Senior Med Surg Exam 1

Acute Respiratory Failure

The inability of the lungs to maintain adequate oxygenation of the blood with or without carbon dioxide retention

-main factor is impairment of gas exchange

Primary Hypoxemic Respiratory Failure

A type of ARF:

PaO2 < 60 mm Hg

Oxygen saturations < 90%

Can be treated with oxygen

Combination of Hypercarbia & Hypoxemia

A type of ARF:

Hypoxemia is present and an elevated

PaCO2 (PaCO2 > 50 mm Hg)

Hypercapnea : insufficient CO2 removal

Requires mechanical ventilation

hypoxemia

A low oxygen content of arterial blood, short of anoxia

Low PaO2

hypoxia

Inadequate oxygenation of the tissue

Hypercarbia

High carbon dioxide in the blood

acidemia

Too much acid in the blood

alkalemia

too much base

resp acidosis

CO2 levels going high mean what?

resp alkalosis

Low Co2 means what?

base, buffer

bicarb =

acid

CO2 = what?

acidotic, alkalotic

Normal pH is 7.35-7.45, less is ____ and more is ____

Normal PaCO2 is 35-45 mmHg

Normal PaCO2  is what?

Normal PaO2 is 80-100 mmHg

Normal PaO2  is what?

Normal HCO3 is 22-26 mEq/ L

Normal HCO3 is what?

Normal SaO2 is 95%-100%

Normal SaO2 is what?

below 6.8 or above 7.8

A pH above or below what numbers will cause the patient to die?

Inversely:

-Increase the ventilation- decrease the PaCO2

-Decrease the ventilation-increase the PaCO2

How is the value of PaCO2 related to the rate of alveolar ventilation? 

kidneys

HCO3 is bicarb, regulated by what organ?

metabolic acidosis

What does bicarb (HCO3) below 22 mean?

metabolic alkalosis

What does bicarb (HCO3) above 26 mean?

increasing the respiratory rate and the volume.

lIf the PaCO2 is elevated, the body can adjust the level of PaCO2 in a matter of minutes by doing what?

Hypoxemia, Hypoxemia & Hypercapnia

V/Q mismatch Impaired Gas diffusion

V/Q mismatch Impaired gas diffusion hypoventilation

shunt

Blood flow that reaches the arterial system without coming into contact with ventilated alveoli

Alveolar Hypoventilation

Hypercapnia

-Reducing ventilation by ½ causes a doubling of the PaCO2

Hypoxemia

Dyspnea, tachypnea, cyanosis

Signs & Symptoms of ARF

maintain adequate oxygenation and ventilation

What’s the goal of managing ARF?

Oxygen therapy: cannula, face mask, partial non-rebreather, non-rebreather, facial CP High flow nasal cannula

Secretion mobilization cough/positioning hydration/humidification chest percussion therapy suctioning

Positive pressure ventilation: Noninvasive or mechanical ventilation, Use of PEEP

What is the treatment for ARF?

Abnormal ABG’s

Body Weight

Level of Muscle Strength

What are the indications for mechanical ventilation?

ARDS

Clinical syndrome of acute hypoxemic respiratory failure due to acute lung inflammation and diffuse alveolar-capillary membrane disruption. No cardiac pulmonary edema

O2 sats doesn’t improve with supplemental oxygen

What’s the Hallmark sign of ARDS?

ARDS

Pt will look grey

Clinical features usually appear 6-72 hours after initial insult and patient declines rapidly.

CT scan – reveals widespread patchy of coalescent airspace opacities that are usually more apparent in dependent lung zones.

Positive

_____ pressure ventilators require a closed airway system between the patient and the ventilator (endotracheal tube, tracheostomy tube or sealed mask unit)

Negative

______ pressure ventilators require patients spontaneous airway and ability to protect airway

Continuous Mandatory Ventilation - CMV

Controlled rate of ventilation with preset timing, the patients respiratory efforts are ignored.

Assist Control (AC)

A base line rate of breathing  with every breath (either machine or patient initiated) get the same volume of air. 

Synchronized Intermittent Mandatory Ventilation (SIMV)

The ventilator provides a preset mechanical breath every specified number of seconds. If the patient takes a breath within that cycle the ventilator will give the ordered breath, but if the patient takes a second breath in that cycle, that breath will not be assisted

CABG indications

Multi-vessel CAD, left main disease, symptomatic refractory angina, failed PCI, or ischemia with poor LV function.

post-op CABG care

Hemodynamic monitoring (CO, PA pressures if PA cath), chest tube management (monitor drainage, preventing tamponade), ventilator/oxygen support, pain control, sternal incision care, glucose control, early extubation if possible, DVT prophylaxis, pulmonary toilet, monitor for dysrhythmias (a-fib common), renal function, electrolytes.

give IV fluids (bolus) if hypovolemic to improve stroke volume (monitor for pulmonary edema).

What do you do for Low preload?

diuretics, venodilators (e.g., nitroglycerin) to reduce congestion.

What do you do for high preload?

treat with vasodilators (e.g., nitroprusside, ACE inhibitors); reduces LV workload.

What do you do for high afterload

inotropes (dobutamine, milrinone) to improve contractility

treat cause (revascularize if ischemia).

What do you do for Low CO/CI?

Intra-aortic balloon pump (IABP)

Temporary mechanical support to increase coronary perfusion and decrease afterload in cardiogenic shock, unstable angina, or as bridge to revascularization.

Intra-aortic balloon pump (IABP)

↑ coronary blood flow

↓ myocardial oxygen demand

may improve CO temporarily.

