Contents

1. STRUCTURE AND FUNCTION OF SKIN ...... 1 Structure of skin ...... 1 Formation of skin ...... 4 Skin as a barrier to moisture...... 5 Potentiation of skin damage by body fluids ...... 9 2. CLASSIFICATION OF WOUNDS ...... 13 Definition of a wound ...... 13 Wound classification systems ...... 14 3. WOUNDS: COUNTING THE COST...... 19 Introduction...... 19 Cost of treating ‘chronic’ wounds...... 19 Containing treatment costs...... 21 4. MECHANISMS OF WOUND HEALING ...... 25 Introduction...... 25 Wound management techniques...... 25 Monitoring progress towards healing...... 30 Problems associated with wound healing...... 32 5. WOUND EXUDATE...... 39 Introduction...... 39 Properties of exudate...... 39 Exudate as a diagnostic aid ...... 44 Exudate handling mechanisms...... 45 Management of exudate in clinical practice...... 54 6. THE DEVELOPMENT OF DRESSINGS ...... 57 Introduction...... 57 Early wound dressings ...... 58 Dressings and moist wound healing...... 64 The ‘ideal’ dressing...... 70 7. LABORATORY TESTING OF SURGICAL DRESSINGS...... 79 Introduction...... 79 Importance of laboratory testing ...... 80 Standards for dressings ...... 80 Fluid handling tests ...... 81 Fluid affinity testing...... 94 Low-adherence...... 95 Conformability...... 97 Microbiological tests...... 98

Odour control ...... 104 Biological tests ...... 106 8. LOW-ADHERENT DRESSINGS ...... 111 Impregnated fabric dressings...... 111 Alternative forms of low-adherent dressings...... 119 9. FILM DRESSINGS ...... 139 Introduction ...... 139 Examples of modern film dressings ...... 144 Properties of film dressings ...... 144 Experimental studies ...... 151 Clinical experience with film dressings...... 154 10. FOAM DRESSINGS...... 181 Introduction ...... 181 History of foam dressings...... 181 Classification of foam dressings...... 183 Key properties of foam dressings ...... 198 Clinical experience with foam dressings ...... 206 11. POLYSACCHARIDE FIBRE DRESSINGS...... 237 Introduction ...... 237 Alginate dressings ...... 237 Clinical experience with alginate dressings...... 247 Carboxymethylcellulose dressings ...... 271 Hyaluronan ...... 280 Chitin and chitosan...... 285 Bacterial cellulose ...... 287 Oxidised cellulose ...... 289 Current status of polysaccharide fibre dressings ...... 289 12. HYDROCOLLOID DRESSINGS ...... 301 Introduction ...... 301 Development of hydrocolloid dressings ...... 302 Physical properties...... 309 Experimental studies ...... 313 Microbiological considerations ...... 323 Clinical experience with hydrocolloid dressings...... 329 13. POLYSACCHARIDE BEADS ...... 375 Introduction ...... 375 Structure and mode of action...... 375 Effect upon wound healing...... 379 Clinical experience ...... 381 14. HYDROGELS AND XEROGELS ...... 393 Introduction ...... 393 Properties of hydrogels...... 393

Hydrogel sheet dressings...... 398 Amorphous hydrogel dressings...... 412 Xerogels ...... 422 15. HONEY AND SUGAR DRESSINGS ...... 429 Introduction...... 429 Sugar as a wound dressing ...... 429 Honey as a wound dresssing ...... 434 16. SILVER DRESSINGS...... 473 Introduction...... 473 Properties of silver dressings...... 484 Toxicity of silver dressings ...... 503 Clinical experience with silver dressings ...... 509 Resistance to silver dressings...... 522 Conclusions...... 523 17. ODOUR CONTROLLING DRESSINGS...... 533 Introduction...... 533 Activated charcoal dressings...... 536 Clinical experience with charcoal dressings ...... 542 18. SILICONE DRESSINGS FOR SCAR TREATMENT ...... 547 Introduction...... 547 Commercial silicone dressings...... 549 Clinical experience with silicone dressings...... 549 19. MAGGOT THERAPY...... 563 Background to maggot therapy ...... 563 History of maggot therapy...... 567 Basic biology of Lucilia sericata ...... 573 Production and use of medical maggots...... 578 Method of application ...... 580 Mechanism of action...... 586 Early accounts of the use of maggot therapy...... 595 Modern maggot therapy ...... 596 Contraindications and side effects...... 607 Examples illustrating the use of maggots in clinical practice...... 611 Practical problems associated with maggot therapy...... 614 Maggots in veterinary practice...... 616 Myths and legends related to maggot therapy...... 617 20. NEGATIVE PRESSURE WOUND THERAPY...... 633 Historical background ...... 633 Development of NPWT...... 634 Method of use...... 636 Clinical experience with NPWT ...... 638 Cost implications of treatment ...... 640 Comparisons between NWPT systems...... 641

mode of action ...... 643 The future of NPWT...... 646 21. DRESSING SELECTION...... 651 Factors that impact upon dressing selection ...... 651 Black necrotic wounds ...... 652 Yellow sloughy wounds ...... 657 Red granulating wounds ...... 659 Pink epithelializing wounds...... 667 Malignant wounds ...... 669 Infected wounds...... 670 22. BUYER’S GUIDE...... 675 List of products in alphabetical order ...... 675 Manufacturers’ contact details...... 681 23. INDEX...... 687