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A new hydrostatic anti-G suit vs. a pneumatic anti-G system: preliminary comparison.
Aviat Space Environ Med. 2002 Jul; 73(7):703-8.AS

Abstract

HYPOTHESIS

A newly developed hydrostatic anti-G suit is now commercially available. The suit is said to offer a high level of protection against +Gz acceleration. However, past experience shows that it is difficult to produce a hydrostatic suit with effective high-G protection. Careful testing is, therefore, needed to verify its efficacy.

METHODS

The G-protective properties of the hydrostatic anti-G suit (Libelle; L) were compared with those of a pneumatic anti-G ensemble (AGE-39) used in the Swedish JAS 39 Cripen aircraft. Three pilots were studied during vertical (+Gz) acceleration in a centrifuge using the following: 1) the L-suit with varied straining maneuvers; 2) the AGE-39 in combination with full anti-G straining maneuvers (AGSM) throughout each high-G exposure (full maneuver; FM); and 3) the AGE-39 in combination with AGSM during the initial part of each high-G exposure (reduced maneuver; RM). G-intensity tolerance was established during exposures to rapid onset rate (ROR) profiles with G-plateau levels ranging from +6.0 to +9.0 Gz. G-endurance was studied during simulated aerial combat maneuvers (SACM) consisting of 10 cycles of 5.5 to 7.5 G.

RESULTS

All three pilots tolerated 9.0 G with the pneumatic system both in the RM and FM conditions; their tolerances averaged 6.3 G (range 6.0 to 7.0 G) for the L suit. Thus, during the ROR exposures only the 6.0 G profile was completed by all subjects in all three conditions. At this G-load both muscle straining (as indicated by electromyographic activity in thigh and abdomen) and heart rate were higher in the L than in the RM condition. Mean arterial pressure at eye level was higher in the FM than in the L and RM conditions. Only one subject was able to complete the SACM profile in the L condition. In the RM condition all subjects completed the SACM profile and in the FM condition two subjects completed the SACM.

CONCLUSIONS

Whether the AGE-39 was used in combination with maximal AGSM throughout the duration of each high-G exposure or with AGSM only during the initial part of the high-G exposure, G-intensity tolerance was 9.0 G. While wearing the L-suit, G-tolerance was 6.3 G. Thus, under the conditions tested, the G-protection afforded by the L-suit is not adequate for use in a 9-G aircraft.

Authors+Show Affiliations

Eiken O
Defence Research Agency, Karolinska Institutet, Stockholm, Sweden. ola.eiken@fyfa.ki.se
Kölegård R
No affiliation info available
Lindborg B
No affiliation info available
Aldman M
No affiliation info available
Karlmar KE
No affiliation info available
Linder J
No affiliation info available
Kölegoård R
No affiliation info available

MeSH

AccelerationAdaptation, PhysiologicalAdultAerospace MedicineAirBlood PressureCentrifugationElectromyographyEquipment DesignGravitationGravity SuitsHeart RateHumansMaleMilitary PersonnelOccupational ExposurePhysical EnduranceValsalva ManeuverWater

Pub Type(s)

Clinical Trial
Comparative Study
Controlled Clinical Trial
Journal Article

Language

eng

PubMed ID

12137110

Citation

Eiken, O, et al. "A New Hydrostatic anti-G Suit Vs. a Pneumatic anti-G System: Preliminary Comparison." Aviation, Space, and Environmental Medicine, vol. 73, no. 7, 2002, pp. 703-8.
Eiken O, Kölegård R, Lindborg B, et al. A new hydrostatic anti-G suit vs. a pneumatic anti-G system: preliminary comparison. Aviat Space Environ Med. 2002;73(7):703-8.
Eiken, O., Kölegård, R., Lindborg, B., Aldman, M., Karlmar, K. E., Linder, J., & Kölegoård, R. (2002). A new hydrostatic anti-G suit vs. a pneumatic anti-G system: preliminary comparison. Aviation, Space, and Environmental Medicine, 73(7), 703-8.
Eiken O, et al. A New Hydrostatic anti-G Suit Vs. a Pneumatic anti-G System: Preliminary Comparison. Aviat Space Environ Med. 2002;73(7):703-8. PubMed PMID: 12137110.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A new hydrostatic anti-G suit vs. a pneumatic anti-G system: preliminary comparison. AU - Eiken,O, AU - Kölegård,R, AU - Lindborg,B, AU - Aldman,M, AU - Karlmar,K E, AU - Linder,J, AU - Kölegoård,R, PY - 2002/7/26/pubmed PY - 2003/1/8/medline PY - 2002/7/26/entrez SP - 703 EP - 8 JF - Aviation, space, and environmental medicine JO - Aviat Space Environ Med VL - 73 IS - 7 N2 - HYPOTHESIS: A newly developed hydrostatic anti-G suit is now commercially available. The suit is said to offer a high level of protection against +Gz acceleration. However, past experience shows that it is difficult to produce a hydrostatic suit with effective high-G protection. Careful testing is, therefore, needed to verify its efficacy. METHODS: The G-protective properties of the hydrostatic anti-G suit (Libelle; L) were compared with those of a pneumatic anti-G ensemble (AGE-39) used in the Swedish JAS 39 Cripen aircraft. Three pilots were studied during vertical (+Gz) acceleration in a centrifuge using the following: 1) the L-suit with varied straining maneuvers; 2) the AGE-39 in combination with full anti-G straining maneuvers (AGSM) throughout each high-G exposure (full maneuver; FM); and 3) the AGE-39 in combination with AGSM during the initial part of each high-G exposure (reduced maneuver; RM). G-intensity tolerance was established during exposures to rapid onset rate (ROR) profiles with G-plateau levels ranging from +6.0 to +9.0 Gz. G-endurance was studied during simulated aerial combat maneuvers (SACM) consisting of 10 cycles of 5.5 to 7.5 G. RESULTS: All three pilots tolerated 9.0 G with the pneumatic system both in the RM and FM conditions; their tolerances averaged 6.3 G (range 6.0 to 7.0 G) for the L suit. Thus, during the ROR exposures only the 6.0 G profile was completed by all subjects in all three conditions. At this G-load both muscle straining (as indicated by electromyographic activity in thigh and abdomen) and heart rate were higher in the L than in the RM condition. Mean arterial pressure at eye level was higher in the FM than in the L and RM conditions. Only one subject was able to complete the SACM profile in the L condition. In the RM condition all subjects completed the SACM profile and in the FM condition two subjects completed the SACM. CONCLUSIONS: Whether the AGE-39 was used in combination with maximal AGSM throughout the duration of each high-G exposure or with AGSM only during the initial part of the high-G exposure, G-intensity tolerance was 9.0 G. While wearing the L-suit, G-tolerance was 6.3 G. Thus, under the conditions tested, the G-protection afforded by the L-suit is not adequate for use in a 9-G aircraft. SN - 0095-6562 UR - https://www.unboundmedicine.com/medline/citation/12137110/A_new_hydrostatic_anti_G_suit_vs__a_pneumatic_anti_G_system:_preliminary_comparison_ DB - PRIME DP - Unbound Medicine ER -