• New tools for airway management
• New minimally invasive hemodynamic monitoring and goal directed fluid therapy
• Oxygenation and ventilation monitoring
• Closed loop drug delivery
• Older and sicker patients undergoing extensive surgical procedures
• Emphasis on shorter hospital stay and fast-track surgery
• Realization that intraoperative management influences postoperative outcome
Wilmore and Kehlet: BMJ 2000; 322: 473-6
• New airway management tools
• CNS monitoring
• Oxygenation (SaO2) and ventilation (CO2) monitoring
• Non-invasive cardiac output monitoring
• Patient and fluid warming systems
• Anesthesia machine – digital ventilation
• MRI compatibility machine and monitoring devices
• Hazards air handling, gas evaluation, gas piping systems
• Automated anesthesia record keeping system
• Communication technology • Home infusion pumps and acute management
systems
Intubation
Mask Ventilation
Supraglottic Devices
Airway Management
Laryngeal Mask Airway (LMA)
• Improves visualization of larynx • Difficulty in tracheal intubation
despite excellent visualization of the larynx
• Need to modify laryngoscopy technique – Laryngoscope blade placed in midline – Drop down the larynx such that the
laryngeal view is not complete – Use bougie or fiberscope
Video Laryngoscopes: Limitations
Right palatopharyngeal fold Can J Anaesth 2007; 54:322-324
• Anterior tonsilar perforation
AnesthAnalg 2007;104 1610-11
• Right palatopharyngeal arch perforation Can J Anaesth 2007;54:54-7
• Soft palate injury
J Clin Anesth 2007;19:619-21
Can J Anaesth 2007;54:588-9
Anesth Analg 2007;104;1609-10
• Pharyngeal injury
Otol Head Neck Surg 2007;37:175-6
• Versatile • Battery operated • Combination with video
laryngoscopes
Limitations • Fragile • Hard to clean
• Preoperative fasting
• Bowel preparation
• Intraoperative losses – Blood loss
– Evaporation
– Third spacing
• General and regional anesthesia – Vasodilatation
Joshi GP: Anesth Analg 2005; 101: 601-5
• We have become desensitized to administration of high fluid volumes (5-6 liters for major surgical procedures) – Kudsk: Ann Surg 2003; 238: 649-50
• Patients typically gain 5 kg of body weight after major surgical procedure – Lobo et al: Best Prac Res Anaesthesiol 2006;
20:439-55
• Perioperative hypervolemia increases postoperative morbidity and mortality
• Holte et al: Br J Anaesth 2002; 89: 622-32
• Perioperative fluid overload is a contributory cause of postoperative complications and death
– National Confidential Enquiry into Perioperative Death (http://www.ncepod.org.uk)
• Individualized fluid therapy that adapts to changing patient needs during the periop period
• Prevents subtle hypovolemia and hypervolemia that might lead to organ dysfunction, increase perioperative complications, and delay recovery
• Goal: maximize tissue O2 delivery with minimal cardiac O2 consumption – Stroke volume most commonly used – Optimal goal remains to be determined
• Fluid challenges to optimize dynamic (flow-related) goals
• Fluid bolus increases stroke volume in hypovolemic state
• In absence of hypovolemia: no change in stroke volume with fluid bolus
<10% Change
LV End Diastolic Volume
Stro
ke V
olum
e
Starling Curve
• Heart rate
• Mean arterial blood pressure
• Central venous pressure
– (CVP or PAWP)
• Stroke volume and cardiac
output derived from arterial
wave analysis (pulse contour,
pulse power analysis, non-
invasive finger pressure, and
plethysmography)
t [s]
P [mm Hg]
• Mechanical ventilation induced variations – Pulse-pressure – Systolic blood pressure – Stroke volume
• Predictors of fluid responsiveness and need for fluid administration
Michard: Anesthesiology 2005; 103: 419-28; Pinsky: Crit Care 2006; 10: 117
Monitoing Brain Perfusion: Cerebral Oximetry
• Measure of tissue perfusion and oxygen delivery
• Can be used as a end-point for goal directed fluid therapy
• With US population aging and becoming obese • 70-80% of patients with OSA are undiagnosed • Increased postoperative respiratory complications
• Respiratory depression rates are between 0.19% and!5.2%
– Reported rates fluctuate due to inconsistencies in!definition
– Commonly defined by decreases in O2 saturation – Definitions do not consider hypoventilation
resulting from shallow breathing or ineffective respirations resulting from sedation
– Rates also may be limited to instances where intervention (i.e., naloxone) is required
Hagle ME, et al. Orthopaedic Nursing. 2004;23:18-27.
Monitoring Ventilation
• End-tidal CO2 waveform – Presence of CO2 confirms
airway patency
• Acoustic probes – Measures air movement and
confirms airway patency
• Bioimpedence technology – Measures respiratory efforts
and provides respiratory rate – No information airway patency
Awake
Light/Moderate Sedation
General Anesthesia
Cortical Silence
100
70
60
40
0
! Target-controlled infusion (TCI) drug delivery – Drugs delivered based on PK models
! Computer-assisted personalized sedation (CAPS) – Sedasys™, McDreamy – TCI + monitoring + smart alarm
system that restricts drug delivery ! Pharmacodynamic drug delivery
– McSleepy – BIS-controlled propofol infusion
Hemmerling T: Curr Opin Anaesthesiol 2009; 22: 757-63
Hemmerling T: Curr Opin Anaesthesiol 2009; 22: 757-63 Hemmerling T: Curr Opin Anaesthesiol 2009; 22: 757-63
Hemmerling T: Curr Opin Anaesthesiol 2009; 22: 757-63 Daniels J, et al: Curr Opin Anaesthesiol 2009; 22: 775-81
Daniels J, et al: Curr Opin Anaesthesiol 2009; 22: 775-81 Allows monitor the patient, surgical field and the patient's vital signs simultaneously without having to turn around to scan the monitors Liu D et al: Curr Opin Anaesthesiol 2009; 22: 796-803
The Microvision Nomad ND2000 (Bothell, WA) head-mounted display Liu D et al: Curr Opin Anaesthesiol 2009; 22: 796-803
• Numerous new technology are being introduced
• Adopting new technology WILL increase healthcare costs!
• Before any new technology is adopted for routine clinical practice, they MUST prove improved perioperative outcome and facilitate recovery Modern Practice
Traditional Practice
Max Plank: JAMA 1999; 282: 1606
