Section editor: Paul Banaszkiewicz

Segment author: Lorcan McGonagle

Document history: 1/8/2019

• The pneumatic tourniquet was introduced in 1904 by Harvey Cushing to maintain a bloodless field during extremity surgery.
• Tourniquets should be deflated at the time of application, proximal to the intended surgical field. The tourniquet cuff bladder requires a source of compressed gas to supply a carefully controlled amount of tourniquet pressure. The gas used may be nitrogen, ambient air, or some other gas.
• Indications:

1. Emergency: control of life/limb threatening bleeding.
2. Elective: minimise intra-operative bleeding and improve visibility within the surgical field.

• Contraindications:

1. Underlying vascular graft
2. Peripheral vascular disease
3. Poor skin
4. Deep vein thrombosis
5. Arterovenous fistula
6. Sickle cell disease

• Exsanguination of the limb prior to tourniquet inflation decreases the amount of blood distal to the cuff. This reduces blood in the surgical field. This can be performed by elevation, Esmarch bandage distal to proximal for tissue compression. Rhys Davies exsanguinator (partially inflated rubber ‘sausage’).
• Complications (total approximately 1:2400):^1,2

1. Skin burns: this is thought to be due to the result of pooling of skin prep beneath the tourniquet on the padded dressing, having a sustained local irritant effect.
2. Muscle injury
3. Nerve injury
4. Reperfusion injury

• Padding: the tourniquet should be padded with a soft dressing to prevent the wrinkles and blisters that may occur when the skin is pinched. However, using more than two layers of padding results in a significant reduction in the transmitted pressure, which is likely to limit the effectiveness of the tourniquet.³
• Shape: standard straight tourniquets fit well on cylindrically shaped limbs but conical tourniquets fit better on conical shaped (e.g. obese) limbs and are associated with lower arterial occlusion pressures, as are wide tourniquets.⁴
• Duration: tourniquet times greater than 2 hours are associated with a higher risk of muscular injury and neurological complications. This can be offset by temporarily deflating the cuff, to allow reperfusion, prior to re-inflation. Longer deflation times are associated with fewer complications. Neuromuscular injury is greater beneath the cuff than distal to it.^5,6

Figure 1(a) Tournequet

Figure 1(b) Esmarch bandage

Figure 1(c) Rhys Davies Exsanguinator

Figure 1(d) Velband

Figure 1(e) Disposable upper limb tournequet

 

 

Figure 1(f) Tournequet time

Steam sterilisation

• It is non-toxic, inexpensive, rapidly microbicidal, sporicidal, and rapidly heats and penetrates fabrics, although it can lead to instrument corrosion.
• Recognised minimum exposure periods for sterilisation of wrapped healthcare supplies are 30 minutes at 121°C (250°F) in a gravity displacement steriliser or 4 minutes at 132°C (270°C) in a prevacuum steriliser.
• Gravity displacement autoclave: steam is lighter than air, forces air out the bottom of the chamber through the drain vent.
• High speed prevacuum sterilisers: similar to gravity displacement sterilisers except they are fitted with a vacuum pump (or ejector) to ensure air removal from the sterilising chamber and load before the steam is admitted. The advantage of using a vacuum pump is that there is nearly instantaneous steam penetration even into porous loads.
• Mode of action: moist heat destroys microorganisms by the irreversible coagulation and denaturation of enzymes and structural proteins.
• “Flash" steam sterilisation was originally defined by Underwood and Perkins as sterilisation of an unwrapped object at 132°C for 3 minutes at 27–28 lb of pressure in a gravity displacement steriliser.
• It is not recommended as a routine sterilisation method because of the absence of protective packaging following sterilisation, and possibility of contamination of processed items during transportation to the operating rooms.
• It is considered acceptable for processing cleaned patient care items that cannot be packaged, sterilised, and stored before use. It is also used when there is insufficient time to sterilise an item by the preferred package method.

Figure 2. High speed prevacuum sterilisers

Ethylene oxide “gas” sterilisation

• Mode of action: microbicidal activity results from the alkylation of protein, DNA, and RNA. Alkylation, or the replacement of a hydrogen atom with an alkyl group, within cells prevents normal cellular metabolism and replication.
• The main disadvantages associated with ETO are the lengthy cycle time, the cost, and its potential hazards to patients and staff; the main advantage is that it can sterilise heat or moisture-sensitive medical equipment without deleterious effects on the material used in medical devices.

