Page 134 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

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

urea nitrogen levels, and urine urea nitrogen levels. Indirect calorim- This randomized trial will help inform weaning protocols for CCI
37
etry, when available, can be used if overfeeding remains a concern. For patients. There are some data that support the use of weaning protocols
enteral formulas, a semielemental feed may be most appropriate for CCI in CCI patients over usual care by multiple clinicians. In one prospec-
patients with serum albumin concentrations of less than 2.5 g/dL to tive cohort study using historical controls, a respiratory therapist–
achieve better amino acid absorption and insulin response. implemented weaning protocol decreased median time to wean from
Enteral feeding through a nasogastric tube or a gastrostomy tube 29 days in historical control subjects to 17 days in the protocol group.
36
is the most common route of nutrition for the CCI patient. Enteral This protocol was applied in an LTAC hospital where the respiratory
feeding should be accompanied by careful attention to common compli- therapist-to-patient ratio was 1:7. A therapist-implemented protocol
cations. Persistent underfeeding can be prevented by using high limits such as this may be even more effective for CCI patients who are being
for gastric residuals or not following residuals at all. Sinus infections and managed in acute ICU settings where physician attention is often drawn
nasal complications can be reduced by using gastrostomy tubes placed to more severely ill patients. Success would be contingent on availability
with the help of interventional radiologists, endoscopists, or surgeons of experienced respiratory therapy staff.
assessments should be made of a patient’s swallowing capabilities to ■ AIRWAY MANAGEMENT
when enteral nutrition is expected to be prolonged (>30 days). Frequent
allow for as much oral feeding as possible. Oral feeding provides signifi- Although the benefits of early tracheostomy in the acute ICU setting
cant comfort to the patient and provides an important source of enjoy- remain a topic of debate, for the CCI patient who is not facing impend-
38
ment and empowerment. Oral feeding may have to be supplemented, ing death or extubation, tracheostomy is recommended. Tracheostomies
10
however, if it is limited by reduced stamina, nausea, dysphagia, or have many advantages, including improved comfort and communication,
depression. Parenteral nutrition is usually reserved for situations where less sedation requirement, lower dead space, and better pulmonary toilet,
enteral feeding is not possible owing to issues with enteral access or and they allow for oral feeding in some patients. They require lower lev-
function. However, when enteral nutrition is not proceeding smoothly, els of monitoring than endotracheal tubes, and facilitate transfer of the
prolonged periods of inadequate nutrition should be discouraged and patient to lower levels of care. Despite their advantages, they are not with-
supplementation with parenteral nutrition should be considered. 35 out acute and long-term complications. Acute obstruction by mucous
■ LIBERATION FROM MECHANICAL VENTILATION plugging or malfunction happens uncommonly, but consequences are
devastating. Therefore, caregivers should not become complacent with
Although PMV is one of the defining characteristics of CCI patients, regard to pulmonary toilet and monitoring, especially when patients are
until recently little data have existed regarding optimal approaches to weak and unable to signal for assistance. Despite such vigilance, mucous
liberation. Patients’ generally weakened states usually dictate a slower plugging may be unavoidable in some patients. Tracheal stenosis is an
pace of weaning than is recommended in the acutely critically ill uncommon occurrence but can be associated with signi ficant morbidity.
patient. However, patients can also have an unnecessarily prolonged An important question for CCI patients is timing of decannulation
course when clinicians and therapists are not aggressive enough. By after liberation from the ventilator. Clinicians often are tempted to
definition, most of these patients have failed early attempts at liberation. remove the tracheostomy tube quickly in order to simplify discharge
Subsequent efforts depend on continued maintenance of hemodynamic planning and improve patient comfort. This can be hazardous, however,
stability, avoidance of preventable complications, optimal nutrition, because patients remain diffusely weak after weaning and are at risk
frequent assessments of readiness for weaning, and careful exercise of for recurrence of respiratory failure for at least several weeks. They are
respiratory muscles to improve strength and function. also at great risk for aspiration. Swallowing function remains compro-
A standard approach to weaning usually involves work-rest cycles mised in many of these patients owing to muscle atrophy, pharyngeal
that include periods of “exercise” alternating with periods of “rest.” edema, neurologic dysfunction, and effects of the tracheostomy itself
What constitutes appropriate exercise and actual rest has been debated. on swallowing mechanics. Upper airway obstruction is also possible
Patients typically are maintained on mandatory ventilation with assist due to granulation tissue associated with the tracheostomy, vocal cord
control or synchronized intermittent mandatory ventilation during the dysfunction, and upper airway edema. Therefore, decannulation should
night. In the morning, the patient is placed on a setting requiring more take place in a stepwise fashion with careful assessments of swallowing
patient effort using some degree of pressure-support ventilation or function and airway patency. For patients who demonstrate adequate
trials of unassisted breathing using humidified oxygen via a tracheos- ability to protect their airway but remain at high risk of respiratory fail-
tomy collar. The degree of ventilatory support and length of exercise ure for other reasons, the tracheostomy tract can be kept patent after the
36
efforts depend on patient strength and endurance. Patients are moni- tracheostomy tube has been removed using a stoma stent. 39
or blood pressure, increased respiratory rate, anxiety or diaphoresis, or ■ PHYSICAL AND OCCUPATIONAL THERAPY
tored for early evidence of fatigue, as suggested by increased heart rate
oxygen desaturation. Frequent blood gas monitoring in slowly weaning Prolonged immobility can predispose patients to a range of organ dys-
CCI patients is not useful. functions, some of which are preventable. While CIP is difficult to
40
A randomized controlled trial of weaning approaches for CCI patients avert, disuse atrophy can be lessened in some patients, and joint contrac-
was completed at a long-term acute care (LTAC) hospital. Progressive tures can be avoided in most. Range-of-motion exercises should begin
37
pressure support weaning was compared with daily tracheostomy collar soon after intubation in the acute care ICU and continue throughout
trials: Successful weaning was more likely for patients randomized to the period of CCI. 41,42 While full-range-of-motion exercises involv-
the tracheostomy collar group and median weaning time was shorter ing multiple joints can tax a busy ICU nurse, nursing aides and even
(15 vs 19 days). Importantly, patients were screened prior to enrollment family members can contribute to the effort with instruction from phys-
by undergoing an unassisted breathing trial that lasted up to 5 days. The ical therapists. A mechanical ventilator should not prevent strength-
benefit for weaning time was significant in the subgroup of patients who ening exercises against resistance, sitting in bed with legs dangling,
failed the screening procedure between 12 and 120 hours. There was no transfers to a bedside chair, or even ambulation. These activities help
43
difference between groups for patients who failed the screening trial patients maintain balance and overcome orthostatic hypotension, which
within the first 12 hours. There was no difference in long-term survival can develop after only 4 to 7 days of bed rest. Recent studies have con-
44
between groups. Finally, the investigators also found that 32% of patients firmed the benefits of an early mobility protocol using a mobility team
who were screened passed their initial unassisted breathing trial, sug- in the acute ICU on decreasing ICU length of stay and helping prevent
gesting that a substantial number of patients who were determined to CCI. 41,42 Increased mobility interventions through the period of CCI
need prolonged weaning by physicians in referring hospitals had not are facilitated by the presence of a tracheostomy and the elimination of
been adequately assessed. sedatives when possible.

Section01.indd 100 1/22/2015 9:37:32 AM