Systematic Data Interpretation & Interventions

Now that you have assembled observational information it is time to address the recorded data and assemble a problem list. The way to write your note is to write down what you have found (examination), what has been recorded (data observation), what you are doing (interventions), and what you are planning to do along a continuum. An isolated blood pressure of 110/70 is irrelevant if you are not informed that the patient is requiring 20mg/minute of norepinephrine to maintain it.

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The most effective method of exploring patient data is to use a head-to-toe systems approach. I use the following mnemonic to do this: New (nervous system) Residents (respiratory) Can (cardiovascular) Get (gastrointestinal tract, liver and nutrition), Killed (kidneys), Even (endocrine), Surgeons (skin, extremities and wound), Lives (laboratory studies), Are (analgesia), In (infectious diseases), Danger (devices).

Neurological

Is the patient awake? If not – why not?

You have already quantified the neurological status using AVPU, this can also be quantified using the Glasgow Coma Score (GCS), Ramsay sedation score or Sedation Agitation Scale (SAS). It is my preference to use the Ramsay scale (or SAS) in patients who are being sedated, and the Glasgow Coma Score in those who are not. The data obtained includes intracranial pressure and jugular mixed venous oxygen saturation (SjO2). The interventions in this system usually involve the use of sedatives, with or without pain killing properties:

“the patient responds to verbal stimuli, his GCS is 11, his Ramsay score is 3 on propofol 10mg/minute, and fentanyl 25mg/hour.”

Sedation Scales

Respiratory

You have multiple layers of pulmonary information which need to be integrated. The examination in a ventilated patient may be less valuable than hard information such as the blood gas measure, the ventilator settings and the chest x-ray. Remember that when you are recording data it must make sense to a reader or listener:

“the patient’s blood gas on an FiO2 of 0.4 and PEEP of 10cmH2O is PaO2 77, PaCO2 44, pH 7.38, HCO3 27, Saturation 95%. His ventilator settings are pressure control of 22cmH20, inspired time of 1.5 seconds rate of 14 breaths. His tidal volumes are 450ml. His chest x-ray reveals low lung volumes, bilateral infiltrates and small bilateral pleural effusions. He requires hourly suctioning  and his sputum is thick and purulent.”

Several factors are influencing the PaO2 on the ventilator alone: the CPAP/PEEP level, the peak pressure level, duration of inspiration and the fraction of inspired oxygen (FiO2). The blood gas reveals two types of information: the PaO2 and the patient’s acid-base status. Different factors influence these:

Factors influencing the PaO2

Factors influencing the pH (acid-base balance)

Cardiovascular

Again the information gleaned from physical examination may not be as useful as the measured data. The information should be recorded in the following order: heart rate, blood pressure, CVP, PA catheter measurements.

“...his pulse rate is 100, in atrial fibrillation, on amiodarone, his blood pressure is 90/50 on dopamine 5mg/kg/minute, his CVP is 12, following volume loading of 5 litres, our target BP is MAP of 60 and CVP of 14cmH20. He has a PA catheter in situ: is PAP is 38/18, wedge pressure of 14cmH20, which correlates well with the CVP, his cardiac output is 8.0 litres and his cardiac index is 2.6 litres, again on dopamine. His SvO2 is 71%, up from 53% on admission.”

Remember what you are measuring: the mean arterial pressure is the principle perfusion pressure of all major organs except the heart. Coronary filling is determined by the diastolic pressure. The heart rate determines the time available for diastolic filling and the myocardial oxygen consumption. The CVP is indicative of venous return, and intravascular volume. The numeric value of CVP is influenced by venoconstriction and intrathoracic pressure, particularly when CPAP is applied. Thus CVP is not an isolated value, but a trend. The urinary output is the most useful direct measure of end organ perfusion. Pulmonary artery catheters (PAC) are inserted in order to measure cardiac performance, stroke volume, in response to cardiac muscle loading, end diastolic pressure. A surrogate is often used for the latter, the pulmonary capillary wedge pressure (PCWP) or the pulmonary artery diastolic pressure (PAD). PACs do not measure intravascular volume, but can be used to follow stroke volume responses to volume boluses. Similar data can be derived from non invasive devices such as the esophageal doppler monitor (EDM), or NICO (non invasive cardiac output monitor). The mixed venous oxygen saturation (SvO2) is a useful measure of oxygen consumption, and can be used to guide resuscitation efforts.

