The Post anesthesia care unit [PACU] is designed and staffed to monitor and care for patients who are recovering from the immediate physiologic effects of anaesthesia and surgery. PACU is well equipped to resuscitate patients who are unstable while providing a tranquil environment for the “recovery” and comfort of patients who are stable.

1. POST ANAESTHESIA CARE UNIT
BY Dr. SHARATH KUMAR M.P
MODERATOR- Dr PRASHANTH
ASSOCIATE PROFESSOR
DEPT OF ANAESTHESIOLOGY

2. INTRODUCTION
• The Post anaesthesia care unit [PACU] is designed and staffed to
monitor and care for patients who are recovering from the
immediate physiologic effects of anaesthesia and surgery.
• PACU is well equipped to resuscitate patients who are unstable
while providing a tranquil environment for the “recovery” and
comfort of patients who are stable.

3. ADMISSION TO THE PACU
On arrival of a patient to the PACU, the anaesthesiologist
provides the PACU nurse with patient’s details , medical condition,
anaesthesia and surgery.

4. STANDARDS FOR POST ANAESTHESIA CARE
1. All patients who have received General anaesthesia,
regional anaesthesia or monitored anaesthesia care shall
receive appropriate post anaesthesia management.
2. A Patient transported to the PACU shall be accompanied
by a member of the anaesthesia care team who is
knowledgable about the patient’s condition.

5. 3. The patient shall be continually evaluated and treated during
transport with monitoring and support appropriate to the patient’s
condition.
4. The patient’s condition shall be evaluated continually in the PACU.
Particular attention is given to monitoring oxygenation , ventilation ,
circulation and level of consciousness.

6. POST-OPERATIVE PHYSIOLOGIC CHANGES.
Loss of Pharyngeal muscle tone –
Causes can be from effects of
A] Inhaled and i.v anaesthetics.
B] Neuromuscular blocking drugs and opioids all contribute to the
loss of pharyngeal tone in the patient In the PACU.
Pharyngeal muscle activity is depressed during sleep and the
resulting decrease in tone can further promote Airway obstruction.

7. Measures to overcome pharyngeal muscle tone.
• Opening the airway with the Jaw thrust Maneuvre or continuous
positive airway pressure (CPAP) applied via a facemask can relieve the
airway obstruction secondary to the loss of Pharyngeal tone.
• Support of the airway is needed until the patient has adequately
recovered from the effects of drugs administered during anaesthesia
and in some cases placement of oral or Nasal airway , Laryngeal mask
airway , or ETT is required.

8. RESIDUAL NEUROMUSCULAR BLOCKADE.
Residual neuromuscular blockade may not be evident on arrival in the
PACU because the diaphragm recovers from neuromuscular blockade
before the pharyngeal muscles do.
A decline in train of four ratio TOF may not be appreciated until it
reaches a value less than 0.4to 0.5
A Prospective study of over 18,000 patients who received intermediate-
acting neuromuscular drugs and their matched cohorts showed that
paralysis with inter-mediate acting neuromuscular blockade is associated
with increased risk of postoperative complications.

9. FACTORS CONTRIBUTING TO PROLONGED NON-DEPOLARZING
NEUROMUSCULAR BLOCKADE
Drugs
1.Inhaled anaesthetic drugs
2.Local anaesthetics ( lidocaine)
3.Cardiac antiarrhythmics ( procainamide)
4. Antibiotics (polymyxins ,aminoglycosides, lincosamines,clindamycin)
Metronidazole.

10. • Corticosteroids and Calcium channel blockers.
• Dantrolene
METABOLIC AND PHYSIOLOGIC STATES
• Hypermagnesia
• Hypocalcemia
• Hypothermia
• Respiratory acidosis
• Hepatic or renal failure

12. • In an awake patient clinical assessment of reversal of neuromuscular
blockade is done by checking the :-
• Grip strength
• Tongue protrusion
• Ability to lift the legs off the bed , and ability to lift the head off
the bed for a full 5 seconds.
Of all these manuevers, the 5-second sustained head lift has been
considered the standard, reflecting not only the motor strength, but
more importantly , the patient’s ability to maintain and protect the
airway.

13. Reversal can be achieved by :
Warming the patient airway support , and correction of
electrolyte abnormalities.
Use of sugammadex resulted in return of TOF ratio of greater
than 0.9 within 5 minutes in 85% of patients with no twitches on
TOF stimulation.

14. LARYNGOSPASM
Sudden spasm of vocal cords that completely occludes the laryngeal opening.
It typically occurs in the transitional period when the patient is extubated.
Although laryngospasm most likely occurs in the operating room at the time
of tracheal extubation, but can also occur in patients in PACU who are asleep
after General anaesthesia.
Management – Jaw thrust manueuver with CPAP (up to 40 cm of water)
If jaw thrust manuever fails, then skeletal muscle relaxation can be achieved
with Succinylcholine 0.1 to 1.0 mg/kg intravenously Or 4mg /kg Succinylcholine
intramuscularly can be given.

