1. MONITORING OF CENTRAL VENOUS PRESSURE Dr. Subrata Kumar D.Card Student University Cardiac Center BSMMU, Dhaka.

2. What is CVP ? The central venous pressure (CVP) is the pressure measured in the central veins close to the heart. It indicates mean right atrial pressure and is frequently used as an estimate of right ventricular preload. CVP reflects the amount of blood returning to the heart and the ability of the heart to pump the blood into the arterial system. It is the pressure measured at the junction of the superior vena cava and the right atrium. 3. It reflects the driving force for filling of the right atrium & ventricle. It indicates the relationship of blood volume to the capacity of the venous system. Normal CVP in an awake , spontaneously breathing patient : 1-7 mmHg or 5-10 cm H2O. Mechanical ventilation : 3-5 cm H2O higher. 4. CENTRAL VENOUS PRESSURE MONITORING In central venous pressure monitoring, the physician inserts a catheter through a vein and advances it until its tip lies in or near the right atrium. Because no major valves lie at the junction of the vena cava and right atrium, pressure at end diastole reflects back to the catheter. 5. CENTRAL VENOUS PRESSURE MONITORING Contd.. When connected to a manometer, the catheter measures central venous pressure (CVP), an index of right ventricular function. CVP monitoring helps to assess cardiac function, to evaluate venous return to the heart, and to indirectly gauge how well the heart is pumping. 6. Methods to measure CVP 1. Indirect assessment: Inspection of jugular venous pulsations in the neck. 2. Direct assessment: Fluid filled manometer connected to central venous catheter. Calibrated transducer. 7. Methods to measure CVP contd... 1. Inspection of jugular venous pulsations in the neck. No valve between Right atrium & Internal Jugular Vein. Degree of distention & venous wave form reflects information about cardiac function. 8. The central venous (CV) line also provides access to a large vessel for rapid, high-volume fluid administration and allows frequent blood withdrawal for laboratory samples. CVP monitoring can be done intermittently or continuously. The catheter is inserted percutaneously or using a cutdown method. Typically, a single lumen CVP line is used for intermittent pressure readings. 9. To measure the patients volume status, a disposable plastic water manometer is attached between the I.V. line and the central catheter with a three or four-way stopcock. CVP is recorded in centimeters of water (cm H2O) or millimeters of mercury (mm Hg) read from manometer markings. Normal CVP ranges from 5 to 10 cm H2O or 2 to 6 mm Hg. 10. Any condition that alters venous return, circulating blood volume, or cardiac performance may affect CVP. If circulating volume increases (such as with enhanced venous return to the heart), CVP rises. If circulating volume decreases (such as with reduced venous return), CVP drops. 11. Relationship between water manometer and calibrated transducer : In terms of pressure 1cm H2O = 0.73 mmHg. 1 mmHg = 1.36 cm H2O. 12. Methods to measure CVP contd... 2. Fluid filled manometer connected to central venous catheter : CVP is measured using a column of water in a marked manometer. CVP is the height of the column in cms of H2O when the column is at the level of right atrium. Advantage: Simplicity to measure. Disadvantage: 1) Inability to analyze the CVP waveform. 2) Relatively slow response of the water column to changes in intrathoracic pressure. 13. Measurement of CVP cont 3. Calibrated transducer Automated, electronic pressure monitor. Pressure wave form displayed on an oscilloscope or paper. Advantages More accurate. Direct observation of waveform. 