A Cohort Prospective Study of Predictors Influencing the Quality of Visualization of the Operating Field During Orthognathic Surgery

Sponsor

State Budgetary Healthcare Institution, National Medical Surgical Center N.A. N.I. Pirogov, Ministry of Health of Russia (Other)

Overall Status

Not yet recruiting

CT.gov ID

NCT05814991

Collaborator

(none)

100

Enrollment

Location

37.5

Anticipated Duration (Months)

2.7

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

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.

Condition or Disease	Intervention/Treatment	Phase
Malocclusion Maxillofacial Injuries Orthodontics Hemorrhage	Drug: Nitroglycerin solution Device: monitoring of cerebral oxygen saturation

Detailed Description

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.

Study Design

Study Type:

Observational

Anticipated Enrollment :

100 participants

Observational Model:

Cohort

Time Perspective:

Prospective

Official Title:

A Cohort Prospective Study of Predictors Influencing the Quality of Visualization of the Operating Field During Orthognathic Surgery

Anticipated Study Start Date :

May 2, 2023

Anticipated Primary Completion Date :

Jan 15, 2026

Anticipated Study Completion Date :

Jun 15, 2026

Arms and Interventions

Arm	Intervention/Treatment
Patients undergoing bimaxillary osteotomy under general anesthesia	Drug: Nitroglycerin solution 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. Device: monitoring of cerebral oxygen saturation 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. Other Names: NIRS

Arm

Intervention/Treatment

Patients undergoing bimaxillary osteotomy under general anesthesia

Drug: Nitroglycerin solution

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.

Device: monitoring of cerebral oxygen saturation

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.

Other Names:

NIRS

Outcome Measures

Primary Outcome Measures

Visibility of surgical site [during osteotomy, up to 90 minutes]
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.

Secondary Outcome Measures

Proportion of patients with cerebral desaturation [during osteotomy, up to 90 minutes]
Proportion of patients with decrease in cerebral oxygen saturation decreased by 20% compared with the baseline for 300 seconds without improvement
changes in the values of mean arterial pressure [during the whole surgery (from start to finish - the timing stated in the surgery protocol)]
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).
Changes in neuron-specific enolase (NSE) concentration [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]
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.
Intraoperative blood loss [during the whole surgery (from start to finish - the timing stated in the surgery protocol)]
Total volume of blood loss during the time of surgery, calculated using direct volumetric measurement.
Cognitive status change [within 3 days before operation, 2 days after surgery, 1 month after surgery]
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.
Changes in cystatin C concentration [at the start of the surgery, during controlled hypotension phase, immediately after extubation]
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.
Change in Troponin I concentration [at the start of the surgery, during controlled hypotension phase, immediately after extubation]
The test can be used to aid in diagnosing myocardial infarction.

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years to 40 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

Patients refered for bimaxillary osteotomy under general anesthesia with endotracheal intubation;
Anesthesia risk classes (ASA) I and II;
Written statement of informed consent.

Exclusion Criteria:

Hypertension as a symptom of hypertensive heart disease or endocrine dysfunction;
Patients receiving antihypertensive drugs;
Patients receiving anticoagulant therapy;
Ischemic heart disease;
Cerebrovascular insufficiency;
Severe hypovolemia;
Anemia;
BMI 30 kg/m2 and higher;
Connective tissue disorders;
Pregnancy;
Participation in other clinical studies;
Recent history of substance abuse (recreational drugs, alcohol);
Allergies to drugs used in the study;
Anxiety requiring psychiatrist supervision and pharmacological therapy.