Clinical Trial Details
— Status: Active, not recruiting
Administrative data
| NCT number |
NCT02738788 |
| Other study ID # |
IRB 11705 |
| Secondary ID |
|
| Status |
Active, not recruiting |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
May 2015 |
| Est. completion date |
July 31, 2025 |
Study information
| Verified date |
February 2024 |
| Source |
Tufts Medical Center |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational
|
Clinical Trial Summary
The goal of this study is to track the intraoperative changes that occur in the airways of
patients undergoing 1) laparoscopic surgeries in the Trendelenburg position, and 2) spinal
surgeries in the prone position, as well as the regression of these changes postoperatively.
These surgeries are known to cause edema and swelling of the soft tissues of the head and
neck, temporarily worsening airway anatomy, but there is little data quantifying these
changes, and no studies have investigated the time course required for the airway to return
to its baseline after extubation. This would be important clinical information given that
airway management is always a major concern perioperatively. The investigators will test
hypotheses by evaluating patients' airways preoperatively, immediately post-extubation, and
at regular intervals thereafter using the Modified Mallampati Score class (MMS), in which a
patient's airway is scored from class 1 to 4 (in which 4 indicates the highest likelihood of
a difficult intubation) based on the visibility of the soft palate, uvula, and faucial
pillars inside the oral cavity.
Description:
Background: One of the primary methods to assess airway dimension changes is the Modified
Mallampati Score (MMS). MMS has been a valuable tool in assessing difficulty of intubation in
previous studies as it is a simple, reproducible, and reliable preoperative and preanesthetic
assessment of oral volume. MMS is evaluated by asking the patient to open their mouth and
protrude their tongue without phonation. A score on a scale of 1-4 is assigned based on
identifiable intraoral anatomic structures. MMS scores of 3 and 4 are strongly associated
with difficult laryngoscopy and intubation.
Extensive observational research in the obstetric population has demonstrated that airway
changes, including increasing MMS and decreasing oropharyngeal volume, occur during labor. It
has been found that 63% of parturients experienced an increase in MMS over the course of
their labor, with the fraction of patients scoring 3 or 4 peaking at 51.7%, compared with
only 10.3% early in labor. Notably, of those patients that reached a class 4, 21% remained at
that classification 48 hours postpartum. It has been found that 18% of patients whose airway
class worsened during labor had not returned to their prelabor class 36-48 hours after
delivery.
These obstetric findings have prompted a limited number of studies investigating airway
changes in patients undergoing surgical procedures. This study will focus on surgeries in the
prone and Trendelenburg positions, as they would intuitively predispose patients to edema and
fluid retention in the head and neck. MMS increased in 78% of patients, with 29% increasing
by two or more classes in patients undergoing lumbar spine surgery in the prone position.
Furthermore, although laparoscopic surgery has been shown to increase lung and chest wall
mechanical impedance, which leads to increases in abdominal and intrathoracic pressure, as
well as an increase in central venous pressure with subsequent increases in intraocular
pressure, no studies have been performed to specifically track resultant airway changes.
Lastly, to investigators' knowledge no studies have investigated the postoperative resolution
of airway changes after either type of procedure.
Rationale: There is evidence, both investigational and anecdotal, that airway changes may
occur during certain surgeries or procedures, and that patient positioning may play a large
role in precipitating them. However, research on this phenomenon in the surgical population,
unlike the obstetric population, is sparse. Similarly, investigations into the time required
for airway changes to regress back to baseline has been included in a number of obstetric
airway studies, but not in any surgical ones. Lastly, it has been suggested that other
surgical factors, such as fluid balance or procedure duration, may alter the degree of airway
changes, but results from the few recent studies on the topic have been unclear. Thus, this
study seeks to further investigate the influence of prone and Trendelenburg positioning, as
well as surgical variables, on perioperative airway changes, and quantify the time required
for patients' airways to return to their preoperative state.
Based on clinical observation, the primary hypothesis is that there will be a significant
difference between mean scoring class change between 2 study groups from preoperative
baseline to initial postoperative assessment. Investigators hypothesize that T-burg surgery
patients will have a mean change of 2 classes compared to a mean change of only one class for
prone spine surgery patients.
The secondary hypothesis is that airway changes occurring in patients undergoing prone
procedures will resolve significantly sooner than (3 - 4 hours) than those of patients
undergoing Trendelenburg surgeries (> 4 hours).
Thirdly investigators will investigate the effects of demographic, physiological, and
surgical & anesthetic variables on postoperative MMS changes and their resolution.
