MEDICAL

1. Dr. Bruce Okari
ENT part 2
Supervisor: Dr. P. Mwika
Date: 06/12/2021
PHYSIOLOGICAL MONITORING
OF A SURGICAL PATIENT

2. Introduction
• Physiological response to stress is important in determining the
outcome
• monitoring of physiological response
allows determination of physiological reserve
allows assessment of baseline of effective treatment.

3. • physiologic monitoring of a surgical patient ranges from the routine
and intermittent measurement of the classical vital signs such as;
temperature
HR
 arterial BP
 RR
SPO2.

4. Types of surgical injuries
• Injury/ trauma
• acute blood loss
• shock
• hypoxia
• acidosis
• hypothermia
• altered microcirculatory blood flow
• altered coagulation and immune system
• pain

5. Physiological monitoring entails:
• Homeostasis of:
CVS
Respiratory system
nervous system
renal system
hematologic system
hepatic function
Scoring systems

6. CVS
• Pulse rate
• Blood pressure - Non invasive arterial BP monitoring
-Invasive BP monitoring;- intra arterial, CVC
• ECG
• Temperature

7. Pulse rate
• Pulse is a wave of blood created
by alternate expansion and
recoil of elastic arteries after
each contraction of the left
ventricle of the heart.
-Resting PR; 60-100 BPM

8. Bradycardia and tachycardia

9. Arterial blood pressure
• Affected by changes in the volume status of the patient, vasomotor
tone and cardiac output.
• If blood pressure is inadequate then tissue perfusion will be
inadequate .
• In critical illness autoregulatory mechanisms in vascular beds such as
the brain and kidney may become impaired and perfusion to these
organs will be pressure dependent.

10. Non invasive BP monitoring
• Manual and automated means use an inflatable sphygmomanometer
cuff to increase pressure around an extremity to detect the presence
or absence of arterial pulsations.
• The time-honored approach is the auscultation of the Korotkoff
sounds, which are heard over an artery distal to the cuff.
• Systolic pressure is defined as the pressure in the cuff when tapping
sounds are first audible. Diastolic pressure is the pressure in the cuff
when audible pulsations first disappear.

11. Invasive arterial BP
• Direct and continuous monitoring
of arterial pressure in critically ill
patient using fluid-filled tubing to
connect an intra-arterial catheter
to an external strain-gauge
transducer
• sites include the radial, femoral
and axillary artery
• Cannulation can be associated with
complications; thrombosis,
ischemia, infection, bleeding,
fistula, pseudoaneurysm

12. Invasive arterial BP monitoring indications
• Shock states
• Hypertensive crisis
• Extensive surgery in high risk patients
• Use of potent vasoactive or inotropic drugs
• High level of respiratory support (ventilator)
• High risk patients undergoing extensive surgery
• Controlled hypotensive anesthesia
• Any situation leading to rapid alteration in cardiac function

13. Central Venous Pressure (CVP)
• Useful but not very accurate in assessing volume status
• Indications;
 hypovolaemia following trauma
shock
burns
Sepsis
Normally CVP ranges between 6 and 12 mmHg

14. Common sites for CVP;
• External jugular vein,
• Internal jugular vein
• Subclavian vein
• Femoral vein
• Antecubital vein

15. CVP- Complications
• Pneumothorax
• Central line associated bloodstream infections
• Staphylococcus aureus and Staphylococcus
• epidermidis sepsis
• Air embolism
• Haemorrhage
• Nerve injury
• Arrhythmias

16. ECG
• ECG records the electrical
activity associated with cardiac
contraction by detecting
voltages on the body surface.
• Dysrhythmias can be detected
by continuously monitoring the
ECG tracing, and timely
intervention may prevent
serious complications

17. Temperature monitoring
• The purpose of temperature monitoring is to detect thermal
disturbances and maintain appropriate body temperature during
anesthesia.
• Core body temperature should be measured in most patients given
general anesthesia for more than 30 min.
• Core temperature monitoring is appropriate during most general
anesthetics both to facilitate detection of malignant
hyperthermia and to quantify hyperthermia and hypothermia

18. Respiratory system
• Assessing whether there is need to put patient on oxygen or
mechanical ventilation and in weaning off a ventilator
Respiratory rate
Pulse oximetry
ABG
Capnography

19. Pulse oximetry
• Non invasive measure of arterial
oxygen saturation of Hb and
pulse rate.
• Provides instant feedback on
oxygenation.
• Disadvantage: can’t distinguish
between carboxyhaemoglobin
and oxyhaemoglobin due to a
similar absorption spectrum.

20. Arterial blood gas analysis
• Assess adequacy of ventilation and
oxygenation
• Aids in diagnosing respiratory failure
and assessing severity of respiratory
failure
• Assesses changes in acid- base
homeostasis.
• Helps guide treatment plan
• Helps in management of ICU patients.
• Should be interpreted in relation to
the inspired oxygen tension (FIO2)
• COPD patients can tolerate abnormal
blood gas values.

