General considerations (dyspneic non infective patients)
Self Protection
The generic dyspneic patients do not pose any particular self protection issues above the general precautions
Clinical needs
Non infected dyspneic patient need moderately high FiO2 but considerately high oxygen flow rates.
The available systems we have in this moment (at least on my operative setting) to deliver normally pressured O2 are:
Nasal cannula
Maximum gas flow 15 l/m
FiO2 variable between 25-45%
Simple face mask
Maximum gas flow 15 l/m
FiO2 variable between 40-60% at the mask level
Nonrebreather face mask (reservoir)
Maximum gas flow 15 l/m
FiO2 more 80-100%
Venturi mask
Gas flow between 40 to over 80 l/m
FiO2 titratable between 24% and 60%
To satisfy the increased minute ventilation of the highly dyspneic patient Venturi mask is the best device (high flow rate) and permits at the same time to tritrate the FiO2 based on the patients need avoiding indiscriminate hyperoxygenation.
Particular considerations in dyspneic potentially infective COVID-19 patients
Disclaimer
The following considerations derived from our initial experience on the field in suspect or confirmed COVID-19 with respiratory symptoms at their presentation or in the initial phases. Those are the majority of the patients we observed till the day this post was written.
The following considerations are not intended for all the severe hypoxic patients who definitively need early intubation and positive pressure ventilation.
Clinical needs
Those are dyspneic hypoxic patients who needs moderately high FiO2 and request more gas flow rates to satisfy increased minute ventilation.
So from an exclusively clinical point of view the best way to deliver oxygen it would be a Venturi mask.
Self Protection
In the actual situation in Italy the epidemiological geographical criteria is no more reliable to identify COVID-19 patients so any prehospital healthcare professional providing direct care to a dyspneic patient needs to be protected al least with:
Eye protection or Facial shield
Medical mask
Disposable gown
Disposable gloves
At the same time good practice is to reduce at minimum the number of direct caring providers, to maintain, if possible, a security distance > 1 mt, to invite any patient to wear, if tolerated, a surgical mask, and a pair of disposable gloves to minimise the risk of infection.
When providing direct care of dyspneic patients who needs O2 therapy the level of risk for droplet diffusion is generally increased cause of the presence of the gas flow.
All the available systems for oxygen delivery we mentioned above are open and allow a free exaltation of the patient in the surrounding area and potentially exposes all the healthcare caregivers to an increased risk of contamination cause of the augmented droplet dispersion and to a lack of protection.
Considerations
So when dealing with O2 therapy in the potentially infected patients we need to consider the relationship between risk of contamination and clinical efficacy of any device.
Nasal Cannula
Oxygenation –—+
Protection ++++
Nasal Cannula is the only device that permits the patient to wear a surgical mask on nose and mouth, decreasing droplet diffusion and protecting the healthcare team and at the same time maintains a certain clinical efficacy..
So my first approach is Nasal Cannula underneath a medical mask.
Utilising a different device than nasal cannula plus medical mask on the patient mouth and nose (simple, non rebreather or Venturi face mask) to deliver oxygen therapy all healthcare professionals need to be aware that the risk infection increases and the patient has no barriers and so they have to consider improving his own self protection level (N95, FPP2 mask at least)
Simple/Non rebreather Facial Mask
Oxygenation —++
Protection ++–
When you can’t reach a clinical acceptable SpO2 with nasal cannula we need to downgrade on our first goal (protection) to achieve a better clinical outcome.
Simple facial masks maintain a moderate protection form droplet spreading with a more clinical efficacy respect th the nasal cannula.
Nonrebreather facial mask either moderately protects against droplet diffusion with an improvement in FiO2 above simple face mask but the nonrebreather bag is a potential expirate gas reservoir potentially increasing the risk of spreading.
Venturi mask
Oxygenation -++++
Protection —-+
High flow titratable FiO2 in an open system mask can satisfy all minute ventilation needing guaranteeing Oxygenation at a cost of a great risk of spreading. My last choice in the scale of conventional Oxygen therapy.
References:
DSC Hui, MTV Chan, B Chow. Aerosol dispersion during various respiratory therapies: a risk assessment model of nosocomial infection to health care workers. Hong Kong Med J 2014;20(Suppl 4):S9-13
M. P. Wan , C. Y. H. Chao , Y. D. Ng , G. N. Sze To & W. C. Yu (2007) Dispersion of Expiratory Droplets in a General Hospital Ward with Ceiling Mixing Type Mechanical Ventilation System, Aerosol Science and Technology, 41:3, 244-258, DOI: 10.1080/02786820601146985
Shu-An Lee, Dong-Chir Hwang, He-Yi Li, Chieh-Fu Tsai, Chun-Wan Chen,and Jen-Kun Chen. Particle Size-Selective Assessment of Protection of European Standard FFP Respirators and Surgical Masks against Particles-Tested with Human Subjects. Journal of Healthcare Engineering. Volume 2016, Article ID 8572493, 12 pages
Thanks for reviewing and suggesting to: Scott Weingart, Jim DuCanto, Velia Marta Antonini, Giacomo Magagnotti, Andrea Paoliand all the other colleagues and friends who supported this post
If you are interested on a daily update about the best emergency medicine literature follow me on Facebook, Twitter or give your like to MEDEST Facebook page.
