Extraterrestrial resuscitation of hemorrhagic shock: fluids.
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Aerospace Medicine↗
Biomedical subjects
M R Campbell
Publications and source records attributed to M R Campbell.
Prospective evaluation of thoracic ultrasound in the detection of pneumothorax.
BACKGROUND: Thoracic ultrasound may rapidly diagnose pneumothorax when radiographs are unobtainable; the accuracy is not known. METHODS: We prospectively evaluated thoracic ultrasound detection of pneumothorax in patients at high suspicion of pneumothorax. The presence of "lung sliding" or "comet tail" artifacts were determined in patients by ultrasound before radiologic verification of pneumothorax by residents instructed in thoracic ultrasound. Results were compared with standard radiography. RESULTS: There were 382 patients enrolled; the cause of injury was blunt (281 of 382), gunshot wound (22 of 382), stab wound (61 of 382), and spontaneous (18 of 382). Pneumothorax was demonstrated on chest radiograph in 39 patients and confirmed by ultrasound in 37 of 39 patients (95% sensitivity); two pneumothoraces could not be diagnosed because of subcutaneous air; the true-negative rate was 100%. CONCLUSION: Thoracic ultrasound reliably diagnoses pneumothorax. Expansion of the focused abdominal sonography for trauma (FAST) examination to include the thorax should be investigated for terrestrial and space medical applications.
Humans↗
Ultrasound evaluation of the magnitude of pneumothorax: a new concept.
Pneumothorax is commonly seen in trauma patients; the diagnosis is confirmed by radiography. The use of ultrasound where radiographic capabilities are absent, is being investigated by the National Aeronautics and Space Administration. We investigated the ability of ultrasound to assess the magnitude of pneumothorax in a porcine model. Sonography was performed on anesthetized pigs in both ground-based laboratory (n = 5) and microgravity conditions (0 x g) aboard the KC-135 aircraft during parabolic flight (n = 4). Aliquots of air (50-100 cm3) were introduced into the chest to simulate pneumothorax. Results were videorecorded and digitized for later interpretation. Several distinct sonographic patterns of partial lung sliding were noted including the combination of a sliding zone with a still zone and a "segmented" sliding zone. These "partial lung sliding" patterns exclude massive pneumothorax manifested by a complete separation of the lung from the parietal pleura. In 0 x g, the sonographic picture is more diverse; one x g differences between posterior and anterior aspects are diminished. Modest pneumothorax can be inferred by the ultrasound sign of "partial lung sliding." This finding, which increases the negative predictive value of thoracic ultrasound, may be attributed to intermittent pleural contact, small air spaces, or alterations in pleural lubricant. Further studies of these phenomena are warranted.
Animals↗
Surgical instrument restraint in weightlessness.
BACKGROUND: Performing a surgical procedure during spaceflight will become more likely in the future as the duration of missions becomes longer. Only minimal surgical capability was available on previous missions since the definitive medical care time was short and the likelihood of a surgical event too low to justify carrying surgical hardware onboard. Early demonstrations of surgical procedures in the microgravity environment of parabolic flight indicated the need for careful logistical planning and restraint of surgical hardware. Human ergonomics also has more effect in microgravity than in the conventional 1-G environment. METHODS: Three methods of surgical instrument restraint--a Minor Surgical Kit (MSK), a Surgical Restraint Scrub Suit (SRSS), and a Surgical Tray (ST)--were evaluated in parabolic flight surgical procedures. RESULTS: The MSK was easily stored, easily deployed, and demonstrated the best ability to facilitate a surgical procedure in microgravity. CONCLUSION: Important factors in a surgical restraint system for microgravity include excellent organization of supplies, ability to maintain sterility, accessibility while providing secure restraint, ability to dispose of sharp items and biological trash, and ergonomic efficiency.
Aerospace Medicine↗
Candidate mutator genes in mismatch repair-deficient thymic lymphomas: no evidence of mutations in the DNA polymerase delta gene.
DNA mismatch repair (MMR) proteins recognize nucleotides that are incorrectly paired. Deficiencies in MMR lead to increased genomic instability reflected in an increased mutation frequency and predisposition to tumorigenesis. Mice lacking the MMR gene, Msh2, develop thymic lymphomas that exhibit much higher mutational frequencies than other Msh2(-/-) tumours and Msh2(-/-) normal thymic tissue, suggesting that an additional mutator may have been acquired in a tissue-specific manner. Clustered mutations observed exclusively in the thymic lymphomas suggests that a gene(s) associated with the replication machinery might have become altered during tumorigenesis. Based on mutation studies in Saccharomyces cerevisiae lacking Msh2 and DNA polymerase delta (DNA pol delta), we hypothesized that the acquisition of mutations in DNA pol delta could contribute to the hypermutator phenotype and tumorigenesis in Msh2(-/-) thymic tissue. Furthermore, previous reports have suggested that genes containing mononucleotide repeats are non-random mutational targets in the absence of MMR. Therefore, we sequenced all 26 exons of the DNA pol delta catalytic subunit, including the six exons containing mononucleotide repeats of >5 bp, from nine Msh2(-/-) thymic lymphomas and two wild-type controls. No DNA pol delta pathogenic mutations were found in the thymic lymphomas, although several DNA base differences compared with published DNA pol delta sequences were observed. We conclude, therefore, that inactivating mutations in DNA pol delta are not a contributing factor in the development of the hypermutator phenotype in MMR-deficient murine thymic lymphomas.
