MAGNETIC RESONANCE IMAGING – Purpose, Indications and Client Preparation

Magnetic resonance imaging (MRI) is one of the most expensive noninvasive diagnostic options; a verity of data may be obtained in a single image. It provides the best information on chamber, size, wall motion, valvular function and great vessel blood flow without the use of ionizing radiation

PURPOSE

• MRI is commonly used for examination of the aorta and detection of tumors, aneurysms, masses, cardiomyopathies and pericardial disease
• MRI can show the heart beating and the blood flowing in any direction
• All standard quantitative functional indices, except transstenotic gradients can be obtained from an MRI study

INDICATIONS

• Normal morphology and structural changes
• Wall thickness, chamber volumes, valve areas, vessel cross-section and extent, location and size of lesions
• Global and regional biventricular function, including ejection fraction, stroke volume and cardiac output
• Blood flow quantifications within vessels over the cardiac cycle
• Tissue characterization of paracardiac and intracardiac masses, pericardiac masses, pericardial diffusion and myocardial infarction

CLIENT PREPARATION

• Inform the client that the test is noninvasive
• Provide written information about the test, if available
• Explain to client that he will lying in  one position for a long period
• Screen the client for claustrophobia and anxiety; these can be reduced by premeditation with an antianxiety drug

MAGNETIC RESONANCE IMAGING – Definition, Purpose, Principle, Instruction, Preparation of the Client, MRI Equipment, Procedure, After Care, Advantages of MRI, Disadvantages and Contraindications

Magnetic resonance imaging is also called as nuclear magnetic resonance; this technique was independently discovered by Felix Bloch and Purcell in 1952. He explained that when the nuclear energy is exposed to a magnetic field, it behaves like a magnet. This nuclear magnetism with its magnetic field helps the nuclear energy to act as a small magnet

DEFINITION

• Magnetic resonance imaging (MRI) is a noninvasive diagnostic test with a powerful magnetic field to obtain images of different areas of the body
• Magnetic resonance imaging or MRI uses a powerful magnetic field and radiofrequency waves to produce computerized images of internal organs and tissues

PURPOSE

• To produce tissue analysis and images not readily seen on standard X-ray
• To detect tiny lesions of multiple sclerosis on brain and spinal cord
• To detect slipped disc in the spinal cord
• To get a clear image of internal structures in response to the magnetic field, created by harmless, low energy radiowaves
• To detect, localize and stage malignancies of the CNS, spine, head and neck and musculoskeletal system

PRINCIPLE

• MRI does not employ ionizing radiations, so it is free from radiations where as CT scan is by X-ray
• The picture from an MRI are opposite of the CT scan. In MRI the bones appear black whereas in CT scan bones appear white
• MRI is used to study the tissue metabolism by spectroscopy where as CT not
• MRI is used to obtain sectional views in any plane unlike CT scan which is more or less restricted to cross-sectional imaging
• MRI detects water because it focuses on the behavior of hydrogen atom in water molecule. This allows MRI to distinguish between water proof and water rich tissues
• MRI gives early warning of myocardial infarction or stroke with the help of sodium or phosphorus ions

INSTRUCTIONS

• The client informed that it is painless noninvasive procedure and he will hear a lot of noises during the procedure
• All jewelry, eye glasses and hair pins/clips or any other metal objects should be removed
• Carefully question and screen for the presence of any metal implantation
• Consent for contrast and general anesthesia to be taken
• Patient should wear only cotton dress
• No dietary restriction for MRI even for contrast, unless anesthesia is planned
• Extra blanket may be provided as the client is in the air conditioned for more than 45 minutes

PREPARATION OF THE CLIENT

• Explain the procedure to the patient in a simple language
• Remove all metal objects, clips and jewelry from the patient’s body
• Give information about actual procedure, staff involved, duration and sensation to be experienced and probable outcome
• The patient is assured the investigation is safe and painless
• Psychological support and assistance to be given for claustrophobia

MRI EQUIPMENT

• Magnet
• Radiofrequency (RF) coils (transmitter/receiver)
• Gradient coils
• Computer
• Display unit
• Digital storage facilities

PROCEDURE

• After removing all metal objects, the client lies on a padded stretcher that slides into tunnel like chamber
• Place the head in a plastic helmet like structure
• Place the arms at the side of the X-ray table is the rolled several feet into the scanner
• The patient is placed in a strong magnetic field up to 40,000 times stronger than the earth’s magnetic field and is then subjected to precise, computer programmed bursts of radiofrequency waves
• The client feels nothing and hears only loud noises caused by the pulsating radiofrequency waves the resemble a Jackhammer or drill which lasts about a few minutes

AFTER CARE

• Ask the patient to get up slowly, it the client may feel dizzy provide bed rest
• Check the vital signs and record it
• Assess the allergic reactions if dye administered
• For clients who had MRI under general anesthesia kept fasting for 3-4 hours and IV fluids to be given

ADVANTAGES OF MRI

• Does not expose the client to radiation because it is non-ionizing radiation
• Results are obtained rapidly
• Multisectional imaging
• It is safe even contrast dye is used
• Cost affordable when comparing with other invasive surgical procedures
• Provides tissue characterization and blood flow
• Provides clear images of moving organs
• Helps to detect disorders that cause loss of myelin from nerve such as multiple sclerosis

DISADVANTAGES

• Long imaging time
• Many protocol options
• Correct choice of machine parameters essential
• Poor bone and calcium detail
• Not available in all areas
• Difficult to manage and monitor patients who are critically ill

CONTRAINDICATIONS

• Clients with pacemaker are contraindicated
• Cannot use in clients who are extremely obese
• Cannot use in clients with metal implants

MAGNETIC RESONANCE IMAGING – Indications, Advantages, Nursing Consideration, Contraindications, Interfering Factors, Client Preparation, Procedure and Post-Procedural Care

Magnetic resonance imaging (MRI) is a noninvasive test that employs a powerful magnet, radio waves and a computer to help diagnose respiratory disorders by providing high-resolution, cross sectional images of lung structures and by tracing blood flow. MRI’s great advantage is its ability to see through bone and to delineate fluid-filled soft tissue in great details, without using ionizing radiation or contrast media