Pathophysiological bases in experimental swine models
In a swine model following primary cardiac arrest the respiration continues at least for 1 minute. and after that Gasping starts lasting for another minute.
In a swine model following primary cardiac arrest the blood shifts from high pressure compartment (arteries) to low pressure compartment (veins).
In a swine model the PaO2 following primary cardiac untreated VF arrests PaO2 results 70 mmHg after 9 min with a saturation of 93% and decrease at 44 mmHg with a saturation of 61% after 14 min of CPR. In this period airway management with possible interruption of chest compressions and starting positive pressure ventilation (with decreased return to the thorax end depression of cardiac output) is not mandatory due to the low cost/beneficial ratio and the potential detrimental effect.
Chest compressions
Chest compressione only CPR is associated with worst outcome in childrenunder 8 yers. Always perform chest compression/ventilation (ratio 15:2) in children <8 years of age (only exception if the cardiac arrest is due to primitive cardiac causes).
Chest compressione only CPR can be a valuable option in adult witnessed VF/pulseless VT primary cardiac arrest (delayed airway management and passive O2 administration is reasonable).
Mechanical chest compression (MCC) is the future of CPR. They still do not demonstrated evident superiority in terms of outcome respect to manual chest compressions, but are evidently not inferior with a similar rate of life treating lesions. For sure MCC avoid variability in quality and allows good quality CC during transport.
Ventilation
Lower Tidal volumes following OHCA is independently associated with favourableneurocognitive outcome
Weak evidences demonstrate that the ideal rate for ventilation of intubated patients during CPR is 10/min
Airway management
There is not beneficial effect on outcome with early intubation in Cardiac Arrest (CA).
Privilege High Quality CPR and Defibrillation (if needed).
Use Supraglottic Airway Devices (SAD) in first part (15 min) of resuscitation
If Mechanical Chest Compressions is used, to optimise ventilation with SAD, use 30:2 ratio (because the intrathoracic pressure generated during MCC overrules that generated from SAD and impaires ventilation).
In prolonged Cardiac Arrest management converting SAD to Endotracheal Tube can be considered.
Experience provider only can perform endotracheal intubation in CA. They have a better chance of first passage rate, without interruption in chest compressions. First pass success rate is positively associated to survival and good neurological outcome.
Defibrillation
Escalating bilevel energy (150-200-360 Joule) is associated with more efficacy in termination of shock resistant VF/pulselessVT cardiac arrest
Dual Sequential Defibrillation is feasible and safe. Although the evidences on its beneficial effect on outcome are still lacking it has to be considered in case of CA with refractory shockable rhythm.
Antiarrhythmics drugs
There has been no conclusive evidence that any antiarrhythmic agents improve rates of ROSC, survival to admission, survival to discharge or neurological outcomes.
Ultrasound
Ultrasound in PEA is a key tool to detect CA causes improving survivival.
Post Resuscitation Care
In post resuscitation phase avoid any arterial oxygen and carbon dioxide abnormality because are associated to increased mortality.
Centralisation of resuscitated patients toward an acute PCI/CABG capable Center is associated to better outcome.
Targeted Temperature Management
Prehospital cooling does not improve faster in-hospital target temperature achieving and due to its costs is not recommended.
If you are interested on a daily update about the best emergency medicine literature follow me on Facebook, Twitter or give your like to MEDEST Facebook page.
Risk factors for intubation related cardiac arrest are: overweight or obesity, age more than 75 years old, low SBP prior to intubation, hypoxemia prior to intubation, and absence of preoxygenation before intubation procedure.
Preoxygenation is crucial (at least 2 minutes), before paralysing, to extend safe apnea time.
Use apneic oxygenation during intubation attempts.
Tracheal intubation is good in the hands of very well skilled professionals. Otherwise can improve mortality rate.
Supraglottic devices perform well in cardiac arrest and are a valuable option for airway management.
Videolaryngoscopy improve glottic view but need training to improve first pass success.
Always use paralytics when intubating a non cardiac arrest patient. It improves the chances fo first pass success.
Rocuronium and Succynocholine are both valuable options for paralysis in airway management.
Dose Succynocholine, and other depolarising neuromuscular blockade drugs, based on actual body weight. Dose Rocuronium or Vecuronium based on ideal body weight.
