HKIE Professional Assessment - Biomedical Discipline flashcards

31 cards. Read the term and the definition here. The deck at the top of this page is optional.

Stress and strain

Stress is force per unit area (Pa); strain is fractional change in length. The slope of the linear stress-strain region is the elastic modulus, a key implant design parameter.

Wolff's law

Bone remodels in response to mechanical load, aligning trabeculae along principal stress directions. Engineers use this to design implants that avoid stress shielding and bone resorption.

Poiseuille flow

Laminar flow rate through a tube is proportional to the fourth power of radius and pressure gradient, and inversely to viscosity and length. Small lumen reductions cause large flow drops.

Foreign body response

Implanted materials trigger protein adsorption, neutrophil and macrophage activity, giant cell formation, and fibrous encapsulation. Surface chemistry and topography influence the response.

Nyquist criterion

Sampling frequency must be at least twice the highest signal frequency to avoid aliasing. Anti-alias filters must attenuate higher-frequency components before the ADC.

ECG bandwidth

Diagnostic ECG requires 0.05–150 Hz bandwidth and at least 500 Hz sampling. Monitoring ECG may use 0.5–40 Hz, which distorts ST segments.

Defibrillation energy

Stored energy in a defibrillator is E = ½CV². Monophasic shocks use 200–360 J; biphasic shocks use lower energy, typically 120–200 J, with comparable efficacy.

Patient leakage current

IEC 60601-1 limits patient leakage current in normal condition to 10 µA for type CF applied parts and 100 µA for type B and BF applied parts.

Acceptance testing

Verification that a newly delivered device meets manufacturer specification and purchase requirements before clinical use. Results are recorded in the equipment history file.

Preventive maintenance interval

PM frequency is set by manufacturer recommendation, equipment risk score, utilisation, and incident history. Typical intervals are 6 or 12 months for clinical devices.

MTBF and MTTR

Mean time between failures is total operating time divided by failure count. Mean time to repair is total repair time divided by repair count; both are HTM performance indicators.

ISO 14971 risk process

Risk management identifies hazards, estimates and evaluates risk, applies controls in a hierarchy, evaluates residual risk, and monitors production and post-production information.

IEC 62304 safety classes

Software safety class A means no injury is possible, B means non-serious injury is possible, and C means death or serious injury is possible. Class drives lifecycle rigour.

HK MDACS

The Medical Device Administrative Control System is Hong Kong's voluntary listing scheme, administered by the Medical Device Division of the Department of Health, covering devices and traders.

Pan-Tompkins algorithm

A QRS detection method using band-pass filtering (5–15 Hz), differentiation, squaring, moving-window integration, and adaptive thresholding to locate heartbeats in ECG.

Hounsfield unit

HU = 1000 × (µ_tissue − µ_water)/µ_water. Water is 0 HU and air is approximately −1000 HU; it standardises CT attenuation across scanners.

CMRR

Common-mode rejection ratio is 20 log₁₀ of the differential gain divided by common-mode gain. High CMRR rejects interference such as mains pickup in biopotential recording.

HL7 FHIR

A RESTful interoperability standard using resources such as Patient, Observation, and DiagnosticReport. It supports modern web APIs and is increasingly used alongside HL7 v2.

PDPO six principles

Hong Kong's Personal Data (Privacy) Ordinance sets six Data Protection Principles covering purpose, accuracy, retention, security, openness, and access/correction rights.

PPV and prevalence

Positive predictive value depends on disease prevalence. A highly specific test can still have low PPV when prevalence is low, which matters for screening decisions.

Tissue engineering triad

Successful tissue engineering combines cells, a scaffold that supports structure and degradation, and biochemical or mechanical signals to guide tissue formation.

Scaffold porosity

Interconnected porosity of roughly 70–90% with pore sizes around 100–500 µm supports cell infiltration, vascularisation, and bone ingrowth in orthopaedic scaffolds.

GMP cell processing

Cell and tissue products require validated aseptic processing, often in ISO 5 cleanrooms, with chain of identity and custody and release testing before clinical use.

Duty of care

Engineers must act within their competence and prioritise public safety. When a task exceeds expertise, they must refer to a qualified specialist and document the decision.

Conflict of interest

Financial or personal interests that could bias professional judgement, such as vendor gifts or shares in a supplier, must be declared and managed under employer policy.

Earned value CPI

Cost performance index is earned value divided by actual cost. A CPI below 1 indicates cost overrun; SPI below 1 indicates schedule delay.

Healthcare facility interfaces

Medical gas, essential electrical supply, HVAC pressure regimes, shielding, and IT segregation must be coordinated with clinical equipment planning during design and commissioning.

Whole-life carbon

Embodied carbon from manufacture, transport, and disposal plus operational carbon from energy and consumables. Single-use devices often dominate the footprint of a procedure.

AI as a medical device

Machine-learning software intended for diagnosis or treatment is regulated as software as a medical device, requiring validation, change control, and post-market performance monitoring.

Galvanic corrosion

Contact between dissimilar metals in an electrolyte creates a galvanic couple that accelerates corrosion. Implant designs avoid mixing stainless steel and titanium components.

Oscillometric NIBP

Cuff pressure oscillations are analysed to estimate mean arterial pressure, from which systolic and diastolic values are derived using an algorithm. Motion reduces accuracy.