PURPOSE: To determine whether metabolic and hemodynamic parameters are "mathematically" coupled in rats submitted to portal triad occlusion following controlled hemorrhagic shock state. METHODS: Pearson's coefficient (r-value) analysis was performed. Differences considered significant at p  r > 0.50. RESULTS: It was observed that there is a direct proportional relationship to HCO3- with pCO2 (r = 0.66), base deficit (r = 0.87) and inverse with serum lactate (r = -0.54). pCO2 was directly associated with MAP (r = 0.51), and inversely with pH (r = -0.64). Hematocrit was directly associated with HR (r = 0.72) and CI (r = 0.76), and serum lactated was inversely associated with base deficit (r = -0.61). CONCLUSION: In rats submitted to Pringle's maneuver during 15 minutes following hemorrhagic shock state, there is a mathematical coupling with a very good correlation between several hemodynamic and metabolic variables.201222

Fontelles M.J.

Hirano E.S.

Mantovani M.

Morandin R.C.

Repositorio da Producao Cientifica e Intelectual da Unicamp

Fontelles MJ et al
22 - Acta Cirúrgica Brasileira - Vol 20 (1) 2005
5 - ORIGINAL ARTICLE
Investigating the relationship between hemodynamic and metabolic parameters
in portal triade occlusion following hemorrhagic shock1
Estudo da relação entre os parâmetros hemodinâmicos e metabólicos na oclusão da
tríade portal associada ao choque hemorrágico
Mauro José Fontelles2, Mario Mantovani3, Elcio Shiyoiti Hirano4, Rosana Celestina Morandin5
1. Article from Trauma Surgery Division of the Department of Surgery, Faculty of Medical Sciences, Unicamp, Campinas – Brazil.
2. Ph.D., Trauma Surgery. Professor of Human Anatomy, Universidade da Amazônia – Unama.
3. Ph.D., Titular Professor, Chief - Trauma Surgery, Department of Surgery, Faculty of Medical Sciences, Unicamp.
4. MSc., Trauma Surgery, Unicamp.
5. Ph.D., Biology, Unicamp.
ABSTRACT
Purpose: To determine whether metabolic and hemodynamic parameters are “mathematically” coupled in
rats submitted to portal triad occlusion following controlled hemorrhagic shock state. Methods: Pearson’s
coefficient (r-value) analysis was performed. Differences considered significant at p<0.05 and -0.50>r>0.50.
Results: It was observed that there is a direct proportional relationship to HCO3- with pCO2 (r=0.66), base
deficit (r=0.87) and inverse with serum lactate (r=-0.54). pCO2 was directly associated with MAP (r=0.51),
and inversely with pH (r=-0.64). Hematocrit was directly associated with HR (r=0.72) and CI (r=0.76), and
serum lactated was inversely associated with base deficit (r=-0.61). Conclusion: In rats submitted to Pringle’s
maneuver during 15 minutes following hemorrhagic shock state, there is a mathematical coupling with a very
good correlation between several hemodynamic and metabolic variables.
Key words: Pringle’s maneuve. Hepatic ischemia. Hemorrhagic shock.. Liver.
RESUMO
Objetivo: com a utilização de um modelo experimental, determinar se as alterações hemodinâmicas e
metabólicas estão “matematicamente” relacionadas em ratos submetidos a estado de choque hemorrágico
controlado seguido de isquemia hepática total. Métodos: O coeficiente de correlação de Pearson (valor r)
foi utilizado para determinação das fórmulas matemáticas. Diferenças foram consideradas significativas com
p<0,05 e -0,50>r>0.50. Resultados: Encontrou-se uma relação diretamente proporcional para o HCO3-
quando comparado com pCO2 (r=0,66) e com o déficit de base (r=0,87); e inversamente proporcional
quando comparado com o lactato sérico (r=-0,54). O pCO2 esteve diretamente relacionado com a PAM
(r=0,51) e inversamente com o pH (r=-0,64). O hematócrito esteve diretamente associado com a freqüência
cardíaca (r=0,72) e, também, com o índice cardíaco (r=0,70). O lactato sérico esteve inversamente associado
com o déficit de base (r=-0,61). Conclusão: Em ratos submetidos ao estado de choque hemorrágico
controlado, por 20 minutos, seguido de manobra de Pringle, por 15 minutos, diversas variáveis hemodinâmicas
e metabólicas estão matematicamente associadas.
Descritores: Manobra de Pringle. Isquemia hepática. Choque hemorrágico. Fígado.
Investigating the relationship
Acta Cirúrgica Brasileira - Vol 20 (1) 2005 - 23
Introduction
Trauma is the leading cause of death in patients
under 40 years of age. Death from abdominal trauma
is most commonly due to liver injury1,2. In these
patients, the temporary portal triad occlusion (PTO),
which is known as Pringle’s maneuver, is the standard
method for reducing the risk of massive hemorrhage
during liver surgery, but there is still controversy over
tolerance of the liver for ischemia3,4,5,6.
After a severe hepatic trauma, this maneuver
produces dramatic alterations in the systemic
hemodynamics during and immediately following
