INTRODUCTION: After repetitive deep dives, breath-hold divers are often affected by a syndrome characterized by typical symptoms such as cough, sensation of chest constriction, blood-striated expectorate (hemoptysis) and, rarely, an overt acute pulmonary edema syndrome, often together with various degrees of dyspnea. The aim of this work is an epidemiological investigation to evaluate the prevalence of acute respiratory symptoms (ARS) in breath-hold divers (BHDs) in practicing breath-hold diving.

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).

Many competitive breath-hold divers use dry apnoea routines to improve their tolerance to hypoxia and hypercapnia, varying the amount of prior hyperventilation and lung volume. When hyperventilating and exhaling to residual volume prior to starting a breath-hold, hypoxia is reached quickly and without too much discomfort from respiratory drive. Cerebral hypoxia with loss of consciousness (LOC) can easily result. Here, we report on a case where an unsupervised diver used a nose clip that is thought to have interfered with his resumption of breathing after LOC. Consequently, he suffered an extended period of severe hypoxia, with poor ventilation and recovery.

Background and Objectives: The use of closed-circuit rebreathers (CCRs) in recreational diving is gaining interest. However, data regarding its physiological effects are still scarce. Immersion, cold water, hyperoxia, exercise or the equipment itself could challenge the cardiopulmonary system.

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.