PROPOFOL

Propofol is a short acting intravenous sedative-hypnotic. Propofol has several advantages over other anesthetic agents.

The main advantages of propofol include

1.  rapid induction of general anesthesia

2.  rapid return of consciousness

3.  minimal residual effect on the central nervous system

4.  decreased incidence of nausea and vomiting.

Use:

1.  as an anesthetic induction agent

2.  maintenance of general anesthesia

3.  for short term sedation in intensive care patients that are intubated and mechanically ventilated.

Propofol is formulated in an emulsion as a1% solution. The emulsion contains soybean oil, glycerol, and egg lecithin (derived from egg yolk).The emulsion may cause pain with injection. The emulsion supports bacterial growth and strict aseptic technique must be carried out. When a vial is opened the contents should be used within 6 hours. The rest of the contents should be discarded. Never share the same medication with other patients. The date and time, of when propofol was drawn up, should be recorded on the syringe to avoid administering it after 6 hours.

Effects:

• Propofol interacts with gamma-aminobutyric acid (GABA), the principle inhibitory neurotransmitter in the central nervous system.

• The high lipid solubility of propofol is responsible for its rapid onset. Propofol has ashort distribution half life, allowing for rapid awakening.

• The liver is responsible for removing and metabolizing propofol. The kidneys are responsible for excreting the metabolites.

• Onset of action for propofol is 40 seconds.

The peak effect is 1 minute.

The duration ofaction is 5-10 minutes.

• The effects of propofol on the cardiovascular system include a decreased systemicvascular resistance (vasodilatation), decreased contractility of the heart, and decreased preload. These factors cause a decrease in blood pressure. Severe hypotension may be seen in patients who are dehydrated, actively bleeding, elderly, and/or those with poorheart function.

• The effects of propofol on the respiratory system include a dose dependant depression of ventilation and apnea.

Propofol can easily and rapidly cause an airway obstruction. It also alters the normal respiratory responses to hypoxia and hypercarbia. When administering propofol airway equipment should be immediately available including a bag-mask-valve device or anesthesia circuit, oral airways, oxygen, and intubating equipment.

• Propofol solutions that contain sulfites as a preservative should not be administered to asthmatic or actively wheezing patients. Sulfites can cause bronchoconstriction.

• Propofol may cause spontaneous movements and movements that look like tonic-clonicseizures.

• Pain is often associated with injection. A large vein should be used. Smaller veins, such as those on the dorsum of the hand, are often associated with pain. To reduce pain 2 -5 ml of 1% lidocaine can be administered immediately prior to the induction dose ofpropofol.

• Reduced doses should be used in the elderly and those that are dehydrated.

Dose:

• Adults: 2-2.5 mg/kg slowly over 30 seconds for induction of anesthesia.

For maintenance ofanesthesia a continuous infusion of 0.1-0.2 mg/kg/min or alternatively intermittent bolus of20-50 mg

.• Children: 2.5-3.5 mg/kg slowly over 30 seconds for induction of anesthesia.

For maintenance of anesthesia a continuous infusion of 0.125-0.3 mg/kg/min. Contraindications:

• Do not use in hemorrhaging patients.

• Do not use in patients with poor heart function.

• Do not use in patients that are allergic to egg yolks and soy products.

• Administration of propofol for cesarean section may be associated with neonatal depression.

• Not recommended for patients with increased intracranial pressure.

Medications Used in Anesthesia

1. Three components to complete a general anesthetic: amnesia, analgesia, and muscle relaxation.

2. Inhalation anesthetics are used to induce general anesthesia in pediatric patients, as well as maintain an anesthetic during surgery for adult and pediatric patients.

3. Induction agents (i.e. propofol, thiopental sodium, methohexital, andketamine) are used to induce general anesthesia by the intravenous route. Propofol can be used as an infusion to maintain general anesthesia. Ketamine can be used by the intravenous route to maintain general anesthesia by administering additional boluses.

4.  Muscle relaxants: Depolarizing muscle relaxants include succinylcholine. Nondepolarizing muscle relaxants include pancuronium, vecuronium, atracurium, and rocuronium. These medications aid in muscle relaxation for intubation and surgical relaxation. 

5.  Analgesics include opioid and non-opioid medications. These medications are important in providing analgesia for the patient during and after the anesthetic. Opioid agonist-antagonists are used to treat mild pain.

6.  An opioid antagonist (i.e. naloxone) is useful when an overdose of an opioid occurs.

7.  Anti-anxiety medications(i.e. midazolam or diazepam) are useful in the preoperative period to help calm the patient. They are also useful in providing amnesia so the patient will not have recall.

