DEPARTMENT OF CLINICAL EPIDEMIOLOGY
RESEARCH PROPOSAL
An Analysis of Intra-operative Awareness in the Immediate Post-operative Period among
Ophthalmologic Surgery Patients under General Intravenous Anesthesia using Propofol in
the University of Santo Tomas Hospital
AUTHORS:
FACTON, Rosabelle T.
GERALDOY, Isabelle Reyna G.
KARAAN, Christopher James M.
QUE, Scylla Kneisel C.
TAN, Ernie Joe L.
CO-AUTHOR:
Romulo A. Buzon Jr., M.D.
ABSTRACT
General anesthesia is the induction of a state of unconsciousness with the absence of pain
sensation over the entire body, through the administration of anesthetic drugs like general
anesthetics. General anesthetics depress the central nervous system to a sufficient degree to
permit the performance of surgery and other noxious or unpleasant procedures. They are
considered to have a narrow margin of safety and thus require great care in administration. While
all general anesthetics produce a relatively similar anesthetic state, they are quite dissimilar in
their secondary actions. The selection of specific drugs and routes of administration to produce
general anesthesia is based on patients’ pharmacokinetic properties and on the secondary effects
of the various drugs, in the context of the proposed diagnostic or surgical procedure and with the
consideration of the individual patient’s age, associated medical condition, and medication use.
However, for reasons not clearly understood, some patients under anesthesia experience
unexpected recall of events during surgery that may or may not have psychological implications
in the future.The purpose of this study is to establish a localized report on the incidence of intraoperative awareness in order to provide decision tools that may enable the clinician to reduce the
frequency of unintended intra-operative awareness. Ophthalmologic surgery patients under
Propofol IV will be interviewed post-operatively and will be scored accordingly. Patients will be
assigned to the recall group if their first post-induction memory is related to intra-operative
events; and to the non-recall group if their first post-induction memory is related to events
occurring after completion of surgery. Data of the study will be reported as the incidence of
intra-operative awareness among the subjects.
An Analysis of Intra-operative Awareness in the Immediate Post-operative Period among
Ophthalmologic Surgery Patients under General Intravenous Anesthesia using Propofol in
the University of Santo Tomas Hospital
RESEARCH QUESTION
What is the incidence of intra-operative awareness among ophthalmologic surgery
general anesthetized cases (using Propofol IV) in the University of Santo Tomas Hospital; and
what may be the contributing factors?
HYPOTHESIS
Null hypothesis: There will be no incidence of intraoperative recall on patients after general
anesthesia (Propofol IV).
Alternative hypothesis: There will be incidence of intraoperative recall on patients after
general anesthesia (Propofol IV).
GENERAL OBJECTIVE
1. To determine the incidence of intraoperative awareness among general intravenous
anesthetized ophthalmologic surgery cases using Propofol IV in the University of Santo
Tomas Hospital.
SPECIFIC OBJECTIVE
1. To determine the extent of recall of patients under the general intravenous anesthesia
using Propofol.
INTRODUCTION
General anesthethics today are the most potent depressors of nervous system activity used
in medicine. They affect even the regulation of breathing and heart function. Because of this,
these drugs are considered to have a narrow margin of safety. For this reason, individuals
undergoing emergency operations, such as trauma victims whose lung and cardiovascular
function is already unstable , or patients in the midst of heart surgery must receive a lighter than
normal dose of anesthesia, which could make them susceptible to brief awareness incidents
(Beverly A. Orser, Scientific American, June 2007, www.sciam.com).
All of today’s general anesthetic drugs were developed empirically; they were tested for
their ability to produce the desirable effects that define the anesthetized state. The physiologic
state of general anesthesia includes sedation (reduced arousability), unconsciousness (also
sometimes called hypnosis), immobility, absence of pain (analgesia) and absence of memory for
the anesthetized period (amnesia). Studies have shown that activity of these potent drugs
involves highly specific interactions with subpopulations of nervous system cells to create each
of the separate properties of anesthesia.
Anesthetics are categorized based on whether they are delivered by inhalation, such as
isoflurane, or intravenously, such as propofol. These drugs induce a state of a pharmacological
coma, which is a deep sleep. They prolong the duration of postsynaptic electric currents
generated by GABAA receptors.
