Intraoperative Management:
The Fluid and Monitoring Controversies
Presentation outline:
1. List the controversies of fluid management in patients undergoing thoracic
surgery
2. Explain the impact of fluid management strategies on outcome in thoracic
surgery patients
3. Describe different monitoring and fluid regimen strategies.
Summary:
Pulmonary complications post lung resection surgery remain a prime
cause of mortality and present a spectrum of disease processes ranging from
mild complications, such as atelectasis and pneumonia, to the more severe
presentations of acute lung injury (ALI) and adult respiratory distress syndrome
(ARDS). The incidence of ALI and ARDS varies according to the extent of
resection with pneumonectomy carrying the highest incidence of 3-10%
compared to 2-5 % for lesser resections and a mortality rate of up to 70%.
Although the pathogenesis of this complication is unclear, several mechanisms
have been suggested including; an increase in pulmonary capillary hydrostatic
pressure which results from the combined effect of lung resection and positive
fluid balance, alveolar injury during one lung ventilation, pulmonary hypertension,
impaired lymphatic drainage, or an increase in the capillary permeability as
manifested by the high protein content in post-pneumonectomy pulmonary
edema. Post lung resection ALI is differentiated from pulmonary edema
secondary to heart failure by the presence of a normal functioning heart and low
pulmonary capillary wedge pressure.
The volume of intravenous fluids administered has attracted much
attention. Concern that intravenous fluids may exacerbate or even cause
pulmonary complications has led to the widespread adoption of perioperative
restriction of fluids for thoracic surgical patients. Restrictive fluid management
incurs risks such as a hypovolemic state with impaired tissue perfusion, which
may result in organ dysfunction and in particular postoperative acute kidney
injury (AKI). The risk of AKI has been underappreciated until recently. Data now
show that the risk of AKI post lung resection surgery varies between 6 and 24%
with a mortality rate from 0-19%.
For decades, the debate over the adequate fluid management during lung
resection surgery has not been settled. Over the last decade, several factors
developed questioning the direct relationship between excess fluid intake
resulting in an increase in capillary hydrostatic pressure and development of ALI
post lung resection. The new model of capillary glycocalyx and its impact on the
Starling forces added to the complexity of the problem. Also, the model of "baby
lung" proposed and consequently the beneficiary effect of protective lung
ventilation added to the suspicion that the problem is multifactorial rather than a
simple cause. This complexity of fluid management calls for more rigorous
methods of monitoring of fluid therapy in the intraoperative and postoperative
courses targeting normovolemia. Different variables have been studied aiming to
achieve this normovolemia status and include cardiac index, stroke volume
variation and extravascular lung water with variable results.
The aim of this presentation is to highlight the impact of fluid management
strategies on outcome in thoracic surgery patients and the various methods of
monitoring to achieve this safe fluid management status.
Further Readings:
1. Parquin, F., et al., Post-pneumonectomy pulmonary edema: analysis and
risk factors. Eur J Cardiothorac Surg, 1996. 10(11): p. 929-32.
2. Licker, M., et al., Risk factors for acute lung injury after thoracic surgery for
lung cancer. Anesth Analg, 2003. 97(6): p. 1558-65.
3. Alam, N., et al., Incidence and risk factors for lung injury after lung cancer
resection. Ann Thorac Surg, 2007. 84(4): p. 1085-91.
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pneumonectomy for lung cancer. Interact Cardiovasc Thorac Surg, 2010.
10(6): p. 936-9.
5. Ishikawa, S., D.E. Griesdale, and J. Lohser, Acute kidney injury after lung
resection surgery: incidence and perioperative risk factors. Anesth Analg,
2012. 114(6): p. 1256-62
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incidence, risk factors, and significance. Ann Thorac Surg, 1994. 58(2): p.
524-8.
7. Licker, M., et al., Risk factors of acute kidney injury according to RIFLE
criteria after lung cancer surgery. Ann Thorac Surg, 2011. 91(3): p. 844-50
8. Licker, M., et al., Impact of intraoperative lung-protective interventions in
patients undergoing lung cancer surgery. Crit Care, 2009. 13(2): p. R41
9. Dull, R.O., et al., Lung heparan sulfates modulate K(fc) during increased
vascular pressure: evidence for glycocalyx-mediated
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p. L816-28.
10. Tarbell, J.M., Shear stress and the endothelial transport barrier.
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12. Assaad S, Popescu W, Perrino A. Fluid management in thoracic surgery.
Curr Opin Anaesthesiol. 2013 Feb; 26(1): 31-9.