10/9/2017

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Leanna R. Miller, DNP, RN, CCRN-CMC, PCCN-CSC, CEN, CNRN, CMSRN, NP

Education Specialist

LRM Consulting

Nashville, TN

NO DISCLOSURES

Objectives

Identify the 5 criteria for the diagnosis of ARDS.

Discuss the common etiologies that lead to ARDS.

Describe the priorities in the management of patients with ARDS.

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diffuse lung injury resulting in

noncardiogenic pulmonary

edema due to increase in

capillary permeability

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• refractory hypoxemia

• diminished compliance

• diffuse infiltrates on chest x-ray

• normal PAOP

• PaO2 / FiO2 ratio < 200

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• Etiology

–shock

– trauma

– infections

– inhaled toxins

• Etiology

– aspiration

– near-drowning

– massive blood transfusions

– fat or amniotic fluid emboli

– pancreatitis

• Phase I & II

–subclinical respiratory distress

–ABGs (respiratory alkalosis)

–hyperventilating

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• Phase III

– established respiratory distress

– pulmonary shunt > 10% above baseline

– chest x-ray shows infiltrates

– crackles in lung bases

• Phase IV

–severe respiratory failure

– rising pCO2

– rising physiologic shunt

–white-out on chest x-ray

• Diagnosis

–history

–signs/symptoms

– labs (ABGs)

–x-ray

–hemodynamics

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• Treatment

–establish patent

airway

– restore arterial O2

level

• Mechanical Ventilation

– conventional with PEEP

–PC / IRV

–HFJV

–APRV

• Goals of mechanical ventilation in

ARDS are to:

–maintain oxygenation

– avoiding oxygen toxicity and the

complications of mechanical

ventilation

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• maintain oxygen saturation in the range of

85-90%

• aim of reducing the fraction of inspired

oxygen (FIO2) to less than 60% within the

first 24-48 hours

• usually requires the use of moderate-to-high

levels of PEEP

• experimental studies have shown that

mechanical ventilation may promote a type

of acute lung injury (ALI) termed ventilator-

associated lung injury

• protective ventilation strategies using low

tidal volumes and limited plateau pressures

improves survival when compared with

conventional tidal volumes and pressures

• ARDS Network study

– patients with ALI and ARDS were randomized to

mechanical ventilation

• tidal volume of 12 mL/kg of predicted body

weight and an inspiratory pressure of 50 cm

water or less

• tidal volume of 6 mL/kg and an inspiratory

pressure of 30 cm water or less

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• the study was stopped early after interim

analysis of 861 patients demonstrated that

subjects in the low-tidal-volume group had

a significantly lower mortality rate (31%

versus 39.8%)

• mechanical ventilation with a tidal

volume of 6 mL/kg predicted body

weight is recommended, with

adjustment of the tidal volume to

as low as 4 mL/kg if needed to limit

the inspiratory plateau pressure to

30 cm water or less

• increase the ventilator rate and

administer bicarbonate as needed

to maintain the pH at a near normal

level (7.3)

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• High-frequency ventilation uses low

tidal volumes and high respiratory

rates.

• diminishes alveolar distention

• compared to conventional ventilation in

adults demonstrates early improvement

in oxygenation but no improvement in

survival.

• Fluid Management

–maintain adequate perfusion

– isotonic solutions

– fluid restriction

–consider diuretics**Seeley (2013) Updates in the management

of acute lung injury: A focus on the overlap

between AKI and ARDS. Advances in

Chronic Kidney Disease, 20(1): 14-20.

• primary ARDS due to aspiration, pneumonia,

or inhalational injury treated with fluid

restriction

• secondary ARDS due to remote infection or

inflammation requires initial fluid and

potential vasoactive drug therapy

• essential in directing initial treatments to

stabilize the patient

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• Improve systemic O2Delivery

– modest volume expansion

– vasopressors/vasodilators

• Sedation

– control anxiety & physical activity

– may require addition of neuromuscular blocker

– suggestions:

• propofol

• versed

• Positioning

– “good lung” in dependent position

– both lungs are equally injured

– beneficial positions include:

• prone

• right lung down

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• 60-75% of patients with ARDS have

significantly improved oxygenation

when turned from the supine to the

prone position

• improvement in oxygenation is rapid

and often substantial enough to allow

reductions in FiO2 or level of CPAP

• Possible mechanisms for improvement

are:

