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4 Emergency and Continuing Care Dreams are like stars: you choose them as your guides and following them, you reach your Destiny. Inscription on the wall of the science laboratory Destiny revealed on the opening day for Destiny on the International Space Station, February 11, 2001, accompanied by signatures of those who assembled the module One or more acute severe emergency medical events such as a traumatic injury, toxic exposure, or acute cardiopulmonary decompensation will prob- ably occur on a long-duration space mission. Some will resolve or at least improve quickly with treatment, others may require continuing care, and others may require resuscitative measures. The decision to initiate resuscita- tion or determine end points is complex and must be based upon the best judgment of the medical command on the International Space Station (ISS) and future spacecraft. Factors to be considered include whether there are single or multiple incidents, the resources available to treat the patient, and the operational impact upon the crew of the potential loss or extended dis- ability of the patient. Case reports from the Australian National Antarctic Research Expeditions experience (Pardoe, 1965; Priddy, 1985; Taylor and Gormly, 1997) suggest that ingenuity and determination can be used during the treatment of unusual situations, so restrictive guidelines for the with- 117
118 SAFE PASSAGE drawal of care or for the provision of only supportive care should be avoided. Other factors to consider include resource utilization in the event of mul- tiple illnesses or casualties, identification of specific roles for caregivers, an- ticipated end points of treatment, and communication with the ground crew to assist in prioritization of care. Health Care Opportunity 15. Developing a resource-based medical triage system that contains guidelines for the management of individual and multiple casualties during space travel. ANESTHESIA AND PAIN MANAGEMENT During long-duration space missions, anesthesia and pain management may be required for unanticipated accidents (e.g., fractures of bones, lacera- tions, or blunt trauma), medical conditions (e.g., appendicitis or a perfo- rated viscus), and possibly, cardiopulmonary resuscitation. This aspect of health care in microgravity presents major challenges. Inhaled volatile and gaseous anesthetics must be avoided because of leakage of subanesthetic doses in a controlled environment, limited knowledge of gas diffusion in zero gravity, and the necessity for endotracheal intubation. The spacecraft poses many challenges that need to be resolved before anesthesia and pain management can be delivered safely. First, the limited amount of physical space available not only will dictate the use of smaller equipment but also may preclude the use of some instrumentation that is standard during anesthesia delivery on Earth. The second challenge will be the selection of an astronaut(s) who has the technical skills necessary to ad- minister the various components of anesthesia. Airway Management in Space It will be essential to have on board spacecraft astronauts who have requisite training in airway management, along with strategies for retaining these skills. However, success in applying some of the most effective meth- ods of airway management requires frequent and regular practice, in the opinion of members of the committee who as part of their professional ac- tivities have expertise in airway management, and it is not likely that an individual with such characteristics will be on board the spacecraft. There- fore, techniques that are based on the likelihood of success should be cho- sen, and these should be consistent with the skills of the individuals on board. The types of airway equipment and techniques required will partly
EMERGENCY AND CONTINUING CARE 119 be based on the type of surgery and trauma anticipated. Decisions regarding long-term airway care need to be made before such equipment and tech- niques are selected. Lastly, because airway management is usually required for successful cardiopulmonary resuscitation, the need for airway manage- ment during anesthesia should be coordinated with the need for cardiopul- monary resuscitation. To minimize morbidity and mortality, two approaches should be fol- lowed. The first is to use an anesthetic technique that does not require en- dotracheal intubation. The second is to avoid the use of neuromuscular sys- tem-blocking drugs. Anesthesia with the latter can facilitate an overall view of the trachea during endotracheal intubation, but if the trachea cannot be intubated, the patient is left totally dependent on the clinician for adequate ventilation. Controlling ventilation in a paralyzed individual is often difficult (Caplan et al., 1993; Parmet et al., 1998). Little is known about airway management in an atmosphere of microgravity. Studies have been performed in simulated microgravity in a submerged full-scale model of a space module with neutrally buoyant equip- ment and personnel. The ability to control the airway in a free-floating sub- merged manikin was attempted with four different devices. Endotracheal intubation was unsuccessful in 10 to 15 percent of the situations, whereas other airway devices were more successfully implemented (Keller et al., 2000). Although this was useful initial information, the study with a manikin in no way simulates clinical conditions