Use cuffed tracheal tubes even in paediatric patients. They perform well and complications rate is the same.
The difficult airway is a myth. It’s not a matter of technique but of decision making.
If you are interested on a daily update about the best emergency medicine literature follow me on Facebook, Twitter or give your like to MEDEST Facebook page.
Rule #1 Is there extreme axis deviation during WCT
Extreme axis deviation is easy to recognize. The QRS complex will be entirely negative in either lead I or lead aVF. The presence of extreme axis deviation during a WCT rhythm is virtually diagnostic of VT.
Rule #2 Is lead V6 all (or almost all) negative?
IF ever the QRS in lead V6 is either all negative (or almost all negative) then VT is highly likely.
Rule #3 Is the QRS during WCT “ugly”?
The “uglier” the QRS the more likely the rhythm is. VT originates from a ventricular focus outside of the conduction system. As a result VT is more likely to be wider and far less organized (therefore “uglier”) in its conduction pattern
The “3 simple rules” is an extract from ACLS 2013 Arrhythmias where you can find the complete explanation and much more on arrhythmias.
Visit Ken Grauer Amazon page to find out more and discover all the amzing EKG books he wrote. They are accurate and reliable for use in many emergency situation.
I’ll include Ken’s reply in the main script of the post cause it contains some very important adjuncts and expalnations. At the end of the replay you’ll find the link to download the full text of the section regarding the WCT topic. You’ll also appreciate the perfect Ken’s italian. I’m amazed….
“Molto grazie Mario per la pubblicazione del mio consiglio su le tre semplici regole per diagnosticare VT! I’ll make a few brief additions to what Mario wrote. RULE #1 – Remember that slight or even moderate axis deviation is of no help. The QRS complex must be ALL negative in either lead I or in lead aVF. If it is – then the rhythm is almost always VT. RULE #2 – Again, moderate negativity in lead V6 is common and means nothing. But if the QRS complex in lead V6 is either all negative or shows no more than a tiny r wave – then VT is likely. This is because such marked negativity in lead V6 implies that the impulse is moving away from the apex – and that almost always means VT. RULE #3 – Supraventricular rhythms with either preexisting bundle branch block or aberrant conduction typically resemble some form of conduction defect (ie, either RBBB, LBBB or RBBB with LAHB and/or LPHB). However, if the QRS complex is amorphous (ie, very “ugly” and formless) – then it is much more likely to be originating from the ventricles. Occasionally, patients may have unusual forms of IVCD – so this rule is not 100% accurate – but it is a helpful supportive point in the differential diagnosis. For those wanting more complete description of the 3 Rules (and other pointers in assessing wide tachycardias) – feel free to download these Sections from my ACLS-2013-ePub – GO TO – https://www.dropbox.com/s/8bc9h5cumo7e4vy/8.0%2C9.0%2C10.0-%20ACLS-2013-e-PUB-WCT-Criteria-%2810-13.11-2014%29-LOCK.pdf?dl=0– Detailed description of the 3 Simple Rules begins in Section 08.17. Spero che questo vi aiuta.”
From SMACC 2013 Dr. Brian Burns (Greater Sydney Area HEMS) presents why a scalpel is an imprtant item in your emergency bag. Never miss it!
A don’t miss talk/slides for every prehospital emergency physician. The last part of the talk regards the trauma arrest algorithm: how to treat arrested trauma patient in the field.
I think every prehospital professional as to be aware about new prospective on trauma treatment. Enanching survival in trauma is one of the missions of prehospital emergency service.
So enjoy Dr Burns slides and audio on “Always carry your scalpel”
Un bisturi può essere un importante aiuto in molte situazioni difficili. Non ci credete? Ascoltate Brian Burns (Greater Sydney Area HEMS) che illustra molti utili “usi” del bisturi in medicina d’emergenza preospedaliera.
این سایت را به آن دکتوران و محصلین طب که شب و روز برای رفاه نوع انسان فداکاری می کنند ، جوانی و لذایذ زندگی را بدون چشمداشت به امتیاز و نفرین و آفرین قربان خدمت به بشر می کنند و بار سنگین خدمت و اصلاح را بدوش می کشند ، اهداء می کنم This site is dedicated to all Doctors and students that aver the great responsibility of People’s well-being upon their shoulders and carry on their onerous task with utmost dedication and Devotionاولین سایت و ژورنال انتــرنتی علـــمی ،تخـصصی ، پــژوهشــی و آمــوزشــی طبـــی در افغــانســـتان
Learning everything I can from everywhere I can. This is my little blog to keep track of new things medical, paramedical and pre-hospital from a student's perspective.
Le tue opinioni sono il nostro valore aggiunto!
