Central venous catheterisation - 4
Preventing complications when inserting the catheter
Keeping the following points in mind can help prevent problems or complications with a CVC.
Experience of the operator with inserting CVC's
As with most procedures, the level of experience of the physician will reduce the chance of complications occurring.
If you have not been able to insert the catheter after three attempts seek help rather than continuing to get the catheter in. The incidence of complications after three or more attempts is six times the rate of one attempt.
An ultrasound probe can be used to identify the vein and measure its depth under the skin to help reduce the number of repeated attempts and/or complications developing. Subclavian insertion using an ultrasound guided technique is more difficult due to the position of the clavicle.
In a patient with a normal blood pressure and normal arterial oxygen tension, arterial puncture should be easily identifiable due to pulsatile flow into the syringe and bright red colour of the blood. But in hypotensive and hypoxaemic patients this can be difficult to assess.
If in doubt of venous or arterial cannulation, connect the catheter to a transducer and check the waveforms and pressure readings. Venous waveforms and pressure will indicate venous cannulation.
Blood gas sampling at the same time will assist confirmation, particularly if another sample is obtained simultaneously from another artery.
Catheter hubs should be closed to air at all times to prevent air being drawn into the vein causing an air embolism, due to the negative intrathoracic pressure generated with inspiration.
The position of the patient can also help prevent this complication by placing the patient in the Trendelenburg's position for insertion.
If air embolus occurs, the patient should be left in this position, with a left lateral decubitus tilt to prevent air entering the right ventricular outflow tract. 100% oxygen should be administered to help speed up the resorption of the air. If the cannula has reached the heart, attempt to aspirate the air.
Most studies of the use of prophylactic antibiotics have shown them to be beneficial in reducing the rate of catheter related blood stream infections.
However, this practice can encourage the emergence of antibiotic resistant organisms, so abide by local guidelines.