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Chapter 10

Critical Care

Damon Clark and Heidi Frankel

Key Points

1 Intensive care unit (ICU) utilization is expected to increase as “baby boomers” come of age.

2 Surgical patients benefit from receiving critical care delivered by multidisciplinary teams led by an

intensivist. Around the clock intensivist presence (24 × 7) may not affect mortality in ICUs with

high-intensity staffing, but is thought to be most useful in those with less-intense staffing models.

3 Delivery of evidence-based medicine in surgical ICU patients results in improved mortality and

morbidity. Streamlining comprehensively written guidelines into “bundles” and use of checklists may

improve compliance and outcome.

4 Scoring systems have been developed and refined to address population outcome (mortality) and to

quantify organ dysfunction in the ICU.

5 Oxygen delivery and extraction can be monitored using pulmonary artery catheters (PAC). There is

no benefit to supranormalization of values in ICU patients and likely of PAC monitoring in most

instances. Fluid resuscitation using functional dynamic monitoring may be more efficacious than that

targeted to static values. Focused echocardiography may provide advantages to interpretation of

cardiac function over more traditional methods to afford therapies that can improve outcome.

Patients in cardiac arrest or impending cardiac arrest should be managed with principles outlined in

current Advanced Cardiac Life Support Guidelines. One of the three rhythms that can produce

pulselessness can be treated electrically, the other two require pharmacologic therapy. Dysrhythmias

are treated by considering their duration and association with hemodynamic instability and heart

failure.

6 Hypoxemia may result from mismatch of ventilation and perfusion (V/Q), anatomic or physiologic

shunting, hypoventilation, or less so due to impaired diffusion. Carbon dioxide, a readily diffusible

gas, is addressed by altering alveolar ventilation. Acute lung injury (ALI) and adult respiratory

distress syndrome (ARDS) fall along a spectrum of pulmonary disease. Conventional ventilatory

strategies incorporate a low-stretch philosophy. Evidence-based rescue strategies include prone

positioning and early chemical paralysis for those with severe ARDS. Most other ventilated patients

should be lightly sedated, screened for delirium, and kept moving with daily assessment for the

ability to extubate. The role for airway pressure release ventilation, extracorporeal support, and

inhaled prostacyclins is evolving.

7 Venous thromboembolism (VTE) is a significant problem in surgical ICU patients and chemical

prophylaxis alone has been demonstrated to beneficially impact outcome. Low–molecular-weight

heparins are more efficacious than unfractionated heparin in those at the highest risk in this

population, if the risk of bleeding can be mitigated. New oral inhibitors of factors Xa and thrombin

(II) have not been trialed specifically for VTE prophylaxis in general surgery ICU patients, but these

agents will, undoubtedly, play a more important role in the future as more effective strategies to

reverse them are developed.

8 A conservative transfusion trigger (7 g/dL hemoglobin) may be appropriate in most surgical ICU

patients, including those with gastrointestinal bleeding, neurotrauma, cardiac disease, and sepsis.

9 ICU patients should undergo routine assessment and adequate support of their nutritional status to

preserve lean body mass, maintain immune function, and avert metabolic complications. Enteral

nutrition, delivered either gastrically or more distally, is invariably possible and preferred in most

states. Earlier evidence supporting administration of immunonutrition (including components such as

glutamine and omega-three fatty acids) has been refuted, although a hypocaloric, high-protein diet

may be beneficial in all. Patients who are not being enterally fed, particularly those who will require

mechanical ventilation for more than 48 hours or have a coagulopathy are candidates for

pharmacologic prophylaxis of stress gastrointestinal bleeding. Proton pump inhibitors may be

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superior to histamine-2 antagonists.

10 Acute kidney injury is a common complication in the surgical ICU and portends poor outcome. Few

preventative measures have been proven successful short of rapid attention to diagnosis and

treatment of sepsis and adequate volume resuscitation. Both continuous and intermittent dialysis

may be equally effective in treating patients and may be possible even in those with hemodynamic

instability.

11 To balance the risks of hyperglycemia and iatrogenic hypoglycemia, glucose control in ICU patients

should target levels between 140 and 180 mg/dL. Relative adrenal insufficiency is common in septic

ICU patients. Hypotension unresponsive to volume loading and pressors should prompt

consideration of glucocorticoid administration in this setting. Low levels of thyroid hormone may

not be indicative of hypothyroidism in ICU patients and should only be treated if accompanied by

clinical indications.

12 Successful resuscitation of sepsis requires rapid identification of acutely ill affected patients and

administration of broad-spectrum antibiotics. CVP-targeted resuscitation may be no more effective

than the use of clinical endpoints. Procalcitonin assays may be beneficial to appropriately shorten

the course of antibiotic therapy for bacterial infections without negatively impacting outcome.

Catheter-associated infections are often preventable; their prevention requires coordinated care and

various strategies, the most important of which is prompt catheter removal when no longer

required. Decontamination strategies aimed at reducing ventilator associated pneumonia and

methicillin-resistant Staphylococcus aureus infection may be efficacious.

Surgical patients requiring intensive care are unique in that they include those who have undergone

elective procedures as well as those who have been injured or require emergent or urgent operations.