and the mental pressure associated with the need to control an airway in a life-and-death emergency. These studies emphasize the potential for serious morbidity when inten- sive airway management is needed for either anesthesia or resuscitation. These clinical problems could contribute to the need for long-term care on board the spacecraft. Because the possibility of failure of endotracheal intubation is real, less demanding techniques should be considered, even if they do not protect the airway from vomiting and aspiration as well as endotracheal intubation does. Insertion of a laryngeal mask is technically much easier, and it provides an excellent airway. In the simulated atmosphere of microgravity, use of a la- ryngeal mask has been more successful (Keller et al., 2000). Anesthetics Although inhaled anesthetics, both volatile and gaseous, are extremely useful and helpful, they should not be considered for use in space travel at
120 SAFE PASSAGE this time, as stated above. Until the problems associated with gas-liquid interfaces in microgravity can be solved, intravenously administered anes- thetics should probably be used. Although such anesthetics can be given by bolus administration, constant infusion achieves more sustained levels of anesthetic in the blood and brain, but constant infusion would require ap- propriate infusion pumps. These are small, however, and should be readily accommodated on a spacecraft. Nevertheless, basic technical procedures, such as procedures for the insertion of a reliable intravenous catheter, need to be reviewed, modified, or redesigned where necessary and need to be practiced. In general, the drugs used should be associated with a rapid recovery and, preferably, should have an antagonist. These drugs should not cause significant cardiorespiratory depression. Unfortunately, no ideal drug with all of these characteristics exists at present. Regional Anesthesia The major advantage of regional anesthesia is that it anesthetizes only that part of the body that needs to be anesthetized and does not have the disadvantages associated with anesthetizing the entire body. It also has the advantages of maintaining the patient awake and facilitating a rapid recov- ery and postoperative analgesia. Of prime importance on a spacecraft is what should be done if the re- gional anesthetic turns out to be inadequate for surgery. The nerve block procedure can be repeated (with the added potential complication of nerve toxicity), or a general anesthesia can be induced. Direct nerve injury and hematoma must be considered from use of the nerve-blocking procedure, although those are extremely rare complications on Earth. The team must be prepared to deal with central nervous system excitation and possible con- vulsions with short- or intermediate-action local anesthetics (e.g., lidocaine) and cardiotoxicity with the longer-acting drugs (e.g., bupivicaine). Despite numerous potential problems, crew medical officers could be trained in the delivery of regional anesthesia in an effective manner. After conducting proper research on the effects of microgravity on the diffusion and nerve toxicities of local anesthetics, these will probably be the agents of choice. Health Care Opportunity 16. Developing an anesthetic approach associ- ated with rapid and comfortable recovery using anesthetic drugs with short durations of action or for which there are antagonists.
EMERGENCY AND CONTINUING CARE 121 SURGERY AND TRAUMA In the most basic sense, surgery is controlled trauma. Successful man- agement of both accidental trauma and the controlled trauma of surgery requires several elements working in concert. From the standpoint of the health care provider, control of pain (anesthesia), control of bleeding (ho- meostasis), and technical expertise are just the beginning. Because anesthe- sia and pain control are considered separately, this brief summary will con- centrate on the remainder of the significant issues surrounding surgery and trauma. Physiological Responses to Injury The physiological alterations that accompany long-duration space mis- sions may well affect homeostasis, wound healing, and resistance to infec- tion, all of which are crucial for recovery from trauma or surgery. Any wound sets into motion a complex series of events under neurohumoral system con- trol termed the âresponse to injury.â The time course has been fairly well delineated in the normal Earth environment, and the routines of postopera- tive and postinjury care are based upon the assumptions implicit in this model of events (Greenfield, 1996). The initial studies upon which this model is based were performed in the 1930s and have been refined by innu- merable clinical and laboratory observations over the intervening decades to derive assumptions about fluid and electrolyte balance, changes in hormone levels, metabolic changes, cytokine activation, and immunological alterations after injury. Essentially nothing is known about how this neurohumoral re- sponse to injury is modified by microgravity. Although it may not be realistic to replicate these myriad physiological studies during the postoperative period, carefully designed experiments with simple outcomes measures (supplemented by highly selected physiological, histological, or metabolic studies) performed in a microgravity environment such as the ISS after surgery in animals might yield significant information of value. Take one example: the response to hemorrhage and fluid resuscitation. Cardiovascular adaptations and changes associated with microgravity will probably alter the response to hemorrhage and fluid resuscitation. Without gravitational pooling, will fluid volumes required for resuscitation from a standard hemorrhage be the same, greater than, or less than those required on Earth? What fluids should be used, and at what volume? What (if any) blood substitutes should be used? Would the use of a counterpressure de-
