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Tracheostomy Nursing Care in the Critical Care Setting

Tracheostomy is a procedure in which an artificial opening a.k.a. stoma is created at the level of the second or third cartilaginous ring from where the tracheo-bronchial tree is accessed and a tracheostomy tube is inserted. Proper tracheostomy nursing care in the critical care setting ensures patient safety.

Retrieved from https://entokey.com/laryngeal-anatomy/ (left) and https://www.pinterest.com/pin/83387030589729256/ (right) on 1st November 2022

Tracheostomy indications

airway obstruction in relation to problems with tongue, pharynx, larynx, trachea and oesophagus
anaphylaxis
foreign body
facial trauma
facial or respiratory burns
prior to extensive head and neck surgery
vocal cord paralysis
sleep apnoea
instable cervical spine
inflammation
tumor
congenital anomalies (structural or functional anomalies which occur in-utero)

NOTE: Tracheostomy is preferred as a prolonged airway maintenance and ventilation method. It is also used in cases of failed and/or repeated intubation, following intubation complications, and where there is need for deep secretion removal.

Tracheostomy Advantages

less restricting for the patient
enables swallowing
enables better communication
less sedation requirement
allows better mouth hygiene
helps avoid upper airway complications related to ETT use
easier secretion removal
reduces anatomical dead space (shorter, wider and less curved tube = better breathing = quicker weaning from ventilator use)

Tracheostomy Preparation & Surgical Procedure

explain tracheostomy procedure to the patient and accompanying relatives
gain operation consent
ensure availability of needed drugs (sedatives/analgesics/muscle relaxants), blood in reserve, suction equipment, cautery machine (helps in cutting and stopping bleeding immediately and effectively), and procedure trolley
help patient in supine position with blanket roll between shoulder blades to ensure neck is adequately exposed.

an incision is made between the sternal notch and cricoid cartilage
a midline vertical incision is made to divide strap muscles
thyroid isthmus between ligatures is divided
cricoid is elevated along with the cricoid hook
an incision is made through the tracheal wall
a tracheostomy tube is inserted while the endotracheal tube is withdrawn
cuff is inflated
keyhole dressing is applied
tube is secured either with tape around the neck or with stay sutures
tube is connected to the ventilator tubing

tracheostomy nursing care — Retrieved from https://www.surgeryencyclopedia.com/St-Wr/Tracheotomy.html on 1st November 2022

Percutaneous Dilational Tracheostomy

As seen above, a surgical tracheostomy requires a surgical dissection to be made down to the trachea, the creation of a window in the trachea with the insertion of a tracheostomy tube for ventilation…

Compared to surgical technique, the percutaneous dilational tracheostomy (PDT) uses a modified Seldinger technique where the trachea is accessed with a needle and then a guidewire is inserted. The tracheostomy tube is introduced over the guidewire after dilation.
Rashid & Islam, 2017

Thus, a percutaneous dilational tracheostomy avoids surgical incision, is less traumatic, and carries a lower bleeding risk.

a large bore needle is inserted into the tracheal lumen between the 2nd and 3rd ring
a flexible guidewire is then inserted
serial dilations are made
tube is inserted

NOTE: Ideally, a percutaneous dilational tracheostomy are done under ultrasound or bronchoscopy guidance. The procedure is contraindicated in patients with goitre, obesity, and acute upper airway obstruction.

Tracheostomy Complications

During placement of tracheostomy, arising complications may include:

haemorrhage (due to the area being very vascular)
pneumothorax (accidental pleura laceration)
oesophageal trauma
laryngeal nerve injury (may cause hoarseness, difficulty in swallowing or breathing, or loss of voice)
vagal nerve stimulation (may lead to bradycardia, hypotention, or cardiac arrest)
incorrect placement

Post-op complications following a tracheostomy may include:

haemorrhage
aspiration
wound infection
infection in the trachea
infection in the lungs
tube obstruction caused by blood or secretions
tube displacement
subcutaneous emphysema (usually this is solved without any interventions)

