Perioperative Events

CP40042010-2011

Dr P Chalmers

Objectives

• Fluid management• Blood loss resuscitation• Electrolyte imbalance• Critical events Sudden life threatening events

Hypoxia Collapse Hypotension +/-impaired consciousness

• Respiratory Insufficiency/depression• Cardiac events• Shock hypovolaemic/septic• Anaphylaxis

Fluid replacement• Replace existing deficit: 50% deficit in 1st hr, 25% in 2nd hr, 25% in 3rd hr• Maintain fluid balance 2mls/kg/hr• Replace surgical loss: no trauma nil minimal trauma superficial procedure 4ml/kg/hr moderate eg hernia 6ml/kg/hr major abdo,thoracic surgery 8-15mls/kg/hr blood transfusion blood loss>20%EBV

EBV =70mls/kg adult 5L

Estimated blood lossesClass 1 Class 2 Class 3 Class 4

Blood loss (mls) <750 750 -1500 1500 - 2000 >2000

Blood loss % blood vol <15% 15 – 30% 30 – 40% >40%

HR <100 >100 >120 >140

BP Normal Normal Decreased Decreased

Pulse pressure Normal /inc Decreased Decreased Decreased

RR 14-20 20-30 30-40 >35

urine output ml/hr>30 20-30 5-15 negligible

CNS/mental status Slightly anxious Mildly anxious Anxious, confused Confused, lethargic

Fluid replacement Crystalloid Crystalloid and/or colloid

Crystalloid, colloid and blood

Crystalloid, colloid and blood

Fluid Rescucitation

• ADULT 1-2I of rapid crystalloid infusion

• (PAEDIATRIC 20ml/kg)

• Then assess response

Responses to initial fluid resuscitation

Rapid response

Transient response

No response

Clinical assessment

Vital signs return to normal

Haemodynamic improvement not sustained

No change in cardiovascular instability

Estimated blood loss

10-20% 20-40% >40%

Fluids Crystalloid

+/- colloid

Crystalloid, colloid and blood

Blood

Blood prep G&H +/- Xmatch

Type-specific Emergency blood

Electrolyte Imbalance

• Hyponatraemia <130mmols/l

• Hypernatraemia >145mmol/l

• Hypokalaemia <3.5mmols/l

• Hyperkalaemia >5.6 mmols/l

Electrolyte Imbalance

Clinical situations more likely to occur in the perioperative period

Hyponatraemia

Causes: Diuretics GIT lossesBurnsCorticosteroid withdrawal

Cardiac failureTURP

Excess dextrose infusionSIADH: postoperative pain, Lung infection+COPD

Hyponatraemia• <130mmols/l: lethargy• <125mmols/l: confusion• <110mmols/l: coma• +/- GIT symptoms

• Hypovolaemic: loss of Na + H20 R/ 0.9% NaCl

• Normovolaemic: loss of Na + rel increased water

R/ water restriction

• Hypervolaemic: inc in body Na and H20

R/ diuretics and water restriction

Correction of electrolyte disorders

Hyponatraemia Aim for a change of 0.5-1mmol/L/hr

Na requirement=TBW X(target Na-actual Na)

Beware central pontine myelinolysis

Hypernatraemia

• >145mmols/l relative water deficit

Causes• Elderly water deprivation• Hyperosmolar diabetic coma• Diabetes Insipidus head injury

• S&S thirst irritability, hyperreflexia, seizure, coma

• +/- pulm oedema

Hypernatraemia

• Hypovolaemic R/ 0.9%NaCl then water• Hypervolaemic R/ Diuretics• Normovolaemic R/ 5% dextrose or water• (Desmopressin for DI)

Aim for a change of 0.5 - 1mmol/L/hr Beware cerebral oedema

HYPOKALAEMIA

• <3.5MMOLS/L

CAUSES:

Diuretics

• GIT losses

• Diabetics on insulin

• Beta agonist meds

Hypokalaemia

• Poor muscle tone <2mmols/l Resp failure

• Intestinal ileus

• Tachyarrthymias

• ECG U waves, flat T,s

Correction of electrolyte disorders

• Hypokalaemia

• <2.5mmols/l R/ 20-40mmols KCl in I litre N saline over 8Hrs (replace at 30mmols /hr max with ECG monitoring)

• 2.5-3.5mmols/L oral replacement therapy 80-120mmols/day

Hyperkalaemia

• >5.6mmols/l

• Rhabdomyolysis

• Burns

• Suxamethonium

• Renal failure

• ACE inhibitors

• Diuretics spironolactone

Hyperkalaemia

• peak T wideQRS prolonged PR loss of P waves

• Tachyarrthymias

• Cardiac arrest

• Poor muscle tone

• N & V diarrhoea

Hyperkalaemia

• <6mmols/l restrict K

• >6.5 mmols/l or ECG changes

10 units Insulin and 50ml 50%dextroseCalcium Gluconate 10mls 0f 10% over 2 min ß agonistsK binding resinDialysis

