Cardiovascular Journal of Africa: Vol 30 No 6 (November/December 2019)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 30, No 6, November/December 2019 338 AFRICA
deviation (SD). Data were tested with the Kolmogorov–Smirnov
test for normal distribution. Non-parametric data of the groups
were tested with the chi-squared test and parametric data were
tested with the independent samples t-test; p-values < 0.05 were
considered statistically significant.
Results
The main characteristics of the patients are presented in Table
2. Two groups were matched for all the demographic data
except pre-operative left ventricular ejection fraction (LVEF)
(significantly lower in group 1). Table 3 presents the postoperative
data of the two groups. The mean ± SD of MVS, pH, stay in
ICU, time in hospital and drainage amount were similar between
the two groups. The groups included similar percentages of
patients with PMV, number of grafts, postoperative revision,
postoperative atrial fibrillation and mortality rate.
Two patients in group 1 and two in group 2 were re-intubated
because of hypercapnia and hypoxia in arterial blood gas
analysis. The two patients in group 2 could not be weaned from
MVS because extubation criteria could not be achieved. One
patient (2.4%) in group 1 could not be weaned from MVS for
240 hours and a tracheostomy cannula was placed. The patient
died in the ICU due to cardiac failure. Another patient (0.3%) in
group 2 needed MVS for 52 hours but he survived.
All patients with postoperative atrial fibrillation were
administered amiodarone at a dose of 150 mg intravenous
infusion over 10 minutes, then 0.5 to 1 mg/min infusion for
24 hours. The cardiac rhythm was converted to normal sinus
rhythm in three (7.1%) patients in group 1 and four (1.2%) in
group 2. Atrial fibrillation persisted in three (0.9%) patients
despite the amiodarone therapy in group 2. These patients
received oral amiodarone 2 × 200 mg tablets daily after three
days of intravenous infusion and were discharged with oral
anticoagulation.
All patients undergoing postoperative revision for bleeding
were not extubated until the surgical intervention and the mean
MVS time for these patients was 154 ± 256.35 hours (range from
four to 450 hours). Postoperative properties of the patients are
presented in Table 3.
Discussion
The results of this study suggest that pulmonary function in
COPD patients undergoing CABG surgery with ONBHCAB
was not significantly affected by CPB. The incidence of COPD
in patients undergoing CABG surgery has been reported to
be as high as 26.1% and the risk of postoperative and long-
term morbidity and mortality increases with increasing age.18-20
Adabag et al.21 evaluated the results of 1 169 COPD patients
undergoing CABG surgery and reported that the mortality risk
was significantly higher in patients with moderate or severe
COPD. However, Rosenthal et al.22 reported no significant
difference among in-hospital mortality rates of patients with
or without co-morbidities, including COPD. Manganas et al.6
reported that the mortality rate after CABG surgery was not
affected by the presence or severity of COPD. In our study, the
mortality rates were 4.76% in group 1 and 1.50% in group 2, but
the difference was not statistically significant (p = 0.081).
The mean LVEF of group 1 was significantly lower than that
of group 2 (32 ± 5 vs 52 ± 7%, p < 0.001). This was to be expected
Table 2. Demographic data of the patients
Variables
Group 1
(n = 42)
Group 2
(n = 333) p-value*
Age, years (mean ± SD) 60.98 ± 9.98 61.50 ± 9.13 0.390α
Male, n (%) 40 (95.2) 293 (88.0) 0.161
Pre-operative EF, % (mean ± SD) 32 ± 5 52 ± 7 < 0.001
COPD GOLD class
I, n (%) 15 (35.7) 96 (28.8) 0.068
II, n (%) 22 (52.3) 207 (62.1) 0.359
III, n (%) 5 (12.0) 30 (9.1) 0.092
Diabetes mellitus, n (%) 26 (61.9) 168 (50.5) 0.162
Tobacco smoking
Active, n (%) 5 (13.1) 59 (22.3) 0.432μ
Passive, n (%) 26 (83.9) 206 (77.7)
Hypertension, n (%) 19 (45.2) 162 (48.6) 0.677
Hyperlipidaemia, n (%) 3 (7.1) 13 (3.9) 0.328
Thyroid gland dysfunction, n (%) 1 (2.4) 11 (3.3) 0.749
Chronic kidney disease, n (%) 3 (7.1) 12 (3.6) 0.271
Peripheral artery disease, n (%) 0 (0.0) 3 (0.9) 0.537
EF: ejection fraction; COPD: chronic obstructive pulmonary disease; GOLD:
Global Initiative for Chronic Obstructive Lung Disease study.
*Mann–Whitney U-test was used to calculate the p-values as the data were non-
normally distributed.
αThe t-test was used to calculate the p-value [ t (50.051 = –0.344, p = 0.731, 95%
CI: –3.492, 2.453)].
μChi-squared test was used to calculate the p-value [χ2(1) = 0.616, p = 0.432].
Table 3. Postoperative data
Variables
Group 1
(n = 42)
Group 2
(n = 333) p-valueα
MVS time, hours (mean ± SD) 13.52 ± 39.97 7.81 ± 30.17 0.434
PMV*, n (%) 2 (4.76) 4 (1.20) 0.083
Arterial pH (mean ± SD) 7.41 ± 2.08 7.43 ± 3.11 0.287
ICU stay time, hours (mean
± SD) 19.26 ± 19.39 18.19 ± 31.67 0.464
HOS time, days (mean ± SD) 4.93 ± 2.09 4.71 ± 1.62 0.559
Drainage amount, ml (mean
± SD) 698.81 ± 162.48 682.28 ± 159.21 0.560
LIMA graft, n (%) 36 (85.72) 297 (89.24) 0.987
SVG number
One SVG, n (%) 19 (45.24) 139 (41.74)
Two SVGs, n (%) 16 (38.10) 127 (38.14)
Three SVGs, n (%) 5 (11.90) 31 (9.31) 0.449μ
Four SVGs, n (%) 1 (2.38) 4 (1.20)
Inotropic support
One intoropic agent, n (%) 4 (9.52) 55 (16.52) 0.005β
More than one intoropic
agent, n (%)
7 (16.67) 15 (4.50)
IABP, n (%) 6 (14.29) 11 (3.30) < 0.001
Postoperative revision, n (%) 0 (.00) 3 (0.90) 0.537
Postoperative atrial fibrillation,
n (%) 3 (7.12) 7 (2.14) 0.056
Exitus**, n (%) 2 (4.76) 5 (1.50) 0.142
MVS: Mechanical ventilatory support; ICU: intensive care unit; HOS: hospital
stay; LIMA: left internal mammary artery; SVG: saphenous vein graft; IABP:
intra-aortic balloon pump; PMV: prolonged mechanical ventilation.
*Mean PMV times of groups 1 and 2 were 180 ± 84.85 h (range 120–240 h) and
241 ± 164 h (range 48–450) respectively (p = 0.643).
**The mortality rates of the groups were as follows: 4.8% (two patients) in
group 1 and 1.5% (five patients) in group 2 (p = 0.142).
αMann–Whitney U-test was used to calculate the p-values as the data were non-
normally distributed.
μChi-squared test was used to calculate the p-value [χ2(4) = 3.694, p = 0.449].
βChi-squared test was used to calculate the p-value [χ2(2) = 10.690, p = 0.005,
Cramer’s V = 0.169].