ANESTHESIA: INTRAOPERATIVE MONITORING (based on T) Flashcards
Who ensures the surgical safety checklist is recited before surgery?
The nurse and the OR team, as mandated by the WHO and the DOH.
What is the purpose of creating a culture of safety in the operating room?
It prevents serious harm to the patient or the operating room team by identifying and stopping unsafe acts before harm occurs.
What is the primary benefit of using a surgical safety checklist?
It reduces the incidence of preventable surgical complications, such as wrong-site surgery, retained foreign objects, and administration of a medication allergy.
Who should be present in the room throughout the conduct of all general anesthetics?
Qualified anesthesia personnel.
What are the parameters that shall be continually evaluated during anesthesia?
Oxygenation, ventilation, circulation, and body temperature.
How is oxygenation monitored in a patient under anesthesia?
By measuring inspired gas in the patient’s breathing system with an oxygen analyzer and monitoring blood oxygenation using a pulse oximeter.
How is the adequacy of ventilation monitored in a patient under general anesthesia?
By qualitative clinical signs, chest excursion, breathing bag observation, auscultation, and continual monitoring of expired carbon dioxide.
What is the method for verifying correct placement of an endotracheal tube or laryngeal mask?
By clinical assessment and the identification of carbon dioxide in the expired gas.
How is ventilation monitored during regional anesthesia or local anesthesia without sedation?
By continual observation of qualitative clinical signs.
How is circulation monitored during anesthesia?
By continuously displaying ECG and determining arterial blood pressure and heart rate at least every five minutes.
What must be continually evaluated in a patient under general anesthesia regarding circulation?
Palpation of pulse, auscultation of heart sounds, intra-arterial pressure tracing, or ultrasound peripheral pulse monitoring.
What is the meaning of ‘continual’ in anesthesia monitoring?
Repeated regularly and frequently in steady rapid succession.
What is the difference between ‘continual’ and ‘continuous’ monitoring?
‘Continual’ refers to repeated monitoring, while ‘continuous’ refers to uninterrupted monitoring.
Which parameters does the anesthesia monitor track?
Blood pressure, pulse rate, and SpO2.
What is the importance of the surgical position in anesthesia?
It helps to reach the desired dermatome level and prevents nerve injury by using padding.
What medical gases are commonly used in operating rooms?
Oxygen, nitrous oxide, air, and nitrogen.
What are the consequences of a malfunction in the medical gas system?
It can endanger patients, particularly if oxygen systems are misconfigured or malfunctioning.
What system prevents incorrect connections between anesthesia machines and gas cylinders?
The Pin Index Safety System.
How does the Pin Index Safety System work?
Each gas cylinder has two holes that mate with corresponding pins in the anesthesia machine’s yoke, preventing incorrect gas connections.
What safety feature is present in oxygen E-cylinders?
Oxygen E-cylinders have a ‘plug’ made from Wood’s metal to prevent incorrect connections.
What is the primary method for delivering medical gases to the operating room?
Through a network of pipes, sized to prevent a pressure drop of more than 5 psig.
How are anesthesia machines connected to the medical gas supply system?
By color-coded hoses using quick-coupler mechanisms and a non-interchangeable diameter index safety system fitting.
How is the gas supply from cylinders typically delivered in anesthesia machines?
Via the Pin Index Safety System.
How are the medical gases delivered to the patient through the breathing system?
Through breathing circuits that link the patient to the anesthesia machine.
What is insufflation in anesthesia?
The technique of blowing anesthetic gases across a patient’s face, often used in pediatric anesthesia to avoid face mask placement.
What components make up the circle system in anesthesia?
CO2 absorber, fresh gas inlet, inspiratory and expiratory unidirectional valves, Y-connector, APL valve, and reservoir.
What is the role of the APL valve in the circle system?
It is an adjustable pressure-limiting valve that can be adjusted as needed.
What does the CO2 absorber in the circle system contain?
Soda lime or calcium hydroxide.
How is the breathing system related to the anesthesia machine?
It connects the patient to the anesthesia machine, facilitating the delivery of anesthetic gases.
How does the anesthesia machine receive medical gases?
The anesthesia machine receives medical gases either from the pipeline or the cylinder.
What does the anesthesia machine control?
The anesthesia machine controls the flow of oxygen.