– recruitment of dependent lung zones

– increased functional residual capacity (FRC)

– improved diaphragmatic excursion

– increased cardiac output

– improved ventilation-perfusion matching

• despite improved oxygenation with

the prone position, randomized

controlled trials of the prone

position in ARDS have not

demonstrated improved survival

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• Pharmacologic Therapy

– corticosteroids

– antimicrobials

– non - steroidal anti -inflammatory agents

– anti – pyretic

– “Star – Trek Meds”

• No drug has proved beneficial in the

prevention or management of acute

respiratory distress syndrome (ARDS).

• Hemoglobin

– 12 to 15 gm / dL

– factors decreasing offloading:

• hypophosphatemia

• alkalosis

• hypothermia

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• Nutritional Support

– often overlooked in ARDS

– ingredients required:

• stress amino acid

• trace elements

• omega 3 / omega 6

– Oxepa or Impact

• patients who required mechanical

ventilation within 48 hours of

developing acute lung injury

received either trophic or full

enteral feeding for the first 6 days

• Initial lower-volume trophic enteral

feeding did not improve

– ventilator-free days

– 60-day mortality

– infectious complications

– it was associated with less

gastrointestinal intolerance

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• Other Therapeutics

– nitric oxide

– surfactant

–ECMOa

– partial liquid ventilation

a Michaels, et al (2013) Adult refractory hypoxemic ARDS treated with ECMO,

American Journal of Surgery. 205(5): 492-498.

Extracorporeal Membrane Oxygenation

(ECMO)• Description

– type of cardiopulmonary

bypass

– CO2 removal; O2 replacement

– ventilated (lower VT, FiO2, &

PEEP)

Extracorporeal Membrane Oxygenation

(ECMO)

• Complications

– technical difficulties

– cannula malposition

– hemorrhage

– sepsis

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• ECMO appeared to improve survival in

patients with H1N1-associated ARDS

who could not be oxygenated with

conventional mechanical ventilation

• randomized controlled trial that

compared partial liquid with

conventional mechanical ventilation

– partial liquid ventilation resulted in

increased morbidity

• pneumothoraces

• hypotension

• hypoxemic episodes

– trend toward higher mortality

Case Study

48 - year old alcoholic with GI bleed & pancreatitis

severe epigastric pain, acute abdomen

ultrasound confirms enlarged, edematous pancreas

hemodynamically unstable

refractory hypoxemia

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Case Study

HR 130

BP 80 / 50 / 62

Case Study

HR 130

BP 80 / 50 / 62

CI 2.2

PAP 15 / 8 / 10

PAOP / CVP 2 / 1

Case Study

PVRI 290

SVRI 2218

SVI 28

LVSWI/RVSWI 22.8 / 2.6

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Case Study

ABGs (.70 FiO2)

pH 7.38

pCO2 45

pO2 50

SaO2 .83

HCO3 27

SvO2 60%

Case Study

PaO2 / FiO2 Ratio (P/F)

• 50 / .70

• 71

Normal = > 300

ALI = < 250

ARDS = < 200

Case Study

Laboratory Values

Na 150

Cl 96

Hgb / Hct 12.1 / 36.3

CO2 26

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Case Study

Anion Gap

• Na – (CO2 + Cl)

• 150 – (96 + 26)

• 28

(Normal = 12 – 15)

PEEP can DOI2 WOB VOI2 triggers inflammatory

response

maldistributed blood flow VOI2

ideal Hgb is 12

DOI2 until

VOI2 plateaus

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Case Study

DOI2 = CI ( 1.38 x Hgb x SaO2) 10

2.2 X 1.38 X 12.1 X 0.83 x 10

305 mL/min/m2

(normal = 360 - 600 mL/min/m2)

Case Study

VOI2 = CI X 1.38 X Hgb X (SaO2 - SvO2) X 10

2.2 x 1.38 x 12.1 x (.83 - .60) x 10

84 mL/min/m2

(Normal 220 - 290 mL/min/m2)

In Summary

• 6 P’s of ARDS Management

–Pathophysiology

–Prevention

–Positive Pressure Ventilation

–Perfusion

–Pharmacology

–Positioning

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