14. INDICATIONS FOR CENTRAL VENOUS CANNULATION 1. Central venous pressure monitoring 2. Pulmonary artery catheterization & monitoring 3. Transvenous cardiac pacing 4. Temporary hemodialysis 5. Drug administartion Concentrated Vasoactive drugs Hyperalimentation Chemotherapy Agents irritating to peripheral veins Prolong antibiotic therapy 15. INDICATIONS CONTD 6. Rapid infusion of fluids Trauma Major surgery 7. Aspiration of air emboli 8. Inadequate peripheral intravenous access 9. Sampling site for repeated blood testing 16. Measurement of CVP 17. Pressure transducer 18. CVP measurement & intrathoracic pressure CVP measurement is influenced by changes in intrathoracic pressure. It fluctuates with respiration. Decreases in spontaneous inspiration. Increases in positive pressure ventilation. CVP should be taken at the end expiration. PEEP applied to the airway at the end of exhalation , may be partially transmitted to the intrathoracic structures measured CVP will be higher. 19. Techniques of central venous cannulation: 1. Catheter over the needle Longer version of a conventional intravenous cannula. Catheter is larger than needle reduces the leakage of blood from the insertion site. Accidental arterial puncture can occur due to larger needle. Over insertion can damage the vein. 20. TECHNIQUES CONTD 2. Catheter over guidewire ( Seldinger technique) Preferred method of insertion. 18-20 G, small diameter needle is used. A guide wire passed down the needle in to the vein and needle removed. Guidewire commonly has flexible J shaped tip 1. Reduces the risk of vessel perforation. 2. Helps negotiate valves in vein. Once the wire is placed in the vein catheter is passed over it. 21. 3. Catheter through the needle or through cannula Catheter passed through a cannula or needle placed in the vein. Hole made in the vein by the needle larger than the catheter some degree of blood leakage around the site. Withdrawal of catheter through needle risks shearing off catheter Catheter embolisation 22. Routes of access of central vein COMMONLY USED VEINS : 1. Subclavian vein 2. Internal jugular vein 3. Femoral vein 4. Basilic vein (Antecubital fossa ) 23. ROUTES OF ACCESS CONTD LESS COMMONLY USED VEINS- 1. Axillary ( Anterior & lateral approach ) 2. External jugular 3. Brachial ( Mid- upper arm approach ) 4. Cephalic ( Ante- cubital fossa approach ) 5. Brachio cephalic ( Supra clavicular approach ) 24. ROUTES OF ACCESS 25. ASSESSMENT of the patient 1. Information Regarding procedures, alternative procedures, advantages & disadvantages, risk involved, care of the device & removal of device. 2. Informed consent 3. Allergies 4. Physical examination General physique, height, weight, physical features- bull neck, breasts, goitre, stoma, open wounds. 26. 5. Vascular assessment Anatomy of peripheral & central veins & their variants. H/o previous CVP catheterisation. Any evidence of venous thrombosis caused by presence of Central Venous Access Device. Thorax, abdomen, upper & lower limbs, neck presence of dilated collaterals, swelling, any sign of thrombosis or stenosis of veins. 27. 6. Respiratory function assessment Chest X- ray: To rule out emphysema/ COPD CT chest: Large effusion/ collapse. 7. CVS assessment Implanted pacemakers & defibrillators: Rule out catheters interfering with the position of leads of these devices & infection of such devices. 28. 8. Neurological assessment Level of conciousness. Effects of sedatives & analgesic drugs. Paralysed limb- inc risk of unrecognised extravasation of drugs. 9. Fractures & arthritis Fracture clavicle- CVAD should be placed on opp. side or jugular approach should be used. Fracture of UL bones- C/I for PICC. 10. Laboratory assessment Serum Electrolytes within normal range. Serum K+ - Risk of arrhythmias. 29. 11.Coagulation assessment APTT : 22 - 34 sec PT : 10.5 - 13.5 sec Platelet : 150 - 400 109 /L Warfarin : Either stopped or converted to heparin 3 days beforehand. INR : 1.5 or below should be achieved IV Unfractionated heparin : Stopped 3 hrs before insertion & restarted when haemostasis is achieved. LMWH : 12-24 hrs. 30. Complications Haemorrage Pneumothorax Air embolism Arteriovenous fistula Adjacent organ puncture Thrombosis Thrombo-embolism Skin infection & necrosis Sepsis 31. Documentation Document all dressing, tubing, and solution changes. Document the patients tolerance of the procedure. The date and time of catheter removal, and the type of dressing applied. Note the condition of the catheter insertion site and whether a culture specimen was collected. Note any complications and actions taken. 32. THANK YOU ALL