Influenza

Elective surgery timing - Active influenza is a reason to postpone. Acute airway infection drives a significant rise in intraoperative and postoperative respiratory complications and hypoxia. Push harder toward cancellation when the plan calls for an endotracheal tube, or the patient has a history of airway reactivity, prematurity, or passive smoke exposure.

When to proceed anyway - Surgical emergencies, recurrent mild upper respiratory symptoms, and cases where the infection itself is the indication can reasonably go forward. Logistics matter too — a long trip to the facility or real financial hardship is a legitimate part of the calculus.

Gauge severity before induction - Room-air SpO2, work of breathing, and auscultation for wheeze and crackles. Severe cases progress to dyspnea, tachycardia, and hypotension within 48 hours of symptom onset, so a patient who looked well yesterday may not be the same patient today.

Secretions and a raw tracheobronchial tree - Expect copious mucopurulent secretions and an irritable airway on instrumentation. Have suction set up before you touch the airway, and prefer the least stimulating airway the case allows.

Antiviral therapy - Oseltamivir gives maximum benefit started within 48 hours of symptom onset, but for severe illness or a patient at risk of complications, start it regardless of how long symptoms have been present. ICU and immunosuppressed patients may need a prolonged course.

Oseltamivir in organ dysfunction - First dose is 75 mg for a patient of normal body mass, with subsequent doses reduced by the degree of renal impairment. It is not recommended in severe hepatic impairment (Child-Pugh C), where exposure rises roughly sixfold.

Secondary bacterial pneumonia - The organisms found at autopsy in fatal cases are Streptococcus pneumoniae, Streptococcus pyogenes, Staphylococcus aureus including community-acquired MRSA, and Haemophilus influenzae. A worsening picture on antivirals alone is a bacterial coinfection until proven otherwise.

Fulminant respiratory failure - Influenza ARDS is managed with noninvasive or invasive mechanical ventilation, and severe cases have required ECMO. Predictors of death are chronic lung disease, obesity, underlying neurologic disease, and delayed admission.

Watch for invasive fungal superinfection - Severe influenza is a recognized setup for invasive aspergillosis. New hemoptysis or worsening infiltrates in a ventilated influenza patient should raise it.

Pregnancy - Pregnant and postpartum patients are at increased risk of serious complications, including late pregnancy loss and reduced mean birth weight. The CDC recommends treatment and prophylaxis with oseltamivir or zanamivir by viral strain.

Protect the room - Direct contact and droplet spread are the predominant routes. Patients are infectious from a day before symptoms until 5 to 7 days after, so the asymptomatic-yesterday patient in your OR was already shedding.

Influenza is an orthomyxovirus infection of the upper and lower respiratory tract. Types A and B drive the annual seasonal epidemics. Hemagglutinin binds respiratory epithelial cells and lets the infection progress; neuraminidase cleaves the virions free to spread. The virus replicates in both upper and lower passages, peaking around 48 hours after inoculation.

What matters at the board is what it does to the airway lining. The trachea and bronchi become red and inflamed with mucopurulent discharge, and the pseudostratified epithelium desquamates down to an inflamed basal layer. That denuded mucosa is a reactive airway waiting for a tube.

In high-risk hosts — chronic lung disease, cardiac disease, pregnancy, immunocompromise, the very young and the elderly — it progresses to primary viral pneumonia, secondary bacterial pneumonia, hemorrhagic bronchitis, and ARDS, sometimes within 48 hours of the first symptom.