Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT01442740 |
| Other study ID # |
RTP-2011 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
September 26, 2011 |
| Last updated |
August 28, 2013 |
| Start date |
October 2011 |
| Est. completion date |
May 2012 |
Study information
| Verified date |
August 2013 |
| Source |
St. Paul's Hospital, Canada |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
Canada: Health Canada |
| Study type |
Interventional
|
Clinical Trial Summary
Functional Endoscopic Sinus Surgery (FESS) is normally performed in our centre in a 0-degree
supine position, with the patient laying flat. This study will be investigating whether
changing patients to a 15-degree head up, feet down position will improve field of view and
reduce blood loss during surgery. The 15-degree head up, feet down position has been used in
other circumstances, such as brain surgery and for severely obese patients where airways can
be blocked due to lying flat. Every 15 minutes, blood pressure, heart rate and field of view
according to the Boezaart nasal scope scaling system will be recorded.
Description:
Our objective is to determine whether 15-degree RTP during FESS will influence
intra-operative blood loss and surgical field scores when compared to patients in a supine
position.
Our hypothesis is that the 15-degree RTP position is not inferior to the supine position in
reducing intra-operative blood loss and improving surgical field view during FESS.
Specific Aims
Aim 1: To determine the effect of 15-degree RTP on total blood loss, time of surgery and
endoscopic surgical view, when compared with patients in the supine position, during FESS.
Participants will have their sinus cavities assessed by rigid endoscopy during surgery. The
Boezaart scaling system will be used as our primary endoscopic surgical field measure. Total
Blood Loss (TBL), Mean Arterial Pressure (MAP), pulse rate and Time of Surgery (TOS) will be
recorded intra-operatively by the anesthesiologist and supporting nurse staff. The results
of this experiment will determine whether utilizing the 15-degree RTP is effective to reduce
blood loss during ESS.
Background and significance:
Chronic Rhinosinusitis (CRS) is associated with nasal obstruction, discolored nasal
discharge, facial congestion or pressure that lasts at least twelve weeks (1,2). Nasal
polyposis may also be present with CRS (1,2). Corticosteroids and medicated nasal
irrigations are recommended as preliminary treatment options3. Sinus surgery is recommended
for patients whose symptoms are refractory to maximal medical management. FESS has evolved
to become the preferred surgical method for treating CRS and other sinus related diseases4.
When compared to the previous open craniofacial approach, this technique has been found to
be less invasive, low-risk and reduces operating time with improved post-operative
outcomes4. FESS performed in the supine position has been the standard at the St. Paul's
Sinus Centre. Surgeon experience has indicated that patients in a 0-degree operating
position, allows for consistent orientation of the sinus anatomy. However, bleeding within
the surgical area can obscure endoscopic field of view, increasing risk for surgical
complications which may include cerebrospinal fluid leak, hemorrhage, infection and damage
to the optic nerve and internal carotid artery (4,6). There are several factors available to
control hypotension during surgery such as the use of total intravenous anesthesia (TIVA),
pre-operative topical treatment with steroids, local vasoconstrictors and patient position4.
TIVA has been observed to reduce intra-operative hemorrhage by lowering mean arterial
pressure (MAP) when compared to inhalational anesthesia during ESS5. The use of
corticosteroids prior to surgery has been found to reduce peri-operative blood loss (6).
Results indicate that TIVA and pre-operative steroid treatment can significantly lower
surgical grade scores by improving endoscopic visualization (5,6). However, altering patient
position during the operation may provide a simple option to further reduce the presence of
blood within the surgical field.
The Reverse Trendelenburg Position (RTP) is a head-up, feet-down tilt varying from 10 to 30
degrees (7). When used in surgery, RTP has been found to reduce hydrostatic forces and
venous congestion (6,7). In morbidly obese patients where anesthesia can alter respiratory
function RTP has been identified as a safe intra-operative procedure, improving oxygenation
with minimal MAP changes (9). This position has been found to reduce intra-cranial pressure
during craniotomy and thereby, decreasing surgical risks for cerebral swelling and
herniation (8).
