Yoann Gole

Diaphragmatic Motion Studied by M-Mode Ultrasonography: Methods, Reproducibility, and Normal Values

BACKGROUND Although diaphragmatic motion is readily studied by ultrasonography, the procedure remains poorly codified. The aim of this prospective study was to determine the reference values for diaphragmatic motion as recorded by M-mode ultrasonography. METHODS Two hundred ten healthy adult subjects (150 men, 60 women) were investigated. Both sides of the posterior diaphragm were identified, and M-mode was used to display the movement of the anatomical structures. Examinations were performed during quiet breathing, voluntary sniffing, and deep breathing. Diaphragmatic excursions were measured from the M-mode sonographic images. In addition, the reproducibility (inter- and intra-observer) was assessed. RESULTS Right and left diaphragmatic motions were successfully assessed during quiet breathing in all subjects. During voluntary sniffing, the measurement was always possible on the right side, and in 208 of 210 volunteers, on the left side. During deep breathing, an obscuration of the diaphragm by the descending lung was noted in subjects with marked diaphragmatic excursion. Consequently, right diaphragmatic excursion could be measured in 195 of 210 subjects, and left diaphragmatic excursion in only 45 subjects. Finally, normal values of both diaphragmatic excursions were determined. Since the excursions were larger in men than in women, the gender should be taken into account. The lower limit values were close to 0.9 cm for women and 1 cm for men during quiet breathing, 1.6 cm for women and 1.8 cm for men during voluntary sniffing, and 3.7 cm for women and 4.7 cm for men during deep breathing. CONCLUSIONS We demonstrated that M-mode ultrasonography is a reproducible method for assessing hemidiaphragmatic movement.

Original ResearchUltrasonographyDiaphragmatic Motion Studied by M-Mode Ultrasonography: Methods, Reproducibility, and Normal Values

BACKGROUND Although diaphragmatic motion is readily studied by ultrasonography, the procedure remains poorly codified. The aim of this prospective study was to determine the reference values for diaphragmatic motion as recorded by M-mode ultrasonography. METHODS Two hundred ten healthy adult subjects (150 men, 60 women) were investigated. Both sides of the posterior diaphragm were identified, and M-mode was used to display the movement of the anatomical structures. Examinations were performed during quiet breathing, voluntary sniffing, and deep breathing. Diaphragmatic excursions were measured from the M-mode sonographic images. In addition, the reproducibility (inter- and intra-observer) was assessed. RESULTS Right and left diaphragmatic motions were successfully assessed during quiet breathing in all subjects. During voluntary sniffing, the measurement was always possible on the right side, and in 208 of 210 volunteers, on the left side. During deep breathing, an obscuration of the diaphragm by the descending lung was noted in subjects with marked diaphragmatic excursion. Consequently, right diaphragmatic excursion could be measured in 195 of 210 subjects, and left diaphragmatic excursion in only 45 subjects. Finally, normal values of both diaphragmatic excursions were determined. Since the excursions were larger in men than in women, the gender should be taken into account. The lower limit values were close to 0.9 cm for women and 1 cm for men during quiet breathing, 1.6 cm for women and 1.8 cm for men during voluntary sniffing, and 3.7 cm for women and 4.7 cm for men during deep breathing. CONCLUSIONS We demonstrated that M-mode ultrasonography is a reproducible method for assessing hemidiaphragmatic movement.

Haemodynamic changes after prolonged water immersion

Abstract Thermoneutral water immersion increases cardiac preload and changes the neuroendocrine settings of blood volume regulation. The resulting marked diuresis may lead to significant haemodynamic changes after the end of a prolonged water immersion. Ten volunteers underwent 6 h of complete thermoneutral water immersion. Changes in cardiovascular status were assessed 1 h and 16 h after water immersion. Haemodynamic changes were assessed by Doppler echocardiography. Arterial wall distensibility was estimated by pulse wave velocity analysis. One hour after water immersion, mean weight loss was 1.78 kg and urine volume amounted to 1.5 litres. Echocardiographic measurements evidenced a significant decrease in dimensions of the left cardiac chambers and inferior vena cava. The decreased cardiac preload was paralleled by a lower stroke volume and cardiac output. A peripheral vasoconstriction associated with a relative decrease in the lower limb blood flow was evidenced by an increase in carotid-pedal pulse wave velocity and by a decrease in ankle brachial index. Sixteen hours after water immersion, cardiac preload and cardiac output remained below baseline values and peripheral vascular tone was still higher than at baseline. Marked haemodynamic changes had not returned to baseline 16 h after water immersion. There is a need to design fluid-replacement protocols to improve this recovery.

