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Jan Risberg

Publications and source records attributed to Jan Risberg.

7 recordsLinked to original sources
PubMed2004

Atmospheric changes and physiological responses during a 6-day "disabled submarine" exercise.

BACKGROUND: Survival time within a disabled submarine (SUBSUNK) is dependant on atmospheric composition and proper design and use of emergency atmospheric control systems. The objective of this study was to investigate atmospheric changes and physiological responses during a SUBSUNK trial. METHODS: There were 18 volunteers who were restrained within a 250 m3 front compartment of an Ula-class submarine submerged in 8 degrees C seawater for 6 d, 18 h. Atmospheric control was maintained according to emergency procedures using non-electrically powered chemical CO2 absorption, and O2 was replenished using chlorate candles. Atmospheric parameters, skin and body temperatures, weight, urine, and drinking volume were measured. Subjective responses to cold were measured on a visual analog scale (VAS), and symptoms were logged on the environmental symptoms questionnaire (ESQ). RESULTS: Atmospheric temperature gradually decreased to a minimum of 14.1 degrees C. Toe, heel, and finger temperatures decreased significantly. Subjects reported inferior subjective thermal comfort on the VAS and increased cold stress on the ESQ. Except for CO2, no inorganic or volatile organic compounds exceeded occupational exposure limits. The PO2 and PCO2 ranged from 17.4-20.3 and 1.9-2.8 kPa, respectively, during the first 5 d. During the last 2 d, PO2 and PCO2 were deliberately maintained at about 15.8 and 3.1 kPa, respectively. Mean oxygen consumption and CO2 production were 23.8 and 19.8 L standard temperature and pressure (STP) x man(-1) x h(-1), respectively. Soda lime and lithium hydroxide CO2 absorption capacities were 126 and 405 L STP x kg(-1) respectively. CONCLUSIONS: Atmospheric conditions can be controlled acceptably for 6 d, 18 h within the front compartment of an Ula-class submarine operating according to emergency SUBSUNK procedures.

Adult↗
PubMed2004

Stress and coping in a week-long disabled submarine exercise.

BACKGROUND: Emotional stress could impair cognitive performance and decision-making in the initial period within a disabled submarine (SUBSUNK). The aim of the present study was to explore stress reactions over time in submarine crewmembers exposed to a simulated SUBSUNK trial. METHODS: There were 18 Norwegian sailors who were confined within the front section of a conventional diesel-electric submarine for 6 d 18 h complying with emergency SUBSUNK procedures. Self-reported measures of habitual coping and personality hardiness were completed before the simulation, and measures of emotional stress symptoms and quality of life were assessed daily during the exercise and at 2 wk after the exercise. RESULTS: A repeated measures analysis of variance showed that emotional stress symptoms declined [F (6,14) = 2.76, p < 0.05], while quality of life improved over time [F (6,14) = 4.00, p < 0.01] from the first day compared with subsequent days of the experiment. Personality hardiness was negatively associated with emotional stress (r = -0.52) and lower quality of life (r = -0.47), while avoidant coping was positively associated with lower quality of life (r = 0.53) in the first 24 h of the SUBSUNK situation (all p < 0.05). CONCLUSIONS: These findings suggest that the level of emotional stress was highest in the first 24-h period, and that the level of distress was related to scores on personality hardiness and personality traits. These data have possible implications for selection and healthcare of personnel, and also suggest that crews will benefit from external help especially in the first 24 h of emergency response techniques.

Adaptation, Physiological↗
PubMed2003

Self-reported headache during saturation diving.