Hydrogen peroxide gas plasma

• Gas plasmas are generated in an enclosed chamber under deep vacuum using radio frequency or microwave energy to excite the gas molecules and produce charged particles, many of which are in the form of free radicals.
• Free radicals within a plasma field are capable of interacting with essential cell components (e.g. enzymes, nucleic acids) and thereby disrupt the metabolism of microorganisms.
• Uses: materials and devices that cannot tolerate high temperatures and humidity, such as some plastics, electrical devices, and corrosion-susceptible metal alloys.⁷

Hair removal

• Razors can rapidly remove hair from the surgical field, but may result in small cuts and abrasions. This minor skin damage can provide an area where bacterial flora can multiply and potentially infect the surgical incision site.
• Clippers mechanically trim the hairs close to the skin, effectively removing it from the field, and avoid the skin trauma caused by the sharp blade of a razor.
• Depilatory creams remove hair via chemical means, although these are costly and may cause a sensitivity reaction at the site.
• Removing hair immediately before surgery may decrease infection rates.
• A recent Cochrane Review found no statistically significant effect on surgical site infection (SSI) rates of hair removal. However the low numbers involved do not allow confidence in a conclusion.
• When it is necessary to remove hair, clippers are associated with fewer SSIs than razors. There was no significant difference in SSI rates between depilatory creams and shaving, or between shaving or clipping the day before surgery or on the day of surgery.⁸

Figure 3(a) Disposable razor

Antibiotics

• Prophylactic antibiotics purpose: preventing infection when infection is not present but the risk of postoperative infection is present. The goal of antimicrobial prophylaxis is to achieve serum and tissue drug levels that exceed, for the duration of the operation, the minimum inhibitory concentration for the organisms likely to be encountered during the operation.
• Current AAOS guidelines for antibiotics in total joint replacement recommend:
• The antibiotic used for prophylaxis should be carefully selected, consistent with current recommendations in the literature, taking into account the issues of resistance and patient allergies.
  • Usually cefazolin or cefuroxime. Clindamycin or vancomycin may be used for patients with a confirmed beta-lactam allergy. Vancomycin may be used in patients with known MRSA colonisation.
  • Timing and dosage of antibiotic administration should optimise the efficacy of the therapy.
    • Prophylactic antibiotics should be administered within one hour prior to skin incision.
    • Duration of prophylactic antibiotic administration should not exceed the 24-hour postoperative period.
      • http://www.aaos.org/about/papers/advistmt/1027.asp

Figure 4. Prophylatic antibiotics

Glycaemic control

• Poor peri-operative glycaemic control is associated with higher rates of SSIs, as well as other complications.
• This is thought to be a result of impaired granulocyte function associated with poorly controlled diabetes.^9–13

Body exhaust suits

• These have been shown to decrease infection rates and bacterial air contamination when compared with conventional theatre gowns.^14,15
• Although there is some evidence to suggest that they may not be that effective. This may be due to the suits disrupting the laminar flow, or from inadvertent contamination from light handles or other theatre equipment.¹⁶

Figure 5. Surgical hoods

• Although controlled hypothermia is used in some instances in neuro, cardiac and vascular surgery it is to be avoided in orthopaedic surgery to minimise the risk of delayed anaesthetic recovery, bleeding diathesis and surgical site infections.¹⁷
• Forced air warming uses a disposable blanket placed in top of the patient and connected via a hose to a warming unit that filters, warms and pumps the air. It is turned on after the surgical site has been prepared and draped. N.B. Any leakage of warm air may upset laminar flow.
• Fluid warming: intravenous fluids (≥500 ml) and blood products should be warmed to 37° using a fluid warming device.
• Patient warming mattress: NICE approves the inditherm mattress, a flexible, carbon-based conductive polymer that generates a uniform direct heating surface. A pressure redistribution foam pad is designed to mould itself to the shape of the patient.¹⁸

Figure 6(a) Bair Hugger

• The United States Food and Drug Administration defines a skin disinfectant as a “fast acting, broad-spectrum and persistent antiseptic-containing preparation that significantly reduces the number of microorganisms on intact skin.”
• Before a patient’s skin is prepared for a surgical procedure, it should be cleansed of gross contamination (e.g. dirt, soil or any other debris). The antiseptics used to prepare the skin should be applied with sterile supplies and gloves or by a no-touch technique, moving from the incision area to the periphery. Use pressure, because friction increases the antibacterial effect of an antiseptic.

Alcohol

•  The exact mechanism by which alcohols destroy microorganisms is not fully understood. The most plausible explanation for their antimicrobial action is that they coagulate (denature) proteins, such as enzymatic proteins, thus impairing specific cellular functions. Alcohols are generally effective against bacteria but do not, however, destroy bacterial spores (e.g. Clostridium difficile). It is also effective against fungi and most viruses with a lipid envelope (influenza, herpes simplex, adenovirus).¹⁹

Figure 7. Alcohol skin prep

Chlorhexidine

• Most commonly formulated as a 4% aqueous solution in a detergent base; however, alcoholic preparations have been shown in numerous studies to have better antimicrobial activity than detergent-based formulations. Bactericidal concentrations destroy the bacterial cell membrane, causing cellular constituents to leak out of the cell and the cell contents to coagulate.
• It has a persistent antimicrobial action that prevents regrowth of microorganisms for up to 6 hours.
• It has little activity against bacterial and fungal spores. Fungicidal action varies with the species. It is active against lipophilic viruses (HIV, influenza, herpes).
• Blood and other organic materials do not affect the antimicrobial activity of chlorhexidine significantly, in contrast to their effects on povidone–iodine.¹⁹
• Povidone–iodine: iodophors are chemical complexes of iodine bound to a carrier such as polyvinylpyrrolidone (povidone) or ethoxylated nonionic detergents (poloxamers), which gradually release small amounts of free microbicidal iodine. The most commonly used iodophor is povidone–iodine. Preparations generally contain 1–10% povidone–iodine.
• The exact mechanism by which iodine destroys microorganisms is not known. It may react with the microorganisms’ amino acids and fatty acids, destroying cell structures and enzymes.
• It is bactericidal, mycobactericidal, fungicidal and virucidal but not sporicidal. Prolonged contact is required to inactivate certain fungi and bacterial spores.¹⁹