portal triad occlusion. The exact etiology of these
alterations remains unclear, but they have been linked
to ischemia of the liver, as well as alteration of the
splanchnic venous drainage resulting in intestinal
ischemia7,8.
Thus, the purpose of this study was to evaluate
the relationship between several metabolic and
hemodynamic parameters in rats submitted to
controlled hemorrhagic shock state associated to
portal triad occlusion.
Methods
All the procedures undertaken in this work
comply with the protocols approved in the Ethic
Commission on Animal Experiment of the Biologic
Institute of the Campinas University, Brazil.
Experiments were conducted in eight males
Wistar rats (UNICAMP, Campinas, SP) weight
ranging from 205-240g and eight weeks of age. The
rats were under intraperitoneal anesthesia (IP) with a
solution of cetamine cloridrate (80mg/kg – Cristália,
São Paulo) plus xilazine cloridrate (10mg/kg – Bayer,
São Paulo) and atropine (0,05mg/kg – Halex Star,
São Paulo). After the anesthesia was induced they
were placed in a supine position on a board with heat
controlled electrically. The right femoral artery was
exposed and a polyethylene catheter (PE 40),
previously heparinezed, placed on it for control of
the mean arterial blood pressure (MAP). Controlled
hemorrhagic shock was attained through bleeding until
the MAP reached 40mmHg, for 20 minutes, then,
volemic replacement with lactated Ringer’s solution
and blood (3:1) until the MAP reach 80mmHg was
performed. A laparotomy paying due care to avoid
excessive bleeding was made. The hepatoduodenal
ligament was identified and clamped (Pringle’s
maneuver) with soft arterial clamps for 15 minutes.
After clamp release a reperfusion period of 60 minutes
was performed. Figure 1 shows each phase of the
experiment as a function of time.
FIGURE 1 - Evolution of the experimental phases as a
function of time.
The following parameters were monitored
continuously: electrocardiogram (ECG), MAP, heart
rate (HR), respiratory rate (RR), and rectal
temperature (kept between 36°C - 38°C by external
heating). Blood gases (pO2, pCO2), electrolytes (Na
+,
K+), anion HCO3
-, Base Deficit (BD), serum lactate,
hematocrit (Ht), and pH/blood were performed via
arterial samples at baseline, after Pringles maneuver,
and after 30-60 minutes of hepatic reperfusion.
The cardiac index (CI) was calculated using
cardiac output (CO) and body surface area (BSA),
as suggested by Carbonell et al.9:
CI=CO/BSA (ml/min/cm2), Where:
CO=Systolic Volume/Time (ml/min) and BSA=12.54
x Body Weight (BW)0.6.
Statistical analysis was carried out during the
following periods: beginning of the reperfusion period,
and 30-60 minutes after. On the comparison analysis
between the hemodynamic and metabolic parameters
the Pearson’s coefficient (r-value) was used.
Differences considered significant at p<0.05, and –
0.50>r>0.50.
Results
The results show a very good correlation between
several hemodynamic and metabolic parameters during
the experiment. Figures 2 to 3 show hemodynamic and
metabolic variable as a function of time.
Fontelles MJ et al
24 - Acta Cirúrgica Brasileira - Vol 20 (1) 2005
The major finding of the current study was the
proportional relationship between different variables
in regarding HCO3
-, since pCO2 and base deficit are
in direct relation, and serum lactate is in inverse relation
to HCO3
- (Figure 3). A good correlation was also
obtained when pCO2 was compared with MAP and
pH arterial blood (Figure 4). Figure 5 shows
comparable data for hematocrit when associated with
heart rate and cardiac index, and Figure 6 illustrate
the inverse correlation between base deficit and serum
lactate.
FIGURE 2 - Evolution of the hemodynamic parameters. FIGURE 3 - Evolution of the metabolic parameters.
FIGURE 4 - Evolution of different parameters (pCO2, BD,
Lactate) with Bicarbonate, showing
corresponding equations, correlation
coefficients and significance level
FIGURE 5 - Evolution of different parameters (MAP, pH/
Blood) with pCO2, showing corresponding
equations, correlation coefficients and
significance level
Investigating the relationship
Acta Cirúrgica Brasileira - Vol 20 (1) 2005 - 25
Discussion
A Complex hepatic injury is associated to high
mortality rate, ranging from 40-80% and death can
occur due severe hemorrhage10. In liver surgery
following hepatic trauma, intraoperative bleeding is
an important prognostic indicator of both morbidity
and mortality, representing an independent risk factor
of postoperative, and temporary clamping of hepatic
pedicle is the standard method used to control
hemorrhage11,12.
Often referred to as the Pringle’s maneuver, the
PTO reduces the amount of hemorrhage from the liver
parenchyma while the liver injury is surgically repaired.
Frequently, this maneuver produces a profound effect
