Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT04566419 |
| Other study ID # |
3228 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
October 1, 2020 |
| Est. completion date |
June 1, 2022 |
Study information
| Verified date |
May 2021 |
| Source |
Fondazione Policlinico Universitario Agostino Gemelli IRCCS |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
The primary aim of this study is to assess the efficacy of post-operatory HFNC in reducing
the incidence of hypoxemia after gynecological oncology surgery, compared to the standard
application of O2 through a Venturi mask; The secondary objectives are to investigate the
occurrence and entity of lung atelectasis, to evaluate diaphragmatic function and respiratory
discomfort, and to evaluate the incidence of respiratory complications after seven days in
the two groups.
Patients will be randomized into two groups: HFNC and Control. The patients will be studied
with preoperative lung and diaphragmatic ultrasound. Standard general anesthesia will be
administered in the two groups. Ultrasound will be performed at arrival in the recovery room
(RR) and before discharge from the RR. In the HFNC group, high-flow O2 will be administered;
in the control group standard O2 therapy with Venturi mask will be administered.
Arterial blood gas analysis upon arrival in the RR and after two hours of O2 therapy in both
groups will be checked.
The incidence of post-operative respiratory complications will be monitored in the seven days
following surgery.
Description:
Post-operative hypoxemia presents in 10-50% of patients undergoing surgery, and it is
associated to unfavourable prognosis. Anesthesia-induced paralysis, the use of high oxygen
concentrations (O2) and inadequate level of positive end expiratory pressure (PEEP),
capnoperitoneum, Trendelenburg position, prolonged duration of surgery, contribute to
pulmonary atelectasis, which are the principal cause of postoperative hypoxemia.
The use of high flow nasal cannulas (HFNC) has been recently studied in the treatment of
hypoxemic patients in intensive care unit and in the immediate post-operatory period after
abdominal and cardio-thoracic surgery. The role of post-operative HFNC in patients undergoing
major gynecological oncology surgery has yet to be assessed.
Lung ultrasound is a safe and accurate bedside tool that allows to investigate pulmonary
aeration and atelectasis developement. Diaphragmatic ultrasound is a recent bedside technique
useful to assess diaphragm performance.
The principal aim of this study is to assess the efficacy of post-operatory HFNC in reducing
the incidence of hypoxemia after gynecological oncology surgery, compared to the standard
application of O2 through the Venturi mask. The secondary objectives are to investigate the
occurrence and entity of lung atelectasis, to evaluate diaphragmatic function and respiratory
discomfort, and to evaluate the incidence of respiratory complications after seven days in
the two groups.
Study Design and Length:
this is an interventional, prospective, randomized (with standard and experimental groups)
monocentric study. The study will be 12-months in length and it will be carried out in the
operating rooms of the 6° floor of the IRCCS Fondazione Policlinico Universitario Agostino
Gemelli.
Materials and Methods:
The patients eligible for recruitment will be randomized with a computerized system and will
be included in wither the HFNC or C group.
Upon arrival in the operating room lung and diaphragmatic ultrasound will be performed
according to the international recommendations of Point of Care. A SonoSite ultrasound with
Convex probe, with abdominal presetting and depth set at 9-12 cm, will be used. The
ultrasound probe will be positioned between the ribs with the marker facing cranially and
position perpendicular to the thoracic cage, oriented along the longitudinal axis of the
patient. The image generated this way will show the superior rib on the left the screen and
the inferior rib on the right of the screen, both represented by acoustic shadowing. The
pleural line will appear between the costal shadows as a slightly curved and eco-reflective
line. In the healthy lung, it is possible to appreciate pleural "sliding" generated by the
movements of the visceral pleura against the parietal pleura during each breath. This
movement will be more pronounced along the lung bases and more blurred at the apices.
Horizontal lines at regular intervals below the pleura that may be appreciated represent
reverberation artefacts that are defined as "A lines." On the other hand, the "B lines," that
are also know as "comets" are artefacts produced by the interface of the normally aerated
lung parenchyma with higher-density areas. These will present as vertical lines that start
from the pleura and develop up to the end of the image, covering the A lines and consensual
to respiratory movements. Twelve images will be acquired, one for each thoracic section
obtained through the following method: for each hemithorax, anterior, posterior and lateral
portions will be recognized relative to the anterior and posterior axillary lines,
respectively. Each section will be further subdivided into superior and inferior by the
intermammillary line. The posterior images will be acquired with the patient lying in lateral
decubitus. A score ranging from 0 to 3 according to Monastesse criteria will be assigned to
each of the 12 quadrants. For each quadrant the worst (higher) score will be considered,
indicating more severe aeration loss. Individual scores will be added to calculate the
cumulative lung ultrasound (LUS) score (0-36).
