ACA App
Annals of Cardiac Anaesthesia Annals of Cardiac Anaesthesia Annals of Cardiac Anaesthesia
Home | About us | Editorial Board | Search | Ahead of print | Current Issue | Archives | Submission | Subscribe | Advertise | Contact | Login 
Users online: 617 Small font size Default font size Increase font size Print this article Email this article Bookmark this page
 


 

 
     
    Advanced search
 

 
 
     
  
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Email Alert *
    Add to My List *
* Registration required (free)  


    Abstract
   Introduction
   Conclusion
    References
    Article Figures
    Article Tables

 Article Access Statistics
    Viewed937    
    Printed13    
    Emailed0    
    PDF Downloaded158    
    Comments [Add]    

Recommend this journal

 


 
Table of Contents
ORIGINAL ARTICLE  
Year : 2016  |  Volume : 19  |  Issue : 2  |  Page : 240-244
Tricks, tips, and literature review on the adapted vaporize system to deliver volatile agents during cardiopulmonary bypass


1 Department of Surgery and Anesthesia, Dante Pazzanese Institute of Cardiology, São Paulo, Italy
2 Department of Anesthesia and Intensive Care, IRCCS San Raffaele Scientific Institute, Milan, Italy
3 Department of Anesthesia and Intensive Care, IRCCS San Raffaele Scientific Institute; Department of Anesthesia and Intensive Care, Vita-Salute San Raffaele University, Milan, Italy

Click here for correspondence address and email

Date of Submission01-Oct-2015
Date of Acceptance25-Feb-2016
Date of Web Publication1-Apr-2016
 

   Abstract 

Background: Recently, evidence of cardio-protection and reduction in mortality due to the use of volatile agents during cardiac surgery led to an increase in their use during cardiopulmonary bypass (CPB). These findings seem to be enhanced when the volatile agents are used during all the surgical procedure, including the CPB period. Aims: Since the administration of volatile agents through CPB can be beneficial to the patients, we decided to review the use of volatile agents vaporized in the CPB circuit and to summarize some tricks and tips of this technique using our 10-year experience of Brazilian and Italian centers with a large volume of cardiac surgeries. Study Setting: Hospital. Methods: A literature review. Results: During the use of the volatile agents in CPB, it is very important to analyze all gases that come in and go out of the membrane oxygenators. The proper monitoring of inhaled and exhaled fraction of the gas allows not only monitoring of anesthesia level, but also the detection of possible leakage in the circuit. Any volatile agent in the membrane oxygenator is supposed to pollute the operating theater. This is the major reason why proper scavenging systems are always necessary when this technique is used. Conclusion: While waiting for industry upgrades, we recommend that volatile agents should be used during CPB only by skilled perfusionists and physicians with the aim to reduce postoperative morbidity and mortality.

Keywords: Anesthesia; Cardiac surgery; Cardiopulmonary bypass; Sevoflurane; Volatile anesthetic

How to cite this article:
Nigro Neto C, De Simone F, Cassara L, Dos Santos Silva CG, Maranhão Cardoso TA, Carco F, Zangrillo A, Landoni G. Tricks, tips, and literature review on the adapted vaporize system to deliver volatile agents during cardiopulmonary bypass. Ann Card Anaesth 2016;19:240-4

How to cite this URL:
Nigro Neto C, De Simone F, Cassara L, Dos Santos Silva CG, Maranhão Cardoso TA, Carco F, Zangrillo A, Landoni G. Tricks, tips, and literature review on the adapted vaporize system to deliver volatile agents during cardiopulmonary bypass. Ann Card Anaesth [serial online] 2016 [cited 2019 Oct 16];19:240-4. Available from: http://www.annals.in/text.asp?2016/19/2/240/179592



   Introduction Top


The use of volatile anesthetic agents during cardiopulmonary bypass (CPB) was described for the 1 st time about 40 years ago. [1] Originally, volatile agents were vaporized and administered in the early-generation bubble oxygenators. Today, most cardiac surgery interventions are performed with standard membrane oxygenators. Unfortunately, the newest CPB machines are not equipped routinely for the use of these anesthetic agents, and this means that we still need to adapt anesthetic vaporizers in the bypass circuit.

Some studies showed an evidence of cardioprotection and reduction in mortality due to the use of volatile agents during cardiac surgery. [2],[3],[4],[5],[6] These findings seems to be enhanced when the volatile agents are used during all the surgical procedure, including the period of CPB. [7]

Since the administration of volatile agents through CPB can be beneficial to the patients, we decided to review the use of volatile agents vaporized in the CPB circuit and to summarize some tricks and tips of this technique in our 10-year experience of Brazilian and Italian centers with a large volume of cardiac surgeries.

