Rescue Litter (Basket Stretcher) Product

Overview

A rescue litter, commonly called a basket stretcher or Stokes litter, is a rigid patient transport device designed to stabilize and protect an injured or immobilized person during extraction from difficult terrain, vertical rope systems, or hazardous environments. The device consists of a rectangular frame of aluminum or steel tubes, a drainage-capable mesh floor, an integrated rope-attachment bridle system, and body restraint straps. Unlike soft-frame stretchers, the rigid litter maintains patient alignment during tilt, rotation, and rough handling, making it essential in mountain rescue, cave rescue, swift-water operations, and helicopter evacuation.

The fundamental design feature is the four-point Lift Bridle that distributes load equally to all corners of the Frame Structure, preventing frame bending and tipping during vertical haul. The perforated Mesh Shell allows water drainage and visibility of the patient, while the Restraint System keeps the patient centered and prevents rolling during transport.

Frame Architecture

Structural Design

The Frame Structure consists of two long parallel [[rescue-stretcher-litter-long-beam|long beams]] (2000–2200 mm) connected by four [[rescue-stretcher-litter-cross-beam|cross beams]] spaced roughly 400–500 mm apart. Cross beams at the head and foot provide attachment points for the bridle runners, while intermediate beams maintain mesh span and prevent sagging. All beam-to-beam joints are reinforced with [[rescue-stretcher-litter-corner-gusset|corner gussets]], creating a rigid box structure resistant to bending moment.

Aluminum 6061-T6 is preferred for weight reduction (9–12 kg total) and corrosion resistance. Galvanized steel litters weigh 12–15 kg but offer superior impact resistance and are used in high-volume commercial rescue services. Tube diameter (typically 25–32 mm OD, 1.6 mm wall) is engineered to support a 250–350 kg patient load plus dynamic shock loads during helicopter insertion or rocky impacts.

Mesh and Drainage

The Mesh Shell spans the interior perimeter of the frame and serves dual purposes: patient support and drainage. Perforated HDPE or stainless steel mesh (3–5 mm hole diameter) allows water, blood, and mud to drain below the patient. Below the mesh, a removable Drainage Insert acts as a splitter and hygiene barrier. The mesh edges are bound with reinforced [[rescue-stretcher-litter-mesh-splice|splices]] and riveted to the frame at multiple points to prevent tears under load.

Load Distribution and Bridle System

The Lift Bridle is critical to safe vertical operation. Four separate [[rescue-stretcher-litter-bridle-runner|bridle runners]] (one at each corner) are stitched or riveted to the frame, each rated for 600+ kg individual load. These runners connect to a central distribution ring or are clipped with carabiners to a single main rope. The geometry distributes load evenly, so no single corner bears excessive bending. In four-point bridle mode, a 250 kg patient plus gear results in 62.5 kg per corner—well within design margins.

The bridle webbing is typically 40–50 mm nylon, rated for 2400+ kg tensile strength. Stitching uses reinforced cross-patterns and is often backed with adhesive-bonded webbing to prevent slipping. All attachment points undergo periodic inspection in rescue operations, as fraying or rotting webbing is a known failure mode.

Patient Restraint System

The Restraint System employs three main webbing straps:

1. Chest Strap: Crosses the torso just below the armpits.
2. Waist Strap: Secures across the abdomen and pelvis.
3. Leg Strap: Wraps around thighs or feet, preventing lower-body movement.

Each strap is equipped with dual-sided [[rescue-stretcher-litter-quick-buckle|quick-release buckles]] allowing rapid fastening and unfastening with gloved hands. The webbing is typically padded with [[rescue-stretcher-litter-padding-foam|closed-cell foam]] to distribute pressure and improve patient comfort during extended transport. Straps are designed to prevent over-tightening, which can restrict breathing or worsen spinal injuries.

Protective Hardware and Handles

[[rescue-stretcher-litter-corner-hardware|Corner bumpers]] molded from rubber or stiff plastic are fixed to all four frame corners and edges. These absorb impact when the litter strikes rock, tree, or helicopter fuselage, protecting the mesh and frame from deformation. [[rescue-stretcher-litter-carry-handles|Carry handles]] (two or four, depending on design) along the long edges allow manual portage across short distances or during ground transport. Handles are often left bare aluminum or wrapped with foam for weather and grip comfort.

Materials and Standards

The Frame Structure is typically 6061-T6 aluminum with 1.6–2.0 mm wall thickness, or galvanized structural steel (ASTM A500). The mesh is virgin HDPE or stainless steel 304. Fasteners are stainless steel (A4-70) to resist corrosion from saltwater, blood, and sweat. Webbing is military-spec nylon (1000 D minimum), and foam padding is closed-cell EVA or neoprene rated to −20°C and above.

Rescue litters must meet EN 1789 (ambulance equipment standards) or NFPA 1999 (rescue equipment). Testing includes static load of 250 kg applied at the center, drop tests from 1 m onto concrete, and bridle load tests to 2400 kg (per runner).

Operating Principles

1. Ground Transport: Patient is positioned supine (or per injury protocol), restrained with all three straps, and carried by teams of two to four rescuers using handles.

2. Rope System Deployment: The four bridle runners are clipped to carabiners or directly to a main rope. The litter is hoisted or lowered on fixed ropes, with an additional tag line preventing rotation.

3. Aerial Evacuation: The litter is loaded into a helicopter net or cage with additional tie-downs. The rigid frame prevents patient ejection or collision with frame edges during rotor wash and landing.

4. Rough Terrain: The rigid mesh and frame allow the litter to be dragged over rocks, roots, and steep slopes without collapsing or pinching the patient.

Variations and Specialized Designs

• Cave Rescue Litter: Narrower (550 mm internal width) to fit through tight passages; sometimes made from composite materials for reduced weight.
• Swift-Water Rescue Litter: Equipped with quick-drain design and submersible bridle attachment; often used with throwline systems.
• Toboggan-Style Litter: A hybrid with curved skids for sledding down snow-covered slopes, popular in alpine and backcountry rescue.