Biophysical Agents Flashcards
What are the primary ways NPWT promotes wound healing?
- removal of wound fluid
- local circulation improved
- mechanical stimulation of cells
- occlusion of the wound from environ contaminants (48-72 hrs)
- Inflammatory mediators and bacteria are removed
When should the wound be reassessed (officially) for signs of healing during negative pressure wound therapy?
2 weeks
What is the average length of treatment for negative pressure wound therapy?
4-6 weeks
How often should a NPWT dressing be changed?
Every 48 hours or 12-24 if infected, but check the seal every 2 hours
Indications for NPWT
- acute and chronic wounds
- acute traumatic & sx wounds healing by primary and secondary intention
- burns
- skin grafts
- chronic wounds associated w/venous insuff, diabetes, pressure, arterial (caution)
- palliative care
Precautions for NPWT
- anticoag & low platelet count
- fistulas
- over bone/tendon/organs
- avoid circumferential occlusive sheeting due to risk of ischemia
- monitor: over bony prominences, bleeding, & notify physician if drainage is sanguineous or if > 2 canisters filled in a 24 hr period
Contraindications NPWT
- wounds > 30% slough or necrotic tissue
- untreated osteomyelitis
- gross infection
- lack of hemostasis
- malignancy in treatment area
- blood dyscrasia
- over exposed vessels/organs/grafts
- any wound with a negative initial response
Signs of wound deterioration
- inc. periwound erythema
- periwound skin hypoxia
- repeated need for sharp/sx debridement
- inc. drainage or bleeding
- new infection/necrosis
- increased pain
- increased wound size
- new undermining/sinuses
What are the main components of NPWT
- suction device
- wound filler (foam or gauze)
- occlusive sheet cover
- tubing
- collection canister
Advantages of NPWT
- enhances wound healing
- continuous coverage wounds
- comfortable
- maintains optimal moist environment
- infrequent dressing changes
Disadvantages NPWT
- more expensive
- patient stuck to suction unit
- could cause skin irritation
- time consuming set up
- does not substitute hydrotherapy
What is the most common mode of delivery for NPWT - especially initially
continuous
What pressure is optimal for granulation tissue formation (NPWT)
125 mmHg
What ramping increment is used for NPWT pressure?
25 mmHg for pt comfort, wound response, treatment goals
How long should you wait to change NPWT dressings if it was over a fresh skin graft?
3-5 days to make sure the graft is stable first
When do you DC NPWT
- goals met
- granulation of wound bed even w/skin surface
- no benefit has been seen in 24 hrs
- signs of wound deterioration
- new infection
- pt intolerance
- sanguineous drainage fills canister in 1 hr or > 2 in 24 hrs
NPWT Application steps
- prep wound bed
- prep periwound w/topical moisture barrier/nonadherent gauze
- non-adherent protective leayer
- wound filler - occlusive sheeting 3-5cm past wound edge
- drain
7 connect tubing - set parameters
- turn on suction & confirm seal
- education
- document type and # of foam at each time
What are the wound healing benefits of US?
- inc local blood flow
- dec bioburden
- enhance all 3 phases of wound healing
- debridement
- pain reduction
US Theory
- cavitation (vibration of bubbles to cause compression forces)
-microstreaming (unidirectional mvmt of tissue fluids causing mechanical stim to surrounding cells)
When is cavitation stable vs unstable?
Stable: bubbles change size
Unstable: bubbles grow and then burst causing free radical foration
Indications for US
- traumatic wounds
- burns
- skin teras
- P injuries
- venous insufficiency
- diabetic foot ulcers
- inflammatory wounds
- split-thickness donor sites
- debridement
- pain reduction
- infection
What does US do in the inflamatory phase?
