Manual ventilation with a bag-valve-mask device requires a good mask seal against the face in order to generate the pressure to inflate the lungs. But it also requires knowledge of how to effectively use the ventilation device to deliver a breath. This article will discuss the differences in ventilation technique for self-inflating vs free-flow ventilation bags. Understanding those differences is important for successful manual ventilation of your patient. Continue reading
Alveolar gas exchange depends not only on ventilation of the alveoli but also on circulation of blood through the alveolar capillaries. In other words it depends both on ventilation and perfusion. This makes sense. You need both oxygen in the alveoli, and adequate blood flow past alveoli to pick up oxygen, other wise oxygen cannot be delivered. When the proper balance is lost between ventilated alveoli and good blood flow through the lungs, ventilation perfusion mismatch is said to exist.
The ventilation/perfusion ratio is often abbreviated V/Q. V/Q mismatch is common and often effects our patient’s ventilation and oxygenation. There are 2 types of mismatch: dead space and shunt.
This article will describe how dead space is different from shunt. It will help you understand how you can use these concepts to care for your patient. Continue reading
Direct laryngoscopy depends on being able to bring the 3 axes of the airway into alignment to see the larynx. Curved blades are commonly used, especially by beginners because they are more forgiving of less than optimal placement and provide more room to pass the tube. However, it’s important to use them correctly. This article will discuss intubation technique using a curved blade. Straight and curved blades use different techniques for bringing the larynx into view. For a discussion of how to use a straight blade click here. Continue reading
There is nothing quite as scary as being in the middle of administering an anesthetic and having your anesthesia machine fail. In my 36 years of anesthesia practice I’ve had this happen to me a few times. Knowing how to quickly troubleshoot your machine, and knowing how to protect your patient are important, potentially life-saving skills. It helps to have thought through the steps to rescue the situation before it happens to you.
Here I describe how I learned this lesson the hard way on a volunteer medical mission to rural Honduras. When my machine failed, I was poorly prepared and this forced crisis management that I could easily have avoided with a little forethought and preparation.
Although the initial FDA warnings about potentially fatal overdose from codeine in children were released in 2012, I’m recently discovered that a few of my surgeon and nursing colleagues were still unaware of the potential risks. Therefore I thought it might be helpful to bring up the topic so people can remind their own colleagues of the risks of codeine in children.
Codeine must be used with extreme caution, if at all, in young children or pregnant women because of variants in the enzymes some patient’s use to metabolize the drug. Continue reading
Learning intubation technique can be challenging. Fall is the time of year when new students commonly begin to learn how to intubate. My first intubation was one of the first times I literally held someone’s life in my hands. I was nervous. The anesthesiologist teaching me tried to not look too anxious as I awkwardly grabbed my laryngoscope blade, fumbled while opening the patient’s mouth, and cautiously maneuvered the endotracheal tube into the trachea. It felt like time stopped until the tube was in place, after which the three of us (me, my teacher and my patient) all took a deep breath. Since then, over the last almost 37 years, I’ve intubated thousands of people in the U.S. and, as an international volunteer, eight countries.
So I thought it would be helpful at this time of year to discuss a step-by-step approach to intubation with the commonly used curved blade. Intubation, like a dance, is composed of steps that flow naturally from one to the next. The trick to a smooth intubation is to allow each step to blend seamlessly into the next. The text and illustrations below are excerpted from my book Anyone Can Intubate, as well as from my upcoming book on pediatric intubation, which I’m busy writing. Continue reading
To teach intubation skills on living patients, even those that have practiced on a manikin, can be challenging. With fall comes the new crop of trainees eager to learn how to intubate. There will also be a new group of instructors teaching their first students to intubate. It’s important to anticipate the common errors so we can safeguard our patients. Here I describe the all of the barriers, physical as well as psychological, that interfere with your student’s learning of the intubation technique. I offer tips on how to help your student conquer those barriers, while keeping your patient safe. Continue reading
When I was training, awake intubation for anticipated difficult airway was routine. Blind nasal intubation and fiberoptic intubation were common events. The advent of video laryngospcopy has made the need for awake intubation much less common. Instruments like the Glidescope and the McGrath video laryngoscope have revolutionized intubation, and made the difficult intubation scenario fortunately much more uncommon.
However, awake intubation with the patient breathing spontaneously is still sometimes optimal for patient safety. Awake intubation can be performed using standard laryngoscopy techniques, but it is more commonly done using specialty intubation techniques such as blind nasal or fiberoptic intubation.
