Wednesday Conference – August 25,2010
Moderator: Dr. Cornelio Dela Paz
Topics:
1. CAT: Sleep Tendency as a Measure of Recovery after Drugs Used for Ambulatory Surgery
–Yuan Paco
2. Trauma Joint Clinical Case Conference – Dave Arbizo
3. Trauma Joint Clinical Case Conference (Discussion) – MJ Maranan
I. Clinically Appraised Topic (CAT):
Sleep Tendency as a Measure of Recovery after Drugs Used for Ambulatory Surgery
-Yuan Paco
Today, many surgical procedures are performed in an out-patient setting, where patients
receive conscious sedation. The goal of ambulatory anesthesia, is to have a patient leave the clinic as
soon as possible after a procedure to return to normal activities. During conscious sedation for
endoscopic, cardiac, and ambulatory surgical procedures medication is administered to provide amnesia
and sedation, to reduce anxiety, and to control pain.
Problem: Determine a sedation regimen that would produce the least residual effect
PIOM:
 Population
 Patients in ambulatory setting or procedures
 Intervention
 IV anesthetics
 Propofol
 Propofol and Fentanyl
 Propofol and Midazolam
 Midazolamand Fentanyl
 Outcome
 Determine sedation regimen that produce the least residual effect
 Early discharge
 Methods
 Randomized Clinical Trial
 Was the assignment of patients to anesthetics randomized?
 Yes
 Four separate occasions, volunteers (N = 12) received injections of:
 Propofol 2.5mg/kg
 Propofol 2.0mg/kg and Fentanyl 2μg/kg
 Propofol 2.0mg/kg and Midazolam 2mg/70kg
 Midazolam 0.07mg/kg and Fentanyl 2μg/kg
 Were the groups similar at the start of the trial?
 Yes
 N = 12
 8 men, 4 women in good health
 (± SD) Mean age: 26.3 ± 4.4year
 Height: 174 ± 13cm
 Weight: 74 ± 13kg
 Aside from the allocated treatment, were groups treated equally?
 Screened by telephone
 Determine the regulatory of their sleep habits
 Candidates were excluded if they complained of
 Difficulty initiating or maintaining sleep
 Varied usual bedtime or time of rising by more than 1 hour
 Did not spend more than 7.5-8.5 hours each night in bed
 Napped during the day
 Had insomnia or narcolepsy
 Aside from the allocated treatment, were groups treated equally?
 Anesthesiologist conducted personal interview and physical examination to verify the
health status of the patients
 Laboratory work-ups
 CBC
 ECG
 Serum electrolytes
 Additional exclusion criteria
 Adverse experience with anesthesia
 Sedation
 Analgesia
 Systemic disease
 Pregnancy or possibility of pregnancy
 Volunteers admitted for screening
 Nighttime sleep patterns
 Daytime sleep latency
 Monitored with an electroencephalogram or an activity monitor
 Adequate 8 hour in bed and adequate sleep efficiency
 The following day
 Psychomotor performance
 Sleep latency
 Measured using the MSLT
 1000h, 1200h, 1400h, 1600h
 First (acclimation) period of study (Control)
 Admitted to the study
 Average sleep latency was ≥ 10min
 No onset of REM
 Narcolepsy
 Subjects must return to the laboratory on four other days
 Again monitored
 Three subjects were admitted on Sunday, 3 on Monday, 3 on Tuesday, and 3 on
Wednesday
 Always admitted on the same day of the week for each of the 4 days of drug
injection
 Aside from the allocated treatment, were groups treated equally?
 Patients were prepared for sedation
 Received one of four injections
 Were all patients who entered the trial accounted for? And were they analysed in the groups to
which they were randomised?
 Yes
 Patients received one of four injections
 Administered in random order
 Propofol 2.5mg/kg
 Propofol 2.0mg/kg and Fentanyl 2μg/kg
 Propofol 2.0mg/kg and Midazolam 2mg/70kg
 Midazolam 0.07mg/kg and Fentanyl 2μg/kg
 Were measures objective or were the patients and clinicians kept “blind” to which treatment
was being received?
