Selected scientific publications on diving medicine and physiology.

2005 Mar 6
Pulpal and periodontal temperature rise during KTP laser use as a root planing complement in vitro
Nammour, Rocca JP, Keiani K, Balestra C, Snoeck T, Powell L, Reck JV.

The purpose of this study was to define the optimal irradiation conditions of a KTP laser during root planing treatment. METHODS: The surfaces of 60 single-root human teeth were scaled with conventional instruments before lasing. The pulpal temperature increase was measured by means of one thermocouple placed in the pulp chamber and a second one placed on the root surface at 1 mm from the irradiation site. The influence of variables of coloration by Acid Red 52 (photosensitizer), scanning speed, dentin thickness, and probe position was analyzed for a constant exposure time of 15 sec and 500 mw (spot size diameter, 0.5 mm). The pulpal temperature was below 3 degrees C for the adjustments.

Read more

2016 Feb 14
Serum erythropoietin levels in healthy humans after a short period of normobaric and hyperbaric oxygen breathing: the "normobaric oxygen paradox"
Balestra C, Germonpré P, Poortmans JR, Marroni A.

Renal (peritubular) tissue hypoxia is a well-known physiological trigger for erythropoietin (EPO) production. We investigated the effect of rebound relative hypoxia after hyperoxia obtained under normo- and hyperbaric oxygen breathing conditions. A group of 16 healthy volunteers were investigated before and after a period of breathing 100% normobaric oxygen for 2 h and a period of breathing 100% oxygen at 2.5 ATA for 90 min (hyperbaric oxygen). Serum EPO concentration was measured using a radioimmunoassay at various time points during 24-36 h. A 60% increase (P < 0.001) in serum EPO was observed 36 h after normobaric oxygen. In contrast, a 53% decrease in serum EPO was observed at 24 h after hyperbaric oxygen. Those changes were not related to the circadian rhythm of serum EPO of the subjects. These results indicate that a sudden and sustained decrease in tissue oxygen tension, even above hypoxia thresholds (e.g., after a period of normobaric oxygen breathing), may act as a trigger for EPO serum level. This EPO trigger, the "normobaric oxygen paradox," does not appear to be present after hyperbaric oxygen breathing.

Read more

2007 Nov 30
Effect of varying deep stop times and shallow stop times on precordial bubbles after dives to 25 msw (82 fsw)
Bennett PB1, Marroni A, Cronje FJ, Cali-Corleo R, Germonpre P, Pieri M, Bonuccelli C, Leonardi MG, Balestra C.

In our previous research, a deep 5-min stop at 15 msw (50 fsw), in addition to the typical 3-5 min shallow stop, significantly reduced precordial Doppler detectable bubbles (PDDB) and "fast" tissue compartment gas tensions during decompression from a 25 msw (82 fsw) dive; the optimal ascent rate was 10 msw (30 fsw/min). Since publication of these results, several recreational diving agencies have recommended empirical stop times shorter than the 5 min stops that we used, stops of as little as 1 min (deep) and 2 min (shallow). In our present study, we clarified the optimal time for stops by measuring PDDB with several combinations of deep and shallow stop times following single and repetitive open-water dives to 25 msw (82 fsw) for 25 mins and 20 minutes respectively; ascent rate was 10 msw/min (33 fsw). Among 15 profiles, stop time ranged from 1 to 10 min for both the deep stops (15 msw/50 fsw) and the shallow stops (6 msw/20 fsw). Dives with 2 1/2 min deep stops yielded the lowest PDDB scores--shorter or longer deep stops were less effective in reducing PDDB. The results confirm that a deep stop of 1 min is too short--it produced the highest PDDB scores of all the dives. We also evaluated shallow stop times of 5, 4, 3, 2 and 1 min while keeping a fixed time of 2.5 min for the deep stop; increased times up to 10 min at the shallow stop did not further reduce PDDB. While our findings cannot be extrapolated beyond these dive profiles without further study, we recommend a deep stop of at least 2 1/2 mins at 15 msw (50 fsw) in addition to the customary 6 msw (20 fsw) for 3-5 mins for 25 meter dives of 20 to 25 minutes to reduce PDDB.

Read more

2009 Apr 5
Safety of recreational scuba diving in type 1 diabetic patients: the Deep Monitoring programme
Bonomo M1, Cairoli R, Verde G, Morelli L, Moreo A, Grottaglie MD, Brambilla MC, Meneghini E, Aghemo P, Corigliano G, Marroni A.

To verify whether, with thorough practical and theoretical training, well-controlled, non-complicated diabetic patients can safely go diving underwater with no additional medical or metabolic risks. METHODS: Twelve diabetic patients participated in the study after undergoing training focused on their diabetic status. Two dives per day were scheduled during two five-day stays on the island of Ventotene (Italy). Capillary blood glucose (BG) was checked at 60, 30 and 10 minutes before diving, and corrective measures adopted if necessary, based on BG absolute levels and dynamics. A device for continuous subcutaneous glucose monitoring (CGM), expressly modified for the purpose, was worn during dives.

Read more

2009 Mar 3
Preventive effect of pre-dive hydration on bubble formation in divers
Gempp E, Blatteau JE, Pontier JM, Balestra C, Louge P.

OBJECTIVE: To investigate whether prehydration 90 min before a dive could decrease bubble formation, and to evaluate the consequent adjustments in plasma volume (PV), water balance and plasma surface tension (ST).

Read more