Inhaling airborne particles can put both critical patients and healthcare staff at risk for detrimental health issues. Controlling these particles is necessary for protecting both staff and occupants of nearby rooms from exposure to infectious particles. To maintain safety in a hospital, it is crucial to monitor both differential pressure and particle counts in anterooms.

Critical environments can have a variety of layouts depending on the purpose of the space. Frequently, these critical environments will have a multi-room setup. Some examples of a multi-room setup are an isolation room and anteroom or a cleanroom, gown up room, and clean storage area.

Requirements and regulations are becoming ever more stringent for critical environments, making finding the right products for a space increasingly difficult. Not only must the specs of the product be considered, but the supplier must be taken into account as well. Shopping around with the intent to purchase from a variety of vendors takes a significant amount of time and effort. In addition to wasted time and effort, buying from multiple vendors comes associated with a number of risks and drawbacks, including:

• Incompatible hardware
• Incompatible software
• Minimal or disjointed tech support
• Inability to integrate products
• Installation and operational issues

Hot-wire anemometers are widely used throughout hospitals. Although their initial accuracy remains undisputed, a hot-wire anemometer's accuracy is not stable over time. Hot-wire anemometers must be cleaned at regular intervals to remain an accurate and effective solution for monitoring room pressure. Without regular cleaning and calibration, the accuracy of a hot-wire anemometer decreases significantly over time.

Proper room pressure and airflow are crucial for maintaining critical environments in hospitals. When talking about pressurized hospital spaces, the most well-known are operating rooms and isolation rooms. However, these are not the only two pressurized spaces within a hospital. ASHRAE Standard 170 details 60 different types of rooms in a hospital requiring pressurization. Without proper room pressurization, hospitals put their accreditation by the Joint Commission in jeopardy.

In a hospital environment, alarm fatigue is an increasingly prevalent issue. Alarm fatigue is the sensory overload when clinicians are exposed to an excessive number of alarms; this can result in staff ignoring alarms, particularly if different devices employ similar sounds or frequencies. Nuisance alarms are those not representative of a patient in danger but come from devices that don't allow configuration for non-critical circumstances.

Twice a year, many critical environments - such as compounding pharmacies and cleanrooms - undergo particle certification. To obtain room certification, either a minimum sample volume (as written in the EC GMP Annex 1) should be taken, or the sequential sampling technique (as identified in both FS209E and ISO 14644-1) should be used. However, since this particle certification usually occurs only every six months, many critical environments are unaware of their particle counts during the remainder of the year.

Flow rate is important to consider when selecting a particle counter for a critical environment. The flow rate of a particle counter is the rate at which a pump draws air through the sample chamber, measured in cubic feet per minute (cfm). Two common flow rates for particle counters are 1 cfm and 0.1 cfm. Depending on the application, each flow rate can be valuable.

Compliance with USP 797 and USP 800 are critical for maintaining a sterile cleanroom for CSPs. Proper environmental conditions, as outlined by USP 797 and USP 800, help to ensure the effectiveness and quality of medications.

USP 797 is the standard in place governing the sterile preparation of compounded pharmaceuticals. USP 797 covers the compounding of both hazardous and nonhazardous drugs with a focus on the protection of sterile compounds and environments from contamination. This standard is in place to ensure patient safety and reduce risks associated with compounding pharmaceuticals, including contamination, infection, and incorrect dosage. The standard helps to guarantee patients receive quality drugs free from contaminates. This standard applies to all pharmacies that produce compounded sterile preparations (CSPs); this includes pharmacies within hospitals, radio or nuclear pharmacies, chemo units, and operating rooms. The goal of the standard is to prevent harm to patients resulting from microbial contamination, bacterial endotoxins, variation in the strength of ingredients, and chemical and physical contaminates.