Factors influencing the blood pressure (BP)

Gastrointestinal System & Nutrition

This involves evaluation of abdomen, the gut and the liver. It is necessary to refer to the examination of the abdomen, including the wound site, if present, and data relating to inputs and outputs, and qualitative data regarding liver function.

“On examination of the abdomen, there is a midline laparotomy wound, which is healing well. Nasogastric suction is minimal. He is being fed thru a post-pyeloric feeding tube, using enteral feed at 80ml/hour, which is his goa (the feed is contains…)l. The feed is well tolerated and he is passing stool. His liver function has been normal since admission.”

It is essential to defend the absence of enteral feeding, which may require a discussion about the presence or absence of bowel sounds, which are insensitive markers of the presence or absence of ileus. You must also discuss whether or not the patient is passing flatus or bowel motion: a patient who is having bowel movements does not have an ileus. Avoid getting into a discussion about the patient’s nutritional status: intensive care patients are catabolic – they are under nourished. The only way you can arrest catabolism is to feed the patient. You cannot make the patient anabolic, so looking for markers of nutritional status is disingenuous. On the other hand, it is useful to check the patient’s nitrogen balance once fully fed, to ensure that goal nutrition is adequate.

Renal Function and Fluid Balance

The kidneys control overall fluid balance and excrete products of metabolism. The normal function of the kidneys is the ability to concentrate the urine, retain sodium and excrete excess fluid and metabolites. Two surrogate markers of renal function are used – urea, which is determined by protein catabolism, and is reabsorbed in part by the nephron, and creatinine, the serum concentration of which is determined by muscle mass and muscle turnover. Thus urinary sodium and creatinine clearance are superior measures of renal function.

“the patient is 8 litres positive since admission, 500ml positive over the last 24 hours. His urinary output is on average 35ml/hour. His urea is 20 and his creatinine is 1.8, up from 1.4 over the past 24 hours. We have sent a urinary sodium and creatinine in order to determine the nature of the renal injury.”

The patient may be on continuous hemodiafiltration (CVVHDF) or intermittent hemodialysis: if so, it is essential that you know the dialysis parameters and plan. For example, if the patient is on CVVHDF, you must know the blood flow rate, the dialysis flow rate, the amount of fluid removed per hour, the agent used for anticoagulation, and the dialysate formula.

Factors Influencing Renal Function

Endocrine

The neuro-endocrine response to critical illness is complex and fascinating, but hardly the stuff of ward rounds. Most intensivists are only interested (perhaps wrongly) in glucose control and adrenal function. It is important to note the serum glucose level, as this may become dangerously high in this patient population, and hyperglycemia is associated with worse outcome. If the blood sugar is normal due to insulin therapy, this must be projected. Likewise, patients may have absolute or relative adrenal insufficiency, usually due to chronic steroid therapy. It is essential to evaluate whether sufficient quantities of adrenal hormones are being given.

“The patient’s blood sugar is 240mg/dl, controlled on an insulin drip, currently at 5 units per hour. He is being treated with hydrocortisone at 50mg q8hours, due to chronic steroid use, related to COPD.”

Alternatively, “he is being treated with hydrocortisone 50mgq8hours due to adrenal insufficiency related diagnosed by a positive ACTH stimulation test.”
 

Extremities, wound and skin

The skin is the body’s main layer of protection, and areas frequently break down in intensive care due to pressure effects or infection. Critically ill patients are catabolic, wounds heal poorly. Likewise, surgical sites are frequent sources of misadventure. Interventions aimed at the patients extremities must be described and discussed.

