CENTRAL LINES AND ARTERIAL LINES Adult ll Clinical Course

LEARNING OUTCOMES THE STUDENT SHOULD BE ABLE TO:- Identify a central line and arterial line . Discuss the indication for central line and arterial line. Know how to measure CVP . Discuss the complications associated with central lines and arterial lines . Articulate the management of a patient with a central line and arterial line .

WHAT IS A CENTRAL LINE It is a catheter that provides venous access via the superior vena cava or right atrium

COMMON CENTRAL LINE INSERTION SITES Right internal jugular left internal jugular right subclavian left subclavian femoral (as a last resort) Or peripherally inserted central catheters (PICC) which are inserted via the antecubital veins (basilic vein is the best) in the arm and is advanced into the central veins Why would the femoral vein be used as a last resort?

TYPES OF CENTRAL LINE Single lumen Tripple lumen.

CENTRAL LINES Indications for CVP lines are:- Rapid administration of fluids and blood products in patients with any form of shock Parenteral feeding electrolytes or hypertonic solutions. measurement of central venous pressure Lack of accessible peripheral veins administration of irritant drugs

Procedure Position the patient as needed using pillows or rolled towels, or place the patient in the Trendelenberg position; this prevents air from being passively drawn into the venous system during the negative intrathoracic pressure generated by inspiration

Potential complications Haemorrhagefrom the catheter site -if it becomes disconnected from the infusion. Patients who have coagulation problems such as those on warfarinor those will clotting disorders are at risk. Catheterocclusion, by a blood clot or kinked tube -regular flushing of the CVC line and a well secured dressing should help to avoid this.

Potential complications Infection-redness, pain, swelling around the catheter insertion site may all indicate infection. Careful asepsis is needed when touching a CVC site. Swabs for MC&S should be taken if infection is suspected. Air embolus-if the infusion or monitoring lines become disconnected there is a risk that air can enter the venous system. All lines and connections should be checked at the start of every shift to minimisethe risk of this occurring.

Potential complications Catheter displacement-if the CVC moves into the chambers of the heart then cardiac arrhythmias may be noted, and should be reported. If the CVC is no longer in the correct position, CVP readings and medication administration will be affected.

CENTRAL VENOUS PRESSURE

What is CVP Central venous pressure (CVP) (also known as: right atrial pressure; RAP) describes the pressure of blood in the thoracic vena cava, near the right atrium of the heart. CVP reflects the amount of blood returning to the heart and the ability of the heart to pump the blood into the arterial system.

CVP Readings are used :- To serve as a guide to fluid balance in critically ill patients . To estimate the circulating blood volume. To assist in monitoring circulatory failure The normal range for CVP is 5-10cm H2O (2-6mmHg) when taken from the mid-axillary line at the fourth intercostalspace.

Central Venous Pressure Monitoring This is a helpful tool in the assessment of cardiac function , circulating blood volume , vascular tone and the patient’s response to treatment. However , CVP should not be interrupted Solely but in conjunction with other systemic measurements , as isolated CVP measurements can be misleading . CVP measurement should be viewed in conjunction with other observations such as pulse, blood pressure and respiratory rate and the patients response to treatment.

Methods of Central Venous Pressure Monitoring There are two methods of CVP monitoring manometer system: enables intermittent readings and is less accurate than the transducer system transducer system:enables continuous readings which are displayed on a monitor.

How to measure CVP ? Using a manometer 1. Explain the procedure to the patient to gain informed consent. 2. If IV fluid is not running, ensure that the CVC is patent by flushing the catheter.

supine position if possible. Alternatively, measurements can 3. Place the patient flat in a supine position if possible. Alternatively, measurements can be taken with the patient in a semi-recumbent position. The position should remain the same for each measurement taken to ensure an accurate comparable result.

Line up the manometer arm with the phlebostatic axis ensuring that the bubble is between the two lines of the spirit level.

Move the manometer scale up and down to allow the bubble to be aligned with zero on the scale. This is referred to as 'zeroing the manometer'.

Turn the three-way tap off to the patient and open to the manometer.

