Cerebral blood velocity and other cardiovascular responses to 2 days of head-down tilt.

Spaceflight induces a cephalad redistribution of fluid volume and blood flow within the human body, and space motion sickness, which is a problem during the first few days of spaceflight, could be related to these changes in fluid status and in blood flow of the cerebrum and vestibular system. To evaluate possible changes in cerebral blood flow during simulated weightlessness, we measured blood velocity in the middle cerebral artery (MCA) along with retinal vascular diameters, intraocular pressure, impedance cardiography, and sphygmomanometry on nine men (26.2 +/- 6.6 yr) morning and evening for 2 days during continuous 10 degrees head-down tilt (HDT). When subjects went from seated to head-down bed rest, their heart rate and retinal diameters decreased, and intraocular pressures increased. After 48 h of HDT, blood flow velocity in the MCA was decreased and thoracic impedance was increased, indicating less fluid in the thorax. Percent changes in blood flow velocities in the MCA after 48 h of HDT were inversely correlated with percent changes in retinal vascular diameters. Blood flow velocities in the MCA were inversely correlated (intersubject) with arterial pressures and retinal vascular diameters. Heart rate, stroke volume, cardiac output, systolic arterial pressure, and at times pulse pressure and blood flow velocities in the MCA were greater in the evening. Total peripheral resistance was higher in the morning. Although cerebral blood velocity is reduced after subjects are head down for 2 days, the inverse relationship with retinal vessel diameters, which have control analogous to that of cerebral vessels, indicates cerebral blood flow is not reduced.

A retrospective study of promethazine and its failure to produce the expected incidence of sedation during space flight.

Since March 1989, intramuscular (IM) promethazine has been successfully used to treat the symptoms of space motion sickness. The incidence of sedation associated with promethazine administration on the ground is large and may result in operational impact. The authors undertook a retrospective study to quantify the incidence of sedation from promethazine use during Space Shuttle flights. Crew medical debriefings from 14 shuttle missions were reviewed for crew members who had been treated with IM promethazine and their corresponding symptoms were identified. Twenty-one crew members received IM promethazine (25-50 mg), and only one experienced any associated sedation with no operational impact. This sedation incidence of less that 5% is in stark contrast to the 60 to 73% incidence of sedation seen in ground-based studies. The incidence of sedation during space flight from IM promethazine is substantially less than that seen on the ground and does not present an operational problem during Space Shuttle flights. Future investigations of environmental stressors and pharmacodynamic changes associated with space flight may explain the huge disparity between the space-flight and ground-based data.

Comparison of parachute landing injury incidence between standard and low porosity parachutes.

Deployment of personnel by parachute is a common practice in many types of operations, both in and out of the military. Such operations are not without hazard and are associated with injuries which commonly occur during the landing phase of deployment. Environmental factors (i.e., wind and terrain) together with parachute sink rate are thought to influence the incidence of landing injuries. This study compared the incidence of overall landing injury and landing injury by parachute type in 8,706 jumps over 3 years between 1988 and 1990 between a standard porosity round canopy and a lower sink rate low porosity round canopy. In all cases the low porosity parachute group experienced significantly (p = 0.007) fewer overall injuries and fewer injuries of every type (reductions of 77% in 1988, 81% in 1989, and 94% in 1990). Reduction of sink rate by even small amounts correlates with significant (p less than 0.001) injury incidence reductions on the basis of reduced kinetic energy dissipation. Low porosity parachutes should be adopted where appropriate to reduce sink rate and hence landing injuries. Flight surgeons associated with airborne operations and who are familiar with these data can play a significant role in reducing parachute landing injuries.

Overhead and forward reach capability during exposure to +1 to +6 Gx loads.

