Recent Advancements in Anaesthesiology
The field of anaesthesiology has evolved significantly with the introduction of novel sedative agents, enhanced airway management technologies, and refined perioperative protocols that prioritize patient safety and optimize recovery outcomes.
Novel Sedative and Anesthetic Agents
Remimazolam: A New Ultra-Short-Acting Benzodiazepine
Remimazolam represents the most significant recent advancement in intravenous sedation, offering rapid onset and offset with minimal cardiovascular and respiratory depression. 1, 2
Remimazolam is FDA-approved for procedural sedation in adults undergoing procedures lasting 30 minutes or less, with dosing of 5 mg IV push over 1 minute initially, followed by 2.5 mg supplemental doses as needed (at least 2 minutes apart). 1
The drug is rapidly metabolized by tissue esterases to an inactive metabolite, resulting in predictable recovery times regardless of infusion duration—a major advantage over midazolam and propofol. 2, 3
Remimazolam causes significantly less cardiovascular depression, respiratory depression, and injection pain compared to propofol, while maintaining the reversibility advantage of benzodiazepines with flumazenil. 2, 3
The agent has been approved for anesthesia in Japan and South Korea, procedural sedation in the United States, China, and Europe, representing a paradigm shift in short-procedure sedation. 2
Refined Ketamine Applications
Ketamine has experienced a renaissance with evidence-based perioperative protocols that maximize analgesic benefits while minimizing adverse effects. 4, 5
For perioperative pain management, ketamine should be limited to two specific scenarios: surgery with high risk of acute or chronic postoperative pain, and patients with vulnerability to pain (particularly those on long-term opioids). 4
The maximum recommended dose is 0.5 mg/kg/h after anesthesia induction, with continuous infusion at 0.125-0.25 mg/kg/h, and the infusion must be stopped 30 minutes before the end of surgery to avoid postoperative hallucinations without enhanced analgesia. 4
When ketamine is administered for moderate procedural sedation, care consistent with that required for general anesthesia must be provided, with practitioners capable of rescuing patients from unintended deep sedation. 4, 5
Strong evidence supports intravenous ketamine use in the perioperative period to reduce opioid consumption in the first 24 hours after hip and knee arthroplasty. 4
Co-induction Techniques for Balanced Anesthesia
A co-induction technique using small doses of ketamine, midazolam, or fentanyl followed by reduced doses of propofol or sevoflurane provides optimal balance, minimizing negative effects while maximizing therapeutic benefits. 6
Propofol combined with small doses of an opioid analgesic and a benzodiazepine allows analgesia and amnesia to be achieved with subhypnotic doses of propofol (average cumulative doses reduced to 65-100 mg during colonoscopy and 35-70 mg during EGD). 6
This approach enables more precise dose titration with smaller bolus doses (5-15 mg of propofol) while retaining pharmacologic reversibility using naloxone or flumazenil. 6
Airway Management Evolution
Videolaryngoscopy and Supraglottic Airways
Videolaryngoscopes and supraglottic airway devices have transitioned from novel technologies to routine practice, fundamentally changing airway management strategies. 7
By the time of the 4th National Audit Project (NAP4), supraglottic airway devices were being used in 56.2% of general anaesthetics, with case series now describing SAD use in patients for up to 11 hours. 7
The 4th National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society published in 2011 has influenced airway management worldwide, establishing evidence-based recommendations that complement clinical guidelines. 7
High-Flow Nasal Oxygen
The role of high-flow nasal oxygen in anaesthesia is now being realized and developed as an important tool for preventing hypoxaemia during airway management. 7
- High-flow nasal oxygen provides continuous oxygenation during intubation attempts and procedural sedation, extending safe apnea time and reducing hypoxemic events. 7
Modified Cricoid Pressure Recommendations
Current recommendations are that cricoid pressure be applied, but it should be released rapidly should airway difficulty be encountered. 7
- This represents an evolution from rigid application protocols to a more flexible, patient-safety-centered approach that prioritizes successful airway management over aspiration prevention when the two conflict. 7
Enhanced Recovery and Perioperative Optimization
Enhanced Recovery After Surgery (ERAS) Programs
Enhanced recovery programs use extensive phase-specific perioperative interventions that have been shown to prevent early postoperative complications, minimize opioid exposure, and reduce time to extubation, ICU stay, and hospital length of stay after cardiac surgery. 7
Components include liberation of "nothing by mouth" status, bundled surgical site infection prevention, multimodal nonopioid analgesics, protocolized short-acting anesthetics, targeted-organ perfusion strategies, and early postoperative ambulation. 7
Nonopioid medications (acetaminophen, ketamine, dexmedetomidine) and regional techniques (truncal nerve blocks) as part of a multimodal analgesic approach have been shown to reduce perioperative opioid use in cardiac surgery. 7
Lung-Protective Ventilation Strategies
An intraoperative lung-protective ventilation strategy (tidal volume of 6-8 mL/kg predicted body weight + positive end-expiratory pressure) has been shown to improve pulmonary mechanics and reduce postoperative pulmonary complications. 7
Advanced Monitoring Technologies
Intraoperative monitoring of cerebral oxygen saturation (near-infrared spectroscopy) to detect cerebral hypoperfusion has been shown to guide anesthetic decision-making and may prevent postoperative neurocognitive dysfunction. 7
- Intraoperative transesophageal echocardiography aids in real-time assessment of hemodynamic status, regional wall motion, ventricular function, valve anatomy, and diastolic function, particularly valuable in cardiac and high-risk non-cardiac surgery. 7
