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Using Nursing Activities Score to Assess Nursing Workload on a Medium Care Unit

Armstrong, Elizabeth RN*; de Waard, Monique C. PhD*; de Grooth, Harm-Jan S. BSc, MD*; Heymans, Martijn W. PhD; Miranda, Dinis Reis MD, PhD; Girbes, Armand R. J. MD, PhD*; Spijkstra, Jan Jaap MD, PhD*

doi: 10.1213/ANE.0000000000000968
Critical Care, Trauma, and Resuscitation: Research Report

BACKGROUND: The medium care unit (MCU) or “stepdown” unit is an increasingly important, but understudied care environment. With an aging population and more patients with complex multiple diseases, many patients often require a higher level of inpatient care even when full intensive care is not indicated. However, the nurse-to-patient ratio required on a MCU is neither well defined nor clear whether this ratio should be adjusted per shift. The Nursing Activities Score (NAS) is an effective instrument for measuring nursing workload in the intensive care unit (ICU) but has not been used in an MCU. The aim of this study was to measure the nursing workload per 8-hour shift on an MCU using the NAS and compare it with the NAS from an ICU in the same hospital. We also compared the NAS between groups of patients with different admission sources.

METHODS: The NAS was prospectively measured per patient per shift for 2 months in a 9-bed tertiary referral university hospital MCU and during a similar period in an ICU in the same hospital.

RESULTS: The mean NAS per patient did not differ between day (7:30 AM to 4:00 PM) and evening (3:00 PM to 11:30 PM) shifts, but the NAS was significantly lower during the night shift (11:00 PM to 8:00 AM) than during the day (P < 0.0001) and evening (P < 0.0001) shifts. The mean NASs in the ICU for day and night shifts were significantly lower than the scores in the MCU (P = 0.0056 and P < 0.0001, respectively), but NAS during the evening shift did not differ between the ICU and the MCU. The mean NAS for patients admitted to the MCU from the accident and emergency department was significantly higher than for those admitted from the ICU (P = 0.002), recovery (P = 0.002), and general ward (P < 0.0001). Patients on the MCU had a NAS comparable with that of ICU patients.

CONCLUSIONS: In our university hospital, NAS was higher during the day and evening hours and lower at night. We also found that patients from accident and emergency had a higher NAS than those admitted to the MCU from other locations. NAS in the MCU was not lower than the NAS in the ICU. Because of its ability to discriminate between day and evening workloads and between patients from different sources, the NAS may assist MCU managers in assessing staffing needs.

From the *Department of Intensive Care, VU University Medical Centre, Amsterdam, The Netherlands; Department of Epidemiology and Biostatistics, VU University Medical Centre, Amsterdam, The Netherlands; and Department of Intensive Care, University Hospital Groningen, Groningen, The Netherlands.

Accepted for publication July 23, 2015.

Funding: None.

The authors declare no conflicts of interest.

Reprints will not be available from the authors.

Address correspondence to Jan Jaap Spijkstra, MD, PhD, Department of Intensive Care, VU University Medical Center, Postbus 7057, 1007 MB Amsterdam, The Netherlands. Address e-mail to

In most European countries, a growing need for optimal use of resources and a relative shortage of intensive care unit (ICU) beds has increased the need to use ICU beds only for patients who fulfill the criteria for intensive care. However, many patients are too sick to be cared for in a normal nursing ward but do not meet ICU criteria, for example, because they require only monitoring instead of intensive treatment.1 To accommodate these patients, a new kind of unit has been developed called the medium care unit (MCU; also referred to as intermediate care or high-dependency units).2 These units admit patients not only from the recovery room and ICU but also from the emergency room and general wards. In the Netherlands, MCU is a specialty for registered nurses and requires a 1-year training period in addition to their regular nursing training. Because of the large gap between the care provided on the ICU and the general ward,3 the MCU is a means of adjusting patients to decreasing care levels and lower nurse-to-patient (N/P) ratios. Although presumably lower than that in the ICU, the level of N/P ratio required on an MCU remains unclear, with reported figures ranging from 1:4 to 2:3.4,5