INDICATIONS

• It provides valuable information about body’s biochemistry by placing the client in a magnetic field
• MRI is based on how hydrogen atoms behave when they are placed in a magnetic field and then distributed by radio frequency signals

ADVANTAGES

• MRI provides better contrast between normal tissues and pathogenic tissues
• It provides a natural contrast from other tissues to the blood vessels when using MRI
• It is possible to image the transverse, sagittal and coronal planes directly with MRI

NURSING CONSIDERATION

• Instruct the client to remove all jewelry and taken everything out of his packet
• Emphasize that there must be no metal may demagnetize the magnetic strip on a credit card to stop a watch from ticking
• Make sure the client has notified his doctor if he has any metal inside his body, such as a pacemaker, orthopedic pins or discs and bullets or sharper fragments
• Inform the client he will asked to lie on a table slides into an 8’ (2.4 m) tunnel inside the magnet
• Advise him to breathe normally but not to talk or move during the test to avoid distorting the results
• Inform him the test usually takes 15-30 minutes
• Warn the client that the machinery will be noisy with sounds ranging from an incessant ping to a loud bang
• The client may feel claustrophobic or board. Encourage him to relax and to concentrate on breathing or a favorite subject or image

CONTRAINDICATIONS

• Clients who are extremely obese
• Clients who are pregnant, because the long-term effects of MRI are not known at this time
• Clients who are confused and agitated
• Clients who are claustrophobic if using an enclosed scanner
• Clients who are unstable and require continuous life support equipment, because monitoring equipment cannot be used inside the scanner room
• Clients with implantable metal objects such as pacemaker, infusion pumps, aneurysm clips, inner ear impacts and metal fragments in one or both eyes, because the magnet may move the object within the body and injure the client

INTERFERING FACTORS

Movement during the scan causes artifacts on MRI

CLIENT PREPARATION

• Explain the procedure to the patient
• Inform the client that there is no exposure to radiation
• Obtain informed consent if required by the institution
• Inform the client that he or she can drive without assistance after the procedure
• Tell parents of young client’s that they may read or talk to a child in the scanning room during procedure, because no risk of radiation from the procedure exists
• If possible, show the client a picture of the scanning machine and encourage verbalization of anxieties. Some client’s may experience claustrophobia. Antianxiety medications may be helpful for those with mild claustrophobia
• Instruct the client to remove all metal objects (e.g., dental brides, jewelry, hair clips, belts, credit cards) because they will create artifacts on the screen. The magnetic field can damage watches and credit cards
• Inform the client that he or she will be required to remain motionless during this study. Any movement can cause artifacts on the screen
• Inform the client that during the procedure he or she may hear a thumping sound; earplugs are available if the client wishes to use them
• Inform the client that no fluid or food restrictions are necessary before MRI
• For comfort, instruct the client to empty the bladder before the rest

PROCEDURE

• The client lies on the flat form that slides into a tube containing the doughnut shaped magnet
• The client is instructed to lie very still during the procedure
• During the scan, the client can talk to and hear the staff via microphone or earphones placed in the scanner
• A contrast medium called gadolinium (magnevist) has been approved by the US Food and Drug Administration. This is a paramagnetic enhancement agent that crosses the blood-brain barrier. It is especially useful for distinguishing edema from tumors
• This procedure is performed by qualified radiological technologist in approximately 30 to 90 minutes
• Inform the client that the only discomfort associated with this procedure may be lying still on a surface and possible tingling sensation in teeth containing metal filling. Also, an injection may be needed for administration of magnevist

POST-PROCEDURAL CARE

Inform the client that no special post-procedural care is needed

HOLTER MONITORING – Normal Findings, Definition, Purpose, Findings, Client Preparation, Components, Procedure and After Care

Holter monitoring permits the recording of cardiac electric activity over time (usually 24 hours) on a cassette tape recorder. It allows the client to perform normal daily activities can be determined. When the client wears a portable holter monitor, an ECG tracing may be recorded continuously over a period of a day or longer on an out-patient basis

Holter monitoring (ambulatory electrocardiography) evaluates the client’s heart rate and rhythm during normal daily activities, rest, and sleep over 24 hours (occasionally 48 hours). The holder monitor consists of a continuous electrocardiogram recording on a cassette tape that is boxed inside. After 24 hours, the monitor with the tape is returned to the cardiac center and is scanned or reviewed for abnormal findings such as cardiac dysrhythmia

NORMAL FINDINGS

No abnormal electrocardiography findings

DEFINITION

Holter is monitoring or 24 hours ambulatory monitoring provides a record of client’s heart rate and rhythm over a period of 24-48 hours while the client is engaged in the activities of daily living

PURPOSE

• To identify and record cardiac arrhythmias associated with normal daily activities, which cannot be detected by routine ECG
• To correlate these arrhythmias with symptoms such as syncope, palpitation, chest pain. Light headedness or dyspnea as described by the client
• To assess the effectiveness of antiarrhythmic or anginal drugs
• To evaluate the functioning of the artificial pacemaker suspected of malfunctioning
• To detect ST segment alterations during exertion in clients with obscure chest pain

FINDINGS

• Conduction disturbances
• Dysrhythmia

CLIENT PREPARATION

• Inform client regarding the purpose of the holder monitoring and the vital role he or she plays in obtaining the needed information
• Check the holter monitor’s indicator light to determine if the battery is functioning
• The client is instructed to keep a daily of activities and is taught how to trigger the event marker
• Shave the site if the chest is hairy to apply electrodes to the chest
• Have the client demonstrate triggering the event marker. The client will push the marker whenever pain or other symptoms occur
• Give the client a writing pad to record activities during the test time

COMPONENTS

• Recording apparatus: this is like a small transistor radio that can be carried over the shoulder or connected to a waist belt. This will contain a blank tape on which the heart rhythm is recorded for 24 hours
• Client’s dairy: the client recordings all activities and any unusual symptoms experienced with time
• Holter monitor scanner: it is a computer system which can scan 24 hours tape in 12-15 minutes for any arrhythmia