Combination of two oxidant stressors suppresses the oxidative stress and enhances the heat shock protein 27 response in healthy humans

We tested the hypothesis that the combination of 2 oxidant stressors (hyperoxia and fatiguing exercise) might reduce or suppress the oxidative stress. We concomitantly measured the plasma concentration of heat shock proteins (Hsp) that protect the cells against the deleterious effects of reactive oxygen species. Healthy humans breathed pure oxygen under normobaric condition for 50-minute periods during which they stayed at rest or executed maximal static handgrip sustained until exhaustion. They also repeated handgrip bouts in normoxic condition. We performed venous blood measurements of 2 markers of the oxidative stress (thiobarbituric acid reactive substances and reduced ascorbic acid) and Hsp27. Under normoxic condition, the handgrip elicited an oxidative stress and a modest increase in plasma Hsp27 level (+7.1 +/- 5.4 ng/mL). Under hyperoxic condition, (1) at rest, compared with the same time schedule in normoxic condition, we measured an oxidative stress (increased thiobarbituric acid reactive substances and decreased reduced ascorbic acid levels) and the plasma Hsp27 level increased (maximal variation, +12.5 +/- 6.0 ng/mL); and (2) after the handgrip, the oxidative stress rapidly disappeared. The combination of both hyperoxia and handgrip bout doubled the Hsp27 response (maximal variation, +24.8 +/- 9.2 ng/mL). Thus, the combination of 2 hits eliciting an oxidative stress seems to induce an adaptive Hsp27 response that might counterbalance an excessive production of reactive oxygen species.

A 5-month weight-reduction programme has a positive effect on body composition, aerobic fitness, and habitual physical activity of severely obese girls: A pilot evaluation study

Abstract In this pilot study, we wished to determine whether a 5-month multidisciplinary programme of a combined dietary-nutritional education-exercise intervention would have favourable effects on the health status of 18 obese adolescent girls. Before and after the clinical intervention, body composition and habitual physical activity were assessed by bioelectrical impedance and accelerometry, respectively. Aerobic fitness and substrate utilization were determined by gas exchange using an incremental field test that mimics habitual conditions. Despite a significantly (P < 0.001) greater loss of fat mass (−8.7 ± 4.1 kg) compared with fat-free mass (−2.8 ± 2.2 kg), energy expenditure at rest decreased by 9% following the intervention. Maximal oxygen consumption ([Vdot]O2max) related to fat-free mass increased by 7% (P < 0.05), whereas substrate utilization during exercise did not change following the intervention. Moderate and intense physical activity increased by 15% (+20 min · day−1; P < 0.05) and 45% (+25 min · day−1; P < 0.01), respectively. A significant relationship was observed between change in habitual physical activity and change in [Vdot]O2max/fat-free mass (r = 0.56, P = 0.01). The present multidisciplinary programme enhanced the loss of fat mass relative to fat-free mass but not sufficiently so to prevent a decline in metabolic rate during rest. Our results suggest a coupling in the improvement of aerobic fitness and habitual physical activity in obese adolescent girls, and hence an improvement in behaviour in relation to physical activity.

