Daily Assessment of the Critically Ill Patient

Chapter 201 Daily Assessment of the Critically ill Patient



Linda Barton, DVM, DACVECC



KEY POINTS



• Optimal care of the critically ill patient is provided for when information collected by physical examination and clinical observation is integrated with the results of ancillary tests and technologically derived data.

• The ideal monitoring plan allows for early detection of metabolic or physiologic derangements yet minimizes the risks for iatrogenesis, unnecessary expense to the client, and inappropriate use of intensive care unit resources.

• Use of a checklist of parameters to be evaluated will enhance both efficacy and efficiency of the critically ill patient’s daily assessment.


INTRODUCTION


Daily assessment of the critical patient begins with a thoughtful, history-guided physical examination. In the increasingly technical environment of the intensive care unit (ICU), the hands-on clinical assessment of a patient may be deemed less important than numbers recorded on a flow sheet. It is important that laboratory data and monitored parameters do not eclipse the value of the clinical evaluation of the patient. Optimal care is provided when information collected by physical examination and clinical observation is integrated with the results of ancillary tests and technologically derived data. The combination of subjective and objective information should be used to develop the daily diagnostic, therapeutic, and monitoring plan for the critically ill patient.


The type and frequency of monitoring should be based on the underlying disease process, the physiologic reserve of the patient, and the degree of clinical suspicion. Clinicians should guard against “routine” monitoring. The ideal monitoring plan allows for early detection of metabolic or physiologic derangements yet minimizes the risks for iatrogenesis, unnecessary expense to the client, and inappropriate use of ICU resources. Selection of monitoring aids should be based on reliability, expense, practicality, and the value of the information gained. Particularly when choosing invasive monitoring techniques, risk to the patient must be weighed against potential benefit. Utility of a monitoring device is maximized when clinicians are familiar with the principles of the device, how to operate it, the reliability of the measurement, the range of normal values, the indications, contraindications, and complications of the technique, and how to troubleshoot technical problems that may arise.


Although monitoring is a vital component of ICU care, it is important to remember that it is not the monitoring, alone, that is beneficial or protective, but rather the clinician’s interpretation of the data and actions based on changes in monitored parameters that are important. It is impossible for the presence of a monitoring device to alter outcome. A monitored variable is useful only if a change in that variable is linked to an intervention or therapy that affects outcome. In addition to evaluating functions or parameters pertinent to the primary disease process, the daily assessment should include surveillance for new problems, because a common cause of ICU morbidity and mortality is progressive physiologic dysfunction in organ systems remote from the site of the primary disease process. Use of a checklist has been promoted to enhance both efficacy and efficiency when caring for critically ill patients.1 Box 201-1 lists 20 parameters that should be included in the daily assessment of every ICU patient. This chapter will review these 20 parameters. Many, if not all, of these systems have been discussed in detail elsewhere in this text.



Box 201-1 Kirby’s Rule of 201


GI, Gastrointestinal; WBC, white blood count.



• Fluid balance

• Oncotic pull

• Glucose

• Electrolyte and acid-base balance

• Oxygenation and ventilation

• Mentation

• Perfusion and blood pressure

• Heart rate, rhythm, and contractility

• Albumin levels

• Coagulation

• Red blood cell and hemoglobin concentration

• Renal function

• Immune status, antibiotic dosage and selection, WBC count

• GI motility and mucosal integrity

• Drug dosages and metabolism

• Nutrition

• Pain control

• Nursing care and patient mobilization

• Wound care and bandage change

• Tender loving care


KIRBY’s RULE OF 20



Fluid Balance


Fluid balance can be extremely challenging to assess in the critically ill patient. It requires assessment of both the intravascular and interstitial fluid compartments, based on physical examination findings. These findings are integrated with knowledge of the patient’s total fluid intake and output and an understanding of the underlying disease processes.


Mucous membrane color, capillary refill time, heart rate, pulse quality, extremity temperature, central venous pressure, and systemic blood pressure can be used to evaluate vascular volume. Interstitial volume is best evaluated by mucous membrane moisture, skin turgor, packed cell volume and total solid parameters, and serial measurements of body weight. Many critically ill patients have altered capillary permeability or decreased albumin levels. These changes alter the distribution of fluid between the vascular and interstitial fluid compartments, favoring movement of fluid from the vascular to the interstitial space. In this patient population, adequate or even increased fluid in the interstitial space does not ensure normal vascular volume (see Chapter 64 and 65, Daily Intravenous Fluid Therapy and Shock Fluids and Fluid Challenge, respectively).



Oncotic Pull


Colloid osmotic pressure (COP), the osmotic pressure exerted by large molecules, serves to hold water within the vascular space. It is normally created by plasma proteins, namely albumin, that do not diffuse readily across the capillary membrane. Inadequate COP can contribute to vascular volume loss and peripheral edema. Normal COP is approximately 20 mmHg. Patients with COP values less than 15 mmHg are at risk for peripheral edema. The correlation between the refractive index of infused synthetic colloids and COP is not known. Therefore changes in refractive index cannot be used to monitor colloid administration. COP can be measured directly with a colloid osmometer; however, it is not commonly done because using the machine is labor intensive (see Chapter 64, Daily Intravenous Fluid Therapy).



Glucose


Hypoglycemia can occur rapidly and unexpectedly in critically ill patients, so blood glucose concentration should be monitored routinely. The frequency of measurement will depend on the severity of illness and the nature of the underlying disease. In critically ill patients, blood glucose should be monitored at least every 12 hours. The development of hypoglycemia in a critically ill adult patient should prompt the consideration of sepsis. In hypoglycemic patients, glucose can be supplemented in the balanced electrolyte solution or provided through nutritional support (see Chapter 69, Hypoglycemia). Studies of human ICU patients have demonstrated increased morbidity and mortality associated with hyperglycemia.2,3 Similar studies have not been performed in veterinary patients; however, the aim should be to maintain blood glucose between 80 and 140 mg/dl.



Electrolyte and Acid-Base Balance


Abnormalities in serum electrolytes are common in critically ill patients and can have devastating clinical consequences if not identified and corrected. Serum sodium, chloride, potassium, and calcium should be monitored and maintained within the normal ranges. Monitoring frequency will depend on the severity of illness, the nature of the primary disease process, and the owner’s financial commitment but may be needed as frequently as every 1 to 2 hours in patients with rapidly changing conditions. In addition, magnesium depletion has been identified as a common electrolyte abnormality in critically ill veterinary patients. Refer to the Electrolyte and Acid-Base Disturbances section of this text for a full discussion of these topics.


Measurement of acid-base status has become routine with the development of portable, affordable blood gas monitors. Venous samples are useful for evaluation of the metabolic acid-base status. Bicarbonate and base excess are used to evaluate metabolic status, and partial pressure of carbon dioxide (PCO2) is used to evaluate the ventilatory status. Interpretation of acid-base abnormalities can be aided by measurement of lactate and electrolyte concentrations. Assessment of acid-base status should be performed at least daily in critically ill patients and may be required 4 to 6 times daily in some animals.

Related posts:

  1. Deteriorating Mental Status
  2. Hyperthermia and Fever
  3. Ventilator-Associated Lung Injury
  4. Allergic Airway Disease in Dogs and Cats and Feline Bronchopulmonary Disease

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Sep 10, 2016 | Posted by in SMALL ANIMAL | Comments Off on Daily Assessment of the Critically Ill Patient

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