Late complications related to tracheostomy use may include:

tracheal stenosis (abnormal narrowing of the trachea which restricts the patient’s ability to breathe)
tracheo-oesophageal fistula (abnormal connection between the trachea and oesophagus which causes swallowed liquids or food to be aspirated into the lungs)
tracheoinnominate artery erosion by cuff or tip of tube (may require resuscitative and operative measures)
stoma does not close following removal of tube
overgranulation and scarring

Types of Tracheostomy Tubes

Retrieved from https://www.exportersindia.com/product-detail/white-fenestrated-tracheostomy-tube-6433292.htm (left) and https://www.magonlinelibrary.com/doi/abs/10.12968/bjon.2019.28.16.1060 (right) on 1st November 2022

Cuffed Tube with Disposable Inner Cannula – Used to obtain a closed circuit for ventilation.

Cuff should be inflated when using with ventilators
Cuff should be inflated just enough to allow minimal airleak
Cuff should be deflated if patient uses a speaking valve
Cuff pressure should be checked twice a day
Inner cannula is disposable

Retrieved from https://www.hopkinsmedicine.org/tracheostomy/about/types.html on 12th November 2022

Cuffed Tube with Reusable Inner Cannula – Used to obtain a closed circuit for ventilation.

Cuff should be inflated when using with ventilators
Cuff should be inflated just enough to allow minimal airleak
Cuff should be deflated if patient uses a speaking valve
Cuff pressure should be checked twice a day
Inner cannula is not disposable; you can reuse it after cleaning it thoroughly

Cuffless Tube with Disposable Inner Cannula – Used for patients with tracheal problems and for patients who are ready for decannulation.

Save the decannulation plug if the patient is close to getting decannulated
Patient may be able to eat and may be able to talk without a speaking valve
Inner cannula is disposable

Cuffed Tube with Reusable Inner Cannula – Used for patients with tracheal problems and for patients who are ready for decannulation.

Save the decannulation plug if the patient is close to getting decannulated
Patient may be able to eat and may be able to speak without a speaking valve
Inner cannula is not disposable; you can reuse it after cleaning it thoroughly

Fenestrated Cuffed Tracheostomy Tube – Used for patients who are on the ventilator but are not able to tolerate a speaking valve to speak.

There is a high risk for granuloma formation at the site of the fenestration (hole)
There is a higher risk for aspirating secretions
It may be difficult to ventilate the patient adequately

Fenestrated Cuffless Tracheostomy Tube – Used for patients who have difficulty using a speaking valve.

There is a high risk for granuloma formation at the site of the fenestration (hole)

Metal Tracheostomy Tube – Not used as frequently anymore. Many of the patients who received a tracheostomy years ago still choose to continue using the metal tracheostomy tubes.

Patients cannot get a MRI
One needs to notify the security personnel at the airport prior to metal detection screening

CUFFED VS NON-CUFFED VS FENESTRATED

SINGLE VS DOUBLE TUBE

Double lumen tubes contain an inner cannula which can be removed for cleaning.

TRACHEOSTOMY VS LARYNGECTOMY

SHILEY TUBE

Upper Airway Bypass Effects

In normal upper airway functions there is humidification, warming and filtration of inspired air, ability to taste, smell and swallow, speech production by the passing of exhaled air through the larynx, and involvement in the cough reflex.

When bypassing the upper airway, lack of humidification leads to impaired mucociliary function, thicker secretions which can easily cause tube obstruction, as well as atelectasis (partial or full lung collapse) and infection. Similarly, air below body temperature may cause bronchoconstriction, reduced air flow, decreased PO2 (partial pressure of oxygen) and decreased SaO2 (oxygen saturation of arterial blood).

Humidification

Requirements for optimal gas exchange, which are in normal circumstances achieved through the upper airway, include:

a temperature of 37 degrees celsius
100% humidity
filtered air

Adequate humidification may reduce the need for suctioning, thus, in situations where the upper airway is bypassed by an ETT or tracheostomy, an external method providing warmth, humidity and filtration is needed.

