The growing number of large volume surgical interventions performed throughout the world paralleled by an increase of aging patient population with a greater prevalence of complex medical comorbidities [1]. High-risk patients, usually classified according to American society of anesthesiologists (asa) physical status classification of III or IV, have important systemic disease, from advanced cardio vascular diseases to chronic obstructive pulmonary diseases or end stage metabolic diseases [1, 2]. These systemic vulnerabilities become a strong determinant of physiological reserve under major invasive procedures like large intra-abdominal, open orthopedic and extensive vascular reconstruction surgeries [2]. This is an increase in the vulnerability of this high-risk subpopulation to major adverse perioperative events, as well as to longer intensive care unit (ICU) stay and higher post-surgical morbidity and mortality rates [3].

In high risk patients, the main mechanism causing postsurgical tissue injury and secondary dysfunction of other organs is systemic occult hypoperfusion [4]. Many different physiological stresses are associated with large surgical procedures, such as the direct myocardial depressive effects of anesthetic drugs, hypotension, surgical retraction and alterations in positive pressure mechanical ventilation, which disrupt normal macrovascular and microvascular regulatory networks [4,5]. Traditional conventional anesthetic methods have used less dynamic monitoring parameters like intermittent non-invasive blood pressure, HR, and central venous pressure [5].

But traditional measures of these indexes are often poor at determining when subtle chronic mismatching occurs between tissue oxygen delivery and metabolic demand [4]. Inside target zones, which are vulnerable to ischemia and growth regulation, such as renal parenchyma and splanchnic vascular beds, regions of profound microvascular ischemia and further cellular damage cascades may have already started by the time there are easily detectable changes in basic standard monitors, including systemic macrovascular changes such as hypotension.

Modern sophisticated anesthesia management has turned towards individualized and goal-directed fluid and hemodynamic therapy to avoid these systemic events of ischemia cascading downstream. Advanced monitoring technology of the continuous stroke volume and cardiac output without surgery or puncture is used routinely during surgery in tailored anesthesia procedures [7,8]. Dynamic assessment of physiological parameters (stroke volume variation (SVV), pulse pressure variation (PPV), absolute cardiac index (CI)) can help the provider of anesthesia, in differentiating between fluid responsiveness, from myocardial contractility failure and peripheral vasodilation anomaly [8].

This accurate real-time (in vivo) physiological phenotyping enables the targeted titration of crystalloid infusion, as well as targeted continuous inotropic infusion and vasoactive drugs for each patient separately and based on their individual physiological needs [7,8]. This dynamic tailoring also avoids fluid overload states, which give rise to tissue oedema and respiratory complications, and importantly maintain appropriate organs perfusion pressures [9].

Though goal-directed fluid therapies are effective in RCTs conducted internationally in a controlled environment, there is limited real-world clinical data on the use of a comprehensive and tailored anesthetic technique in routine clinical care in low-to-middle income healthcare systems [10]. High risk surgical patients often arrive with complicated and non optimised systemic diseases in resource-limited tertiary care settings, such as Pakistan [5]. Meanwhile, due to clinic restrictions, high-end monitoring kits and consumables may not be available and thus evidence of the clinical effects of dynamic anesthetic customization must be built at the local level.

We studied the impact of customized anaesthetic management with a target of maintaining hemo dynamic stability and reducing the potential post-surgical life-threatening complications in the post anaesthetic intensive care unit (PAICU) among high-risk population treated at a newly implemented public tertiary care hospital in Southern Punjab through a prospective, clinical cohort study.

