Pulsed Lavage with Suction (PLWS)

Pulsed Lavage with Suction (PLWS)

• A debridement/cleansing modality which delivers pulsed irrigation at a controlled PSI with suction
• Removes contaminated irrigation fluid
• Combines positive pressure (fluid irrigation)
• Combines negative pressure (suction) to enhance wound healing

Indications

• PLWS is beneficial for critically colonized wounds
• PLWS is beneficial for wounds with decreased or stalled granulation tissue
• PLWS is beneficial for infected or necrotic wounds
• PLWS is beneficial for wounds with thick or mucous-like exudate
• PLWS is beneficial for wounds that exhibit undermining, tunneling, or sinus tracts
• PLWS is beneficial for open amputation sites
• PLWS is beneficial for traumatic wounds containing foreign debris
• PLWS is beneficial for stage 3 and 4 pressure ulcers

Effects & Benefits

• Debridement: Loosens nonviable tissue
• Reduces bacteria (bioburden)
• Increases local perfusion
• Stimulates granulation tissue formation

PLWS Parameters

Irrigation Pressure

• 4-6 psi: For sensitive areas (initial treatment, anticoagulation therapy, fragile wounds, intense pain)
• 8-9 psi: To decrease bacterial load
• 9-15 psi: For removing debris in non-infected wounds
• 2 psi: For tunnels and tracts

Suction Pressure

• 60-80 mmHg: For painful wounds or wounds that bleed easily
• 80-100 mmHg: For removing exudate and necrotic tissue

Temperature of Irrigation Fluid

• 37-38°C to prevent hypothermia and facilitate vasodilation

Frequency & Duration

• Infected wounds: Twice daily if possible
• General cleansing and stimulation: Daily or every other day
• Discontinue if no improvement after 1 week

PPE & Infection Control

• Aerosolization Risk → Full PPE required
• Hair cover, face shield/mask/goggles, waterproof gown, shoe covers, gloves
• Sterile field around the wound must be maintained
• Handpieces can be reused for the same patient but must be sterilized
• Divertor tip should not be reused

Precautions

• Anticoagulant therapy or active bleeding
• Poorly visualized wound spaces
• Near visible blood vessels, exposed tendons/bones
• Near recent surgical closures or bypass grafts
• Facial wounds
• Risk of hypothermia with cool fluid irrigation

Ultrasound (US) in Wound Healing

Indications

• Diabetic ulcers
• Pressure injuries
• Venous insufficiency wounds
• Traumatic & surgical wounds
• Wounds needing debridement (contact LFUS)
• Pain reduction (thermal & nonthermal application)

Cavitation

• Stable cavitation enhances cellular activity
• Unstable cavitation liquefies necrotic tissue and fragments microorganisms

Acoustic Streaming

• Alters cell membrane permeability, leading to increased protein synthesis, improved immune response, and macrophages producing more growth factors

Types of Ultrasound

High-Frequency Ultrasound (HFUS)

• Rarely used in wound care
• Can increase periwound tissue temperature for vasodilation and pain reduction
• Continuous mode (1-3 MHz): Thermal effect; may cause burns if blood flow is insufficient
• Pulsed mode: Safer, providing nonthermal effects

Low-Frequency Ultrasound (LFUS)

• Primary method for wound management
• 40 kHz, low intensities (0.1-0.5 W/cm²)
• Promotes wound healing via tissue stimulation
• Enhances fibrinolysis
• Removes bacteria and exudate
• Actively kills bacteria by damaging cell walls
• Contact LFUS: Selective debridement
• Noncontact LFUS (MIST Therapy): Higher cavitation effects for bacteria removal

Ultrasound Precautions & Contraindications

• General ultrasound precautions apply
• Contraindications include acute infections and osteomyelitis
• Active/profuse bleeding is a contraindication
• Severe arterial insufficiency (No thermal US) is a contraindication
• Deep vein thrombosis (DVT) is a contraindication
• Necrotic wounds are a contraindication
• Acute inflammation (No thermal US) is a contraindication

Electrical Stimulation (E-Stim) in Wound Healing

Mechanism

• Restores bioelectrical signals in the wound
• Affects cell migration, function, and polarity
• Increases blood flow
• Decreases edema and bacterial load
• Stimulates autolytic debridement

Indications

• Pressure injuries, venous/arterial wounds
• Traumatic, surgical wounds
• Ischemic wounds, donor sites, wound flaps
• Burns
• Clean but stalled wounds

Phases of Healing & E-Stim Effects

• Inflammatory Phase: Neutrophils (-) & Macrophages (-) respond to positive charge → Increased migration & debridement
• Proliferation Phase: Fibroblasts (+) respond to negative charge → Increased collagen deposition & faster contraction
• Epithelialization: Epithelial cells (-) respond to positive charge → Enhanced migration across the wound
• Maturation Phase: Mast cells (+) respond to positive charge → Reduces excess scarring

Types of Electrical Currents

• Direct Current (DC) & Pulsed Current (PC)
• DC is used for wound healing
• PC = Intermittent pulses for a more comfortable application
• High-Voltage Pulsed Current (HVPC) is monophasic, with short pulse duration (5-20 µs), and high voltage (75-150 V)
• Most evidence supports HVPC use in wound healing
• Low-Voltage Pulsed Current (LVPC) is monophasic or biphasic, with longer pulse duration & lower voltage

Application Techniques

• Direct (Monopolar): Active electrode placed directly in the wound bed, dispersive electrode placed elsewhere to complete the circuit
• Indirect (Bipolar/Straddling): Two active electrodes of same polarity placed opposite sides of the wound, with saline & insulating dressing used

E-Stim Parameters

• Voltage (Intensity)
• Polarity (Positive/Negative)
• Pulse Duration: 20-132 microseconds
• Frequency: 100-128 pps
• Treatment Duration: 45-60 min/day, 5-7 days/week

Precautions & Contraindications

• Children <3 years
• Skin irritation, burns
• Areas with impaired sensation
• Contraindications include osteomyelitis and cardiac pacemakers
• Malignancy is a contraindication
• Over carotid sinus, phrenic nerve, metal-containing topicals are contraindications