Continuous monitoring of aerial bioburden within intensive care isolation rooms and identification of high-risk activities

Background

The spread of pathogens via the airborne route is often underestimated, and little is known about the extent to which airborne microbial contamination levels vary throughout the day and night in hospital facilities.

Aims

To evaluate airborne contamination levels within intensive care unit (ICU) isolation rooms over 10–24-h periods in order to improve understanding of the variability of environmental aerial bioburden, and the extent to which ward activities may contribute.

Methods

Environmental air monitoring was conducted within occupied and vacant inpatient isolation rooms. A sieve impactor sampler was used to collect 500-L air samples every 15 min over 10-h (08:00–18:00 h) and 24-h (08:00–08:00 h) periods. Samples were collected, room activity was logged, and bacterial contamination levels were recorded as colony-forming units (cfu)/m³ air.

Findings

A high degree of variability in levels of airborne contamination was observed across all scenarios in the studied isolation rooms. Air bioburden increased as room occupancy increased, with air contamination levels highest in rooms occupied for the longest time during the study (10 days) (mean 104.4 cfu/m³, range 12–510 cfu/m³). Counts were lowest in unoccupied rooms (mean 20 cfu/m³) and during the night.

Conclusion

Peaks in airborne contamination were directly associated with an increase in activity levels. This study provides the first clear evidence of the extent of variability in microbial airborne levels over 24-h periods in ICU isolation rooms, and found direct correlation between microbial load and ward activity.

Sepsis caused by bloodstream infection in patients in the intensive care unit: the impact of inactive empiric antimicrobial therapy on outcome

BACKGROUND

Sepsis is one of the leading causes of death in the UK.

AIMS

To identify the rate of inactive antimicrobial therapy (AMT) in the intensive care unit (ICU) and whether inactive AMT has an effect on in-hospital mortality, ICU mortality, 90-day mortality and length of hospital stay. A further aim was to identify risk factors for receiving inactive AMT.

METHODS

This was a retrospective observational study conducted at Glasgow Royal Infirmary ICU between January 2010 and December 2013. In total, 12,000 blood cultures were taken over this time period, of which 127 were deemed clinically significant. Multi-variate logistic regression was used to identify risk factors independently associated with mortality. Univariate analysis followed by multi-variate analysis was performed to identify risk factors for receiving inactive AMT.

RESULTS

The rate of inactive AMT was 47% (N = 60). Multi-variate analysis showed that receiving antibiotics within the first 24h of ICU admission led to reduced mortality [relative risk 1.70, 95% confidence interval (CI) 1.19-2.44]. Furthermore, it showed that severity of illness (as defined by SIRS criteria sepsis vs septic shock) increased mortality [odds ratio (OR) 9.87, 95% CI 1.73-55.5]. However, inactive AMT did not increase mortality (OR 1.07, 95% CI 0.47-2.41) or length of hospital stay (53.2 vs 69.1 days, P = 0.348). Fungal bloodstream infection was found to be a risk factor for receiving inactive AMT (OR 5.10, 95% CI 1.29-20.14).

CONCLUSION

Mortality from sepsis is influenced by multiple factors. This study was unable to demonstrate that inactive AMT had an effect on mortality in sepsis.

Meticillin-resistant Staphylococcus aureus in the intensive care unit: its effect on outcome and risk factors for acquisition

BACKGROUND

Meticillin-resistant Staphylococcus aureus (MRSA) is a common cause of nosocomial infection in the intensive care unit (ICU). A perception exists that ICU-acquired MRSA is associated with poor outcomes, although there are few data to support this.

AIM

To determine the effect of acquiring MRSA in the ICU on 180-day mortality, and to identify risk factors associated with acquisition.

METHODS

Data were collected prospectively from 2007 to 2013. Patients who remained MRSA negative throughout their ICU admission were matched with patients who acquired MRSA in terms of age, Acute Physiology and Chronic Health Evaluation II score, length of ICU stay and surgical/non-surgical status.