Intravenous anaesthetics have an onset of anaesthetic action faster than the fastest of the
inhaled gaseous agents such as desflurane and sevoflurane, making them the agents commonly
used for induction of anaesthesia. Both the desirable and unwanted effects of anaesthetic drugs
came from their ability to suppress neuronal activity throughout the central nervous system.
Propofol, 2,6,-diisopropylphenol, has been in use in the Unites States since November, 1989.
Propofol is a low molecular weight (178D) molecule that is virtually insoluble in water and is
highly soluble in fat. Propofol infusions are often combined with opioid infusions during
anesthesia. Since the decline in propofol concentration is several folds faster than the decline in
opioid concentration, it makes pharmacokinetic sense to titrate the propofol while maintaining a
constant opioid concentration. Propofol's pharmacokinetic characteristics of extremely rapid
metabolism and large distribution clearances relative to distribution volumes result in a unique
disposition that is well suited to both induction and maintenance of anesthesia. Patients in
hypovolemic shock should not be induced with propofol (Intravenous Anesthesia: Techniques
and New Drugs by Steven L. Shafer, M.D., Donald R. Stanski M.D.). The anaesthetic potency of
intravenous anaesthetics, including thiopental, ketamine, and propofol, is enough to allow their
use as the sole anaesthetic in short surgical procedures when combined with nitrous oxide and
opioid analgesics. Adjunctive use of potent opioids, such as fentanyl, contributes cardiovascular
stability, enhanced sedation, and profound analgesia. However, pre-anaesthetic administration of
benzodiazepines, having a slower onset, can provide a basal level of sedation and amnesia (Basic
and Clinical Pharmacology, 9th Edition 2004).
Anaesthetics are known to cause amnesia at doses considerably lower than those required
for unconsciousness or immobility. Yet for some reasons, some patients experience unexpected
recall of events during the surgery itself. Episodes of intraoperative awareness while under
general anaesthesia are reported by one or two of every 1,000 patients. The risk of intraoperative
awareness seems to vary among types of procedures. The reported incidence of patient
awareness during anesthesia depends on the type of anesthesia, strength of the stimulus, and the
timing and persistence of attempts to elicit recall. Several resources report the overall incidence
of IOA is 0.2% to 1% of the 18.6 million anesthetized procedures performed each year. Cesarean
section procedures pose a 2% to 28% risk of awareness; major trauma procedures, 11% to 43%:
cardiopulmonary bypass procedures, 1.14% to 23%; and bronchoscopy procedures, 8%. One
study limited to "fast-track" cardiac surgical patients cited an incidence of 3.3%. (Monitoring for
Intraoperative Awareness, Oullette, Sandra M.; Simpson, Chrysanne AORN Journal 12/1/1998)
REVIEW OF RELATED LITERATURE
Intraoperative awareness under general anaesthesia is a rare occurrence, with a reported
incidence of 0.1-0.2% (Myles et al., 2000). Significant psychological sequelae (e.g., post
traumatic stress disorder) may occur following an episode of intraoperative awareness, and
affected patients may remain severely disabled for extended periods of time (Lennmarken et al.,
2002). In some circumstances, intraoperative awareness may be unavoidable to achieve other
critically important anaesthetic goals.
In the Philippines, however, the incidence of intraoperative awareness has not yet been
fully established. Thus, this study will provide a localized report on the incidence and
contributing factors to intraoperative awareness.
Awareness is the post-operative recall of events that takes place during general
anesthesia. It is an uncommon problem of anesthesia in the adult surgical population, with an
incidence of 0.1%–0.2%. In adults, awareness is often a distressing event and may have
significant psychological ramifications. There are only few studies known about awareness in
modern pediatric anesthesia. One study last June 1993, Recall of Intraoperative Events after
General Anaesthesia and Cardiopulmonary Bypass by Phillips et al. reported an incidence of
awareness with subsequent recall of intraoperative events of 1.14% in patients undergoing
cardiopulmonary bypass with a low-dose narcotic, balanced anesthetic technique in which
evaluation of patients undergoing cardiopulmonary bypass for cardiac surgery was done to assess
the incidence of the problem and determine any obvious causes of intraoperative awareness.
