Evaluation of the effects of hyperbaric oxygen treatment and enoxaparin on left colon anastomosis. An experimental study.

BACKGROUND: Surgical interventions on left colon lead to high morbidity. The problems in wound healing are the main cause of this morbidity. Hypoxia retards wound healing and hyperbaric oxygen treatment (HBOT) has an anti-hypoxic effect. MATERIALS AND METHODS: In this experimental study we divided eighty Wistar albino rats into eight groups and numbered between 1 and 8. Normal (non-ischemic) and ischemic left colon anastomosis were performed in the first and second four groups respectively. HBOT and subcutaneous enoxaparin were applied to the groups separately and in combination for four days, except the control groups. (Group-1 and Group-5). We measured anastomotic bursting pressures and performed pathological examinations besides electron microscopic study in one sample from each group after sacrificing the rats on the fourth day. RESULTS: There were no statistically significant differences in bursting pressures when we compared Group-1 with other non-ischemic groups, and Group-5 with Group-6, but there were statistically significant differences when we compared Group-5 with Group-7 and 8. In pathological examination, there were no statistically significant differences between the groups concerning necrosis, epithelization, granulation tissue formation and collagen deposition. Statistically significant differences were found in the scores of neovascularization when we compared Group-1 with Group-3 and 4, and Group-5 with Group-8. Electron microscopic evaluation revealed a prominent increase both in neovascularization and collagen fibers in the samples taken from the groups received enoxaparine and hyperbaric oxygen treatment in combination. CONCLUSIONS: These findings suggest that HBOT increases neovascularization and bursting pressures in ischemic colon anastomosis in contrast with enoxaparin.

Should computed chest tomography be recommended in the medical certification of professional divers? A report of three cases with pulmonary air cysts.

Pulmonary barotrauma (PBT) is a recognised risk of compressed gas diving. Any reason that causes air trapping in the lung during ascent may cause PBT by increasing intrapulmonary pressure. Chest x ray examination is mandatory for medical certification of the professional divers in many countries, but pulmonary air trapping lesions such as an air cyst in the lungs cannot always be detected by plain chest x ray examination. Computed tomography (CT) is a reliable, but expensive measure for detecting pulmonary abnormalities in divers. Three cases with pulmonary air cysts are reported in which air cysts were invisible on the x ray pictures, but well defined by CT. It is impractical and not cost effective to perform CT for medical certification of all divers, but it can be an option to recommend CT once during the initial examination of the candidates for professional diving, especially if there is a history of predisposing factors, such as smoking or pulmonary infections.

Ventilatory and metabolic response to rebreathing the expired air in the snorkel.

The snorkel, which allows swimmers to keep their face down in the water while breathing, is widely used by divers, spear fishermen and monofin swimmers. A snorkel adds an additional dead space of 160-170 ml and causes an increase in the concentration of CO2 in the inspired gas due to expired air trapped in the snorkel which is then re-inspired. In this study the metabolic and the ventilatory response to rebreathing the expired air in the snorkel were investigated in twelve human subjects. A 2900 C Sensor Medics gas analyzer was used in breath-by-breath mode for the measurements. Ventilation (VE), respiratory rate (RR), tidal volume (TV), oxygen consumption (.VO 2) and carbon dioxide production (.VCO 2) were measured at rest and during light exercise both with and without the snorkel dead space. We observed a significant increase in all variables except RR, when subjects rebreathed the gas in the snorkel. The increase in ventilation resulted from an increase in tidal volume rather than increasing respiratory rate. We conclude that the work of breathing is increased when CO2 concentration is high in inspired gas and re-breathing while snorkelling can be prevented by a new snorkel design with a low-resistance two-way non-rebreathing valve, which will allow the expired air flow into the water.

Hemoptysis provoked by voluntary diaphragmatic contractions in breath-hold divers.

Pulmonary barotrauma of descent (lung squeeze) has been described in breath-hold divers when the lung volume becomes smaller than the residual volume (RV), with the effect of increased ambient pressure. However, the ratio between the total lung capacity and the RV is not the only factor that plays a role in the lung squeeze. Blood shift into the thorax is another important factor. We report three cases of hemoptysis in breath-hold divers who dove for spear fishing in shallower depths than usual. All of the divers performed voluntary diaphragmatic contractions at the beginning of their ascent, while their mouths and noses were closed. We suggest that the negative intrathoracic pressure due to the forced attempt to breathe in with voluntary diaphragmatic contractions contributes to alveolar hemorrhage, since it may damage the pulmonary capillaries.

Dysbaric osteonecrosis in Turkish sponge divers.

Skeletal radiographs were performed to determine the prevalence of dysbaric osteonecrosis (DON) in 51 Turkish sponge divers. DON was correlated with the diver's age and experience, maximum diving depth, and decompression sickness (DCS). Thirty-six of the 51 divers had radiographic evidence of one or more lesions, for a prevalence of 70.6% DON. Proximal humerus was the most effected site. Type B (head, neck, and shaft) lesions were most common, comprising 63.6% of all DON lesions. Type A (juxta-articular) lesions were observed in all 10 divers who complained of painful motion of their shoulder or hip joints. DON most commonly affected the proximal humerus. Reportedly, 38 of these 51 (74.5%) divers had experienced DCS. We did not fnd any significant relationship between DON and DCS, maximum diving depth, diving experience, and divers' age.

Hyperbaric oxygen therapy in adriamycin extravasation: an experimental animal study.

Adriamycin extravasation is a serious problem that can lead to severe local necrosis and damage to underlying nerves, tendon, and muscle. There are some experimental studies in which conflicting results were reported about the beneficial effects of hyperbaric oxygen (HBO) in adriamycin-induced skin lesions. In this study the effect of HBO on the healing of adriamycin-induced wounds was investigated in the Wistar-Albino rat model. Ninety-five rats underwent injection of a 0.7-ml adriamycin solution (2 mg per milliliter) subcutaneously on the right upper hind legs. The HBO group (n = 43) received HBO treatment (at 2.5 ATA for 80 minutes) twice a day for 28 days. The control group (n = 42) did not receive any therapy. Lesion size was measured for 4 weeks. There was no significant difference in lesion size between the groups on days 7 (p = 0.1364) and 14 (p = 0.1123), but the lesion size was significantly smaller in the HBO group than in the control group on days 21 (p = 0.0251) and 28 (p = 0.0001). Of 36 animals with lesions in the HBO group, complete wound healing occurred in 16 animals by day 40. However, there was no complete wound healing in any of the 36 animals with lesions in the control group. The beneficial effect of HBO in adriamycin-induced skin lesions was observed in this experimental study.