MEDEST 
COVID-19 and O2 therapy. Initial prehospital approach in mild symptomatic patients.
16 MarGeneral considerations (dyspneic non infective patients)
Self Protection
The generic dyspneic patients do not pose any particular self protection issues above the general precautions
Clinical needs
Non infected dyspneic patient need moderately high FiO2 but considerately high oxygen flow rates.
The available systems we have in this moment (at least on my operative setting) to deliver normally pressured O2 are:
To satisfy the increased minute ventilation of the highly dyspneic patient Venturi mask is the best device (high flow rate) and permits at the same time to tritrate the FiO2 based on the patients need avoiding indiscriminate hyperoxygenation.
Particular considerations in dyspneic potentially infective COVID-19 patients
Disclaimer
The following considerations derived from our initial experience on the field in suspect or confirmed COVID-19 with respiratory symptoms at their presentation or in the initial phases. Those are the majority of the patients we observed till the day this post was written.
The following considerations are not intended for all the severe hypoxic patients who definitively need early intubation and positive pressure ventilation.
Clinical needs
Those are dyspneic hypoxic patients who needs moderately high FiO2 and request more gas flow rates to satisfy increased minute ventilation.
So from an exclusively clinical point of view the best way to deliver oxygen it would be a Venturi mask.
Self Protection
In the actual situation in Italy the epidemiological geographical criteria is no more reliable to identify COVID-19 patients so any prehospital healthcare professional providing direct care to a dyspneic patient needs to be protected al least with:
At the same time good practice is to reduce at minimum the number of direct caring providers, to maintain, if possible, a security distance > 1 mt, to invite any patient to wear, if tolerated, a surgical mask, and a pair of disposable gloves to minimise the risk of infection.
When providing direct care of dyspneic patients who needs O2 therapy the level of risk for droplet diffusion is generally increased cause of the presence of the gas flow.
All the available systems for oxygen delivery we mentioned above are open and allow a free exaltation of the patient in the surrounding area and potentially exposes all the healthcare caregivers to an increased risk of contamination cause of the augmented droplet dispersion and to a lack of protection.
Considerations
So when dealing with O2 therapy in the potentially infected patients we need to consider the relationship between risk of contamination and clinical efficacy of any device.
Nasal Cannula
Oxygenation –—+
Protection ++++
Nasal Cannula is the only device that permits the patient to wear a surgical mask on nose and mouth, decreasing droplet diffusion and protecting the healthcare team and at the same time maintains a certain clinical efficacy..
So my first approach is Nasal Cannula underneath a medical mask.
Utilising a different device than nasal cannula plus medical mask on the patient mouth and nose (simple, non rebreather or Venturi face mask) to deliver oxygen therapy all healthcare professionals need to be aware that the risk infection increases and the patient has no barriers and so they have to consider improving his own self protection level (N95, FPP2 mask at least)
Simple/Non rebreather Facial Mask
Oxygenation —++
Protection ++–
When you can’t reach a clinical acceptable SpO2 with nasal cannula we need to downgrade on our first goal (protection) to achieve a better clinical outcome.
Simple facial masks maintain a moderate protection form droplet spreading with a more clinical efficacy respect th the nasal cannula.
Nonrebreather facial mask either moderately protects against droplet diffusion with an improvement in FiO2 above simple face mask but the nonrebreather bag is a potential expirate gas reservoir potentially increasing the risk of spreading.
Venturi mask
Oxygenation -++++
Protection —-+
High flow titratable FiO2 in an open system mask can satisfy all minute ventilation needing guaranteeing Oxygenation at a cost of a great risk of spreading. My last choice in the scale of conventional Oxygen therapy.
References:
DSC Hui, MTV Chan, B Chow. Aerosol dispersion during various respiratory therapies: a risk assessment model of nosocomial infection to health care workers. Hong Kong Med J 2014;20(Suppl 4):S9-13
M. P. Wan , C. Y. H. Chao , Y. D. Ng , G. N. Sze To & W. C. Yu (2007) Dispersion of Expiratory Droplets in a General Hospital Ward with Ceiling Mixing Type Mechanical Ventilation System, Aerosol Science and Technology, 41:3, 244-258, DOI: 10.1080/02786820601146985
Shu-An Lee, Dong-Chir Hwang, He-Yi Li, Chieh-Fu Tsai, Chun-Wan Chen,and Jen-Kun Chen. Particle Size-Selective Assessment of Protection of
European Standard FFP Respirators and Surgical Masks against Particles-Tested with Human Subjects. Journal of Healthcare Engineering. Volume 2016, Article ID 8572493, 12 pages
Thanks for reviewing and suggesting to: Scott Weingart, Jim DuCanto, Velia Marta Antonini, Giacomo Magagnotti, Andrea Paoli and all the other colleagues and friends who supported this post
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