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Anaesthesiology
Inflammation, Wound Healing, and Infection
Built from Barash Clinical Anesthesia, 9th Edition
What’s inside
7 sections · 199 slides
Overview
- Scope of this topic
- How the topic is organised
- Burden of surgical site infection
- Determinants of wound outcome
- Categories of surgical site infection
- Criteria for defining a surgical site infection
- Criteria for defining a surgical site infection (continued)
- Criteria for defining a surgical site infection (continued)
- Criteria for defining a surgical site infection (continued)
- Criteria for defining a surgical site infection (continued)
- Criteria for defining a surgical site infection (continued)
Infection control
- Primacy of hand hygiene
- Semmelweis and puerperal fever
- Reasons Semmelweis was ignored
- Resident and transient skin flora
- Sources of hand contamination
- Properties of the ideal hand hygiene agent
- Plain soap and water
- Alcohol-based rubs, gels, and foams
- Chlorhexidine
- Toxicity and allergy with chlorhexidine
- Iodine and iodophors
- Choosing an antiseptic
- When hand hygiene is indicated
- Indications for hand hygiene
- Indications for hand hygiene (continued)
- Indications for hand hygiene (continued)
- Hand hygiene technique
- Hand hygiene technique
- Skin care for health care workers
- Skin care
- Barriers to hand hygiene
- WHO Five Moments for hand hygiene
- The Five Moments framework
- Five Moments adapted for the operating room
- Hand hygiene frequency and access in the operating room
- The anaesthesia work area as a reservoir
- Gloves and hand hygiene
- Fingernails and rings
- Surgical masks and surgical site infection
- Continuing role of the mask
- Operating room traffic and airborne contamination
- Central venous catheter infection prevention
- Practical aseptic technique for central lines
- Aseptic technique for neuraxial procedures
- Single-use disposables and infection risk
- Cost and environmental harm of disposables
- Reusable textiles during the SARS-CoV-2 pandemic
Antibiotic prophylaxis
- The decisive period
- Local perfusion and antibiotic failure
- Oxygen as an antibiotic
- Additive effect of oxygen and antibiotics
- Early clinical trials of prophylaxis
- Classen study of antibiotic timing
- Wound infection rate by antibiotic timing
- Aims of an ideal prophylactic agent
- Likely pathogens by wound class
- Staphylococcus aureus and MRSA in surgical site infection
- Cefazolin as the standard agent
- General recommendations for antibiotic prophylaxis
- General recommendations for antibiotic prophylaxis
- Timing of the prophylactic dose
- Drugs that need a slow infusion
- Dosing, redosing, and duration
- Role of the anaesthesiologist in prophylaxis
Mechanisms of wound repair
- Components of the repair response
- Systemic and local factors that impair healing
- Oxygen as the critical element
- Four overlapping phases of wound healing
- Overlap and failure of the phases
- Initial response to injury
- Platelet-derived mediators
- Inflammatory cell arrival
- Clinical signs of the inflammatory phase
- Proteases in early repair
- Origins of the hypoxic acidotic wound
- Leukocyte metabolism and the respiratory burst
- Wound hypoxia as stimulus and as threat
- Oxygen gradients within a wound
- Oxygen, lactate, and peroxide gradients across a wound
- Reading the wound module figure
- Chemotaxis of leukocytes
- Oxygen dependence of neutrophil killing
- Oxidant production in the phagosome
- Chemistry of bacterial killing
- Superoxide and oxidant production within the phagosome
- Following the phagosome schematic
- Oxygen tension and bacterial killing capacity
- Hyperbaric oxygen and the dual role of oxidants
- The proliferative phase
- Angiogenesis and vasculogenesis
- Three waves of angiogenic growth factors
- Lactate and oxygen in granulation
- Mechanism of vasculogenesis
- Collagen production and oxygen
- Hydroxylase dependence on oxygen and vitamin C
- Interdependence of vessels and matrix
- Epithelialization
- Evidence on oxygen and epithelialization
- Maturation and remodeling
- Myofibroblasts and wound contraction
- Time course of tensile strength
- Collagen turnover in the maturing scar
- Hypertrophic scar and keloid
- Determinants of hypertrophic scarring
Wound perfusion and oxygenation
- Goals of the perioperative physician
- Regional differences in healing rate
- Determinants of wound tissue oxygenation
- Arterial oxygen tension versus oxygen content
- Partial pressure as the driving force
- Oxygen consumption in the wound
- Threshold oxygen tensions for repair
- Clinical relevance of wound oxygen tension
- Reservoir function of subcutaneous tissue
- Anaemia and wound healing
- Peripheral vasoconstriction as the dominant impediment
- Stimuli to sympathetic vasoconstriction
- Perioperative sources of vasoconstriction
- Evidence for warming and volume replacement
- Psychological stress and wound hypoxia
- Cochrane review of high inspired oxygen
- Greif trial of 80% versus 30% oxygen
- Belda and Myles trials
- PROXI trial and restricted volume
- Safety of high inspired oxygen
- Balance of evidence on supplemental oxygen
- Perfusion and the effectiveness of antibiotics
- Antibiotic and oxygen diffusion into the fibrin clot
- Oxygen dependence of bactericidal antibiotics
Patient management
- Care bundles in colorectal surgery
- Determinants of surgical site infection risk
- Modifiable preoperative risk factors
- Deciding whether to delay surgery
- Psychosocial stress and wound healing
- Implications of the stress research
- Preoperative checklist for wound outcome
- Preoperative checklist
- Surgical technique and wound outcome
- Reasons a wound cannot be closed
- Mechanisms of anaesthetic hypothermia
- Vasoconstriction at emergence
- Effectiveness of warming methods
- Available active warming technologies
- Intraoperative management checklist
- Intraoperative management
- Goal of intraoperative fluid management
- Estimating preoperative volume status
- Complications of hypovolemia and hypervolemia
- Preoperative carbohydrate clear liquids
- Surgical stress and fluid requirement
- Limitations of routine volume monitors
- Dynamic monitors of fluid responsiveness
- Liberal versus conservative fluid trials
- Limits of the Kabon trial
- Colloid and crystalloid in the restrictive literature
- Interstitial edema and wound healing
- Difficulty interpreting the volume literature
- Current best recommendations for volume
- Standard volume management guidelines for surgical patients
- Standard volume management guidelines for surgical patients (continued)
- Temperature and fluid capacitance
- Intraoperative pain control
- Vulnerability of the wound after surgery
- Perioperative glucose control
- NICE-SUGAR and the current glucose target
- Correcting all vasoconstrictive stimuli
- Requirements for assured local perfusion
- Duration and target of postoperative warming
- Urine output as a guide to perfusion
- Bedside signs of hypovolemia and vasoconstriction
- Postoperative fluid rates after abdominal surgery
- Diuresis and the edematous patient
- Edema versus vasoconstriction
- Vasoconstrictive drugs after surgery
- Postoperative oxygen and pulmonary function
- Postoperative management checklist
- Postoperative management
Summary
- Intraoperative measures that benefit the wound
- Postoperative priorities and the stress response
- Key take-home messages
- References
- References (continued)
- References (continued)
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- References (continued)
- References (continued)
- References (continued)
- Barash, Cullen, and Stoelting's Clinical Anesthesia, 9th Edition