Care Lecture 3: Critical Care Skills

hemodynamic monitoring

the measurement of pressure, flow, and oxygenation within the cardiovascular system to assess heart function, fluid balance, and the effects of fluids and drugs on CO

1. blood (volume)

2. pump

3. vessels

what are the 3 key components of hemodynamic monitoring?

cardiac output (CO)

the volume of blood in liters pumped by the heart in 1 minute

systemic vascular resistance (SVR)

represents opposition encountered by the left ventricle

pulmonary vascular resistance (PVR)

represents opposition encountered by the right ventricle

preload

the volume within the ventricle at the end of diastole

↑ preload = ↑ O2 myocardium requirements

what is the relationship between preload and cardiac O2 requirements?

-↑ preload = ↑ intravascular volume, impaired myocardial contractility, ↑ afterload

-↓ preload = ↓ stroke volume, ↓ CO

what does a high and low preload indicate?

restrict fluids & give diuretics

what can be done to treat preload that is too high?

IV fluid bolus or blood infusion

what can be done to treat preload that is too low?

afterload

the force or resistance against which the heart pumps

↑ afterload = ↓ CO (inverse)

what is the relationship between afterload and CO?

-↑ afterload = ↓ CO, ↓ stroke volume

-↓ afterload = ↑ CO, ↑ stroke volume

what does a high and low afterload indicate?

too high = vasodilators

what can be done to treat afterload that is too high?

too low = vasopressors

what can be done to treat afterload that is too low?

-SOB

-weakness

-peripheral edema

-tachycardia

-dizziness

-confusion

-nausea

what are some clinical manifestations of increased cardiac output?

-low BP

-weak pulse

-cool extremities

-↓ urine output

-arrhythmia

-fatigue

-chest pain

what are some clinical manifestations of decreased cardiac output?

central venous pressure (CVP)

measurement of right ventricular preload that reflects the amount of blood returning to the heart and the ability of the heart to pump the blood into the arterial system

contractility

describes the strength of the heart muscle's contraction; strength of the cardiac muscle to push blood from the ventricles

too high = beta blocker

what do we do for contractility that is too high?

too low = inotropics

what do we do for contractility that is too low?

stroke volume

the amount of blood ejected from the heart in one contraction

-diuretics

-restrict fluids

-vasodilators

**goal = less fluid

if preload or central venous pressure (CVP) is high, what do we administer?

beta blockers

if stroke volume is high, what do we administer?

inotropes

if stroke volume is low, what do we administer?

vasodilators

if afterload or systemic vascular resistance (SVR) is high, what do we administer?

vasopressors

if afterload or systemic vascular resistance (SVR) is low, what do we administer?

inotropic drugs

class of medication that influences the force of muscular contractions, particularly contractility of the heart muscle

positive inotropes

type of inotropic drugs that increase contractility; results in ↑ SV and ↑ myocardial O2 requirements

-epinephrine

-norepinephrine

-dopamine

-dobutamine

-milrinone

what are some examples of positive inotropes?

negative inotropes

type of inotropic drugs that decrease the contractility of heart muscle

-calcium channel blockers

-β- adrenergic blockers

what are some examples of negative inotropes?

↑ afterload = ↑ cardiac workload

what is the relationship between afterload and cardiac workload?

reflects fluid volume status

what does central venous pressure (CVP) reflect?

by measuring right atrial pressure during ventricular filling

how does central venous pressure (CVP) measure preload?

hypovolemia or shock states

low central venous pressure (CVP) can indicate what?

-right sided HF

-cardiac tamponade

-pulmonary HTN

-PE

**high CVP = right ventricular failure or volume overload

high central venous pressure (CVP) can indicate what?

in right atrium or in vena cava close to heart

where is central venous pressure (CVP) measured?

2-8 mmHg

what value represents normal central venous pressure (CVP)?

arterial pressure

the force generated by the ejection of blood from the left ventricle into the arterial circulation

intra-arterial catheter (peripheral arterial line)

type of line that involves continuous monitoring of systolic, diastolic and mean arterial pressure (MAP)

70-105 mmHg

what value represents normal peripheral arterial pressure?

at least 65 mmHg

what is the minimum amount of peripheral arterial pressure needed for cerebral perfusion?

