function Usually systemic vascular resistance (SVR) is increased. Preferred Pressors:[r]
(1)VASOPRESSOR REVIEW
Presented by: Christopher Allison, MD Resident Physician
(2)OUTLINE
• Why is my patient in shock?
• How I know when I have given enough fluids?
• What medications can I use to raise blood pressure? • What is my goal when starting a pressor?
(3)SHOCK IS THE INADEQUATE DELIVERY (AND UTILIZATION) OF OXYGEN AND NUTRIENTS TO TISSUES
Not all hypotensive patients are in shock.
(4)MARKERS OF SHOCK
Reduced urine output Altered mental status
Elevated lactate
Elevated liver enzymes Low blood pressure
Delayed capillary refill
(5)WHY IS MY PATIENT IN SHOCK?
Hypovolemic
Distributive (reduced vascular tone) Obstructive
Cardiogenic Hemorrhage Inadequate intake Diarrhea/vomiting Fistula output Sepsis Anaphylaxis Neurogenic Myocardial infarction Acidosis / Electrolytes Toxins
(6)THE “BIG TOE” TEST
Lars Plougmann
Fast Refill
Distributive shock
Slow Refill
Not distributive shock
(7)BEDSIDE ULTRASOUND THE “RUSH” EXAM
Weingart et al, Emcrit.org
Right ventricle
Left ventricle
Ultrasoundoftheweek.com
sonomojo.org Ultrasound-cases.blogspot.com Critical Care Research and Practice
(8)DOES MY PATIENT NEED MORE FLUID?
Too little fluid: Too much fluid:
Crit Care Med 2011;39:259–265
(9)VOLUME RESPONSIVENESS
(10)ASSESSING VOLUME RESPONSIVENESS
Do not use central venous pressure!
Monnet et al, Ann Intensive Care 2016; 6: 111
Passive Leg Raise
A temporary 300-500ml fluid bolus Maximum effect in about minute
Other strategies exist:
Stroke volume variation End expiratory occlusion Mini fluid challenge
When studied, volume responsiveness is measured by change in cardiac
output, not blood pressure
(11)PRESSOR PHYSIOLOGY: THE RECEPTORS
⍺1 β1 β2 Dopamine
receptor
vasoconstriction Inotropy
(stronger heart contractions) Chronotropy (faster heart rate)
Inotropy
Bronchodilation
Sodium excretion
Gut vasodilation
(12)PRESSORS: ADRENERGIC AGENTS
⍺1 β1 β2 Dopamine
receptors epinephrine norepinephrine phenylephrine dopamine dobutamine isopreterenol ++ ++++ +++ ++++ ++ + ++++
high doses medium doses low doses
+ ++++ ++
++++ +++
(13)PRESSOR PHYSIOLOGY: OTHER TARGETS
Vasopressin
receptors Troponin C,ATP-dependent
K+ channels cAMP phosphodiesterase-3 (PDE-3) vasoconstriction Anti-diuresis Calcium sensitization Inotropy and vasodilation
Inhibition leads to increased inotropy and vasodilation
Senz and Nunnink Emerg Med Australas 2009 Oct;21(5):342-51
Levosimenden Milrinone
(14)SEPTIC SHOCK
Primary Problems:
Decreased systemic
vascular resistance (SVR) Depressed myocardial function
Preferred Pressors:
Norepinephrine Vasopressin Dopamine
Norepinephrine in meta-analysis of randomized controlled trials has slightly improved mortality, fewer arrhythmias vs dopamine J Intensive Care Med 2012 May-Jun;27(3):172-8
No difference in outcomes between first-line use of vasopressin vs norephrine in septic shock NEJM 2012 May-Jun;27(3):172-8
(15)CARDIOGENIC SHOCK
Primary Problems:
Depressed myocardial
function Usually systemic vascular resistance (SVR) is increased
Preferred Pressors:
Dobutamine Milrinone
Depends on the specific scenario Cardiac output response to
treatment must be followed closely No evidence for best first choice
Dopamine Norepinephrine
High SVR, hypertension Low SVR, hypotension
Will often lower blood pressure
(16)OBSTRUCTIVE SHOCK (PULMONARY EMBOLISM)
Primary Problems:
Myocardial contractility inadequate to overcome obstruction
Preferred Pressors:
Norepinephrine or epinephrine
Increase MAP to maintain right ventricle perfusion; increase inotropy
Animal and small human studies show improved RV oxygen delivery with norepinephrine
At Maine Medical Center, we usually use norepinephrine first; though some use epinephrine.
You fix the tension pneumothorax and the tamponade with a procedure, not pressors
Right ventricular RV failure Hypotension
(17)NEUROGENIC SHOCK (SPINAL CORD INJURY)
Primary Problems:
Disrupted sympathetic nervous system signaling leads to decreased systemic vascular resistance (SVR)
A higher spinal cord lesion will sometimes cause bradycardia
Preferred Pressors:
Phenylephrine if not bradycardic J Spinal Cord Med 2008; 31(4): 403–479
Norepinephrine is a reasonable first line choice, especially if bradycardic
(18)DOES MY PATIENT NEED A CENTRAL VENOUS CATHETER?
Systematic review of mostly case series with 204 extravasation events:
85.3% of adverse events were in IVs distal to antecubital or popliteal fossae.
96.8% of adverse events occurred after hours
J Intensive Care Med 2017 Jan 1:885066616686035
A retrospective study at one institution with a protocol for peripheral IV infused pressors showed:
4% rate of extravasation (8 of 485 subjects) Median time to extravasation = 21 hours
No serious injuries requiring surgery or antidote
J Crit Care 2015; 30 (3): 653.e9 – 653.e17
Conclusion:
We believe pressors given through a peripheral IV are safe if:
- Given through a secure IV,
preferably at or proximal to the antecubital fossae
- The IV site is monitored frequently
(19)