Anesthesia was induced with diazepam or midazolam (1-10 mg), fentanyl (10 μg • kg-1) and
when required, thiopentone sodium (0.2-2.0 mg • kg-1). Muscle relaxation was achieved with a
bolus of pancuronium (0.12 mg • kg"1). Anaesthesia was maintained with a volatile agent,
primarily halothane, with additional boluses of diazepam and fentanyl at the discretion of the
anaesthetist. During bypass isoflurane was entrained and benzodiazepines injected into the
bypass circuit to help achieve the desired mean perfusion pressure. Post-bypass a volatile agent
was introduced in the presence of adequate cardiovascular stability. The records of patients
reporting intraoperative recall and of 60 randomly selected patients without recall were further
scrutinized to determine the percentage of time volatile agents were entrained in the pre-bypass,
bypass and post-bypass periods. Out of a total of 837 patients who underwent cardiopulmonary
bypass from the 16th March 1990 to 31st October 1991 majority of patients underwent coronary
artery bypass surgery. Seven hundred patients (84%) completed the postoperative interview,
their average age, duration of CPB and aortic cross-clamping. The first post-induction recall was
intraoperative in eight patients, resulting in a 1.14% incidence of recall of intraoperative events.
A subsequent detailed review of the charts of the eight patients who reported recall and of 60
randomly selected non-recall patients' charts revealed there was no difference in the percentage
of time volatile agents were entrained in the pre-bypass, bypass and post-bypass periods of the
operation. Episodes of awareness seemed to occur at any time during the operation. Because
cooling is associated with a decreased level of consciousness and lowered metabolic rate, we
wondered if patients undergoing normothermic bypass might have a higher incidence of recall.
We were unable to demonstrate an effect of temperature on recall. The smaller number of
patients with recall precludes drawing any definitive conclusions on the effect of temperature on
recall in these patients. Preliminary power calculations show that to have an 80% power for
detecting a halving of the 2% incidence found in the warm patients, 2100 patients per group
would have to be studied. Given the problems with monitoring the depth of anaesthesia and the
limitations imposed on the investigators by the surgery it is not surprising that there is a
measurable incidence of recall in these patients. The incidence that we report following CPB is
much lower than in two previously published studies of cardiac surgery patients.
Another study, Awareness during Anesthesia in Children: A Prospective Cohort Study by
Davidson et al. performed in 2005, wherein from one-thousand-two-hundred-fifty children
recruited into the behavior study, only 864 children remained and had at least 1 assessment for
awareness. Seven-hundred-fifty-six (88%) were assessed within 1 day of the procedure, 704
(81%) at Day 3, and 590 (68%) at 30 days. The principal investigator interviewed 28 children
who had suspected awareness from the screening questions. Twenty-eight reports were generated
and sent to the adjudicators. In 12 cases, at least 1 adjudicator reported the case as “awareness.”
There were 7 cases of true awareness for an incidence of 0.8% (95% confidence interval, 0.3%–
1.7%). Cases that were not classified as “awareness” were usually children with auditory
memories of events that could have occurred in recovery and children with inconsistent or
contradictory memories. The awareness assessment was nested within a larger detailed study of
predictors of behavior change in children after hospitalization and anesthesia. This article
presents only the awareness data. Because of differing anesthesia requirements and techniques, it
is possible that the incidence of awareness differs significantly in children, who, compared to
adults, also have different expectations, fears, and ways of managing stressful events. The
prevention of awareness continues to be a priority for anesthesiologists.
SIGNIFICANCE
General anaesthesia is one of the primary modes of anaesthesia used in hospitals today
for major surgeries, either elective or emergency procedure, in the operating rooms. The aim of
general anesthesia is to provide a condition characterized by unconsciousness, muscular
relaxation and the suppression of reflex response to noxious stimuli. The problem which
continues to disappoint anaesthetists is our limited ability to assess our patients' level of
consciousness. Debate have been made regarding the status of the consciousness of patients if
intra-operative information is presented them, this correlates to the consciousness of the patient
during those times and check on recall postoperatively. With the use of muscle relaxants and
balanced anaesthesia, the assessment of depth of anaesthesia is difficult.
There have been studies that showed that there is a considerable evidence that specific
information both perceived during anaesthesia and remembered following surgery (Merikle and
Daneman). But there are also studies contradicting this, saying that anaesthesia such as
inhalation ones doesn’t have effect on implicit or explicit memory during anaesthesia and is not
recalled after the surgery (Wang and Russell, 1997).
