Increased elastic recoil as a determinant of pulmonary barotrauma in divers.

The elastic and conductive behaviour of the lungs were studied in sixteen divers during an interrupted deflation from total lung capacity (TLC.) The results in six divers, who had suffered pulmonary barotrauma (PBT) during shallow water diving, were compared with the findings in a control group of divers. Conductive behaviour and mean lung volumes were similar in the two groups. Compared with the control group, the PBT group had higher maximum transpulmonary pressures and a lower static pulmonary compliance, and deflated their lungs earlier. In relatively stiff lungs, an even distribution of elastance may increase susceptibility to barotrauma, because the more compliant zones are subjected to a greater strain. Pulmonary barotrauma appears to select from the total population of healthy divers those with lungs of decreased distensibility.     

Patent foramen ovale in scuba divers. A report of two cases and a brief review of the literature.

Scuba diving (diving with a self-contained underwater breathing apparatus) has become a popular sport. Decompression illness may be due to the formation of gas bubbles in various body tissues at an increased ambient pressure. The gas can pass from the systemic venous circulation into the arterial circulation as a result of either pulmonary barotrauma or intravascular shunting. Gas emboli may be the cause of an increased prevalence of brain lesions in sport divers. The management of scuba divers (professionals and amateurs) with a patent foramen ovale is not clear. We present the cases of 2 subjects with decompression illness and a patent foramen ovale and briefly review the literature on this combination.     

Value of Bronchial Challenge in Scuba Diving Candidates

Bronchial challenges were effected with carbachol in 76 subjects who were candidates for a scuba diving group. Bronchial reactivity was assessed through airway resistance and forced expiratory volume in 1 sec (FEV₁) measurements. Medical interrogation had revealed symptoms of recent (RA) or ancient (AA) asthma, or allergic rhinitis (AL). Nearly half of the subjects (47%) presented bronchial hyperresponsiveness (BHR), which was much more frequent in the RA group, but whose strength did not depend on clinical presentation. Prevalence of BHR was fairly high (36%) in the AL group. BHR constituted a contraindication to scuba diving because it may promote pulmonary barotrauma.     

Value of Bronchial Challenge in Scuba Diving Candidates

Bronchial challenges were effected with carbachol in 76 subjects who were candidates for a scuba diving group. Bronchial reactivity was assessed through airway resistance and forced expiratory volume in 1 sec (FEV₁) measurements. Medical interrogation had revealed symptoms of recent (RA) or ancient (AA) asthma, or allergic rhinitis (AL). Nearly half of the subjects (47%) presented bronchial hyperresponsiveness (BHR), which was much more frequent in the RA group, but whose strength did not depend on clinical presentation. Prevalence of BHR was fairly high (36%) in the AL group. BHR constituted a contraindication to scuba diving because it may promote pulmonary barotrauma.     

Diving: what to tell the patient with asthma and why?

Until a decade ago, divers with asthma were uniformly barred from diving with compressed air. This prohibition was based more on theoretical concerns for barotrauma than on actual data. Follow-up studies, although retrospective, do not support a ban on recreational or commercial diving for divers with stable asthma. These studies have noted that, despite the prohibition on diving, many divers with asthma have logged multiple dives without negative consequences. When those who have suffered diving-related barotrauma have undergone physiologic testing, measurements of small airways dysfunction (maximal mid-expiratory flow rates) have been lower than measurements for comparable divers who have never suffered diving accidents. Follow-up studies with long-term commercial divers have shown that a small percentage of individuals who have sufferred diving-related barotrauma also develop abnormal maximal mid-expiratory flow rates and even some airway hyperreactivity. These latter findings correlate with the changes that occur in chronic asthmatic patients, especially those who are not well treated. The decision as to whether an asthmatic patient should be allowed to dive rests on the individual's physiologic function, maturity, and insight into the consequences of poorly managed airway inflammation and bronchospasm.     

Diffuse alveolar hemorrhage temporally related to cocaine smoking

Previous reports of respiratory complications from cocaine abuse have focused on pulmonary barotrauma or a reduction in carbon monoxide diffusing capacity. We report a patient who developed life-threatening alveolar hemorrhage following repeated inhalation of alkaloid cocaine.     