The lack of reach performance data obtained under space-flight conditions has led to questions regarding the operational impact of higher G loads on crew performance. This investigation studied the effect of increasing G loads on reach capability. Ten subjects were exposed in a stepwise fashion to increasing accelerations resulting in G loads of from +1 to +6 Gx in the Brooks AFB centrifuge. Four subjects wore the pre-Challenger Launch Entry Helmet (LEH) ensemble and six the current Launch Entry Suit (LES). The subjects performed standardized reach sweeps at each G level. These sweeps were recorded on videotape and subsequently analyzed using a 3-dimensional motion analysis system. Significant differences in forward and overhead reach were determined using the General Linear Models (GLM) procedure of the Statistical Analysis System (SAS) program. The results from this study suggest that purposeful movement can be realistically performed in the LEH at the 5 G level and in the LES up to the 4 G level.

Insidious hypothermia during raft use.

It is commonly thought that increasing protection against cold water results in greater physiological efficiency in maintaining core temperature. To examine the relationship of physiological changes resulting from cold exposures as a function of increased insulation, five subjects (4 males, 1 female) wearing anti-exposure ensembles covering the entire body and head were exposed in a pool to water temperatures (Twater) = 4.4 degrees C and air temperatures (Tair) = 5.6 degrees C. Trials consisted of subjects undergoing either head-out immersions with mean exposure time (t = 150 +/- 9 S.E.M. min) or enclosed within a raft (t = 398 +/- 126 min). Rectal temperatures were higher, and their relative change from baseline (delta Tre) smaller, for 3 of the 5 subjects at minute 122 in the water than in the raft. While no correlation was found between mean weighted skin temperature (Tsk), hand temperature (Thand), or foot temperature (Tfoot) with Tre, close correlation was found between delta Tre and forehead temperature (Tfore) (r = 0.97, p less than 0.05) and change in forehead temperature (r = 0.97, p less than 0.05). The results suggest that, during cold exposure, increased insulation, under specific conditions, may result in a lower Tre.

Effectiveness of the Space Shuttle anti-exposure system in a cold water environment.

The purpose of this study was to evaluate the National Aeronautics and Space Administration (NASA) Space Shuttle Launch Entry Suit (LES) and raft for 24 h of protection against cold water immersion. Two configurations, the LES and the LES with raft (Navy LRU-18/U with NASA spray shield) were evaluated for anti-exposure protection. Conditions were selected to simulate worst case water and air temperatures along projected Space Shuttle ground tracks; i.e., water temperatures = 4.4 degrees C (40 degrees F), air temperature = 5.6 degrees C (42 degrees F), 1 foot waves (chop), and constant spray. Four males, 31-44 years of age, and one 32-year-old female, were studied once in each configuration. Trials with and without a raft were scheduled for up to 24 and 6 h, respectively. Mean LES trial durations were 150 +/- 9 min and final rectal temperature (Tre, f) = 36.5 +/- 0.3 degrees C. Mean LES with raft (LES/r) trial durations were 398 +/- 126 min and final rectal temperature (Tre, f) = 35.6 +/- 0.4 degrees C. LES and LES/r trials were terminated for reaching Tre = 35.0 degrees C or subject-requested termination due to discomfort. The longest LES and LES/r trials were terminated due to subject discomfort. Although not achieving the desired durations, the LES and LES/r did prove capable of protecting individuals, respectively, for up to 3 and 13.5 h. Since the longest LES and LES/r runs were terminated due to subjective tolerance and not physical incapacitation, actual survival times greater than 3 and 13.5 h, respectively, could be expected for individuals in these ensembles.

Comparison of current Shuttle and pre-Challenger flight suit reach capability during launch accelerations.

The Challenger accident prompted the creation of a crew escape system which replaced the former Launch Entry Helmet (LEH) ensemble with the current Launch Entry Suit (LES). However, questions were raised regarding the impact of this change on crew reach capability. Our study addressed the question of reach capability and its effect on realistic ground-based training for Space Shuttle missions. Eleven subjects performed reach sweeps in both the LEH and LES suits during 1 and 3 Gx acceleration trials in the Brooks AFB, TX, centrifuge. These reach sweeps were recorded on videotape and subsequently analyzed using a three-dimensional motion analysis system. The ANOVA procedure of the Statistical Analysis System (SAS) program was used to evaluate differences in forward and overhead reach. The results showed that the LES provided less reach capability than its predecessor, the LEH. This study also demonstrated that, since there was no substantial difference between 1 and 3 Gx reach sweeps in the LES, realistic Shuttle launch training may be accomplished in ground-based simulators.