FINDINGS

In total, 2405 patients were included in the analysis. Patients who acquired MRSA in the ICU had significantly longer ICU stays than patients who were admitted with MRSA and patients who remained MRSA negative throughout their ICU stay (P < 0.001 for both). There were no significant differences in 180-day mortality between the groups (P = 0.238). A confirmed non-MRSA infection within 48 h of ICU admission was associated with increased risk of MRSA acquisition (adjusted odds ratio 2.57, P = 0.005), and receipt of antimicrobial therapy within 48 h of ICU admission was associated with reduced risk of MRSA acquisition (adjusted odds ratio 0.38, P = 0.014).

CONCLUSION

MRSA acquisition does not contribute towards mortality in critically ill patients. This raises questions regarding the cost-effectiveness of focusing infection prevention measures on the control of MRSA in ICUs. The low acquisition rate and lack of risk factors identified for MRSA in the study cohort indicate that efforts should be directed towards continual improvement of standard infection control procedures for all patients.

Continuous decontamination of an intensive care isolation room during patient occupancy using 405 nm light technology

Environmental contamination within intensive care units (ICU) is recognised as a source of patient infection, and improved cleaning and disinfection methods are continually being sought. Visible light of 405 nm has been shown to have bactericidal properties, and this communication reports on the use of a ceiling-mounted 405 nm light system for continuous environmental disinfection of contact surfaces and air in an occupied ICU isolation room. Levels of bacterial contamination on a range of contact surfaces around the room were assessed before, during and after use of the system. For each study, the lighting units were operated continuously during daylight hours. Results demonstrate that the spatial distribution of bacterial contamination was reduced almost uniformly across all sampled contact surfaces during use of the 405 nm light system. Pooled data showed that significant reductions in overall bacterial contamination around the room were achieved, with bacterial counts reduced by up to 67% ( p=0.0001) over and above that achieved with standard cleaning and infection control procedures alone. Use of 405 nm light significantly reduced environmental contamination across almost all sampled contact surfaces within the ICU isolation room. This has particular benefit in ICU where equipment and other ‘hand-touch’ sites make routine cleaning difficult, thus helping maintain a cleaner environment, and contributing to reducing cross-infection from environmental sources.

A survey of principal researchers who lead research into Adults with Incapacity in Scotland

BACKGROUND

Scotland's 'A' Research Ethics Committee (SAREC, previously MREC A) has exclusive authority to consider research involving Adults with Incapacity in Scotland. No appeal facility exists although resubmissions are accepted. Legislation covering research in England and Wales has created anomalies. RECs 'recognised' by the UK Ethics Committee (3 in Scotland, several in England) can approve drug studies involving Adults with Incapacity in Scotland. Several English RECs can approve studies led from outside Scotland.

METHODS

We conducted an anonymous online survey of researchers experienced in studies involving Adults with Incapacity to establish their opinions on the role of SAREC. The survey had 5 multiple-choice questions. Two questions invited a free-text comment.

RESULTS

Seventy-seven researchers (45% response) completed the survey. The majority (61/76, 80%) received a favourable opinion from SAREC immediately/after minor revision. The consensus was a single, experienced committee is advantageous to researchers (69/77 (90%)) and research participants (65/75 (87%)). There was no association between application outcome and opinion on whether a single committee is advantageous for researchers (p = 0.39 (Fisher's exact test)) or research participants (p = 0.49). Most (42/76, 55%) favoured the current system for reviewing decisions.

CONCLUSIONS

The research establishment favours retaining expertise in one committee. Most are content not having an external appeal facility.