 Subjects and investigators were blinded to agents administered
The Results:
 Will the results help me in caring for my patient?
 Yes
 Is my patient so different to those in the study that the results cannot apply?
 No
 Is the treatment feasible in my setting?
 Yes
 Will the potential benefits of treatment outweigh the potential harms of treatment for
my patients
 Yes
Conclusion:
 Sleep latency is a more sensitive indicator of drug effect after sedation than are tests of
psychomotor performance.
 Furthermore, propofol and propofol with fentanyldecreased sleep latency the least of the four
drug combinations tested.
End Discussion:
 Only small group of patients are included in the study; no mention of mode of administration of
used drugs
 Propofol has shorter half life than midazolam – shorter acting drugs → faster discharge; short
duration of action, good for OPD procedures
II. Trauma Joint Clinical Case Conference – Dave Arbizo
The Case:
 21 year-old male
 ASA 1 E
 Suffered from multiple stab wounds
 HPI:
 2 hours prior to admission (April 15, 2010, 3:30 am), patient was walking on the street
when he was stabbed by a known assailant.
 Was then rushed to PGH for management.
PE:
 conscious, coherent, approximately 65 kgs
 vital signs of BP: 100/60 mmHg, HR: 84 bpm, RR 20-22 bpm, afebrile
 mallampati 1, mouth opening of 3 finger breadths, adequate thyromental distance
 symmetric chest expansion, clear and equal breath sounds, no retractions, adynamic
precordium, distinct heart sounds, and no murmurs were appreciated
 Patient had fair and equal pulses
 flat, soft, tender abdomen, with normoactive bowel sounds.
 Multiple stab wounds were noted over the following areas:
 2nd ICS midsternal line left
 Anterior arm, left
 Post deltoid,R
 T1 midscapular line,R
 6th ICS, PAL, R
 T8 paravertebral line R
 L3 PAL R
 T3 paravertebral line,L
 3rd ICS PAL, L
Pre-operative course:
 put on NPO
 2 IV lines were secured
 normal hemoglobin, hematocrit, and platelet count
 slight elevation of ESR: 0.837 (0.5-0.7)
 ~ 2x elevated wbc: 27.7 (4-11)
 Cefuroxime 750 mg IV q8, Metronidazole 500 mg IV q6, Tramadol 50 mg IV q8, and
Famotidine 20 mg IV q12
 Abdominal survey showed abdominal fluid collection in the hepatorenal, splenorenal,
and pelvic regions
 Pericardial UTZ did not show abnormal free fluid collection within the pericardium at
the time of examination
 Diagnosis:
 Multiple stab wounds
 Surgical plan:
 Exploratory laparotomy
 Anesthesia Technique:
 GETA, rapid sequence induction
 transferred to OR table approximately 6 hours from admission
 at the OR:
conscious, coherent, normotensive (BP: 110/60), tachycardic (HR 110 bpm), not in respiratory
distress (16 bpm), with oxygen saturation of 99% (100% FiO2 via face mask).
Intraoperative Course:
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pre-oxygenation with 100% oxygen via face mask, then:
100 ug Fentanyl (1.5 ug/kg)
pre-treatment of 5 mg Atracurium
150 mg Propofol (2.3 mg/kg)
sellicks maneuver
100 mg Succinylcholine (1.5 mg/kg).
 intubated with ET tube size 8.0, cuffed and secured at level 20 using mac 3 blade
 equal, clear breath sounds
 maintained on Isoflurane 2-3 volume%.
 Tachycardia (HR 105-110 bpm) persisted 15 minutes from induction
 A> poor circulating volume thus hydration with pNSS was done
 Urine output during this time was approximately 20 cc.
 30 minutes from induction or 15 minutes from cutting: Persistent tachycardia
 Transfusion of 1 unit pRBC
 Transfusion was considered because 400 cc of clotted hemoperitoneum was evacuated.