Another study conducted also by Russell and Wang showed that intravenous injection
using Propofol and Alfetanil showed no significant result on the presence of either explicit or
implicit memory. This discrepancy led to the importance of verifying this information because
awareness during major surgery is one of the important considerations in anaesthesia as presence
of awareness may lead to traumatic experience related to unfamiliar surgical procedure, painful
sensation and fear of the unknown.
However, when propofol is used without N2O or a potent vapor, there is the possibility of
intraoperative awareness.
Although intraoperative awareness can also occur when using a
N2O/opioid anesthetic technique, NO is a sufficiently potent analgesic that intraoperative
awareness of pain almost never occurs during when using N2O with an opioid. This is not the
case with propofol. Intraoperative awareness during a propofol/opioid technique (e.g. during
total intravenous anesthesia) may include awareness of intraoperative pain (Intravenous
Anesthesia: Techniques and New Drugs by Steven L. Shafer, M.D., Donald R. Stanski M.D.). In
one study, the investigators reported a case of awareness and recall during propofol anesthesia
combined with epidural anesthesia in a patient scheduled for a resection of left ovarian tumor.
After induction, anesthesia was maintained with propofol and epidural anesthesia. About one
hour into maintenance, the patient was moving with haemodynamic signs suggesting inadequate
analgesia. Immediately after extubation, the patient could recall the abdomen being touched
during laparotomy. This case indicates that even if appropriate dose of propofol is administrated,
intraoperative awareness may occur especially with inadequate analgesia. (Sakio H, Saitoh K,
Inoue S, Nakaigawa Y, Hirabayashi Y, Seo N.). As was in a study wherein a woman with mild
liver dysfunction underwent lower abdominal surgery, anesthesia was induced with propofol 60
mg and fentanyl 0.1 mg. Tracheal intubation was facilitated with vecuronium 8 mg, and the
lungs were ventilated with 33% oxygen in air. The bispectral index (BIS) was continuously
monitored. Anesthesia was maintained with propofol infusion and analgesia was provided by
thoracic epidural infusion of lidocaine 1.5%. The infusion rate of propofol was altered to
maintain the BIS value between 40 and 50. The patient was hemodynamically stable with
propofol 1.5 mg.kg-1.hr-1 and the BIS value was maintained about 40 during the operation. Near
the end of the operation the patient moved suddenly. Suspecting inadequate anesthesia, a total of
40 mg of propofol IV and 5 ml of the epidural infusion were given. Immediately before the
movement the BIS value was about 40. The operation was completed 30 min later. On discharge
from the operating room the patient declared that she had been awake. She had heard voices and
felt the surgeon working, but had suffered no pain. The BIS is a useful indicator for hypnotic
effect, but this case demonstrates that awareness might occur even when BIS value indicates
adequate hypnotic state. (Kurehara K, Horiuch T, Takahash M, Kitaguchi K, Furuya H. Surgical
Center, Nara Medical University, Kashihara)
SCOPE AND LIMITATIONS
1. The Study will be conducted at the university of Santo Tomas Hospital only.
2. This study will only include surgeries of general anesthesia using Propofol IV.
3. This study will only include ophthalmologic surgery patients.
4. This study will not include patients younger than 3 years old, safety and efficacy of
Propofol at this age have not been established for maintenance anesthesia.
5. The subject should be able to respond to the questions. Patients with neurotic disorders,
under comatose, mute, deaf, or other causes that will render them unfit to be
interviewed are all excluded.
6. Patients who have had a history of mental instability, and alcohol and substance abuse
will not be included in the study population.
7. Long term effects of intraoperative recall are not included in this study.
8. Interviews will be done post-operation, at a time and condition deemed appropriate by
the anaesthetist and attending surgeon.
9. The sampling of subjects is purposive.
BUDGET
For this study, there will be minimal expenses which will mainly be distributed in the
production of the final paper (e.g. printing, binding, photocopying). The study proper is of
interview-survey type only and will not therefore require any sort of cost.
METHODOLOGY
This is a prospective cohort study. A post-anesthetic review will be performed. Included in this
assessment is a structured interview relating to intraoperative recall. A series of questions will be
asked to the patients. Table 2 and 3 summarizes these questions and the indications of their
replies. Post-anesthesia recovery score of Aldrete will be noted. This score records vital signs
with patients receiving 0-10 points: 0-2 points for five physiological variables (Table 1). A high
score is indicative of full recovery.