Effect of socioeconomic deprivation and the appointment of Welfare Attorneys

Most patients in intensive care unit (ICU) lack decision-making ability. The Adults with Incapacity (Scotland) Act 2000 allows someone to appoint a Welfare Attorney (WA) to act on their behalf should they lose capacity. Scotland has areas of major socioeconomic deprivation associated with lower life-expectancy and with a lack of knowledge about and consequently difficulty accessing services. The effect of socioeconomic deprivation on WA registration was investigated. A complete list of registered WAs was categorized by deprivation. The Public Guardian, Scotland indicated whether patients admitted to ICU at Glasgow Royal (April 2006-May 2009) had a WA registered. All Scottish ICU admissions (2004-2008) were categorized by deprivation. Twelve of 1152 ICU patients at Glasgow Royal had a WA. Of 165,997 WAs registered, 5984 were in the most deprived and 27,970 in the most affluent areas. Overall, 3.9% of the Scottish population had a WA (1.4% in the most, 6.5% in the least deprived population decile). In conclusion, the uptake of WAs was low, especially in deprived areas. The reasons could include a lack of knowledge, not anticipating the need for a WA or not being confident in the process. Any educational package needs to target the most socioeconomically disadvantaged.

Public perception of emergency research: a questionnaire

BACKGROUND AND OBJECTIVE

Emergency research (e.g. into cardiac arrest or head injury) needs to start immediately, often before the patient, or relative, can give consent. A recent European Directive will prevent or severely limit emergency research. Little is known about the public view of emergency research.

METHODS

Patients attending the outpatient department of a university teaching hospital were invited to complete a self-administered questionnaire. Research Ethics Committee approval was obtained and participants gave written informed consent.

RESULTS

Three hundred and five of 362 respondents (84%) thought emergency research should start in the absence of consent but should be obtained as soon as possible from the nearest relative (82%) or the patient (90%). If consent was refused 62% felt the data could still be used, as did 81% if the patient died. Despite 62% approving of public meetings to publicize emergency research only 35% would attend one. A previously recommended list of preconditions was endorsed: no other consentable group (47%); advance consent impossible (55%); unable to delay treatment (73%); consent to be obtained as soon as possible (88%); an adequately designed protocol (74%); Ethics Committee approval (71%); patient may benefit (85%); future patients may benefit (92%) and that the treatment was necessary and could not be delayed (91%).

CONCLUSIONS

Emergency research must occur to improve the outcome from life-threatening illness or injury. The majority of people are aware of the importance of this research and that the normal rules of consent are not applicable. Alternative methods of recruitment need to be investigated.

Family witnessed resuscitation in UK emergency departments: a survey of practice

BACKGROUND AND OBJECTIVES

The American Heart Association guidelines from 2000 recommend that family members be allowed to witness cardiopulmonary resuscitation. This is controversial and opponents fear litigation and family interference during family witnessed resuscitation (FWR). The extent of FWR in UK Emergency Departments is unknown.

METHODS

A telephone survey of a selection of UK Emergency Departments was performed asking about experience with FWR.

RESULTS

One-hundred-and-sixty-two UK Emergency Departments with an average attendance of 47,000 patients per year participated. FWR was allowed by 128 (79%) for an adult patient and 93% for a child. Of these, 50% invited relatives to witness and only 21% did not permit FWR. The perceived benefits were: accepting that all possible has been done (48%), accepting the death (48%) and help with grieving (38%). Two percent did not think FWR was of help. Few had encountered any problems or interference from the family. Never being asked was the commonest reason not allowing FWR followed by staff reluctance. Most respondents would wish to be present if their child (85%), spouse/partner (64%) or elderly relative (52%) was being resuscitated.

CONCLUSIONS

FWR is common in UK Emergency Departments. It is more common when children are being resuscitated than adults. Further research is needed to demonstrate whether it is of benefit to the patient or relatives and its applicability to other areas such as intensive care.

The cardiovascular effects of inspired oxygen fraction in anaesthetized patients

BACKGROUND AND OBJECTIVE

Increased inspired oxygen fractions (FiO2) have significant haemodynamic effects in awake volunteers. We sought to establish whether these effects are also present in anaesthetized patients.

METHODS

We prospectively studied 30 ASA I-II patients, 15 in each of a propofol and sevoflurane group. Their haemodynamic responses, awake and anaesthetized, when the FiO2 was changed between 0.3 and 1.0 were measured with a non-invasive transthoracic bio-impedance monitor.