Identifying an appropriate care ratio for the MCU is important, because a ratio too high will increase costs and a ratio too low may increase complications and even mortality.6,7 In our MCU, the patient population has gradually shifted from patients requiring postoperative care to those admitted from the ICU for stepdown care and patients primarily admitted to the MCU. To better understand nursing workload in the MCU, we used the Nursing Activities Score (NAS) to determine the time nurses actually spend on patient care.8

The NAS was originally developed for ICU use to measure the workload per patient for a 24- hour period. Because we felt that the workload in our MCU was not evenly distributed over 24 hours, we applied the NAS per 8-hour shift.

We evaluated the use of NAS to assess nursing workload on an MCU and explored whether the workload varied between different shifts and depended on the admission source of the patients. Furthermore, we compared the workload of patients in the MCU with patients in the ICU and assessed the interrater reliability of NAS on the MCU.

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Study Setting

This prospective cohort study was performed over a 2-month period in our MCU. The MCU in the Vrije Universiteit University Medical Centre (Amsterdam, The Netherlands) is an integrated component of the ICU department and consists of 9 designated beds. Patients are admitted to the MCU from accident and emergency (A&E), general wards (both medical and surgical), the recovery room, and the ICU. The nursing staff consists of registered MCU nurses and nurses studying for MCU or intensive care diplomas. There are no nursing assistants employed on the unit. Every weekday (but not during the weekend), a secretary attends to paperwork from 8:00 AM to 5:00 PM. Paperwork related to transferrals and admissions outside of these hours is done by the nurses. During the day shift (7 days a week), 1 or 2 cleaning personnel assist nurses by performing odd jobs in addition to cleaning, if time is available.

During the study, the usual N/P ratio was 1:2 during the day shift (5 nurses for 9 beds), a mixture of 1:2 and 1:3 (4 nurses for 9 beds) during the evening shift, depending on the availability of nurses, and 1:3 for the night shift (3 nurses for 9 beds). The day shift begins at 7:30 AM and lasts until 4:00 PM; the evening shift runs from 3:00 PM until 11:30 PM; and the night shift is from 11:00 PM until 8:00 AM. Other than the number of nurses employed per shift, nursing competency, seniority, and experience did not differ between shifts.

For comparison, the NAS was also measured during a 3-month period in the ICU during similar day, evening, and night shifts. Shift change times in ICU and MCU were the same.

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MCU Admission Criteria

Patients are admitted to the MCU requiring treatment or monitoring that cannot be given on the ward or who require a sufficiently intense level of care that the nursing workload would be considered too high for the ward. Patients generally have monoorgan failure, including noninvasive ventilation, but excluding the need for tracheal intubation. On occasion, patients are treated for multiple organ failure with limited need for organ replacement therapies. Allowable therapies for MCU patients include the use of vasoactive and inotropic medication, noninvasive ventilation, and continuous infusions of fentanyl, midazolam, or propofol for sedation. Allowable monitoring strategies for MCU care include invasive hemodynamic monitoring (excluding Swan-Ganz catheterization), intracranial pressure monitoring, and extended electroencephalographic monitoring. The decision to admit or to dismiss a patient from the MCU is always made by the attending intensivist in consultation with the registered nurse staff. This decision is usually based on the clinical needs of the patients but may rarely be influenced by ICU bed availability or occupancy.