122 SAFE PASSAGE vice (such as military antishock trousers) help? Or would the use of such a device prove detrimental or nonproductive in an environment lacking the capability to obtain definitive control of hemorrhage? To stop bleeding and achieve homeostasis, the surgeon applies mechani- cal methods (ligatures, cautery, hemostatic clips) that are likely to be quite effective in microgravity (Campbell and Billica, 1992; Colvard et al., 1992; Campbell et al., 1993, 1996; Campbell, 1999). In addition, new methods are continually being devised; for example, an ultrasound-activated method of sealing blood vessels has been demonstrated to have significant advantages in minimal-access surgery, supplanting the traditional electrocautery for many applications (Gossot et al., 1999). Continued developments can be anticipated, as this is a major area of focus in civilian and military medical practice. Similarly, new methods of wound closure are continually being devised as alternatives to sutures or staples. For example, both biological and artifi- cial adhesives are under continual improvement (Quinn et al., 1998; UHSC, 1999). These may be supplemented, when necessary, by a surgical zipper applied in such a fashion as to pull the edges of the wound together. This provides mechanical support for a âsuturelessâ closure (Mulvihill, 1999) that is quick and painless and that may be more resistant to infection than the closures achieved by more conventional methods. Surgical homeostasis requires not only mechanical control of bleeding but also complex interrelated mechanisms of blood coagulation and fibri- nolysis. As an example of unexpected issues that may emerge when actual surgery is performed or major injuries are treated, Campbell and colleagues (1993) noted that venous bleeding appeared to increase during surgery per- formed during parabolic flight. They hypothesized that gravitational forces on tissues normally contribute to the collapse of veins and help staunch the flow of blood when surgery is performed on Earth. In microgravity, how- ever, such forces on tissue are nonexistent and external compression must be supplied. Practical lessons such as those about venous bleeding are best learned by carefully designed studies with animals. Although immediate control of bleeding in microgravity has been dem- onstrated to be achievable by conventional means, it is not known whether long-duration space missions may result in subtle alterations in blood co- agulation activity (e.g., platelet dysfunction or hyperfibrinolysis) that might require additional hemostatic maneuvers or the use of topical hemostatic agents. Anecdotal experience from Mir suggests that minor cuts take longer to heal, but it is dangerous to generalize this to an assumption that wound
EMERGENCY AND CONTINUING CARE 123 healing may be prolonged. Incomplete healing has been observed for muscles and bones injured in rats before spaceflight in the Cosmos biosatel- lite series, and brief daily exposure to near-infrared light appears to promote epithelial wound healing (Baibekov et al., 1995; Korolev and Zagorskaia, 1996). Of greater concern than soft-tissue healing is the probable impact of bone demineralization upon healing of fractures. Fractures may be casted, internally fixed, or externally fixed. Although each of these methods has its advantages, neither casting nor external fixation would seem to allow access to a pressure suit, should this be required. Better information about how bone heals in microgravity would be extremely helpful. Innovative methods such as percutaneous injection of bone adhesives or growth factors-growth promoters might be available (AAOS, 1996). Adequate nutritional support has revolutionized the management of sur- gical illnesses ranging from burns through trauma and infection. The neuro- humoral response described above increases metabolic demands by 15 to 25 percent for a fracture of a major long bone (e.g., the femur) and 50 percent for multiple trauma (Greenfield, 1996). Ileus commonly accompanies burns, trauma, and surgical illness and may be exacerbated by the hypomotility associated with microgravity (Harris et al., 1997). This may make it impos- sible to maintain caloric intake; hence, short-term nutritional support may be needed during recovery from an acute illness or trauma. Consideration should be given to ways in which this might be accomplished within the realistic constraints of the mission. A simple way to monitor the adequacy of nutritional support, for example, urinary nitrogen excretion as a measure of nitrogen balance, would be helpful if it could be validated in microgravity. Surgical Skills and Training A word about remote or telepresence surgery is in order. By this method of surgery, a surgeon in a remote location controls robotic instruments that perform the actual surgery. It has been demonstrated to be feasible and is being explored for some applications in remote locations on Earth. How- ever, even the slight transmission delay involved in transcontinental distances has proved problematic (DiGioia et al., 1998; Satava and Jones, 1998). Thus, in a mission beyond Earth orbit, transmission blackouts and delays will cer- tainly limit its usefulness. Therefore, the roundtrip time lag (40 minutes or so once the mission is near Mars) negates the use of telesurgery and even
