Ignite Creation Date:
2024-05-06 @ 3:51 PM
Last Modification Date:
2024-10-26 @ 1:59 PM
Study NCT ID:
NCT04788732
Status:
UNKNOWN
Last Update Posted:
2021-03-09
First Post:
2021-03-01
Brief Title:
Heart Rate Variability to Quantify General Anesthesia Depth
Sponsor:
University of Sao Paulo
Organization:
University of Sao Paulo
Study Overview
Official Title:
Heart Rate Variability as Tool for Quantification of General Anesthesia Depth in Patients
Status:
UNKNOWN
Status Verified Date:
2021-03
Last Known Status:
RECRUITING
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
Brief Summary:
The shortage of anesthetic agents can lead to intraoperative awareness while overdosing can trigger severe intra and postoperative problems Therefore monitoring anesthesias depth DoA Depth of Anesthesia is a crucial but still challenging task Although some commercial monitors are based on electroencephalogram EEG designed to quantify DoA their use in clinical practice has limitations On the other hand heart rate variability HRV has valuable information about physiological states both from the heart and the organism Classical indices derived from HRV have been shown to be able to differentiate the different stages of anesthesia In this study it is proposed to create a model to monitor DoA combining several HRV indices Patients will be divided into three groups according to the type of anesthesia to which they will be submitted inhalation total or balanced intravenous and will have the electrocardiogram recorded during the entire surgical procedure Various HRV indices will be calculated and machine learning techniques will be used to combine and identify the most relevant index to compose a score that reliably represents DoA Several commercial devices have been developed to monitor the level of consciousness during anesthesia Among the most popular tools are included Narcotrend TM MonitorTechnik Bad Bramstedt Germany the M-Entropy TM GE Healthcare Helsinki Finland Nindex SA Controls Montevideo Uruguay and the Bi-Spectral Index BIS TM Medtronic-Covidien Dublin Ireland In this study BIS or Nindex will also be monitored during the entire period that the patients remain anesthetized and will later be used to compose the DoA score based on HRV As a result a computer program will be created to monitor DoA in real-time
Detailed Description:
Anesthesia is a state of reversible unconsciousness induced by one or more pharmacological agents The three main anesthesia components are analgesia pain relief amnesia memory loss and immobilization including autonomic reflexes inhibition for harmful stimuli1 Drugs used to induce anesthesia in general have different effects on each of these three components mentioned above
Anesthesia depth assessment DoA from English Depth of Anesthesia is essential for anesthetic practice The DoA depends on two opposing factors the amount of anesthetic agent administered to the patient and the stimuli produced during surgery increasing the level of awareness and the patients nociception The ideal level d the DoA involves the guaranteed unconsciousness and anti-nociception adequate during surgery without compromise the functions of vital organs In other words one of the main challenges for anesthetists is to identify the appropriate amount of anesthetic to be administered to avoid the unwanted effects of anesthetic shortages leading for example to intraoperative awareness or anesthetic overdose which can cause severe problems during intra and postoperative periods 2 Before using muscle relaxants the appropriate level of DoA could be monitored by the absence of movements to painful stimuli once the surgical incisions lack of movements was a sure sign that the patient was not superficially anesthetized However with the muscle relaxants adoption in the anesthetics protocols other measures to ensure that anesthetic agents concentrations were administered properly were necessary
Becoming conscious during surgery is a major concern for patients and anesthesiologists It is estimated that the incidence of consciousness during general anesthesia is low around 004 to 03 However considering the high number of surgical interventions accidental awareness during surgery represents thousands of cases worldwide Therefore despite being an old problem awareness during anesthesia is still a very relevant issue in public health
DoA inefficient may also lead to an imbalance nociception x anti-nociception intraoperatively even without patient conscious pain Nociceptive stimuli can substantially affect the physiological state inducing for example tachycardia hypertension nausea fainting and therefore negatively influencing patients postoperative period 1 Thus careful and efficient monitoring of DoA is the key to minimizing both the possibility of accidental awareness in surgeries and the overdose of anesthetic agents 3 However despite the importance of monitoring d the DoA it is not easy to quantify this parameter during general anesthesia and several approaches have been proposed to accomplish this task
Quantification of DoA
The anesthetic depth could be identified by monitoring the sympathetic activity of the patient However many anesthetics substantially alter autonomic activity both sympathetic and parasympathetic The observation of autonomic responses such as sweating tear formation hypertension tachycardia and pupil dilation are also important indicators of adequate unconsciousness levels However these signals cannot guide the anesthetist considering that the patient cannot react due to neuromuscular blockade 3 On the other hand some authors suggest monitoring the concentration of inspired and expired anesthetic gases as markers of DoA4 However to date there is no standardized and universally accepted method for quantifying DoA and the anesthesiologists experience is still the most important and effective factor in determining DoA
DoAs monitoring techniques have advanced considerably in recent years The nature of changes in electroencephalographic patterns during the stages of anesthesia was studied in detail opening up possibilities for monitoring DoA by identifying electroencephalogram EEG patterns with crucial clinical significance for anesthesia5 The use of EEG devices made monitoring of DoA potentially easier and was recommended by NIH - Care Excellence