Open the IV fluid bag and slowly fill the manometer to a level higher than the expected CVP

Monitoring with transducers Transducers enable the pressure readings from invasive monitoring to be displayed on a monitor. To maintain patency of the cannula a bag of normal saline or heparinised saline should be connected to the transducer tubing and kept under continuous pressure of 300mmHg thus facilitating a continuous flush of 3mls/hr

Procedure for CVP measurement using a transducer EXPLAIN THE PROCEDURE TO THE PATIENT ENSURE THE LINE IS PATENT POSITION THE PATIENT SUPINE (IF POSSIBLE) AND ALIGN THE TRANSDUCER WITH THE MID AXILLA (LEVEL WITH THE RIGHT ATRIUM) ZERO THE MONITOR OBSERVE THE CVP TRACE DOCUMENT THE READING AND REPORT ANY CHANGES OR ABNORMALITIES ALWAYS EXPLAIN ANY PROCEDURE TO THE PATIENT HOW DO WE DO THIS? WHY DO WE LIE THE PATIENT SUPINE? OFF TO PATIENT OPEN TO AIR AND PRESS ZERO ON THE MONITOR. THIS REMOVES EXTRANEOUS PRESSURE TO ENSURE A CORRECT TRACE

Priming the system The transducer set must becarefully primed using a 500ml bag of 0.9% sodium chloride. Priming purges the air from the tubing system. After priming, all stopcocks/taps should be closed to air and all connections checked and tightened (McGhee and Bridges 2002).

Once the system has been primed, the pressure primed, the pressure bag should be inflated to 300mmHg for adult patients. This provides a constant flush through the device of approximately 3ml per hour and also provides the pressure needed to manually activate the in-line flush device

Levelling The transducer must be level with the patient’s right atrium. With the patient in the supine position, the position of the patient’s right atrium is estimated using external landmarks on the patient’s thorax.

Zeroing This is a bedside quality control test to ensure that the equipment is calibrated correctly. To zero the transducer, the three-way stopcock positioned immediately above the transducer should be switched off to the patient and opened to the atmosphere. The stopcock is an interface where the fluid meets the atmospheric air pressure. Providing the monitor recognises atmospheric air pressure as zero

Turn the tap off to the patient and open to the air by removing the cap from the three-way port opening the system to the atmosphere.

Press the zero button on the monitor and wait while calibration occurs.

When 'zeroed' is displayed on the monitor, replace the cap on the three-way tap and turn the tap on to the patient.

Observe the CVP trace on the monitor Observe the CVP trace on the monitor. The waveform undulates as the right atrium contracts and relaxes, emptying and filling with blood. (light blue in this image)

THE CVP WAVEFORM The CVP waveform reflects changes in right atrial pressure during the cardiac cycle A wave: right atrial contraction (P wave on the ECG)If the A wave is elevated the patient may have right ventricular failure or tricuspid stenosis. C wave: tricuspid valve closure (follows QRS complex on the ECG). V wave: pressure generated to the right atrium during ventricular contraction, despite the tricuspid valve being closed (latter part of the T wave on the ECG)

a – the rise in right atrial pressure caused by atrial systole. c – the ventricular contraction causes the tricuspid valve to bulge upwards into the right atrium (RA). x – the decrease in pressure in the RA as the tricuspid valve moves away from the RA during ejection of blood from the right ventricle. v – the peak in atrial pressure during ventricular systole when the tricuspidvalve is closed. y – the tricuspid valve opens and blood rapidly empties into the rightventricle during diastole.

NORMAL CVP MEASUREMENTS

CENTRAL VENOUS PRESSURE CVP CARDIAC COMPETENCE (REDUCED VENTRICULAR FUNCTION RAISES CVP) BLOOD VOLUME (INCREASED VENOUS RETURN RAISES CVP CENTRAL VENOUS PRESSURE CVP INTRATHORACIC AND INTRAPERITONEAL PRESSURE (RAISES CVP) SYSTEMIC VASCULAR RESISTENCE (INCREASED TONE RAISES CVP)

MANAGEMENT OF A PATIENT WITH A CVP LINE Monitor the patient for signs of complications Label CVP lines with drugs/fluids etc. being infused in order to minimise the risk of accidental bolus injection If not in use, flush the cannula regularly to help prevent thrombosis. A 500ml bag of 0.9% normal saline should be maintained at a pressure of 300mmHg.