Through an external humidification system, inspired gas is passed over heated water with a set temperature of about 60 degrees celsius. As the air passes along the tubing, it cools down to around 37 degrees celsius when reaching the patient.

Although this system provides a setting similar to what is required for optimal gas exchange, it poses a couple of problems: it requires equipment care, it restricts patient mobility, and it may also become an infection source for the patient.

The HME Filter – Heat Moisture Exchanger

HME filters a.k.a. heat moisture exchanger filters are devices used in patients who are mechanically ventilated to help prevent mucus plugging and endotracheal tube occlusion due to lack of humidification.

HMEs are made of hydrophylic material which retains heat and moisture in exhaled air, which are then recycled in subsequent inspirations, following filtration of inspired air.

HMEs improve patient mobility and lower risk of infection. However, they can still become easily blocked by secretions, and so, require frequent filter changes (usually changed within a couple of days based on manufacturer’s recommendations) or even cessation of use in case of profuse secretions.

Suctioning in Airway Management

Secretions are cleared by coughing under normal conditions. Cough involves pressure build-up in the lungs which depends on closure of the glottis. The use of a tube prevents the patient from increasing enough abdominal pressure to produce a cough that clears secretions in the airway. Additionally, the tube may also cause irritation which leads to increased sputum production.

Suctioning is a procedure that needs to be performed as often as required based on the patient’s individual needs, so as to clear secretions and maintain a patent tube.

suctioning should not be performed routinely but as needed
suctioning should be performed using a sterile technique
suctioning can be scary and unpleasant for the patient, thus, it needs to be performed with confidence and speed

Suctioning Indications

coughing
respiratory distress
increased peak airway pressure
decreased SaO2 (oxygen saturation of arterial blood) and PO2 (partial pressure of oxygen)
audible and/or visible secretions
suspected aspiration
signs of discomfort

Open Suctioning Procedure

explain procedure to the patient
provide the patient with hyperoxygenation at 100% oxygen
whilst keeping the catheter in its wrapper, attach it to suction tubing and switch it on
wear mask and sterile suction glove
insert catheter up to 1cm more than the tube length
apply suction on the way out; oropharyngeal cavity may also need suctioning
hyperoxygenate again
monitor patient

NOTES:

do not exceed 15 seconds in performing suctioning so as to prevent hypoxia
maintain aseptic technique whilst performing procedure
catheter width should not exceed half the tube’s diameter
catheters with multiple eyes produce less damage
negative pressure should not exceed 120mmHg
instillation of saline is not recommended any more, however, saline nebulisation may help in loosening secretions

Suctioning Complications

HYPOXAEMIA – arterial blood oxygen level lower than normal: happens due to the patient being disconnected from the oxygen source whilst suctioning is being performed; reduce risk by performing suctioning for not longer than 15 seconds and ideally using a closed suction system instead of the open suction one.

ATELECTASIS – complete or partial collapse of the entire lung or lobe of the lung: happens when excessive pressure is being used while suctioning; reduce risk by ensuring that pressure does not exceed 120mmHg.

BRONCHOSPASM – tightening of the muscles lining the bronchi a.k.a. airway tightening: happens due to catheter use stimulating the airway.

DYSRHYTHMIAS – abnormal or irregular heartbeat (especially bradycardia following suctioning): happens due to hypoxaemia and vagal stimulation.

HAEMODYNAMIC CHANGES – increased blood pressure and intracranial pressure; reduce risk by avoiding suctioning in patients with head injury.

TRACHEAL MUCOSA TRAUMA – reduce risk by avoiding deep suctioning, large catheters and excessive pressure.

INFECTION – reduce risk by using strict aseptic technique and using a closed suction system. NOTE: send specimens for C+S if infection is suspected.

Closed Tracheal Suctioning Procedure

Using a closed tracheal suctioning procedure allows suctioning of the airways without the need for disconnecting the patient from the ventilator. This is done by attaching the suction catheter in plastic sleeve directly to the ventilator tubing.