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Study Variables

The NAS consists of a 23-item checklist (Appendix 1) describing basic nursing activities routinely performed in a 24-hour period. Each item is allocated a numeric score or weight, the summation of which gives the NAS for a 24-hour period. The numeric score was developed in such way that it represents the percentage of working time actually spent doing these specific tasks. A NAS of 50 for a patient would indicate that 50% of the working time of the nurse was spend caring for this patient. In other words, caring for this patient would require 0.50 full-time equivalent ICU nurses. The 23 items produce a possible score of between 0 and 177, where 177 equates to 1.77 full-time equivalent ICU nurses.8 All items on the NAS checklist were compatible with nursing activities performed on our MCU unit except for item 14: left atrium monitoring with a pulmonary artery catheter with or without cardiac output measurement. For the purpose of our study, which assessed NAS for 8-hour shifts (instead of 24 hours), some minor adjustments were also made in the original text of the NAS. The weighting of the individual items was otherwise unaltered. Before beginning the study, all 31 participating nurses received instruction in the content and during registration of NAS, but they were blinded to the weighting of the individual items. At the end of each 8-hour shift, nurses retrospectively completed the NAS checklist for their patient(s). Patients were only eligible for the study if they were admitted to the MCU for ≥4 hours within 1 shift.

NASs were then entered into a database, and the average scores, per patient, per shift were calculated. Other information entered into the database included age, gender, referring specialty, source of admission, length of stay (LOS) in the MCU, and Acute Physiology and Chronic Health Evaluation (APACHE) II score on admission. In addition, all participating nurses were allocated ID codes, which were also entered into the database. These were used to identify any individual who was not completing the checklist correctly, enabling those conducting the study to offer support and guidance at an early stage and to assess the interrater reliability of NAS on the MCU in this study.

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Statistical Analysis

Calculations were performed using SPSS 20 (IBM Corporation, New York, NY). Continuous variables are reported as mean ± SD, and noncontinuous variables (Shapiro-Wilk test) are reported as median (interquartile range). Categorical variables are reported as numbers and percentages. To test for significant differences, Student t test or Mann-Whitney U test was used as appropriate.

Relationships among the variables age, sex, source of admission, LOS, and the NAS were evaluated. The linear mixed models accounted for the repeated assessments within patients. These repeated assessments were defined as the level I and patients as the level 2 variable information. The model was further specified using a random intercept to account for the correlations within patients. An unstructured correlation structure was chosen because, for this structure, the model fit was best. Different transformations of the LOS variable were tested in relationship with the outcome variable NAS to confirm that we fulfilled the linearity assumption. We tested not only the quadratic and cubic transformations but also the proposed transformations of 1/LOS and 1/LOS2. Neither of these transformed variables was significant. Furthermore, the −2 log-likelihood values of these models did not decrease significantly from the model that did not include these transformations.

The between-nurse and between-patient variance components are reported as a marker for the interrater reliability of the NAS. The between-nurse SD represents sample variance in mean NAS (for each nurse) between the 26 nurses in the database. Similarly, the between-patient SD represents the sample variance in mean NAS between patients. The residual SD represents the random variance in the sample after patient-mean, nurse-mean, and shift-mean effects are considered. Bootstrapped Bonferroni adjusted 95% confidence intervals (5000 repetitions) were added to the point estimates of the variance components. All model residuals were checked for normality. These analyses were performed using SAS 9.2 (SAS Institute Inc., Cary, NC) and Stata 12 (StataCorp LP, College Station, TX). A 2-sided P ≤ 0.05 was considered to indicate statistical significance.

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Ethical Committee

Medical Ethics Review Committee of VU University Medical Center approved the anonymous use of the patient data for this study and is registered with the US Office for Human Research Protection as IRB00002991.

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Over a 2-month period, 87 patients were scored at the end of each nursing shift. Not all patients were scored on all 3 shifts, as some were admitted for <4 hours in 1 shift. Of a possible total number of 748 scores, 739 were actually completed. Of the 739 completed checklists, 5 were discarded from the study because of missing or incomplete information (2 from the day shift, 2 from the evening shift, and 1 from the night shift). The total number of completed scores was 271 of 277 for the day shift, and 216 of 222 for the evening shift, and 247 of 249 for the night shift.

