224 Key Issues in Critical Care Nursing
Critical Care Nursing Knowledge and Skill Development
Patricia Benner is said to have revolutionized our understanding of clinical expertise in nursing. In her landmark book, From Novice to Expert: Excellence and Power in Clinical Nursing Practice, Benner related the Dreyfus Model of Skill Acquisition to her study of nursing expertise.1 This model was originally developed through a study of skill development among nonclinicians (e.g., chess players and airline pilots). Benner and her colleagues have recently directed their analysis specifically to critical care nursing.2
Some have argued that Benner’s conception of skill acquisition is also relevant to medicine.3 A recent study demonstrated that critical care physicians employ a similar mode of thinking in their practice of diagnostic reasoning.4
Concurrent with this management of a specific case, Benner and her associates further described how an expert nurse also monitors and limits potential hazards in the highly technological critical care environment, fosters teamwork, and initiates preventive and corrective management of systems breakdown.2 These functions are commonly performed without the nurse necessarily being consciously aware of the reasoning that underlies them.
Any strategy that diminishes or fragments the depth of critical care nursing expertise will fundamentally diminish the strength of a critical care service.5 Cho and associates have demonstrated that efforts to reduce nursing staffing levels can significantly increase levels of patient morbidity. A 1-hour decrease of worked nursing hours per patient was associated with a 8.9% increased probability of patients acquiring pneumonia.6
Clinical Topics
Pain and Discomfort
It is likely most nurses would list patient pain and discomfort as their most challenging clinical problems. The constancy and proximity of a nurse’s bedside relationship with a patient heightens awareness and attentiveness to unresolved pain and discomfort and can take a deep toll. This is partly due to nursing’s traditional commitment to the promotion of comfort and caring.7,8 Although significant advances have been made over the years in developing effective pharmacologic agents for managing these problems, pain and discomfort commonly persist.9,10
One factor that has limited successful management of these problems is the challenge involved in their evaluation.11 Outside the critical care setting, pain management has benefited from systematic measurement and documentation. Widely accepted pain measures such as the Visual Analogue Scale or numeric rating scales rely on patient self-report, but self-report is typically not accessible in critical care, given patients’ diminished level of consciousness. Thus, observational methods are most appropriate for this population. The Critical-Care Pain Observation Tool (CPOT) has demonstrated reliability and validity for critically ill adults regardless of their level of consciousness.12,13 The CPOT measures four behavioral categories: facial expression, body movements, muscle tension, and compliance with the ventilator for intubated patients or vocalization for extubated patients. Significant experience exists in pediatrics with the utilization of observational pain measures such as the FACES Pain Scale14 and the Children’s Hospital of Eastern Ontario Pain Scale, CHEOPS.15 However, most research has been conducted outside of critical care settings.
In critical care settings, overall “comfort” is increasingly measured with sedation scales.16,17 The Ramsay Scale, likely the most widely used sedation scale in the intensive care unit (ICU), has established some reliability and validity for critically ill adults.18 This is a six-level sedation scale, three levels for when the patient is awake and three levels for when the patient is asleep: 1—anxious, agitated, or restless; 2— cooperative, oriented, or tranquil; 3—responds to commands only; 4—asleep, brisk response to light touch on cheek or loud auditory stimulus; 5—sluggish response; and 6—no response. The American Association of Critical-Care Nurses has published a sedation assessment scale for critically ill patients that may be more sensitive to the end goals of sedation.19 It comprises five domains of assessment (consciousness, agitation, anxiety, sleep, patient-ventilator synchrony) as compared to many existing scales that focus only on one or two domains such as consciousness and agitation. In pediatric critical care, the COMFORT Scale has demonstrated impressive merits.20 This consists of eight behavioral and physiologic parameters including alertness, calmness/agitation, respiratory response, physical movement, blood pressure, heart rate, muscle tone, and facial tension. Each parameter is measured along a 5-point rating scale and summed to provide a total score that ranges from 8 to 40. Some work with this tool has indicated that physiologic parameters such as blood pressure and heart rate have weak validity as indicators of discomfort.21 Although these signs are commonly and intuitively associated with patient discomfort, they are also affected by numerous other phenomena within the critical care setting, such as cardiovascular dysfunction.
Delirium is the most common psychiatric diagnosis in critical care; its evaluation and management is therefore a key comfort concern for this population. The Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) is a valid and reliable tool developed for bedside assessment of delirium in aduts.22
Sedation in critical care is closely tied to the management of mechanical ventilation discomfort. A problem arising from this sedation-ventilation relation is the complex process of weaning patients from both therapies.23,24 Some research has examined the merits of daily interruption of sedation to permit spontaneous breathing.25,26 The use of a daily “sedation vacation” can help prevent some significant iatrogenic effects of critical care and shorten ICU and hospital stay.