Many providers are uncomfortable with performing awake intubations and leave it as a last resort. There are a variety of reasons for this discomfort, including lack of experience and/or the fear that the patient will remember the intubation and think poorly of their care. However, awake intubation can be a safe and comfortable strategy in many clinical situations and all providers should develop expertise with one or more techniques of choice — before an emergency forces them to use one.
This article will discuss how to decide when to do an awake intubation. Future articles will discuss how to do them. Continue reading
I recently had the incredible opportunity to visit Svalbard, Norway, an archipelago above the Arctic Circle about 600 miles from the North Pole. We were lucky enough to see polar bears, including a rare sighting of a Mom with 3 cubs.
The landscape was breathtakingly beautiful. But underlying the minute to minute magic was the sober message that the climate was warming and the ice was melting.
We passed glacier after glacier that used to fill the fjords we were sailing through, but which now clung to the sides of the canyon walls. Our ship, the National Geographic Explorer, was able to circumnavigate the Svalbard archipelago, something that has rarely been done because the northern ice usually blocks the eastern islands. Those polar bears, and indeed our planet, are in trouble.
However, I came home comfortable in my own mind that I was already doing my part to decrease global warming: using LED light bulbs, solar power, hybrid car, turning off all electrical devices when not in use. Ironically, I soon discovered that the anesthetic gases I use every day are some of the most potent greenhouse gases on the planet.
When we administer anesthesia, we pay a great deal of attention to the concentration of nitrous oxide and halogenated agents such as sevoflurane or desflurane that our patient receives. We know that too much or too little of these gases can harm our patients. We are often less compulsive about avoiding exposure to ourselves, or even our Operating Room colleagues to waste anesthetic gases. Therefore, to remind everyone of best practices on how to protect ourselves from exposure, I’ve been part of a team collaborating with our Workplace Safety department to create a training video on how to minimize Waste Anesthesia Gas (WAG) exposure. Continue reading
Since its invention, the Laryngeal Mask Airway, or LMA, has become quite valuable as a surgical airway alternative to intubation. When I first started in anesthesia, the only way to avoid intubation during surgery was to manually assist ventilation with a bag-valve-mask attachment. Cases that went on for hours often resulted in cramped fingers, and sometimes progressively poorer ventilation over time as the hand holding the mask became overly tired. A poor mask seal could potentially cause the stomach to distend with air, pushing up the diaphragms, limiting tidal volume, and increasing the risk of aspiration. The LMA has changed anesthesia so much that residents now find it challenging to find cases to practice their masking skills.
However, the LMA is so commonly used, and so apparently safe, that it’s easy to become complacent. Research is showing that it’s apparently very common for us to over-inflate our LMA cuffs — to the potential harm of our patients. Continue reading
It’s extremely easy to make any otherwise routine intubation difficult just by failing to properly position the patient or to use optimal technique. We’ve all done it. Let’s see how to avoid this pitfall. (All illustrations by Christine Whitten MD, Anyone Can Intubate). Continue reading
This article discussion some of the key anatomy, physiology, and technical points to intubating an infant or small child safely. I’ve been hard at work on writing and illustrating my upcoming book on pediatric airway management so I thought I would spend some time talking about care of our littlest patients.
Providers who infrequently care for children less than two years of age are often rightfully anxious when faced with a sick child, especially if airway management is required. This is especially true if the child is less than one. Healthy respect is certainly indicated because airway complications are one of the leading causes of pediatric cardiac arrest.
Children are not small adults. From infants to toddlers to teenagers, the anatomy and physiology of the child is continuously morphing until finally reaching the adult form and function. We all know this instinctively. When we look at a child we can often tell how old he or she is simply by looking at head size, characteristics of the face, length of neck, shape of the body, and how long the arms and legs are related to the trunk. It should not be surprising that the inside of the child is changing as well.
Infants and young children are small. The head of a newborn infant can fit on the palm of my hand. The palm of a premature infant’s hand may be the same size as my thumbnail. It’s challenging to open the airway of such a small infant when adult fingers dwarf the size of the baby’s mouth and all of the instruments are smaller. And babies are fragile, with little reserve.
Like adults, children can be small or tall, lean or overweight. But unlike adults, their airway anatomy is changing shape and structural relationships as they grow. A particular 2 year old may be as tall as a particular 6 year old, or as heavy as a particular 8 year old, but all have very different airways.
Intubating an infant or small child is more of a challenge than an older child or adult both because of their anatomical differences as well as their physiologic predisposition for hypoxia. One can certainly argue that faced with elective care, that only experienced providers should manage the airways of infants and children less than two. However, medical care is not always elective.