[Table 1] summarizes the problems that we found in our extensive experience that can be related to the use of volatile agents vaporized in the CPB circuit. All these problems are associated to the vaporizer and to the analysis of the exhaled gases from the membrane oxygenator.
Table 1: Tricks and tips for the adapted vaporize system using volatile agents during cardiopulmonary bypass based on the 10 years' experience of two teaching hospitals (one in Italy and one in Brazil)


Click here to view


Until now, the technique of the use of volatile agents during CPB is an adaptation which includes the volatile agent vaporized into the circuit of the CPB machine mixed with the fresh gas flow (oxygen and compressed air) delivered from the blender. At first, the fresh gas flow from the blender enters into the calibrated vaporizer and is mixed with a desired concentration of the volatile agent. After that, the fresh gas flow, now mixed with a vaporized volatile agent, and enters into the circuit of the membrane oxygenator [Figure 1]. Many companies fail to mention that vaporizers can be included in their circuit and that the volatile agents can be used with standard membrane oxygenators. [8],[9]
Figure 1: Schematic representation of the use of volatile agents adapted to cardiopulmonary bypass machine

Click here to view


During the use of the volatile agents in CPB, it is very important to analyze all gases that come in and go out of the membrane oxygenators. The proper monitoring of inhaled and exhaled fraction of the gas allows not only the monitoring of anesthesia level, but also to detect possible leakage in the circuit. Nevertheless, most current oxygenators have redundant venting systems that eliminate the hazards of potential over pressurization inside the oxygenator which makes it difficult to measure precisely the volatile anesthetic levels in the exhaust port. In a prospective observational study, changes in sevoflurane plasma concentrations (SPCs) and bispectral index values during CPB were evaluated together with patient temperature, hemodilution, oxygenator fresh gas flow, and sevoflurane concentration in the exhaust gas from the oxygenator. [10] This study evidenced that SPCs were higher during hypothermia and with an increased fresh gas flow in oxygenator, while were lower with hemodilution. No correlation was found between SPCs and the concentration of sevoflurane in the oxygenator exhaust port gas, suggesting that leakages occurred from the main port during measurements. Moreover, most scavenging system devices used during this technique to evacuate the volatile gases from the operating room could be the cause of the reading line failure during monitoring.

Any volatile agent in the membrane oxygenator is supposed to pollute the operating theater. This is the major reason why proper scavenging systems are always necessary when this technique is used. The exposure limit for halogenated anesthetics is on average 2 parts per million (ppm), and it slightly changes according to the average over the period of anesthetic administration. It is important to mention that the olfactory thresholds typically is much higher than the 2 ppm. [11]

Recently, Nigro Neto et al.[8] described in a systematic review that the most serious accidents associated to the use of volatile agents during CPB are pollution of the room and cracks in the polycarbonate shell of the extracorporeal circuit components caused by spilled liquid volatile agent. Awareness is rare and seems to be associated to the type of membrane oxygenator used. Currently, there are two groups of hollow-fiber membrane oxygenators used in clinical practice [Table 2]. [12] The first type includes hollow-fiber membranes, primarily composed of microporous polypropylene, which is widely for standard CPB without having performances affected by the use of volatile agents. [9] The second type (diffusion plasma-resistant oxygenators) has the basic membrane compounded primarily of poly-(4-methyl-1-pentene). This type is increasingly used for extracorporeal life support or extracorporeal membrane oxygenation, and might increase the risk of intraoperative awareness during CPB by lowering the transfer of the volatile agent to the blood. [13],[14] To avoid this undesirable event, it is important to monitor the consciousness depth by monitoring systems such as bispectral index scale or by extrapolating plasma concentration from measured end-tidal anesthetic gas concentrations. [10] Moreover, proper scavenging system is utmost important along with strict patient monitoring during the delivery of these agents. Unlike bubble oxygenators (which rely on direct contact of blood and bubbles for gas exchange and are designed to separate undissolved gas from blood before the blood exits the oxygenator), membrane oxygenators are not designed to separate blood and bubbles of undissolved gas. Consequently, if large volumes of undissolved gas enter into the blood or are generated by back pressure in the membrane oxygenator, these will flow out of the oxygenator with blood. The potential for gas embolism exists if the outlet gas vent port of these oxygenators becomes either partially or totally occluded. Gas scavenging systems for these oxygenators must not cause the application of positive or negative pressures in the gas jackets as this may be dangerous. The American National Standards Institute (ANSI) standard (ANSI Z79.11) addressing scavenging systems for anesthetic gases apply to oxygenators as well as to anesthesia machines. This standard states that scavengers must not generate positive pressures exceeding 10 cm of water (7.4 mmHg) or negative pressures exceeding 0.5 cm of water (0.37 mmHg). [15]
Table 2: Difference in the hollow - fiber membrane oxygenators and their variability in transmembrane passage of volatile agents