Table 1. Post-anesthesia recovery score
Aldrete Scoring System for Conscious Sedation
Activity



Voluntary movement of all limbs to command -2 points
Voluntary movement of two extremities to command- 1 point
Unable to move- 0 points
Respiration



Breathe deeply and cough- 2 points
Dyspnea, hypoventilation- 1 point
Apneic- 0 points
Circulation



BP +/- 20 mm Hg of pre-anesthesia level- 2 points
BP > 20-50 mm Hg of preanesthesia level- 1 point
BP > 50 mm Hg of preanesthesia level- 0 points
Consciousness

Fully awake- 2 points


Arousable- 1 point
Unresponsive- 0 points
Color
 Pink- 2 points
 Pale, blotch- 1 point
 Cyanotic- 0 points
Total score must be > 8 at conclusion of monitoring.
Table 2 Post-anesthetic review questions and indication of replies
Question
What is the last thing you remember
before going to sleep?
What is the very next thing you
remember upon waking up?
Can you remember anything in between
these two events?
Did you have any dreams?
Indication
Site of the last pre-induction recall
Site of the first post-induction recall
Evaluation of recall
Table 3 Structured Awareness Screening Interview
1. Were you upset, worried, or frightened about your operation?
2. How upset, worried, or frightened were you?
3. What was the last thing you remember before the operation?
4. How did the doctor make you go to sleep?
5. What is the next thing you remember after the operation?
6. Did you have any dreams or feel or hear anything while you were having the operation?
7. Were you sore after the operation?
8. How much did it hurt?
9. What did you like least about having an operation?
10. What did you like best about having an operation?
11. Did someone talk to you about what the operation was going to be like?
12. Was that about the same as what happened?
13. How do you feel about the operation?
14. Would you like to have known more?
Patients will be assigned to the recall group if their first post-induction memory related to
intraoperative events; and to the non-recall group if their first post-induction memory related to
events occurring after completion of surgery. A review of anesthetic charts will provide a record
of the dosages of premedications, induction agents and drugs employed to maintain anesthesia.
Sample Results
Table 4 Patient characteristics
Sex
Age
Male
Female
18-30 years old
31-50 years old
>50 years old
Table 5 Detail of awareness
Period of Time
Induction
Maintenance
Post-operative
Remembrance
Sound
Pain
Paralysis
Table 6. Possible contributing factors
Factor
Awareness
37
62
0
89
10
Percentage
37.37
62.63
Awareness
Percentage
Awareness
Percentage
Type of surgery
Site of surgery
Dosage of anesthesia
During the consent process, the family will be informed that the study was a survey of
intraoperative recall of events after general anesthesia. After a detailed explanation of the
questionnaires needed for the assessment, the family will also be informed that there would be
questions about the patients’ memories and experiences in the period around the anesthetic.
Anesthesiologists will be informed about the awareness study before it started. Once the patient
is already in the recovery room, the anesthesiologist will be asked to provide details of anesthetic
technique and a description of any critical incidents. Screening questions will be asked once
post-surgery to detect possible awareness. The screening interview will be during the hospital
stay. For day-stay patients, this will be performed just before discharge. For in-patients, the
interview will be on either the same day or the next day if the patient is unwilling or unable to
talk on the day of the anesthetic. During this interview, the awareness screening questions will be
inserted among data collected for the intraoperative awareness study. The questions are listed in
Table 2 and 3. The same questions will be used for all patients. If the patient answered “no,” then
the screening questions will not be repeated. No incentives will be given for the patient to
answer, and no leading questions will be asked during the screening interview. If the patient
answered “no” to Question 6 on Table 3, there will be no further prompting. If the patient
answered “yes,” and if we thought there is a possibility that the answer represented awareness,
then we will take note of the data. The screening questions will be asked by the authors. A
memory was classified as a dream if the patient considered the memory to be a dream. When any
potential cases of awareness are identified, the anesthesiologist who performed the anesthetic
will be informed. Any comment by the anesthesiologist that is relevant to the possible awareness
event will be recorded.
Possible contributing factors pertaining to the dosage difference and the site of surgery
will be investigated and presented as shown in Table 6.
An estimate of the necessary sample size will be based on the intention of confidently
excluding the possibility of not detecting an incidence of awareness.