Critical events

Critical events

SUDDEN ONSET OF:• HYPOXIA and/or• CARDIOVASCULAR COLLAPSE and/or• IMPAIRED CONSCIOUSNESS

• (primarily resp :hypoxia before collapse• Primarily cardiovas: pt unwell, signs of impaired

peripheral perfusion, pallor clammy anxious, restless, hypotension then hypoxia)

Initial Management

• Assess level of consciousness

• A airway

• B breathing

• C circulation

• Respiratory depression: RR <10/min SaO2 <90%

• Respiratory obstruction: silent /stridor /

gurgling sounds

• Impaired muscle tone: shallow respirations

poor muscle tone

Blood Gases

Normal Respiration(on room air): PaO2 12-14.7kPa PaCO2 4.53 -6.1kPa

Respiratory Insufficiency: PaO2 <13kPa on O2

PaCO2 >6 kPa

Respiratory failure: PaO2 <8kPa PaCO2 >6.7 kPa

Cardiovascular Instability Shock

• Dehydration

• Inadequate fluid replacement

• Blood loss

• Sepsis

Patient Sketch

• 55 yr old male following open cholecysyetectomy history of asthma and hypertension

• Onset of resp distress, L sided chest pain worse on inspiration

• Cyanosis, confusion,tachycardia, hypotension

Differential diagnosis

• Tension pneumothorax

• PE

• AMI +/-arrthymias

• Aspiration pneumonia

• VT

Aspiration Pneumonia

• Particulate material

• Volume

• pH <7.0 chemical burn of the airway and chemical pneumonitis

• Infective pneumonia

• Anaerobes pseudomonas

• CPAP bronchodilators +/-antibiotics

Patient Sketch

• 40 year old male with anteroposterior resection of sigmoid colon and rectum for carcinoma

• 2hrs postop

• Anxious, pale, sweaty,

• RR 22/min

• HR 110/min BP120/80 85/60

• SaO2 94%

Patient Sketch

• Female following stab wound in abdo with a penetrating injury of the colon

• 2 days postop. Feeling unwell,fully conscious and orientated, looking flushed, warm clammy extremities

• Tachypnoea

• PR 110/min BP 110/80

• Temp 38.5

• WBC 3.8x109/l

SIRSSystemic Inflammatory response syndrome

• Tachypnoea >18/min

• Tachycardia >100/min

• Temp <360C or>380C

• WBC <4x109/l or >12 x109/l

Overview of MOF and care of the critically ill patient

• Monitoring

• Bloods

• Systemic MO care

• Management of underlying cause

Patient Sketch

• Stridor

• Facial Swelling

• Pt receiving iv antibiotics/difene

Anaphylaxis

• ABC• Stop administration of the trigger if applicable• Call for help• Oxygen• Adrenaline 50micrograms every 30sec (0.5mls

of1:10,000)

OR 0.5 - 1mg im every10min)• IV access

Subsequent management

• Antihistamine chlorphenamime10-20mg slow iv• SteroidsHydrocortisone100-300mg iv• Consider cardiovascular support

adrenaline/noradrenaline ivi 0.05 – 0.1 μgram/kg/min (4-8mls/hr of 6mg in 60mls saline)

• BGA• Consider Bronchodilators

• (Consider:Autoimmune assay Epipen Medic alert bracelet)

Critical events

• Airway obstruction tongue/ larnygospasm/oedema• Delayed resp depression due to intrathecal /epidural

/iv/im opioids• Inadequate reversal of muscular blockade• Aspiration pneumonia• Pneumothorax• Pulmonary Embolism• Pulmonary oedema• Myocardial ischaemia/infarction / arrthymias• CVA• Hypovolaemic shock• Septic Shock• Anaphylaxis

Head Injury

• Concern for anaesthetist• To prevent secondary damage due to

hypoxia, hypercarbia and impaired cerebral perfusion

• Assessment of LOC

AVPU

GCS 8 or lessintubationScottish Intercollegiate Guidelines Network SIGN

Guideline 46 Early Management of Head Injury http://www.sign.ac.uk/guidelines/fulltext/46/index.html

Principles of managementA. Maintain good oxygenation

Increased FiO2 SaO2 >95% Hb>10g/dlIntubation and ventilation: if GCS 8 or less

and/or PaO2 <13kPa on oxygen and/or PaC2 <3.5kPa or > 6kPa

B. Maintain cerebral perfusionCPP=MAP-ICP (70 mm Hg)1.Maintain MAP at 90 mmHg (use inotropes if necessary)2.Maintain ICP 7-15mm Hg (N=<20mmHg) Head up posture Dexamethasone / mannitol / diuretics3. Maintain PaCO2 4.5 – 5 kPa

C. Reduce cerebral metabolism and O2 demand: Thiopentone Active Cooling