An observational study in Malocclusion, Maxillofacial Injuries and Orthodontics, sponsored by State Budgetary Healthcare Institution, National Medical Surgical Center N.A. N.I. Pirogov, Ministry of Health of Russia. Enrolling by invitation at 1 site in Russian Federation. Open to participants aged 18 Years to 40 Years. Per ClinicalTrials.gov, last updated 2023-05-31.
Sponsored by State Budgetary Healthcare Institution, National Medical Surgical Center N.A. N.I. Pirogov, Ministry of Health of Russia · Observational
It is very important to decrease the bleeding during bimaxillary osteotomy in order to increase the visibility of the surgical site. Our primary goal is to investigate the predictive value of pre- and perioperative factors, including controlled hypotension, on visibility of surgical site during bimaxillary osteotomy.
100 patients undergoing bimaxillary osteotomy under general anesthesia will be included into this prospective cohort study.
There will be two episodes of controlled hypotension for upper and lower jaw respectively. Hypotension will be induced and sustained according to the same procedure as described here. Controlled hypotension will be induced (intravenous administration of nitroglycerin 2-10 µg/kg/min) 15 minutes prior to the start of mucosal detachment, and will be sustained for the osteotomy stage. The surgeon will evaluate the surgical field quality (in terms of bleeding) according to Modena Bleeding Score (MBS), with scores 1-2 being satisfactory to proceed with the osteotomy. The following arterial pressure correction (proceeding with controlled hypotension or returning to normotension) will depend on the bleeding in the surgical field and the monitoring of cerebral oxygen saturation carried out using near-infrared spectroscopy (NIRS) . The lowest targeted arterial pressure in order to have a clear surgical field will be 55 mmHg. However when the cerebral oxygen saturation decreases by 20% compared with the baseline at any arterial pressure level intervention would be carried out by Norepinephrine (intravenous, individual dosage for each patient - as judged by the anesthesiologist). Arterial blood samples will be taken at 3 time points (at the start of the surgery, during controlled hypotension phase, after extubation) for arterial gas analysis. Two blood samples will be taken to measure (prior to surgery and immediately after surgery) neuron-specific enolase (NSE), cystatin c and troponin I levels. The general condition, operation, anesthesia and hospitalization related data of the patients will be recorded. Cognitive function will be evaluated within 3 days before surgery and 2 days and 1 month after surgery.
323 studies on the registry are indexed under Malocclusion; 85 are open to participants now.
This study's planned enrollment of 100 is above the median of 63 across 74 observational studies indexed under Malocclusion.
Browse Malocclusion studies →State Budgetary Healthcare Institution, National Medical Surgical Center N.A. N.I. Pirogov, Ministry of Health of Russia is the lead sponsor of 14 studies on the registry; 3 are open to participants now.
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patients undergoing bimaxillary osteotomy under general anesthesia
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Drug: Nitroglycerin solution · Device: monitoring of cerebral oxygen saturation
Controlled hypotension will be induced (intravenous administration of nitroglycerin 2-10 µg/kg/min) 15 minutes prior to the start of mucosal detachment, and will be sustained for the osteotomy stage.
NIRS-based monitoring of rSO2 has unique advantages: directly or indirectly detecting physiological changes and metabolic processes, it is easy to realize, and involves simple procedures.
Also known as: NIRS
Visibility of surgical site
Surgical site will be rated according to Modena Bleeding Score (MBS) by the same surgeon in terms of bleeding during osteotomy. The MBS goes from Grade 1 - no bleeding to Grade 5 - bleeding that prevents every surgical procedure except those dedicated to bleeding control.
Time frame: during osteotomy, up to 90 minutes
Proportion of patients with cerebral desaturation
Proportion of patients with decrease in cerebral oxygen saturation decreased by 20% compared with the baseline for 300 seconds without improvement
Time frame: during osteotomy, up to 90 minutes
changes in the values of mean arterial pressure
Changes in mean arterial pressure (MAP) values before and during controlled hypotension phase will be registered. MAP calculated as follows: MАP = Diastolic blood pressure + ((Systolic blood pressure - Diastolic blood pressure) / 3).
Time frame: during the whole surgery (from start to finish - the timing stated in the surgery protocol)
Changes in neuron-specific enolase (NSE) concentration
NSE is released from neurons during injury and it's high blood concentration is associated with ischemic brain injury. Level of NSE will be measured in blood samples taken during surgery. Increase of NSE level suggests brain ischemia.
Time frame: 3 time-points during the surgery - immediately after anesthesia induction, at the time of controlled hypotension (5 minutes after induction of controlled hypotension, i.e. nitroglycerin i.v. administration), immediately after extubation
Intraoperative blood loss
Total volume of blood loss during the time of surgery, calculated using direct volumetric measurement.
Time frame: during the whole surgery (from start to finish - the timing stated in the surgery protocol)
Cognitive status change
Cognitive function will be evaluated by means of Mini Mental State Examination (MMSE), which is a 30-point test, validated and commonly used to measure cognitive impairment. Any score of 24 or more (out of 30) indicates a normal cognition. Below this, scores can indicate severe (≤9 points), moderate (10-18 points) or mild (19-23 points) cognitive impairment.
Time frame: within 3 days before operation, 2 days after surgery, 1 month after surgery
Changes in cystatin C concentration
Cystatin C is a well investigated biomarker with clear advantages over serum creatinine in patients with extremes in muscle mass, weight, age, and other areas where estimating equations using creatinine have well documented limitations. Increase of cystatin C level suggests kidney impairment.
Time frame: at the start of the surgery, during controlled hypotension phase, immediately after extubation
Change in Troponin I concentration
The test can be used to aid in diagnosing myocardial infarction.
Time frame: at the start of the surgery, during controlled hypotension phase, immediately after extubation
Plan to share: Yes
Supporting information: Clinical study report
Time frame: 6 months after completion of the study
Access criteria: upon the request
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State Budgetary Healthcare Institution, National Medical Surgical Center N.A. N.I. Pirogov, Ministry of Health of Russia