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Perioperative Events. CP4004 2010-2011 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
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Perioperative Events CP4004 2010-2011 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
Fluid Rescucitation • ADULT 1-2I of rapid crystalloid infusion • (PAEDIATRIC 20ml/kg) • Then assess response
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 losses Burns Corticosteroid withdrawal Cardiac failure TURP Excess dextrose infusion SIADH: 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%dextrose • Calcium Gluconate 10mls 0f 10% over 2 min ß agonists • K binding resin • Dialysis
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 >12x109/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 lessintubation Scottish Intercollegiate Guidelines Network SIGN Guideline 46 Early Management of Head Injury http://www.sign.ac.uk/guidelines/fulltext/46/index.html
Principles of management Maintain good oxygenationIncreased 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 perfusion CPP=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 / diuretics 3. Maintain PaCO2 4.5 – 5 kPa C. Reduce cerebral metabolism and O2 demand: Thiopentone Active Cooling