The patients had a mean age of 58 ± 17 years and a mean APACHE II score of 11 ± 5, and 52% were men (Table 1). Five patients were admitted to the MCU from the general wards (6%), 16 from A&E (18%), 35 from the recovery room (40%), and 31 from the ICU (36%). The median LOS was not different among patients coming from the wards, A&E, recovery room, or ICU. The most common referral specialties were surgical (43%), neurosurgical (37%), and medical (21%). Eleven of the patients (13%) died during their hospital stay, and 3 died during their stay on the MCU.

Table 1

Table 1

The mean NAS during the night shift was lower than that measured during the day and evening shifts (both P < 0.0001; Table 2). NAS between day and evening shifts did not differ. NASs on weekdays and on weekends did not differ (data not shown; P = 0.448). Patient gender, age, or LOS on the ICU had no effect on the NAS or nursing workload at the MCU.

Table 2

Table 2

For comparison, the NAS was then measured during 3 months on the ICU. In the ICU, the mean NAS was 41.8 ± 11.0 (n = 1365) during day shift, 43.1 ± 10.0 (n = 1207) during the evening shift, and 32.7 ± 9.8 (n = 1261) during the night shift. The NAS during day and night shifts were both significantly higher than the NAS during the night shift (P < 0.0001; Table 2). The NAS in the ICU for day and night shifts were significantly lower than the scores in the MCU (P = 0.0056 and P < 0.0001, respectively).

Table 3

Table 3

Patients admitted to the MCU from the A&E had a higher NAS than those admitted from the ICU, recovery room, or general ward (Table 3). Neither NASs of patients referred from the ICU and those coming from the ward or recovery room nor did NASs for patients referred from the ward and those from the recovery room differ.

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In this study, we used the NAS to measure nursing workload on an MCU and observed that NAS was higher during the day and evening shifts than during the night shift. NAS was also higher in patients admitted from A&E department than from other departments but did not differ among patients from the ICU, the ward, or the recovery. We also compared NASs between ICU and MCU patients and found no relevant differences.

We encountered little difficulty in implementing the NAS in the MCU. During the first week of the study, nurses raised frequent questions on the interpretation of certain checklist items. However, the checklist was quite rapidly incorporated into the nurses’ daily routine. By using the patient data management system, it was possible to verify the accuracy of information being recorded. Early in the process, it became clear that 2 items were being inaccurately scored. Items 9 (oxygen therapy) and 21 (enteral feeding) were frequently not scored, even though the patients were actually receiving those therapies. When the participating nurses were made aware of the situation, the accuracy of the scoring improved and, if necessary, the omissions were retrospectively corrected using patient data management system. We measured a relatively low between-nurse SD, which is indicative of the good interrater reliability of the NAS.

The workload per patient in our MCU proved to be high, with equal scores in day and evening shifts, equivalent to N/P ratio of 1:2, and a slightly lower score in night shifts, equivalent to a ratio of 1:3. The N/P ratio on an ICU is normally 1:1 to 2, whereas the ratio on a general ward is approximately 1:10.9 These data are consistent with a survey on MCU organization in the Netherlands,10 which found a mean ratio of 1:3 for MCUs. Earlier attempts to measure nursing workload on MCUs with intermediate Therapeutic Intervention Scoring System (TISS) also found N/P ratios ranging from 1:2 up to 1:4.4 A study measuring the workload on a high-dependency unit in the United Kingdom using the TISS 28, together with a locally developed Nurse Dependency Score, reported a required ratio of 2:3.5 The differences in reported workload may reflect heterogeneity in the population studied or, alternatively, that earlier studies underestimated the actual workload because of the emphasis of TISS on technical tasks. It is also possible that the patient mix on the MCU may differ according to local habits and training level of the MCU nurses and availability of ICU and MCU beds. This variability is supported by the American Society of Critical Care Medicine, which recommends that the N/P ratio in MCU facilities be adjusted for local factors.11 The workload found in our MCU was comparable with the results recently published regarding a Belgian ICU,12 and mean NAS values over the first 3 months of 2014 in our ICU were also comparable with those on the MCU. These scores were similar, despite the relatively low APACHE II score of our patients on MCU admission (11 ± 5, compared with 23 ± 9 on our ICU). That mean NASs in the MCU was comparable with those in our ICU, and those in ICU in the aforementioned study can also be explained by the fact that NAS reflects the nurse’s jobs in all aspects not just those related to medical interventions.

