Working safely under pressure: Field experience in occupational medicine Dr. med. Claudia Pletscher Suva, Department of Occupational Medicine Head of Preventative Occupational Medicine Sector
Agenda Introduction Health hazards Preventative occupational medicine Practical experience Seite 2
Weinberg Tunnel, Zurich Bypass Tunnel, Biel Allmend Tunnel, Lucerne Lac d'hongrin Seite 3
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Hydro-shield tunnelling Tunnel boring machines are in wide use The front section is secured by a shield, cross-section corresponds to the tunnel profile personnel are only used in exceptional cases, employees exposed for a short time Seite 6
TBM with hydro-shield 1) Rotating cutter 2) Working chamber 3) Pressure wall 4) Personnel airlock 5) Hydro-shield 6) Drive unit 7) Segment 8) Completed terrain Seite 7
Tunnelling: Cut-and-cover method Use in low depth and loose subsoil Comparatively low pressures Only accessible through airlocks Employees exposed during the whole working shift Seite 8
Cut-and-cover method Seite 9
Agenda Introduction Health hazards Preventative occupational medicine Practical experience Seite 10
Health hazards Seite 11
Health hazards Gases under high pressure can have effects that they do not show under normal atmospheric pressure Inert gases: Nitrogen narcosis (rapture of the deep): from approx. 40m High pressure nervous syndrome (HPNS) increased excitability of the brain due to helium Gas bubbles in the blood and tissue Decompression sickness: gas embolisms, skin bends, aseptic bone necrosis (caisson sickness) Seite 12
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Health hazards Effects of irritants and toxic gases Nitrogen oxide -> Pulmonary oedema Carbon dioxide ->Hyperventilation, unconsciousness, cramps Carbon monoxide -> Headache, vertigo, palpitations, internal asphyxia Increased oxygen saturation-> Respiratory tract irritation, coughing, paresthesia, vertigo Seite 14
Agenda Introduction Health hazards Preventative occupational medicine Practical experience Seite 15
Legal basis Decree on the prevention of accidents and occupational diseases (VUV) Article 70: 70: For the prevention of occupational diseases that are specific to certain company categories or types of work For the prevention of certain risks relating to the employee personally Suva can impose an injunction subjecting a company, a part of a company or an employee to the regulations governing occupational healthcare. Seite 16
Preventative occupational medicine Professional divers as well as employees working under pressure are examined within the framework of preventative occupational medicine Scope and interval of the examinations are laid down by Suva Occupational Medicine Are largely based on the guidelines of the European Diving Technology Committee (EDTC) Seite 17
Preventative occupational medicine Scope of the examinations: Interval: Basic examination Interim examination Under the age of 45: Over the age of 45 : basic examination every 5 years interim examination once a year basic examination every 2 years interim examination once a year Cost of the examinations and loss of earnings paid by Suva Seite 18
Preventative occupational medicine Basic examination: Specific and extensive medical history Clinical examination (neurological, otorhinolaryngological, cardio-circulatory) Laboratory examination (blood count, hepatic enzymes, creatinine, blood glucose, urine analysis) Lung function test Electrocardiogram and Stresstest with stress - electrocardiogram Interim examination: Interview Seite 19
Preventative occupational medicine There must be an emergency plan A doctor with diving and high-pressure medicine qualifications must be available Most important therapeutic immediate measures: Monitoring and maintaining vital functions Provision of oxygen at normal pressure via a mask Pressure chamber, depending on the situation on-site Seite 20
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Agenda Introduction Health hazards Preventative occupational medicine Practical experience Seite 22
Practical experience The procedure used has proved itself in preventative occupational medicine examinations 88 companies with 420 employees Suitability: usually healthy, proven employees Reasons for unsuitability: cardio-vascular diseases, asthma, anxiety No major incidents Seite 23
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