Advantages:

maintains oxygenation and PEEP (Positive End Expiratory Pressure) during suction
reduces the risk of complications related to hypoxaemia
provides HCPs with protection from secretions

Disadvantages:

possible auto-contamination (reduce risk by cleaning catheter after each use and change every 24 hours)
inadequate removal of secretions
extra weight on ventilator tubings may cause an unintentional extubation
expensive

Cuff Management

The use of a cuff provides a seal in mechanical ventilation of a patient. This seal provides protection from gross aspiration. However, it does not offer complete protection from aspiration, and it may also disguise aspiration signs. Additionally, cuff exerts pressure on the oesophagus, anchoring the larynx, thus reducing laryngeal elevation. Considering all the above…

The patient with an inflated cuff should be kept nil-by-mouth! Provide needed nutrition through a nasogastric tube, a nasojejunal tube, gastrostomy, or jejunostomy. Important: assist the patient as needed to maintain oral hygiene!

Cuff used should be a high volume low pressure cuff. Cuff pressure should be checked at the start of every shift, after turning the patient, after physiotherapy, after dressing change and if a leak can be heard. Pressure should be kept between 15-25mmHg.

A low cuff pressure causes a drop in tidal volume due to leak of exhaled air around the tube, as well as possible aspiration of gastric content.

A high cuff pressure may create a fistula between the trachea and the oesophagus a.k.a. tracheoesophageal fistula, especially if a stiff nasogastric tube is being used on the patient. It may also cause obstruction of capillary blood flow within the tracheal wall, leading to pressure sore necrosis and tracheal stenosis following formation and healing of scar tissue.

Tracheostomy Communication Through Speaking Valves

In normal circumstances, speech is created by the passing of exhaled air through the vocal cords. Since tracheostomy tubes are inserted below the vocal cords, sound cannot be formed. This may cause the patient to become anxious and feeling isolated.

The nurse should provide reassurance to the patient by explaining that loss of sound being experienced is only temporary, and voice returns once the tracheostomy tube is removed. The nurse should also encourage the patient to use different ways of communication whilst with a tracheostomy tube is inserted, such as using electronic devices, paper and pen, or speaking valves.

Speaking Valve Use

When using a speaking valve, ensure that the patient has a good gag reflex and that he is using either a non-cuffed or a fenestrated tube; if patient is using a cuffed tube, ensure that the cuff is totally deflated before attempting use of speaking valve
Upon inspiration, the valve opens, allowing air to be inhaled through the tracheostomy
Upon exhalation, the valve closes; air passes around the tube and through the vocal cords, enabling exhalation from the upper airway and voice production

NOTE: DO NOT USE A SPEAKING VALVE if the patient has poor lung compliance, in the case of excessive secretions, and if laryngeal or pharyngeal problems are present.

Tracheostomy Nursing Care – Wound Care & Tape Changes

The surgical wound needs to be kept clean and dry at all times. The wound dressing used needs to be changed daily or whenever it becomes soiled. The aseptic non-touch technique should be used whilst cleaning the wound with saline, including careful cleaning of the area underneath the flange. Note that between the patient’s neck and tape there needs to be a space for one to two fingers.

prepared equipment for an arising emergency

1 spare tube in the same size as the one being used
1 spare tube in a smaller size than the one being used
suction and suction catheters
oxygen
tracheostomy mask
securing tape
tracheal dilators
scissors
suture cutter
lubricating gel
syringe (to inflate cuff)
drugs and equipment for resuscitation
sterile keyhole dressing
non-sterile gloves

Tracheostomy Tube Change

A single lumen tracheostomy tube should be changed every 7-10 days so as to prevent obstruction. Other indications for a tracheostomy tube change include:

cuff failure
blockage within the tube
displacement of the tube
needing to change to a larger or smaller tube

