Intensive care unit

• Intensive Care Unit (ICU)

  The hospital facility within which the highest level of continuous patient care and treatment is provided
• ICU

  • Approximately 1-2% of acute beds
  • Organized usually into units of 4-8 beds as this is considered to be the optimal size
  • Each bed area is supplied with oxygen and piped suction (two outlets per bed), medical compressed air and sometimes nitrous oxide (or Entonox)
  • At least 12 electric power sockets
  • Connected to the emergency standby generator
  • Sufficient local storage space to make the nurse self sufficient for common procedures, such as administration of drugs and tracheal aspiration
  • Each bed area should be equipped with self-inflating resuscitation bay to enable the staff to maintain artificial ventilation in case the mechanical ventilator fails
• Who should be admitted to the ICU
• ICU Staffing

  • Consultant oversees
  • Roles of the ICU resident
• Communication

  • Therapeutic function
  • Assessment of patients
• Hypoxaemia

  PaO2 < 7-8kpa
• Hypercapnia

  • PaCO2 > 7kpa (normal range 4.7 - 5.3kpa, 45-50mm/hg)
  • Or if PaCO2 increases by more than 2kpa above the patient's usual level
  • When respiratory rate is > 45 breaths/min for more than 1hr
• Some causes of hypoxaemia

  • Pulmonary oedema
  • Asthma
  • Chronic bronchitis
  • Emphysema
  • Pneumonia
  • Pulmonary confusion
  • Retained secretion
• APACHE

  Acute Physiology and Chronic Health Evaluation
• Conditions requiring ICU admission

  • Surgical
  • Neurosurgery
  • Thoraco-abdominal gastrectomy
  • Major vascular surgery
• Artificial ventilation

  • Instituted when PaCO2 > 7kpa (normal range 4.7 - 5.3kpa, 45-50mm/hg)
  • Or if PaCO2 increases by more than 2kpa above the patient's usual level
  • When respiratory rate is > 45 breaths/min for more than 1hr
• Causes of inadequate spontaneous ventilation

  • Respiratory centre - Brain injury
  • Pharmacological depression
  • Upper motor neuron - High spinal damage (above C4)
  • Lower motor neurons - Poliomyelitis, Polyneuritis, Tetanus
  • Neuromuscular junction - Myasthenia gravis, Neuromuscular blockers
  • Respiratory muscles - Myopathies, Dystrophies
  • Chest wall deformity - Kyphoscoliosis, Bursechars, Rib fractures
  • Lungs - Reduced compliance, Pulmonary fibrosis, ARDS
  • Airways - Increased resistance, Upper airway obstruction (Epiglottitis), Lower airway obstruction (Asthma, Bronchitis, Emphysema)
• Institution of mechanical ventilation

  1. Tracheal intubation

  2. Direct intra-arterial cannulation (Radial, brachial, dorsalis pedis or femoral artery)

  3. Percutaneous arterial cannulation to monitor arterial pressure and give ready access to arterial blood samples
• Central venous pressure (CVP)

  • Measured from a catheter introduced into the superior vena cava or right atrium and connected to either a water or electronic manometer
  • Normal value = 8-12mmHg
• Pulmonary artery pressure

  Measured using a flow directed catheter
• Information gained from measurement of pulmonary capillary wedge pressure permits distinction between pulmonary oedema from high left atrial pressure and that caused by increased permeability of pulmonary capillaries
• Brain death

  • Irreversible cessation of all brain function
  • Spinal cord function below C1 may be present
• Blood pH = 7.35-7.45 = 7.4
• PaO2 = 80-100mmHg = 90mmHg
• PaCO2 = 35 - 45mmHg = 40mmHg
• HCO3 = 22-26mg/l = 24mmHg
• SaO2 = 93- 100%
• 1kpa = 7.5mmHg
• Brain death criteria

  • Coma
  • Absent motor posturing (spinal cord reflexes may be preserved in some patients)
  • Absent brain stem reflexes, including the papillary, cornea, vestibuloocular (caloric), and gag (and/or cough) reflexes
  • Repeating the examination (not less than 2hr apart is optional)
  • At least 2 physicians must certify
• Confirmatory tests for brain death

  • Isoelectric electroencephalogram
  • Absent brain stem auditory evoked potential
  • Absence of cerebral perfusion as documented by angiographic, transcranial Doppler or radioisotopic studies
• Brain death criteria can be applied only in the absence of hypothermia, hypotension, metabolic or endocrine abnormalities, neuromuscular blocking agents, or drugs known to depress brain function
• A toxicology screen is necessary if sufficient time since admission (at least 3 days) has not elapsed to exclude a drug effect
• Established brain death gives relief from unjustifiable hope, prolonged anxiety and financial burdens on families and society
• Brain death also allows more efficient utilization of medical resources and potentially allows the harvesting of organs for transplantation
• Brain death may be helpful particularly in patients with multiple injuries and pulmonary problems, severe septicemia or actual or incipient left ventricular failure