Study Design and Clinical Setting It is a prospective observational cohort study conducted at the Department of Anesthesia, Intensive Care and Pain Management in the Tertiary Care Hospital Nishtar 2 at Nishtar Medical University in Multan, Pakistan. The clinical enrollment process began in March 2025 and lasted for six months. Study protocol was developed and performed in line with the ethical principles of the Declaration of Helsinki and current guidelines for advanced perioperative monitoring. Sample patient selection and inclusion criteria The study population included those adults who were undergoing elective or semi-urgent major open intra-abdominal operations (such as major oncological resections, pancreatectomies, and extensive hepatobiliary surgery), or multi-level orthopedic surgery, or peripheral vascular reconstructive surgery. The following requirements led to inclusion: 1. Patients in the age range of 45-75 years, both male and female. 2. A preexisting American Society of Anesthesiologists (ASA) Physical Status classification class III (severe systemic illness which limits activity) or class IV (incapacitating systemic illness which is a constant threat to life). 3. Expected post-operative admission of at least 48 hours to surgical intensive care unit. All data from the following were regarded as exclusion: 1. Emergency surgery for rupture of aortic aneurysm or for massive hemorrhagic shock. 2. Presence of end stage renal disease already on chronic maintenance hemodialysis. 3. Severe left ventricle EF<25% or uncompensated valvular hear failure. 4. Intraoperative refusal by patient or change of surgery plan. Inpatient Interventions to Use During Anesthetic and Intraoperative Periods Patients were randomly assigned to two parallel clinical management groups determined by the presence of advanced monitoring infrastructure, and the choice of intraoperative protocol made by the attending anesthetic team: • Tailored Anesthesia Group (n = 84): Patients in this group had complete individual goal directed management. The use of an advanced arterial line waveform analysis system (FloTrac/Vigileo monitor or similar advanced monitoring technology) was introduced before induction, along with the standard baseline monitoring. Low dose propofol/etomidate, fentanyl and cisatracurium were carefully titrated to minimize initial myocardial depression. Hemodynamic optimization was conducted in a strictly protocol manner on the basis of the dynamic index (SVV) with fluid boluses (250 mL balanced crystalloid) given exclusively when the SVV was > 12% for more than 5 min. If hypotension remained after an SVV is less than 12 percent, a continuous infusion of norepinephrine was instituted to reach the target mean arterial pressure (MAP) of 65 mmHg or higher. A low-dose of dobutamine was useful for making direct myocardial contractility adjustment when continuous cardiac index was <2.5 L/min/m2. • Conventional Anesthesia Group (n = 84): The group of patients in which the traditional baseline monitoring techniques: continuous electrocardiography, noninvasive or standard invasive blood pressure monitoring, pulse oximetry and capnography were used. General anesthesia was induced and maintained using standard doses of volatile anesthetics and intravenous analgesics used at our institution. The volume of fluids were given according to the standard algorithm of maintenance volume plus blood loss, urine output and CVPR check. Boluses of crystalloids or ephedrine/phenylephrine were administered when hypotension occurred (reactively). • Primary- and secondary-outcome measures The continuous assessment window was from induction of anesthesia to 72 hours, post-operative in intensive care unit. The main results were: 1. Perioperative Hemodynamic Instability: Total number of distinct hypotensive episodes intraoperatively (MAPdrop < 65 mmHg for > 1 minute) and Total intra-operative hypotension (time in minutes that MAPdrop < 65 mmHg for > 1 minute). 2. Overall Post-Surgical ICU Complication Rate: Percentage of patients with one or more major organ system functions problems in the first 72 hours following surgery. Secondary outcomes included: 1. Acute Kidney Injury (AKI): classified using the Kidney Disease: Improving Global Outcomes (KDIGO) criteria based on increase of plasma creatinine from baseline or oliguria within 72 hours. 2. Post-operative Respiratory Complications: As inability to extubate within 12 hours after surgery, acute respiratory distress syndrome (ARDS) or need for re-intubation in the intensive care unit (ICU). 3. Cardiovascular Events: The occurrence of new onset of atrial fibrillation, myocardial ischemia or acute congestive heart failure in the ICU. 4. Length of ICU stay: The length of stay in days in Intensive Care Unit. Statistical Analysis SPSS software 26.0 was used for Data compilation and Statistical Analysis. Normality of continuous data distributions was tested using Shapiro-Wilk test. Normally distributed variables were recorded as mean values ± standard deviation (SD) and statistically compared using the student's independent t-test. Medians with interquartile range (IQR) were reported for values that were not normally distributed and analyzed using the Mann-Whitney U test. Categorical variables are represented as raw data and percentages; differences were calculated by using either the Chi-square test or Fisher's exact test. Statistically significant p values were set a priori at < 0.05.

Demographic and Clinical Baseline Profiles

168 high-risk surgical patients were enrolled and completed the protocol.

Preoperative renal function, age distribution, gender ratio, ASA status distribution were not significantly different between the two treatment groups ensuring clinical comparability (Table 1).

The average baseline demographics and clinical parameters are presented in table.

Table 1 lists the mean baseline demographic and clinical parameters.

Primary Outcomes include Hemodynamics and ICU Complications.

There was a significant intergroup variability with respect to hemodynamic stability during surgery. In the Tailored Anesthesia Group, 21.4 per cent (n = 18) of patients had at least one episode of intraoperative hypotension that required intervention while 46.4 per cent (n = 39) of patients in the Conventional Anesthesia Group also required corrective action (Chi-square = 11.78, p = 0.001).

Additionally, there was a significant decrease in the cumulative duration of systemic hypoperfusion when using tailored protocol. The median total time an intraoperative MAP <65mmHg occurred was 4.5 minutes (IQR, 2.0–8.5 minutes) for the tailored cohort and 14.2 minutes (IQR, 8.0–22.5 minutes) for the conventional management cohort (p < 0.001).

