ASSESSMENT OF THE PATIENT WITH A LOW BLOOD PRESSURE

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ASSESSMENT OF THE PATIENT WITH A LOW BLOOD
PRESSURE

• Peter E. Morris, MD, FACP, FCCP
• Pulmonary Critical Care Medicine
• Wake Forest University School of Medicine
• Winston Salem, NC

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ASSESSMENT OF THE PATIENT WITH A LOW BLOOD
PRESSURE
What is an abnormal blood pressure? HYPOVOLEMIA H
YPOTENSION SHOCK ADEQUATE PERFUSION
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BLOOD PRESSURE GOAL MAP vs Systolic? MAP 60-70
mmHg Systolic gt90
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CEREBRAL PERFUSION PRESSURE (CPP)
MAP-ICP CPP

• 65-5 60 mmHG
• lt60 ? risk of brain ischemia
• and neuronal damage

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Relative CBF
Normal
Hypertensive
(Autoregulation)
50
100
150
200
MAP
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SHOCK

• Cardiogenic
• Neurologic
• Distributive
• Hypovolemic

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SHOCK

• Preshock known as warm shock or compensated
  shock
• homeostatic mechanisms rapidly compensate for
  diminished perfusion
• Despite a 10 percent reduction in total effective
  blood volume, a previously healthy adult may be
  asymptomatic
• Tachycardia, peripheral vasoconstriction, modest
  decrement in systemic blood pressure

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SHOCK

• Shock During this stage, regulatory mechanisms
  are overwhelmed - signs and symptoms of organ
  dysfunction appear tachycardia, tachypnea,
  metabolic acidosis, oliguria, cool and clammy
  skin.
• A 20 to 25 percent reduction in effective blood
  volume

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• REASONS FOR SHOCK
• Hemorrhage
• Myocardial dysfunction (cardiomyopathy,
  ischemia, pharmacologic, toxic,
  valvular)
• Circulatory obstruction (pulmonary embolus,
  cardiac tamponade,
  pneumothorax) (contd)

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REASONS FOR SHOCK

• Hypovolemia (gastrointestinal GI, insensible
  losses)
• Central sympathetic disruption (Drug
  overdose)
• Arteriovenous fistula
• (contd)

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REASONS FOR SHOCK

• Vascular Endothelial Cell Dysfunction/Disruption
• Sepsis (bacterial, viral, fungal)
• Anaphylaxis
• Dyshemoglobinemia (carbon monoxide,
  methemoglobinemia)
• Cellular poisons (cyanide sulfur, iron, lithium)
• Traumatic or massive tissue destruction
• Heat shock, Hypothermia

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Age Variation
Compensatory reflexes may be more prominently
demonstrated in young adults. Considerable
variability exists at extremes of age Most
notably, younger individuals are able to
maintain normal blood pressure until
cardiovascular decompensation is imminent
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FOR MOST ACUTELY HYPOTENSIVE PTS
if PULMONARY EDEMA (-) then FLUID CHALLENGE
IS AN APPROPRIATE FIRST RESPONSE
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FLUID CHALLENGE? BOLUS OF FLUID?

• HOW MUCH?
• HOW FAST?
• LENGTH OF TUBING
• DIAMETER OF CATHETER
• LENGTH OF CATHETER
• PRESSURE BAGS

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A Spectrum of Severity
LOW URINE OUTPUT DEHYDRATION INTRAVASCULAR
VOLUME HYPOTENSION
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DURING RESUSCITATION REMEMBER TO MONITOR MENTAL
STATUS VITAL SIGNS (MAP - O2 SATS) URINE
OUTPUT SKIN PERFUSION (LACTATE)
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SHOCK RESUSCITATION

• Golden Rule early 1960s Parkland
  Hospital, Dallas TX First
  hour post-trauma attention to blood pressure
  improves outcome
• Traditionally, Internal Medicine-trained critical
  care practitioners
• Never heard of Golden Rule?
• Fear of Volume resuscitation? 2o Fear of CHF or
  Intubation?

