Contamination of a PACU can lead to complications in patients and adverse health consequences among hospital workers. Microorganisms such as bacteria and fungi pose serious threats to patients while long-term exposure to anesthesia gases like nitrous oxide and desflurane present significant risks to the health of nurses and anesthetists. Numerous academic, institutional, and governmental studies have demonstrated types of risks poor air quality can pose in PACUs [2-4].

Post-anesthesia care presents significant challenges to hospitals and their people as the health and safety of both patients and hospital workers can be at risk if conditions are not properly maintained. The United States’ National Institute for Occupational Safety and Health (NIOSH) [5] and Occupational Safety and Health Administration (OSHA) [6] reported on the potential harms of long-term exposure to anesthesia gases among OR workers. Nitrous oxide (N₂O) and halogenated gases may leak from a patient’s breathing circuit or they may be exhaled by patients recovering from anesthesia. NIOSH did not give a conclusive argument that long-term exposure to N₂O and halogenated gases like desflurane causes harm, but it made mention of the fact that several studies have linked such exposure to “miscarriages, genetic damage, and concern among operating-room workers”. While OSHA [6] has yet to set permissible limits for N₂O and halogenated gases in PACUs, it has provided guidance to other organizations which developed Recommended Exposure Limits (RELs).

NIOSH issued RELs for N₂O - 25ppm - and some halogenated agents - 2ppm [7]. Other professional organizations offered N₂O RELs of 50ppm. Italy, Sweden, Denmark, and the United Kingdom set N₂O RELs of 100ppm [8]. OSHA [6] reported acceptable tolerances for halothane at 50ppm, and 75ppm for enflurane. Some relevant publications rely on the 2ppm RELs for all halogenated agents [9], including desflurane even though desflurane was introduced long after NIOSH introduced the 2ppm standard [7]. NIOSH reported on the need for desflurane specific RELs [10]. A recent study reported desflurane RELs of 5ppm in Denmark, 10ppm in Sweden and Poland, and 20ppm in Austria [11]. There is no consensus REL for desflurane, NIOSH has not yet issued RELs for desflurane, and few studies have dealt with desflurane – one of the three halogenated agents most often used today, and the halogenated agent measured in this study at Rajavithi Hospital in Bangkok.

Few governments around the world have offered public guidance on safety limits for bacteria and fungi though studies singularly conclude that such contaminants contribute to postoperative complications, especially in patients with diabetes, weakened immune systems, and respiratory diseases [12]. Western Australia Department of Health (WADH) set a limit of 10 bacterial or fungal Colony Forming Units (CFUs) per cubic meter at the patient level [13]. United Kingdom Department of Health (UKDH) recommended bacterial and/or fungal limits of 10CFU/m³ within 300mm of a wound, and 180CFU/m³ for active OR ambient air [14]. Other countries have set limits of 50—150CFU/m³ for bacteria and fungi [15]. One study reported an acceptable threshold of airborne bacterial and/or fungal contamination in a general office environment of 500CFU/m³, which may suffice for the lobby of the hospital but not a PACU [16].

The European Agency for Health and Safety at Work (EU-OSHA) mentioned waste anesthetic gases posed a “relatively high” risk to healthcare workers [17]. According to EU-OSHA, communication with employees regarding health and safety issues like waste gas exposure is vital to both employer and employee. An article in the EU-OSHA magazine found inadequate training is the top threat to employee health and safety [18]. The article mentioned that because healthcare institutions often have many, varied, and complex machines, they must frequently develop their own understanding of risks and develop plans of action independently to satisfy their unique needs; employee engagement and feedback are critical to continuing success and improvement.

OSHA regulations grant employees the right to know about chemical hazards in their workplace [19]. In the United States, employers must also instruct employees on how to protect themselves against those hazards. The State of Minnesota’s OSHA (MN-OSHA) implements federal guidelines in three main parts-identification and labelling of hazardous substances, and employee training. MN-OSHA (2017) requires the hazard communication (HazCom) program to inform employees of hazardous substances; records must be retained; employee training must be frequent and documented [20]. Similarly, section 32 of Thailand’s Occupational Safety, Health, and Environment Act requires employers to conduct hazard assessments, study potential impacts of the working environment on employees, and prepare plans regarding occupational safety, health, and environment for both employees and supervisors [21].