The role of RTP and other factors related to intra-operative blood loss during FESS has
recently been examined. Ko et al. (2008) equally randomized 60 CRS patients to receive FESS
while in the 10-degree RTP or complete supine position. Patients with CRS with or without
nasal polyposis, mild or moderate hypertension, diabetes, chronic renal disease, and other
uncritical medical conditions were included in the study (10). Patients were excluded if
they had severe or uncontrolled cases of hypertension, cardiovascular disease and
preoperative use of anticoagulant medication (10). All patients received a combination of
intravenous and inhaled anesthesia. This was induced with fentanyl, xylocaine, propofol and
cisatracurim. Desflurane or sevoflurane were used intra-operatively to maintain anesthesia
(10). In addition, a 1% solution of lidocaine hydrochloride, a local anesthetic, and
adrenaline at a dilution of 1:80,000 was injected into the surgical field and
pterygopalatine fossa. Total blood loss (TBL) was measured from the suction bottle during
the surgery by an OR nurse. Blood loss per minute (BL/Min) was calculated from dividing the
TBL by the total time of the surgery. The Boezaart grading system was used to evaluate the
effect of bleeding within the surgical field (SF). The inverse trendelenburg position was
found to significantly reduce TBL (P < 0.001), BL/Min (P < 0.001) and SF score (P < 0.004).
Due to the highly vascularized nature of the paranasal sinuses, small amounts of blood can
cause substantial impairment to endoscopic view. The RTP reduces venous return and cardiac
output by retaining blood in the lower parts of the body (10,11). As a result, reduced
intraoperative blood loss has been reported in previous studies employing this operating
position during surgery (10,11,12). Although RTP has been utilized in Otorhinolaryngology,
the previously mentioned study used a combination of total intravenous and inhaled
anesthesia for study subjects (10). Previous literature has shown that TIVA can reduce
intra-operative blood loss when compared to inhaled anesthesia5. We aim to evaluate if
15-degree RTP with patients receiving TIVA and preoperative steroid treatment can reduce
endoscopic visual impairment.
Experimental Design and Methods:
Research Method:
Randomized unblinded, prospective study
Recruitment of CRS patients
Patients requiring endoscopic sinus surgery will be approached to partake in this study.
These patients are individuals who have failed conventional medical therapy and require the
expertise of a tertiary rhinologist in treating their sinus disease. This tertiary based
rhinology centre averages 6000 outpatient visits and >400 FESS cases a year. This is the
busiest rhinology centre in Western Canada. The site coordinator or one of the Principal
Investigator's designates will describe the study design to the patients. Patients will have
up to one month prior to surgery to sign the consent form if they plan to partake in the
study. Patients placed in the study will be provided with the direct line to the St. Paul's
Sinus Centre and therefore can talk to any of the co-investigators if they have any
questions or concerns.
Inclusion Criteria:
- Patients 19 years of age or older
- Patients who will undergo primary or revision functional endoscopic sinus surgery
(FESS)
- Patients with CRS with or without polyposis
Exclusion Criteria:
- Patients under the age of 19
- Patients with a history of coagulation disorders
- Patients with severe or uncontrolled cases of hypertension and cardiovascular disease
- Patients undergoing sinonasal tumor resection
Experimental and Control Arm All patients are treated with a one-week course of prednisone
20mg once a day and oral antibiotics (clavulin or clindamycin if penicillin allergic) prior
to surgical intervention. Patients will be randomized to the experimental (15-degree RTP) or
control (supine) arm based on a closed envelope system.
Procedure
Pre-Operative:
- Obtain informed consent of 64 patients prior to surgery
- Randomize patients to the experimental (15-degree RTP) arm or the control (supine
position) arm.
- 32 patients will receive FESS while in the 15-degree RTP position
- 32 patients will receive FESS while in the standard supine (0-degree) position
- Pre-existing health conditions, current medication and patient demographics (age, sex)
will be recorded
- Patients will be instructed to take the standard pre-operative medications used at St.
Paul's Hospital (prednisone and antibiotics for 1 week).
Intra-operative:
- Patients will initially be placed in a 0-degree supine position, where blood pressure
and pulse rate will be recorded.
- All patients will undergo total intravenous anesthesia, with a prescribed infusion
administered by the residing anesthetist. Anesthesia infusions will be documented and
recorded.
