Page 134 - JSOM Fall 2018
P. 134
if the anesthetic becomes too “light,” the patient will start to Disclaimer/Financial Conflicts
“breath up” or move, giving the anesthetist an indication that The authors received no financial support for this work. MWG
the patient requires more volatile. The technique could involve did not create it as part of his work requirements; it was writ
the following; ten on his own time. The authors have nothing to disclose.
1. Application of monitoring Author Contributions
2. Obtain IV access Both authors approved the final manuscript.
3. Preoxygenation with SIB connected to the drawover va
porizer using either bottled oxygen or oxygen concentrator References
4. IV induction using propofol or ketamine (an IV/inhalational 1. Pedersen J, Nyrop M. Anesthetic equipment for a developing
coinduction could also be performed by turning on the va country. Br J Anesth. 1991; 66: 264–270.
porizer to allow the patient to inhale volatile anesthetic— 2. Graves M, Cooper MG. Anesthesia at a casualty clearing station:
review of an Australian anesthetist’s role in the Great War. The
note this requires a wellfitting face mask and a good seal Proceedings of the 8th International Symposium on the History
or the patient will not draw any gas through the vaporizer) of Anesthesia. Australian Society of Anesthetists. 2016;189–199.
5. Insertion of LMA 3. Westhorpe RN. William Morton and the first successful demon
6. Connect patient nonrebreather valve to the LMA stration of anesthesia. Anesth Intensive Care. 1996;24(5):529.
7. Adjust vaporizer output control to deliver desired level of 4. Aldrete JA, Marron GM, Wright AJ. The first administration
anesthetic volatile concentration of anesthesia in military surgery: on occasion of the Mexican
American War. Anesthesiology. 1984;61:585–581.
8. Monitor for level of anesthetic using patients vital signs 5. Boumphrey S, Marshall N. Understanding vaporizers. BJACE-
eg pulse, BP, respiratory rate and depth, and adjust vapor ACCP. 2011;11(6):199–203.
izer output control accordingly 6. Eales M, Cooper R. Principles of anesthetic vaporizers. Anesth
9. Adjust inspired oxygen concentration in order to achieve Intensive Care Med. 2007;8(3):111–115.
adequate oxygen saturation 7. Hodges S. Paediatric drawover anesthesia. Updates Anesth. 2015;
10. If the patients respiratory system needs support this can 23–26.
be performed by assisting their respirations using the SIB 8. Borland CW, Herbert P, Pereira NH, et al. Evaluation of a new
range on air drawover vaporizers. The PAC series in laboratory
or through the use of a PEEP valve connected to the pa and field studies. Anesthesia. 1983;38:852–861.
tient valve. 9. Houghton IT. The Triservice anesthetic appartatus. Anesthesia.
1981;36:1094–1108.
3. Fasted child requiring elective or semielective surgery 10. Perndt HKS. The ULCO Anesthetic Suitcase. Anesth Intensive
It is possible to perform an inhalational induction using draw Care. 2002;30:800–803.
over equipment. The two things to keep in mind are; 11. Ohmeda Universal PAC Operation and Maintenance Manual.
http://www.frankshospitalworkshop.com/equipment/documents
/anesthesia/service_manuals/Ohmeda%20Universal%20
1. Without a complete seal of the face mask the carrier gas PAC%20%20Maintenance%20manual.pdf. Accessed 13 April,
will not be drawn through the vaporizer, resulting in no 2018.
volatile anesthetic being delivered to the patient 12. Stephens KF. Transportable apparatus for halothane anesthesia.
2. The maximal output from drawover vaporizers is less that Br J Anesth. 1965;37:67–72.
most plenum vaporizers (5% to 6% sevoflurane from two 13. Behne M, Wilke H, Harder S. Clinical pharmacokinetics of sevo
flurane. Clin Pharmacokinet. 1999;36(1):13–26.
OMVs in series compared with 8% from most plenum va 14. Hawkins JK, Ciresi SA, Phillips WJ. Performance of the universal
porizers). This will prolong induction. portable anesthesia complete vaporizer with mechanical ventila
tion in both drawover and pushover configurations. Mil Med.
If a perfect seal is not able to be obtained then volatile can 1998;163(3):159–163.
be delivered to the child by squeezing the selfinflating bag 15. Jowitt MD, Knight RJ. Anesthesia during the Falklands cam
to draw the carrier gas through the vaporizer. If the supply of paign, the land battles. Anesthesia. 1983;38:776–783.
oxygen is not an issue another option is to block the end of the 16. OMV 50 User Manual. Abingdon, Oxford, UK: Penlon Limited;
April 1997.
oxygen reservoir and increase the flow of oxygen to the vapor 17. Kocan M. The triservice anesthetic apparatustrial of isoflurane
izer to greater than the child’s minute respiration volume. This and enflurane as alternatives to halothane. Anesthesia. 1987;42
will drive the oxygen through the vaporizer and circuit to the (10):1101–1104.
face mask, effectively operating as a plenum vaporizer. 18. Liu EHC, Dhara SS. Sevoflurane output from the Oxford min
iature vaporizer in drawover mode. Anesth Intensive Care.
2000;532–536.
Conclusion 19. Knight RJ, Houghton MB. Field experience with the Triservice
anesthetic apparatus in Oman and Northern Ireland. Anesthesia.
With a renewed interest among SOF of operations in austere en 1981;36:1122–1127.
vironments and the support of indigenous forces, medical sup 20. Parkhouse J. Clinical performance of the OMV inhaler. Anesthe-
port elements need to be able to operate with a lighter footprint sia. 1966;21:498–503.
and be less reliant on the logistics chain and dedicated evacuation 21. Epstein HG, Macintosh R. An anesthetic inhaler with automatic
assets. In order to achieve this all medical specialties will need thermocompensation. Anesthesia. 1956;2(1):83–88.
to look at how they provide medical care and in particular pro 22. Schafer HG, Farman JV. Anesthetic vapour concentrations in the
EMO system. Anesthesia. 1984;39:171–180.
longed field care with lighter equipment and less consumables. 23. English WA, Tully R, Muller GD, et al. The Diamedica Draw
Drawover anesthesia was a vital instrument for anesthetic pro over Vaporizer: a comparison of a new vaporizer with the Oxford
viders located in FSTs during the mobile phases of the Afghani Miniature Vaporizer. Anesthesia. 2009;64(1):84–92.
stan campaign. Its light weight, portability, inherent robustness, 24. Klineberg PL, Bagshaw RJ. Hypoxaemia and general anesthesia:
and the ability to use multiple anesthetic agents including ones an analysis of distribution of ventilation and perfusion. Int Anes-
thesiol Clin. 1981;19(3):123–168.
that may be able to be sourced locally makes it a worthy instru 25. Depledge MH. Peak inspiratory flow: measurement using a mod
ment to be included in the modern SOF medical armamentarium. ified mini write peak flow meter. Thorax. 1985;40:205–206.
132 | JSOM Volume 18, Edition 3 / Fall 2018