Observe the insertion site frequently for signs of infection. Ensure all connections are secure to prevent exsanguination, introduction of infection and air emboli Observe the insertion site frequently for signs of infection. The length of the indwelling catheter should be recorded and regularly monitored. CVP lines should be removed when clinically indicated Transparent dressings should be used to permit continuous monitoring of the site. If infection of the CVP line is suspected blood cultures should be taken following removal of the line. The catheter tip should be sent for M C & S.

REMOVAL OF CENTRAL LINE The central venous catheter should be removed as soon as it is no longer needed or if the site appears infected. In any case, it should not remain in place for longer than five days. A physician’s order is required for removal

THIS IS AN ASEPTIC PROCEDURE THE PATIENT SHOULD BE SUPINE WITH HEAD TILTED DOWN ENSURE NO DRUGS ARE ATTACHED AND RUNNING VIA CUT THE STITCHES SLOWLY REMOVE THE CATHETER IF THERE IS RESISTENCE THEN CALL FOR ASSISTANCE APPLY DIGITAL PRESSURE WITH GAUZE UNTIL BLEEDING STOPS

ARTERIAL LINES

WHAT IS AN ARTERIAL LINE? AN ARTERIAL LINE IS A CANNULA USUALLY POSITIONED IN A PERIPHERAL ARTERY SUCH AS Radial artery brachial artery dorsalis pedis artery femoral artery

INDICATIONS FOR USING ARTERIAL LINE Ease of access Continuous monitoring of arterial blood pressure if patient is on intropic drugs if patient is on vasoactive drug if patient requires frequent arterial blood sampling Thereby avoiding the discomfort of frequent punctures of the artery eg tests for blood gases, serial blood lactate levels, full blood count, u&e’s etc.

COMPLICATIONS ASSOCIATED WITH ARTERIAL LINES HYPOVOLAEMIA ACCIDENTAL INTR-ARTERIAL INJECTION OF DRUGS LOCAL DAMAGE TO ARTERY HYPOVOLAEMIA – ACCIDENTAL DISCONNECTION OF TUBING FROM THE CANNULA CAN RESULT IN SEVERE HAEMORRHAGE AND HYPOVOLAEMIA NO DRUGS SHOULD BE ADMINISTERED THROUGH THE ARTERIAL LINE AS IT CAN CAUSE DISTAL ISCHAEMIA AND NECROSIS WITH SOMETIMES PERMANENT DAMAGE LOCAL DAMAGE TO ARTERY – THIS IS THE MOST COMMON COMPLICATION. IT IS IMPORTANT TO KEEP AN EYE ON THE DISTAL END EG FINGERS WATCH FOR SIGNS OF CHANGE IN TEMPERATURE, MOTTLING OR BLANCHING PARTICULARLY WHEN THE LINE IS FLUSHED.

THE ARTERIAL WAVEFORM The arterial waveform reflects the pressure generated in the arteries following ventricular contraction and can be described as having:- Anacrotic notch Peak systolic pressure Dicrotic notch Diastolic pressure

REMOVAL OF ARTERIAL LINE THIS IS AN ASEPTIC PROCEDURE REMEMBER UNIVERSAL PRECAUTIONS THE PROCEDURE SHOULD BE EXPLAINED TO THE PATIENT TAKE DRESSING OFF LINE REMOVE ARTERIAL LINE ENSURING THAT THE ENTRY SITE IS COVERED WITH GAUZE APPLY DIGITAL PRESSURE FOR AT LEAST 5 MINUTES TO ENSURE HAEMOSTASIS DRESS SITE WITH GAUZE AND MICROPORE ASSESS THE PERIPHERAL CIRCULATION AS THROMBOSIS CAN OCCUR AFTER REMOVAL

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