PROCEDURE

• Explain the procedure to the client and prepare the chest for electrodes
• Apply the electrode jelly and fix the electrodes securely to the chest
• Fix the connecting wires from each lead to the client’s skin with a stress loop to prevent accidental dislodging of the leads
• Connect the lead system to the holder recorder which is prechecked and has a blank magnetic tape and fresh batteries
• The recorder is fastened to the client’s waist using a belt. When the recorder is activated, ECG signals are recorded on the magnetic tape
• Note the time in the client’s dairy when the recorder is activated
• Explain to the client to record all the activities with time in the dairy and also any unusual symptoms experienced
• Instruct client to come back with dairy and the equipment on the next day at the specified time
• Once the client reports back put off the monitor and remove it from the client with the electrodes
• Play back the tape on the scanner and identify the areas of abnormal wave patterns
• Record these areas on the ECG paper as a permanent print out which can be analyzed later

AFTER CARE

• Remove electrodes and cleanse the site of gel
• Observe the skin for signs of irritation

ELECTROCARDIOGRAM – Normal Conduction System of Heart, Purpose of ECG, Components of ECG, ECG Graph Sheet, Heart Rate, Rhythm, Blocks, Axis, Hypertrophy, Electrolyte Disturbance in ECG, Myocardial Infarction, 12 Lead ECG, Lead Placement, Indications of 12 Lead ECG, Cause of Abnormal ECG Pattern, Preparation of the Patient, Preprocedural Care, Procedure, After Care and Nurses Responsibility (NURSING PROCEDURE)

Electrocardiogram (ECG) is invented by Enthovan in 1901. It is a permanent record of the electrical activity of the heart. It is a tracing made of the various phases of the heart action by means of an electrocardiography. It is a graphical representation that describes about the heart

The electrocardiogram is an instrument which detects very small electrical signals, generated by depolarization and repolarization of the myocardium. Electrodes are attached to the limbs and chest of the patient, and electrical changes are amplified and recorded on a moving paper

NORMAL CONDUCTION SYSTEM OF THE HEART

The electrical impulse is generated in the sino-atrial node (pacemaker) of the heart. it spreads through the both atria and cause atrial contraction. It crosses the atrioventicular node and is passed down through right and left bundle branches and finally reaches the Purkinje fibers, where the ventricular contraction take place

PURPOSE OF ECG

• Electrocardiogram is the most important signal tool for the diagnosis of arrhythmias
• It is helpful to study the cardiac functions – rate, rhythm, and axis
• It helps to diagnose cardiac disease condition – myocardial infarction, injury, ischemia and hypertrophy
• It helps to detect electrolytes imbalance hyperkalemia
• To give valuable diagnostic information about cardiac function
• To confirm the coronary heart disease in most cases
• To demonstrate cardiac arrhythmias such as ventricular tachycardia and heart block

COMPONENTS OF ECG

Electrocardiography consists of waves, complexes and intervals

• Wave or complex: it is a deflection that can be positive or negative wave-atrial depolarization QRS complex-ventricular depolarization. T wave – ventricular repolarization
• Segment: A is the period of time between a wave or complex, e.g. ST-segment
• Interval: an interval is the time between two points on the ECG, e.g. PR- interval
• Time duration (normal) for the P-wave – 0.08 seconds PR-interval less than 0.20 seconds (average 0.16 seconds), QRS complex 0.08 seconds, ST segment – 0.12 seconds and T-wave – 0.16 seconds

ECG GRAPH SHEET

• ECG tracing are recorded on graph paper, which is divided into small (1/1 mm) squares light lines and large (5/5 mm) squares by heavier lines
• Horizontal lines (Y-axis) measures the amplitude (voltage), one small square represents 1 mm and a large square represents 5 mm or 0.5 mm
• The vertical lines (X-axis) measure time, each small square represents 0.20 seconds

HEART RATE

• Normal heart rate is 60 to 100 beats per minutes, less than 60 beats per minute called bradycardia and more than 100 beats per minutes called tachycardia
• The heart rate per minute is equal to the number of large squares between the R-waves divided into 300, e.g. if there are two large squares between the R-waves 300 divided by 2 = 150 beats per minutes
• Count the number of small squares between R-R intervals and divide. When the heart rhythm is irregular, count the QRS complexes in 6 seconds and multiply the number by 10 to get the patient’s heart rate per minutes (30 large block are equal to 6 second)

RHYTHM

• Atrial rhythm measures the distance between two consecutive P-waves (P-P interval). If the distance between all the P-waves are same, the atrial rhythm is regular
• Ventricular rhythm measures the distance between the two consecutive R-waves (R-R interval)
• Sinus tachycardia – heart rate is more than 100 beats per minutes with normal PQRST waves
• Sinus bradycardia – heart rate is less than 60 beats per minutes with normal PQRST waves
• Premature atrial contraction (PAC) RR-intervals vary with a compensatory pause after the PAC
• Paroxysmal atrial tachycardia (PAT) heart rate is 150 to 250 per minutes, P-wave are difficult to recognize. QRS complexes are normal in shape
• Atrial flutter – P-waves form saw tooth pattern, there are more than one P-wave between two consecutive   QRS complexes
• Atrial fibrillation – no regular P-wave, P-wave appearing as a wavy baseline
• Paroxysmal junctional tachycardia – heart rate is 150 to 220 beats per minutes, P-wave are either absent or appear inverted

BLOCKS

• Sino-atrial blocks (SA block) occasional long pauses between R-R complexes
• First degree AV block: P-R interval is prolonged beyond 0.20 second
• Second degree AV block (Mobitz type 1 or Wenckebach) P-R interval is progressively prolonged until finally as QRS complex is dropped. Second degree AV block (Mobitz type II) A QRS complex is present after every 2^nd, 3^rd, 4^th wave
• Third degree AV block (Complete heart block) P wave, do not have any relation with QRS complexes
• Right bundle branch block (RBBB): M-shaped QRS complexes in lead V1, V2, QRS complexes measure more than 0.12 second in width and are above the isoelectric line in lead Vi. Broad and slurred S-wave in lead VS and V6
• Left bundle branch block (LBBB): M-shaped QRS complexes in leads V5 and V6. QRS complexes prolonged more than 0.12 second and are below the isoelectric line in lead V1. Deep S-wave in leads V1 and V2
• Premature ventricular contractions (PVCs): No P-wave, QRS complexes are wide and bizarre with T-wave in opposite direction
• Ventricular tachycardia: No P-waves, QRS complexes are wide and bizarre and resemble PVC in succession
• Ventricular fibrillation: A wavy baseline, no discernable QRS complexes. Ventricular asystole – no wave pattern, usually only a flat line present