Lightning injury with lung bleeding in a tracheotomized patient

A 68-year-old man, who had undergone laryngectomy six months earlier, was struck by lightning and developed pulmonary hemorrhage. This was attributed to pulmonary barotrauma due to a lightning blast via his tracheostoma.     

Clinical and tympanometric findings in repeated recreational scuba diving

BACKGROUND: Due to the condition known as middle ear squeeze, scuba diving has become one of the main causes of barotrauma, and the acute form of this condition has been relatively well established. However, there are few reports available on clinical or laboratory findings in divers who practise repeated diving. The objective of the present study was to assess the otological effects of repeated dives. METHOD: This was an observational study conducted on 19 recreational scuba divers, considered to be experienced divers according to the criteria established by the Professional Association of Dive Instructors (PADI). These divers undertook four dives per day on five consecutive days, and their tympanic membranes were assessed using tympanometry and otoscopy. Data were analysed using the chi(2)-test for trend. The level of statistical significance was set at p<0.05 in all analyses. RESULTS: The findings suggest that multiple scuba dives over a short period of time cause damage to the structures of the ear, as evidenced by the tympanometric and otoscopic findings, which revealed cumulative effects of pressure against the tympanic membrane and within the middle ear. This condition was not observed when surface intervals exceeded 11h. CONCLUSIONS: The results suggest that extending surface intervals may offer protection against middle ear barotrauma in recreational scuba diving.     

A review of the respiratory effects of smoking cocaine

A variety of pulmonary complications related to the use of freebase cocaine have been reported in the medical literature. Pulmonary barotrauma, hypersensitivity pneumonitis, pulmonary hemorrhage, obliterative bronchiolitis, asthma, and pulmonary edema have all recently been described. The number of reports are few, reflecting either the low incidence of these complications or the lack of recognition of these phenomena as cocaine-related illnesses. The mechanism by which freebase cocaine can injure the lung is not well defined. Whether an abnormal immunologic response to cocaine freebase can result in hemorrhage, pneumonitis, bronchiolitis, or asthma remains speculative. Whether cardiogenic or non-cardiogenic factors play a role in the development of pulmonary edema in freebase smokers has not yet been determined. Likewise, the roles of either cocaine, tobacco, or adulterants in producing the observed abnormalities of lung function remain controversial. Further reporting of freebase-related pulmonary complications, as well as the development of appropriate animal models, is needed.     

Ten years of diving-related illness in the Royal Navy

The period from 1 January 1980 to 31 December 1989 produced a total of 244 training and operational diving accident reports involving Royal Navy and Royal Marines personnel. Because the incidence figures fluctuated widely year by year, a clear trend over the decade failed to emerge. However, the incidence of Type II decompression sickness, as a percentage of total decompression sickness, was greater in the second half of the decade than in the first, a trend similar to, although more moderate than, recent experience of dysbaric illness amongst sport divers. Student divers were disproportionately highly represented in the statistics, particularly with regard to pulmonary barotrauma and near-drowning.     

Recreational scuba diving, patent foramen ovale and their associated risks

Scuba diving has become a popular leisure time activity with distinct risks to health owing to its physical characteristics. Knowledge of the behaviour of any mixture of breathable gases under increased ambient pressure is crucial for safe diving and gives clues as to the pathophysiology of compression or decompression related disorders. Immersion in cold water augments cardiac pre- and afterload due to an increase of intrathoracic blood volume and peripheral vasoconstriction. In very rare cases, the vasoconstrictor response can lead to pulmonary oedema. Immersion of the face in cold water is associated with bradycardia mediated by increased vagal tone. In icy water, the bradycardia can be so pronounced, that syncope results. For recreational dives, compressed air (i.e., 4 parts nitrogen and 1 part oxygen) is the preferred breathing gas. Its use is limited for diving to 40 to 50 m, otherwise nitrogen narcosis ("rapture of the deep") reduces a diver's cognitive function and increases the risk of inadequate reactions. At depths of 60 to 70 m oxygen toxicity impairs respiration and at higher partial pressures also functioning of the central nervous system. The use of special nitrogen-oxygen mixtures ("nitrox", 60% nitrogen and 40% oxygen as the typical example) decreases the probability of nitrogen narcosis and probably bubble formation, at the cost of increased risk of oxygen toxicity. Most of the health hazards during dives are consequences of changes in gas volume and formation of gas bubbles due to reduction of ambient pressure during a diver's ascent. The term barotrauma encompasses disorders related to over expansion of gas filled body cavities (mainly the lung and the inner ear). Decompression sickness results from the growth of gas nuclei in predominantly fatty tissue. Arterial gas embolism describes the penetration of such gas bubbles into the systemic circulation, either due to pulmonary barotrauma, transpulmonary passage after massive bubble formation ("chokes") or cardiac shunting. In recreational divers, neurological decompression events comprise 80% of reported cases of major decompression problems, most of the time due to pathological effects of intravascular bubbles. In divers with a history of major neurological decompression symptoms without evident cause, transoesophageal echocardiography must be performed to exclude a patent foramen ovale. If a cardiac right-to-left shunt is present, we advise divers with a history of severe decompression illness to stop diving. If they refuse to do so, it is crucial that they change their diving habits, minimising the amount of nitrogen load on the tissue. There is ongoing debate about the long term risk of scuba diving. Neuro-imaging studies revealed an increased frequency of ischaemic brain lesions in divers, which do not correlate well with subtle functional neurological deficits in experienced divers. In the light of the high prevalence of venous gas bubbles even after dives in shallow water and the presence of a cardiac right-to-left shunt in a quarter of the population (i.e., patent foramen ovale), arterialisation of gas bubbles might be more frequent than usually presumed.     