Click here to view



   Conclusion Top


While waiting for industry upgrades, we recommend that volatile agents should be used during CPB only by skilled perfusionists and physicians with the aim to reduce postoperative morbidity and mortality.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
   References Top

1.
Nordén I. The influence of anaesthetics on systemic vascular resistance during cardiopulmonary bypass. Scand J Thorac Cardiovasc Surg 1974;8:81-7.  Back to cited text no. 1
    
2.
Landoni G, Biondi-Zoccai GG, Zangrillo A, Bignami E, D′Avolio S, Marchetti C, et al. Desflurane and sevoflurane in cardiac surgery: A meta-analysis of randomized clinical trials. J Cardiothorac Vasc Anesth 2007;21:502-11.  Back to cited text no. 2
    
3.
Bignami E, Biondi-Zoccai G, Landoni G, Fochi O, Testa V, Sheiban I, et al. Volatile anesthetics reduce mortality in cardiac surgery. J Cardiothorac Vasc Anesth 2009;23:594-9.  Back to cited text no. 3
    
4.
Jakobsen CJ, Berg H, Hindsholm KB, Faddy N, Sloth E. The influence of propofol versus sevoflurane anesthesia on outcome in 10,535 cardiac surgical procedures. J Cardiothorac Vasc Anesth 2007;21:664-71.  Back to cited text no. 4
    
5.
Landoni G, Rodseth RN, Santini F, Ponschab M, Ruggeri L, Székely A, et al. Randomized evidence for reduction of perioperative mortality. J Cardiothorac Vasc Anesth 2012;26:764-72.  Back to cited text no. 5
    
6.
Likhvantsev VV, Landoni G, Levikov D. Sevoflurane versus total intravenous anesthesia for isolated coronary artery bypass surgery with cardiopulmonary bypass: A randomized trial. J Cardiothorac Vasc Anesth 2016. Available from: http://dx.doi.org/10.1053/j.jvca.2016.02.030. [Last accessed on 2016 Feb 27].  Back to cited text no. 6
    
7.
De Hert SG, Van der Linden PJ, Cromheecke S, Meeus R, Nelis A, Van Reeth V, et al. Cardioprotective properties of sevoflurane in patients undergoing coronary surgery with cardiopulmonary bypass are related to the modalities of its administration. Anesthesiology 2004;101:299-310.  Back to cited text no. 7
    
8.
Nigro Neto C, Landoni G, Cassarà L, De Simone F, Zangrillo A, Tardelli MA. Use of volatile anesthetics during cardiopulmonary bypass: A systematic review of adverse events. J Cardiothorac Vasc Anesth 2014;28:84-9.  Back to cited text no. 8
    
9.
Nigro Neto C, Arnoni R, Rida BS, Landoni G, Tardelli MA. Randomized trial on the effect of sevoflurane on polypropylene membrane oxygenator performance. J Cardiothorac Vasc Anesth 2013;27:903-7.  Back to cited text no. 9
    
10.
Nitzschke R, Wilgusch J, Kersten JF, Trepte CJ, Haas SA, Reuter DA, et al. Changes in sevoflurane plasma concentration with delivery through the oxygenator during on-pump cardiac surgery. Br J Anaesth 2013;110:957-65.  Back to cited text no. 10
    
11.
National Institute of Occupational Safety and Health. NIOSH Pocket Guide to Chemical Hazards. Washington, DC: US Government Printing Office; 1994.  Back to cited text no. 11
    
12.
Gleen PG. Cardiopulmonary Bypass Principles and Practice. 3 rd ed. Philadelphia: Lippincott Williams and Wilkins; 2008. p. 47-9.  Back to cited text no. 12
    
13.
Philipp A, Wiesenack C, Behr R, Schmid FX, Birnbaum DE. High risk of intraoperative awareness during cardiopulmonary bypass with isoflurane administration via diffusion membrane oxygenators. Perfusion 2002;17:175-8.  Back to cited text no. 13
    
14.
Wiesenack C, Wiesner G, Keyl C, Gruber M, Philipp A, Ritzka M, et al. In vivo uptake and elimination of isoflurane by different membrane oxygenators during cardiopulmonary bypass. Anesthesiology 2002;97:133-8.  Back to cited text no. 14
    
15.
 Hazard. Scavenging gas from membrane oxygenators. Health Devices 1987;16:343-4. Available from: http://www.mdsr.ecri.org/summary/detail.aspx?doc_id=8093. [Last accessed on 2015 Sep 09].  Back to cited text no. 15
    

Top
Correspondence Address:
Giovanni Landoni
Department of Anesthesia and Intensive Care, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan
Italy
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0971-9784.179592

Rights and Permissions


    Figures

  [Figure 1]
 
 
    Tables

  [Table 1], [Table 2]



 

Top