AXIS

• It refers to the direction of depolarization which spreads throughout the heart to stimulate the myocardium to contract
• Vector: it shows the direction in which most of the stimulus is traveling. QRS vector is always AV node. QRS vector-normally points downwards and to the patients left side
• We can locate the position of the QRS vector with in a large cycle around the heart. The center point is AV node. QRS vector changes in hypertrophy (vector is less than 90 degree angle)  and infarction (vector is more than 90 degree angle)
• Normal axis: QRS vector shows left downwards points in 0 to 90 degree angle. Lead 1 QRS vector right side called positive vector and left side called negative vector. Lead 1 positive called normal axis
• AVF lead shows lower half is positive and upper half is negative. The AVF positive vector is the normal axis
• Normal axis defined as lead 1 positive and AVF lead positive. Left axis deviation defines lead 1 positive and AVF lead negative
• Right axis deviation defines as lead 1 negative and AVF lead positive. Extreme right axis deviation defined as lead 1 negative and AVF negative

HYPERTROPHY

• Hypertrophy is defined as enlargement of the tissue or organ
• Atrial enlargement includes right atrial enlargement (RAE) and left atrial enlargement (LAE). Right atrial enlargement is peaked P-wave, more than 2.5 mm in any lead (best seen in II, III, V3 and V1). Left atrial enlargement is P-wave duration is more than 0.08 seconds, may have plateau or notched counter. Terminal and deep invasion of the P wave is V2 or V1
• Right ventricular hypertrophy shows dominant R in V1 or V2 essential
• Dominant S in I, AVL, V5 or V6 and inverted T and depressed ST in leads with dominant R
• Left ventricular hypertrophy shows large R wave in lead I, AVL, V5 and V6 and more than 30 mm. inverted T and depressed ST in leads with a large R-wave. Essential criteria for left ventricular hypertrophy is S in V1 or V2 + R in V5 or V6 = /35 MM

ELECTROLYTE DISTURBANCE IN ECG

• Normal serum potassium (K) value is 3.5 to 5.0 mEq/L. extremely serious problem occurs if potassium level less than 2.5 mEq/L or more than 7.0 mEq/L
• If the potassium level less than 5.0 mEq/L called hyperkalemia causes wide flat P wave, prolonged PR interval, decreased R-wave, widen QRS complex and peaked narrow T-wave in the ECG
• Serum potassium level less than 3.5 mEq/L is called hyperkalemia causes prolonged P wave, depressed ST segment and large U-wave is seen in ECG
• Serum calcium level is 8.5 – 10.5 mg/dL. If the serum calcium level less than 8.5 mg/dL is called hypocalcemia. Calcium level more than 10.5 mg/dL called hypercalcemia. Hypercalcemia shows increased QT interval and hypocalcemia shows decreased QT interval in the ECG

MYOCARDIAL INFARCTION

• Anterioseptal (anterior) myocardial infarction causes ECG changes are abnormal Q wave in lead 1, AVL and V1-V3. Reciprocal changes are depressed ST segment in lead II, III, and AVF
• Anteriolateral (lateral) myocardial infarction causes abnormal Q-wave in lead 1, AVL and V5-V6. Reciprocal changes are depressed ST in lead II, III and AVF
• Inferior myocardial infarction causes abnormal Q wave in lead II, III and AVF
• Posterior myocardial infarction causes often large dominant R in lead V1 and V2

12 LEAD ECG

Electrocardiogram Consist of Record from 12 Leads

The three standard bipolar leads (I, II and III), three unipolar limb leads (AVR, AVL, AVF) and six unipolar chest leads (V1-V6)

LEAD PLACEMENT

• Lead I: right arm to left arm
• Lead II: right arm to left leg
• Lead III: left arm to left leg
• AVR: right arm
• AVL: left arm
• AVF: left foot
• V1: 4^th RICS at right sterna border
• V2: 4^th LICS at left sternal border
• V3: midway between V2 and V4
• V4: 5^th LICS at midclavicular line
• V5: 5^th LICS at anterior axillary line
• V6: 5^th LICS at midaxillary line

INDICATIONS FOR 12 LEAD ECG

• Dysrhythmia
• Chest pain
• Myocardial infarction
• Heart rate determination
• Hypertrophy or chamber dilatation
• Preoperative assessment
• Pericarditis
• Effects of systemic disease on heart
• Effects of electrolyte disturbances

CAUSE OF ABNORMAL ECG PATTERN

• Skeletal muscle activity or movement of the patient
• Loose electrodes
• Damaged or broken wires
• Improper connections
• Improper placement of electrodes
• Electrical interferences

PREPARATION OF THE PATIENT

• There is no way special preparation for the investigation
• Explain the procedure to the patient and relatives that the seemingly complex apparatus will do no harm but will give information on the action of the heart
• There should not be any ornaments during ECG on the body or the leads should not come in contact with the ornaments
• Apply jelly to the skin where electrode is to be attached to have a good contact between the skin and the electrode
• Give flat and relaxed position to the patient because any movements or muscular twitching recorded by the machine may alter the tracings
• Clean the jelly off the electrode sites before leaving the patient

There are specific positions for the placement of the chest leads. The improper placement of the chest leads can distort the tracing and alter the diagnosis

PREPROCEDURAL CARE

• Check and arrange the ECG machine, cables, and electrodes and needed articles ready in advance
• Explain the procedure clearly to the patient and family
• Check the doctor’s order for the ECG
• Identify the patient name, age, Id. No. and diagnosis
• Inform the patient not to move during procedure

PROCEDURE

• Position the patient relaxed and flat
• Inform the bystanders to keep away, to prevent them touching the patient during procedure
• Enter the identification data of the patient
• Expose the needed area for connecting electrode
• Stay with the patient till it get over

