Resus, airway and anaesthetics Flashcards
With relevance to RSI, list three (3) physiological effects of obesity on the respiratory system and two (2) physiological effects on other organ systems.
Respiratory Effects
- High incidence of resting hypoxaemia
- High incidence of resting hypercarbia
- Increased oxygen consumption
- Increased carbon dioxide production
- Inefficient respiratory muscles
- Increased airway resistance
- Reduced TLC
- Reduced VC
- Decreased expiratory reserve volume (from collapse of the small airways)
- Reduced FRC (declines exponentially as BMI increases)
- Increased work of breathing especially supine
Non-Respiratory effects:
- Increased intra-abdominal pressure
- Increased incidence of hiatus hernia
- Increased gastro-oesophageal reflux
- Increased gastric volume
- Higher volume of distribution
- Increased carbon dioxide production
What special consideration need to be made for intubating a pregnant woman
AIRWAY
- Airway edema and friability so cannot have repeated intubation attempts and poor Mallampati. This is especially evident during labour and in pts with preeclampsia
- Hyperemia and nasal polyps so increased risk of bleeding with nasal adjuncts and needs small er ETT, size 7
- Breast tissue obstructing laryngoscopy blade and so need to use short handle
RESPIRATORY
- Increased metabolic demand and decreased FRC so has shorter apnea times, needs passive oxygenation with NP at 15L
- Harder BMV due to increased intraabdominal pressure and so needs head up 30 degrees
GASTROINTESTINAL
- Lower esophageal sphincter incompetence with GORD
- distorted gastric anatomy due to enlarged uterus
- Delayed gastric emptying in labour
Therefore increased risk of aspiration and pt should not be bagged during apneic phase when able to avoid. Also need cricoid pressure to compress esophagus
POSITIONING
- Needs 15 degrees left lateral tilt to prevent aortocaval compression
What special considerations need to be made for intubating a geriatric patient
4 principles of airway management in a geriatric pt are:
- Increased likelihood of requiring intubation during acute illness
- Increased difficulty performing BMV and intubation
- Increased difficulty maintaining oxygenation and preventing complication due to reduced cardiopulmonary reserve
- Need for adjustment in drug selection and dosing during RSI
AIRWAY
- Poor mask seal during BMV from missing teeth
- Difficult maintaining airway due to loss of upper airway tone
- Reduced neck mobility from cervical spine arthritis so more difficult laryngoscopy
RESPIRATORY
- High rates of comorbid intrinsic lung disease so more difficulty preoxygenating and may require BiPAP
- Impaired gas exchange and reduced PaO2 due to impaired lung parenchyma causes decreased apnea time
- More susceptible to permanent cardiac or neurological damage from brief periods of apnea, so sats need to maintained >90%
- Decreased chest wall compliance so more difficulty ventilating through BMV and LMA
- Decreased lung elasticity and increased V/Q mismatch
- Reduced cough and mucociliary clearance increase risk of aspiration
CARDIOVASCULAR
- Diminished cardiopulmonary reserve leading to heightened sensitivity to negative inotropy and vasodilation from induction agents, should have 30% dose reduction, especially if showing signs of shock, and adequate fluid resus +/- inotropes
DRUGS
- More likely to have comorbid advanced coronary artery disease or tachydysrhythmia and so ketamine should be avoided as can aggravate tachycardia and increase myocardial demand.
- Risk of hyperK is denervating stroke between 3 days and 6 months ago
ETHICAL
- Should have discussions with pts and their family to determine appropriate limits of care, ideally prior to any anticipated deterioration
How do you approach intubation in an UPGI haemorrhage
- Ensure appropriate PPE with gowns, gloves, goggles and masks
- Blood transfusions/MTP +/- norad, should convert 20G to RIC line
- Head up positioning 45degrees
- Consider large bore NG pretreatment with 20mg IV metoclopramide to decrease aspiration risk however this should not delay intubation
- Double suction setup with 2 assistants
- Ketamine 1-2mg/kg with Rocuronium 1.2mg/kg
- Avoid NIV or BVM for preoxygenation and apneic oxygenation due to risk of gastric insufflation if possible. If BVM needed, then should be gentle technique with <15cmH2O PEEP
- Video laryngoscopy with SALAD technique
- If vomits release cricoid pressure and place in Trendelenburg position
What is the SALAD technique and how do you perform it?