Figure 8. Chlorhexidine skin prep

Triclosan and chloroxylenol

• 1% Triclosan has good activity against Gram-positive bacteria, but is less active against Gram-negative organisms, mycobacteria and fungi.
• It is active against enveloped virsuses, but less so against non-enveloped viruses.
• It has a sustained residual effect against resident and transient microbial flora, which is minimally affected by organic matter. However, it is less effective than 2–4% chlorhexidine gluconate when used as surgical scrub solutions.¹⁹

Octenidine

• Octenidine dihydrochloride is a novel bispyridine compound and an effective, safe antiseptic agent. The 0.1% compared favourably with other antiseptics with respect to antimicrobial activity and toxicological properties. It rapidly killed both Gram-positive and Gram-negative bacteria as well as fungi in vitro and in vivo. Octenidine is virucidal against HIV, hepatitis B virus and herpes simplex virus. Like chlorhexidine, it has a marked residual effect.¹⁹

1. Odinsson A, Finsen V, Tourniquet use and its complications in Norway. Journal of Bone & Joint Surgery, British Volume 2006; 88(8): 1090–1092.
2. Dickinson J, Bailey B Chemical burns beneath tourniquets. BMJ 1988; 297(6662): 1513.
3. Rajpura A, Somanchi B, Muir L. The effect of tourniquet padding on the efficiency of tourniquets of the upper limb. Journal of Bone & Joint Surgery, British Volume 2007; 89(4): 532–534.
4. Pedowitz RA, et al. The use of lower tourniquet inflation pressures in extremity surgery facilitated by curved and wide tourniquets and an integrated cuff inflation system. Clinical Orthopaedics and Related Research 1993; 287: 237–244.
5. Pedowitz RA. Tourniquet-induced neuromuscular injury: a recent review of rabbit and clinical experiments. Acta Orthopaedica Scandinavica 1991; 62(suppl 245): 1–33.
6. Horlocker TT, et al. Anesthetic, patient, and surgical risk factors for neurologic complications after prolonged total tourniquet time during total knee arthroplasty. Anesthesia & Analgesia 2006; 102(3): 950–955.
7. Rutala WA, Weber DJ and Healthcare Infection Control Practices Advisory Committee. Guideline for disinfection and sterilization in healthcare facilities. http://www.cdc.gov/hicpac/pdf/guidelines/Disinfection_Nov_2008.pdf 2008.
8. Tanner J, Norrie P, Melen K. Preoperative hair removal to reduce surgical site infection. Cochrane Database Systematic Reviews 2011; 11: CD004122.
9. King JT, et al., Glycemic control and infections in patients with diabetes undergoing noncardiac surgery. Annals of Surgery 2011; 253(1): 158–165.
10. Marchant MH, et al. The impact of glycemic control and diabetes mellitus on perioperative outcomes after total joint arthroplasty. The Journal of Bone & Joint Surgery 2009; 91(7): 1621–1629.
11. Hill HR, et al. Impaired leukotactic responsiveness in patients with juvenile diabetes mellitus. Clinical Immunology and Immunopathology 1974; 2(3): 395–403.
12. Nolan CM, Beaty HN, Bagdade JD. Further characterization of the impaired bactericidal function of granulocytes in patients with poorly controlled diabetes. Diabetes 1978; 27(9): 889–894.
13. Tan JS, et al. Neutrophil dysfunction in diabetes mellitus. Journal of Laboratory and Clinical Medicine 1975; 85(1): 26–33.
14. Lidwell O, et al. Effect of ultraclean air in operating rooms on deep sepsis in the joint after total hip or knee replacement: a randomised study. BMJ 1982; 285(6334): 10–14.
15. Sanzén L, Walder M. Air contamination during total hip arthroplasty in an ultraclean air enclosure using different types of staff clothing. Journal of Arthroplasty 1990; 5(2): 127–130.
16. Hooper G, et al. Does the use of laminar flow and space suits reduce early deep infection after total hip and knee replacement? Bone & Joint Journal 2011; 93(1): 85–90.

17.  Reynolds L1, Beckmann J, Kurz A. Perioperative complications of hypothermia. Best Pract Res Clin Anaesthesiol 2008; 22(4): 645–657.

18.  http://www.nice.org.uk/guidance/mtg7/resources/guidance-inditherm-patient-warming-mattress-for-the-prevention-of-inadvertent-hypothermia-pdf.

19.  WHO Guidelines for Safe Surgery. World Health Organization, Geneva, 2009.