AFTER CARE

• Clean the patient’s electrode site with gauze or tissue paper
• Ambulate and transfer the patient send the ECG record to doctor for interpretation
• Replace the ECG machine and articles to the proper place
• Record and report in the nurse’s sheet

NURSE’S RESPONSIBILITY

• Nurses working in coronary care unit and intensive care unit should know to operate the ECG machine
• Nurses should able to interpret and identify the dysrhythmia
• Nurses should understand about the dysfunctions and loose connections
• Nurses working in coronary care unit are responsible in ECG interpretation and treating with appropriate life-saving method as per institutional protocol

CENTRAL VENOUS PRESSURE – Objectives, Indications, Indication of Lowered CVP, Indication of Increased CVP, Site for Catheter Placement, General Instructions, Preliminary Assessment, Preparation of the Patient and Environment, Equipment, Procedure, Measurement Concept Validation Plan (MCVP) Measurement, Interpretation of CVP, False CVP, Post-Procedure Care and Complications (NURSING PROCEDURE)

Central venous pressure (CVP) is the pressure within the superior vena cava, reflecting the pressure under which the blood is returned to the superior vena cava and right atrium

Central venous pressure is determined by vascular tone, blood volume, and the ability of the right heart to receive and pump blood

Central venous pressure is one of the hemodynamic measurement techniques used to measure the pressure in the right atrium or within the vena cava

Central venous pressure is a dynamic or changing measurement. The change in CVP correlated with patient’s clinical status

OBJECTIVES

• To evaluate the adequacy of circulating blood volume and assess the degree of hypovolemia, e.g. in shock
• To provide access to central veins for fluid replacement in case of emergency
• To administer high caloric fluid diet intravenously in certain chronic hypercatabolic states, e.g. burns (intravenous hyperalimentation)
• To serve as a guide in fluid replacement in seriously ill patients
• To administer long-term chemotherapy

INDICATIONS

• Central venous pressure reflects right ventricular failure. Most right ventricular failure is secondary to left ventricular failure
• Central venous pressure is a more useful indication of adequacy of venous blood volume and alternations of cardiovascular function
• Cardiothoracic surgery
• Management of patient in shock in ICU
• Transplant surgery
• Normal CVP: 2-12 cm H₂O

INDICATION OF LOWERED CVP

• Early left ventricular failure
• Decreased circulating volume
• Vasodilation/peripheral pooling
• Septic shock

INDICATION OF INCREASED CVP

• Valvular stenosis
• Pulmonary hypertension
• Increased circulating volume
• Vasoconstriction
• Hypertension

SITE FOR CATHETER PLACEMENT

• Subclavian vein
• Internal or external jugular veins
• Median basilic vein

GENERAL INSTRUCTIONS

• Do not give head down tilt to a patient of impending cardiac failure
• Before introducing bigger catheter, incise skin with a No. 15 blade
• Catheter, from which free blood cannot be aspirated, should not be left in the skin
• CVP catheter should be taken to prevent blocking by continuous flush drip with low flow rates
• Dressing over puncture site should be changed on alternative days, with aseptic precautions
• Periodic blood samples should be taken for culture

PRELIMINARY ASSESSMENT

Check

• The doctor’s order for specific instructions
• Check the assembly of the catheter
• General condition and diagnosis of the patient
• Mental status to follow instructions
• Articles available in the unit

PREPARATION OF THE PATIENT AND ENVIRONMENT

• The procedure should be explained to the patient
• The CVP site should be prepared by shaving and cleansing with an antiseptic solution
• Measure the length of the manometer
• Ensure that the facilitates for cardiopulmonary resuscitation, intercostals drain and X-ray of the chest are available
• Measure the length of catheter required from anatomical puncture point to superior vena cava
• Assemble articles required for the procedure
• Place the patient in a comfortable position. This is the baseline position used for subsequent reading

EQUIPMENT

• Venous pressure apparatus with water manometer
• Cut down tray with intravenous catheter
• Infusion solution and infusion catheter
• Three way stop clock
• IV pole attached to bed arm board and adhesive tape
• Carpenter’s level (for establishing zero point)
• ECG monitors

PROCEDURE

• Attach the manometer to the IV pole with the zero point of the manometer on the level with the patient’s right
• Mark the midaxillary line on the patient which is the reference point for subsequent reading
• The intravenous catheter (about 24 inches long, size 14 or 16 gauge) is passed through the median basilica, subclavian or jugular vein
• CVP catheter is connected to a 3 way stopcock which communicates with the manometer and an open IV system
• Catheter is secured by a suture to prevent accidental removal and apply dressing

MEASUREMENT CONCEPT VALIDATION PLAN (MCVP) MEASUREMENT

• Always adjust the position of the patient to the position used for first reading
• Position the zero point on the manometer with the level of the atrium
• Turn the stopcock so that the IV solution flows into the manometer filling 20 to 25 cm level
• Turn the stopcock again so that the solution in the manometer flows into the patient
• Observe the fall of height of the column of fluid in the manometer. Record the level at which the stabilizes
• Turn the stopcock against to allow the IV solution to flow from the container to the patient’s vein by a slow drip

INTERPRETATION OF CVP

• Normal CVP value ranging from 2 cm to 14 cm of H₂O
• Low BP and low CVP hypovolemia
• High or normal BP and high CVP – over transfusion
• Low BP and high CVP – cardiac dysfunction

FALSE CVP

Before any measurement of CVP is taken as fine, chances of false high or low reading should be kept in mind and ruled out

Causes of False High CVP

• Leakage in the system
• Wrong zero reference point

POST-PROCEDURAL CARE

To prevent chances of infection when CVP catheter is kept for a long time in a critically ill patient, special care should be taken such as:

• Dressing over puncture site should be changed on alternate days, with aseptic precautions
• Changing of dressing in ward should be done with aseptic precautions
• Infusion set should be changed daily
• Periodic blood samples should be taken for culture