124 SAFE PASSAGE real-time telementoring at this time, even though these methods have proved feasible on Earth. Robotic surgery has captured public interest and enthusiasm. At present, surgical robots operate under the direct control of a human surgeon, who is usually in the same room. Currently, they are dependent on gravity. The robotic assistant is used to scale down movement and eliminate unwanted motions, allowing smaller, more precise sutures to be placed (Satava and Jones, 1998; Borst, 2000). Although rapid developments in this field are anticipated (Campbell et al., 1996; Satava and Jones, 1998; Campbell, 1999, Maniscalco-Theberge and Elliott, 1999), the application of robotic assistance to long-duration space missions is uncertain. Combinations of ultrasound- based diagnosis with computer-assisted positioning of therapeutic instru- mentation may, in the future, make robotics a valuable technology for space medicine. A combination of computer-guided, robotic, and human hands- on expertiseâincluding crew medical officer training and proficiency in evolving, minimally invasive surgical techniques such as laparoscopyâwill be necessary, backed by data in an onboard computer might provide the best solution for complex low-probability problems. Surgical Equipment What surgical equipment should be taken on a space mission beyond Earth orbit several decades from now? Therapeutic options will be limited by the available drugs, equipment, and supplies. Thus, the choice of surgical equipment and supplies and the choice of procedures that will be performed seem to be inextricably linked. Yet, with computer-assisted design and com- puter-assisted manipulation (CAD-CAM) technology, it is possible to fabri- cate small parts to order from specifications contained in an onboard data- base or transmitted from Earth (Heissler et al., 1998; Okumura et al., 1999). Thus, it is conceivable that a seldom used surgical instrument (or an implant needed to stabilize a fracture) could be fabricated as needed and then re- cycled when it was no longer needed. Such technology is already available, and future application to surgical parts and instruments is likely a cost-effec- tive way to achieve a just-in-time solution to a major problem on a space- craft: the lack of hospital supplies. CAD-CAM equipment may well be in- cluded in a Mars mission for other (nonmedical) purposes; the task would thus be ensuring that materials and specifications were consistent with medi- cal applications as well. The availability of this kind of technology dramati-
EMERGENCY AND CONTINUING CARE 125 cally expands therapeutic possibilities and emphasizes the need for skills acquisition by space crews. By using todayâs standard of care as a guide, basic diagnostic equipment would include a high-resolution imaging system, an ultrasound unit, or con- ceivably, a compact magnetic resonance imager. This allows the detection of abscesses, bleeding, and pneumothorax and the performance of image- guided interventions (see Management of Abscesses and Soft-Tissue Infec- tions below). In current trauma practice, a focused ultrasound evaluation has proved to be rapid and reliable in ruling in or out certain kinds of inju- ries (Bode et al., 1999; McCarter et al., 2000). This is another area in which multiple civilian applications are driving a rapid pace of technological inno- vation that could be adapted for use in space medicine if it is validated in microgravity. Whatever system is chosen may well need to be tested on healthy human subjects in microgravity, as anatomic landmarks shift with- out the constraints of gravity. Technical Aspects of Surgery In a microgravity environment, special mechanical problems such as anchoring both the patient and the operating team, maintaining a sterile field, and controlling blood and body fluids can be anticipated (Kirkpatrick et al., 1997). The mechanics of both open and laparoscopic techniques have been explored during parabolic flight, and the feasibility of these techniques with suitable modifications has been demonstrated. During open surgery, control of body fluids with sponges and suction appears to be adequate if the patient has normal hemostatic capabilities (Campbell and Billica, 1992; Colvard et al., 1992; Campbell et al., 1993, 1996; Campbell, 1999). Special adjuncts such as transparent plastic shields to provide containment of arte- rial bleeding can easily be designed and tested either in parabolic flight or on the ISS. Laparoscopic surgery is an attractive option that has been demonstrated to be feasible in a porcine model during parabolic flight (Campbell et al., 1996). Other forms of minimal-access surgery may similarly prove to be both feasible and advantageous. Because the incisions used are small, recovery is usually rapid and limitations of physical activities are minimized. Better con- tainment of body fluids is an additional advantage when working in microgravity. Minimal-access surgical simulators are already available, and it may be particularly easy for those who already have excellent eye-hand coor- dination skills to learn the techniques.
