CARDIOVASCULAR JOURNAL OF AFRICA • Vol 22, No 3, May/June 2011
128
AFRICA
Isoflurane pre-treatment before cardiopulmonary bypass
alleviates neutrophil accumulation in dog lungs
GUI-ZHI DU, HONG GAO, JIN LIU, GUAN-SHENG WU, XIANG HE, XIANG-GANG ZENG, XUAN-YI HU,
XIN-HUA LI
Abstract
Objective:
This study investigated the effect of isoflurane pre-
treatment on cardiopulmonary bypass (CPB)-related lung
injury.
Methods:
Twelve dogs were randomly divided into two groups
of six each. In one group, 1.0 minimum alveolar concentra-
tion (MAC) of isoflurane was administered for 30 min before
CPB, while the control group received no anaesthetic. Both
groups then underwent 100 min of mild hypothermic CPB
with 60-min aortic cross clamping. Haemodynamic param-
eters, respiratory mechanics and alveolar arterial oxygen
difference (AaDO
2
) were measured during the experiment.
One hundred and fifty minutes after CPB, lung tissue
samples from the non-dependent and dependent portions of
the left and right lungs were harvested for polymorphonulear
leukocyte (PMNs) counts.
Results:
Following CPB, within the control group, pulmonary
vascular resistance (PVR) was significantly increased at 60,
120 and 180 min after declamping,AaDO
2
deteriorated at 180
min post-declamping, and dynamic lung compliance (DLC)
was reduced dramatically after declamping. Isoflurane pre-
treatment before CPB significantly reduced PVR compared
to the controls. AaDO
2
was impaired at 180 min after
declamping and DLC was decreased after declamping within
the isoflurane group. No differences inAaDO
2
and DLC were
found between the isoflurane and control groups. At 180 min
after declamping, the PMN count in both the non-dependent
and dependent regions of the isoflurane pre-treated lungs
was significantly lower than that of the controls.
Conclusions:
Our results suggest that 30-min pre-treatment
with 1.0 MAC isoflurane before CPB caused a reduction in
PMN accumulation in the dog lungs, inhibition of increases in
PVR, and it did not affectAaDO
2
in the early post-CPB stage.
Keywords:
cardiopulmonary bypass, lung injury, isoflurane, dog
Submitted 27/4/10, accepted 1/7/10
Published online 9/11/10
Cardiovasc J Afr
2011;
22
: 128–133
DOI: CVJ-21.041
The lungs are one of the most susceptible organs to ischaemia/
reperfusion (IR) injury and systemic inflammatory response
syndrome (SIRS) initiated during cardiopulmonary bypass
(CPB).
1
Laboratory and clinical investigations have demonstrat-
ed that accumulation of polymorphonuclear leukocytes (PMNs)
in the lungs plays a key role in the pathogenesis of CPB-related
lung injury, which leads to impairment of gas exchange, increase
in pulmonary vascular resistance (PVR) and decrease in pulmo-
nary compliance.
1-5
Volatile anaesthetics are commonly used during cardiac
surgery. Nevertheless the effects of inhaled anaesthetic agents
on lung injury remain controversial. Some studies showed that
volatile anaesthetics can enhance the sensitivity of pulmonary
artery endothelial cells to oxidation-mediated injury,
6
heighten
pulmonary alveolar capillary membrane permeability in rabbits
after aortic occlusion-perfusion,
7
and augment acute inflam-
matory response and leukocytic infiltration in acid-impaired
rat lungs,
8
indicating that volatile anaesthetics may potentially
exacerbate lung injury.
By contrast, in a mouse model of multiple organ dysfunction
syndrome, it was shown that halothane and isoflurane attenuated
lung inflammation and injury.
9
Liu and colleagues
10, 11
reported
the administration of isoflurane before ischaemia and during
reperfusion inhibited IR-induced isolated rabbit lung injury
and demonstrated that not only isoflurane but also sevoflurane
administered before ischaemia attenuated IR-induced injury in
isolated rat lungs. More recently, Reutershan
12
and Li
13
docu-
mented the protective pre-treatment effects by isoflurane against
endotoxin-induced lung injury in mouse and rat models.
In addition, the protective effects against IR injury by volatile
anaesthetics have been shown in the myocardium,
14
brain,
15
liver
16
and kidney.
17
These data suggest that inhaled anaesthetics may
not necessarily exacerbate lung injury after CPB. We therefore
used an adult mongrel dog model of CPB to verify the hypothesis
that pre-treatment of 30-min 1.0 minimum alveolar concentra-
tion (MAC) isoflurane before CPB would not aggravate lung
injury related to CPB during the early post-CPB stage.
Methods
All experimental procedures used in this investigation were
reviewed and approved by the Animal Care and Experimental
Department of Anesthesiology, West China Hospital,
Sichuan University, Chengdu 610041, Sichuan, China
GUI-ZHI DU, MM
JIN LIU, MD,
Department of Anesthesiology, the Affiliated Hospital of
Guiyang Medical College, Guiyang 550004, Guizhou, China
HONG GAO, MM,
XIANG-GANG ZENG, MB
Department of Anesthesiology, Guizhou Provincial Hospital,
Guiyang 550002, Guizhou, China
XIANG HE
Department of Cardiac Surgery, the Affiliated Hospital of
Guiyang Medical College, Guiyang 550004, Guizhou, China
GUAN-SHENG WU, MM
XUAN-YI HU, MM
Division of Public Health, Guiyang Medical College,
Guiyang 550004, Guizhou, China
XIN-HUA LI, MB