on systemic hemodynamics, since the portal vein
represents the principal venous drainage of the
splanchnic bed, and its occlusion leaves only
inadequate collateral pathways for the high volume of
blood delivered to the splanchnic drainage7,13. As
blood is reprised in the splanchnic bed, less blood
returns to the heart to be returned to the systemic
circulation, resulting in systemic shock state. On the
other hand, the mechanism of ischemic injury of the
liver following PTO has not yet been completely
elucidated13,14.
In the same manner, disturbance in tissue
perfusion and oxygenation are known to occurs during
hemorrhagic shock, and is necessary a good
understanding of its pathophysiological characteristics
for adequate treatment, especially when associated
with another aggravating condition, such as liver
ischemia15. Resuscitation from shock based on
invasive hemodynamic monitoring has been widely
used in hepatic trauma, since the early circulatory
response has been shown to be predictive of survival
in these patients16,17. Conventionally, tissue perfusion
has been evaluated from indirect parameters, such as
skin color and temperature, capillary refilling, urinary
output, altered mental status, or by measurement of
blood pressure, heart rate, and other signs and
symptoms indicative of circulatory shock18. More
specifically, tissue oxygenation has been inferred by
metabolic parameter due to serum lactate, base deficit,
pH arterial, and other blood measurements. However,
in literature, the relationship between these variables
has not been evaluated, and we hypothesize that these
parameters are mathematically coupled in rats
submitted to PTO following controlled hemorrhagic
shock state.
In our experimental model, PTO produces severe
alterations in systemic hemodynamics after few
minutes of occlusion with a decrease in the systemic
circulating blood volume. As a result, there was
FIGURE 6 - Evolution of different parameters (HR, CI) with
Hematocrit, showing corresponding
equations, correlation coefficients and
significance level
FIGURE 7 - Correlation of serum lactate values and BD,
showing corresponding equation, correlation
coefficient and significance level
Fontelles MJ et al
26 - Acta Cirúrgica Brasileira - Vol 20 (1) 2005
decreased venous return and an accentuated drop in
CO and MAP, triggering a reflexively
vasoconstriction. Despite intensive vasoconstriction,
MAP was not maintained and systemic hypotension
and bradycardia occurred likely as a parasympathetic
reflex19. As referred by Gonce et al.7, as CO and
MAP decrease in presence of severe
vasoconstriction, systemic tissue perfusion is impaired,
and the low CO combined with portal hypertension
produce profound splanchnic ischemia. After release
of the clamp a partial hemodynamics recovery was
detected with an improvement in CO, MAP and
metabolic parameters, however with a persistent
metabolic acidosis during the reperfusion period. The
direct relationships between pCO2 and BD with
HCO3
-, found in the experiment described here, could
be related to a compensatory mechanism to maintain
the corporal homeostasis since pH value remains
almost unaltered. In the same manner, a direct
relationship between hemodynamic and metabolic
variables also was observed, especially when
hematocrit or pCO2 values were related to MAP, CI
and HR.
In summary, the most relevant findings from this
study is that, in rats submitted to Pringle’s maneuver
following hemorrhagic shock, there is a mathematical
coupling with a very good correlation between several
hemodynamic and metabolic variables.
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Acknowledgments
The authors would like to thank Mr. Edilson Silva Jr.
for his helpful and review of the manuscript.
Investigating the relationship
Acta Cirúrgica Brasileira - Vol 20 (1) 2005 - 27
Correspondence:
Dr. Mauro José Fontelles
Rua Antônio Barreto, 983/1502
66055-050 Belém - Pará
Phone: (91)225-1850
mikefox@uol.com.br
How to cite this article:
Fontelles MJ, Mantovani M, Hirano ES, Morandin RC. Investigating the relationship between hemodynamic and metabolic
parameters in portal triade occlusion following hemorrhagic shock. Acta Cir Bras. [serial online] 2005 Jan-Feb;20(1).
Available from URL: http://www.scielo.br/acb
*Color figures available from www.scielo.br/acb
Conflict of interest: none
Financial source: none
Received: September 10, 2004
Review: November 25, 2004
Accepted: January 03, 2005


Investigating The Relationship Between Hemodynamic And Metabolic Parameters In Portal Triade Occlusion Following Hemorrhagic Shock.

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Investigating The Relationship Between Hemodynamic And Metabolic Parameters In Portal Triade Occlusion Following Hemorrhagic Shock.

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