 30 minutes from cutting: persistent tachycardia
 pain was considered
 50 ug of Fentanyl was given which eventually decreased the HR to 90s
 2 hours and 15 minutes from cutting, elevation in BP (130/80 mm Hg) and HR (103-105 bpm)
 A> light anesthesia
 Isoflurane was increased again to 2 volume%
 No improvement
 2 hours 30 minutes from cutting: Surgery ended and Isoflurane was turned off
 run of PVCs / ventricular tachycardia and undocumented fever
 300 mg Paracetamol IV and 100 mg of Lidocaine IV were given because the defibrillator
was not readily available during this time
 However, no improvement was seen
 Ventricular tachycardia persisted for 15 minutes, and during this time, BP and HR
decreased and eventually became 0 in span of 15 minutes (130/80  100/60  0; 95 
75  0, respectively)
 CODE was called, and ACLS was done
 Left thoracotomy and cardiac massage were done while 1 mg of epinephrine being given every 3
minutes
 Despite efforts in resuscitation, the patient was not revived and pronounced dead 30 minutes
after the arrest.
 Pronounced dead 30 minutes after resuscitation
 Post-mortem care given
 Body sent to morgue
Summary:
 Surgical Procedure:
 Exploratory laparotomy, evacuation of hematoma, cecorraphy, appendectomy, suturing
of posterior abdominal wall laceration, thoracotomy, cardiac massage
 Total OR time:
 3.5 hours (including thoracotomy)
 Estimated Blood Loss:
 500 cc
 Input:
 3750 (3000 cc crystalloids, 1 unit pRBC)
 Output:
 3787 ( 1820 cc Insensible losses, 367 cc maintenance fluid, 500 cc blood loss, 100 cc UO)
 Findings
 400 cc hemoperitoneum, 1 cm cecal injury, 2 cm laceration at the right posterior
abdominal wall, thoracotomy showed serous pericardial fluid, no pneumohemothorax,
no cardiac injury
 Cause of Death:
 Fatal Arrythmia
End Discussion:
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Wbc 27.7 (pre-op)
Tachycardic – ACLS protocol → secure at least 4units prbc for trauma patients
Undocumented Fever? – absent preop, but noted at end of surgery
Persistent tachycardia
o Pain – fentanyl 50ug →underdose; ↑ isoflurane → no resolution
DDX: malignant hyperthermia – EtCO2 should bemonitored
III. Discussion – MJ Maranan
Critical event: intraoperative arrhythmia → cardiac arrest
Analysis of the Case:
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Leukocytosis
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severe leukocytosis (27.7 x 109/L)
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white blood cell count greater than 11,000 per mm3 (11 X 109 per L).
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frequently found in the course of routine laboratory testing.
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An elevated white blood cell count typically reflects the normal response of bone
marrow to an infectious or inflammatory process.
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In trauma pxs:
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due to neutrophilia caused by catecholamine-induced neutrophil margination,
and not due to increased marrow production or release of immature cells or
bands.
•
short-lived, lasting only minutes to hours.
•
In theory, patients with significant injury should have a higher degree of
leukocytosis compared to patients with minor injuries
a non-specific measure of
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inflammation, being associated with bacterial and fungal infection
Neoplasms
trauma,
myocardial ischaemia
almost any medical condition that causes stress.
Extreme leukocytosis : >25 x 109/L
moderate leukocytosis : 12–25x109/L.
Elevated WBC can be associated with intra-abdominal injury
adult patients who had had >25 x 109 /L leukocytes at any one point during their
hospitalization had a 31% case fatality rate.
patients with WBC of >25 x109/L at admission to an adult intensive care department
had a higher case fatality than those whose WBC was 10–25x109/L
Analysis of the case
• Arrhythmia
-Anesthesia-Related
• Volatile Anesthesia and other anesthetic agents
• Light Anesthesia
• Malignant Hyperthermia
- Patient-Related
• Unelicited pre-existing medical condition (electrolyte abnormalities)
- Surgery-Related
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Abdominal surgery
Other contributing factors
Missed cardiac injury
Arrythmia: “Arrhythmias and conduction defects during surgery have been attributed to the use
of certain anesthetics or combinations of cyclopropane ,halothane, vasopressors,
parasympatholytics,’ and muscle relaxants, or to intubation ; to certain types of surgical
procedures, such as cerebral, thoracic, ophthalmologic and abdominal to hypoxia and acidosis.”
