AORN guidance statement: human and avian influenza and severe acute respiratory syndrome

AORN Journal, August, 2006

I. OVERVIEW

A. INTRODUCTION

ASSUMPTIONS

The AORN guideline on human and avian influenza and severe acute respiratory syndrome (SARS) is based on research and the experience of health care workers. It is assumed that ongoing research will result in new knowledge, procedures, and medical and nursing interventions for the treatment of patients with human and avian influenza and SARS. This guideline is designed to assist perioperative registered nurses in creating and maintaining an optimal health care environment for patients with human and avian influenza and SARS. The guideline defines the unique physical and psychosocial needs of the influenza and SARS patient populations and presents guidance for establishing a plan of care for these patients.

B. HUMAN AND AVIAN INFLUENZA

During the twentieth century, influenza took an enormous toll on human life. More than four pandemics occurred.

* The 1918-1919 pandemic (ie, the "Spanish flu") caused an estimated 20 million to 50 million deaths worldwide. In the United States alone, there were 500,000 deaths.

* The "Asian flu" caused 60,000 deaths in the United States in 1957-1958.

* The "Hong Kong flu" pandemic of 1968-1969 caused approximately 40,000 deaths in the United States.

* The pandemic of 1977 (ie, the "Russian flu") had low mortality. (1-3)

During the last decade of the twentieth century, although there were no influenza pandemics, influenza-related deaths increased to 36,000 per year in the United States. During periods of epidemics, this number increased to 40,000. Influenza continues to be the sixth leading cause of death in the United States. For those over the age of 65, it is the fifth leading cause of death. (4)

Looking at the first five years of the twenty-first century, it is clear that the incidence of human influenza is not declining. The emergence of avian influenza as a potential threat to humans has become significant, making the threat of a future pandemic from avian influenza very real. (1)

DEFINITIONS

For the purposes of this document, the following definitions apply.

Antigenic drift: Point mutations leading to changes in antigenicity of the major hemagglutinin (HA) and neuraminidase (NA) antigen subtypes of an influenza virus. (5)

Antigenic shift: Change in circulating major antigen (ie, HA, NA) determinants either through exchange and reassortment of genetic material or adaptation to human transmission. (5) Occasionally, the antigenic shift that occurs with the influenza A virus is an abrupt, major change in the virus. (6)

Hemagglutinin: One of the two major surface proteins of the influenza virus. Important for virus attachment to cells of the respiratory epithelium. Subtypes include H1 to H15. The only described determinants involved in sustained human-to-human transmission are H1, H2, and H3. (2)

Influenza epidemic: A seasonal outbreak of influenza viruses that are already in existence among humans. (2)

Influenza pandemic: A global outbreak of disease that occurs when a new influenza A virus emerges in the human population, causes serious illness, and then spreads easily from person to person worldwide. Influenza pandemics are caused by a new subtype or by subtypes that have never circulated among humans or that have not circulated among humans for a long period of time. (2)

Neuraminidase: One of the two major surface proteins of the influenza virus that are less important for attachment but probably are important for propagation and virulence (ie, subtypes N1 to N9). (5)

HISTORY

Hippocrates (470 BC to 410 BC) described the first case of influenza-like illness. (1) The first recorded influenza pandemic occurred in 1580 AD and spread from Europe to Asia and Africa. During the seventeenth century, local epidemics were reported. In the eighteenth century, three known pandemics occurred, in 1729-1730, 17321733, and 1781-1782. In the nineteenth century, three pandemics occurred, in 1830-1831, 18331834, and 1889-1890. The pandemic of 1889-1890, known as the Russian flu, killed approximately one million people. It spread throughout Europe, reaching North America in December 1889 and spreading to Latin America and Asia in 1890. (3)

The most devastating influenza pandemic in recent history (ie, the "Spanish flu") occurred in the twentieth century. Worldwide, the death toll is estimated between 20 million and 50 million people and may have been as high as 100 million. In the United States, the mortality rate was more than 500,000 people. The Spanish flu was caused by the influenza A (H1N1) strain. It most likely originated in the United States and spread to Europe. The Asian flu of 1957-1958 was caused by the influenza A (H2N2) strain and had a mortality rate of approximately one million people worldwide. The virus was first identified in China. In 1968-1969, the Hong Kong flu, which was caused by the influenza A (H3N2) strain, had an estimated mortality rate in the United States of 40,000. Unlike seasonal influenza, influenza epidemics are particularly hard on people over the age of 65. At least initially, all three of these pandemics were characterized by a shift in age distribution of deaths to the population younger than age 65. (3)