Dexmedetomidine Improved Oxygenation and Reduced Shunt in One-Lung Ventilation at High-Risk Pediatric Thoracic Surgery

NCT ID: NCT06505772

Last Updated: 2024-07-23

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 78 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2023-03-01
• Study Completion Date: 2024-07-01

Brief Summary

Children with high anesthetic risk who underwent Thoracic surgery with OLV (one lung ventilation) technique during general anesthesia were divided into two groups.

The first is an intravenous injection of dexmedetomidine at a rate of 0.4 micrograms/kg/hour as a continuous intravenous infusion. The second group, the placebo group, injected the second with a normal saline solution, an infusion that will pass through the vein, using blinded, unmarked syringes.

Three arterial blood gas (ABG) samples were taken during surgery at designated times. Circulatory PaO2 values were recorded and the Qs/Qt shunt value was calculated.

Detailed Description

Pediatric specific anatomy and physiology includes small ventricles with low systolic mass and poor ventricular compliance . With decreased peripheral vascular resistance (SVR) . The parasympathetic nervous system is dominant. This explains why HR is delayed compared to changes in MAP and mean blood pressure, is less affected and slower to respond. As each terminal bronchiole opens into a single alveolus and initially forms clusters of clusters, rather than fully developed alveolar clusters, these clusters continue to grow until six to eight years of age to resemble adults. The diaphragm is more horizontal, which reduces its mechanical advantage. Ventilation depends mainly on the diaphragm and the rate of its movements (breathing movements). Higher compliance of the thoracic wall is also seen with increased respiratory work.

Decreased functional residual capacity (FRC) increases pulmonary shunting and leads to atelectasis. One-lung ventilation (OLV) during general anesthesia can improve the surgical field of view, which is often used in thoracic surgery. However, OLV can lead to a mismatch in the ventilation/perfusion ratio (V/Q), leading to increased shunt and pulmonary shunt fraction (Qs/Qt) within the lungs and the occurrence of hypoxia. The ratio between the rate of flow of unoxygenated blood from the pulmonary arteries to the pulmonary veins through the shunt (Qs), and the total rate of blood flow through the lungs (Qt), i.e., the ratio between the unoxygenated blood and the total blood, is known as the pulmonary shunt fraction (Qs/Qt). The FEV1/FVC ratio represents the proportion of the total vital capacity that can be exhaled in the first second of forced expiration, whereas FEV1 indicates "Force Expiratory Volume in 1 second" and FVC indicates "Forced Vital Capacity".

Hypoventilation-induced vasoconstriction (HPV) is the body's primary compensatory mechanism against pulmonary constriction, which is to divert pulmonary perfusion blood from the nonventilated area to the ventilated area, thereby reducing pulmonary constriction and improving blood hypoxia . HPV is affected by various factors, including changes in pulmonary pressure, alkalosis, vasodilators, and inhaled anesthetic gases, which have the greatest effect. The study was designed as a two-group, controlled clinical trial using propofol, which is known to have no effect on HPV.

Dexmedetomidine is widely used as an anesthetic adjuvant. It is a highly selective alpha2 adrenergic receptor agonist that directly stimulates peripheral alpha2 receptors to induce vasoconstriction and increase blood pressure, as well as act on central alpha2 receptors to suppress sympathetic excitation, which can dilate blood vessels and lower blood pressure. Alpha adrenal blockade eliminates pulmonary arrhythmias that responded to non-adrenal but not hypoxia . Due to the complex effects of dexmedetomidine on blood circulation, it is difficult to predict its effects on intrapulmonary shunt and hypoventilation-induced vasoconstriction in patients during one-lung ventilation . The hypothesis of our study predicted that dexmedetomidine would improve oxygenation Partial Pressure of Arterial Oxygen (PaO2) and reduce pulmonary shunting during OLV in children.

Conditions

One-Lung Ventilation; Thoracic Surgery

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: QUADRUPLE

Study Groups

The dexmedetomidine group

Dexmedetomidine:

An initial dose of 0.5 mcg/kg of dexmedetomidine will be given over 10 minutes, starting 10 minutes after the initiation of anesthesia infusion.

Following the initial dose, a continuous infusion of dexmedetomidine will be administered at a rate of 0.4 mcg/kg/hour.

The infusion will be stopped before skin closure.

Group Type: EXPERIMENTAL

Dexmedetomidine

Intervention Type: DRUG

Infusion syringes are supplied with a concentration of 0.25 mcg / mL (dexmedetomidine ) either 80 mcg / 20 mL, 200 mcg / 50 mL, or 400 mcg / 100 mL.

For example, it begins with an infusion of 4 ml over 10 minutes and then continues the infusion, depending on the weight of the child, at a rate of 1.6 ml/kg/hour.