Patients experiencing awareness during surgical procedures performed under general
anesthesia may subsequently recall intraoperative events. To reduce bias, an effort will be made
to keep the profile of this study low. However, as the study progresses, the anesthesia staff
becomes more familiar with the study. It is not possible to blind the anesthesia staff, for ethical
and medico-legal reasons. It is also useful to be able to gather information about the case from
the involved anesthesiologist. It is possible that as the profile of the study gradually increased,
the anesthesia staff changes their routine practice.
CONCEPTUAL FRAMEWORK
CAUSATIVE FACTOR
Inadequate level of anesthesia
INTERMEDIATE EFFECTS
(CONFOUNDERS)
- Interpatient pharmacokinetic and
pharmacodynamic variability
-Inadequate anesthesia
(wrong dosage calculation)
-Reduced or no use of premedication
(adjunctive drugs, e.g. fentanyl and
midazolam)
- Equipment failure (perfusor pump
failure, inaccurate manual titration
improperly calibrated or connected
vaporizers, empty vaporizers, general
problems with anesthesia machines)
PRESENCE OF INTRAOPERATIVE
AWARENESS
SAMPLING DESIGN
Non-Probability- Purposive Sampling
A. Inclusion Criteria

18 years old and above (Age Range: 18-80 years old)

scheduled for ophthalmologic surgical operation (ASA I and II Surgeries) in the UST
Hospital
 Examples: Cataract extraction, lensectomy, lacrimal endoscopy

those who will be under Propofol anesthesia via intravenous injection
B. Exclusion Criteria

those with psychological deficit or illness

those with head trauma and/or disease affecting cognition and memory
SAMPLE SIZE CALCULATION
n ≥ [Np (1-p)] / [(N-1)D + p(1-p)]
D= (Margin of Error)2 / (za/2)2
n – Sample size
N – Population size
P – Prior assumption of the population parameter
If the level of confidence is 95% then α = 5% then z value is 1.96 (D = 0.00065077)
If the Total Population size (N) is 1000, margin of error is ±5% and the P is 10%
n ≥ [Np (1-p)] / [(N-1)D + p(1-p)]
n ≥ [(1000*0.10) (1-0.10)] / [(1000 – 1)(0.00065077) + (0.10)(1 – 0.10)]
n ≥ [(100) (0.90)] / [(999)(0.00065077) + (0.10) (0.90)]
n ≥ [90] / [(0.65011923) + (0.09)]
n ≥ [127.5] / [0.74011923]
n = 121.6020 ≈ 122
The calculated sample size is 122. This is the minimum recommended size for the study.
STATISTICAL ANALYSIS
Data of the study will be reported as the incidence of intraoperative awareness among the
subjects. The following formula will be used to achieve this:
Incidence Proportion =
Subjects who experienced intraoperative recall
----------------------------------------------------------- x 100
Total subjects assessed within a given period of time
Basically, incidence involves: a condition; a source population at risk of the condition;
and the passage of time during which events occur. It could be reported as either incidence rate
or incidence proportion. Incidence rate takes into account what happens from moment to
moment. One disadvantage of this is that it assumes that the rate is constant over different
periods of time. Incidence proportion, on the other hand, is the incidence calculated using a
period of time during which all of the individuals in the population are considered to be at risk
for the outcome. It is sometimes referred to as cumulative incidence or the attack rate.