Suction assisted Laryngoscopy Airway Decontamination is a method of suctioning during itbation to prevent aspiration during intubation
1) Suction of oral cavity using Yankauer sucker followed by laryngoscopy blade insertion avoiding submerging the optics module in vomitus
2) Yankauer sucker to act as tongue depressor allowing laryngoscopy blade into correct position
3) Suction of hypopharynx and then insertion of the Yankauer sucker into the esophagus for continuous drainage
4) Reposition Yankauer sucker to the L side of mouth. Assistant to hold the Yankauer sucker in place
5) May need slight leftward rotation to the laryngoscopy blade 30 degrees if larynx not visible, otherwise intubate, inflate cuff and suction of tracheal tube prior to ventilation
Outline five (5) strategies that can be implemented to improve the safety of endotracheal intubations for all patients in the emergency department.
- Standardized pre-RSI checklist
- Standardized difficult airway algorithm instituted
- RSI performed by only by adequately experienced operators
- Standardized equipment availability including video-laryngoscopy equipment.
- Mandated the use of nasal prong apnoeic (diffusion oxygenation)
- Mandated use of a bougie or stylet for all intubation attempts
- Regular training of staff
- Provision of part task training and cadaveric workshops
After a successful intubation, list three (3) interventions to decrease the risk of a patient developing a ventilator associated pneumonia
- New circuit for a new patient
- Semi recumbent position 30-45°
- Maintenance of endotracheal cuff pressure of about 20 mmHg
- Subglottic suctioning
- Mouth cares
- Avoidance of flushing of condensate into lower airway
The Australian Resuscitation Council state that CPR is likely to be futile beyond twenty minutes when four criteria have been met. List these (4 marks)
- No reversible causes
- Non shockable rhythm
- No ROSC or age >80
- Non witnessed arrest
- Persistently low ETCO2 values (<10 mm Hg) during CPR in intubated patients after 20 mins has essentially zero survival (for intubated pts)
- No cardiac activity on US
State five clinical circumstances where prolonged resuscitation attempts may be warranted
- Toxicological cause (full neuro recover after 4hrs of CPR possible)
- Post thrombolysis (2hrs post thrombolysis)
- hypothermia (core temp at least 32 before ceasing)
- Asthma (correct for dynamic hyperinflation)
- Pregnancy prior to resuscitative caesarean section
- Persistent VF in young people until reversible and therapeutic options exhausted
When would you decide to intubate
- Failure to maintain own airway (GCS<8, aspiration risks, requiring manoeuvres and tolerating OPA to maintain airway)
- Hypoxic resp failure
- Hypercapnic resp failure
- Anticipating clinical course (airway burns, penetrating neck trauma or significant trauma, ceratin overdoses)
How to assess an anatomically difficult airway in context of BMV
MOANS
M - mask seal (beards, Leforte fractures, burns)
O - obesity/obstruction
A - Age >55
N - No teeth
S - Stiff lungs (poor lung compliance)
How to assess an anatomically difficult airway in context of laryngoscopy
LEMON
L (look) - look externally using clinician gestalt (can they bite their upper lip)