COMPLICATIONS

• Pneumothorax: commonly occurs with subclavian cannulation. It accounts for 30% of reported complications. Incidence can be reduced by correct placement.
• Air embolism: in hypovolemic tachypneic patient and crying babies, potential for rapid air entry should not be underestimated. To prevent this always expel the air from the tubing before connecting them into the vein. All connections should be secured to prevent accidental dislodging of the tube and entry of air into the veins
• Clot formation: the CVP line should always be connected to an IV infusion to prevent clot formation in the intravenous catheter
• Infection: use strict aseptic techniques when preparing the tubing and/or when changing the tubing. Inspect the catheter insertion site daily for pain, swelling or exudates
• Arrhythmias: maintain ECG monitoring to detect any arrhythmias caused by the passage of catheter into the right ventricle. A chest X-ray may be taken to check the position of the catheter in the right atrium
• Fluid overload: carefully monitor the CVP reading. Watch for other signs of fluid overload such as pulmonary edema, respiratory distress, frothy sputum, etc

CARDIAC CATHETERIZATION – Definition, Purpose, Equipment, Precatheterization Care, During Procedure and Post-catheterization Care (Nursing Procedure)

DEFINITION

Invasive diagnostic procedure in which one or more catheters are introduced into heart and selected blood vessels to measure pressures in various heart chambers and to determine oxygen saturation in the body

PURPOSE

• To determine appropriate treatment, e.g. PCA/CABG, if atherosclerosis is present
• To assess patency of coronary arteries
• To measure pressures in various chambers of heart
• To obtain blood samples for measurement of hemocrit and oxygen saturation
• To obtain clear picture of cardiac anatomy prior to heart surgery
• To confirm diagnosis of heart disease and determine extent to which disease has affected structure and function of heart
• To obtain clear picture of cardiac anatomy prior to heat surgery
• To allow infusion of fibrinolytic agent directly into occluded coronary artery to restore coronary blood flow
• To obtain endocardial biopsies

Right heart catheterization: passing radio-opaque catheter from antecubital or femoral vein into right atrium, right ventricle and pulmonary vasculature

Left heart catheterization: insertion of catheter into right brachial artery or femoral artery, ascending aorta and into left ventricle. It can also be performed transeptally from right atrium, left atrium, and into left ventricle

EQUIPMENT

Cardiac monitor, pressure monitoring device, fluoroscope, sterile radio-opaque cardiac catheters, radio-opaque dye, sterile liner for draping, cleaning solutions, sterile gloves, cardiac catheterization pack, cut down set scalpel blade and emergency equipment

PRECATHETERIZATION CARE

• Explain procedure, purpose and risks involved
• Get consent from patient and relative
• Explain that this procedure will be performed in cardiac catheterization laboratory
• Ask for history of allergies particularly to iodine containing substance or shellfish
• Shave following areas:

Wrists, arms and axillae

Bilateral groin

Pubic area

• Make sure blood is collected and sent for HBsAg, HIV, etc. as ordered
• Instruct patient to withhold food and fluids for 8-12 hours prior to procedure
• Start IV line with heparin lock
• Remove jewelry, dentures/contact lens if any
• Make sure of blood investigation results are ready, e.g. HIV, HBsAg
• Assess baseline observations such as vital signs and neurovascular observations to both feet
• Administer morning dose of routine medications with sips of water
• Ask patient to empty bladder
• Administer premedications
• Send patient to catheterization laboratory with 5% dextrose 1 bottle, IV set 1, disposable 3 way 4, disposable 10 cc syringes 4, injection heparin 1 vial

DURING PROCEDURE

• Monitor vital signs
• Monitor for ventricular arrhythmias
• Watch for signs for allergic reaction to contrast dye
• Instruct patient to inform physician, nurse if chest pain develops
• Keep emergency equipment ready
• Provide reassurance throughout procedure

POST-CATHETERIZATION CARE

• Transfer patient from stretcher to bed gently
• Assess vital signs every 30 minutes for 2 hours initially and then hurly till stable
• Instruct patient about strict bed rest for 12-24 hours
• Advise to keep affected extremity straight to prevent bleeding
• Check dressing over puncture site for bleeding or signs of hematoma
• Assess neurovascular observations which include peripheral pulse, color warming, and sensation in affected extremity and compare with unaffected extremity
• Monitor cardiac rhythm for arrhythmias
• Encourage fluid intake for adequate fluid replacement and renal elimination of contrast
• Provide urinal bedpan whenever needed
• Observe for nausea, vomiting and other signs of hypersensitivity to contrast
• Encourage normal diet after 3 to 4 hours, if no vomiting
• Remove pressure bandage after 24 hours and watch for hematoma formation and pseduoaneurysms
• Maintain strict intake and output chart
• Instruct to restrict activities for 2 days after discharge

TENSILON TEST (EDROPHONIUM BROMIDE) – Indications, Purpose, Equipment, Procedure, Method, Follow-up, Cholinergic Side Effects of Edrophonium, Positive Test, Utility of Tensilon Test, False Positive Results, Client Preparation, Preparation and After Care

The Tensilon test is a pharmacological challenge study performed to assist in the diagnosis of myasthenia gravis. The drug used in edrophonium chloride (Tensilon), a short-acting form of the drug used to treat this disorder. The test involves the IV administration of the drug before and during the performance of various muscular movements and the evaluation of these movements for changes in muscle strength. A positive diagnosis is made when the administration of the drug results in an improvement in muscle function. A negative diagnosis is made if muscle fasciculations occur as a result of the drug

Myasthenia gravis (MG) is a disease affecting the neuromuscular junction. It is caused by a deficiency of acetylcholine receptor sites on the muscle side of the junction. It is thought that the reduction in these sites is caused by an autoimmune response that blocks the receptor site and is responsible for receptor destruction. The most prominent symptom of the disease is weakness of the involved muscles, which progresses in severity to all areas of the body

Interfering factors: corticosteroids, muscle relaxants, and anticholinergics, which can alter test results by their effect on muscle function or on the action of Tensilon

INDICATIONS

• Diagnosing myasthenia gravis when fatigue and muscle weakness are present, as revealed by an immediate improvement after injection of Tensilon
• Monitoring medication regimen of oral anti-cholinesterase to determine whether increase in dose is advised, as revealed by an improvement in muscle strength after IV Tensilon
• Determining whether an overdose is present, which can place the client in cholinergic crisis, as revealed by an exaggeration of muscle weakness after IV Tensilon