Specific diving training-induced arterial circulation changes

Objective: Several stressors such as cold water immersion, hyperoxic exposure and decompression-induced circulating bubbles can alter arterial circulation after a dive. The aim of this study was to investigate the arterial modifications induced by a specific diving training including repeated hyperbaric exposures and physical training. Method: Arterial pressure measurement and pulse wave velocity (PWV) recordings were performed in 12 student military divers before and after 15 weeks’ training. The results were compared with the same investigations performed in 12 non-diver healthy subjects. Results: A decrease in systolic blood pressure and pulse pressure was observed at both upper and lower limbs in student military divers after the training. Non-significant decreases in both carotido-femoral PWV and carotido-pedal PWV were found after the training. When the pulse time transit was divided by the cardiac cycle length between two R peaks ((RR) interval), a significant increase was observed between the carotid and femoral sensors. On the other hand, some differences were noticed between military divers and controls. Controls and divers were matched appropriately according to age and height, although the divers had a higher aerobic capacity as well as lower resting heart rate and lower pulse wave velocity. Conclusion: In trained military subjects, a training which includes repeated diving exposures and endurance exercises leads to vascular modifications suggesting an increase in central arterial compliance. There was no sign of arterial alteration induced by repeated diving exposures.

Fin swimming improves respiratory gas exchange.

Data in the literature suggest that compared to dry-land exercise fin swimming might delay the activation of the anaerobic metabolism. To verify this hypothesis, we explored indirect indices such as the oxygen pulse (VO(2)/HR), carbon dioxide production (VCO(2)), and ventilatory threshold, comparing fin swimming exercise to dry-land cycling. Thirteen participants, experienced or inexperienced in fin swimming, completed an incremental fin swimming exercise and a maximal exercise on a cycloergometer with breath-by-breath measurements of heart rate (HR), ventilation (VE), tidal volume (VT), VO(2), VCO(2), and VO(2)/HR and determination of the ventilatory threshold and maximal oxygen uptake (VO(2)max). Compared to dry-land cycling exercise, fin swimming resulted in elevated or absent ventilatory threshold. Although VO(2)max did not differ in either condition, in fin swimming the maximal HR value was lower (-18%, p=0.0072), maximal VO(2)/HR higher (+20%, p=0.0325), and maximal VCO(2) lower (-17%, p=0.0071). We also measured significant reduction of VE, VT, and HR variations for the same VO(2) increase. This study suggests that the anaerobic muscle metabolism might be delayed in fin swimming. An attenuated chemoreflex drive to the heart and respiratory centres exerted by muscle metabolites might explain the depressed cardiopulmonary response to fin swimming.

Military diving training improved arterial compliance.

This study was aimed at investigating whether repeated SCUBA diving might induce long term cardiovascular and autonomic modifications. In 11 military mine clearance diving students, arterial compliance (ultrasound scan study of brachial artery and ratio of stroke volume to pulse pressure: SV/PP), resting spectral analyses of heart rate and blood pressure variability, and a cold pressor test were performed before and after a 15-week military diving training course. After the diving training, arterial compliance was improved, as indicated by the significant increase in brachial arterial compliance (from 24+/-10 to 37+/-14 ml.mmHg (-1)) and SV/PP (from 1.7+/-0.2 to 1.9+/-0.2 ml.mmHg (-1)), and by the significant decrease in systolic, diastolic and pulse pressures (from 130+/-8 to 120+/-7; from 71+/-4 to 67+/-4; and from 58+/-8 to 53+/-5 mmHg, respectively). The peak oxygen uptake increased significantly from 54.3+/-2.0 to 56.8+/-4.0 mL.kg (-1).min (-1). Finally, the vasoconstrictive response during the cold pressor test increased (p<0.05). These findings point to a positive effect of a 15-week military diving training course on vascular function, and for a concomitant development of some peripheral vascular acclimatization to cold.

Arterial compliance in divers exposed to repeated hyperoxia using rebreather equipment.