What is the purpose of the pressure reduction in the anesthesia machine?
The anesthesia machine reduces the pressure of desired gases to a safe level.
Which volatile anesthetics are vaporized by the anesthesia machine?
The anesthesia machine vaporizes volatile anesthetics such as sevoflurane, haloflurane, and desflurane.
How does the anesthesia machine deliver gases to the patient?
The anesthesia machine delivers gases to a breathing circuit that is connected to the patient’s airway.
Can the anesthesia machine’s ventilator be excluded during certain procedures?
Yes, the ventilator can be excluded with a switch during spontaneous or manual (bag) ventilation.
How does oxygen flow in the anesthesia machine?
Oxygen supply can pass directly to its flow control valve.
What is the safety feature related to the flow of nitrous oxide and oxygen?
Nitrous oxide, air, and other gases must pass through safety devices before reaching their respective flow control valves, preventing hypoxic mixtures in case of oxygen supply failure.
What is the linkage between nitrous oxide and oxygen in the anesthesia machine?
The oxygen flow is linked to the nitrous oxide gas flow to ensure a minimum oxygen concentration of 25%.
What is the difference between the high-pressure and low-pressure circuits in the anesthesia machine?
Gas lines proximal to flow valves are part of the high-pressure circuit, while those between the flow valves and the common gas outlet are part of the low-pressure circuit.
Describe the flow meters in the anesthesia machine.
Constant pressure variable-orifice flowmeters (Thorpe type) are used in the anesthesia machine.
What are vaporizers used for in anesthesia machines?
Vaporizers are used to vaporize volatile anesthetics and deliver them to the patient.
What does the variable bypass vaporizer (Drager Vaporizer) do?
It mixes fresh gas with anesthetic agent and adjusts the concentration by controlling the flow through the vaporizing chamber.
What is the safety feature of anesthesia machines related to vaporizers?
An anesthesia machine should have an interlocking or exclusion device to prevent the concurrent use of more than one vaporizer.
What is the main function of ventilators in anesthesia machines?
Ventilators generate gas flow by creating a pressure gradient between the proximal airway and the alveoli.
How does the bellows system work in a ventilator?
In a double-circuit system, the bellows assembly delivers tidal volume and draws attention to circuit disconnections when collapsed.
What is an auxiliary O2 flow meter used for?
The auxiliary O2 flow meter is used during regional or local anesthesia to deliver O2 via nasal cannula.
What causes arterial blood pressure (ABP)?
ABP is caused by the rhythmic contraction of the left ventricle, ejecting blood into the arterial tree.
What is the formula to estimate mean arterial pressure (MAP)?
MAP can be estimated by the formula: MAP = (SBP + 2(DBP)) / 3.
What are methods of non-invasive blood pressure determination?
Non-invasive methods include palpation, Doppler, auscultation, oscillometry, plethysmography, and volume clamp.
Why is the radial artery commonly used for arterial cannulation?
The radial artery is commonly used due to its superficial location and substantial collateral flow.
What is the main advantage of invasive blood pressure monitoring?
Invasive blood pressure monitoring provides continuous beat-to-beat measurements of blood pressure.
Why might blood pressure readings vary in extremities with vascular abnormalities?
In patients with severe peripheral vascular disease, blood pressure readings may differ among extremities, and the greater value should be used.
How does the ECG help during anesthesia monitoring?
The ECG provides audible beeps for QRS complexes, detecting rate and rhythm changes when the anesthesiologist’s visual attention is directed elsewhere.
What is the importance of lead placement for ischemia detection in ECG?
Rearranging lead placement can help detect anterior and lateral ischemia, especially when the left arm lead is placed at the V5 position.
What are the advantages and limitations of TTE and TEE?
TTE is non-invasive but challenging to obtain the right views; TEE is ideal in the operating room with limited chest access.
What were precordial and esophageal stethoscopes used for prior to gas exchange monitors?
They were used to ensure lung ventilation, monitor for circuit disconnections, and auscultate heart tones.
What are some disadvantages of the esophageal stethoscope?
It can cause mucosal irritation and bleeding and is limited to intubated patients.
What are the components of a precordial stethoscope?
It includes a Wenger chest piece and extension tubing connecting to the anesthesia provider’s earpiece.
What is the principle behind pulse oximetry?
