Page 43 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

12 PART 1: An Overview of the Approach to and Organization of Critical Care

QUALITY INDICATORS IN CRITICAL CARE staffing model the addition of a nighttime intensivist did not provide
■ STRUCTURE benefits; however, in low-intensity staffing ICUs, the presence of a night-

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time intensivist was associated with lower mortality. Clearly this field
Several structural characteristics of ICUs have been linked to better out- is a current and exciting topic, still open for discussion, with authors
comes. Although it is unlikely that there will be randomized controlled debating whether 24-hour intensivist staffing should 114,115 or not 116,117 be
trials comparing different models of ICU care, 44-57 nighttime availability adopted. Given the costs of staffing ICUs 24 hours a day, the unavail-
of intensivists, 7,58-68 staffing ratios, 69-86 volume of admissions, 87-94 special- ability of intensivists to staff ICUs even during daytime, and the lack
ized units, 95,96 shift models, availability of technology, 98-101 provider of evidence beyond reasonable doubt, it would be premature to suggest
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experience, teamwork, 103,104 or organizational climate, 105-108 the asso- that 24-hour intensivist staffing model should be universally adopted,
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ciation between some of these structural features and outcome is quite although it seems reasonable that some organizations may benefit from
strong. However, it must be kept in mind that organizational behavior is it, especially those with a low-intensity staffing model.
more complex than the individual structural factors and many organi- The most expensive part of intensive care is labor. There is a con-
zations may actually perform quite well in spite of not being compliant siderable body of literature trying to identify the ideal nursing staffing
with policy recommendations. ratios and a more limited set of studies looking at other clinician staff-
ICUs can use many different models of care, and the literature has ing. Not unexpectedly, an association between higher patient to nurse
confusing terminology for these different models. An ICU model usu- ratio and mortality has been demonstrated. Administrative data from
ally refers to intensivists’ degree of responsibility over patient care taken. general surgery, vascular and orthopedics patients in 168 hospitals in
In “closed” models, only intensivists have admitting privileges to the ICU Pennsylvania showed that there is an OR for mortality of 1.07 per each
and work in collaboration with the patient’s primary physician. “Open” extra patient per nurse. This represents five excess deaths per 1000
units allow the patient’s primary physician to retain full responsibility patients if the patient to nurse ratio goes from 4:1 to 8:1. Stemming
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over clinical decisions and consultation with an intensive care physi- from this important information from ward care, several authors have
cian is optional. The term high-intensity staffing model refers to either investigated this issue in more detail in the ICU. A meta-analysis of the
a closed ICU or an open ICU with mandatory intensivist consultation. current literature supports a decrease of 30% in nosocomial pneumonia,
A systematic review of the available evidence demonstrates 30% lower 50% in unplanned extubations, and 9% in mortality per increase in one
hospital and 40% lower ICU mortalities, as well as decreased length of registered nurse per patient per day. 69,83 Interestingly, there seemed to
stay, in high-intensity staffing model ICUs. High-intensity intensivist be a dose response effect, consistent with causality, when the data were
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staffing models are currently a major quality recommendation of several analyzed by quartiles of patients per nurse in the ICU: Models with 1.6
organizations. However, there are several issues to consider in this to 2 patients per nurse per shift were consistently better than models
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quality metric. First, with the exception of the United States, most large with 3 and even larger effects could be seen on the comparison with
ICUs are run under what would be considered a high-intensity model; models with 4. It seems reasonable to recommend models where nurses
therefore, the open ICU model is primarily an issue for one country. do not take responsibility over more than 2 critically ill patients per
Second, the available literature on this quality metric addresses how the shift. Obviously, organizations may choose a more fluid regimen, where
ICU is organized, not whether an individual patient has an intensivist nurses share responsibility over 4 patients, but one nurse may be dedi-
as their physician. At least one publication has demonstrated that, in a cated to a more acute patient when needed, while the other takes over 3
select group of critically ill patients, ICUs that have no access to inten- less intense patients.
sivists can have good outcomes. This study supports the complexities Unfortunately there are scarce data on the appropriateness of inten-
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of organizations and indicates the challenges of implementing system sivist staffing ratios. A single center study, where the expansions of the
changes on the basis of population studies; some ICUs may achieve ICU led to varying staffing rations over time (from 1:7.5 beds to 1:15
equally good outcomes with different models. Although it seems reason- beds), provides the only evidence available: There was no effect on mor-
able to suggest the closed ICU model as a policy, health care institutions tality with varying staff ratios, but length of stay seemed to be higher
could benefit from learning why these individual ICUs perform so well, in the model with 1 intensivist caring for 15 beds. There currently are
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in spite of not having a closed model. 110 no data to support recommendations regarding the most appropriate
Nighttime availability of intensivists is another area where the lit- intensivist staffing ratio.
erature uses confusing terms. It may refer to on-site 24 hours coverage Constant training is one of the hallmarks of highly reliable organiza-
by intensivists, to open ICUs where the evening is covered by intensiv- tions. Much of the training in health care organizations is performed
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ists, or to availability of consultants over the phone or via computer. on the job. Therefore, it is intuitive to consider the possibility that insti-
Interest in the subject was raised by reports of an association between tutions that have higher volumes of specific conditions should perform
weekend hospital admissions and mortality for several acute diagnoses, better. Higher volumes of specific conditions may also lead to better
such as abdominal aortic aneurysm, acute epiglottitis, and pulmonary outcomes by decreasing variability in diagnosis and focusing nursing
embolism. Several investigators pursued the question whether ICU expertise. In fact, there is a large amount of evidence linking hospital
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admissions at night or on the weekend were associated with mortality, volumes to better outcomes in several clinical conditions, including
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which led to heterogeneous results. 7,60-68 There is speculation that the AIDS, cardiology, 92,120 vascular surgery, cancer, orthopedics,
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heterogeneity of results may be due to different models of care: Units urology, neurosurgery, and critical care. 87,90 This is important for
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that have on-site intensivists may show no differences in mortality two reasons: (1) policy makers may choose to combine units to increase
between daytime and nighttime admissions, 60,61 while units without on- the volumes and (2) given the lack of adequate outcomes and process
site coverage may have worse outcomes for nighttime admissions. 7,65,67 quality indicators for benchmarking, health care consumers may choose
A meta-analysis, including data from 10 studies and more than 100,000 hospitals with higher volume as a surrogate of better outcomes.
patients, could not demonstrate a higher mortality due to nighttime Similar reasoning led to the concept of specialty ICUs in transplant,
admissions, even when stratified by subgroups according to intensiv- trauma, neurosurgery, and other areas. Some evidence points toward
ist coverage. The authors could demonstrate an association between better outcomes in units with lower diagnostic diversity 99,106 and in neu-
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weekend admissions and mortality, which may reflect the possibility rocritical care units for intracerebral hemorrhage. However, analyzing
that it is not only the availability of intensivists that makes a difference, data from almost 100,000 patients in 124 ICUs across the United States,
but that a more complex organizational behavior on weekends, which investigators could not demonstrate any benefit of specialty ICUs for
might include limited access to other hospital services, may be the most six medical conditions, including acute coronary syndrome, ischemic
important factor. More recent data, from administrative databases stroke, intracranial hemorrhage, pneumonia, abdominal and cardiotho-
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including 49 ICUs, demonstrated that in ICUs with a high-intensity racic surgery. In fact their data support the possibility that “boarding”
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