To date, the most widely used instruments to measure nursing workload have been TISS13–15 and Nine Equivalents of Nursing Manpower use Score (NEMS),16 which measure technical interventions performed on ICU patients as a proxy for the amount of nursing care required. In an IC environment, the number of interventions and the nursing care required should increase with the seriousness of the patients’ underlying condition. In the development of the NAS, however, items were selected with attention to time spent on specific nursing tasks. The list of activities was then converted into the items to include in the score. Whenever possible items referred to work activities required to the performance of tasks instead of tasks defined by diagnoses or interventions. For example, washing, cleaning, and lifting were included in the NAS instead of Swan-Ganz, gastric bleeding, etc. This methodology resulted in 2 important features of the NAS: (1) the NAS describes nearly all nursing activities in the unit. During the multicentre field research (in 105 general ICUs), only 1.9% of nursing activities could not be measured by an NAS item, and 81% of all ICU nursing activities were represented versus only 43% in TISS-like scoring systems.8 (2) Because the NAS focuses on work activities, it may be applicable to nursing activities in other care environments and is insensitive to the introduction of new ICU technologies. Interest in the NAS is rapidly increasing,12,17–24 and the use of NAS in specific ICUs is increasingly being reported.22,25,26 Although it is possible that the frequency of the different items scored in NAS differs between the ICU and MCU, we did not study that possibility. Our results are compatible with another study that found that nurses spend more time caring for patients who were categorized as high dependency than those categorized as needing intensive care.27

Because admission and discharge of most patients and many routine procedures and investigations occur during the day shift, we were initially surprised that the workload in the evening shift was as high as that in the day shift. On reflection, however, we noted that the evening shift receives a substantial number of the admissions, e.g., postoperative patients from the recovery room. In fact, only about half of the admissions occur between 8:00 AM and 5:00 PM. In addition, during the day shift, support staff is available to assist in administrative work, whereas such staff are mostly lacking in the evening shift. Mobilizing patients and busy visiting hours also increase the mean workload in the evening. Finally, during the day shift (7 days a week), 1 or 2 cleaning personnel may often assist the nurses by performing odd jobs if time is available. This high workload in the evening shift was recognized by most nurses, who reported an excessively heavy nursing workload that occasionally compromised the delivery of high-quality nursing care. Our results were consistent with our ICU and others,15 which also found an equivalent workload between evening and day shifts.

We also found that the NAS was higher in patients referred from A&E sources than from other areas and that post-ICU patients were not more labor intensive, regardless of their ICU LOS. This finding was unexpected, because the MCU functions as a stepdown unit for patients from the ICU who are often still in need of intensive treatment: (endobronchial suctioning, intermittent continuous positive airway pressure [CPAP], vasoactive medication, intensive monitoring, or nursing care). Transferring these patients to the MCU, instead of waiting until they are well enough for the ward, releases ICU beds for patients in need of more aggressive treatment. Hence, we expected this patient category to have a higher NAS. In addition, in our hospital, the percentage of admission days for these MCU patients admitted from the ICU has increased, and at the same time nursing perceptions of patient workload in the MCU have increased. In contrast, patients with the highest workload (those admitted from A&E) accounted for only a minority of the total number of admission days. One possible reason for an increased perceived workload without a change in NAS could be that advanced training of MCU nurses has allowed sicker patients who previously required ICU care to be cared for in the MCU. The high workload observed in our study underscores the importance of measuring nursing workload, especially in stepdown units like this one. These units, which are usually less well staffed than ICU, must deal with a steady increase in the complexity of medical procedures in increasingly elderly patients.