Considering results of historical research, especially publications from governmental organizations [5, 6, 13, 14], Rajavithi undertook the project certain that installation of a new ventilation system would reduce airborne contaminants in the PACU. The research documents change in air quality in the PACU, and in doing so helps the hospital quantify the value of its capital investment. Legal and professional standards compel the hospital to continually make assessments, monitor data, train and retrain staff in attempts to improve the quality of care and safety in the working environment. As part of broader initiatives to improve the hospital, Rajavithi deployed a HazCom and training campaign and sought to estimate its impacts on PACU employees. Once again, hospital staff expected the campaign to produce positive results. The research documents change in PACU staff attitudes toward health and safety procedures, which helps Rajavithi and other healthcare professionals develop continued training and engagement programs as required by law, ethical codes, or professional standards.

Research regarding air quality in PACUs is available but not in abundance. PACUs are specialized niches of hospital systems, and they receive less attention than other domains in healthcare research. Publication concerning PACU standards and practices in Thailand is rare, which lends importance to this study. Research regarding the performance of a HazCom and training program is integral in a healthcare provider’s effort to raise standards in patient care alongside improved occupational health and safety. Thus, stakeholders in Rajavithi Hospital, other hospitals in Thailand, and those around the world may benefit from issues discussed herein and any future studies on related matters.

The utility of the ventilation system is determined by the level to which such systems reduce airborne contaminants (i.e. nitrous oxide, desflurane, bacteria, and fungi). The success of the HazCom and training program is primarily qualified by increases in perceived importance of health and safety behaviors among relevant hospital workers, and secondarily by decreases in airborne contaminants. The researcher assumes that demonstrated improvements in the Rajavithi Hospital PACU suggests that other hospitals in Thailand, and elsewhere, could benefit from implementing either or both ventilation systems and campaigns. Ultimately, positive results in this study could result in saving the lives of patients; better air quality and attentive staff will certainly aid in their recovery and improve working conditions for nurses and anesthetists.

The first question the research must answer is, “What are the concentrations of bacteria, fungi, desflurane, and nitrous oxide in the Rajavithi Hospital PACU?” Sections 2.2 and 2.4 provide details on the measurement of waste gases and microorganisms. After measuring the levels of atmospheric pollutants, the hospital installs a new ventilation system. Installation immediately following measurement allows the hospital to witness the direct, positive effect of the ventilation system, which provides benefits to patients whose air quality stands to improve.

The second research question is, “Does a HazCom and training program increase PACU worker attention to and concern for health and safety procedures?” The research answers this question with before and after surveys. Sections 2.2 through 2.4 give details of the instrument, participants, and sampling procedure. Following the completion of the informational campaign and second survey, measurements of atmospheric contaminants were taken a second time. Data confirm or disconfirm the first and second hypotheses.

Hypothesis 1: The new ventilation system decreases atmospheric pollution in the PACU.

Hypothesis 2: The hazard communication program increases perceived importance of health and safety procedures among PACU workers.

Rajavithi staff and administration created two simple surveys during the planning stages of the campaign. First, Rajavithi administration surveyed PACU workers, asking if they had experienced various symptoms (e.g. headache, rash, eye irritation) within the year prior. The survey asked participants if they had experienced such symptoms within the past year. “Yes” and “No” were possible answers. A preliminary health survey was administered in June 2016; the follow-up survey was conducted between January and February 2018.

Another survey assessed PACU workers’ attitudes toward health and safety procedures with a 5-point Likert scale where “1” was the lowest level of perceived importance and “5” was the highest. Hospital management administered the perceptions survey in June 2016 and the second April 25-30, 2017.

Waste anesthesia gas in the PACU atmosphere was measured using a TSI Velocicalc Multi-Function Ventilation Meter model 9565-P with a thermoanemometer articulated probe model 966. Atmospheric microorganism contamination was measured using a PBI International air sampler, model Duo SAS Super 360, with dishes for bacteria and fungi detection. The first measurements were taken in July-August 2016 prior to the campaign launch. A second sample was collected April 25-30, 2017.

