How Many Airborne Particles Emitted from a Nurse will Reach the Breathing Zone/Body Surface of the Patient in ISO Class-5 Single-Bed Hospital Protective Environments?—A Numerical Analysis

Abstract

We conducted a numerical simulation to quantify the number of particles emitted from a nurse that will enter the breathing zone or reach the body surface of a patient during patient care in an ISO Class-5 single-bed protective environment. Nurses may be the most likely source of infection for patients in this environment as they are typically single-bed rooms and visitors are forbidden. Four scenarios representing common nurse-patient interactions in a hospital protective environment were analyzed: a nurse standing next to a reclining patient; a nurse leaning over a reclining patient; a nurse standing next to an upright sitting patient and a nurse learning over an upright sitting patient. We applied computational fluid dynamics (CFD) methods to solve the governing equations of air flow, energy, and dispersion of different-sized airborne particles. We also carried out full-scale measurements in a hospital-based ISO Class-5 protective environment to validate simulations and determine the probability that particles emitted from the nurse's body will enter the patient's breathing zone or reach the patient's body surface. Our results indicate that particle dispersion is greatly influenced by the protective environment's downward air flow pattern. Particles from the body of a standing nurse seldom reach the patient, whereas particles are more likely to contact the patient in cases where the nurse is leaning over the patient. These results are useful for developing best practices for preventing cross-infection during patient care, particularly among immunocompromised patients.

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