21. Capnography
• Non invasive measurement of partial pressure
of CO2 in exhaled breath expressed as the
CO2 concetration over time.
• Relationship of CO2 concentration to time is
graphically represented by the CO2
waveform, or capnogram.
• Provides instant information on;
Ventilation
Perfusion
Metabolism.
Predictable relationship with arterial CO2
Monitoring is important in detecting
pulmonary emboli
Correlates with cardiac output and coronary
perfusion during resuscitation

23. Nervous system
• monitoring CNS function by Glasgow coma score and other assessments of
routine neurological status is an essential part of the management of the
critically ill patient.
• Includes monitoring:
intracranial pressure (ICP)
Transcranial near-infrared spectroscopy
Brain tissue oxygen tension
EEG and evoked potentials
Cerebral function monitoring (CFM)
Transcranial doppler U/S
Jugular venous oximetry

24. Intracranial pressure (ICP)
• The goal of ICP monitoring is to ensure that cerebral perfusion
pressure (CPP) is adequate to support perfusion of the brain. CPP is
equal to the difference between MAP and ICP: CPP = MAP – ICP.
• Normal ICP in adults; 5-15mm HG (7.5- 20 cm H2O)
Measures intraventricular pressure directly or indirectly.
Recommended in patients with TBI, GCS<8
Intracranial
pressure (ICP)

25. Increased ICP is seen in;
Head injury
SAH
Hepatic encephalopathy
Brain tumors or SOL
Encephalitis

26. ICP ct
• ICP above 20-25mmHg often amenable to therapeutic intervention
including;
Control of hypercapnia (using mechanical ventilation to maintain a
PaCO2 of 4kPa),
Mannitol
Slight head-up tilt
Sedation with an intravenous anaesthetic agent such as propofol or
thiopental

27. EEG
• Measures voltage fluctuations resulting from ionic current flows
within the neurons of the brain.
• Indications;
 Epilepsy
Coma
Encephalitis
Brain death

28. EEG utilization;
• Continuous EEG (CEEG) monitoring in the intensive care unit permits
ongoing evaluation of cerebral cortical activity. It is especially useful in
obtunded and comatose patients.
• CEEG also is useful for monitoring of therapy for status epilepticus
and detecting early changes associated with cerebral ischemia.
• An advance in EEG monitoring is the use of the bispectral index (BIS)
to titrate the level of sedative medications.
• The BIS also has been validated as a useful approach for monitoring
the level of sedation for ICU patients, using the revised Sedation-
Agitation Scale as a gold standard

29. Renal system
• Renal function monitoring, in critically-ill patients, allows detection of
changes in glomerular filtration rate (GFR) and promptly diagnose AKI,
via;
Urinalysis,
Urine output,
RFTs, and
serum creatinine level

30. Urinalysis and urine output
• Measurement of the specific gravity and osmolality of the urine is
used to differentiate between pre-renal and renal failure.
• Hourly urine output is a very useful guide to the adequacy of cardiac
output, splanchnic perfusion and renal function and a marker of
adequate hydration.
0.5-1 mL/kg/hr (30-40mls/hr) for adults
1 mL/kg/hr for children
 1-2 mL/kg/hr in toddlers < 2 years

31. GFR
• Creatinine clearance is the most reliable method for GFR assessment
Measurements over 24hrs, but 2hr clearance reasonably accurate.

32. Tubular Function Tests
• Primarily used in differential
diagnosis of oliguria
• Differentiate pre-renal cause
from intrinsic failure due to
tubular dysfunction
• Fractional excretion of sodium
most reliable lab test
• Value of <1 suggests pre-renal
• >2-3 compromised tubular
function

33. Hematological
• CBC;
WBC levels
Hb level
HCT levels/drop
Platelet levels
• Assessment of clotting function by measuring, PT, APTT, FDPs and D-
dimer.
• Main causes of clotting factor deficiencies; liver disease, vit K
deficiency, anti-coagulation drugs, DIC and massive blood transfusion.

34. Hepatic
 Wide range of functions including detoxification, protein synthesis
and production of biochemicals necessary for digestion
 Has a high functional reserve
Importance of monitoring LFTs to assess liver function
Importance of differentiating between hepatocellular damage (?
transaminases) obstructive picture (? alk phosph)

35. Hepatic Ct
• Albumin, clotting factors, anti-thrombin III and protein C all
synthesized in the liver
• Usually albumin not used in assessing acute liver function due to its
long half-life
• Clotting and prothrombin time are useful indicators of liver function
Factor
• VII useful in assessing severity of coagulopathy even where fresh
frozen plasma has been given (its half-life 4-8hrs)

36. Scoring systems
• Acute physiological and chronic
health evaluation (APACHE)
• Modified early warning score
(MEWS)
• qSOFA
• SOFA
• NEWS

37. MEWS

39. References
• Swartz’s Principles of Surgery 11th edition- Chapter 13
• https://pubs.asahq.org/anesthesiology/article/134/1/111/108291/Periope
rative-Temperature-Monitoring
• Guidelines for Perioperative Care in Elective Colorectal Surgery: Enhanced
Recovery After Surgery (ERAS) Society Recommendations: 2018
• https://jamanetwork.com/journals/jamasurgery/article-abstract/2595921
• https://pssjournal.biomedcentral.com/articles/10.1186/s13037-019-0213-
5
• https://pubmed.ncbi.nlm.nih.gov/20079469/
• https://www.sccm.org/Clinical-Resources/Guidelines/Guidelines/Surviving-
Sepsis-Guidelines-2021
• Google images.