Although the progress brought by EEG-based monitors to anesthetic practice is indisputable they still have significant limitations 1 the algorithms created to derive a single DoA index from the EEG are exclusive owned by their creators for each device 2 The EEG obtained in these devices is limited exclusively to the activity of the frontal lobe lacking the representation of deeper subcortical structures 3 EEG is recognized for being highly sensitive to a variety of sources of interference during monitoring 4 it is high cost restricts the availability of such equipment Several monitors have prices ranging from 4687 to 10285 for the initial purchase followed by the acquisition of single-use sensors ranging from 056 to 1408 3 Also recent studies have pointed to substantial divergences between the most common commercial displays at DoA making the application of these electronic devices still controversial and not universally recommended 4 Specific limitations to the use of BIS such as the inconsistency of this index in some situations have also been reported 6 BISs particular challenge involves the administration of ketamine nitric oxide and xenon which do not produce the typical EEG patterns observed during general anesthesia with other anesthetic agents Besides as the BIS was created based on a database of volunteers under specific conditions it must be revalidated whenever used with a new drug or even a unique patient population whose characteristics differ from the original population database data7
Anesthesia depth assessment DoA from English Depth of Anesthesia is essential for anesthetic practice The DoA depends on two opposing factors the amount of anesthetic agent administered to the patient and the stimuli produced during surgery increasing the level of awareness and the patients nociception The ideal level d the DoA involves the guaranteed unconsciousness and anti-nociception adequate during surgery without compromise the functions of vital organs In other words one of the main challenges for anesthetists is to identify the appropriate amount of anesthetic to be administered to avoid the unwanted effects of anesthetic shortages leading for example to intraoperative awareness or anesthetic overdose which can cause severe problems during intra and postoperative periods 2 Before using muscle relaxants the appropriate level of DoA could be monitored by the absence of movements to painful stimuli once the surgical incisions lack of movements was a sure sign that the patient was not superficially anesthetized However with the muscle relaxants adoption in the anesthetics protocols other measures to ensure that anesthetic agents concentrations were administered properly were necessary
Becoming conscious during surgery is a major concern for patients and anesthesiologists It is estimated that the incidence of consciousness during general anesthesia is low around 004 to 03 However considering the high number of surgical interventions accidental awareness during surgery represents thousands of cases worldwide Therefore despite being an old problem awareness during anesthesia is still a very relevant issue in public health
DoA inefficient may also lead to an imbalance nociception x anti-nociception intraoperatively even without patient conscious pain Nociceptive stimuli can substantially affect the physiological state inducing for example tachycardia hypertension nausea fainting and therefore negatively influencing patients postoperative period 1 Thus careful and efficient monitoring of DoA is the key to minimizing both the possibility of accidental awareness in surgeries and the overdose of anesthetic agents 3 However despite the importance of monitoring d the DoA it is not easy to quantify this parameter during general anesthesia and several approaches have been proposed to accomplish this task
Quantification of DoA
The anesthetic depth could be identified by monitoring the sympathetic activity of the patient However many anesthetics substantially alter autonomic activity both sympathetic and parasympathetic The observation of autonomic responses such as sweating tear formation hypertension tachycardia and pupil dilation are also important indicators of adequate unconsciousness levels However these signals cannot guide the anesthetist considering that the patient cannot react due to neuromuscular blockade 3 On the other hand some authors suggest monitoring the concentration of inspired and expired anesthetic gases as markers of DoA4 However to date there is no standardized and universally accepted method for quantifying DoA and the anesthesiologists experience is still the most important and effective factor in determining DoA
DoAs monitoring techniques have advanced considerably in recent years The nature of changes in electroencephalographic patterns during the stages of anesthesia was studied in detail opening up possibilities for monitoring DoA by identifying electroencephalogram EEG patterns with crucial clinical significance for anesthesia5 The use of EEG devices made monitoring of DoA potentially easier and was recommended by NIH - Care Excellence
Although the progress brought by EEG-based monitors to anesthetic practice is indisputable they still have significant limitations 1 the algorithms created to derive a single DoA index from the EEG are exclusive owned by their creators for each device 2 The EEG obtained in these devices is limited exclusively to the activity of the frontal lobe lacking the representation of deeper subcortical structures 3 EEG is recognized for being highly sensitive to a variety of sources of interference during monitoring 4 it is high cost restricts the availability of such equipment Several monitors have prices ranging from 4687 to 10285 for the initial purchase followed by the acquisition of single-use sensors ranging from 056 to 1408 3 Also recent studies have pointed to substantial divergences between the most common commercial displays at DoA making the application of these electronic devices still controversial and not universally recommended 4 Specific limitations to the use of BIS such as the inconsistency of this index in some situations have also been reported 6 BISs particular challenge involves the administration of ketamine nitric oxide and xenon which do not produce the typical EEG patterns observed during general anesthesia with other anesthetic agents Besides as the BIS was created based on a database of volunteers under specific conditions it must be revalidated whenever used with a new drug or even a unique patient population whose characteristics differ from the original population database data7
Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
False
Is a FDA Regulated Device?:
False
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None