An autopsy case of adult respiratory distress syndrome (ARDS) with peculiar histopathological features modified by a positive end-expiratory pressure (PEEP) therapy

A case is reported of adult respiratory distress syndrome(ARDS) combined with barotrauma due to positive end-expiratory pressure (PEEP) therapy. The patient was a 32-year-old woman with fulminant hepatitis, type B, who died of ARDS 22 days after the onset of the illness. The autopsy revealed extraordinary heavy lungs (left: 923g, right: 985g) with edema in the peripheral part and marked emphysematous changes in the central part near the hili. Histologically, scattered foci of intra-alveolar organization and interstitial fibrosis with hemorrhage were observed, which might have been the result of the proceeding pneumonia. The emphysematous lesion seen in this case was peculiar and not like any type of of ordinary pulmonary emphysema. Judging from the strange, sharply demarcated emphysematous lesion with marked destruction of alveolar structure, and the good preservation of the alveolar structure in the edematous lesion, the emphysematous lesion might be barotrauma which was induced by PEEP therapy on top of pneumonia.     

Prenatal Nicotine Exposure and Pulmonary Barotrauma of Newborns

Smoking in adults increases the relative risk of contracting spontaneous pneumothorax, a form of pulmonary barotrauma. Maternal smoking habits affect the fetus. Pregnant females attend the antenatal clinic at the 8th to 12th weeks of pregnancy. There is a participation rate of 99% of all births in Sweden. Their smoking habits were registered at this stage. This study supported the hypothesis that the registered maternal smoking habits covariated with the risk of contracting pulmonary barotrauma in newborn infants. The infants of smokers do not seem to be at higher risk (95% C.I. of RR: 0.78–0.99) for contracting pulmonary barotrauma than those of nonsmokers. Thus far, the hypothesis is even rejected at the 5% significance level. However, after considering other factors, especially mothers education, it seems to be an open question whether or not a weak covariation is present. Newborn boys run almost twice the risk of contracting pulmonary barotrauma than girls. Furthermore, we found an increased risk for contracting pulmonary barotrauma in the subcohort of newborns whose mothers smoking habits were not reported.     

Decreased pulmonary distensibility and pulmonary barotrauma in divers.

Pulmonary distensibility, lung volume and conductance were measured in 14 men (mean age 22 (SD 3) years) who suffered pulmonary barotrauma (PBT) during shallow water diving. Exponential analysis of static pressure-volume date obtained during deflation of the lungs gave K, and index of distensibility. The pulmonary conductance-recoil pressure (GL-PL) relationship was also obtained during deflation. Total lung capacity (TLC) was measured in a body plethysmograph or by nitrogen washout. The results were compared with 34 male nonsmokers and 10 healthy male divers. Mean lung volumes and FEV1 did not differ significantly in the three groups. In the PBT group K was decreased and recoil pressure was increased; the slope of the regression of GL and PL was decreased indicating stiffer airways. Decreased K reflects a decreased airspace size. Smaller airspaces increase the surface component of recoil pressure which increases the stress in tissue fibres. Relatively stiff airways may magnify the elastic stresses in peribronchial alveolar tissue increasing the possibility of rupture of alveolar walls with interstitial gas dissection.     