RESULTS

While preoxygenating awake patients in both groups the FiO2 was increased from 0.21 to 1.0. This reduced the mean cardiac index (3.38 +/- 0.5 to 3.03 +/- 0.5 L min(-1) m(-2); P < 0.001); reduced the heart rate (HR) (68.1 +/- 10.4 to 62.8 +/- 9.4 beats per minute (bpm); P < 0.001); and reduced the stroke index (50.4 +/- 9.6 to 48.5 +/- 8.6; P = 0.02). It increased the systemic vascular resistance index (2060 +/- 319 to 2220 +/- 382 dyn s(-1) cm(-5) m(-2); P = 0.002); but did not change mean arterial pressure. In the anaesthetized patients, when decreasing the FiO2 from 1.0 to 0.3, mean cardiac index (L min(-1) m(-2) increased (3.06 +/- 0.57 to 3.25 +/- 0.56, P = 0.008 for sevoflurane; 2.76 +/- 0.46 to 2.89 +/- 0.42, P = 0.002 for propofol). The mean HR (bpm) increased (65.1 +/- 7.8 to 69.1 +/- 7.5, P < 0.001 for sevoflurane; 67.5 +/- 11.8 to 72.7 +/- 11.6, P = 0.001 for propofol). The mean systemic vascular resistance (dyn s(-1) cm(-5) m(-2)) decreased (1883 +/- 329 to 1735 +/- 388, P = 0.008 for sevoflurane; 2015 +/- 369 to 1771 +/- 259, P = 0.003 for propofol). Mean arterial pressure (mmHg) decreased (74.8 +/- 8.7 to 71.4 +/- 8.7, P < 0.001 for sevoflurane; 72.1 +/- 8 to 66.5 +/- 6.8, P = 0.002 for propofol).

CONCLUSION

O2 has haemodynamic effects in awake and anaesthetized patients. These effects were of overall similar magnitude for patients anaesthetized with propofol and sevoflurane.

Relatives' knowledge of decision making in intensive care

BACKGROUND/AIM

The law on consent has changed in Scotland with the introduction of the Adults with Incapacity (Scotland) Act 2000. This Act introduces the concept of proxy consent in Scotland. Many patients in intensive care are unable to participate in the decision making process because of their illness and its treatment. It is normal practice to provide relatives with information on the patient's condition, treatment, and prognosis as a substitute for discussion directly with the patient. The relatives of intensive care patients appeared to believe that they already had the right to consent on behalf of an incapacitated adult. The authors' aim was to assess the level of knowledge among relatives of intensive care patients of both the old and new law using a structured questionnaire.

METHODS

The next of kin of 100 consecutive patients completed a structured questionnaire. Each participant had the questions read to them and their answers recorded. Patients were not involved in the study.

RESULTS

Few (10%) were aware of the changes. Most (88%) thought that they previously could give consent on behalf of an incapacitated adult. Only 13% have ever discussed the preferences for life sustaining treatment with the patient but 84% felt that they could accurately represent the patient's wishes.

CONCLUSIONS

There appeared to be a lack of public awareness of the impending changes. The effectiveness of the Act at improving the care of the mentally incapacitated adult will depend largely on how successful it is at encouraging communication and decision making in advance of incapacity occurring.

The effect of normobaric hyperoxia on cardiac index in healthy awake volunteers

Fifteen healthy volunteers were exposed to a stepwise increase in FIO2 between 0.21 and 1.0, and their haemodynamic responses were measured with a non-invasive transthoracic bio-impedance monitor. There was mean reduction in cardiac index from 3.44 to 3.08 l.min-1.m-2 (10.7%, p < 0.001). The mean reduction in heart rate was from 77.3 to 69.1 beats.min-1 (10.5%, p < 0.001) and the mean systemic vascular index increased from 2062 to 2221 dyne.s-1.cm-5.m-2 (7.7%, p < 0.025). There were no significant changes in stroke index or mean arterial pressure. These changes are similar quantitatively and qualitatively to those previously reported by dye dilution techniques.