Tracheostomy Weaning and Decannulation

A tracheostomy is no longer needed if:

the reason for a tracheostomy has been resolved
the patient is alert, stable, and self ventilating on air
the patient has no significant signs of airway obstruction
the patient is able to swallow and cough up secretions
the patient is able to maintain good oxygen saturation

In case of the above:

cuff is deflated
tube is occluded for 24 hours
if no respiratory distress is experienced by the patient, tube is removed
the stoma is covered with a small occlusive dressing

Important Tracheostomy Nursing Care Observations

monitor patient for bleeding or oozing
monitor patient for signs of infection and/or inflammation
monitor patient for evidence of tissue damage
monitor cuff pressure and ensure it is kept within normal limits
monitor amount, colour and consistency of secretions

Reference

Johns Hopkins Medicine (n/d). Tracheostomy Service. Retrieved from https://www.hopkinsmedicine.org/tracheostomy/about/types.html on 12th November 2022

Rashid, A. O., & Islam, S. (2017). Percutaneous tracheostomy: a comprehensive review. Journal of thoracic disease, 9(Suppl 10), S1128–S1138. https://doi.org/10.21037/jtd.2017.09.33

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Critical Care Setting Haemodynamic and Respiratory Monitoring

In the critical care setting the nurse’s observatory role is crucial in maintaining optimum care of the critical patient, which is why, ideally, the nurse-patient ratio should be 1:1. Additionally, technology plays a very important role within the same setting. However, one must not forget the GI-GO paradigm, a.k.a. Garbage In, Garbage Out – whilst analytical technology can be very useful in critical care, produced data always depends on how well the data is collected.

Invasive Monitoring Equipment in Critical Care

Invasive monitoring equipment used within the critical care setting includes:

invasive (arterial) catheter – a small cannula, usually containing an anti-reflux switch, which is inserted (sometimes with the help of a guidewire) into an artery to constantly monitor a patient’s blood pressure
high pressure tubing – helps preserve pressure and prevent loss of pressure between the patient’s vein or artery and the transducer
transducer – delivers numerical blood pressure readings and arterial pressure waveforms with every heartbeat to a bedside monitor by sensing blood-generated pressure passing past a catheter tip; readings and waveforms delivered are dynamic and change with every beat of the cardiac cycle; the transducer and line are attached to the arterial line via a connector, allowing the changing of the transducer set (ideally every 96 hours) without requiring re-insertion of the arterial line
flush system – helps keep the line clear and avoid blood backflow through the catheter; saline bag is used under the pressure bag, usually with 2 units of heparin per cc, to help keep the artery open UNLESS the patient has a known allergy to heparin; NOTE: even a little bit of heparin can cause heparin-induced thrombocytopaenia (immune system causes platelets to clot in the presence of heparin, resulting in platelet levels dropping), so if the patient’s platelet count drops for no apparent reason, remove the heparinised saline bag and change to saline bag instead
monitor – commonly displays ECG, heart rate, intermittent cuff blood pressure, arterial blood pressure, internal temperature, peripheral venous oxygen saturation, partial pressure of CO²

Critical Care Setting Haemodynamic and Respiratory Monitoring — Retrieved from https://tinyurl.com/3zm7dt7t on 10th October 2022

Arterial Catheter Indications

An arterial catheter is indicated in instances:

when continuous blood pressure monitoring is required eg. during surgery, during use of vasoactive medications, or in the case of compromised cardiac output, fluid volume, and tissue perfusion
when patients require frequent arterial blood gas sampling eg. if they are experiencing respiratory failure or are on mechanical ventilation

Arterial Line Placement Sites

Radial Artery – easily accessible site which is also considered to be safe since collateral hand circulation is supplied by the ulnar artery – circulation within both these arteries can be checked via an allens test; this site is also preferred due to a decreased risk of complications when compared to other larger vessels
Brachial Artery – located close to joint thus blood flow may be easily interrupted
Femoral Artery – large vessel which, due to its location, is difficult to observe on a continuous basis
Dorsalis Pedis Artery – needs to be avoided if the patient has severe peripheral vascular disease

Allens Test

Arterial Blood Pressure Reading

When using an arterial catheter, a constant second by second reading of the systolic (SBP), diastolic (DBP), and the mean arterial blood pressure (MAP) can be provided. The MAP is a more accurate indicator of the patient’s condition since it also reflects the perfusion rate of essential organs such as the kidneys.