•
The most common cause of tachycardia in the perioperative period are:
• Pain
• Hypoxia
• Hypercarbia
• Hypovolemia
• sepsis
The presence of more than 5 premature ventricular contractions in one minute is said to increase the
cardiac risk in the perioperative period.
• Arrhythmias may lead to serious complications such as:
– cardiac infarction
– cerebrovascular insufficiency
– forewarn the onset of cardiac arrest
•
Anesthesia-Related
Volatile anesthetics may directly inhibit cardiac fast Na+ inward current (INa) and, consequently, may be
responsible for slowing impulse conduction and dysrhythmias due to abnormal conduction and reentry
• Arrhythmia during anesthesia
– overall incidence of ventricular arrhythmias was low, being 2.5% during induction and
2.3% during maintenance
• Preoperative ventricular arrhythmias were present in 1.9% of the population, and these patients
accounted for 33 % of all ventricular arrhythmias on induction and 35% of such arrhythmias
during the maintenance of anaesthesia.
• In patients without preoperative ventricular arrhythmias, new ventricular arrhythmias occurred
during induction at a low rate (2.2 %).
• Hypertension may also be a sign of endogenous catecholamine release associated with light
anaesthesia, and this may precipitate ventricular arrhythmias
• Pain/inadequate analgesia -Inadequate analgesia would result in the patient perceiving pain and
thus eliciting the stress response with out-pouring of adrenaline into the circulation.
• Effects of respiratory maneuver during mechanical ventilation:
- A downward shift in the cardiac pacemaker may occur during hyperventilation, from S-A
node to the atria, to the A-V node, and then A-V dissociation when a ventricular pacemaker
takes over
• - It may also cause arrhythmias by stimulating stretch receptors in the visceral pleura or
parietal parenchyma by changing intrathoracic pressure
• A vagal reflex can also be induced by alteration in blood gases- prolonged respiratory alkalosis
causes a migration of potassium across the cell membrane and increased irritability of the heart
because of the alteration of cellular membrane potentials
• Prolonged respiratory alkalosis causes a migration of potassium across the cell membrane and
increased irritability of the heart because of the alteration of cellular membrane potentials.
• Malignant Hyperthermia - It is an inherited uncommon pharmacogenetic disorder of the skeletal
muscle; involving an acute hypermetabolic state of skeletal muscle, resulting in excessive heat
and carbon dioxide production.
– Classic signs and symptoms: initial signs of tachycardia and tachypnea result from
sympathetic nervous system stimulation secondary to underlying hypermetabolism
derived primarily from the skeletal muscle
– Because many patients receive neuromuscular blockers and controlled ventilation
during general anesthesia, tachypnea is usually not recognized.
– Shortly after the increase in heart rate, an increase in BP occurs, often associated with
ventricular dysrhthmias induced by sympathetic nervous system stimulation resulting
from hypercarbia, hyperkalemia and/or catecholamine release.
– An increase in muscle tone may (or may not) become apparent. Increase in body
temperature at a rate of 1-2 degree Celsius every 5 minutes, follow (not uncommonly
higher than 40 ̊C[104 ̊F])
– patient may display peripheral mottling, sweating and cyanosis.
– Blood gas analysis reveals respiratory and/or metabolic acidosis without marked oxygen
desaturation.
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Elevation of end-tidal CO2 is one of the earliest, most sensitive and specific signs of MH.
However, vigorous hyperventilation may mask such hypercarbia and delay the diagnosis
An impending episode of MH is heralded by a rising end-tidal carbon dioxide level in
the anesthetized patient.
