Neurological, Systemic & Pleural Monitoring

Objectives - Review neurological and systemic monitoring in the ICU, then connect pleural emergency procedures with monitoring responsibilities before and after intervention.

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Neurological Monitoring

Neurologic Exam

A neurologic exam may include:

• History
• Mental status
• Pupillary response
• Eye movement
• Corneal response
• Gag reflex
• Respiratory rate and pattern
• Motor and sensory evaluations

Glasgow Coma Scale

The Glasgow Coma Scale, or GCS, is the most widely used scoring system for acute neurologic disorders.

It is based on three elements:

• Eye response
• Motor response
• Verbal response

Intracranial Pressure

Intracranial pressure, or ICP, is a pressure measurement of cerebrospinal fluid in the space between the skull and brain. It is measured by inserting a catheter capable of measuring pressure.

Indications:

• Life-threatening intracranial hypertension
• Infection
• Assess effects of therapy to reduce ICP

ICP Monitoring Techniques

ICP and CPP Measurements

Formula:

CPP = MAP - ICP

The source uses MAP of 93 mm Hg from an assumed blood pressure of 120/80.

Interpretation

Increased ICP is dangerous:

• 15 to 20 mm Hg begins to compress the capillary bed
• 30 to 35 mm Hg impedes venous drainage and edema begins in uninjured tissue
• More than 50 mm Hg causes cerebral ischemia

Decreased CPP is dangerous. If CPP is 0, perfusion stops and the brain dies.

The source recommends initiating treatment if ICP is greater than 20 mm Hg.

Therapy to Reduce ICP

Therapy concepts from the source:

• Hyperventilation to target PaCO2 of 25 to 30 torr
• Hyperventilation temporarily decreases ICP through cerebral vasoconstriction
• Effect may last minutes to hours and should be discontinued after 48 hours
• Lower jugular venous pressure
• Avoid neck flexion, head turning, or trach ties that are too tight
• Minimize increases in central venous pressure
• Keep head of bed elevated at least 30 degrees
• Minimize straining, retching, and coughing
• Minimize PEEP
• Use sedation and analgesia, including narcotics and benzodiazepines
• Avoid hypotension
• Use osmotic agents such as mannitol and hypertonic saline to remove fluid from the brain

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Other ICU Monitoring

Renal and Kidney Function

The kidneys filter waste products and regulate volume and electrolytes.

Renal monitoring includes:

• BUN
• Creatinine
• Potassium
• HCO3
• Urine volume

Urine volume reflects kidney perfusion.

• Polyuria: urine output greater than 3 L daily
• Oliguria: urine output less than 0.4 L daily

Liver Function

The liver detoxifies waste from:

• Metabolism
• Digestion
• Poisons

Indications for liver function evaluation include:

• Abdominal pain
• Jaundice
• Unexplained fever
• Nausea
• Weight loss

Global Monitoring Indices

Global monitoring indices provide:

• Estimate of illness acuity
• Estimate of mortality risk
• Better understanding of treatment effectiveness
• Support for developing treatment standards

ICU scoring systems are collected on the first day. APACHE stands for Acute Physiology and Chronic Health Evaluation. APACHE II is designed to measure disease severity for adult patients admitted to intensive care units. Higher scores mean more severe illness and higher risk of death.

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Pleural Diseases and Procedures

Pleural Procedure Overview

This section covers:

• Pneumothorax treatment
• Needle decompression
• Chest tube thoracostomy

Needle Decompression

Needle decompression is indicated for tension pneumothorax.

Contraindications:

• Local skin infection at proposed insertion site
• Coagulation disorder

Equipment:

• Cleansing solution
• 14-gauge or larger needle with catheter
• Tape

Procedure:

• Use the second intercostal space at the mid-clavicular line
• Clean the area with iodine solution
• Insert a 14-gauge or larger needle attached to a catheter perpendicular to the chest
• Needle should be 5 to 8 cm long depending on muscle and fat tissue
• Go over the top of the rib because veins, arteries, and nerves run beneath ribs
• Advance until a hissing sound is heard
• The hissing sound is air leaving the pleural space
• Remove the needle while keeping the catheter in place
• Secure the catheter to the patient's body

Chest Tube Thoracostomy

A chest tube thoracostomy places a tube into the pleural space to remove air, blood, or pleural fluid from the thoracic cavity.

Indications:

• Pneumothorax that is recurrent, persistent, under tension, or bilateral
• Any pneumothorax in a patient on positive pressure ventilation
• Hemothorax
• Pleural effusion
• Emphysema
• Chylothorax

Contraindications:

• Relative: local skin infection at insertion site
• Relative: coagulation disorder
• Absolute: none

Equipment:

• Chest tube
• Chest tube insertion kit
• Sterile gloves, gown, mask, and drapes
• Anesthetic, such as 1% lidocaine
• Drainage system
• Heimlich valve

Chest Tube Equipment

Chest tubes are sized in French units. Sizes range from infants to adults. Small tubes are used for air, and larger tubes are used for fluid. Tubes may be curved or straight and made of PVC or silicone.

A chest tube insertion kit may include:

• Scalpel and blade
• Two straight hemostats
• Suture
• Suture scissors
• Needle driver
• Petroleum gauze
• 20-mL syringe
• 18-gauge needle

Drainage Systems

A drainage system collects air, blood, and effusions.

Components:

• Collection chamber
• Water seal chamber
• Suction control chamber

How drainage works:

• Expiratory positive pressure from coughing or Valsalva helps push air and fluid out
• Gravity helps fluid drainage when the system is below chest level
• Suction can increase how quickly air and fluid are pulled from the chest

Bottle Systems

Heimlich Valve

A Heimlich valve is a one-way rubber flutter valve that prevents air from entering the pleural space.

• Proximal end attaches to the chest tube
• Distal end connects to suction or remains open to atmosphere

Advantages:

• Small
• Lightweight
• Allows ambulation

Disadvantages:

• Can only drain air
• Fluid can cause the rubber to stick and stop working

Chest Tube Placement and Positioning

External landmarks include:

• Clavicle
• Ribs
• Mid-axillary line

Placement depends on what is being drained:

• Gas collects in upper chest areas
• Fluid accumulates in gravity-dependent areas

Fluid-filled pleural space:

• Fifth, sixth, or seventh intercostal space
• Posterior of the axillary line

Air-filled pleural space:

• Third or fourth intercostal space
• Anterior of the axillary line

Positioning:

• Place patient supine
• For anterior axillary insertion, head of bed may be elevated 30 to 60 degrees
• Elevation lowers the diaphragm and decreases risk of injury to the diaphragm, spleen, or liver
• Raise the patient's arm above the head on the insertion side
• Apply supplemental oxygen
• Note baseline vital signs and SpO2
• Continue monitoring heart rate, color, and oxygen saturation

Post-Procedure Monitoring

After placement:

• Obtain chest x-ray
• Verify correct catheter placement
• Check for residual or reaccumulated air or fluid

Monitor water-seal chamber:

• Water level rises and falls with respirations
• With active pneumothorax, bubbling is continuous
• As pneumothorax resolves, bubbling becomes intermittent during inspiration
• When pneumothorax is resolved, bubbling stops

Monitor:

• Vital signs
• SpO2
• Respiratory distress changes
• Breath sounds
• Color and amount of drainage

High-Yield Review