Closing the audit loop--prevention of perioperative hypothermia: audit and reaudit of perioperative hypothermia

BACKGROUND AND OBJECTIVE

Perioperative hypothermia is generally regarded as undesirable, but its incidence rate in the elective procedures in our hospital and the effect of the preventative measures taken against it were unknown. An initial audit indicated that postoperative hypothermia occurred. Therefore, changes in practice were implemented to address the problem. A further audit was then undertaken to assess the impact of these measures.

METHODS

The first audit recorded data from 177 patients undergoing major elective surgical procedures. Variables recorded were: ASA classification, duration of operation, use and description of preventative measures for hypothermia, blood loss, intravenous fluids, and core and peripheral temperatures on arrival and discharge from the recovery room. The subsequent audit included 158 patients undergoing major general, orthopaedic or vascular surgical procedures. Patients had core temperatures measured preoperatively, immediately upon arrival in the recovery room, and just before discharge back to the ward. Core temperatures in both audits were measured using an infrared temperature probe.

RESULTS

The mean body temperature on arrival in the recovery room of patients in the initial audit was 35.5 degrees C (range 32.2-37.2, SD +/- 0.74), and in the subsequent audit 36.6 degrees C (33.6-38.2, +/- 0.72). These differences reached significance (P < 0.0001). This was despite an average duration of surgery of 133.5 (25-330) min in the initial study compared with 154.7 (90-480) min subsequently.

CONCLUSIONS

We found that with simple but consistently implemented changes in practice, postoperative hypothermia in elective patients could largely be eradicated.

Diversity and detection of nitrate assimilation genes in marine bacteria

A PCR approach was used to construct a database of nasA genes (called narB genes in cyanobacteria) and to detect the genetic potential for heterotrophic bacterial nitrate utilization in marine environments. A nasA-specific PCR primer set that could be used to selectively amplify the nasA gene from heterotrophic bacteria was designed. Using seawater DNA extracts obtained from microbial communities in the South Atlantic Bight, the Barents Sea, and the North Pacific Gyre, we PCR amplified and sequenced nasA genes. Our results indicate that several groups of heterotrophic bacterial nasA genes are common and widely distributed in oceanic environments.

In-flight medical emergencies: response of anaesthetists who were passengers on commercial flights

All consultants and trainees in anaesthesia in a large teaching hospital were surveyed. Details of the number of flights per year and details of any medical emergencies in which they had been involved were recorded. The mean number of flights per year was 7.1 domestic and 3.4 international. Of the 45 anaesthetists surveyed, 14 had dealt with emergencies in flight, four had dealt with more than one. The minor emergencies (12) included transient ischaemic attacks, abdominal pain and otitis media. The seven serious events included seizures, angina, hypoglycaemic coma, respiratory arrest and two fatal cardiac arrests. No flights were diverted. On only two occasions were their medical qualifications checked. Requests for documentation were unusual. On several occasions the equipment which was available was inadequate. All doctors that responded were insured in the UK and most stated that they would assist Americans on American airlines. Medical emergencies were more likely on long haul flights.

A comparison of the pharmacodynamics of rocuronium and vecuronium during halothane anaesthesia

Thirty healthy patients were randomised to receive either a single bolus dose of rocuronium 0.6 mg.kg-1 or vecuronium 0.1 mg.kg-1 during halothane anaesthesia. Onset time, duration 25, duration 75 and train-of-four 70 were measured. The onset of neuromuscular blockade following rocuronium was more rapid than vecuronium (p = 0.0001). All other pharmacodynamic parameters were similar. During the first minute following injection of the neuromuscular blocking agent, the heart rate increased by 36% in the rocuronium group but remained stable in those patients who received vecuronium (p = 0.0008). No adverse effects were noted in either group.