INTRODUCTION: Some commercial divers have claimed that headache is a frequent symptom related to decompression following a saturation dive, but due to lack of systematic reporting there is limited knowledge of the incidence and clinical characteristics of such headaches. METHODS: During 2001, a questionnaire was distributed to divers participating in offshore saturation diving operations on the Norwegian continental shelf. Two major diving contractors participated. The survey allowed anonymous self-reporting of past and present problems with headache; pain intensity was indicated daily on a visual analog scale (VAS) from 0 to 10. Of 95 divers, 56 participated and 67 saturations were registered. RESULTS: The divers estimated a higher frequency of headaches in connection to saturation diving than in everyday life (p < 0.001). One third of the divers reported experiencing headache after they finished decompression. There was a significant increase in reports of headache on the last day of decompression (p = 0.03) and on the first day post-saturation (p < 0.001) compared with the start of decompression. Median headache duration was 6 h (range 1-84 h) and median pain score estimated on a VAS was 2.5 (range 0.1-7.8), equivalent to moderate intensity. CONCLUSIONS: Headache incidence is greater in divers during saturation diving than in everyday life. The increase is correlated to the last phase of decompression and the post-saturation period. No specific cause(s) of the headache could be identified, but we discuss possible explanations.

Adult↗
PubMed2003

Balance testing and Doppler monitoring during hyperbaric exposure.

BACKGROUND: The effects on the postural system of saturation diving to shallow and medium depths have not previously been adequately tested. The purpose of this study was to investigate whether postural function is affected by a moderate hyperbaric exposure, and whether any deterioration is correlated with the presence of intravascular bubbles. HYPOTHESIS: Postural control and the vestibulo-ocular reflex are not affected during heliox saturation diving to 5 meters of seawater (msw). At greater depths, an effect may occur. METHODS: Postural control was tested with the subjects standing on a static balance platform before, during, and after onshore experimental saturation chamber dives to 5 msw heliox, 20 msw air, and to 100 msw heliox. Standard caloric testing with electronystagmography was performed before and after the heliox dives. Cardiac ultrasound and Doppler monitoring were used to detect possible venous gas emboli (VGE) during decompression in the heliox dives. RESULTS: During the heliox exposure to 5 msw, no significant change in body sway was found. However, a significant change in body sway was found during an air dive to 20 msw and during the 100 msw heliox exposure. Caloric responses were unchanged immediately post-dive. After decompression from 5 msw, VGE were detected in two divers. During the 100 msw exposure, one case of VGE was observed. CONCLUSIONS: Exposure to hyperbaric heliox conditions corresponding to 5 msw, did not influence postural control significantly, while exposure to 100 msw heliox, and air diving to 20 msw, did. Although VGE were detected in the heliox dives, we could not find any correlation between this observation and postural instability.

Adult↗
PubMed2002

Postural control and venous gas bubble formation during hypobaric exposure.

BACKGROUND: Earlier studies have shown that acute hypoxia at simulated altitudes up to 18,000 ft affects postural control. The main objective of this study was to investigate whether this is caused by hypoxia or by other effects of reduced barometric pressure. Doppler monitoring was included to rule out venous gas emboli (VGE) as a possible cause of disturbed postural control. A secondary objective was to evaluate two conventional altitude chamber training profiles regarding release of VGE. HYPOTHESIS: Chamber flights up to 18,000 ft affect postural control due to acute hypoxia or other effects of reduced barometric pressure such as bubble formation. VGE probably will not be formed at the altitude chamber flight profiles and procedures selected for this study. METHODS: Repeated registrations of postural control and Doppler monitoring for detection of possible VGE were performed on 12 subjects before, during, and after exposure to two different altitude chamber flight profiles. In chamber flight profile 1 the subjects were first preoxygenated for 45 min and then exposed to a normoxic environment at altitudes of 25,000, 18,000, 14,000, and 8000 ft. Chamber flight profile 2 consisted of an 80 min exposure to 14,000 ft without preoxygenation or supplemental oxygen for the first 60 min. RESULTS: In chamber flight profile 1, where normoxic conditions were achieved during all balance testing, no significant changes in postural control were found. No VGE were observed and no subjective dizziness was reported during this exposure. In chamber flight profile 2, a significant influence on postural control was reported for the eyes-open condition, when breathing air at 14,000 ft. These changes normalized when reaching ground level. VGE were observed in one of the 12 subjects after 75 min at 14,000 ft. Another subject complained of severe dizziness during the initial part of the decompression to 14,000 ft, and was excluded from further experiments. CONCLUSIONS: Changes in postural control at altitudes up to 18,000 ft is probably due to acute hypoxia. VGE may form during acute altitude exposure to 14,000 ft.

Adult↗