15. EDEMA OR HEMATOMA
Airway edema is caused by surgical procedures of tongue, pharynx, neck ,
thyroidectomy , carotid endarterectomy and cervical spine procedures.
So in these conditions there is extensive edema.
Mask ventilation may not be possible in a patient with severe upper airway
obstruction resulting from edema or hematoma.
So in such conditions hematoma must be evacuated and clips or sutures
released to decompress the airway.
Emergency tracheostomy will be performed when there is too much fluid or
blood that has infiltrated the tissues of pharyngeal wall.

16. OBSTRUCTIVE SLEEP APNEA
• Patients with Obstructive sleep apnea are particularly prone to
airway obstruction and hence should not be extubated until they
are fully awake and obey the commands.
• Patients with OSA are sensitive to benzodiazepines and opioids
and it can result in airway obstruction in PACU.
• Hence opioids must be avoided.

17. POST-OPERATIVE HYPOXEMIA
• Atelectasis and alveolar hypoventilation are the most important causes of
transient postoperative arterial hypoxemia in immediate post operative
ward.
• Arterial hypoxemia secondary to hypercapnia can be reversed by the
administration of supplemental oxygen or by normalizing the patient’s Paco2
by external stimulation of the patient to wakefulness.

19. PULMONARY EDEMA
Post obstructive Pulmonary edema is a transudative edema produced by the
exaggerated negative intra-thoracic pressure generated by an inspiratory
effort against closed glottis.
Treatment includes supportive and includes supplemental oxygen, diuresis and
in severe cases post-pressure ventilation of the patient’s lungs.

20. Transfusion –related lung injury.
It typically occurs within 1-2 hours after the transfusion of plasma-
containing blood products including packed red blood cell , whole blood ,fresh
frozen plasma or platelets.
Treatment for this is supportive care , supplemental oxygen and drug induced
diuresis.

22. POST OPERATIVE NAUSEA AND VOMITING
• A study conducted by Grief and colleagues randomized 231 patients
undergoing elective colon resection to receive 30%or 80% oxygen. In the
study , administration of 80% supplemental intraoperatively and
postoperatively reduced the incidence of post operative nausea to two fold.
• Kober and colleagues found that hyperoxia reduced the incidence of nausea
and vomiting fourfold compared with patients breathing air.
Aprepitant (EMEND) , a substance P antagonist blocks the neurokinin 1 (nk1
receptor) is found to be effective in high- risk patients and refractory
cases of POST-operative Nausea and vomiting.

24. • Wound infections – Supplemental oxygen appears to reduce the incidence
of surgical wound infections in patients undergoing colorectal surgery.
Recently a randomized controlled study of 300 patients in 14 Hospitals
found that patients who received supplemental oxygen had 30% reduction in
surgical site infection.
• Patients who are stable after head and neck surgery may not be candidates
for face mask oxygen because of the risk of pressure necrosis on incision
sites and microvascular muscle flaps.

25. Hemodynamic instability
• SYSTEMIC HYPERTENSION- patients with a history of essential
hypertension are at a greater risk for significant systemic hypertension
in the PACU
• Surgical procedures most commonly associated with postoperative
hypertension are carotid endarterectomy and intracranial procedures.
Factors leading to postoperative hypertension are Preoperative
hypertension , arterial hypoxemia , hypervolemia , emergence excitement,
shivering , Drug rebound , increased intracranial pressure.

26. HYPOVOLEMIA
• Systemic hypotension in the Post anaesthesia care unit is often due to
decreased intravascular fluid volume and preload.
• Common causes of decreased intravascular fluid volume in the immediate
postoperative period include ongoing third space loss of fluid.
• Inadequate intra-operative fluid replacement especially in patients who
undergo major intra-abdominal surgeries.
• Loss of sympathetic nervous system as a result of neuraxial blockade.
• Ongoing bleeding should be ruled out in patients with hypotension who have
undergone surgical procedure in which significant blood loss is possible.

27. DISTRIBUTIVE ( DECREASED AFTERLOAD)
• Reasons for distributive shock in post-operative room are
• Iatrogenic sympathectomy secondary to regional anaesthetic techniques.
• Critical illness and sepsis.
• A high sympathetic block to T4 decreases vascular tone and block the
cardioaccelerator fibres, if not treated promptly , then the resulting
bradycardia with hypotension leads to cardiac arrest.
• Vasopressors – phenylephrine and ephedrine are used in hypotension caused
by residual sympathetic block.
• Ephedrine 5-10mg i.v

28. • Allergic anaphylactic reaction may be the cause of hypotension secondary
to allergic reaction.
• Epinephrine is the drug of choice to treat hypotension secondary to
allergic reaction.
• If sepsis is the cause of hypotension in the PACU, then blood should be
collected for culture and empirical antibiotic therapy should be initiated
before shifting the patient.
• Vasopressin ( 0.01 – 0.05unit/min) improves mean arterial blood pressure.

