Chhgg

1. Intraoperative care of the
anaesthetized patient
Dyllan Omwenga
Malyun Ahmed
Kitilit Brian
Linet Sigei
Brian Otsyula

2. Induction of anaesthesia
• Inhalational induction of anaesthesia
• pt breathes increased conc.of inhaled gases by mask N2O in oxygen
• Short acting intravenous
agents:propofol,ketamine,thiopental;etomidate,followed by a muscle
relaxant(NDMR) if indicated
• Pts at risk of aspiration need rapid sequence induction

3. Airway management
• Common airway techniques:
• Mask airway(airway supported manually or with oral airway)
• Laryngeal mask airway
• endotracheal intubation(nasal or oral)
• Supraglottic airway
• Factors determining choice:airway assessment
• Risk of regurgitation or aspiration
• Need for positive pressure ventilation
• Surg.factors(location,duration,pt pos.,degree of muscle relaxation required

4. • Indications for endotracheal intubation
• Provide patent airway(oral cavity surg,or pt must be prone,airway
path
• Protect airway from aspiration
• To facilitate positive pressure ventilation

5. SADs
• supraglottic airway devices (SADs) are used with both spontaneously
and ventilated patients during anesthesia.
• Th ey have also been employed as conduits to aid endotracheal
intubation when both BMV and endotracheal intubation have failed
• . All SADs consist of a tube that is connected to a respiratory circuit or
breathing bag, which is attached to a hypopharyngeal device that
seals and directs airflow to the glottis, trachea, and lungs.
• Additionally, these airway devices occlude the esophagus with
varying degrees of effectiveness, reducing gas distension of the
stomach.

6. Oxygen
• Types of oxygen masks used include
• SimpleFace masks: deliver -5-10l/min o2 conc 35-50%
• Limitations;delivers low o2 conc
• Reservoir masks {non rebreather mask};high conc o2;10-15l/min
• Limitationsdelivers only one FiO2:1
• Venturi mask;provides high gas flow with a fixed O2 conc of 20-55%;
• Flow rate 4-15l/min,advocated for pts with severe hypoxemia

7. Maintenance of anaesthesia
• Involves use of inhaled agents(des,iso
• &sevoflurane,N2O),opiods(fentanyl,su,remi&alfentanil,,NDMR(rocuro
nium,cis-atracurium)
• The anaesthesiologist should be vigilant of problems encountered in
this phase;
• Awareness:pt on GA becomes conscious of his environment during
surg(common with CS,cardiac and trauma surgery pts
• Intraopcare with hypnotiagents;ketamines,propofol,benzodiazepines
• positioning:cosequences of positioning;dec.venous return &
CO,hypotension;careful positioning is important

8. Maintenance cont’d
• Sitting pos;ass with risk of venous air embolism
• Prone;aiway obstructed or dislodged
• Prone trendelburg &lithotomy;upward displacement of diaphragm
• Nerve injury from compression on pressure points esp ulnar
n.,brachial plexus injury,

9. • Hypothermia;has deleterious effects on cns rs etc &inc,recovery time
from effects of muscle relaxants
• Heat lost via conduction,convection,evaporation,radiation
• Loss minimized by keeping OR temp as high astolerable>21C
• ;gas humidifiers or use of low gas flow;
• warm fluids given;
• pt may need to be sedated,paralysed&mech ventilated post-op till
adequate temp is restored

10. Intraoperative monitoring:parameters
• Respiratory(airway;RR,depth,&character;oxygen saturation)
• CVS(HR&rhythm;PR&strength;mucus membrane color & CRT;Arterial
BP)
• Body temperature
• Anaesthetic depth/patient status(reflexes &muscle tone;eye
pos.&pupillary reflex activity;HR&RR;status of surg procedure)
• Equipment function(anesthetic level;vaporizer &oxygen flowmeter
settings;pressure relief valve)

11. RS
• Airway;check endotracheal tube if its kinked,slipped out or placed
deeply
• Listen for Acc.of moisture in the tube
• RR,depth &character;normal10-20bpm(chest mvts or reservoir bag)
• Increasein depth of anaesthesia results to decresed RR& tidal vol.
• Hypoventilation may result in alveoli collapse(partial)-periodic
bagging can prevent this
• Spo2;95-100%

12. CVS
• HR&rhythm;80-120bpm
• Assess via auscultation
• Bradycardia indicates excessisive anesthetic depth;response to vagal
stimulation etc
• PR,strength&quality;strong &synchronized to heartbeat
• ECG ,all pts should have intraop monitoring
• central venous catheterization,indicated for admin. of fluid to treat
hypovolemia&shock,tinfusion of caustic drugs,gaining venous access
• MM color&CRT;pale MM(bld loss,anemia,poor perfusion)blue(cyanosis due
to Resp.Failure or airway obstruction-upper)
• CRT<2s;prolonged=hypotension from excess anesthetic depth or
circ.shock,hypothermia,cardiac failure

13. Cont’d
• Arterial BP;120/80mmHg;systolic80-120mmHg & diastolic 60-
100mmHg,MAP 70-90mmHg
• Hypotension;excessive anesthetic depth;hypovolemia(hae’ge or
dehydration)hypothermia,hypoxia
• Body temperature;anesthesia will typically lowe temp

14. analgesia
• Opioids are used intraoperatively to provide analgesia
• And to reduce requirementof other maintenance drugs
• Commonly used;fentanyl,sufentanil,remifentanil &alfentanil
• Have a shorter duration of action &
• allow finer titration to provide adequate analgesia during the variable
• An opioid is admin.as a LD ,prior to induction
• MOA;activation of the Mu-1 receptors produces analgesia & kappa

15. Fluid therapy
• Intraoperative loses;bld loss is assessed by visually inspecting bld in the
suction bottles,drapes & floor(sponges 1gm=1cc of blood)
• Third space loss-loss of plasma fluid into the interstitial space due to
trauma & is estimated based on the nature of surgery;
• 2-5cc/kg/hr for minimal surg.trauma(orthopedic surgery)
• 5-10cc/kg/hr for moderate surg.trauma(bowel resection)
• 10-15cc/kg/hr major sur.trauma(AAA repair)
• Urine output is also assessed
• NS or RL are the preferred crystalloids for intraop.fluid admin &
resuscitation;provide more intravascular vol.expansion
• Given in 3-4:1ratio to the estimated blood loss unlike colloids 1:1(used
when >20% bld loss

16. Fluid therapy cont’d
• Bld products administered for specific indications;
Blood product deficit
Red cell concentrates Oxygen carrying capacity
Platelets Platelet function(quality or quantity)
Fresh frozen plasma Clotting factor deficits
Cryoprecipitate Fibrinogen
Albumin Low protein or colloid vol.replacement
Factor concentrates Single clotting factor defict(often
hereditary)

17. Reversal of anaesthesia
• This requires the offset of effects of anesthetic agents
• Achieved by administering agents in appropriate doses & time based
on anticipated length of procedure
• Anaesthesiologist relies on metabolism & excretion of drugs to
achieve offset of effect
• Active reversal of drug effect using another also plays a role
• E.g.reversal of muscle relaxation
• Extubation

18. References
• Understanding anaesthesia;Karen raymer,MD
• Outline of anaesthesia