The MAP is usually calculated automatically by most monitors. However, it can be calculated using the following formula:

Retrieved from https://clinicalview.gehealthcare.com/white-paper/measuring-mean-arterial-pressure-choosing-most-accurate-method on 10th October 2022

Arterial Waveform

Respiratory Swing

The respiratory swing is more pronounced in the case of mechanical ventilation. It can help indicate dehydration.

Retrieved from https://secure.library.leicestershospitals.nhs.uk/PAGL/Shared%20Documents/Arterial%20Line%20Waveform%20Interpretation%20UHL%20Paediatric%20Intensive%20Care%20Guideline.pdf on 10th October 2022

Care of the Patient with an Arterial Line

perform regular checks for loose connections, blood backflow, a deflated pressure bag, or lack of fluid in the flush bag
ensure that the arterial catheter site is easily accessible and always visible
DO NOT inject any medication in the arterial catheter!

A patient with an arterial line may eventually develop complications. Monitor the patient for:

Infection – perform frequent patient checks, noting any redness, discharge, warmth to touch, or fever; preventative measures include using an aseptic non-touch technique during insertion of catheter, blood sampling, and line maintenance
Haemorrhage – perform frequent checks at the arterial catheter insertion site especially if it was inserted into the femoral artery since this is a large vessel
Thrombosis – perform frequent checks on patient’s legs, taking note of the colour, pulse, temperature and sensation; preventative measures include adequate flushing following blood sampling, and using the smallest catheter possible during the insertion procedure

Levelling and re-zeroing

The transducer system must be leveled and zeroed to provide accurate haemodynamic values, since this eliminates atmospheric pressure effects. The exact point where the 4th intercostal space crosses the mid-axillary line is referred to as the Phlebostatic Axis. The nurse should ensure that zeroing is done at the beginning of every shift, as well as after any major positional changes.

How To Remove Arterial Line

perform hand hygiene
don gloves
gather necessary equipment
remove any dressings and sutures if present
whilst applying firm pressure to insertion site pull out the arterial line gently
apply manual pressure and elevate limb
apply small occlusive dressing which allows periodic observation for blood leakage

NOTE: an adequate blood pressure reading doesn’t automatically signify adequate perfusion…always take into consideration the whole clinical picture, biochemical values, along with haemodynamic parameters.

NOTE: additional monitoring equipment can also be used along with the arterial line to measure cardiac output.

Central Venous Catheters CVC

Central Venous Catheters are indwelling catheters within the superior vena cava, inferior vena cava, right atrium, or any large vein leading to these vessels. They are sought in the case of:

administration of large amounts of fluid
administration of vesicant drugs (drugs that can cause tissue necrosis or blister formation if accidentally infused into tissue surrounding vein)
total parenteral nutrition
repeated venous blood sampling
measurement of pressure within the right atrium (Central Venous Pressure a.k.a. CVP) – this provides the measurement of the right atrium filling pressure, and indicates right ventricular function.

CVCs are inserted via the:

internal jugular veins
subclavian veins
femoral veins

Retrieved from https://www.schn.health.nsw.gov.au/_policies/pdf/2019-182.pdf on 14th October 2022

CVCs usually have 3 or 5 lumens. The distal port is used for monitoring of the CVP, however, it can also be used to administer blood products since it is the biggest port in a CVC. The other ports are used for fluid or drug administration. CVC line requires priming by approximately 1ml of fluid.

In a triple port lumen, the brown port opens up distally (at the tip), the blue port is the medial one, and the white port opens up proximally. If TPN is planned for the patient, it cannot be used intermittently with other infusions. Once TPN is stopped from being run through a particular port for any reason, and another infusion or medication is run instead, TPN cannot be re-administered again through that port.