This relative decrease in intraoperative hypoperfusion was related to diminished burden of early complications after surgery and transfer to the intensive care unit (ICU). There was an overall reduction in major complications to 17.9 percent (n = 15) in the Tailored Anesthesia Group versus 36.9 percent (n = 31) in the Conventional Anesthesia Group, statistical significance of which was achieved within 72 hours after surgery (Chi-square = 7.64, p = 0.006).

Organ-Specific Complications: Secondary Outcomes

Analyses by organ showed protection in several organ systems. In groups with tailored anesthesia, post-operative acute kidney injury (AKI) developed in 4 (4,8 per cent) and in conventional anesthesia group 13 (15,5 per cent) patients (p = 0,021).

Pulmonary outcomes were also more favorable for the tailored management group, with prolonged mechanical ventilation or re-intubation (7.1 percent, n = 6) versus 17.9 percent, n = 15), from the conventional group (p = 0.038). There was a significant difference in total surgical ICU stay, with a median of 2.1 days in the tailored anesthesia group and 3.8 days in the conventional group (p = 0.002).

Table 2 shows a comparative summary of the hemodynamic and ICU outcomes.

Complex care is one of the major factors of challenge in the management of high risk surgical patient in the tertiary health care system especially after the surgical procedure [2]. Thre prospective evaluation of effect of customized anesthetic techniques as compared to conventional anesthetic techniques in a large tertiary care teaching center in South Punjab was conducted. Overall, our clinical results show that converting anesthetic choices, according to the individually set anaesthetic goals based on advanced clinical haemodynamics and dynamic titration of haemodynamic parameters, improves haemodynamic stability during the perioperative period and leads to fewer (predefined) serious complications in the intensive care unit (ICU) within 72 hours of surgery.

As presented elsewhere in the international literature on clinical trials, our in-hospital record of decreased number of intraoperative hypotensive events and reduced total hypoperfusion time with a tailored protocol is comparable [7,8]. Traditional monitoring targets are followed in standard anesthesia protocols, thereby resulting in a delay of alerting to the presence of occult systemic hypoperfusion [5].

Tailored anesthesia protocols, on the other hand, make use of variables such as stroke volume variation (SVV) or cardiac index to reflect the fluid responsiveness and cardiac contractility on a continuous basis [8,9]. This enables the anesthesia professional to distinguish between relative hypovolemia, vasodilation, and depression of the heart to make specific decisions on the use of crystalloid, vasopressor, or inotropic responses. This proactive fluid and cardiovascular titration reduces chronically ischemic states in systemically perfused tissue, as well as fluid overload states [9,10].

It's an important finding about the correlation of reduced intraoperative hypotension and reduced rates of post-operative acute kidney injury. The renal parenchyma has been shown to be very sensitive to hypoperfusion related to the operative period, and even brief episodes of relative hypotension (MAP less than 65 mmHg) disrupt renal auto-regulation and result in ischemic acute tubular necrosis [6,11].

We found that in the tailored group the median duration of intraoperative hypotension was 4.5 minutes vs. 14.2 minutes in the conventional group and that the incidence of acute kidney injury was reduced (4.8 percent vs. 15.5 percent). This is in line with studies done by Futier et al., which suggested that use of a goal directed protocol of maintaining systemic perfusion preserves microvascular blood flow in major organ structures and thus reduces the scoring for organ dysfunction post-operatively [5].

We had better respiratory results in the tailored anesthesia group as well. Traditional fluid management strategies often lead to relative fluid overload, leading to pulmonary interstitial edema, poor gas exchange, and delayed extubation/postextubation or rescue mechanical ventilation in the ICU [9].

You could see from the tailored group that there was a functional response; fluid boluses were only given when a functional response was likely – this may have prevented occult hypervolemia [8]. This may indeed account for the dramatic differences in the prolonged mechanical ventilation and re-intubation rates between the tailored cohort and the conventional cohort (7.1 percent vs. 17.9 percent).

This study offers actual-life facts in a Pakistani public health care surroundings, however, with a number of clinical restrictions. First, it is designed as an observational study and randomization may not have been feasible as treatment decisions were based on the immediate availability of the monitoring system and the preferred treatment of the clinical team. Second, our assessment period only covered the first 72 hours after surgery in the intensive care and did not show long-term surgical outcome, 30 day mortalities or long-term organ dysfunction rates.

Continued large-scale, randomized controlled trials are called for to further optimize resource allocation and to standardize adjustment of tailored anesthetic guidelines in the structure of public health in each region.

Finally, overall routine use of customized anesthetic protocol in high-risk patient who underwent major surgery considerably helped to maintain perioperative hemodynamic stability, prevent intraoperative hypoperfusion, and decrease acute kidney injury, respiratory failure and other post-surgical intensive care complications.

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