Neuromuscular Blockade Management
Quantitative Monitoring and Reversal
Pharmacological reversal of neuromuscular blockade is strongly recommended following the use of muscle relaxants during general anesthesia to prevent residual neuromuscular blockade and associated complications. 8
Quantitative adductor pollicis monitoring is recommended for diagnosing residual neuromuscular blockade, as no clinical test is sensitive enough to detect residual blockade reliably. 8
A train-of-four ratio (T4/T1) of at least 0.9 at the adductor pollicis is required to eliminate the possibility of residual neuromuscular blockade. 8
After administering a non-depolarizing muscle relaxant, await spontaneous reversal with four detectable muscle responses at the adductor pollicis following TOF stimulation before administering neostigmine, as earlier administration results in longer time to achieve full reversal. 8
Residual neuromuscular blockade is associated with higher morbidity and mortality within the first 24 hours postoperatively, increased risk of critical respiratory events, postoperative pneumonia, pharyngeal muscle dysfunction, and delayed discharge from recovery. 8
Sedation Practice Refinements
Procedural Sedation Guidelines
For procedural sedation, continuous monitoring of vital signs including capnography is now standard, with contemporaneous recording of monitored parameters required. 7
An individual dedicated to patient monitoring, not involved in the conduct of the diagnostic or therapeutic procedure, must be present during moderate procedural sedation. 7
Resuscitative drugs and age- and size-appropriate equipment for bag/valve/mask assisted ventilation must be immediately available during administration of sedative agents. 7
Fasting Recommendations
The American Society of Anesthesiologists recommends minimal fasting times of 2 hours for clear liquids, 4 hours for breast milk, and 6 hours for infant formula, nonhuman milk, or light meals. 7
Intensive Care Sedation Evolution
Return to Light Sedation Protocols
Institutions that used light sedation and spontaneous awakening and breathing trials, even among patients with COVID-19 who were mechanically ventilated, reported patients had more days alive and free of mechanical ventilation. 7
Multicomponent bundles that incorporate optimization of patient pain with an analgesic-based sedation practice and daily spontaneous awakening and breathing trials remain a priority, as deviation from these practices during the COVID-19 pandemic resulted in worse patient outcomes. 7
Outcomes of critically ill patients without COVID-19 worsened during the pandemic in 2020 as a result of deviation from best practices, including analgosedation, spontaneous awakening and breathing trials, and avoidance of benzodiazepines. 7
Emerging ICU Sedation Technologies
Volatile anesthetics for sedation with dedicated delivery devices have recently been approved for use in Europe, with use increasing primarily because of "need for additional sedative" and "shortage of intravenous sedatives" during the pandemic. 7
Volatile anesthetics produce rapidly reversible, deep sedation among critically ill patients, even when sedated for long periods, representing a potential alternative to traditional intravenous sedation. 7
Xenon gas for sedation is gaining new attention given its safety profile, including relative hemodynamic stability with administration. 7
Anesthesia for Non-Cardiac Surgery
Neuraxial Anesthesia Benefits
When epidurals or spinals were used to replace general anesthesia, there was a significant 29% decrease in the risk of dying during surgery, with a 55% decrease in the risk of pneumonia. 7
- Neuraxial anesthesia was associated with a significantly lower risk of pneumonia in patients undergoing lower-limb revascularization, though it failed to decrease the risk of myocardial infarction. 7
Blood Pressure Management
Percentage decreases >20% in mean arterial pressure, or mean arterial pressure values <60 mmHg for cumulative durations of >30 minutes, are associated with a statistically significant increase in the risk of postoperative complications and death, including myocardial infarction and stroke. 7
Pre-Hospital Anesthesia Advances
Sedation Before Rapid Sequence Induction
Judicious use of sedation can facilitate the establishment of monitoring and ensure adequate pre-oxygenation in confused, agitated, or combative patients requiring pre-hospital emergency anesthesia. 7
For sedation, the intravenous route should be used in preference to intramuscular or other routes, with titration of small doses (1-2 mg increments of midazolam) to achieve the desired effect. 7
Where intravascular access is difficult, intramuscular ketamine should be used as it will not cause respiratory or cardiovascular collapse, allowing establishment of access before proceeding with anesthesia. 7
Common Pitfalls and Caveats
Failure to monitor neuromuscular function quantitatively can lead to undetected residual blockade, as clinical tests alone are inadequate for assessing recovery. 8
Administering neostigmine too early (before four TOF responses are visible) results in ineffective reversal and prolonged recovery times. 8
Avoid rapid administration of co-induction agents, as this increases the risk of hemodynamic instability and respiratory depression, despite reduced individual drug doses. 6
Continuation of ketamine treatment in the postoperative period increases risk of hallucinations without significantly enhancing analgesic effect, so infusions must be stopped 30 minutes before surgery ends. 4
When using remimazolam, personnel must be trained in detection and management of airway obstruction, hypoventilation, and apnea, as the drug has been associated with hypoxia, bradycardia, and hypotension. 1
Concomitant use of benzodiazepines with opioid analgesics may result in profound sedation, respiratory depression, coma, and death, requiring continuous monitoring for respiratory depression and depth of sedation. 1