TIMETABLE
Date
Activity
June-October 2007
November 2007-March 2008
June 2008-June 2010
July 2010
August 2010-September 2010
October 2010
November 2010-March 2011
Research Protocol Presentation
Research subgroup discussion: planning level
Drafting of protocol
Submission of final research protocol
Research Proper
Sample size selection
Distribution and collection of informed consent
Conduction of interview/scoring
Data collection
Final collection of data
Interpretation and analysis of data
Research paper
Final research output
Presentation of final research output
Submission of final research output (including input from
the Review Board)
GANTT CHART
Activity
JuneOct
2007
Subgroup
discussion
Drafting of
Protocol
Submission
of final
research
protocol
Research
Proper
Sample size
selection
Informed
consent
Interview
Analysis of
data
Research
paper
Final
research
output
Submission
Nov
2007Mar
2008
Timeline
June 2008-June
July
2010
2010
AugSept
2010
Oct
2010
Nov
2010Mar
2011
Since the study will involve human subjects, free and informed consent will be secured in order
to conform to ethical concerns. This will be done by allowing the subjects to thoroughly read and
voluntarily sign a form that will be written in the language that they would understand best
(English/Filipino). All the important details of the study that are of the subjects’ concern which,
on the other hand, would not generate any bias will be included in the consent. Also, they will be
assured that their identities will not be revealed in the least manner. Sample informed consent is
as follows:
[Date]
INFORMED CONSENT FORM
University of Santo Thomas
Faculty of Medicine and Surgery
An Analysis of Intra-operative Awareness in the Immediate Post-operative Period among
Ophthalmologic Surgery Patients under General Intravenous Anesthesia using Propofol in
the University of Santo Tomas Hospital
Rosabelle T. Facton, Isabelle Reyna G. Geraldoy, Christopher James M. Karaan,
Scylla Kneisel C. Que and Ernie Joe L.Tan
You have been asked to take part in a research project described below. The researcher will
explain the project to you in detail. You should feel free to ask questions. The investigator in
charge will discuss them to you.
Description of the project:
You have been asked to take part in the study that will investigate on the effects of general
anesthesia IV propofol on intraoperative recall of patients undergoing ophthalmologic surgeries.
The incidence of recall, according to previous studies, is rare. You are being asked to volunteer
in the research because you have been found to fit the criteria needed. These include the type of
surgery to which you will be subjected, the anesthesia to be used in your surgery, age,
psychological health, and absence of history of any problem regarding memory. Other potential
subjects are also being asked to volunteer for this research.
Procedures:
If you decide to take part in this study here is what will happen:
After the operation, post-recovery, you will be interviewed to assess any intraoperative
awareness. It will be conducted in your room to avoid any inconveniences. One to three
investigators will be present during the interview. It will only be done once and would expect to
last within 30 minutes. We do expect your full cooperation and honesty in answering the
questions provided.
Risks or discomfort:
If intraoperative awareness is indeed present, discomfort in recalling the events is possible. But
for clarification, the study will have no control over the type of surgery you will be subjected
into and the anesthesia to be used. The study merely chooses potential subjects who fit the
criteria set for the investigation.
Benefits of this study:
Although there will be no direct benefit to you for taking part in this study, the researcher may
learn more about the link between intraoperative awareness and Propofol and might benefit
future patients.
Confidentiality:
Your part in this study is confidential. None of the information will identify you by name. All
records will be kept in a secure place only the investigators know of.
Voluntary participation and withdrawal:
Participation in research is voluntary. You have the right to refuse to be in this study. If you
decide to be in the study and change your mind, you have the right to drop out at any time.
Whatever you decide, you will not receive penalty.
Questions, Rights and Complaints:
If you have any questions about this research project, please call Ysa at +639154536741 or Scy
+639273352480 or email at clin_epi@yahoogroups.com.
Consent statement
By signing this document you consent to participating in “An Analysis of Intra-operative
Awareness in the Immediate Post-operative Period among Ophthalmologic Surgery Patients
under General Intravenous Anesthesia using Propofol in the University of Santo Tomas
Hospital” being given by the medical students at the University of Santo Thomas Faculty of
surgery whose names appear above.
This statement certifies the following: that you are 18 years of age or older and you have
read the consent and all your questions have been answered. You understand that you may
withdraw from the study at any time and will not be penalized.
All of the answers you provide will be kept private. You should know that you have the right to
see the results prior to their being published.
A copy of the informed consent will be given to you.
__________________________________
Signature over Printed Name of Participant
__________________________
Date
REFERENCES
(1) Andrew J. Davidson, MBBS, GradDipEpiBiostats, FANZCA, Grace H. Huang,
BMedSci,
(2) Caroline Czarnecki, BMedSci, Margaret A. Gibson, BN, RN, Stephanie A. Stewart, BN,
RN,Kris Jamsen, BSc, PGDip(Stats), and Robyn Stargatt, PhD, MAPS Awareness during
Anesthesia in Children: A Prospective Cohort Study, Department of Anaesthesia, Royal
Children’s Hospital, Flemington Rd., Parkville 3052, Victoria, Australia.Anesth Analg
2005;100:653–61
(3) Andrew A. Phillips MBChB FCAnaes, Richard E McLean MD FRCPC, J. Hugh Devitt
MD MSC FRCPC, Ellen M. Harrington BA. Recall of intraoperative events after general
anaesthesia and cardiopulmonary bypass
(4) Basic and Clinical Pharmacology, 9th Edition 2004
(5) Beverly A. Orser, Scientific American, June 2007, www.sciam.com
(6) Kurehara K, Horiuch T, Takahash M, Kitaguchi K, Furuya H. A case of awareness
during propofol anesthesia using bispectral index as an indicator of hypnotic effect.