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Sepsis Defining a Disease Continuum
Sepsis
Severe Sepsis
Infection

• SIRS
• Temperature ?38oC or ?36oC
• HR ?90 beats/min
• Respirations ?20/min
• WBC count ?12,000/mm3 or ?4,000/mm3 or gt10
  immature neutrophils

• Sepsis with ?1 sign of organ failure
• Cardiovascular (refractory hypotension)
• Renal
• Respiratory
• Hepatic
• Hematologic
• CNS
• Unexplained metabolic acidosis

Mechanical Ventilation
Acute Dialysis
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Early Goal-Directed Therapy for Septic Shock

• Standard
• CVP ?8-12 mm Hg
• Vasopressors for SBP ?90 mm Hg
• Maintain UOP ?0.5 mL/kg/hr
• MAP ?65 mm Hg
• Goal-directed
• Above, plus
• Patients monitored with CVP and SVO2
• If SVO2 lt70
• RBCs until Hct ?30
• If SVO2 still lt70, add dobutamine to dose of 20
  µg/kg/min

• Randomized, non-blinded trial of traditional vs
  early goal-directed therapy (EGT)
• Septic shock unresponsive to 20 mL/kg
  crystalloids, or
• Lactate ?4 mmol/L

Rivers E, et al. N Engl J Med 20013451368-77.
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O2 Delivery Uptake during Severe Sepsis

• D-O2 Cardiac Output x Hgb x O2 sat
• V-O2 Bodys uptake of oxygen
• As blood circulates from arteries capillaries
  veins oxygen content decreases
• Response to increase tissue demand (exercise,
  illness) ?cardiac output, ? O2 extraction

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O2 Delivery Uptake during Severe Sepsis

• Crude estimate of O2 extraction is
• Arterial O2 sat minus Venous O2 sat
• Normal arterial O2 sat gt 95
• Normal mixed venous O2 sat 75
• For Severe Sepsis Pt in shock
• if mixed venous O2 sat 50, suspicion that
  tissue O2 needs may not be met

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Mixed venous hemoglobin-O2 saturation (SVO2) Nl
70-75 O2 content low
Arterial Hemoglobin-O2 saturation Nl 95 O2
content high
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Flow-dependent O2 Uptake
Arterial Hemoglobin-O2 saturation Nl 95 O2
content high
Mixed venous hemoglobin-O2 saturation
(SVO2) lt70 O2 content very low
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EGT Pts Received More Fluids, RBCs and Dobutamine
Fluids in mL
Patients Receiving Treatment ()
6000
5000
4000
3000
2000
1000
0
Pressors
First 6 hours
Rivers E, et al. N Engl J Med 20013451368-77.
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Early Goal-Directed Therapy for Septic Shock

• EGT in patients with severe sepsis produced the
  following
• 42 ? in relative risk of in-hospital and 28-day
  mortality (P0.009, P0.01)
• 33 ? in relative risk of death at 60 days
  (P0.03)
• NNT to prevent 1 event (death) 6-8

Mortality ()
Aggressive resuscitation begun in emergency
department. Rivers E, et al. N Engl J Med
20013451368-77.
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Surviving Sepsis Campaign guidelines for
management of severe sepsis and septic shock

• Sponsoring Organizations American Association of
  Critical-Care Nurses, American College of Chest
  Physicians, American College of Emergency
  Physicians, American Thoracic Society, Australian
  and New Zealand Intensive Care Society, European
  Society of Clinical Microbiology and Infectious
  Diseases, European Society of Intensive Care
  Medicine, European Respiratory Society,
  International Sepsis Forum, Society of Critical
  Care Medicine, Surgical Infection Society,
• Crit Care Med 2004 32858873

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6 24 Hour Severe Sepsis BUNDLES

• 6 Hour
• Dx
• Lactate
• Antibiotics
• Fluids
• CVP
• MAPgt65
• mvO2 sat

• 24 Hour
• Glclt150
• Vent Plat Presslt30
• APC considered
• Adrenal Evaluation

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HOURLY VOLUME OF RESUSCITATION FLUID Severe
Sepsis Patients
no difference in average volume between Nov/Dec
March significant difference in average
volume between order and non-order March sepsis
patients Note t-test done on log volume
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Annane D et al. Effect of Treatment With Low
Doses of Hydrocortisone and Fludrocortisone on
Mortality in Patients With Septic ShockJAMA 2002
288 862-871
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114 pts
150 pts
115 pts
150 pts
P 0.03
Annane D et al. Effect of Treatment With Low
Doses of Hydrocortisone and Fludrocortisone on
Mortality in Patients With Septic ShockJAMA 2002
288 862-871