Pulse oximetry combines oximetry and plethysmography to measure oxygen saturation in arterial blood using light absorption.
What is Lambert-Beer’s Law in pulse oximetry?
It states that oxygenated and reduced hemoglobin absorb different amounts of red and infrared light, allowing for SpO2 calculation.
What causes pulse oximetry artifacts?
Artifacts can arise from excessive ambient light, motion, methylene blue dye, venous pulsations, low perfusion, sensor misplacement, optical shunting, carbon monoxide poisoning, and methemoglobinemia.
What is the purpose of the Lifebox Foundation?
It facilitates access to pulse oximeters in low- and middle-income countries where they are not available.
What does capnography rely on to detect CO2?
Capnography relies on the absorption of infrared light by CO2, governed by the Beer-Lambert law.
What is a key limitation of capnography?
Capnography does not reliably detect mainstem bronchial intubation.
What is a normal capnography waveform and its phases?
Phase I: Dead space, Phase II: Mixture of dead space and alveolar gas, Phase III: Alveolar gas plateau.
What is the significance of BIS (Bispectral Index)?
BIS monitors EEG components to indicate the level of anesthesia, with 65-85 for sedation and 40-65 for general anesthesia.
What are some consequences of hypothermia during anesthesia?
Hypothermia can lead to delayed drug metabolism, hyperglycemia, vasoconstriction, impaired coagulation, and increased surgical site infections.
What are the effects of hyperthermia in patients undergoing anesthesia?
Hyperthermia can lead to tachycardia, vasodilation, and neurological injury.
How are thermistors and thermocouples used in temperature monitoring?
Thermistors change resistance with temperature, while thermocouples generate a voltage difference when metals are at different temperatures.
What is the most reliable method for monitoring urinary output during surgery?
Urinary bladder catheterization is the most reliable method for monitoring urinary output.
What are the indications for urinary bladder catheterization during surgery?
Cardiac surgery, vascular surgery, craniotomy, major abdominal surgery, and surgeries with expected large fluid shifts.
Why must neuromuscular function be monitored in patients receiving neuromuscular blocking agents?
To detect the onset of paralysis and ensure adequate block during anesthesia.
What is the function of a peripheral nerve stimulator?
It delivers current to peripheral motor nerves to observe muscle responses and monitor neuromuscular blocking agents.
What is the significance of adductor pollicis recovery in peripheral nerve stimulation?
Recovery of adductor pollicis function does not parallel recovery of airway muscles.
What are some clinical indicators of adequate recovery from neuromuscular blockade?
Sustained head lift, inspiratory pressure of -25 cm H2O, and forceful hand grip.
What are the potential complications of neuraxial anesthesia?
“The complications of neuraxial anesthesia include excessive physiological effects from the drug. injury from needle or catheter placement and systemic local anesthetic toxicity.”
What are the three layers of the meninges?
“The three layers of the meninges are the pia mater. arachnoid mater and dura mater.”
What is the subarachnoid space?
“The subarachnoid space is the space between the pia mater and the arachnoid mater. containing cerebrospinal fluid (CSF).”
Where does the dural sac typically end in adults?
“The dural sac typically ends at S2 in adults.”
What are common complications related to neuraxial anesthesia?
“Complications can include urinary retention. high block. cardiac arrest. anterior spinal artery syndrome and hornet syndrome.”
What is systemic local anesthetic toxicity?
“Systemic local anesthetic toxicity occurs when excessive amounts of local anesthetic are absorbed
What is cauda equina syndrome?
“Cauda equina syndrome is a complication that involves nerve root damage and can cause lower back pain. weakness and sensory loss.”
What are signs and symptoms of high neural blockade?
“Signs and symptoms include difficulty breathing. numbness or weakness in the upper extremities. nausea and hypotension.”
How should high neural blockade be treated?
“Treatment includes maintaining adequate oxygenation. ventilation. vasopressors for hypotension. atropine for bradycardia and possibly intubation.”
What can cause cardiac arrest during spinal anesthesia?
“Cardiac arrest during spinal anesthesia is often caused by hypotension and bradycardia which should be treated promptly.”
What causes urinary retention in neuraxial anesthesia?
“Urinary retention is caused by the blockade of S2-S4 root fibers which decrease urinary bladder tone and inhibit the voiding reflex.”