High-Resolution Computed Tomographic Findings of Cocaine-Induced Pulmonary Disease: A State of the Art Review

Cocaine is the most commonly used illicit drug among patients presenting at hospital emergency departments and the most frequent cause of drug-related deaths reported by medical examiners. Various respiratory problems temporally associated with cocaine use have been reported. Acute and chronic uses also are responsible for lung complications, such as pulmonary edema, alveolar hemorrhage, pulmonary hypertension, organizing pneumonia, emphysema, barotrauma, infection, cancer, eosinophilic disease, and aspiration pneumonia. Although most imaging findings are nonspecific, they may raise suspicion of a cocaine-related etiology when considered together with patients’ profiles and medical histories. This literature review describes cocaine-induced diseases with pulmonary involvement, with an emphasis on high-resolution chest computed tomographic findings and patterns.     

肺占位穿刺基于CT评估肺出血风险的临床研究

目的 对肺占位病灶行CT引导下经皮肺穿刺活检(CT-guided percutaneous transthoracic needle biopsy,PTNB),利用CT评估肺出血风险的危险因素.方法 对行PTNB的1174例患者(1226个病灶)进行回顾性分析.通过对患者信息、病灶特征、穿刺情况、病理结果等相关影响因素...     

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.     

Selective fiberoptic left main-stem intubation for severe unilateral barotrauma in a 24-week premature infant

A 24-week premature infant developed severe right-sided pulmonary barotrauma secondary to mechanical ventilation for respiratory distress syndrome (RDS). High-frequency oscillatory ventilation and permissive hypercapnia were initiated. A chest tube was placed to relieve a pneumothorax, and a catheter was inserted into an air-filled cyst for drainage. These maneuvers failed to improve the child's respiratory status. The child's left main-stem bronchus was then successfully fiberoptically intubated for single-lung ventilation in order to reduce the unilateral barotrauma. Single-lung ventilation was effectively and safely continued for 5 days, with complete resolution of the pulmonary barotrauma.     

Guidelines of the Spanish Society of Cardiology for car driving, airplane flying,and underwater activities in subjects with heart disease

Car driving, airplane piloting and underwater activities by subjects with heart disease may cause sudden incapacitation leading to the loss of the safety margins necessary to avoid accidents. In the case of car driving and airplane piloting the risk affects, not only the driver or pilot, but also passengers and/or bystanders within an accident zone. In the case of diving the risk resides basically in the loss of control of the vital support mechanisms necessary in a very hostile medium. This document reviews the possible causes of unexpected incapacitation, with or without loss of consciousness, in the light of the pathophysiologic consequences of fatigue, hypoxia, stress or barotrauma posed by each activity. Detailed recommendations are made for limiting driving, piloting and diving, based on official Spanish and European regulations and the addresses of specialized centers are provided for consultation. Moreover, recommendations for airplane travel for patients with heart disease are indicated.     

A Case Report of an Elderly Woman With Thrombocytopenia and Bilateral Lung Infiltrates: A Rare Association Between Diffuse Alveolar Hemorrhage and Idiopathic Thrombocytopenic Purpura

Etiologies for diffuse alveolar hemorrhage are wide and range from infectious to vasculitis and malignant processes. Idiopathic thrombocytopenic purpura is an autoimmune disorder characterized by persistent thrombocytopenia, with a relatively indolent course in young patients, but a more complicated progression and high associated mortality in the older patients. Diffuse alveolar hemorrhage, complicating idiopathic thrombocytopenic purpura, is a very uncommon association, with only 2 reported cases in the literature. We present a 69-year-old healthy woman presenting with petechial rash, progressive dyspnea, and bilateral alveolar infiltrates. She was found to have idiopathic thrombocytopenic purpura associated with diffuse alveolar hemorrhage. The patient had an excellent response to high doses of pulse steroids and immunoglobulins.A high index of suspicion for noninfectious pulmonary diseases should be considered in patients with autoimmune diseases presenting with pulmonary infiltrates and hypoxia. Flexible bronchoscopy with sequential lavage is a relatively safe procedure in patients with coagulopathy and should be attempted to detect and confirm the diagnosis; absence of hemoptysis should not preclude the diagnosis.