0: Normal aeration = visualization of pleural sliding and A lines parallel to the pleura with
< 3B lines.1: Mild loss of aeration = ≥3 B lines or multiple subpleural consolidations
separated by normal pleura. 2: Moderate loss of aeration = multiple and coalescent B lines of
multiple subpleural consolidations separated by thickened or irregular pleura. 3. Severe loss
of aeration = parenchymal consolidations or multiple subpleural consolidations greater than
1×2 cm in dimensions.
For diaphragmatic ultrasound a linear high frequency probe will be used. The operator
identifies the caudal border of the costophrenic sinus as the zone of transition from the
artefactual representation of the aerated lung to the visualization of the diaphragm and
liver on the right side. The diaphragm will be identified by the two hyperechoic lines of
pleural and peritoneal membranes. In M-mode, both the respiratory phases are represented in
the same frame. The diaphragm thickness at end-inspiration (TEI), at end-expiration (TEE)
will be measured and the thickening fraction (TF) will be calculated using the formula TF =
(TEI - TEE)/TEE.
The clinical and respiratory parameters from the patients' medical records will also be
reported.
A venous access will be placed, according to normal clinical practice. The use of neuro-axial
blocks (spinal or epidural), as well as the placement of a central venous catheter, arterial
catheter, a second large bore venous access, will be left to the judgement of the anesthesist
in charge of the patient. The induction of general anesthesia will follow a preoxygenation
with inspired oxygen fraction (FiO2) =1 for three minutes. The intraoperative mechanical
ventilation settings will be standardized, with tidal volume set at 8ml/kg of predicted body
weight, PEEP 5 cmH2O, respiratory frequency set to maintain PaCO2 within physiological
limits, I:E ratio of 1:2. In case of intraoperative arterial desaturation (SpO2 < 95%)
different techniques will be adopted in the following order: recruitment maneuvers, increase
in PEEP, and increase in FiO2.
After awakening from general anesthesia the patients will be moved to the RR where standard
multiparametric monitoring will be started, an arterial blood sample will be drawn for blood
gas analysis and a second lung and diaphragmatic ultrasound will be performed following the
same criteria already listed above. Respiratory rate and a Visual Analogue Scale (VAS) for
discomfort and dyspnoea will be filled out.
At this point, the patients selected for the C group will undergo conventional O2-therapy
Venturi mask. In the patients belonging to the HFNC group, high flow O2 (60 lt/min) will be
administered through the use of nasal cannulas with the Opti-Flow circuit. In both groups the
starting FiO2 will be 21% and will be increased of necessary to obtain a SpO2>92. After two
hours of therapy a new arterial blood gas analysis, a third lung-diaphragmatic ultrasound,
respiratory rate, a Visual Analogue Scale (VAS) for discomfort and dyspnoea will be noted,
before the patients are transferred to the ward.
On the seventh day after surgery all of the eventual episodes that may be classified as
postoperative pulmonary complications (PPC) will be recorded (hypoxemia, pleural effusion,
lung edema, pulmonary embolism, pneumonia, acute respiratory distress syndrome (ARDS),
bronchospasm, lung aspiration, pneumothorax).
Population of the study
Statistical Considerations Sample Dimension The literature indicates that roughly 50% of
patients, treated with O2 therapy, develops hypoxemia one hour from extubation. Assuming that
in the experimental branch (arm) that percentage is 15%, considering a strength of 90% and an
alpha =0.05, a sample size of 66 patients will be obtained (33 per branch), at which a 20% of
dropout will be added to reach the final sample size of N = 80 patients (40 per arm).
Data Analysis The sample will be described in its clinical and demographic characteristics
through the techniques of descriptive statistics. In particular, quantitative variables will
be represented though the following measurements: minimum, maximus, range, mean and standard
deviation, or median and interquartile range. Qualitative variables will be represented
through absolute frequencies and percentages. The normality of continuous variables will be
validated through the Kolmogorov-Smirnov test. The primary aim will be reached comparing the
two proportions through the Chi-squared test, while the change in Pa/FiO2 at the different
time points, among the two groups of patients will be assessed by the Student's t-test. The
secondary objective of comparing the incidence of PPC after seven days in the two branches
will be also attained through the Chi-squared test. The p-value<0.05 indicates statistical
significance. All of the statistical analysis will be done with SPSS 25.