Contraindications: breathing difficulties or apneic conditions, because the disease can cause respiratory difficulties severe enough to require ventilatory support

Acetylcholine is a neurotransmitter chemical that nerve cells release to stimulate your muscles. People with a chronic disease called myasthenia

Definition: A provocative best to diagnose myasthenia gravis, using endroonium bromide

PURPOSE

• To diagnose myasthenia gravis
• To differentiate between myasthenia and cholinergic crisis

EQUIPMENT

• Injection tray with tensilon
• Atropine
• Tuberculin syringe
• 1.5 ml syringe
• 500 ml saline or dextrose as ordered
• Tourniquet
• Spirit
• Cotton balls
• K-basin
• Duster
• Resuscitation equipment
• 12 ventilator and         ECG monitor

PROCEDURE

A medicine called Tensilon (also called edrophonium) or a dummy medicine (inactive placebo) is given during this test. The health care provider gives the medicine through one of your veins (intravenously, through an IV). You may also be given a medicine called atropine before receiving Tensilon so that you do not know you are getting the medicine. You will be asked to perform some muscle movements over and over again, such as crossing and uncrossing your legs or getting up from a sitting position in a chair. The provider will check whether the Tensilon improves your muscle strength. If you have weakness of the eye or face muscles, the effect of the Tensilon on this will also be monitored. The test may be repeated and you may have other Tensilon tests to help tell the difference between myasthenia gravis and other conditions

METHOD

Initially

• Dosing: 2 mg of edrophonium is administered intravenously as a test dose
• Monitoring heart rate: bradycardia or ventricular fibrillation may develop

FOLLOW-UP

• After observing for about 2 minutes, if no clear response develops
• Up to 8 additional mg of edrophonium is injected

A double-blind protocol with a saline injection as placebo has been advocated

Testing should be performed with patient free of all cholinesterase-inhibitor medications

CHOLINERGIC SIDE EFFECTS OF EDROPHONIUM

• May include increased salivation and lacrimation, mild sweating, flushing, urgency and perioral fasciculations,
• Atropine should be readily available to reverse effects of edrophonium in case of hemodynamic instability
• Extra precautions are especially important in elderly patients

POSITIVE TEST

• Most myasthenic muscles respond in 30 to 45 seconds after injection
• Improvement in strength that may persist for up to 5 minutes
• Requires objective improvement in muscle strength
• Subjective or minor responses, such as reduction of a sense of fatigue, should not be over interpreted

UTILITY OF TENSILON TEST

• Only useful in patients with objective, preferably measurable, findings on physical examination
• Rarely helpful in the diagnostic evaluation of equivocal cases of MG
• Sensitivity for MG is relatively low (60%) compared to other diagnostic tests
• Tensilon testing should not be used to determine adjustments in the dose of pyridostigmine

FALSE POSITIVE RESULTS

• Can occur in patients with LES, ALS or even localized, intracranial mass lesions
• Positive testing does not necessarily predict response to a longer-acting anticholinesterase drug

CLIENT PREPARATION

• Instruct the client that the test will aid in finding actual causes of muscle weakness
• Check whether the client is taking anticholinesterases drug, whether allergic to any drugs and whether any respiratory problems
• Inform that test will done in semi-intensive care unit

PREPARATION

• Place the client in comfortable position on treatment table
• Load 10 ml of tensilon into syringe with 10 ml of normal saline and administer 2 mg initially
• Watch for respiratory distress and other symptoms
• Inject the remaining 8 ml if no symptoms appear
• Assist in giving exercise to client to reduce fatigue of muscles
• Assist for repeating test if no improvement is found within 5 minutes
• Watch for respiratory failure
• Keep resuscitation equipment and ventilator ready
• Administer adrenaline 2 mg as prophylactic measures

AFTER CARE

• Keep the client in semi ICU for a few hours to monitor for complications, e.g. respiratory failure
• Watch for cardiac changes, e.g. tachycardia
• Assess neurological signs every half hourly for 2 hours
• Transfer the client ward if stable

MYELOGRAPHY – Definition, Purpose, Indications, General Instructions, Client Preparation, Procedure and After Care

NURSING PROCEDURES LIST CLICK HERE

Myelography or myelogram is an X-ray of the spinal subarachnoid space taken after an opaque or air is injected into the spinal subarachnoid space through a spinal puncture. It is also a diagnostic procedure used to visualize the lumbar, thoracic or cervical areas or whole spinal axes for diagnosis of a spinal tumor, a herniated intervertebral disc or a ruptured disc

DEFINITION

Myelography is an X-ray examination of the spinal subarachnoid space taken after an opaque medium or air is injected into the spinal subarachnoid space through a spinal puncture. It shows any distortion of the spinal cord or spinal dural sac caused by tumors, cysts, herniated intervertebral discs or other lesions

PURPOSE

• To identify space-occupying lesions of the spinal cord
• To help diagnosis a herniated nucleus pulposus
• To diagnose intramedullary tumors
• To identify the traumatic lesion and cysts of the vertebrae or the spinal cord

INDICATIONS

• Spinal cord tumors
• Traumatic lesions of the spinal cord
• Herniated intervertebral disc

GENERAL INSTRUCTIONS

• The client should be prepared physiologically and psychologically
• Strict aseptic technique should be followed throughout the procedure
• The client should be informed that the X-ray table may be titled in varying positions during the study
• The commonly used dyes are mertrizamide (amipaque) and iophendylate (pantoopaque) so the sensitivity should be checked
• Instruct the client to remain supine for 12 to 24 hours after the procedure
• Inform the client that the procedure is done in X-ray department

CLIENT PREPARATION

• Explain the procedure to the patient and relatives
• Obtain informed consent
• The meal that would normally be eaten prior to the procedure is omitted
• The client may be given a light sedative to help cooperate
• Sensitivity test for the dye must be checked

PROCEDURE

• Place the client on the X-ray table
• Position the client for lumbar puncture
• LP needle is inserted L4-L5
• Approximately 10 ml of CSF is removed
• Water soluble nonionic contrast medium is then injected
• The table is titled to allow the column of the dye to move up and down within the subarachnoid space
• By minimal changes in position of the table and patient, various regions of the spine are screened and films taken at appropriate levels