Our study has several limitations. First, our study sample may be too small to definitively identify differences in nursing workload between groups. The number of patients originating from the wards may, in particular, be too small to compare with other groups. Second, our study is a single-centre study, performed on the MCU of a referral hospital. Because of increasing demand for ICU beds, our hospital puts considerable effort into educating and training our nursing staff to care for our MCU patients. Although the decision to admit or transfer a patient to our MCU is based on the clinical needs of the patient, it is possible that other hospitals with less demand for ICU beds may have different patients in their MCUs, in which case the NAS measured in our hospital may not be generalizable to those of other locations. Third, the NAS was originally developed to be used per 24 hours, and all the items were weighed accordingly. Using the same weights for 8-hour shifts needs validation in larger multicentre studies.

In conclusion, we found that measuring the nursing workload, per patient, per shift, on the MCU with NAS produced results consistent with previous data and with patterns of care in our hospital. The participating nurses found that the checklist was clear and required on average no more than a few of minutes to complete. This assessment was done in a relatively short period of 2 months, and more research is necessary. However, our study suggest that the use of the NAS to measure and discriminate workloads may assist medical and nursing staff in determining the number of patients who can be cared for by a given number of available nurses or for optimally adjusting the N/P ratio. The NAS may also be useful in adjusting the patient mix on the MCU to avoid an excessively high workload for nursing staff.

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Nursing Activities Score Items and Weights

  1. Monitoring and titration
    • a. Hourly vital signs regular registration and calculation of fluid balance.
    • b. Present at bedside and continuous observation or active for ≥2 hours in any shift for reasons of safety, severity, or therapy, such as noninvasive mechanical ventilation, weaning procedures, restlessness, mental disorientation, prone position donation procedures, preparation of administration of fluids, and/or medication.
    • c. Present at bedside and continuous observation or active for ≥4 hours in any shift for reasons of safety, severity, or therapy such as those examples listed earlier.
  2. Extra laboratory measurements, biochemical investigations, and microbiologic investigations.
  3. Medication: Vasoactive drugs excluded.
  4. Hygiene procedures
    • a. Performing hygiene procedures such as dressing of wounds and intravascular catheters, changing linen washing patient incontinence, vomiting, burns, leaking wounds, complex surgical dressing with irrigation, special procedures (e.g., barrier nursing, cross-inflection related, room cleaning after infections, staff hygiene), etc.
    • b. The performance of hygiene procedures took >2 hours in any shift.
    • c. The performance of hygiene procedures took >4 hours in any shift.
  5. Care of all drains except gastric tube.
  6. Mobilization and positioning, including procedures such as turning the patient; mobilization of the patient, moving from bed to chair; team lifting (e.g., immobile patient, traction, prone position).
    • a. *Performing procedure 1 time per 8 hours.
    • b. *Performing procedure more frequently than 1 time per 8 hours or with 2 nurses.
    • c. Performing procedure with ≥3 nurses (and frequently).
  7. Support and care of relatives and patient including procedures such as telephone calls, interviews, and counseling. Often, the support and care of either relatives of patient allow staff to continue with other nursing activities (e.g., communication with patients during hygiene procedures, communication with relatives while present at bedside and observing patient).
    • a. Support and care of relatives and patient requiring full dedication for about 1 hour in any shift such as to explain clinical condition, dealing with patient and distress, difficulty, and family circumstances.
    • b. Support and care of relatives and patient requiring full dedication for 3 hours or longer in any shift such as to explain clinical condition, dealing with patient and distress, difficulty, and family circumstances.
  8. Administrative and managerial tasks
    • a. Performing routine tasks such as processing of clinical data, ordering examinations, professional exchange of information (e.g., ward rounds).
    • b. Performing administrative and managerial tasks requiring full dedication for about 2 hours in any shift such as research activities, protocols in use, admission, and discharge procedures.
    • c. Performing administrative and managerial tasks requiring full dedication for about ≥4 hours of the time in any shift such as death and organ donation procedures, coordination with other disciplines.
  9. Respiratory support: Any form of mechanical ventilation/assisted ventilation with or without positive end-expiratory pressure, with or without muscle relaxants; spontaneous breathing with positive end-expiration pressure (e.g., CPAP or biphasic positive airway pressure [biPAP]), with or without endotracheal tube; supplementary oxygen by any method.
  10. Care of artificial airways: endotracheal tube or tracheostomy cannula.
  11. Treatment for improving lung function: thorax psychotherapy, incentive spirometry, inhalation therapy, intratracheal suctioning.
  12. Vasoactive medication, disregard type, and dose.
  13. Intravenous replacement of large fluid losses. Fluid administration >3 L/m2/d, irrespective of type of fluid administrated.
  14. Left atrium monitoring. Pulmonary artery catheter with or without cardiac output measurement.
  15. *Cardiopulmonary resuscitation after arrest; in the past period of 8 hours (single precordial thump not included).
  16. Hemofiltration techniques. Dialysis techniques.
  17. Quantitative urine output measurement (e.g., by indwelling urinary catheter).
  18. Measurement of intracranial pressure.
  19. Treatment of complicated metabolic acidosis/alkalosis.
  20. Intravenous hyperalimentation.
  21. Enteral feeding: through gastric tube or other gastrointestinal route (e.g., jejunostomy).
  22. *Specific intervention(s) in the intensive care unit. Endotracheal intubation, insertion of pacemaker, cardioversion, endoscopies, emergency surgery in the past period of 8 hours, gastric lavage. Routine interventions without direct consequences to the clinical condition of the patient, such as X-rays, echography, electrocardiogram, dressing, or insertion of venous or arterial catheters, are not included.
  23. Specific interventions outside the intensive care unit. Surgery or diagnostic procedures.