E (evaluate) - 3 mouth opening 3 submental space and 2 thyromental space
M (mallampati) - Mallampati measures relative size of tongue compared to roof of palate as well as depth of mouth
O - obesity/obstruction
N - Neck mobility (C spine injuries, geriatrics, RA and DS have increased risk of atlantoaxial instability and dislocations)
How to assess an anatomically difficult airway in context of supraglottic devices
RODS
R - Restriction of mouth opening
O - Obstruction/obesity
D - Distorted anatomy
S - Stiffness
How to assess an anatomically difficult airway in context of cricothyroidotomy
SMART
S - Surgery
M - masses (abscess, hematoma)
A - Access/anatomy (obesity, oedema)
R - Radiation
T - tumours
What are the physiologically difficult airways and why are they important
Greatest predictor of cardiovascular collapse with RSI medications and transition to PPV
- Hypotension (SBP<100 and elevated shock index >0.8)
- Hypoxia (Sats <93%)
- Acidosis/alkalosis
- Respiratory conditions underlying (severe asthma, COPD, pulmonary HTN, R heart failure)
- Medications/medical conditions (elevated ICP, acute MI, tachydysrhythmias, obesity, pregnancy, age)
- Sepsis
Confirmation of ETT placement
Continuous waveform capnography (preferred)
or
Digital (2nd) or Colorimetric (3rd) ETCO2 as less reliable alternatives
(yellow = yes but needs at least 6 breaths)
- impaired ETCo2 in complete obstruction, asthma and cardiac arrest
Using bronchoscope to directly visualise airways
Ultrasound
Esophageal detector devices
Direct visualization of tube going through chords
Palpation during intubation
Aspiration technique with cuff deflated
Clinical bilateral chest rise
Auscultation bilaterally in each axilla
Misting of the ETT
What are the criteria on Waveform capnography to confirm tracheal intubation?
- Wave rises during expiration and falls during inspiration
- Peak amplitude is consistent and increasing over 7 breaths
- Peak amplitude is >7.5mmHg
Gastric CO2 will give capnography reading for up to 5 breaths, with ETCO2<7 and amplitude inconsistent and not rising.
In cardiac arrest ETCO2 normally still >15 however may drop near or below 7.5 after prolonged CPR. Will still have normal rise and fall
What is the approach to intubation after decision to intubate has been made
Is this a crash intubation
If not is this a difficult intubation
If not then proceed to RSI
Describe a difficult airway and the algorithm
A difficult airway is determined by the pre intubation airway assessment
If it is determined the pt has a difficult airway then RSI with double setup can be initiated ONLY if the operator is forced to act (pts current or expected deterioration) or intubation is likely to be successful AND oxygenation via BVM or supraglottic device is possible
Otherwise proceed with awake intubation. If pt unable to tolerate awake intubation or not successful not then attempt with flexible endoscopy, rigid bronchoscopy, intubating laryngeal mask, blind nasotracheal intubation or cricothyrotomy
To connect to BVM use 3mL Luer lock with plunger removed and the connector from a 7.5 ETT or 3.0 ETT connector attached directly to the catheter
To
Describe a failed airway and the algorithm.