29. CARDIOGENIC
MYOCARDIAL ISCHEMIA- interpretation of changes in the ECG in the
PACU is influenced by patient’s cardiac history and risk index.
• In patients at low risk younger than 45 years of age with no cardiac
history and the only risk factor ie Post-operative ST segment changes on
the ECG , do not usually indicate myocardial infarction.
• Causes of ST changes in patients at low risk include anxiety , esophageal
reflux , hyperventilation and hypokalemia.
• Whereas in high risk patients with known cardiac disease any ST or T wave
changes , Serum troponin levels be checked and further managed.

30. CARDIAC DYSRHYTMIAS.
• TACHYCARDIA- causes of perioperative sinus tachycardia are :-
• Pain.
• Agitation ,hypoventilation with associated hypercapnia, hypotension ,
hypoglycemia fever or infection ,hypovolemia and shivering.
• Hyperthyroidism , pericarditis , pericardial tamponade , malignant
hyperthermia.
• Treatment includes -correction of underlying cause and treatment with i.v
beta blockers.

31. RENAL DYSFUNCTION
OLIGURIA
Intravascular volume depletion – the most common cause of oliguria in the
immediate post-operative period is the depletion of intravascular fluid
volume, in this regard, a fluid challenge (500 to 1000ml) of crystalloid is
usually effective.
volume resuscitation to maximise renal perfusion is particularly important
to prevent on going ischemic injury and development of acute tubular
necrosis.

32. Post operative oliguria
PRE-renal causes
• Hypovolemia can happen when
there is bleeding,sepsis , third
space loss , inadequate volume
resuscitation
• Hepatorenal syndrome
• Low cardiac output
• Renal vascular obstruction
• Intraabdominal hypertension.
• RENAL
• Ischemia ( acute tubular
necrosis)
• Radiographic test dyes
• Rhabdomylosis
• Tumor lysis
• Hemolysis
post- renal causes are –
surgical injury to the ureters
Obstruction of the urters with
clots or stones. Urinary catheter
obstruction

33. Post operative urinary retention
• Post operative urinary retention can cause bladder overdistension and
permanent detrusor damage. USG can measure bladder volume and identify
urinary retention in the PACU
• Urinary retention is defined as bladder volume greater than 600 ml in
conjunction with an inability to void within 30 minutes.

34. • Alkalization of the urine with sodium bicarbonate has shown to provide
additional protection.
• 154 meq/l should be infused at a rate of 3ml/kg/hr for 1hr before injection
of contrast agent followed by 1ml/kg/hr for 6hrs.
INTRAABDOMINAL HYPERTENSION
• Elevated intrabdominal hypertension can impede renal perfusion and leadto
renal ischemia and post-operative renal dysfunction
• Abdominal compartment syndrome is defined as IAP greater than 20 mmhg
with / without abdominal perfusion pressure less than 50 mmhg

35. BODY TEMPERATURE AND SHIVERING
Brain and spinal cord do not recover simultaneously from general
anaesthesia. The more rapid recovery of spinal cord function is thought to
result in uninhibited spinal reflexes exhibited as clonic activity.
Ondansetron and clonidine have shown to be effective in abolishing
shivering.
Meperdine 0.35 to 0.4 mg/kg is most commonly used.

36. DELIRIUM
• Approximately 10% patients older than 50 yrs of age who undergo
elective surgery will expreince some degree of post operative delirium
within the first 5 postoperative days.
• The incidence is significantly higher in hip fracture, bilateral knee
replacement
• The American psychiatric association defines delirium as acute change in
cognition or disturbance of consciousness that cannot be attributed to a
pre-existing medical condition , substance intoxication or medication.

37. • Persistent postop delirium is generally seen in older adult
patients more than 70 yrs
• Other risk factors are alcohol abuse , history of delirium
• Management –
• Patients who are severely agitated may require restraints to
control their behaviour and to avoid self inflicted injuries.
• Sedatives are used.

38. Delayed awakening
• Residual sedation from drugs used during anaesthesia is the most
important frequent cause of delayed awakening in the PACU
• Naloxone 20-40 microgram Is used to antagonize the opiod induced
analgesia
• Physiostigmine is used to reverse the central nervous system sedative
effects of anticholinergic drugs especially scopolamine.
• Flumazenil 0.2mg is a specific antagonist for the residual depressant
effects of benzodiazepines.

39. DISCHARGE CRITERIA
• In 1970 Aldrete and kroulik developed post anaesthetic scoring
system to monitor recovery
• A score 9 out of 10 is considered adequate for discharge from
the PACU

41. THANK YOU