NOTE: Always label CVC catheters and include insertion date! Note that central lines should be removed within a week from insertion.

Central Venous Catheter Insertion

provide patient with information about the procedure and address any questions or concerns
patient is positioned head down
patient’s skin is prepared for insertion
local anaesthetic is administered
preferred vein is located by needle and syringe
a guide wire is introduced through the needle, after which the needle is removed
CVC is introduced over the guide wire, and is then attached to primed system
CVC is sutured in place
a chest x-ray is performed to confirm correct placement

Central Line Dressing Change

Possible CVC Insertion Complications

pneumothorax – lung collapse following air leakage into the pleural space between the lung and chest wall
right atrium perforation
cardiac tamponade – when the pericardial space fills up with blood or other fluid, putting pressure on the heart, reducing blood pumping activity whilst causing a drop in blood pressure
arterial puncture
haemorrhage
air embolus

NOTE: preventative measures pre-procedure include positioning the patient in the Trendelberg position for both insertion and removal, and performing a chest x-ray following CVC insertion.

Other Complications related to CVC

CVC occlusion – may happen due to mechanical obstruction, precipitation of medications or parenteral nutrition, or due to thrombosis
CVC displacement
air entering the system (always check connections and taps)
local infection
systemic infection

NOTE: preventative measures for infection include adequate and correct hand hygiene, using an aseptic technique whilst handling the CVC, and replacing catheter when needed or required.

CVC Removal

CVCs pose a great risk of infection and are considered as major causes of morbidity and mortality. Additionally, they are also the main source of bacteraemia and septicaemia in hospitalised patients. Thus, CVCs should be removed as soon as possible.

ensure that no medication or fluids are being administered to the patient and/or listed in the patient’s treatment chart
use an aseptic non-touch technique
remove dressing and cut sutures
place patient head-down and lying flat
using the valsava maneuver, ask patient to hold his breath while you slowly remove the catheter; if resistance is felt on removal seek further help
apply pressure to the punctured site until bleeding stops
use an air occlusive dressing for the first 24 hours
if required send tip of CVC for culture and sensitivity

CVP Central Venous Pressure Measurement

Central Venous Pressure measurement, which is transduced electronically through the use of the CVC, should read between 0-8mmHg in normally breathing patients, and higher in mechanically ventilated patients. Attention should be given more to the measurement trend rather than individual readings.

The main limitation of the CVP measurement is that it does not initially reflect left ventricular dysfunction.

Whilst traditionally CVP monitoring was used to assess a patient’s fluid status on which hydration management was decided, studies have shown no correlation between CVP and preload (left ventricular end diastolic volume). Thus, CVP measurements should no longer be relied upon when making clinical decisions on patient fluid management (Marik et al., 2008).

Patient Monitoring – Non-Invasive & Minimally Invasive Techniques in Critical care

minimally invasive using data from arterial or CPV lines, a special type of transducer or catheter
calculations based on arterial waveform and patient demographic data such as weight, sex, age, and height
calculates CO (cardiac output), CI (cardiac index), SV (stroke volume), SVI (stroke volume index) and SV Variation; if interfaced with CVP data, calculations of SVR (systemic vascular resistance) and SVRI (systemic vascular resistance index) are also produced (more info on listed terms here)
may be calibrated (eg. PiCCO) or non-calibrated (eg. Vigileo)

Vigileo / flotrac (non-calibrated)

Vigileo uses a normal arterial catheter without the need for intermittent calibration. However, it is not recommended in the case of arterial wave artefacts, compromised arterial cannula, intense peripheral vasoconstriction, or arrhythmias. It also does not measure advanced volumetrics which can provide accurate CO measuring in a non-invasive way.

Key parameters provided by a Vigileo include:

SV and SVI
CO (CO = SV x HR)
SVV – reflects preload and fluid responsiveness

Limitations can be imposed by spontaneous breaths, open chest, or arrhythmias.