Overall improvements in pharmacologic management of pain and discomfort have contributed to a more recent concern: withdrawal reactions.27 Overly rapid weaning of sedation and analgesia can precipitate a constellation of phenomena such as acute pain, excessive agitation, “ICU psychosis,” as well as withdrawal reactions. Reliable and valid measures for evaluating withdrawal reactions are therefore important in successfully managing this problem. Some strong measurement tools have been documented for the pediatric population.28,29
Although guidelines have been published for recommended rates of weaning, very little empirical research has established the optimal rate for reducing opioid and benzodiazepine infusions, balancing the need to rapidly extubate patients (and therefore minimize ventilation-related morbidities) with the prevention of withdrawal reactions. Some evidence suggests that one optimal weaning rate does not exist.30 It must be tailored to the length of time the patient has been receiving such infusions, whereby 20% daily weaning is optimal for patients receiving continuous infusions for 1 to 3 days, 13% to 20% for 4 to 7 days of infusions, 8% to 13% for 1 to 2 weeks, 8% for 2 to 3 weeks, and 2% to 4% for more than 4 weeks of infusions.30
In their study of critical care nursing judgment in the management of pain, Stannard et al. reported that nurses demonstrated a sophisticated balancing of patients’ analgesic needs against other competing needs.31 A less cumbersome pain and discomfort management process can be established through the use of a sedation protocol or standing orders that “transfer” some decisional autonomy to nurses. A protocol can authorize nurses to modify sedation and analgesia infusion rates and bolus administration according to a prescribed target level of patient comfort.
For example, Alexander and associates reported on a sedation protocol used in pediatric critical care where the COMFORT Scale was used to measure patients’ level of comfort.32 The physician’s prescription specifies a target COMFORT Scale range for the patient, which the nurse can then use as a guideline for modifying the administration of sedation and analgesia. This study reported that patient comfort was managed effectively while facilitating the decision-making process.
Finally, the nursing literature has devoted some attention to the use of nonpharmacologic means for managing pain and discomfort: massage, relaxation exercises, transcutaneous electrical nerve stimulation (TENS), acupuncture, guided imagery, and hypnosis, among others.33 However, these techniques have undergone very little clinical research investigation within critical care. In light of major adverse effects associated with pharmacologic agents, as well as their limitations in fully ensuring patient comfort, these adjunctive measures should be further developed for the critically ill.
Pressure Ulcers
In their study of iatrogenic problems, Cho and associates reported that pressure ulcers had the greatest impact on length of stay (i.e., a 1.84-fold increase).6 Documented prevalence rates vary from 7.1% to 11.1%.34 Jiricka et al. have reported that prevalence rates are even higher among the critically ill.35 This is attributable to the greater likelihood of immobility and reduced skin perfusion.
The principal extrinsic causes of pressure ulcers are pressure, friction, and shear. Therefore, preventive strategies are directed toward minimizing these extrinsic forces. Although over 200 pressure-relieving devices are commercially available, a paucity of controlled clinical trials have examined their efficacy.36
An emerging body of literature is effectively identifying the sites of pressure ulcers and the relative significance of various risk factors. This will help build a base of evidence from which clinical trials can be designed. This literature has led to the development of scoring systems for predicting the risk of pressure ulcers. A highly regarded system is the Braden Scale,37 which has six subscales: mobility, activity, friction and shear, sensory perception, skin moisture, and nutrition; it provides a total score that ranges from 6 to 23 points (high scores indicate less risk). A Braden score of 16 has demonstrated a high degree of sensitivity and specificity in predicting pressure ulcer formation in critically ill adults. This tool has recently been adapted and validated for the pediatric critical care population.38
Whereas pressure ulcers in adults predominantly appear on the lower body (sacrum, ischium, and heels), they are more common on the upper body of children (occiput and ears). This is a result of proportional differences in body weight distribution between these age -groups. A 27% rate of pressure ulcer incidence has been reported in critically ill children, 57% of which were identified on their second day in the ICU.39 Particularly disturbing was that an additional 27 ulcers were identified as caused by medical devices such as oximetry probes, BiPAP masks, and endotracheal tubes.
It is remarkable that wide disparities of preventive measures are currently practiced, including some high-cost pressure-relieving mattresses.36,40 These include some aids that are largely regarded as ineffective, such as synthetic sheepskins.39 Although a substantial amount of evidence has examined this problem outside of critical care, systematic evaluations of management strategies are required to understand their efficacy among the critically ill.