Animals↗
Surgical care in space.
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Adaptation, Physiological↗
Blunt trauma and operative care in microgravity: a review of microgravity physiology and surgical investigations with implications for critical care and operative treatment in space.
BACKGROUND: The assembly of the International Space Station in a low earth orbit will soon become a reality. The National Aeronautics and Space Administration envisions inhabited lunar bases and staffed missions to Mars in the future. Increasing numbers of astronauts, construction of high-mass structures, increased extra-vehicular activity, and prolonged if not prohibitive medical evacuation times to earth underscore the need to address requirements for trauma care in nonterrestrial environments. STUDY DESIGN: A search was carried out to review the relevant literature in the MEDLINE and SPACELINE databases. All related Technical, Corporate, and Flight Test Reports in the KRUG Life Sciences corporate library were also reviewed. Bibliographies of all articles were then reviewed from these papers to identify additional pertinent literature. Senior Russian investigators reviewed the Russian literature and translated Russian publications when appropriate. Personal communication and discussion with active microgravity investigators and ongoing microgravity research supplemented published reports. RESULTS: A large volume of data exist to document the multiple detrimental physiologic effects of microgravity exposure on human physiology. Organs systems such as cardiovascular, neurohumoral, immune, hematopoetic, and musculoskeletal systems may be particularly affected. These physiologic changes suggest an impaired ability to withstand major systemic trauma. Observational data also suggest adverse changes in numerous aspects of response to wounding and injury, and in areas such as the behavior of hemorrhage, microbiologic flora, and wound healing. In addition to an increased volume of ongoing and anticipated basic science research in microgravity physiology, preliminary studies of clinical diagnosis and therapy have been carried out in microgravity and microgravity laboratories. The feasibility of a wide range of ancillary critical care techniques has been verified in the parabolic flight model of microgravity. Although Russian investigators first performed laparotomies on rabbits in parabolic flight in 1967, only recently have American investigators demonstrated the reproducible feasibility of open and endoscopic surgical procedures under general anesthetic in animal models in a microgravity environment. CONCLUSIONS: With appropriate instrumentation and personnel, the majority of resuscitative and surgical interventions required to stabilize a severely injured astronaut are feasible in a microgravity environment. Onboard limitations in mass, volume, and power that are ever present in any spacecraft design will limit the realistic capabilities of the medical system. Standard proved and tested trauma and operative management protocols will constitute the basis for extra-terrestrial care. Surgeons should familiarize themselves with the microgravity environment and remain active in planning trauma care for the continued exploration of space.
Aerospace Medicine↗
Laparoscopic surgery in weightlessness.
BACKGROUND: Performing a surgical procedure in weightlessness has been shown not to be any more difficult than in a 1g environment if the requirements for the restraint of the patient, operator, and surgical hardware are observed. The feasibility of performing a laparoscopic surgical procedure in weightlessness, however, has been questionable. Concerns have included the impaired visualization from the lack of gravitational retraction of the bowel and from floating debris such as blood. METHODS: In this project, laparoscopic surgery was performed on a porcine animal model in the weightlessness of parabolic flight. RESULTS: Visualization was unaffected due to the tethering of the bowel by the elastic mesentery and the strong tendency for debris and blood to adhere to the abdominal wall due to surface tension forces. CONCLUSIONS: There are advantages to performing a laparoscopic instead of an open surgical procedure in a weightless environment. These will become important as the laparoscopic support hardware is miniaturized from its present form, as laparoscopic technology becomes more advanced, and as more surgically capable crew medical officers are present in future long-duration space-exploration missions.
Abdomen↗
Surgical bleeding in microgravity.
A surgical procedure performed during space flight would occur in a unique microgravity environment. Several experiments performed during weightlessness in parabolic flight were reviewed to ascertain the behavior of surgical bleeding in microgravity. Simulations of bleeding using dyed fluid and citrated bovine blood, as well as actual arterial and venous bleeding in rabbits, were examined. The high surface tension property of blood promotes the formation of large fluid domes, which have a tendency to adhere to the wound. The use of sponges and suction will be adequate to prevent cabin atmosphere contamination with all bleeding, with the exception of temporary arterial droplet streams. The control of the bleeding with standard surgical techniques should not be difficult.
Animals↗
Animal surgery in microgravity.
The first surgical procedure in microgravity using an animal model is described. The investigation resulted in a realistic evaluation of prototype hardware and procedures that could be applied to a surgical support system on Space Station Freedom. This was especially true for the issue of the management of surgical bleeding, which was observed and studied in microgravity for the first time.
Animals↗
A review of microgravity surgical investigations.
The likelihood of performing a surgical procedure in space will increase as the Soviet Mir space station is expanded and the Space Station Freedom becomes operational. A review of previous research and hardware development, performed mostly in parabolic flight both in the Soviet Union and the U.S., reveals an interest in surgical chambers to prevent cabin atmosphere contamination. Surgical techniques appear to be no more difficult than in a 1-G environment if a restraint system is used. Minimizing the chances of wound infection from the high particle count spacecraft atmosphere is an additional concern. Additional research is necessary to delineate the clinical significance of these problems and to further develop surgical techniques in microgravity.
Aerospace Medicine↗