At the time of the study, there were 64 PACU staff members, all of whom were participants. Participation in the survey was mandatory as per employment agreement clauses pertaining to ongoing monitoring, supervision, and training. Participants included 5 males and 59 females, of which there were 61 anesthesia nurses and 3 anesthetists. Mean age of participants was 40. Roughly 60 percent of participants had more than 5 years of experience in their position. No patients were involved in the study.

Rajavithi Hospital, in downtown Bangkok, is a 1,200-bed public medical center that can accommodate 40,000 in patients and 1,000,000 out-patients annually [22]. The hospital is staffed by more than 200 doctors, 800 nurses, and more than 4,000 supporting staff. The PACU located adjacent to 22 operating rooms and has an area of 98.02 square meters. Surveys did not request individual respondents to identify themselves. All staff members were able to deposit completed questionnaires discretely and confidentially. No special permission or paperwork was required to collect the data.

Self-reporting surveys always pose a risk of inaccurate or “socially-desirable” reporting, however, any false or misleading response would have violated standards of professional ethics.

An independent outside firm collected air samples and tested for excess anesthetic gas and microorganisms using the instruments listed in section 2.2.

Following initial air sample and survey collections, PACU staff and hospital administration held an exploratory meeting in September 2016, during which time they developed an outline for a hazard communication and training program. The plan consisted of three parts: (1) commissioning a team to inspect the PACU for machine and structural flaws (i.e. broken doors, leaking water pipes, malfunctioning ventilation fans), (2) managing regular inspection of anesthetic equipment (i.e. calibration, leak inspection, joint and junction inspection, etc.), (3) engaging PACU staff with an informational and training campaign.

In the initial worker health survey, 64 participants reported varying experiences with each of 13 symptoms. More than half of the participants had experienced a headache in the year prior to the survey. In the follow-up survey, the incidence of every symptom had noticeably decreased. Table 1 shows frequencies related to participant health symptoms.

Between the first and second survey, means increased and standard deviations decreased on all survey items. Thus, participants perceived all items to be of higher importance in the second survey compared to the first. Additionally, participants’ responses in the second survey were more uniform than in the first survey. When represented graphically, survey data were grouped more tightly around the high end of the scale in the second set as compared to the first.

Air samples revealed some contamination in the PACU. Moderate concentrations of N₂O were found in both stages of the study. Low concentrations of desflurane were found. Extremely high levels of bacteria were found in the first measurement, a level which fell to just above normal in the second stage. Fungal contaminants were found in moderate amounts. Levels of all four contaminants were lower in the second stage as compared to the first.

Ideally, every item on the survey should have received the maximum value for perceived importance. The survey item that received the lowest level of perceived importance in both stages was handwashing - a behavior that can serve to reduce the number of bacteria and fungi transferred from one area to another, both within the PACU and between the PACU and elsewhere in the hospital. Coincidentally, the behavior that participants reported the second lowest perceived importance was wearing a mask when treating a patient - a behavior that can help prevent infection from airborne bacteria or fungi. Handwashing and use of antibacterial gels are essential sanitation and hygiene habits among workers in the hospital generally, and especially in PACUs Table (2). While perceived importance is not an absolute indication of the likelihood that a worker engages in a behavior, hospital administration may consider this point to be the most significant finding in the study. Further reduction of contaminants may be available via more frequent hand sanitation.

Likewise concerning was the relatively large increase in perceived importance between surveys for items relating to changes of shoes during patient transfer, which suggested workers only became aware of its high importance, or overcame cognitive dissonance, after receiving consistent training and contact with information about the issue. Considering the relatively large increases in perceived importance for several other items on the survey, hospital administrators should investigate this item further.

Overall, the concentration of bacteria fell from a seriously contaminated level to one just above RELs for a hygienic space in the hospital. The researcher inferred that, while worker attitudes probably played a positive role in this reduction, most of this change was due to the installation of the ventilation system. Considering that concentrations at the end of the study were still on the high side, the researcher recommends hospital administration investigate installing additional ventilation while continuing to stress personal hygiene.