Variations in presentation in MH:
• some patients may undergo multiple anesthetics before experiencing MH.
• may present several hours of anesthesia or rarely in the early postoperative
period, within an hour of discontinuing the anesthesia.
•
In some cases, rigidity is not found at all, and in others, temperature elevation
is unimpressive
Drugs that trigger Malignant Hyperthermia: Isoflurane, Succinylcholine
Tatsukatwa et al, encountered a case of malignant hyperthermia caused by intravenous
lidocaine which had been administered as treatment for a ventricular arrhythmia
Patient-Related: Unelicited pre-existing medical condition: electrolyte abnormalities
• Is patient hyperkalemic or hypokalemic?
disturbance in potassium balance is another cause of intraoperative arrhythmia.
Hyperventilation during anesthesia may result in respiratory alkalosis, reducing serum
potassium concentration and precipitating arrhythmias in an already hypokalemic
patient.
Surgery- Related: incidence of arrhythmia is 61.7% , in relation to different surgical
procedure.
Other contributing factors:
• Missed Injury
• Stabbing victims may have also suffered blunt trauma from being kicked
or otherwise beaten.
• It is estimated that 15% to 75% of patients sustaining blunt chest
trauma may have sustained a Blunt cardiac injury (BCI) and as many as
68% of those patients suffer a complication.
• BCI or “cardiac contusion,” has been dubbed a “capricious syndrome”
because it actually encompasses a wide spectrum of injury with varied
clinical presentations
• The most common mechanism of injury was
•
motor vehicle collision, occurring in 215 (80%) patients;
• 28 (10%) were pedestrians,
• 14 (5%) fell from a height,
• 8 (3%) were assaulted
• 5 (2%) suffered a crushing chest injury
Myocardial contusion may induce severe complications, the most frequent being
arrhythmias.
Arrhythmias may occur after even minor myocardial contusion. It is responsible for the
reentry mechanism potentially leading to severe arrhythmias
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Electrocardiographic abnormalities frequently occur in myocardial contusion, but a
normal electrocardiogram does not exclude the diagnosis.
A prospective by Devitt et. al, determine the frequency and importance of
cardiovascular complications during anesthesia and surgery in patients with blunt
thoracic trauma requiring surgery within 24 hours of admission and injury
Outcome: “there were no differences in the incidences of arrhythmia and hypotension
between patients with or without myocardial injury surviving the operating room.
“All patients with blunt thoracic injury may develop intraoperative arrhythmias or
hypotension.”
Myocardial contusion with structural myocardial damage may induce serious
arrhythmias or conduction.
However, sudden death and arrhythmia also occur in blunt chest trauma patients who
have no clinical evidence of cardiac injury or nocardiac structural damage
Treatment:
Ventricular tachycardia: Amiodarone 150 mg IV over 10 minutes, repeat as needed to
maximum dose of 2.2g in 24 hours: prepare for elective synchronized cardioversion
Recommendations: A complete medical history should be taken from all patients with
trauma
• A llergies
• M edications
• P ast Medical History
• L ast Meal
• E vents of description of injury
ASA standard monitors should be present
• ETCO2 (capnography)
• Pulse oxymeter
• NIBP
• electrocardiography
END discussion:
•
•
21 yrs old
Severe leukocytosis
o Least cause: blunt cardiac injury – only considered in pxs with atleast 3 fracturestroponin I – workup
o
Multiple stab wound – anesthetic vs premorbid condition of patient (identify probable
cause of leukocytosis?)
o
Precaution: HIV test → 7% positive in trauma pxs
o
Hepatitis → 15%
o
Shabu users → 25%
 OBSERVE universal precautions
o
o
Light anesthesia – precipitant to ↑HR & ↑BP → arrhythmia
Anes prelated precautions:
 Poor analgesia – give adequate dose
 Skilled personnel needed – anes,surgeons,nursing staff
END
Transcriber: hazel