AFTER CARE

• Keep the client strict bed rest
• Position the client’s head elevated 30 degree
• Check the neurological and vital signs
• Encourage more oral fluids
• Provide light soft diet if no nausea and vomiting
• Mild analgesics may be given if headache persists
• Check the client’s ability to void
• Observe for fever, stiff neck, photophobia or the signs of chemical or bacterial meningitis

LUMBAR PUNCTURE – Definition, Purpose, Indications, General Instructions, Special Considerations, Equipment Needed, Queckensted’t Test (Lumbar Manometric Test), After Care, Contraindications and Complications

Lumbar puncture (LP) is an invasive procedure; it is carried out by inserting a needle into the lumbar subarachnoid space directly into the intervertebral space in order to withdraw cerebrospinal fluid for diagnostic and therapeutic purposes. The normal range of spinal fluid pressure with the patient in a lateral position is 70 mm to 180 mm of water. Pressure over 200 mm of water is considered abnormal

DEFINITION

Lumbar puncture is a percutaneous puncture entering the spinal column’s subarachnoid space at the vertebral interspaces L3-L4 or L4-L5. A lumbar puncture is performed for cerebrospinal fluid (CSF) pressure measurement, withdrawal of a CSF specimen for analysis and the introduction of contrast media for diagnosis tests

PURPOSE

• To obtain cerebrospinal fluid analysis and to evaluate for signs of infection or hemorrhage
• To measure the intracranial pressure and relive the pressure if it is high
• To administer spinal anesthesia for surgeries
• For intrathecal injection of antibacterial and other drugs
• For evaluation of spinal dynamics for signs of blockage of CSF flow due to tumor or other pathology of spinal cord

INDICATIONS

• To reduce intracranial pressure (ICP) after a spontaneous hemorrhage, by releasing CSF
• To help diagnosis diffuse or disseminated infections of the nervous system or meninges, subarachnoid hemorrhage or demyelinating diseases
• To introduce anesthetic, antibiotics or other therapeutic drugs into the area
• To identify degree of subarachanoid blockage

GENERAL INSTRUCTIONS

• Follow the strict aseptic technique
• Site used for lumbar puncture is between third and fourth and fifth lumbar vertebra in adults and still lower in children
• The position used is side lying with knees drawn to the chin or sitting position with head and knees are flexed
• All the articles used for lumbar puncture should be autoclaved
• The client should be placed near the edge of the bed or table for the convenience of the doctor
• The lumbar puncture needle should be sharp and straight
• The client should empty his bowel and bladder before the procedure
• Use restrain the uni-cooperative clients and children
• The pressure reading taken when the client is relaxed and the fluid level remains fairly constant in the monometer
• Inform the client not to move during the procedure
• Vital signs should be recorded before and after the procedure
• CSF collected should be sent to laboratory immediately along with laboratory request form
• The drug to be injected must be warmed to the body temperature before administration

SPECIAL CONSIDERATIONS

• Do not perform when increased ICP may be caused by a expanding lesion, such as a subdural hematoma after a head injury
• Perform cautiously in client with suspected spinal cord or brain tumor. Procedure may cause fatal cerebellar tonsillar herniation or compression of medulla of the client:

Explain the procedure to the client and relatives to reduce their fear and anxiety

Obtain a written consent for the client or relatives

Instruct the client not to move during the procedure

Help the client to wear a clean and loose garment

EQUIPMENT NEEDED

• A sterile tray containing – LP needles (19-21), sponge holding forceps, 5 ml syringe with needle, two small sterile bowls, three specimen bottles, a spinal sheet, sterile cotton balls, gauze pieces and cotton pads, a three way adapter and monometer tubing, sterile gown, mask and gloves
• A tray containing – Mackintosh and a towel, kidney tray and paper bag, skin antiseptics (spirit, betadine and tincture benzoine), local anesthetic agent xylocaine 1-2 percentage), sterile normal saline, band aid, hand washing articles and screen

Procedure: (done by the doctor and nurse has to assist)

• Explain the procedure
• Position the client
• Wash hands and wear sterile gloves
• Ask the assistant to open the sterile LP set
• Clean the site with spirit and betadine
• Spread the sterile center hole towel
• Puncture the subarachnoid space by accurate identification of L4 and L5 intervertebral spaces
• The initial pressure reading is obtained by measuring the level of the fluid column after it comes to rest
• Collect 2-3 ml of spinal fluid in each of the three test tubes
• After the needle is withdrawn apply pressure at the site for a few minutes
• Apply tincture benzoin seal

QUECKENSTEDT’S TEST (LUMBAR MANOMETRIC TEST)

• This test is done when a spinal subarachnoid block (by tumor, vertebral fracture or dislocation) is suspected
• Pressure may be applied manually by pressing firmly and simultaneously upon the jugular veins on the each side of the neck for a period of 10 seconds or blood pressure cuff may be placed around the client’s neck and inflated to a pressure of 20 mm Hg
• The increase in the pressure caused by the compression is noted
• Then the pressure is released and pressure reading is made at 10 second intervals
• In normal persons, the cerebrospinal fluid pressure rises rapidly in response to compression of the jugular veins and returns quickly to normal when the compression is released
• A slow rise and fall in pressure indicates a partial block due to a lesion compressing the spinal subarachnoid pathways
• If there is no pressure change, a complete block is indicated. This test is done if an intracranial lesion is suspected

AFTER CARE

• Place the client flat for at least 6 hours
• Frequently monitor the neurological vital signs
• Encourage the client to drink plenty of fluids
• Observe puncture site for edema, hematoma and CSF leakage
• Foot end of the bed should elevated
• Replace the articles after washing

CONTRAINDICATIONS

• Cutaneous or osseous infection at the site of lumbar puncture
• When the client has drastically increased LCP, lumbar puncture may result in brainstem compression

COMPLICATIONS

• Post-lumbar puncture headache that becomes severe when the client sits and stands but decreases in a supine position
• Herniation or coning of brain through foramen magnum
• Local pain, edema and hematoma at the punctured site
• Trauma to the tissue at the LP site
• Injury to spinal cord and spinal nerves
• Infection