Chapter 6: Plastic Surgery. - Famona Site

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Surgical DebridementTimely surgery is the primary and essential component of a combined managementregime. The aim is complete surgical excision of infected and necrotic tissue. This mayinvolve repeated exploration and incisions and the performance of fasciotomies to ensuredecompression and drainage of muscle compartments. Even amputations may be necessary.The appearance of involved muscle is characteristic. It must, however, be viewed by directsurgical exposure, since many of the changes are not apparent when superficially inspectedthrough the edges of a wound. On surgical exploration the muscle is initially pale andoedematous (looking like a piece of steak seared over a fire) and does not contract whenincised; on further dissection a red, non-viable muscle is found.<strong>Surgery</strong> also allows the essential establishment of haemostasis and the evacuation ofhaematomas. This prevents the release of catalase by disintegrating erythrocytes, which in turnwould have been used by the anaerobes in the wound to metabolize would-be-self destructingperoxides formed within the bacteria. In this way the bacteria may prevent self-destruction.Antibiotic prophylaxis and therapyIndividual circumstances should be taken into account when prophylactic antibioticadministration is considered. Aerobic and anaerobic bacteria are invariably components of anysuppurative infection that involves Clostridia and should be treated with penicillin and broadspectrumantibiotics designed to suppress both. Similarly, prophylactic antibiotics areindicated in cases of contamination from bowel perforation where surgery was delayed. Foraerobes and anaerobes in this setting, an aminoglycoside (i.e. gentamycin, tobramycin oramikacin) and metronidazole respectively are indicated.When gas gangrene is evident, judicious surgical debridement is required and antibiotictherapy is indicated only when the process extends into adjacent tissues or when systemicsigns of fever and sepsis are present. Penicillin G acts against nearly all strains of Clostridiumperfingens and it is the drug of choice for prophylaxis and treatment of gas gangrene.The sodium salt of penicillin is preferred to the potassium salt, because the latter willexacerbate the hyperkalaemia that may already be present due to haemolysis, tissue necrosisand renal failure. The recommended dosages are 10 to 24 million units per day. In thepresence of proven penicillin allergy, tetracycline is recommended instead (dosage 2-4 g IVper day). Chloromycetin (in high doses), erythromycin and clindamycin have also beenrecommended, although clindamycin has been reported to be somewhat less effective.Hyperbaric Oxygen (HBO)This is the third component of the therapy of gas gangrene. Both bactericidal effects(in vitro) and bacteriostatic effects of Clostridia have been reported with use of HBO. HBOtherapy interferes with the process of exotoxin liberation, in that the tissue oxygen tension iselevated. Tissue oxygen tension of 20 kPa (150 mm Hg0 inhibits production of the exotoxinC-lecithinase, but does not neutralize existing toxins. HBO therapy supresses the growth ofClostridia, in that a less favourable environment is created for the growth of anaerobes. With38
HBO therapy patients are exposed to 100% oxygen at a pressure of 3 atmospheres for oneto two hours. The procedure is repeated 5-12 hourly for six treatments.The frequency of complications related to HBO is low. Oxygen toxicity, barotrauma,decompression sickness and damage to the lungs have been mentioned in the literature. Onestudy reported over 20000 hyperbaric compressions without a chamber-related death. Animportant role of HBO is to counteract the hypoxic environment in which Clostridia thrive,in that peroxides are formed within the organism, killing it. The presence of catalase inerythrocytes and muscle cells inactivates the peroxides. <strong>Surgery</strong> thus complements the effectsof HBO by removing the necrotic tissue and red blood cells which may release catalase.Clostridium perfringens stops producing toxins in ambient oxygen tension of 10.7 kPa (80mm Hg) or greater. With HBO, tissue oxygen tension of 33.3 kPa (250 mm Hg) at 2 ATAoxygen and 60 kPa (450 mm Hg) at 3 ATA are achieved. Tissue oxygen tension whilebreathing air is in the range of 4-5.3 kPa (30 to 40 mm Hg). HBO treatment at 2.5 bar (36.7psi), in order to achieve an oxygen tension of 33.3 kPa (250 mm Hg) in the infected area andyet not exceed the cerebral oxygen toxicity threshold, is suggested. The management ofclostridial myonecrosis can be summarized as follows:1. Diagnosis- high index of suspicion- history- disproportionate wound pain- toxicity- examination of the wound:- erythema- brick-coloured watery discharge with a bad mousey odour- haemorrhagic bullae - possibly crepitations- laboratory- gram-positive organisms on staining- fascicular gas pattern on X-ray2. Initial Management- resuscitation- IV and arterial lines- Swan-Ganz catheter placement- antibiotic cover- sodium penicillin drug of choice or- tetracycline or- chloramphenicol or- clindamycin3. Transfer to Major Hospital4. Combined Management- fluid and blood administration- surgical debridement- antibiotic therapy continued- hyperbaric oxygen therapy.5. Reconstruction/Rehabilitation39
Page 1 and 2: C J Mieny, U Mennen: Principles of
Page 3 and 4: SkinThe anatomy of the blood supply
Page 5 and 6: BoneAttempts are made to remove as
Page 7 and 8: Brain: DebridementThe regeneration
Page 9 and 10: Chapter 6.2: Closure of Wounds and
Page 11: Skin OverlapWhy, when simple suture
Page 14 and 15: diameter of a vessel becomes a sign
Page 16 and 17: CommentClosure of Wounds and Materi
Page 18 and 19: Facial Human BitesIn the head regio
Page 20 and 21: After irrigation, removal of devita
Page 22 and 23: Sites Bitten by DogsThese include:-
Page 24 and 25: Injury Type- large wounds (lacerati
Page 26 and 27: Snake BitesBy definition snake bite
Page 28 and 29: Following poisonous snake bites:- t
Page 30 and 31: with the shark. In addition the vic
Page 32 and 33: - I think the fact that with minor
Page 34 and 35: Gas gangrene has often erroneously
Page 36 and 37: Diagnosis and Special Investigation
Page 40 and 41: PrognosisIn spite of remarkable adv
Page 42 and 43: symptoms of the disease. The incuba
Page 44 and 45: Prophylaxis After Trauma- Prompt an
Page 46: - Assisted ventilation and administ
Page 49 and 50: are deep with superficial areas aro
Page 51 and 52: Diagnosis and Special Investigation
Page 53 and 54: Blood/Plasma/ColloidsThese are usua
Page 55 and 56: Early excision and skingrafting of
Page 57 and 58: DiagnosisWound swabs are often not
Page 59 and 60: Early excision of deep localized in
Page 61 and 62: The use of 1% copper sulphate solut
Page 63 and 64: - Massively increased metabolic rat
Page 65 and 66: - the fascial plexuses both deep to
Page 67 and 68: Full Thickness Skin GraftsThese gra
Page 69 and 70: Random FlapsThese are skin flaps mo
Page 71 and 72: very largely on the experience of t

Chapter 6: Plastic Surgery. - Famona Site

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