Surgical Center, Nara Medical University, Kashihara 634-0813 PMID: 11554023
[PubMed - indexed for MEDLINE]
(7) Lennmarken et al., 2002
(8) Merikle and Daneman
(9) Myles et al., 2000
(10) Oullette, Sandra M.; Simpson, Chrysanne. Monitoring for Intraoperative Awareness,
AORN Journal 12/1/1998
(11) Sakio H, Saitoh K, Inoue S, Nakaigawa Y, Hirabayashi Y, Seo N. Intraoperative
awareness during propofol anesthesia with epidural anesthesia Department of
Anesthesiology and Clitical Care Medicine, Jichi Medical School, Tochigi 329-0498.
PMID: 12428327 [PubMed - indexed for MEDLINE])
(12) Steven L. Shafer, M.D., Donald R. Stanski M.D. Intravenous Anesthesia: Techniques and
New Drugs
(13) Wang and Russell, 1997
(14) http://www.becomenatural.com/blog/2007/09/introduction-to-general-anesthetics/
(15) http://www.healthline.com/galecontent/anesthesia-general
BIOGRAPHICAL SKETCH
Rosabelle Tababa Facton
24 years old
#95E Cristobal Street Sampaloc, Manila
2007- Present, Third Year Medical Student, Faculty of Medicine and Surgery, UST
College:
Bachelor of Science in Biology
University of the Philippines Diliman
rovifacton@yahoo.com
Experience in Research: College Thesis
Effects of Dietary Oils on Metabolic Rate, Blood Glucose, Body Temperature and Body
Weight of Mice
Isabelle Reyna G. Geraldoy
23 years old
76 Jasmin Street, Roxas District, Quezon City 1103
2007- Present, Third Year Medical Student, Faculty of Medicine and Surgery, UST
College:
University of the Philippines Manila
Bachelor of Science in Biology
sabby08_g@yahoo.com
Research Experience: College Thesis:
Water Quality Assessment of Laguna Lake Using Developmental Biomarkers in Cane
Toad (Bufo marinus) Embryos
Christopher James M. Karaan
23 years old
500 Bagbag Seminary Rd. Novaliches, Quezon City
2007- Present, Second Year Medical Student, Faculty of Medicine and Surgery, UST
College:
University Of Santo Thomas
Bachelor of Science in Medical Technology
Experience in Research: College Thesis
A Study on the Antibacterial Activity of Aqueous Extracts of Parsley (Petroselinum
crispum) Against Clinical Isolates
Scylla Kneisel C. Que
24 years old
11F North Road San Gabriel Village Tuguegarao City 3500
scykneisel02@yahoo.com; wylanski23@yahoo.com
2007- Present, Third Year Medical Student, Faculty of Medicine and Surgery, UST
College:
University of Santo Tomas
Bachelor of Science in Pharmacy
Experience in Research: College Thesis
Comparative Studies of the Phytochemical, Toxicological and Antioxidant Properties of
the two cultivars of Ipomoea aquatica var. Forsk. (Convolvulaceae) from Tanauan and
Talisay, Batangas
Ernie Joe L. Tan
23 years old
1246 Pedro Gil St. Paco, Manila
erniejoetan@yahoo.com; kngarthr2000@yahoo.com
2007- Present, ThirdYear Medical Student, Faculty of Medicine and Surgery, UST
College:
University of SantoTomas
Bachelor of Science in Medical Technology
Experience in Research: College Thesis
The Larvicidal Effect of Anona Muricata (Guyabano) Seed Extract Against Mosquito
Larvae
Romulo A. Buzon Jr., M.D., DPBA, FPBCA,
Professor I, Faculty of Medicine and Surgery
Department of Epidemiology, Anesthesiology, and Physiology UST
Thoracic and Cardiovascular Anesthesiology
dr_buzon@yahoo.com