To the Editor:—
The most important challenge an anesthesiologist faces on a medical mission in a developing country is to provide safe and effective care. Typically at these locations, one finds an old anesthesia machine. On our recent trip to Shimla, India, we found a Boyle anesthesia machine with a Goldblat halothane vaporizer. The local anesthesiologist was very comfortable with its use. Only one team member (H.J.K.) had ever seen and used such a machine, some 40 yr ago during his stay in the United Kingdom. The younger anesthesia team members had seen similar machines on other mission trips but declined to use them. Older anesthesiologists are a diminishing breed, whereas younger ones may fear the challenges of the past. There are no reports in the literature that have specifically addressed this problem. We decided to explore the possibilities.
In an ideal world, it would be prudent to send a scout team to the mission location beforehand to check on the availability of equipment and supplies, but our medical mission runs on a very restricted budget and cannot afford such an expense. Instead, we decided to develop a self-sufficient system with which all team members would be familiar and comfortable. Over time, our efforts have evolved into a sophisticated but low-technology approach to the problem of delivering safe anesthesia without a modern anesthesia machine.
At a first consideration, all medical facilities throughout the world where surgical procedures are performed seem to have large (size H) oxygen tanks available. This is the only item our system requires from the host country. Before our arrival, we arrange for a minimum of two H tanks for each operating room along with compatible gas tank regulators and low flow meters.
The equipment we bring is listed here: (1) a standard Compressed Gas Association oxygen regulator for the H tank along with a flow meter that delivers up to 10 l/min oxygen (usually, the host country's oxygen tanks do not have the standard threads, so we use the one provided by them); (2) standard plumber's sealing tape to obtain an airtight seal for the tank threads; (3) two pieces of standard suction tubing with universal connectors (Cardinal Health, McGaw Park, IL); (4) sevoflurane (Sevotec) and halothane (Fluotec) vaporizers together with 23-mm inlet and outlet adapters (General Anesthetic Services, Bridgeville, PA) to attach to the suction tubing (we routinely use sevoflurane, but we find it advantageous to have a halothane vaporizer because, in case of a supply problem, halothane is still readily available in developing countries, whereas sevoflurane is not); (5) portable disposable sealed carbon dioxide absorber (KAB 001; King Systems Corporation, Nobelsville, IN); (6) breathing circuits, Adult and Pediatric Ultra Flex, latex free (King Systems Corporation); and (7) an Ambu bag for use if there is any unforeseen problem.
The system can be assembled in less then 5 min. Segments of suction tubing connect the oxygen tank to the vaporizer and the vaporizer to the fresh gas inlet of the carbon dioxide absorber. The breathing circuit and the rebreathing bag are attached to the designated ports on the absorber. Anesthesia can proceed with either spontaneous or hand-controlled ventilation. The carbon dioxide absorber itself has a round bottom; hence, for ease of use, we put it into a small plywood box to keep it upright. A support stand is available from the supplier, but we find the wooden box more economical and easier to transport across the world. The absorber has an exhaust port to which we attached a standard long green corrugated plastic hose to carry the waste gases out of the operating room. Figure 1is a picture of the circuit.
It is important that the team members familiarize themselves with assembling the system and are comfortable with its use before leaving the home base. This precaution also assures that the correct size of adapters, tubing, and hose are available.
No system, however simple, is without some drawbacks. Oxygen tanks in different countries have different color codes and the gas content must be verified before use. Our system uses freestanding vaporizers that are physically very stable and are clearly labeled in red with a notice to be kept upright when charged. The team is well aware that an accidentally tilted vaporizer will deliver an increased concentration of the anesthetic agent. Great care must also be taken when refilling the vaporizer, which may not have an indexed filling port. There is no safety measure aside from full diligence in filling each vaporizer with the proper agent. At the end of surgery each day, all vaporizers are firmly secured to prevent accidental tipping. In use of the carbon dioxide absorber, it is well recognized that the inspiratory or expiratory valve mechanism may malfunction. Monitoring of end-tidal carbon dioxide levels during anesthesia alerts the anesthesiologist if there is a developing problem.
We have used Propaq (Welch Allyn, Beaverton, OR) transport monitors, which provide the standard heart rate, blood pressure, electrocardiogram, temperature, arterial blood oxygen saturation, and concentration of end-tidal carbon dioxide. We follow the guidelines set by the American Society of Anesthesiologists in monitoring our patients. We have no plans for changing the Propaq monitors in the foreseeable future, but someone starting from the beginning may wish to consider other monitors, such as the GE Health Care Datex-Ohmeda Cardiopac/5 (Datex-Ohmeda, Madison, WI), which also monitors inspired and expired oxygen and inhalational agents This would act as an added safety margin, because it confirms the veracity of the oxygen tank and the dialed concentration of the anesthetic agent.
On a recent mission to Shimla, India (World Missions Possible, Pearland, TX), we administered 92 anesthetics with three surgical teams over a period of 5 days. The surgeries included repair of cleft lip and palate (some children had a combined procedure) and plastic repair of scars and adhesions in severely burned children. We used three absorbers during the period. The work day was never longer than 10 h.
Most medical missions are on a limited budget. With this in mind, we found it possible to reuse the carbon dioxide absorber. There have been many reports in the literature showing that exposure of volatile anesthetics to desiccated carbon dioxide absorbents may result in exothermic reactions leading to production of toxic substances and a fire hazard in the breathing circuit. We made a ¾-inch hole with a trephine on one side of the absorber, removed the spent absorbent granules, and replaced them with fresh Medisorb granules (Datex-Ohmeda), which are safer then the old Baralyme granules. We placed a regular wine cork in the hole, which makes a very tight fit. The carbon dioxide absorber was back in service, and we experienced no problems. Alternately, a reusable carbon dioxide absorber (KAB 002; King Systems Corporation) is available. The one-way valve mechanism and the plastic pressure release valve (the pop-off valve), the two most important parts, are the same in both carbon dioxide absorbers, and the only difference is that in the reusable variety the manufacturer makes the hole on the side and provides a rubber stopper. Therefore, we decided to use the KAB 001 absorber and make the necessary adjustments ourselves while reducing our cost basis. Figure 2shows the two absorbers.
We found that this system has many advantages. Most importantly, it requires no sophisticated instrumentation and is low-technology, easily portable, lightweight, independent of electricity supply, comparatively inexpensive (less than $1,000 to outfit an operating room including the vaporizer, which once acquired is not a recurring expense), and easy to assemble and use.
The system we have described here has worked very well for us, and we have experienced no anesthesia-related complications. However, under normal conditions, anesthesia morbidity and mortality are indeed very low, and we realize that our 92 successes do not support a blanket statement. Nevertheless, we feel confident that the simplicity, ease of use, and portability of our system will prove our point. During the past two decades, multiple groups have participated in humanitarian medical missions throughout the word. It stands to reason that variations on the theme we describe must have been used by others, but there are no published reports to the effect. We very much hope that our report will be of help to a new group about to undertake a medical mission to an underdeveloped area. This system might also be useful in emergency conditions in the field or for makeshift operating rooms. We recommend this system for the administration of anesthesia in remote areas and developing countries or anywhere where a functioning anesthesia machine is not available.
*College of Physicians and Surgeons, Columbia University, New York, New York, and The Anesthesia Team of World Missions Possible, Pearland, Texas. firstname.lastname@example.org