As such, outcome, expectations and processes of care can be vastly different in surgical than in medical

ICU patients, the majority of whom are admitted emergently. It is, thus important, to consider whether

or not certain medical ICU literature is applicable to surgical patients. Most germane, mortality rates in

surgical ICUs are roughly 5% to 10%, as opposed to greater than 20% in most medical ICUs.1

1 Nonetheless, surgical ICUs and their patients share many features with those in medical ICUs.

Patients admitted to the critical care unit make up a large proportion of hospital cost and resources,

estimated to be roughly 1% of gross domestic product. More importantly, both surgical and medical

ICUs continue to find themselves understaffed. Both the supply of critical care practitioners is

inadequate and the demand is extensive, largely from aging patients with complex comorbidities

undergoing complicated procedures and multitrauma. There are approximately 3,000 boarded surgical

intensivists with less than 200 completing training annually, most of whom do not practice critical care

exclusively. In the United States, these surgical intensivists serve largely in surgical and surgical

specialty units of academic medical centers that account for approximately 10% to 15% of the nearly

6,500 ICUs with roughly 100,000 beds and 5 million admissions annually. The largest growing

demographic in hospitals overall and ICUs in particular, is the group over 65 years of age, now

accounting for over half of all admissions, resulting in ICUs practicing at over two-thirds of capacity.

ORGANIZATIONAL STRUCTURE OF CRITICAL CARE

The intensive care unit provides an environment that allows close monitoring and care by experienced

physicians, nurses, and other ancillary staff. Current ICUs have the following common features: (1) a

designated geographical space, (2) specialized monitoring and therapeutic capabilities, (3) resources to

provide continuous care, (4) appropriate nurse to patient ratio, and (5) specialized personnel. There is

controversy, particularly in surgical ICUs, as to how superspecialized they need be (visceral transplant

vs. cardiac surgery vs. noncardiac thoracic surgery). Practically, this is an issue of institutional volume

and expertise as there is little data to support superspecialization in surgical units (neurosurgical

patients, a notable exception). Diagnostic and therapeutic capabilities include invasive and minimally

invasive cardiac monitoring, basic and rescue modes of ventilation and adjuncts, extracorporeal support,

dialysis and hepatic support, and neurologic monitoring, as described below. ICU nurse to patient ratios

vary from 1:3 to 2:1 depending on patient acuity and therapeutic needs that may be addressed with a

scoring system such as the therapeutic intervention severity score (TISS).3 Finally, dedicated

pharmacists, dieticians, physical therapists, and advanced level practitioners such as acute care nurse

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practitioners have all been demonstrated to improve process compliance and patient outcomes.4–7

Traditionally there are two types of ICU organizational structures: open and closed formats. In an

open ICU, the patients are admitted under the supervision and care of the primary physician/surgeon.

The primary physician or surgeon is responsible for providing patient care including order entry and

communication with the family, with ultimate decision making power over clinical decisions. The

primary physician/surgeon also continues to care for patients in other areas of the hospital, providing

both continuity, but also deflecting focus from the moment to moment care of the most acutely ill and

injured in the ICU. In the open format, the primary physician has the opportunity for consultation of an

intensivist. Within a closed format ICU, the patient’s care is transferred to an intensivist whose only

responsibility is to take care of patients within the ICU. Of course, hybrid models exist regarding

division of labor with respect to order entry and family communication. A multidisciplinary team led by

an intensivist can function in either closed or open structures (utilizing the intensivist in the consultant

role in the open format); however, the ability to provide immediate and continuous care may be

compromised in fully open surgical ICUs. In fact, the benefit of a high-intensity staffing model (with an

intensivist-led team or mandatory intensivist consultation) is more apparent in surgical than in medical

ICUs (perhaps due to the difficulty of an operative surgeon to simultaneously manage an ICU patient),

with a 15% decrease in ICU mortality.8,9 There is other work that specifically points to the benefit of a

closed ICU structure in decreasing morbidity and mortality.10,11,12 Nonetheless, despite the care model

employed, exquisite communication between members of the primary surgical team, ICU team, patient

(if possible), and family is mandatory to ensure best outcome and satisfaction by all. In recognition of

this, in the United States, The Joint Commission for Accreditation of Hospital Organizations (TJC)

requires a handoff between members of the surgical and ICU teams when a patient is admitted to the

ICU from the operating suites.13

2 The natural progression of work on the success of a high-intensity ICU staffing model on outcome

would be to promote around the clock availability of such services.14 However, these 24/7 intensivist

models did not improve SICU mortality in several studies and reviews, although they reduced morbidity

and resource utilization in others.15–17 This may be a consequence of the fact that studies examining the

effect of around the clock care have largely been carried out at academic medical centers with robust

nighttime fellow coverage.18 A noctensivist can improve morbidity and mortality in ICUs with lowintensity staffing.

Finally, a taskforce rendered recommendations on the appropriate intensivist/patient ratio in teaching

institutions. A ratio of one intensivist to 14 patients should be maintained to ensure timely completion

of rounds, staff satisfaction, and provision of high quality patient care and education of trainees.19

Evidence-Based Care

Numerous extensively researched evidence-based guidelines have been developed covering many

aspects of critical care, including the management of sepsis, ventilator management, and administration

of nutrition among others, the most important of which will be discussed below.20

3 The most robust evidence lends itself to the multidisciplinary, multiprofessional development of

institutional protocols and clinical practice guidelines. Unfortunately, without electronic prompts or

other mechanisms in place, compliance by even well-intentioned practitioners may be less than ideal.

Thus, ICU care providers have developed memory aids in the form of checklists and bundles. Further,

this simplification of ICU processes, which, in turn, may improve outcome, lends itself to regulatory

scrutiny.

Checklists do not necessarily reinforce evidence-based care (although they certainly can). They are

meant to embody crew resource management strategies. The use of a daily goals checklist in the ICU

enables practitioners to ensure that important components of care are addressed. Vincent described the

acronym “FAST HUG” as a simple checklist mnemonic for ICU use (Table 10-1).21

In our ICU, we have added a component to each of the letters. Use of these checklists improves the

knowledge of the game plan by the entire care team. Pronovost and colleagues demonstrated that use of

a daily goals sheet improved understanding of the daily plan from 10% to 95% and effected a decreased

ICU length of stay.22

Table 10-1A FAST HUG

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