cell; PMN, polymorphonuclear leukocytes; plus sign, positive; and minus sign,
negative.
attending physicians who managed this patients. Specific rationales for pleural drainage procedures were not well documented. Therefore, to determine retro¬ spectively whether one group was more se¬ verely ill than the other, average heart rate and respiratory rates as well as the maxi¬ mum temperature on the day of chest tube placement in group 1 were compared with ous
group of
the same indexes recorded for group 2 pa¬ tients on the third hospital day (the average day of hospitalization when chest tubes were placed in group 1 patients). In addition, the thickness of pleural fluid at the fifth rib on the chest roentgenogram obtained with the pa¬ tient in the lateral decubitus position at the time of admission was measured in millime¬ ters and as a percent of chest width to com¬ pensate for children of different sizes. Follow-up pulmonary function testing oc¬ curred when patients had been free of respi¬ ratory infection for at least 6 weeks. Before testing, each subject or parent reported from recall the number of lower respiratory tract infections per year that required visits to the physician's office or hospitalization subse¬ quent to the empyema. Each subject underwent spirometry at rest with use of a body plethysmograph (Gould Medical Corp, Dayton, Ohio, or Medi¬ cal Graphics Corp, St Paul, Minn). Vital ca¬ pacity and forced expiratory flow during the middle half of vital capacity (FEF26MH,) were expressed as a percentage of predicted norms.14 Forced expiratory volume in 1 sec¬ ond (FE V,) was expressed as both a percent¬ age of predicted and as a percentage of vital
capacity (FEV^VC). Body plethysmography was also used to measure absolute lung volumes, including total lung capacity (TLC), residual volume, residual volume-toTLC ratio, and functional residual capacity. These values, except for the residual volume-to-TLC ratio, were also expressed as percentages of published norms.14 All TLC values less than 80% predicted were consid¬ ered evidence of restrictive lung disease. Values of
FEV^eVC
less than 80% and/or FEFjä.,^ less than 75% predicted were con¬ sidered evidence of airway obstruction. The patients then rode an exercise bicycle ergometer (Quinton, Seattle, Wash) accord¬ ing to the James et al10 protocol for children. Cardiopulmonary indexes were measured with a heart rate monitor (Hewlett Packard, Waltham, Mass), exhaled gas concentrations with use of oxygen gas and carbon dioxide analyzers (Beckman OM-11 and Beckman LB2, respectively, Beckman Corp, Ana¬ heim, Calif), and a pneumotachygraph (Hew¬ lett-Packard No. 2). Analog signals were dig¬ itized, averaged, and stored on a personal computer every 20 seconds. Indices used to evaluate cardiopulmonary response to exer¬ cise included maximal tidal volume (Vtmax) and respiratory rate, minute ventilation, maximal heart rate, and maximum oxygen consumption (Vo2 max) during the last 30 seconds of each 2-minute interval of mea¬ sured work loads. Only indices measured during the greatest work load are presented and compared between the two groups. Max¬ imum voluntary ventilation (MVV) was cal¬ culated as FEV, times 35.16 Heart rate and
Downloaded From: http://archpedi.jamanetwork.com/ by a University of Iowa User on 06/20/2015
Millimeters % Chest width at HR chest tube
12±5 20 ± 13
20 ±5 21 ± 4
130 ±26
120±17
32±10
38±11
38.5 ±0.9 17±3
38.9 ±1.0 12±3
6±4
7±5
antibiotics, dt
17±4
10±4
Duration of chest tube in 6 of 7 patients, d
5± 1
placement or day 3 of hospitalization
RR at chest tube
placement or day 3 of hospitalization Tempma, at chest tube placement or day 3 of hospitalization Hospitalization, dt Fever after onset of parenteral antibiotics, d Parenteral
SD unless otherwise stated. *Values HR indicates heart rate; RR, respiratory rate; and Tempm„, maximum temperature. fSignificant difference (P