8.  Anti-nausea medications reduce nausea and vomiting in the postoperative period. Nausea and vomiting is a common complication of general anesthesia.

9.  Vasopressors (i.e. ephedrine) are useful in the treatment of hypotension. Resuscitation medications are used if the patient experiences a cardiac arrest or life threatening bradycardia

( atropine).

Anesthesia

 Anesthesia

Anesthesia  is medicine to make you comfortable during surgery or a procedure. There are many types of anesthesia. The anesthesia medicine may be given in your IV, through a face mask, or through a tube in your nose or throat. It can also be given as a shot in your back or as a shot in the area where you will have surgery. The type of anesthesia you may have depends on the type of surgery or procedure you are having. You and your caregiver will decide which type of anesthesia is best for you. Following are some of the types of anesthesia.

Types Of Anesthesia

• General Anesthesia:
  
  
  
  
• This medicine is used to keep you completely asleep during surgery. General anesthesia can be used for most procedures or surgeries. The medicine may be given as a liquid in your IV. It may also be given as a gas through a face mask, endotracheal tube, or a laryngeal  mask airway.
  
  
• An endotracheal tube or "ET" tube is put into your mouth or nose and down your throat into your lungs. The ET tube helps protect your windpipe during surgery. The laryngeal mask airway is also known as LMA. This is a tube with a small mask on the end that fits into the back of your throat instead of down your windpipe. The small mask is filled with air. The ET tube and the LMA allow you to breathe in oxygen or anesthesia gas during surgery.

• Epidural Anesthesia: This is medicine used to numb you from about the nipple line to the waist and down. While lying on your side or sitting up, a catheter (tiny tube) is put into your back through a needle. The needle is then taken out but the catheter is left in place to give you more medicine if needed. You are awake during surgery but may be given medicine in your IV so that you are sleepy. Your lower body is numb and you may be able to move your legs but should not feel pain. Feeling returns to your legs when caregivers stop putting medicine in the catheter and when the medicine wears off. Epidural anesthesia is good for procedures below the waist. Epidural anesthesia can give longer lasting pain relief than spinal anesthesia.
  
  
• Interscalene Block: This medicine is given as a shot in your neck to numb your shoulder and arm. You are awake during surgery but may be given medicine in your IV so that you are sleepy. This kind of anesthesia may be given in addition to medicine to keep you completely asleep during surgery. You may still feel pressure or pushing during surgery but should not feel pain. Feeling returns when the medicine wears off.
  
  
• Intravenous (IV) Regional Anesthesia: This is medicine put into an IV in the injured arm or leg. A pressure cuff is put on your upper arm or leg. The pressure cuff is tightened after caregivers tightly wrap your arm or leg with a stretchy bandage. This cuff keeps the medicine in the arm or leg so you do not have pain. You are awake (but may be sleepy) during surgery. You may also be given medicine in your IV so that you are sleepy. This type of anesthesia may be called a Bier block if done on your arm. IV regional anesthesia can be used for many kinds of surgeries or procedures on your arm or leg.
  
  
• Local Anesthesia: This is medicine given before a procedure or surgery to dull the pain. It is usually given as a shot in several places in and around the surgery area. The shot helps to numb the nerves in that area. This medicine can sometimes be given as an ointment or spray. Tell your caregiver if you are allergic to any numbing medicine, such as "novocaine" or "lidocaine." You are awake during the surgery or procedure. Local anesthesia is best used for tests, procedures, or surgeries where a lot of pain is not expected.
  
  
• Peripheral Nerve Block: This type of anesthesia is medicine put into your arm or leg through a shot. Your arm or leg will be numb for 4 to 18 hours depending on the type of medicine used. You are awake (but may be sleepy) during surgery. You may also be given medicine in your IV so that you are sleepy. This type of block is also called an axillary block if the anesthesia is given in your armpit. This anesthesia can be used for many types of surgery on the arms or legs.
  
  
• Saddle Block or Caudal  Anesthesia: This is medicine used to numb you below the waist. You may lie on your abdomen (belly) while your caregiver puts a shot of medicine in the lowest part of your spine. You may lie on your back with your legs up in leg holders (stirrups). You are awake during the surgery but may be given medicine in your IV so that your are sleepy. Saddle block or caudal anesthesia is used for procedures or surgeries of the rear end or legs.
  
  
• Spinal Anesthesia: This is medicine put into your back through a shot while lying on your side or sitting up. You are awake during surgery but may be given medicine in your IV so that you are sleepy. You are numb from about the nipple line to the waist and down. How high the numbness goes depends on where your surgery will be. You are not able to move your legs when the medicine starts to work. You can move your legs in 1 to 4 hours when the medicine wears off. Spinal anesthesia is best for surgeries below the waist.