BACKGROUND Acute hyperoxic exposure is known to modify cardiovascular parameters like a decrease in cardiac output, arterial vasoconstriction, and autonomic nervous system changes. We hypothesized that repeated hyperbaric hyperoxic exposures, as experienced by military oxygen divers, lead to long-term arterial alterations. METHODS Arterial blood pressure measurements and pulse wave velocity (PWV) recordings were performed during basal conditions in 15 elite military oxygen divers, and compared to 15 non-diver controls. The two groups were matched appropriately for physical characteristics (age: 35 +/- 5 yr, weight: 77 +/- 8 kg, height: 177 +/- 6 cm, body mass index: 24.6 +/- 2.0 kg x m(-2)), and aerobic capacity (VO2max : 52 +/- 7 ml x min(-1) x kg(-1)). RESULTS No significant difference was found in systolic blood pressure (120 +/- 11 mmHg), diastolic blood pressure (70 +/- 8 mmHg), or pulse pressure (50 +/- 7 mmHg). Furthermore, there was no significant difference in the carotid-femoral PWV (6.7 +/- 0.9 m x s(-1)), the carotid-radial PWV (8.7 +/- 1.7 m x s(-1)), or the carotid-pedal PWV (8.1 +/- 1.1 m x s(-1)) between divers and controls. CONCLUSION No difference in arterial compliance was observed in physically well-trained military oxygen divers in comparison with matched controls.

Valsalva maneuver-induced ptosis during water sports activities.

CASE REPORT A 49-year-old man carried out a scuba dive at 33-m depth during 40 minutes; the water temperature was 18 C. During the descent, after several Valsalva maneuvers to equalize middle ear and ambient pressures, he felt a left temporal pain. On exit from the water, he complained about a discomfort in the left eye. Clinical examination revealed an isolated, spontaneous, permanent, and moderate left ptosis with no oculomotor disorder or abnormal papillary reflex (Figure 1). Tonometry, Lancaster test, and examination of visual acuity and visual field were normal. The computed tomography scans showed a hyperdense and biconvex mass coupled with the orbital roof, which compressed the levator muscle of the upper eyelid (Figure 2). The magnetic resonance imaging (MRI) scans excluded a vascular malformation. The coagulation checkup was normal. The progression was quickly favorable with anti-inflammatory treatment leading to the disappearance of the ptosis in 10 days. After 6 weeks, MRI showed complete resolution of the hematoma. Six months after onset, he resumed diving and to date has completed more than 20 dives without complications or other disorders. DISCUSSION Valsalva maneuver may induce hemorrhagic ocular lesions including retinopathy, maculopathy, or orbital hematoma. The disorders are attributed to the circulatory changes induced by the maneuver, whereby forced expiration against the closed glottis leads to an increase in intrathoracic and central venous pressure. Venous return to the heart is decreased and peripheral venous pressure rises. The rise in intraocular venous pressure may result in rupture of capillaries. Valsalva maneuvers employed in various sports activities such as weight lifting, strength athletics, or aerobic exercise may lead to ocular lesions. During a dive, the Valsalva maneuver is used to equalize middle ear and ambient pressures during the descent to prevent middle ear barotrauma. In addition to the Valsalva maneuver, the hemorrhagic ocular lesions may also have been facilitated by the water immersion. Indeed, during immersion, the hydrostatic pressure limits the distension of the vessels with a flexible wall in the soft tissues, thereby redistributing blood toward the more rigid thoracic cage. The central venous pressure increases by at least 10 mm Hg in water immersion in comparison with ambient air. In our case, the ptosis observed after the dive was attributed to a subperiosteal hematoma. The absence of valves in the intraorbital veins facilitates transmission of this hyperpressure into the orbit. As the periosteum is weakly adherent, the subperiosteal veins may rupture. Nontraumatic subperiosteal orbital hemorrhage can induce a unilateral or bilateral ptosis with proptosis, a deviation of the ocular globe and a limitation of its elevation. Computed tomography scan or MRI is helpful to diagnose, localize, and follow up a causal orbital hematoma. In common with other case reports, the hematoma was located in the orbital roof of our patient. The treatment is generally medical, including antiedema drugs, anti-inflammatory drugs, and antiglaucomatous treatment. It should include correction of promoting factors such as vascular malformation, coagulopathy, or infection. Surgical drainage is indicated for patients with acute compression of the optic nerve. The course is usually