126 SAFE PASSAGE The preceding information and examples illustrate the accelerating in- tegration of engineering and biology. The committee encourages the Na- tional Aeronautics and Space Administration (NASA) to track these and other emerging opportunities closely to apply them to space medicine as the technology develops to meet the need. Prevention of Infection Accidental wounds (such as lacerations and open fractures) are consid- ered contaminated and require therapeutic administration of antibiotics as well as judicious surgical management to prevent devastating infectious com- plications in the best of circumstances (Singer et al., 1997; Luchette et al., 2000). Infection is possible even after clean, elective surgery. This may be more likely when surgery is performed during a mission. Breaks in sterile technique may be more likely in microgravity, the microflora is altered among individuals in close confinement (i.e., individuals share microorganisms), and there may be alterations in immune function in astronauts. Prophylactic antibiotics have been shown to decrease the probability of wound infection and are commonly used in current surgical practice (McCuaig, 1992; Bold et al., 1998; Weigelt and Faro, 1998). Selection of antibiotics for prophylactic and therapeutic purposes should be based upon knowledge of the microflo- ras that colonize the skin and gastrointestinal tract, coupled with pharmaco- logical considerations (e.g., frequency and ease of administration and poten- tial toxicity). Management of Common Surgical Emergencies Although one can anticipate the most common surgical emergencies from demographic and analog-environment data, unanticipated events can and do occur. A subarachnoid hemorrhage was managed by physicians in Antarctica, despite inadequate facilities, through ingenuity and innovation (Pardoe, 1965). Whether such a heroic effort could be undertaken or should be undertaken in the context of a space mission is doubtful, but it serves to show the human drive to preserve life, even against all odds. It also demon- strated how improvisation led to a successful outcome. Although it is not possible to plan for all emergencies, it may be possible to facilitate improvi- sation by providing the basic materials. Fairly good data on the incidence of likely surgical emergencies are avail- able from demographic and analog environments (Lugg, 2000). Anticipated
EMERGENCY AND CONTINUING CARE 127 emergencies include acute appendicitis, abscesses, incarcerated hernias, and trauma. Acute appendicitis is of particular interest because it provides a clear example of a common surgical emergency that has been approached in various ways over the past decades in an effort to avoid the necessity of an untrained person performing an appendectomy in a remote environment. In 1979, studies in Antarctica documented an increased incidence of acute ap- pendicitis (Lugg, 1979) and led to the recommendation that the team physi- cian undergo prophylactic appendectomy. The spectrum of measures avail- able to avoid performance of an appendectomy in a remote environment ranges from prophylactic appendectomy before the mission to treatment of appendicitis with antibiotics with later (interval) appendectomy and to the use of antibiotics supplemented by percutaneous drainage of any abscess that might form. Management of Abscesses and Soft-Tissue Infections Abscesses and other soft-tissue infections are treated with antibiotics and by drainage or debridement, as needed. Image-guided (probably ultra- sound-guided) percutaneous drainage (Nakamoto and Haaga, 1995; Mont- gomery and Wilson, 1996; Shuler et al., 1996; Miller et al., 1997; Scott et al., 1997; Wroblicka and Kuligowska, 1998; DâAgostino, 1999) would seem to be an ideal method for the management of deep-seated abscesses (as well as some less common conditions such as acute cholecystitis refractory to anti- biotics). This technology is well proven as a safe and effective alternative to surgical drainage under the proper conditions and with concurrent antibi- otic therapy. REHABILITATION FOR ASTRONAUTS ON LONG- DURATION MISSIONS Few controlled studies have assessed the contributions that rehabilita- tion interventions make to the prevention of the loss of lean mass in pro- longed microgravity. The information learned from existing studies with both humans and animals is inadequate (NASA, 1997). This is true for existing studies of both of preflight ground-based training and in-flight ex- ercise. Similarly, little is known about whether preflight training or onboard exercise has a mitigating effect on the loss of bone mineral density or muscle mass. Exercise strategies and techniques have not been selected on the basis
128 SAFE PASSAGE of the results of evidenced-based trials, and treatment protocols have not been developed (NASA, 2000a). Techniques for improving muscle strength and aerobic capacity pre- flight have not been tested for efficacy or efficiency. In-flight exercise has been aerobic; and although it helps to maintain a sense of focus and achieve a psychologically stable state (Linenger, 2000), in at least Dr. Jerry Linengerâs case on Mir, the level of bone mineral density loss reached 13 percent after 5 months. Modification of existing practice, such as concomitant use of elec- trical stimulation or electromagnetic field stimulation, might provide an im- petus for bone growth (Liu, 1996). Galvanic stimulation has had a benefit in maintaining muscle mass in patients postoperatively when they are kept in a non-weight-bearing state (Oldham et al., 1995). The use of devices that cre- ate bending moments of force might be useful, but no data are available to support this hypothesis. Significant literature exists to support the use of other rehabilitative techniques to improve performance and provide a sense of well-being. These include biofeedback, gated breathing, transcendental meditation, and yoga. Movement therapies and deep soft-tissue massage have not been tried as part of routine training or in-flight management techniques designed to re- duce stress. Data about the effectiveness of these techniques suggest that they may help with anticipatory nausea and anxiety in medical settings and may assist with regulation of the autonomic nervous system (Shapiro and Schwartz, 1972; Schwartz, 