Perioperative Patients With Hemodynamic Instability: Consensus Recommendations of the Anesthesia Patient Safety Foundation

Development and evaluation of an automated phenylephrine delivery system by lower limit control for managing intraoperative hypotension

PURPOSE

In this study, we aimed to develop and evaluate an automated phenylephrine delivery system by lower limit control for the management of intraoperative hypotension, assessing its efficacy in maintaining adequate blood pressure levels.

METHODS

Twenty patients undergoing surgery with anticipated blood pressure fluctuations were enrolled in this study. Patients were randomly assigned to two groups. Noninvasive blood pressure (NIBP) was measured at 2.5-min intervals using an upper arm cuff. In the automated group, phenylephrine administration was governed by an automated system that delivered bolus doses and adjusted the continuous infusion rate when mean blood pressure (MBP) dropped below 65 mmHg. In the manual group, phenylephrine administration was initiated by the attending anesthesiologist under the same MBP threshold. Propofol, remifentanil, and rocuronium were administered via the automated delivery system for total intravenous anesthesia, to minimize hemodynamic variability between groups. The primary end point was the percentage of time during which MBP remained above 65 mmHg and systolic blood pressure below 140 mmHg, measured from the initiation to the cessation of intravenous anesthesia and assessed using a non-inferiority test.

RESULTS

The automated group adequately maintained blood pressure within the target range for 84.53% of the time, compared to 72.45% in the manual group, confirming statistical non-inferiority (p < 0.001).

CONCLUSION

This system effectively managed intraoperative hypotension using intermittent NIBP measurements, which are more feasible in clinical practice. Despite relying on less frequent and lower-resolution blood pressure data, it demonstrated efficacy comparable to anesthesiologist-led management, indicating its potential for broader clinical application.

Effect of neurally adjusted ventilator assist versus pressure support ventilation on asynchronies and cardiac function in pediatric liver transplantation

In pediatric liver recipients perioperative factors may affect respiratory and cardiac function, and prolong mechanical ventilation during post-operative period. The use of NAVA can improve the interaction between the patient and the ventilator from both a respiratory and cardiac perspective. The objective of this study is to evaluate the synchronization between the patient and the ventilator, as well as cardiac function, during the application of neurally adjusted ventilatory assist (NAVA) and pressure support ventilation (PSV) in pediatric liver transplant recipients. This is a single-center, prospective, randomized, physiological cross-over controlled trial conducted between 2021 and 2022. Children (1 month-10 years old) who underwent liver transplantation were admitted to the pediatric intensive care unit. Patients were randomised to one of two crossover sequences of ventilation trials of 40 min each (PSV/NAVA/PSV or NAVA/PSV/NAVA). Cardiac function was studied by echocardiogram. Twenty-four patients were enrolled and 21 completed the study. Primary outcomes were variation of asynchrony index (AI) and tricuspid annular plane systolic excursion (TAPSE) during the two ventilation modes. Secondary outcomes were patient-ventilator interaction parameters, gas exchange, left and right ventricular function, and hemodynamic parameters. NAVA compared to PSV: (1) improves patient-ventilator interaction reducing AI (coeff - 6.66 95% CI -11.5 to -1.78, p = 0.008); (2) does not improve TAPSE (coeff 0.62 95% CI -1.49 to 2.74, p < 0.557) No differences in terms of pulmonary gas exchange and hemodynamic parameters were detected. NAVA (when compared to PSV) improves patient-ventilator interaction in terms of asynchronies without affecting cardiac biventricular function.Trial registration: NCT04792788, Registration date: 2021-03-11.

Monitor smart, use better: the future of haemodynamic monitoring

The review article "Haemodynamic Monitoring During Noncardiac Surgery" offers valuable insights but lacks evidence linking specific haemodynamic strategies to improved outcomes. There's a need for standardized protocols, ongoing clinician education, and further validation of new technologies. Additionally, balancing the use of invasive versus noninvasive methods and addressing cost-effectiveness and sustainability are essential. Continued research and adaptive practices are crucial for optimizing perioperative care.

Prophylactic endotracheal intubation before endoscopic surgery reduces the rebleeding rate in acute esophagogastric variceal bleeding patients

Objectives

Esophagogastric variceal bleeding (EVB) is one of the main causes of cirrhosis-related deaths, and endoscopic therapy is the first-line treatment of choice. However, the efficacy of prophylactic endotracheal intubation (PEI) before endoscopy remains controversial.

Methods

Data were collected from 119 patients who underwent endoscopic confirmation of an EVB. Inverse probability of treatment weighting was applied to reduce bias between the two groups. The primary outcomes included rebleeding rates within 24 h and 6 weeks post-endoscopic surgery and 6-week mortality.

Results

After endoscopic surgery, the rebleeding rate within 24 h in the PEI group was significantly lower than non-PEI group (1.2 % VS 12.6 %, P-value = 0.025). Although PEI did not reduce 6-week mortality, it significantly reduced the risk of rebleeding within 24 h (odds ratio [OR]: 0.89, 95 % confidence interval [CI]: 0.82-0.97, P = 0.008) and within 6 weeks (hazard ratio [HR]: 0.36, 95%CI: 0.14-0.90, P = 0.029). In multivariate regression analyses, maximum varices diameter >1.5 cm (OR: 1.23, 95 % CI: 1.09-1.37, P < 0.001) was independent risk factor for rebleeding within 24 h. Creatinine (HR: 1.01, 95 % CI: 1.01-1.02, P < 0.001) and international normalized ratio (HR: 2.99, 95 % CI: 1.99-4.65, P < 0.001) were independent risk factors for rebleeding within 6 weeks.

Conclusions

PEI before endoscopic surgery reduced the incidence of rebleeding within 24 h and 6 weeks after endoscopic surgery. However, PEI did not reduce the 6-week mortality rate after endoscopic surgery and might increase the length of hospital stay.

Exploring the need for reconsideration of trial design in perioperative outcomes research: a narrative review

"Enhanced recovery after surgery" is a multimodal effort to control perioperative pathophysiology and improve outcome. However, despite advances in perioperative care, postoperative complications and the need for hospitalisation and prolonged recovery continue to be challenging. This is further complicated by procedure-specific and patient-associated risk factors, given the increase in the number of elderly and frail patients with multiple comorbidities undergoing surgery. This paper is a critical assessment of current methodology for trials in perioperative medicine. We make a plea to reconsider the design of future interventional trials to improve surgical outcome, based upon studies of potentially effective interventions, but often without improvements in recovery. The complexity of perioperative pathophysiology necessitates a procedure- and patient-specific approach whenever outcome is assessed or interventions are planned. With improved understanding of perioperative pathophysiology, the way to improve outcomes looks promising, provided that knowledge and established enhanced recovery programmes are integrated in trial design.

Funding

None.