Musculoskeletal injury review in the U.S. space program.

Astronauts in NASA's space program are expected to remain fit to complete their on-orbit tasks and to function effectively in the event of contingency operations. Due to the generally self-directed exercise program and reliance on competitive sports and running for conditioning, plus limited emphasis on training techniques and rehabilitation, there have been a surprising number of orthopedic injuries and surgeries in this small adult population. This article examines the orthopedic injury history of U.S. astronauts during the period from 1987-95. The type of injury, activity involved, and subsequent surgical interventions are cataloged. There were a total of 26 fractures, 36 serious ligament, cartilage, or soft tissue injuries, and 28 orthopedic surgical procedures in this adult group with a mean astronaut corps size of only 94. Women accounted for 16% of the study population but accounted for only 1 of 28 surgical procedures. Knee injuries required surgical intervention 19 times. Running, skiing, and basketball were most frequently associated with injuries. The descriptive data regarding frequency of adverse events and activity associated with injuries is presented. These injury patterns are analyzed and suggestions made for future improvement, including decreased reliance on running and competitive athletics for conditioning, improved personal fitness training preflight, and coordinated rehabilitation postflight. Also recommended is the use of a lap pool for preflight total body fitness training, since swimming provides conditioning to those muscle groups used during spaceflight, and for variably weighted gravity rehabilitation postflight.

The "Space Cycle" Self Powered Human Centrifuge: a proposed countermeasure for prolonged human spaceflight.

The Self Powered Human Centrifuge, or Space Cycle, is a countermeasure to the adverse physiologic effects of prolonged human exposure to spaceflight microgravity. This unique device simultaneously provides exercise, impact loading and gravity analogous acceleration to emulate conditions on Earth. One or two crewmembers pedal themselves about a shaft mounted to the space craft located "above" their heads. This creates a short arm centrifuge with a head-to-toe acceleration orientation. The potential advantages of the Space Cycle include: a) reversal of cephalad fluid shift, minimizing post flight orthostatic intolerance; b) pedaling to maintain muscular and cardiovascular fitness; and c) enhancement of skeletal homeostasis by impact loading with a pedal-crank mounted cam and frame mounted resistive device. Other anticipated advantages include generation of usable electricity, physiologic monitoring and a means of mass measurement. Motion sickness is controlled with restraints and virtual reality headsets. The device is compatible with International Space Station dimensional constraints.

Treatment efficacy of intramuscular promethazine for space motion sickness.

Intramuscular promethazine and its efficacy in the treatment of Space Motion Sickness (SMS) were evaluated using standardized questions administered during postflight debriefings to crewmembers immediately after their first Shuttle flight. Space Motion Sickness was graded as none, mild, moderate, or severe, based on published criteria. Immediate symptom relief (within 1-2 h) was evaluated by subjective reports; medication efficacy was based on scores derived from the four most frequently reported symptoms of SMS: nausea, vomiting, loss of appetite, and stomach awareness. Scores were given for each symptom, mild = 1, moderate = 2, and severe = 3, and added for a total score for each flight day. Following intramuscular (IM) promethazine on flight day 1, the scores were used to determine if the crewmembers were "sick" or "not sick" on flight day 2. On the basis of the scoring criteria, any subject with a score adding to greater than three, with any severe symptom, or with vomiting was defined as "sick." The comparison showed that 25% of crewmembers treated with IM promethazine were "sick" on flight day 2, compared to 50% of crewmembers who did not receive promethazine (p = 0.046). Of crewmembers treated with IM promethazine, 90% reported immediate symptom relief as well. Untreated crewmembers typically have slow symptom resolution over 72-96 h, and those treated with oral scopolamine/dextroamphetamine show delayed symptom development. This study suggests that intramuscular promethazine is an effective treatment for SMS and merits continued use and further controlled investigations.