1979; Fehr, 1996; Murphy, 1996; Agathon, 1998). The needs for rehabilitation on board during protracted missions, be they ISS missions or missions beyond Earth orbit, must address the issues of maintenance of lean mass and bone mass and restoration of bone mineral density after trauma or disuse because of illness and maintenance of muscu- loskeletal system performance (both fine and gross motor). Strengthening exercise by an isotonic approach with resistance has been the technique used on Earth to preserve and restore lean muscle mass. This has not been methodically used on board spacecraft, and equipment that facilitates resistive exercise activity has not been routinely sent into space. Most efforts have been spent in supporting aerobic training, using a tread- mill for exercise, but few data on the effect of this training on aerobic capac- ity or cardiac function have been published. Restoration of musculoskeletal system function following trauma has not been investigated and should be studied systematically in the case of injury (i.e., fracture or soft-tissue dam- age) on board a spacecraft. The role of leisure and recreational activity to combat boredom and
EMERGENCY AND CONTINUING CARE 129 maintain fine motor and gross motor skills has not been fully evaluated. Yoga, relaxation training, and leisure activity may promote psychological well-being and improvements in coping strategies, vigilance, and perfor- mance. Nonpharmacological treatments for pain may also play a role in promoting well-being and reducing anxiety. Treatments shown to be effec- tive include modalities of heat and cold, transcutaneous stimulators, acu- puncture, and acupressure. The techniques of administration are easily taught, and the equipment needed is readily available and inexpensive. No information is available about its usefulness in space. Restoration of function upon the return to Earthâs gravity has been nearly complete in most instances, although full restoration of the bone min- eral density that has been lost seems refractory to current treatments, which have mainly been exercise based. Nonpharmacological techniques for the stimulation of bone repairâfor example, the use of electrical stimulators or electromagnetic field generatorsâhave not been used. NASA recently convened a working group on astronaut physical train- ing and rehabilitation research and included in it a representative of the Russian Space Agencyâs rehabilitation program. During a 2-day workshop at the Johnson Space Center (NASA, 2000a), NASA asked the group to de- velop recommendations for preflight physical training, postflight rehabilita- tion, and rehabilitation after injury. NASA also asked the group to review its plans for a new bioastronautics facility, which would include a rehabilitation unit with increased staffing and new equipment. In its key finding, the working group cited ample evidence of decondi- tioned astronauts returning from lengthy stays on Mir with physical defects. It said that this is an occupational health issue that must be addressed by an active rehabilitation program. The working group cautioned, however, that the techniques used for physical conditioning and rehabilitation on Earth have yet to be shown to be successful in the care of astronauts in space and that clinical research is needed. The working group recommended that NASA investigate the use of new drugs for the treatment of osteoporosis, assess the effects of intense in-flight exercise, evaluate the Russian Space Agencyâs program of preflight and in- flight vestibular training, and develop strength standards for hand and fore- arm muscles (important for astronauts participating in extravehicular activi- ties). Other recommendations focused on ways to increase motivation, compliance, and team cohesiveness. The committee encourages NASA to continue its efforts in this area of astronaut health. Research on the efficacies of rehabilitation interventions
130 SAFE PASSAGE and their mechanisms of action in this population should be undertaken by using ISS and Earth environments that are designed to simulate the effects of microgravity. Special effort could be made to determine what equipment needs to be installed on the ground or in space to facilitate appropriate rehabilitative interventions for preservation of lean mass and bone mineral density, good psychosocial interactions, and other conditions requiring re- habilitative treatment during a long-duration space mission. CATASTROPHIC ILLNESS, DEATH, AND END-OF-LIFE CONSIDERATIONS Guidelines for withdrawal of care and the provision of assistance to survivors should be developed for long-duration space missions. Resuscita- tive end point guidelines have been developed on Earth after years of expe- rience and ethical discussion and have been limited to a few situations. There are no clear criteria that can predict the futility of cardiopulmonary resusci- tation accurately. Responsibility for termination of medical resuscitative ef- forts rests with the responsible clinician (AHA, 2000). Health Care Opportunity 17. Creating guidelines for withdrawal of care in space and for dealing with the death of a crewmember from physi- ological and behavioral points of view. Consequently, an essential part of preparing for prolonged space travel is an open discussion of the principles and practices of resuscitative and supportive care. Practice principles to be developed include establishment of the chain of command during an emergency medical situation or during mission-altering or mission-ending situations in which restorative care is im- possible, methods for stabilization of the astronaut-patient for the return to Earth, and methods for pain control and psychological support for life-end- ing conditions in the space environment. A clearly developed process for deciding what to do and how to proceed in the unfortunate instance of the death of an astronaut must also be fully undertaken and accepted by the astronaut crew, their families, and ground personnel before embarking upon a long-duration mission beyond Earthâs orbit. There is a great deal of gen- eral maritime and Naval experience with this problem and a long history of practice in war and peace that could provide useful guidance on what to do and not to do in developing space medicine policy in this area.