“On examination of the skin and extremities, the patient has a stage 2 decubitus ulcer on his sacrum. There is some peripheral edema and the patient is being treated with sequential compression devices and enoxparin for DVT prophylaxis. The laparotomy wound site is clean and granulating.”

Labs and Hematology

The ability to make blood cells and platelets is an important prognostic factor in critical illness. Likewise it is essential to know if the patient has being requiring multiple transfusions to maintain normal homeostasis. The measurement and supplementation of electrolytes should be documented.

“His hemoglobin is 9.2 following transfusion of 4 units of red cells. His platelet count is 230 and his prothrombin time (to control) ratio is 1.2 (the INR is used only to guide warfarin treatment). Sodium is 142, potassium was 3.4, this has been supplemented, magnesium, calcium and phosphate are all within normal limits.”
 

Analgesia

In patient satisfaction surveys, inadequate analgesia is frequently cited as a complaint. Patients in intensive care are always in pain unless they are able to tell you otherwise. Most pain scales are measured as 1 to 10, from very mild pain to excruciating. Opioids are usually given as continuous infusions or patients controlled infusion pumps (PCA). In is difficult to control pain with opioids alone, and it is important to weigh up the costs and benefits of using regional blocks, non steroidals and other centrally acting analgesics such as acetaminophen.

“The patient’s pain score is 2/10 and he is being treated with a hydromorphone/bupivicaine epidural (at protocoled concentrations)  at 4ml/per hour. In addition he is receiving acetaminophen 1gq6hours, and ketorolac 15mg iv q8hours. This will be discontinued tomorrow.”
 

Infectious Diseases (microbiology)

Most intensive care patients die of multi-organ failure secondary to the overwhelming release of inflammatory mediators, vasoactive metabolites, proteases and infection. If a patient stays in intensive care long enough, nosocomial infection is inevitable. Moreover, many are admitted with systemic sepsis in the first place. Unfortunately indiscriminate antimicrobial prescribing by physicians as a “hail Mary” exercise in ICU has led to the emergence of multi-drug resistant strains of bacteria. When evaluating a patient for infection in ICU you must look for hard evidence of infection, justify your antibiotic choice and set a time limit for treatment. There is nothing more irritating than rounding on patients who are on day 10 of imipenem, with no evidence of over infection, no organisms isolated and no plan for duration of treatment.

“The patients temperature is 38.6, his white cell count is 19. He has an infiltrate on the right lower zone of his chest x-ray. A broncho-alveolar lavage was performed 2 days ago, and Pseudomonas grew. He is being treated with ciprofloxacin (dose) and gentamycin (dose). He has a penicillin allergy, and is on day 3 of 10 of treatment. We have also sent blood, urine and stool cultures.”
 

Devices

One of the inevitable consequences of critical illness is lines, drains and other hardware. You must know what devices are inserted into your patients, why they are there and for how long. It is not uncommon for pulmonary artery catheters to be removed and for the introducer to remain in situ, unused, for weeks. People die of line sepsis. If it is not necessary then it should be removed. Remember that central lines are required for measuring CVP, to administer drugs which would cause thrombophlebitis or worse peripherally (TPN, epinephrine), or where peripheral access is not possible. Lines in low pressure systems (venous) are more likely to become infected than those inserted on the arterial side (arterial lines). There is no evidence that routine changing of lines reduces the incidence of sepsis, and indeed may increase the risk of complications (e.g. pneumothorax). This does not excuse you from monitoring the age and condition of your lines and drains.

“The patient has a right radial arterial line, which is 6 days old, a right sided subclavian line, which is 4 days old, and two abdominal drains, which drained 300ml and 200ml of sero-sanguinous fluid over the past 24hours. All of the sites look clean.”

Copyright Patrick Neligan 2001-2002

Please note: these tutorials are for personal study purposes only.  They are not currently peer reviewed, and no responsibility will be taken for mistakes or inaccuracies. Reproduction of information is forbidden. All material is copyrighted by the GasWorks Group.