A teaching hospital of
Harvard Medical School
Enhancing Thinking & Learning
via Mechanism Maps
Richard M. Schwartzstein, MD
David H. Roberts, MD
Shapiro Institute for Education and Research
Beth Israel Deaconess Medical Center
HMS Academy
Education is at the heart of patient care.
After this session, you will be able:
• To describe the underlying cognitive theory
behind the use of concept maps and mechanism
maps
• To use mechanism maps to foster linkage of basic
and clinical science concepts
• To enhance teaching of analytical reasoning in the
approach to clinical problems
A teaching hospital of
Harvard Medical School
How do we facilitate deep learning?
Modified from Harasym et al. 2008
Surface Learning
-- New info not linked to
previous knowledge
-- Knowledge abundant but
disorganized
-- Focus on memorization
and recall
-- Learn concepts and facts
without reflection
Deep Learning
-- Relates new knowledge to
previous knowledge
-- Content organized into
coherent whole
-- Focus on problem-solving;
synthesis, application, transfer
-- Link concepts/principles to
everyday experience
A teaching hospital of
Harvard Medical School
Encoding and Retrieval of Information
Influences Learning
Karpicke and Blunt, Science Express, 2011
• “Activities that promote effective encoding,
known as elaborative study tasks, are important
for learning”
• “Because each act of retrieval changes memory,
the act of reconstructing knowledge must be
considered essential to the process of learning”
A teaching hospital of
Harvard Medical School
Problem Solving and Neural Networks
Adapted from Jung-Beeman et al., PLoS Biology, 2004
Problem solving relies on cortical networks for
access to and use of information
Problems without obvious/immediate solutions
require engagement of distinct neural and
cognitive processes
These processes allow solvers to see connections
that may have previously eluded them
A teaching hospital of
Harvard Medical School
Encourage inductive reasoning to
enhance thinking
Modified from Pottier et al. Med Ed 2010
Inductive Reasoning
Deductive Reasoning
A teaching hospital of
Harvard Medical School
What do
Concept Maps
incorporate?
A teaching hospital of
Harvard Medical School
Mechanistic Mapping
“The mechanistic case diagram is a student
constructed tool whose objective is to trace, in
stepwise form, the pathophysiologic mechanisms
leading from underlying causes of disease
(including genetic, microbiologic, and social) to
the clinical signs and symptoms and psychosocial
consequences described in a PBL case.”
Guerrero APS, Acad. Med. 2001;76:385–389
A teaching hospital of
Harvard Medical School
…and now, let’s try one!
A teaching hospital of
Harvard Medical School
Chief Complaint
PJ is a 51 year old woman with a one year history of
intermittent abdominal pain who now presents with
nausea, vomiting, and worsening abdominal pain.
A teaching hospital of
Harvard Medical School
History
PMH
- Type II Diabetes
- Hypertension
- Rheumatoid Arthritis
- Obesity
- NO history of gallstones,
hypertriglyceridemia or prior
pancreatitis
PSH
- Low-transverse abdominal scar
c/w possible gynecologic
surgery
Medications
- Hydroclorothiazide
- Metoprolol
- Amlodipine
- Cyclobenzaprine
- Nabumetone
- Fluticasone
FH
- HTN
- No FH GI malignancy/disease
SH
- Tob: 1ppd, duration uncertain
- EtOH: 2-3 beers/day
- Illicits: unknown
A teaching hospital of
Harvard Medical School
Initial Presentation
• Vital signs notable for tachycardia to 110’s
What does this tell you? Is it specific? Sensitive?
– Increased sympathetic activity
•
•
•
•
Compensatory (hypovolemia)
Pathologic (Axis dysregulation)
Parallel (Pain)
Pharmacologic
– Decreased parasympathetic activity
• Neurologic dysregulation
• Pharmacologic
A teaching hospital of
Harvard Medical School
Initial Presentation Continued
• CT abdomen revealed acute pancreatitis
– extensive peripancreatic inflamation
– distended GB with no evidence of stones,
– diverticulosis
• RUQ ultrasound
– No stones or biliary duct dilation.