Picco Monitoring (calibrated)

PiCCO, which stands for Pulse Contour Cardiac Output, combines pulse contour analysis with transpulmonary thermodilution using a Thermodilution Arterial Catheter, which is inserted preferably in the femoral artery, or else through the brachial, axillary, or radial artery (which requires a longer catheter).

Retrieved from https://www.getinge.com/int/products/picco/ on 14th October 2022

Transpulmonary thermodilution is picked up by a temperature sensor located at the catheter tip, whilst the arterial blood pressure ABP is measured through the pressure extension line.

The artery pressure curve provides the following parameters:

CCO (CCI) – Continuous Cardiac Output
SV (SVI) – Stroke Volume
SVR (SVRI) – Systemic Vascular Resistance
CPO (CPI) – Cardiac Power Output
SVV – Stroke Volume Variation
PPV – Pulse Pressure Variation
dPmx – Left Ventricular Contractility
HR – Heart Rate
pArt-M – Mean Arterial Blood Pressure
pArt-S – Systolic Arterial Blood Pressure
pArt-D – Diastolic Arterial Blood Pressure
CVP – Central Venous Pressure

The Intermittent Transpulmonary Thermodilution provides the following parameters:

Q – Cardiac Output / CI – Cardiac Index
GEDV (GEDI) – Global End-Diastolic Volume
EVLW (ELWI) 0 Extravascular Lung Water
GEF – Global Ejection Fraction
PVPI – Pulmonary Vascular Permeability Index
CFI (Cardiac Function Index
ITBV (ITBI) – Intrathoracic Blood Volume

GEDV and ITBV reflect PRELOAD – GEDV indicates end volume at rest in all 4 heart chambers and ITBV indicates the volume in heart and pulmonary vessels.

ELWI indicates the water content in the lungs, thus can clearly indicate pulmonary oedema, if present.

GEF indicates the ration of 4 stroke volumes divided by GEDV. It helps detect ventricular dysfunction, if present.

PICCO Setup & Monitor

Retrieved from http://mindray.sy/patient-monitors/ on 14th October 2022

PiCCO Advantages

Picco Disadvantages

cannot be used with an intra-aortic balloon pump
needs to be recalibrated whenever patient changes position, therapy or condition
EVLW is underestimated when it comes to use on obese patients and post-pneumonectomy patients
AAA (abdominal aortic aneurysm) raises GEDV and ITBB measurements

Haemodynamic and Volumetric Monitoring

Pulse Oximetry in Critical Care

Pulse Oximetry is a non-invasive method which monitors oxygen saturation (SaO₂). It indiates the percentage of haemoglobin bound to oxygen.

In normal healthy adults, oxygen saturation should be >96%.

Accurate pulse oximeter readings depend on whether it is positioned well on a patient’s finger, ear, toe or nose, and how good the patient’s peripheral circulation is. Similarly, if a patient is shivering, the pulse oximeter may not be able to pick up a signal. Nail varnish may also affect reading outcome. Additionally, pulse oximetry cannot differentiate between normal and abnormal haemoglobin, thus may result in false high readings.

NOTE: always interpret pulse oximeter readings in conjunction with shown waveform.

Capnography in Critical Care

Capnography measures exhaled carbon dioxide gas, depicting a squarish waveform. Its measurement approximates PaCO₂, usually being about 1-5mmHg lower than the actual PaCO₂.

Capnography is non-invasive.

Capnography is very useful in cases where the patient is suffering from a head injury or from intracranial hypertension.

Very low ETCO₂ values given through capnography can help indicate gastric intubation rather than an intended tracheal intubation.

With regards to CPR assessment, one should aim for a minimum of 10mmHg.

An increased disparity between PaCO₂ and ETCO₂ suggests poor pulmonary blood flow, poor cardiac output, or lung disease.

Reference

Marik, P. E., Baram, M., & Vahid, B. (2008). Does central venous pressure predict fluid responsiveness? A systematic review of the literature and the tale of seven mares. Chest, 134(1), 172–178. https://doi.org/10.1378/chest.07-2331

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