Sex differences in operating room care giver perceptions of patient safety: a pilot study from the Veterans Health Administration Medical Team Training Program.

BACKGROUND: Achieving a culture of safety is believed to be an important mechanism for improving patient safety. The Safety Attitudes Questionnaire (SAQ) measures provider perceptions of patient safety culture across six domains; higher scores denote more positive perceptions. Although professional differences on the SAQ have been explored, sex differences have not. METHODS: The SAQ was administered to operating room (OR) care givers at nine Department of Veterans Affairs hospitals. We determined the mean domain scores by care giver profession and sex, used analysis of variance to compare mean scores across professions, used t tests to compare mean scores between sexes and created regression models of the six patient safety domains. RESULTS: The SAQ was completed by 187 OR care givers. Older care givers were significantly more likely to report favourable perceptions of teamwork climate; surgeons were significantly more likely to report favourable perceptions of working conditions; anaesthesia providers were significantly more likely to report favourable perceptions of stress recognition but also less favourable perceptions of safety climate. Women were significantly more likely to report less favourable perceptions of job satisfaction and working conditions. CONCLUSION: This pilot study confirms previously reported profession differences in OR care giver patient safety attitudes. We also found previously unreported sex differences. Educational efforts designed to enhance patient safety should be designed so that they address such differences.

Comparing measures of patient safety for inpatient care provided to veterans within and outside the VA system in New York.

CONTEXT: Previous studies have compared measures of patient safety for veterans using the VA system to the general population. Discrepancies in the results of those studies suggest that the choice of an appropriate comparison group is critical for accurate interpretation of results and for determining whether to take actions to address findings. We explored another method of providing consumer information by comparing the experiences of VA enrolled patients who received care in the VA to those who received care outside the VA system. OBJECTIVE: For male veterans living in New York State and enrolled in the VA healthcare system, to determine (a) whether those who obtain care outside the VA system experience different measures of patient safety than those treated within the VA system, and (b) whether cross-system comparisons of measures of patient safety among older veterans reflect those of the full age spectrum. DESIGN: Retrospective cohort analysis. SETTING: All VA and non-VA hospitals in New York State. PATIENTS: 353,570 male New York State residents who were enrolled in the VA system in 1998, 1999 or 2000. MAIN OUTCOME MEASURES: The Agency for Healthcare Research and Quality (AHRQ) has developed Patient Safety Indicators (PSIs) from hospital discharge data. To standardise these indicators across settings, AHRQ has provided software for risk-adjustment purposes so that the indicators can be compared across settings of care. We used the PSI software to calculate risk-adjusted PSI rates with 95% confidence intervals to compare veterans' inpatient care provided within and outside the VA system. RESULTS: Risk-adjusted rates for nine of 15 PSIs did not differ between care provided within and outside the VA system. However, compared with care provided outside the VA system, risk-adjusted rates of decubitus ulcer, postoperative sepsis, infection due to medical care, postoperative respiratory failure and postoperative metabolic derangement occurred at lower rates within the VA system, while death in low mortality DRGs occurred at a higher rate in the VA system. Findings for patients aged 65 and older were similar to those of the entire age spectrum. CONCLUSIONS: Using AHRQ's PSI software, male veterans in New York who obtain their inpatient care within the VA received care that was comparable with or somewhat better than those who obtained their inpatient care outside the VA. The experiences of older patients reflected those of younger patients. Given that our findings are much more similar to reported comparisons between the VA and Medicare than to comparisons between the VA and the general population, we conclude that, should system comparisons be made, choice of comparison groups will be critical to accurate interpretation of findings; however, prior to such interpretation, the validity of the PSIs must be determined within VA.

Patient safety--the VA's experience.