Intra-aortic balloon pump (IABP)

• Inflates during diastole → ↑diastolic pressure → ↑coronary perfusion.

• Deflates just before systole → ↓afterload → ↓LV work and ↑forward stroke volume.

Pacemaker and ICD teaching

• Incision care: keep dry for X–48 hours (follow hospital policy), watch for redness, drainage, fever.

• Carry device ID card; know device type and follow-up schedule.

• Avoid heavy lifting (>10 lb) or raising arm above shoulder for specified weeks (typical 4–6 wks).

• Expect possible sensing/pacing sensations; after an ICD shock — call provider or go to ED depending on symptoms and device advice; document date/time of shock.

• Electromagnetic interference: most household items are safe; avoid high-output welders, MRI unless device MRI-conditional, follow provider guidance.

failure to capture — urgent.

Pacemaker spike w/no QRS = ?

care and monitoring for ICD

• Similar wound care to pacemaker, device interrogation, educate patient about what a shock feels like and when to seek help.

• Driving restrictions after ICD shock vary by jurisdiction; ensure patient knows local rules.

• Avoid direct trauma to device, inform airport security and give ID card. MRI compatibility depends on device.

indication for Implantable Cardioverter-Defibrillator (ICD)

Secondary prevention after survived sudden cardiac arrest/VT, primary prevention in high risk patients (severe LV dysfunction), sustained VT.

ventricular pacing with capture.

Pacemaker rhythm strips:

Spike before every QRS with consistent QRS →

failure to capture (urgent)

Pacemaker rhythm strips:

• Spike without QRS →

failure to pace/sense problem.

Pacemaker rhythm strips:

• No spikes when expected and bradycardia →

atrial, ventricular, dual

before P wave (____), before QRS (______), or both (____).

ARF

O2 <60 on room air

pacos

ph <7.35

Assist-Control (A/C)

Mode of mechanical ventilation: every patient or assisted breath is full preset tidal volume — risk of hyperventilation if patient tachypneic.

SIMV (Synchronized Intermittent Mandatory Ventilation):

Mode of mechanical ventilation: set mandatory breaths synchronized; patient may take spontaneous breaths at their own tidal volume.

Pressure Support Ventilation (PSV):

Mode of mechanical ventilation: patient-triggered breaths supported by set pressure — used for weaning.

PRVC (pressure regulated volume control)/VC:

Mode of mechanical ventilation: hybrid modes exist.

control mode

Mode of mechanical ventilation: for paralyzed patients.

Mechanical ventilation settings

• Tidal volume (Vt): 6 mL/kg predicted body weight (lung protective; sometimes 4–8 mL/kg).

• RR: to achieve target PaCO₂.

• FiO₂: start high to maintain SpO₂ then titrate down (<60% if possible).

• PEEP: improves oxygenation, but watch for decreased venous return/hypotension.

• I:E ratio & inspiratory flow.

• Alarms: high pressure, low volume, apnea — set appropriately.

Hypoxemic respiratory failure

Low PaO₂ (<60), PaCO₂ normal or low (if hyperventilating), pH variable.

Hypercapnic respiratory failure

High PaCO₂ (>50), pH ↓ (resp acidosis), PaO₂ often low.

ARDS

Severe, acute inflammatory lung injury → non-cardiogenic pulmonary edema, ↓lung compliance, shunt physiology

severe hypoxemia (low PaO₂), low P/F ratio, often normal/low PaCO₂ early, but may rise if ventilatory failure.

indications for intubation

Failure to maintain airway/oxygenation (PaO₂ <60 on maximal O₂)

severe respiratory acidosis (pH <7.25)

exhaustion, inability to protect airway

severe hypoxia,

need for airway control during procedures.

pH

7.35–7.45

PaCO₂:

35–45 mmHg (respiratory component)

HCO₃

22–26 mEq/L (metabolic component)

PaO₂:

80–100 mmHg (on RA)

SaO₂

>94%

Respiratory acidosis:

PaCO₂, ↓pH → hypoventilation (opioids, COPD exacerbation, respiratory muscle fatigue).

Respiratory alkalosis

↓PaCO₂, ↑pH → hyperventilation (anxiety, pain, early PE).

Metabolic acidosis:

↓HCO₃⁻, ↓pH → DKA, sepsis; compensation: ↓PaCO₂.

Metabolic alkalosis

↑HCO₃⁻, ↑pH → vomiting, diuretics; compensation: ↑PaCO₂.

CPAP (continuous positive airway pressure):

Single pressure (keeps alveoli open) — helpful in cardiogenic pulmonary edema, OSA.

BiPAP (BPAP / bilevel):

inspiratory positive airway pressure (IPAP) and expiratory (EPAP) — assists ventilation (reduces PaCO₂) and oxygenation.

• Endotracheal intubation + mechanical ventilator (volume or pressure modes).

• Tracheostomy (long-term airway).

What are the types of invasive ventilatory assistance?

Why do we do hemodynamic monitoring?

To set zero reference point and ensure transducer reads true pressures relative to the patient’s heart.

Level transducer

Zeroing

___________ at the phlebostatic axis (4th intercostal space at mid-axillary line) — represents the right atrium reference.

________: open transducer to air (atmospheric) and zero prior to use and after repositioning or system changes.

What are some indications for a pacemaker? 

Symptomatic bradycardia, sinus node dysfunction, high-grade AV block, tachyarrhythmia therapies (some devices), sometimes for cardiac resynchronization therapy (biventricular pacing).

• Temporary

• Permanent

• _______: transcutaneous, transvenous, epicardial (ICU/post-op).

• _______: implanted generator with leads (single or dual chamber, biventricular).