-evaluating unstable BP

-frequent blood draws/gases

-monitoring vasoactive meds that require titration

what is an intra-arterial catheter (peripheral arterial line) used for?

NEVER used for infusions

what is an intra-arterial catheter (peripheral arterial line) NEVER used for?

radial artery = most common site

what is the most common site for an intra-arterial catheter (peripheral arterial line)?

must do an allen's test to assess site perfusion first

what must be done before an intra-arterial catheter (peripheral arterial line) is placed?

positive allen's test = good thing (adequate perfusion)

does a positive or negative allen's test indicate that an intra-arterial catheter (peripheral arterial line) can be placed?

1. apply pressure to radial & ulnar arteries simultaneously

2. ask patient to open & close hand repeatedly --> hand should blanch

3. release pressure on ulnar artery while maintaining pressure on radial artery

4. pinkness does not return within 6 seconds, ulnar artery not adequate --> use radial artery for line insertion (this is a negative allen's test)

describe the steps of the allen's test for an intra-arterial catheter (peripheral arterial line)?

-pressure bag

-high-pressure tubing

-flush system

-transducer

-catheter

-bedside monitor

what are the components of a hemodynamic monitoring system?

1. leveling (equal w/ phlebostatic axis)

2. zeroing

3. square wave test

what 3 things are involved in a nurse ensuring accuracy in hemodynamic monitoring?

4th intercostal space mid-axillary line (location of right atrium)

where is the phlebostatic axis on a patient?

leveled/even with phlebostatic axis

regarding the transducer of a hemodynamic monitoring system, where should this be positioned?

false low-pressure readings

if the transducer is higher than the phlebostatic axis, what might this show on the monitor?

false high-pressure readings

if the transducer is lower than the phlebostatic axis, what might this show on the monitor?

transducer must be reassessed & adjusted every time patient is moved!

what is an important nursing care point to check on every time a patient is hooked up to hemodynamic monitoring?

take manual BP to compare (within 10mmHg on same arm) --> check 1x every 4 hrs then remove cuff!

in order to ensure accuracy regarding leveling the patient on hemodynamic monitoring, what should the nurse do?

confirms that when pressure within system is zero, the monitor reads 0

why is important for the nurse to zero a transducer once per shift?

-q 8-12 hours

-after blood draws

-if questioning the accuracy

when is the square wave test done in someone with hemodynamic monitoring?

tests if system is accurately transmitting pressure detected in the vessel

what does the square wave test test?

1 to 2 oscillations below baseline

what is considered a "normal" square wave test?

300 mmHg

a constant flow of sterile saline at what pressure is essential to maintain patency and avoid clot formation in an arterial line?

leveling should be repeated every position, pole, or bed change

in hemodynamic monitoring, what should be repeated with every position, pole, or bed change?

-bleeding (PRIORITY)

-infection

-air embolism

in hemodynamic monitoring, connections must be secured to withstand pressure and avoid what potential complication?

gloves and goggles

what kind of PPE should be worn by a nurse when sampling blood from an invasive line?

1. hold pressure firmly & continuously for 5 minutes BEYOND point of hemostasis

2. check site & distal circulation every 5 minutes

3. reapply pressure if oozing is observed

describe the process of removing an arterial line

every 72-96 hours

how often should lines be changed in a hemodynamic monitoring system?

(least)

-nasal canula, high flow nasal canula

-simple mask, venturi mask, non-rebreather

-blender, CPAP, BIPAP

-mechanical ventilator

(most)

what are the respiratory devices from least invasive to most invasive?

continuous positive airway pressure (CPAP)

form of noninvasive positive pressure ventilation consisting of a mask and a means of blowing oxygen or air into the mask to prevent airway collapse or to help alleviate difficulty breathing

CPAP = ↑ WOB bc patient must forcibly exhale against CPAP

how does CPAP affect work of breathing?