An overarching principle of medicine is "First Do No Harm." Indeed, as the Institute of Medicine recently highlighted, without safety, there is no quality. The Veterans Health Administration of the Department of Veterans Affairs (VA), the nation's largest integrated health system, has made a commitment to safe patient care. Programmatic responsibility for supporting this commitment resides in the National Center for Patient Safety (NCPS).

Developing a culture of safety in the Veterans Health Administration.

CONTEXT: Weaving patient safety into the fabric of clinical activities is an increasingly important aspect of medical care. OBJECTIVE: To detail the steps taken by the Veterans Health Administration (VHA) to integrate patient safety into its organizational structure. DESIGN: Descriptive study. SETTING: VHA. DATA SOURCES: VHA documents, congressional testimony, the medical literature, the general press, and personal communications. RESULTS: The VHA leadership has taken steps to promote a culture of safety by making public commitments to improving patient safety, allocating resources toward establishment of special centers, enhancing employee education on patient safety, and providing incentives to promote safety. The VHA is also establishing one mandatory and one voluntary adverse event reporting system; in the latter case, the reporter remains anonymous. Examples of nationally mandated initiatives are bar coding of all medications and use of computerized medical record that includes order entry, laboratory and imaging results, and all encounter notes. CONCLUSIONS: The VHA's initial efforts may serve as a template for other health care organizations that wish to engineer a culture of safety. Although progress has been made, patient safety efforts require constant attention to guard against becoming a new bureaucracy or simply window dressing.

Developing a culture of patient safety at the VA.

Patient safety is a topic that has become prominent in the minds of many, both within and outside the healthcare field over the past several months. But in fact, literature in medical journals describing this topic goes back decades. However, studying these issues is only the first step towards developing useful and practical tools to address errors and does little to change the safety culture that underlies these systems. The VA has taken several steps towards a safety culture and the development and implementation of tools, such as: 1) error reporting mechanisms; 2) tools for root cause and corrective action; and 3) management tools (e.g., safety awards).

Developing and deploying a patient safety program in a large health care delivery system: you can't fix what you don't know about.

BACKGROUND: The Veterans Administration (VA) identified patient safety as a high-priority issue in 1997 and implemented the Patient Safety Improvement (PSI) initiative throughout its entire health care system. In spring 1998 the External Panel on Patient Safety System Design recommended alternative methods to enhance reporting and thereby improve patient safety. REDESIGNING THE PSI INITIATIVE: The VA began redesigning the PSI initiative in late 1998. The dedicated National Center for Patient Safety (NCPS) was established. Using the panel's recommendations as a jumping-off point, NCPS began to identify known and suspected obstacles to implementation (such as possible punitive consequences and additional workload). NCPS adopted a prioritization scoring method, the Safety Assessment Code (SAC) Matrix, for close calls and adverse events, which requires assessing the event's actual or potential severity and the probability of occurrence. The SAC Matrix specifies actions that must be taken for given scores. Use of the SAC score permits a consistent handling of reports throughout the VA system and a rational selection of cases to be considered. A system for performing a root cause analysis (RCA) was developed to guide caregivers at the frontline. This system includes a computer-aided tool, a flipbook containing a series of six questions, and reporting of the findings back to the reporter. The final step requires that the facility's chief executive officer "concur" or "nonconcur" on each recommended corrective action. The RCA team outlines how the effectiveness of the corrective action will be evaluated to verify that the action has had the intended effect, and it ascertains that there were no unintended negative consequences. IMPLEMENTATION: Based on successful implementation in two pilots, full-scale national rollout to the 173 facilities began in April 2000 and was concluded by the end of August 2000. NCPS supplied 3 days of training for individuals at each facility. The training included didactic components, an introduction to human factors engineering concepts, and small- and large-group simulation exercises. Facility leaders were reminded of the necessity to reinforce the point that assignment to an RCA team was considered an important duty. DISCUSSION: It is essential to design and implement a system that takes into account the concerns of the frontline personnel and is aimed at being a tool for learning and not accountability. The system must have as its primary focus the dissemination of positive actions that reduce or eliminate vulnerabilities that have been identified, not a counting exercise of the number of reports.