The item on the survey that showed the greatest increase between stages was regarding wearing the N95 mask when treating patients with respiratory diseases. This result demonstrated PACU workers’ concern for their health relating to potentially contagious diseases, but the lower levels of perceived importance of the other mask item may suggest workers are less concerned about potentially harmful effects of exposure to N₂O and desflurane. While N₂O levels were below established RELs, workers’ low perceived the importance of facemasks in comparison to other survey items should receive some attention to ensure worker health and safety (Table 3).

Little prior research was found regarding desflurane contamination, and this may be because desflurane is eliminated faster and therefore poses significantly less risk of toxicity due to long-term exposure when compared to older anesthetics like Halothane [26]. Desflurane is one-eighths as potent as Halothane, one-third as potent as Sevoflurane, and one-fifth as potent as isoflurane [27]. Desflurane concentrations at Rajavithi Hospital’s PACU were far below general the hospital’s in-house RELs for halogenated agents of 2ppm. One matter of concern for the research was that the hospital also uses sevoflurane in its ORs, but the administration did not approve monitoring and measurement of sevoflurane for the purposes of this study. Thus, even though desflurane levels are very low, it is still possible that hospital staff are exposed to harmful halogenated agents. Bearing that in mind, the researcher recommends Rajavithi Hospital should continue to monitor the PACU atmosphere for the detection and measurement of all anesthetic gases in use at the hospital, every six months as recommended by OSHA [6].

Hospital administrators were, and should be, pleased to witness declines in airborne pollutants in the hospitals’ post anesthesia care unit. The campaign was an apparent success, especially with regards to bacteria, but the success was limited given that N2O levels were within 20 percent of RELs while bacterial and fungal concentrations still exceeded several sources’ RELs at the end of the study. The positive results of the study demonstrate that contaminations levels can be significantly reduced over the course of months with the addition of a ventilation system, and by making efforts to ensure all personnel involved remain conscious of the importance of health and safety procedures. Like all surgical hospitals, Rajavithi should continue to monitor and measure air quality in the PACU, troubleshoot potential impediments to further reduction of pollutants, and devise new solutions such that air quality is maintained well under RELs for all gases and particulate matter.

A main concern for hospital administration presently is to continue monitoring, and to do so frequently, so they can avoid making hasty or unwarranted conclusions about the effectiveness of the ventilation system and information campaign. One aspect of the study that may have been overlooked is that levels of airborne bacteria and fungi are naturally affected by seasonal changes [28-30]. Rajavithi administration should consider the possibility that the lower bacteria and fungi count in the second sample was due in part to ambient temperature and humidity. Notwithstanding the possibility that some of the variation was due to weather, research at Thai hospitals previously found that occupant number is the primary source of airborne bacteria and fungi [30].

The single most important finding of this study was that microorganism contamination levels were higher than all recommended limits for hygienic spaces in a hospital environment. Whether these high contamination levels were due to practices among PACU workers, overcrowding in the hospital, substandard anesthesia scavenging equipment, or insufficient ventilation is yet unknown. Considering the high level of risk posed by air pollution in PACUs, to both workers and patients, Rajavithi Hospital should continue to assess equipment and ventilation systems. Hospital administration and donors may need to make room in the budget for new and improved gas scavenging and ventilation equipment.

Air quality is an issue of importance in all hospitals; and given that Rajavithi Hospital successfully implemented technology and an informational program which led to reduction in airborne pollutants in a hygienic zone, this research can be helpful to other hospitals in Thailand and elsewhere around the world. OSHA [6] has promoted HEPA ventilation systems and HazCom programs for years, so the concepts are nothing new; but, by demonstrating their effectiveness in Thailand through this study, Thai hospital workers should be persuaded. Given that Rajavithi is a government hospital, the results of this study can easily be transmitted through the Ministry of Health to hundreds of other public hospitals. Dissemination of findings, in combination with continued research and monitoring, should further promote the issue of PACU hygiene and thereby improve recovery of patients, health and safety conditions for all persons in the PACU.