All injections will be prepared randomly by a doctor who did not participate in the study, and then placed in unmarked infusion pumps, given to an anesthesiologist (more than 10 years experience in pediatric anesthesia) without knowledge of the infusion content. The randomization process is carried out via sealed envelope technique.

The injections in both groups will be stopped before the skin is closed. Both patients and anesthesiologists blinded the study drug (dexmedetomidine or placebo) by infusion of solution (dexmedetomidine or placebo). Depending on the size in ml, to ensure that there is no bias and blindness to the medical team about what the drug is.

The Placebo group (the control group):

Saline Solution (Placebo):

After the induction of anesthesia, a volume of saline solution equivalent to the volume of dexmedetomidine used in the experimental group will be administered using the same protocol.

Group Type: PLACEBO_COMPARATOR

Normal saline

Intervention Type: DRUG

Normal saline (NS) for intravenous infusion is supplied in pre-filled syringes of 20 ml, 50 ml, and 100 ml. To maintain blinding in this study, NS is handled identically to the study drug, dexmedetomidine. A physician not involved in the study prepares all injections, randomly assigning either NS or dexmedetomidine using a sealed envelope technique. Prepared syringes are then placed in identical, unmarked infusion pumps.

Infusion Protocol:

Anesthesiologists, blinded to the infusion contents, administer the solutions according to the protocol:

For example,Initial Bolus: 4 ml infused over 10 minutes, Maintenance Infusion: Continued at a rate of 1.6 ml/kg/hour, adjusted to the individual patient's weight.

This process ensures both patient and anesthesiologist remain blinded to the treatment arm, minimizing potential bias throughout the study.

Interventions

Dexmedetomidine

Infusion syringes are supplied with a concentration of 0.25 mcg / mL (dexmedetomidine ) either 80 mcg / 20 mL, 200 mcg / 50 mL, or 400 mcg / 100 mL.

For example, it begins with an infusion of 4 ml over 10 minutes and then continues the infusion, depending on the weight of the child, at a rate of 1.6 ml/kg/hour.

All injections will be prepared randomly by a doctor who did not participate in the study, and then placed in unmarked infusion pumps, given to an anesthesiologist (more than 10 years experience in pediatric anesthesia) without knowledge of the infusion content. The randomization process is carried out via sealed envelope technique.

The injections in both groups will be stopped before the skin is closed. Both patients and anesthesiologists blinded the study drug (dexmedetomidine or placebo) by infusion of solution (dexmedetomidine or placebo). Depending on the size in ml, to ensure that there is no bias and blindness to the medical team about what the drug is.

Intervention Type: DRUG

Normal saline

Normal saline (NS) for intravenous infusion is supplied in pre-filled syringes of 20 ml, 50 ml, and 100 ml. To maintain blinding in this study, NS is handled identically to the study drug, dexmedetomidine. A physician not involved in the study prepares all injections, randomly assigning either NS or dexmedetomidine using a sealed envelope technique. Prepared syringes are then placed in identical, unmarked infusion pumps.

Infusion Protocol:

Anesthesiologists, blinded to the infusion contents, administer the solutions according to the protocol:

For example,Initial Bolus: 4 ml infused over 10 minutes, Maintenance Infusion: Continued at a rate of 1.6 ml/kg/hour, adjusted to the individual patient's weight.

This process ensures both patient and anesthesiologist remain blinded to the treatment arm, minimizing potential bias throughout the study.

Intervention Type: DRUG

Other Intervention Names

Precedex; Placebo

Eligibility Criteria

Inclusion Criteria

• children with American Society of Anesthesiologists (ASA) grade III
• FEV1/FVC values less than 80% . FEV1/FVC ratio represents the proportion of the total vital capacity that can be exhaled in the first second of forced expiration, whereas FEV1 indicates "Force Expiratory Volume in 1 second" and FVC indicates "Forced Vital Capacity".
• Qs/Qt ratio greater than 10 .

Exclusion Criteria

• renal failure.
• hepatic dysfunction.
• congenital and valvular cardiac disease.
• neurological illnesses.
• During surgery, individuals who did not achieve complete lung isolation were excluded.
• During surgery, individuals with poor oxygen saturation (SO2 <90%) who did not react to maneuvers and anesthetic procedures to boost saturation were removed.
• During surgery, Participants who had a heart rate of less than 80 beats per minute, did not react to atropine, or required a dosage of inotropic drugs (dopamine) were also removed from the trial.

• Minimum Eligible Age: 4 Years
• Maximum Eligible Age: 6 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Damascus University

OTHER

Sponsor Role: lead

University Children's Hospital

OTHER

Sponsor Role: collaborator

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Faten Rostom, PHD

Role: STUDY_CHAIR

Department of Anesthesiology Faculty of Medicine Damascus University

Locations

University Children's Hospital

Damascus, , Syria

Countries

Syria

References

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Other Identifiers

UDMS-Anesth-02-2024

Identifier Type: -

Identifier Source: org_study_id