In the items 1, 4, and 6 to 8 only 1 subitem (a, b, or c) can be scored. The weights represent the percentage of time spent by 1 nurse on the activity mentioned in the item, if performed. Items marked with an asterisk were modified to fit in an 8-hour shift period instead of a 24-hour period.

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Name: Elizabeth Armstrong, RN.

Contribution: This author helped design the study, conduct the study, collect the data, and analyze the data.

Attestation: Elizabeth Armstrong attests to the integrity of the original data and the analysis reported in this manuscript and approved the final manuscript.

Name: Monique C. de Waard, PhD.

Contribution: This author helped design the study, conduct the study, collect the data, analyze the data, and prepare the manuscript.

Attestation: Monique C. de Waard attests to the integrity of the original data and the analysis reported in this manuscript and approved the final manuscript.

Name: Harm-Jan S. de Grooth, BSc, MD.

Contribution: This author helped collect the data, analyze the data, and prepare the manuscript.

Attestation: Harm-Jan S. de Grooth attests to the integrity of the original data and the analysis reported in this manuscript and approved the final manuscript.

Name: Martijn W. Heymans, PhD.

Contribution: This author helped collect the data, analyze the data, and prepare the manuscript.

Attestation: Martijn W. Heymans attests to the integrity of the original data and the analysis reported in this manuscript and approved the final manuscript.

Name: Dinis Reis Miranda, MD, PhD.

Contribution: This author helped analyze the data and prepare the manuscript.

Attestation: Dinis Reis Miranda attests to the integrity of the analysis reported in this manuscript and approved the final manuscript.

Name: Armand R. J. Girbes, MD, PhD.

Contribution: This author helped analyze the data and prepare the manuscript.

Attestation: Armand R. J. Girbes attests to the integrity of the analysis reported in this manuscript and approved the final manuscript.

Name: Jan Jaap Spijkstra, MD, PhD.

Contribution: This author helped design the study, conduct the study, collect the data, analyze the data, and prepare the manuscript.

Attestation: Jan Jaap Spijkstra attests to the integrity of the original data and the analysis reported in this manuscript and approved the final manuscript, and is also the archival author.

This manuscript was handled by: Avery Tung, MD.

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