EMERGENCY AND CONTINUING CARE 131 PERSONNEL AND OTHER HEALTH CARE RESOURCES The committee believes that, according to current standards of practice, the medical community and the general public would expect a physician to be part of a crew during a period of extended space travel and strongly supports that concept. There are, however, hostile remote environments on Earth where medical care is routinely provided by an individual other than a physician (British Antarctic stations and U.S. submarines). Whether or not a physician should be an integral part of a long-duration space mission will be determined by a number of factors including crew number, the length of the mission, the duties of crewmembers, and the standard of health care expected during the mission. If a physician is part of the crew, however, a number of needs must be met. Cross-training of several or possibly all crew members in selected skills is necessary in the event that there are multiple illnesses or injuries that need simultaneous care or in the event that the physician is disabled or becomes ill in flight. At least one nonphysician on the space crew should be trained to the emergency medical technician-paramedic level by todayâs standards. The physician should have broad training and possess the general skill sets re- quired for the evaluation and treatment of major illnesses and injuries in- volving organ systems and the identification and treatment of environmental illness and injury. The physician should also be trained in the technical pro- cedures that will most likely be needed in the space environment, where evacuation to Earth for treatment is not possible. Methods should be devel- oped for skill maintenance, retraining in those psychomotor skills that are most likely to be affected by microgravity, and the use of instructional and communication technologies such as telemedicine and virtual reality. The special skills actually required for performance of surgery can be acquired, augmented, or practiced by using simulators and a hybrid technology that has been termed âcybersurgeryâ (Satava, 1997; DiGioia et al., 1998; Satava and Jones, 1998). Training and retraining in clinical decision-making skills, clinical problem solving, and decision making for multiple casualties or ill- nesses are also necessary. Health Care Opportunity 18. Developing a mechanism for skill mainte- nance and retraining in psychomotor skills during long-duration space missions. The most important resource for care is the physician and the other members of the health care team, who must rapidly synthesize clinical and
132 SAFE PASSAGE cognitive information to provide a diagnostic and treatment plan for the patient, as communication with medical specialists on Earth may or may not be possible or effective when needed. It is estimated that communication with Earth or satellite stations will be available only 50 percent of the time and that there will be up to a 40-minute round-trip communication delay, depending on the spacecraftâs proximity to Mars. These estimates reinforce the necessity not only for independent action but also for a full spectrum of resources on the spacecraft. Diagnostic and therapeutic resources should be available, including computerized teaching resources and computerized references. A comprehensive drug database would be helpful. The crew should also be able to repair, maintain, and if necessary, fabricate equipment to perform diagnostic and therapeutic tasks adequately. Medical supplies that can be reused, reconstituted, or somehow replenished in the spacecraft environment should also be part of this future. Development of a Space Medicine Catalog and Database During the space mission, routine surveillance of health measures should be conducted and all episodes of illness and injury should be recorded. Sys- tematic record keeping with a computerized database will be necessary so that data can be accessed periodically and also used for identification of diagnostic and therapeutic errors and continued health care planning. Sex and cultural differences should be identified as part of surveillance of health measures. A centralized catalogue for all peer-reviewed manuscripts, ab- stracts, reports, handouts, mission log summaries, and monographs related to space biomedical research, health care, and relevant studies in analog environments (Lugg and Shepanek, 1999) should be developed. Access should be maintained through a centralized database with contemporary medical information on personnel and equipment. All material should con- tain the date and the responsible author(s). This is important, because re- sources could well be available but not used because they are not accessible and because promising information regarding countermeasures or impor- tant biomedical associations could be missed because the material is un- known or unavailable. The databases on board the spacecraft could be con- tinuously updated as newer scientific information becomes available. The Australian National Antarctic Research Expeditions Health Regis- ter is one model for such a database (Sullivan et al., 1991; Sullivan and Gormley, 1999). The database system should include descriptions of the