- degranulates mast cells to release histamine to attract neutrophils and monocytes to the injured area
What does US do in the proliferative phase
- stimulates fibroblasts to secrete collagen to accelerate wound contraction and increase strength of tissue
Precautions/Contra for US
- over epiphyseal plates
- over breast implants
- malignant tumor
- near a fetus
- laminectomy
- jt cement
- plastics for prosthetics
- pacemaker
- eyes
- carotid sinus
- over the heart
- absence of sensation
- acute inflam
- arterial insuff
- DVT
- osteomyelitis
Therapeutic use of high vs low frequency US
- High: tissue healing, repair & pain reduction
- Low: noncontact = tissue repair, wound cleansing, & pain reduction; contact = debridement
How to do direct application of high frequency US on a superficial/superficial partial thickness wound
- apply hydrogel sheet over wound
- apply US gel on sheet
- do US over hydrogel sheet
How to do direct application of high frequency US on a deep partial thickness/full thickness wound
- fill wound with hydrogel and remove air bubbles
- cover with film or hydrogel
- apply US gel on top
- US over it
How to do direct application of high frequency US over tunnels, tracts, undermining
- irrigate tunnels
- fill all open wound spaces w/hydrogel
- sonate over intact skin over targeted areas
Benefits of Low-f US
- cellular changes
- fluid mobilization
- dec. wound pain
- inc. cellular permeability
- bacterial killing
- relatively painless debridement
What is hyperbaric O2 Therapy
A patient inside a chamber breathes 100% O2 intermittently at a pressure higher than sea-level (b/t 2 & 3 ATA)
What are the physiologic effects of hyperbaric oxygenation
- vasoconstriction to tissues
- O2 delivery in the presence of arterial occlusion (Inc o2 of plasma can compensate to give O2 to tissue distal to occlusion)
- collagen deposition
- immune response
- mediate cytokine activity
- angiogenesis in irradiated tissues
How does hyperbaric O2 therapy help diabetic foot ulcers
- dec risk of major amputation and improve chance of healing at 1 yr
How does hyperbaric O2 therapy help arterial insufficiency ulcers
- lead to fibroblast prolif, collagen synthesis, angiogenesis and production of granulation tissue
Precautions of Hyperbaric O2
- COPD
- hx of spontaneous pneumothorax
- high fever
- optic neuritis
- claustrophobia & pregnancy
- HF
- uncontrolled HTN
- seizure disorders
Adverse effects of O2 under pressure
- middle-ear barotrauma
- sinus squeeze
- pulmonary barotrauma
- exacerbation of HF
- CNS: Cataracts or myopia
- claustrophobia
Why would you use UVC
UVC has a bactericidal effect causing cell death of bacteria and viruses
Contraindications for UVC
- acute eczema, dermatitis, or psoriasis
- cancer
- cardiac dis
- diabetes
- eyes
- hepatic dis
- herpes simplex
- hyperthyroidism
- pulm tuberculosis
- renal disease
- SLE
Precautions for UVC
- generalized fever
- malignant wounds for palliative care
- photosensitivity
- recent x-ray or other radiation
- hx of skin cancers
How to apply UVC
- protect eyes (pt and clinician)
- block surrounding skin completely
- hold UVC parallel and 1 inch from wound bed
- only need 30-60 sec of treatment
UVC parameters
- time: 30-60 sec (180 s max)
- 1 inch and parallel to wound bed
- daily for 5 days, then repeat if necessary
What is the whirlpool?
Non-selective hydrotherapy that can remove loosely adhered debris, bacteria, exudate, dressing residue, and topical agents
What is the APTA stance on whirlpools in wound care
Do not use them - they can predispose patients to bacterial cross contamination and damage fragile tissue
How long does a typical PLWS session last
15 to 30 minutes
is PLWS positive or negative pressure therapy?
Both in one
What does PLWS do (theory)
- wound cleansing
- debridement of slough
- loosen nonviable tissue
- reduce surface bacteria
- increase local perfusion
- stimulation of granulation tissue
What are the cellular effects of PLWS
- compression-decompression cycles on the tissues that mechanically dislodge bacteria/nonviable tissue/debris from the wound bed
- promotes tissue granulation
- facilitates local increased vasodilation
What is the safe psi according the the AHCPR for PLWS
4 to 16 psi
Indications for PLWS
- critically colonized wounds
- presence of: infection, necrotic tissue, mucinous exudate, undermining/tunnels/tracks
- traumatic wounds w/foreign debris
- open amputation sites
- stage III and IV pressure ulcers
Precautions PLWS
- anticoagulants/active bleeding
- poorly visualized wound spaces
- near: fistulas, visible wound beds, recent byprass grafts, LVAD drain lines
- over exposed bone or tendon
- facial wounds
- hypothermia (if using cool fluid irrigation)
What is the normal saline & temp for PLWS
- 0.9% at 37-38 degrees celcius
Frequency of PLWS
- daily: infected, heavily draining
- 2-3x/week OP w/mod-heavy drainage
- 1x/week OP w/min drainage and no infection
What are some infection considerations when doing PLWS
- bacteria can go up to 8 feet away from treatment site
- risk for fluid aerosolization and transport of bacteria
- cover all surfaces and lines/ports/other wounds & then disinfect after
- mask for pt and clinician
PPE for PLWS
- waterproof gown
- gloves
- face mask + splash shield or goggles
- hair cover
- shoe covers
T or F: irrigation collection canisters can be cleaned out and re-used after PLWS
FALSE - they are single use and should go in a biohazard waste container
How should patient be positioned for PLWS?
comfortable w/draping and waterproof drape underneath and laying so that excess irrigation from one area does not go to another open wound
Indications for E-stim
- Pressure, arterial, venous, and diabetic ulcers
- clean wounds w/decreased or stalled healing
Precautions for E-stim
- child < 3 yo
- skin irritation or burns under electrodes
- when sensation is impaired or absent
- skin irritation from ion shifts
Contraindications E-stim
- over known malignancy
- osteomyelitis
- metal
- electrical implant
- anterior/upper chest (heart) or so that current will flow through anterior neck/upper chest
- developing fetus
- active bleeding
- transcerebral
How much can ES increase wound healing by?
as much as 22% per week
Which phases of healing do you want to use negative electrodes?
positive?
- negative: proliferation (& inflammation if infection present)
- positive: epithelialization, remodeling, & inflammation (no infection)
What is direct electrode placement vs indirect?
- direct one: monopolar is in the wound bed w/a dispersive electrode
- indirect: straddles the wound w/bipolar application and a dispersive electrode
If you are doing debridement and e-stim, in which order should it be completed?
- debride then do e-stim
Depth of current penetration (increase/decrease) as distance between electrodes increases?
- Increases