If in ‘CICO’ (can not intubate and can not oxygenate) situation or 3 failed attempts at laryngoscopy the this is a failed airway
With CICO, proceed with a surgical airway
If the pt can be oxygenated (via BVM or SGD) but unable to be intubated via direct or videolaryngoscopy, then alternative methods such as a fibreoptic or intubating supraglottic device may be attempted when able. Otherwise to maintain oxygenation with SGD or proceed with surgical airway
How do you plan for and perform an RSI
The 7 Ps is helpful mnemonic to outline key steps
Preparation
Preoxygenation
Pretreatment
Paralysis with induction
Positioning
Placement with proof
Postintubation management
What are the basic steps in preparing for and RSI
Assessing for potentially difficult airway
Developing airway management plan including back up strategy
Assembling necessary personal, equipment and medications
Often covered in preintubation check lists
STOP MAID
- Suction
- Tools for intubation
- Oxygen
- Positioning
- Monitors
- Assistant/assessment/adjuncts
- IV acess x2
- Drugs
What are the goals and methods behind preoxygenation
Replace nitrogen with O2 in the gas exchanging portion of the lungs, significantly increasing safe apneic time. Needs at least 8 TV breaths or ideally 3 minutes before induction and continued during with apneic oxygenation via NP running at 15L
Time to desat to below 90% with apnea after proper preoxygenation
Healthy 70-kg male: 6 to 8 minutes
Young children (10 kg): <4 minutes
Adults with chronic illness or obesity: <3 minutes
Patient at near full-term pregnancy: <3 minutes
Inadequate spontaneous ventilation should have BVM with reservoir bag 15L O2 and gentle bagging synchronized with pts breathing
Adequate spontaneous ventilation with cooperate pt can have either HFNP or NIV with 100% O2. If available flush flow O2 via NRB can be used as well
Adequate spontaneous ventilation with a confused or uncooperative pt needs sedation with ketamine 0.5-1mg/kg IV or 3-5mg/kg IM with aliquots of 0.5mg/kg titrated to effect (disassosciation) with HFNP, NIV or NRB (THIS IS DELAYED SEQUENCE INTUBATION)
Causes of peri RSI hypoxia, clinical finding, intervention and prevention
DOPES
D - Displacement of endotracheal tube
Low PIP, decreased breath sounds, gastric breath sounds
Prevented with waveform capnography
Needs reintubation
O - Obstruction of ETT
High PIP, increased secretions, high resistance BMV
Prevented and managed with suctioning, bite block and ensuring tube not kinked
P - Pt factors (PTx, PE, APO, bronchspasm)
High PIP, High resistance to BMV, clinical findings such as crackles, wheeze or subcut emphysema
Management depends on cause
E - Equipment
Pt rapidly improves when switched to bagging if ventilator problem
ETT cuff leak suggested from low PIP and low pilot balloon pressures
Needs EET exchanged and prevented by checking ETT prior to intubation
S - Stacked breaths
Who qualifies for extubation in the ED
Improvement from underlying pathology causing intubation (toxidrome or head injury in intoxicated pts with normal CT)
A - Easy intubation (high POGO or Cormack-Lehane score 1/2)
B - Passed spontaneous breathing trial on minimal ventilator setting
(Sats >95%, PaO2>60 on FiO2<40% on PEEP</= 5 with 6<RR<30)
C - No ongoing hemodynamic compromise HR<100 and SBP>100
D - Passed awakening trial with pt rousable, able to follow commands and strong enough to lift head off pillow and raise arms in air for 15 seconds
Also palliated pts can be extubated in ED without meeting above criteria
How do you perform a resuscitative hysterotomy
Duration should not exceed 5 minutes and preparation should begin at the start of CPR to ensure ready within 4 minutes of the maternal arrest
Have neonatal resus team ready
Continue CPR and ventilation throughout
1) Incise from pubic symphysis to at least umbilicus (ideally fundal height) with a large scalpel along linea nigra into peritoneal cavity. Layers: skin, subcutaneous tissue, fascia between the rectus muscles, peritoneum.
2) Retract abdominal wall laterally
3) Reflect bladder inferiorly and empty by aspiration
4) Make a small incision (~5cm) vertically into the inferior presenting part of the uterus until amniotic fluid comes or through endometrium
5) Insert 2 fingers and lift up uterus from fetus
6) Extend uterine incision up to fundus with safety scissors curved away from fetus - if placenta in the way cut through it
7) Deliver the fetus. May need to disengage the presenting part from the pelvis.
8) Clamp the cord twice and cut between clamps
9) Give the neonate to the neonatal resuscitation team
10) Deliver the placenta
11) Swab the endometrial cavity to ensure no residual products of conception
12) Pack the uterus and abdomen +/- clamp bleeding vessels and suture uterine incision
13) Give synthetic oxytocin 5 units IV
Continue maternal resuscitation
If ROSC: watch for bleeding, consider further oxytocic drugs, TXA, antibiotic prophylaxis
Resuscitate neonate