EMERGENCY AND CONTINUING CARE 133 illnesses and injuries that occur in microgravity, track normal health status measures, assess the types of illnesses and injuries and risks of exposure, determine the effectiveness of exposure modifications, track procedures per- formed by individuals and by the group, track the therapeutic agents that have been administered, and have a system for the coding of each episode of illness and injury according to the International Classification of Diseases and emergency medical code groupings. These codes should be expanded to include codes for dental problems. New emergency medical codes will likely need to be developed for the microgravity environment. Standardized rates for reporting of incidents, such as the numbers of incidents per person- day, should be adopted so that rates from different missions can be com- pared. Health Care Opportunity 19. Recording routine surveillance of health status measures, incidents of illnesses and injuries, and their treatments in a database with standardized rates of occurrence so that data between studies and missions can be compared. Health Care Opportunity 20. Developing and maintaining a centralized catalogue of all written materials related to space and analog-environ- ment biomedical research and experience according to current medical informatics standards. The health care opportunities that are described in this chapter and that may be explored to increase the future effectiveness of managing risks to the health of astronauts during space travel are listed in Box 4-1. These should be evaluated in addition to the health care opportunities provided in Chap- ter 3. Further opportunities will accrue as the field of space medicine con- tinues to develop. As health care opportunities during space missions are explored, they will contribute substantially to the evidence base for the de- velopment of the appropriate means of management of medical events con- sidered to be within the scope of care for long-duration space travel. CONCLUSION AND RECOMMENDATION Conclusion Exploratory missions with humans involve a high degree of human- machine interaction. The human factor will become more important as the durations of missions into deep space with humans increase and as
134 SAFE PASSAGE BOX 4-1 Health Care Opportunities in Space Medicine (continued from Chapter 3) 15. Developing a resource-based medical triage system that contains guidelines for the management of individual and multiple casualties during space travel. 16. Developing an anesthetic approach associated with rapid and comfortable recovery using anesthetic drugs with short durations of action or for which there are antagonists. 17. Creating guidelines for withdrawal of care in space and for dealing with the death of a crewmember from physiological and behavioral health points of view. 18. Developing a mechanism for skill maintenance and retraining in psychomotor skills during long-duration space missions. 19. Recording routine surveillance of health status measures, incidents of illnesses and injuries, and their treatments in a database with standardized rates of occurrence so that data between studies and missions can be compared. 20. Developing and maintaining a centralized catalogue of all written materials related to space and analog-environment biomedical research and experience accord- ing to current medical informatics standards. the spacecraft crew functions more autonomously, adapts to unexpected situations, and makes real-time decisions. ⢠NASA, because of its mission and history, has tended to be an insular organization dominated by traditional engineering. Because of the engineering problems associated with early space endeavors, the his- torical approach to solving problems has been that of engineering. Long- duration space travel will require a different approach, one requiring wider participation of those with expertise in divergent, emerging, and evolving fields. NASA has only recently begun to recognize this insuffi- ciency and to reach out to communities, both domestic and international, to gain expertise on how to remedy it. ⢠Engineering and biology are increasingly integrated at NASA, and this integration will be of benefit to the flexibility and control of long- duration missions into deep space. NASAâs structure does not, however, easily support the rapidly advancing integration of engineering and biol- ogy that is occurring throughout the engineering world outside NASA. NASA does not have a single entity that has authority over all aspects of astronaut health, health care, habitability, and safety that could facilitate integration of astronaut health and health care with engineering. ⢠The human being must be integrated into the space mission in the same way in which all other aspects of the mission are integrated. A comprehensive organizational and functional strategy is needed to coor- dinate engineering and human needs.
EMERGENCY AND CONTINUING CARE 135 Recommendation NASA should accelerate integration of its engineering and health sciences cultures. ⢠Human habitability should become a priority in the engineering aspects of the space mission, including the design of spacecraft. ⢠Investigators in engineering and biology should continue to ex- plore together and embrace emerging technologies that incorporate appropriate advances in biotechnology, nanotechnology, space wor- thy medical devices, âsmartâ systems, medical informatics, informa- tion technology, and other areas to provide a safe and healthy envi- ronment for the space crew. ⢠More partnerships in this area of integration of engineering and health sciences should be made with industry, academic institutions, and agencies of the federal government.
Mission Control, Johnson Space Center, Houston, Texas, during the early portion of space shuttle mission STS-95 on October 29, 1998, overlooking the Flight Director (FD) and the Spacecraft Communicator (CAPCOM) consoles. NASA image. Dr. Paul Stoner (left) and Dr. Jeff Jones, on-duty flight surgeons in Houstonâs Mission Control Center during the April 24, 2000, launch attempt of space shuttle Atlantis dur- ing mission STS-101. NASA image. 136
