Journal of Surgery and Anesthesia

Surgical Anesthesia: Maintenance and Monitoring

Michael Thompson^* Department of Anesthesiology, Harvard Medical Science, Bostonm.thompson@hms.harvard.edu, USA
^*Correspondence: Michael Thompson, Department of Anesthesiology, Harvard Medical Science, Bostonm.thompson@hms.harvard.edu, USA, Email:

Received: 29-Aug-2025, Manuscript No. JSA-25-30604; Editor assigned: 01-Sep-2025, Pre QC No. JSA-25-30604 (PQ); Reviewed: 15-Sep-2025, QC No. JSA-25-30604; Revised: 22-Sep-2025, Manuscript No. JSA-25-30604 (R); Published: 29-Sep-2025, DOI: 10.35248/2684-1606.25.9.297

Description

The surgical stage of anesthesia, also known as the stage of maintenance, is the phase in which a patient achieves adequate depth for pain-free surgery while maintaining hemodynamic and respiratory stability. This stage follows the induction and excitement phases and is the primary target of general anesthesia. Maintaining a balanced anesthetic state involves careful titration of anesthetic agents, including intravenous drugs, inhalational agents, opioids and muscle relaxants. Anesthetic depth is continuously monitored using clinical signs, such as heart rate, blood pressure, respiratory pattern, eye movement and reflex responses, as well as advanced monitoring tools, including Bispectral Index (BIS) or entropy devices. Adequate anesthesia ensures patient immobility, suppresses stress responses to surgical stimuli and provides analgesia, all while avoiding over-sedation or prolonged recovery.

During the maintenance phase, anesthesiologists must address several physiological considerations. Cardiovascular function may be affected by anesthetic depth and surgical stimuli, requiring close observation and pharmacological support if necessary. Respiratory function must be maintained either through controlled ventilation or assisted spontaneous breathing. Temperature, fluid balance and blood loss are also critical factors influencing anesthetic management. Modern anesthetic machines and monitoring technologies enable precise control of inhalational agent concentrations and continuous infusion of intravenous agents. Adjustments are made based on surgical events, patient physiology and real-time monitoring data.

Pain management is a central component of the surgical stage. Opioids, non-opioid analgesics and regional anesthetic techniques may be used in combination to achieve multimodal analgesia, reducing overall drug requirements and minimizing side effects. Neuromuscular blockers facilitate surgical access by relaxing skeletal muscles and optimizing operative conditions, with reversal agents administered as needed to restore muscle function before emergence. The balance between adequate anesthesia and physiological stability is delicate, as both underand over-anesthetizing the patient can result in complications. Skilled anesthesiologists integrate pharmacology, monitoring and clinical judgment to achieve this equilibrium.

The surgical stage of anesthesia, or maintenance phase, is the period during which the patient remains at an adequate depth of anesthesia for pain-free and immobile surgical conditions. Following induction and the excitement phase, this stage is critical for ensuring that the patient tolerates surgical stimuli while maintaining cardiovascular and respiratory stability. The maintenance phase involves continuous administration of anesthetic agents, which may include intravenous drugs, inhalational agents, opioids and neuromuscular blockers. Clinicians carefully titrate these agents based on physiological responses, surgical events and real-time monitoring.

Hemodynamic stability is a key consideration during the maintenance phase. Anesthetic agents influence vascular tone, cardiac output and autonomic responses. Inhalational agents such as sevoflurane and desflurane provide predictable cardiovascular effects, while intravenous agents like propofol and remifentanil allow precise titration and rapid adjustments. Monitoring tools, including continuous blood pressure, electrocardiography, pulse oximetry, capnography and advanced indices such as the Bispectral Index (BIS), help anesthesiologists assess anesthetic depth, detect early physiological changes and guide drug administration. These technologies reduce the risk of under- or over-anesthetizing the patient, which can lead to intraoperative awareness, excessive sedation, or hemodynamic instability.

Pain management during the surgical stage is multifaceted. Opioids, non-opioid analgesics and regional anesthesia techniques are often combined to achieve multimodal analgesia. Neuromuscular blockers facilitate surgical access by providing skeletal muscle relaxation, with reversal agents administered toward the end of the procedure to restore muscle function. Fluid management, temperature regulation and careful monitoring of blood loss are also essential to maintaining physiological homeostasis during surgery.

Emerging technologies, such as automated infusion systems, computer-assisted anesthesia delivery and predictive analytics, are transforming the maintenance phase. Machine learning algorithms can predict patient-specific responses to anesthetic agents and guide dosing to optimize safety and efficiency. Ultrasound-guided regional anesthesia complements systemic drugs, reducing opioid requirements and improving postoperative recovery.

Conclusion

The surgical stage of anesthesia is the cornerstone of safe and effective perioperative care, requiring precise agent titration and vigilant monitoring. Maintaining adequate depth ensures analgesia, immobility and suppression of stress responses. Integrating pharmacological strategies with advanced monitoring and multimodal analgesia improves patient safety and surgical outcomes. Skilled anesthetic management during this stage is critical for optimizing recovery and minimizing intraoperative complications.