bilevel positive airway pressure (BiPAP)

noninvasive spontaneous breath mode of mechanical ventilation that provides 2 levels of positive pressure support, including higher inspiratory positive airway pressure and lower expiratory positive airway pressure

endotracheal (ET) intubation

placing tube through mouth and into trachea to maintain open airway and facilitate artificial ventilation

blender/AIRVO

type of high flow nasal oxygen (HFNO) used for patients who can breathe spontaneously; can provide up to 100% O2 in nasal canula form

mechanical ventilation

an invasive form of respiratory support that is used often in the critical care setting; settings can be changed to help correct ABGs, metabolic needs, and give the body rest

assist control (AC)

type of ventilator mode that has a fixed minimum rate; every breath is a mandatory breath even though the patient can trigger the breath at a more rapid rate than the set machine rate; "life support mode"

synchronized intermittent mandatory ventilation (SIMV)

type of ventilator mode that enables partial mechanical assistance; will provide a set number of breaths at a fixed tidal volume, but a patient can trigger a spontaneous breath with the volume determined by patient effort; "weaning mode"

based on patient's status (ex: ABGs, current physiologic state, level of consciousness, respiratory muscle strength, etc. )

ventilator settings are determined based on what?

tidal volume (VT)

ventilator setting that represents the volume of gas delivered to the patient during each ventilator breath

400-600 ml

what is a normal tidal volume for an adult?

FiO2

ventilator setting that represents the concentration of oxygen in the air we breathe

21%

what is the FiO2 when a patient is on room air?

PEEP (positive end expiratory pressure)

ventilator setting that represents positive pressure applied at the end of expiration of ventilator breaths

pressure support/PIP

ventilator setting that represents positive pressure used to augment patient's inspiratory pressure; max pressure during inspiration

5-10 cm of H20 pressure

what level of pressure support is usually used on a ventilated patient?

Ve (minute ventilation)

the amount of air moved in or out of lungs per minute, represents tidal volume and respiratory rate

Pplat (plateau pressure)

the pressure applied to small airways and alveoli before inspiration during positive-pressure mechanical ventilation

lung compliance

what does Pplat (plateau pressure) indicate?

-low tidal volume

-loss of connection

-cuff leak

-tube displaced

what are some potential causes of a low pressure alarm when a patient is ventilated?

-high peak pressure

-high blockage

-biting tube

-coughing

-↑ secretions/mucous plug

-pulmonary edema

what are some potential causes of a high pressure alarm when a patient is ventilated?

-always suction on OUT (never on way down)

-suction < 10 seconds

-give 100% of O2 30 seconds before

-avoid suctioning before ABG draw

-suction if high/low pressure alarms (avoid routine)

what are some points that a nurse should remember when going to suction a ventilated patient?

1. propofol

2. fentanyl

3. precedex

4. versed

what are the 4 most common medications used to sedate patients on ventilators?

weaning

the process of reducing ventilator support and resuming spontaneous breathing

-labored breathing

-dysrhythmias

-↑ HR

-restlessness/confusion

-abnormal ABGs

-use of accessory muscles

-↓ O2 sats

if a patient is intolerant to weaning, what are some clinical manifestations that might be evident?

-daily sedation vacation

-HOB 30-45 degrees

-oral care w/ chlorohexidine q2h

-hand hygiene

-q2h turns

what is involved in daily cares for intubated patients?

ventilator-associated pneumonia (VAP)

a health care-acquired infection (HAI) that develops in a person requiring invasive mechanical ventilation (via endotracheal intubation or tracheotomy tube)

1. HOB elevation

2. oral care w/ chlorhexidine

3. sedation vacations

4. daily extubation assessment

5. DVT prophylaxis

6. stress ulcer & pressure ulcer prophylaxis

what 6 things are included in the ventilator-associated pneumonia (VAP) "care bundle"?

richmond agitation-sedation scale (RASS)

a scale that can be used to monitor sedation/cognitive status while a patient is on mechanical ventilation

should be between -3 and -2

when a patient is on mechanical ventilation, where do we want their RASS score to be at?

-restraints= control unwanted behavior, such as self-extubation or accidental pulling on lines

-sedation = help alleviate pain felt on a ventilator

why might restraints and sedation be used with someone on the ventilator?

prevent a ↓ in arterial O2 saturation during suctioning procedure

why do we hyper-oxygenate a patient prior to ET suctioning?