Hypotension on Induction
Conditions
Keywords
Ventricular-Arterial Coupling (VAC), Ea/Ees ratio, Post-induction hypotension (PIH), Risk factors for PIH
Brief summary
Post-induction hypotension (PIH) is a common occurrence during the period from induction of general anesthesia to initiation of incision. PIH has been identified as an independent risk factor for postoperative major complications. Identifying high-risk patients for PIH could potentially help prevent its occurrence. Several risk factors associated with PIH have been identified, including patient conditions and use of specific anesthetic agents. Ventricular-arterial coupling (VAC) is evaluated using the ratio Ea/Ees and represents the interaction between the left ventricle (LV) and the arterial system. It reflects how changes in LV contractility (Ees) and changes in arterial load (Ea) work together to maintain optimal LV performance. A study aims to investigate the relationship between preoperative Ea/Ees ratio and the incidence of PIH (defined as MAP \< 65 mmHg).
Detailed description
Post-induction hypotension (PIH) is a common event due to general anesthesia in patients undergoing surgery. It is described as hypotension occurring during the period from induction of general anesthesia to initiation of incision. A universal definition of intraoperative hypotension is lacking, leading to inconsistent rates of occurrence for PIH. According to Yoshimura et al., PIH occurs in 34% of patients using the mean arterial pressure (MAP) definition of \< 55 mmHg, whereas Maheshwari found PIH in 53% of patients using a MAP definition of \< 65 mmHg. Furthermore, Maheshwari et al. demonstrated that PIH was an independent risk factor for postoperative major complications such as myocardial injury, cerebrovascular events, and acute kidney injury. If high-risk patients for PIH could be identified we might potentially prevent PIH. In a systematic review, Chen et al. pointed out that the risk factors associated with PIH were ASA (American Society of Anesthesiologists) III-V, advanced age, emergency cases, hypovolaemia, long-term use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, use of propofol and high-dose of opioid. This study suggests that PIH may be the result of an interaction between the anesthetic agent and the cardiovascular condition of the patient. Conditions such as moderate-to-severe aortic regurgitation, moderate-to-severe mitral regurgitation, regional wall motion abnormalities, and echocardiography findings (e.g. elevated ratio of peak early diastolic transmitral flow velocity to annular velocity) have been identified as PIH-independent risk factors. End-systolic elastance (Ees) is a measure of the contractile state of the left ventricle (LV). It represents the relationship between LV end-systolic pressure (LVESP) and end-systolic volume (ESV). Effective arterial elastance (Ea) is a measure of the total arterial load on the LV and is calculated as the ratio of LVESP to stroke volume (SV). Ventricular-arterial coupling (VAC), assessed by the ratio Ea/Ees, describes the interaction between the LV and arterial system. VAC reflects the interplay between the changes in LV contractility (Ees) and changes in arterial load (Ea) to maintain optimal LV performance. Aktas et al. analyzed Ea as a predictor of PIH. The results of this study showed that pre-induction Ea had excellent predictability of hypotension. However, Ees values were not determined, thus making it speculative to conclude that pre-induction VAC is impaired in patients with high Ea. There are no studies available that assessed the role of preoperative VAC in predicting PIH. Therefore, we will investigate the relationship between the preoperative Ea/Ees ratio and the incidence of PIH (: hypotension being defined as MAP \< 65 mmHg).
Interventions
None listed
Sponsors
University Medical Center Ho Chi Minh City (UMC)
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Patients ≥ 18 years old. * Patients with ASA (American Society of Anesthesiologists) physical status 1 - 4. * Elective non-cardiac, non-obstetric, and non-gynaecologic surgery * Preoperative transthoracic echocardiography was performed within 48 hours before surgery. The values of Ees and Ea were determined by the method of Chen. * Patients consented to participate in the study. * Patients scheduled for surgery undergoing standard general anesthesia (protocol: see below) with endotracheal intubation. * Patients were hemodynamically stable until the preoperative period.
Exclusion criteria
• Uncorrected congenital heart disease, moderate-to-severe valvular disease or pulmonary hypertension, arrhythmias, anticipated difficult airway, and known allergy to anaesthetic agents.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Incidence of Post-Induction Hypotension | From induction of anesthesia to surgical incision, up to 1 hour | Post-induction hypotension (PIH) was defined according to the protocol criteria and assessed during the interval from induction of anesthesia to surgical incision. The incidence of PIH was calculated as the number of analyzed participants who developed PIH during this interval. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Area Under the Receiver Operating Characteristic Curve for Prediction of Post-Induction Hypotension | From induction of anesthesia to surgical incision, up to 1 hour | Predictive performance for post-induction hypotension (PIH) was evaluated using logistic regression models. Model discrimination was assessed using the area under the receiver operating characteristic curve (AUC). Clinical variables, echocardiographic measurements, and ventriculo-arterial coupling (VAC)-related variables were evaluated for prediction of PIH. Higher AUC values indicate better model discrimination. |
| Fractional New Information Added for Prediction of Post-Induction Hypotension | From induction of anesthesia to surgical incision, up to 1 hour | Incremental predictive value for post-induction hypotension (PIH) was assessed using fractional new information (FNI). FNI was used to quantify the additional predictive information provided by echocardiographic measurements and ventriculo-arterial coupling (VAC)-related variables when added to the clinical prediction model. |
Countries
Vietnam
Contacts
STUDY_DIRECTORKhoi M Le, Assoc.Prof
University Medical Center
Baseline characteristics
| Characteristic | — |
|---|---|
| Age, Categorical <=18 years | 2 Participants |
| Age, Categorical >=65 years | 77 Participants |
| Age, Categorical Between 18 and 65 years | 326 Participants |
| Age, Continuous | 57 years |
| Sex: Female, Male Female | 233 Participants |
| Sex: Female, Male Male | 172 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 425 |
| other Total, other adverse events | 0 / 425 |
| serious Total, serious adverse events | 0 / 425 |
Outcome results
None listed