What are common causes of inadequate anesthesia?
“Inadequate anesthesia may occur due to movement of the needle. incomplete entry into the subarachnoid space subdural injection or intravascular injection.”
What is Local Anesthetic Systemic Toxicity (LAST)?
“LAST is caused by excessive absorption of local anesthetic
What should be done for intravascular injection during neuraxial anesthesia?
“Intravascular injection can lead to local anesthetic systemic toxicity (LAST). requiring immediate treatment with lipid emulsion and epinephrine.”
What is total spinal anesthesia?
“Total spinal anesthesia occurs when spinal anesthesia extends into the cervical area causing respiratory and cardiovascular instability.”
What is subdural injection?
“Subdural injection is when local anesthetic is mistakenly injected into the subdural space leading to a delayed onset of high spinal symptoms.”
What is Postdural Puncture Headache (PDPH)?
“PDPH is a headache that occurs following a dural puncture often exacerbated by sitting or standing and relieved by lying flat.”
What is the treatment for Postdural Puncture Headache?
“The treatment for severe PDPH includes an epidural blood patch
What causes neurological injury during neuraxial anesthesia?
“Neurological injury can occur from epidural hematoma. abscess or direct nerve root/spinal cord damage.”
What is a risk factor for spinal and epidural hematomas?
“Abnormal coagulation such as in patients on anticoagulants or with a history of vascular disease. increases the risk of spinal and epidural hematomas.”
What is the most common cause of epidural abscess?
“Epidural abscesses are most commonly caused by contamination from microorganisms like Staphylococcus aureus or S. epidermidis.”
What is transient neurological symptoms (TNS)?
“TNS refers to transient radicular irritation causing back pain radiating to the legs often associated with hyperbaric lidocaine.”
What are common nerves injured in perioperative peripheral nerve injuries?
“Commonly injured nerves include the ulnar nerve. brachial plexus and lumbosacral root.”
What is the classification for nerve injury in Seddon’s system?
“Seddon’s classification includes neurapraxia (mild). axonotmesis (moderate) and neurotmesis (severe).”
What is Sunderland’s classification of nerve injury?
“Sunderland’s classification includes five types ranging from mild (type 1) to complete nerve severance (type 4).”
What are some predisposing factors for perioperative peripheral nerve injury?
“Predisposing factors include thin or obese body habitus.old age.vascular disease.diabetes and male gender.”
What are the risk factors for perioperative eye injuries?
“Risk factors for eye injuries include prolonged positioning. external compression and failure to protect the eyes during surgery.”
What is the benefit of a stepwise approach to perioperative cardiac assessment?
It helps clinicians determine when surgery should proceed or if further evaluation is needed.
What is the general principle for cardiovascular screening and treatment in noncardiac surgery?
It should follow the same indications as for nonsurgical patients, avoiding over-screening and overtreatment.
When should stress testing be performed in patients undergoing noncardiac surgery?
Only in patients where testing would be appropriate regardless of planned surgery, especially avoiding unnecessary testing in low-risk patients.
What is emphasized for managing patients with complex anatomy or unstable cardiovascular disease?
Team-based care.
Why should sodium-glucose cotransporter 2 (SGLT2) inhibitors be discontinued 3-4 days before surgery?
To minimize the risk of perioperative ketoacidosis.
What is myocardial injury after noncardiac surgery (MINS) and why is it important?
It is a newly identified disease process with real consequences for affected patients and should not be ignored.
What type of kidney injury is caused by NSAIDs, ACE inhibitors, radiocontrast agents, amphotericin B, cyclosporine, and tacrolimus?
Decreased renal perfusion.
What type of kidney injury is caused by aminoglycosides, radiocontrast agents, amphotericin B, methotrexate, cisplatin, and other nephrotoxic agents?
Direct tubular injury.
What type of kidney injury is caused by radiocontrast agents, methotrexate, acyclovir, sulfonamides, ethylene glycol, uric acid, cocaine, and lovastatin?
Intratubular obstruction.
What type of kidney injury is caused by penicillins, cephalosporins, allopurinol, NSAIDs, sulfonamides, diuretics, rifampin, ciprofloxacin, cimetidine, PPIs, tetracycline, and phenytoin?
Immunological-inflammatory injury.