• Amylase 183
• Lipase
157
• She was admitted to their medical service, made NPO,
and started on IV fluids for presumed mild pancreatitis
A teaching hospital of
Harvard Medical School
Deterioration at Outside Hospital
• Overnight, developed hypotension, acidemia,
hyperglycemia, and extreme fever/hyperthermia
• Transferred to the OSH ICU for mechanical
ventilation, central line placement, vasopressor
support, and insulin and bicarbonate drips
A teaching hospital of
Harvard Medical School
Was her Tachycardia an early Warning Sign?
Stages of Intravascular Volume Depletion
Stage % Vol down Compensation
BP
UOP
1
2
3
4
Normal
Decreased
Decreased
Absent
<15
15-30
30-40
40+
Increase SVR
Increase HR, SVR
Increase HR, SVR
Increase HR, SVR
Normal
Normal
<100
<70
Adapted from Lawrence, Essentials of General Surgery and
The American College of Surgeons ATLS guidelines
A teaching hospital of
Harvard Medical School
Labs Prior to Transfer
125
94
15
10
2.8
550
38
(0.3)
Calcium: 5.5
Phos: 2.0
(8.4-10.3)
Mag: 4.7
(1.6-2.6)
ABG pH 6.97 pCO2 55 pO2 121
AST 126
LDH 469
ALT 63
Alb 2.9
Amylase 783 (from 183)
CK
1090
Alk Phos 95
INR 1.2
Lipase 2000 ( from 157)
Lactate 9.2
A teaching hospital of
Harvard Medical School
Condition on Arrival to BIDMC
VS: T: 106.9 HR: 152 BP: 113/61 RR: 21 O2Sat: 93% Glucose 235
• On Norepinephrine, bicarb and insulin drips
• On Ventilator (FiO2 100% RR 24 VT 400 PEEP 10)
ABG: pH 7.06
pCO2 90
pO2 121
(from 6.97)
(from 55)
(stable)
Na
145
Cl
110
HCO3 22
Exam notable for:
• ET tube properly positioned with bilateral breath sounds.
• Abdomen firm, distended, and dull to percussion.
• Extremities cool. No edema.
A teaching hospital of
Harvard Medical School
Admission CXR
ABG Trend
23:39 pH 7.06 pCO2 90 pO2 121
(FiO2 100% RR 24 Vt 400 PEEP 10)
00:19 pH 7.09 pCO2 95 pO2 106
(FiO2 100% RR 27 Vt 300 PEEP 10)
Bladder pressure 1828
A teaching hospital of
Harvard Medical School
What’s going on Here?
Problem List:
1. Hypotension
2. Hypoxemic, hypercarbic respiratory failure
3. Anion gap metabolic acidosis with overlying
respiratory acidosis
4. Pancreatitis
5. Acute Renal Failure…
A teaching hospital of
Harvard Medical School
Concept Map
Inflammatory Response,
Cytokine Release
Decreased Chest-Wall
Compliance
Pancreatitis
Increased vasculature
permeability
Increased abdominal
pressures
Hypotensio
n
Poor tissue
perfusion
Third Spacing
Anaerobic
Metabolism
A teaching hospital of
Harvard Medical School
Hypercarbic
Resp
Failure
Acidosis
Why develop Shock in Pancreatitis?
Hypovolemic Component:
– intravascular volume decreases by 19% in 2 hours
– Decreases by 30% in 6 hours
– Patients may require 10L fluid in initial 24 hours
Cardiogenic Component:
– Initially, CI increases and SVR decreases (sepsis-like)
– Later, cardiac function decreases
Distributive Component:
– Inflammatory cytokines(IL-1, IL-6, TNFalpha)  reduced SVR
Yegneswaran et. al, Cardiovascular Manifestations of Acute Pancreatitis.
J Crit Care 2011 Apr;26(2):225
Early volume-resuscitation lowers mortality
Gardner et al. Faster rate of initial fluid resuscitation in severe acute pancreatitis
diminishes in-hospital mortality. Pancreatology 2009;9:770-76
A teaching hospital of
Harvard Medical School