- The Principal Investigator or one of his designates will electronically calibrate the
operating table to bring patients in the experimental arm of the study to the 15-degree
RTP. Those in the control arm will remain in the supine position.
- Primary Outcome Measures:
- MAP, pulse rate and endoscopic field view will be recorded every 15 minutes
intra-operatively.
- Once the procedure is complete, total time of surgery and total estimated blood
loss will be recorded.
- Blood loss per minute will be calculated using total blood loss divided by total
operating time.
Aim 1: To determine the effect of 15-degree RTP on total blood loss, time of surgery and
endoscopic surgical field view when compared with patients in the supine position, during
FESS.
Primary outcome measures will be documented at periodic intervals intra-operatively and at
the completion of surgery. The Principal Investigator or one of his designates will record
MAP, pulse rate and endoscopic surgical field score every 15 minutes from the start of
surgery. Documentation of MAP, pulse rate, and endoscopic surgical field score at periodic
intervals is not standard practice during surgery and it will only be done on study patient
cases. Once the procedure is completed, total blood loss and time of surgery will be
recorded. The total amount of blood lost will be calculated from the suction bottle and
measured in milliliters after surgery. This will be confirmed by the circulating nurse and
the anesthetist. Total time of surgery will be recorded in minutes, by the circulating nurse
and the anesthetist. In certain circumstances the operation may be extended due to
unexpected complications, therefore total blood loss may increase due to prolonged surgery.
To determine blood loss per minute (mL/min), total estimated blood loss will be divided by
time of surgery. Ko et al (2008) previously calculated blood loss per minute with the above
formula in their analysis of the role of RTP during endoscopic sinus surgery.
The Boezaart intra-operative surgical field scale will be used to grade the level of
bleeding during surgery. This 0 to 5-point scale will be used to outline the amount of
suction required to rid the area of blood disrupting vision. A score of 0 is given for an
area with no bleeding, 1 for slight bleeding with no suction required, 2 for slight bleeding
requiring suction, 3 for moderate bleeding which improves for several seconds once suction
has occurred, 4 for moderate bleeding which restarts directly after suctioning and 5 for
severe bleeding which occurs faster then can be removed (12).
Data Collection and Statistical Analysis
Discussion with a statistician indicated that based on a previous study10, a population size
of 64 patients would be needed to achieve a power rating of 80%. Both the experimental and
control arms each will have 32 patients enrolled. To determine the sample size, a confidence
interval of 95% was utilized to create a responsive range of double the standard deviation.
In consideration of the location and vascularity of the paranasal sinuses, a Boezaart score
of 3 is expected during surgery. Clinically significant change in intra-operative bleeding
will be defined as a change in Boezaart scoring by 20%, or one point in relation to the
scale. All data collected for this study will be gathered in a password protected Microsoft
Excel spreadsheet file. Each patient will be assigned unique identification allowing for no
patient data to be recorded. The Microsoft Excel database will include:
- Age
- Sex
- Pre-existing health conditions
- Current medications
- Lund-Kennedy CT score
- CRS with or without polyposis
- Primary or revision surgery
- Anesthesia infusion
- Surgical position (15-degree RTP or Supine)
- MAP (15 minute intervals)
- Pulse rate (15 minute intervals)
- Endoscopic surgical field scores (15 minute intervals)
- Intra-operative complications
- Microdebrider usage
- Total blood loss
- Total time of surgery
Risks No adverse risks are expected from placing patients in the experimental 15-degree
reverse trendelenburg position. Patient care will not be compromised at any time during
surgery. Patients will be able to withdraw from the study at any stage without affecting the
quality of the medical care they receive.
Difficulties and Limitations
Aim 1: No difficulties are expected. Standard practice during FESS at the St. Paul's Sinus
Centre is to document total time of surgery and blood loss on anesthetist and nurse progress
notes, and post-operative surgical reports. For best results, we have included periodic
measurement of MAP, pulse rate and endoscopic surgical field view at 15-minute intervals
intra-operatively. Unexpected or sudden adverse events during surgery may hinder periodic
assessment of our primary outcome measures, as priority will be given to patient safety.