Faced with a sick child, especially in more urgent settings, anyone who can ventilate and intubate an adult can also ventilate or intubate an infant or toddler safely —if they take the differences in anatomy and physiology into account, and are gentle and methodical in their approach. Illustrations and photos from Anyone Can Intubate: a Step by Step Guide, and Pediatric Airway Management: a Step by Step Guide. Continue reading
Hand fatigue during mask ventilation can cause loss of the ability to maintain a good mask seal. Those of us who mask ventilate patients have all been there. We’ve been mask ventilating a patient with a bag-valve-mask device during a prolonged and difficult intubation process and our hand holding the mask starts to cramp.
As an anesthesia provider I often ventilate patients with bag-valve-mask devices. Of course we need to know how to manage the airway during emergency situations in the ICU or emergency room. When we administer general anesthesia, we mask ventilate both at the beginning and at the end of a case.
For some surgical procedures we may even allow the patient to breathe anesthetic gas spontaneously through a mask during the entire surgical procedure, requiring us to hold the airway open, assist ventilation as needed, and stay out of the surgeon’s way. Laryngeal mask airways are often used these days for such cases, but in the old days the choice was either mask ventilation or intubation.
With mask ventilation, it’s important to know how to open the airway and provide positive pressure breaths. However, it’s also important to know how to do so in a way that conserves your grip strength. Ventilating with a mask can be very tiring to your hand. Prolonged “masking” can tire your hand to the extent that you lose grip strength and coordination — making maintenance of an open airway harder to sustain over time. When I’m working with a new student, and when appropriate to the case, I often have them hold the mask during the entire anesthesia because it helps them improve their skills. So how do you effectively and efficiently ventilate while minimizing hand fatigue? Let’s look at the steps to follow. Continue reading
Positioning the head and neck for intubation in the sniffing position can make intubation easy, or extremely hard. Many years ago our operating room administration decided that the bath towels we were using to position the head for intubation were a potential danger for shedding lint. So one night, in their infinite wisdom, the towels were all summarily confiscated and when we arrived the next morning there wasn’t a single towel to be found, ever again. It may be an exaggeration to say that chaos ensued, but it felt like that.
The reason this event is so memorable is that for the next several days our anesthesia providers had trouble intubating. We likened it to an expert golfer who, when suddenly faced with a new set of golf clubs of slightly different weight and length, suddenly has to relearn the game. It made us realize that how we position the head in the sniffing position often sets us up for either an easy or for a more difficult intubation if you don’t realize what’s happening during the positioning. Continue reading
When we place anything in the mouth, be it an endotracheal tube, oral airway or LMA, we are typically extremely careful to protect the teeth. We take care to avoid cutting the lips with the teeth. But we often take the safety of the tongue for granted. I recently recognized a potential problem while using an LMA supreme that could have caused tongue ischemia if not corrected. Let we show you what happened so you can be on guard with your own patients. Continue reading
While breathing room air, oxygen saturation drops precipitously to below 90% within about a minute of the start of apnea in the average healthy adult. As we saw in a previous blog post, preoxygenation is one of the most important safety measures we can use prior to induction of anesthesia and in preparation for intubation. Adequate preoxygenation can more than double the time to hypoxia during open airway apnea, allowing more time for intubation to occur. However, increasing the time to critical hypoxia from 1 minute to 2 or 3 minutes with preoxygeation, as important as that is, can still be too short if the intubation turns out to be truly challenging. Apneic oxygenation is an easy technique to increase the time to desaturation significantly. However you have to know how to optimally provide it in order to safeguard your patient Continue reading
While breathing room air, oxygen saturation drops precipitously to below 90% within about a minute of the start of apnea in the average healthy adult. One of the most important safety measures we use in anesthesia is to preoxygenate our patients prior to induction of anesthesia and in preparation for intubation. This is especially true if we are planning a rapid sequence induction. Adequate preoxygenation can more than double the time to hypoxia during apnea, allowing more time for intubation to occur.
Preoxygenation increases the margin for safety. It treats any pre-existing hypoxemia in the critically ill patient. It also postpones the onset of hypoxia while the patient is apneic during the intubation attempt. This becomes especially important if the intubation attempt becomes difficult and prolonged.
Speed of onset of hypoxia with apnea depends on metabolic rate and on the actual amount of oxygen available in the patient’s functional residual capacity. To see how preoxygenation can effect this let’s review some physiology. Continue reading
As an anesthesiologist, I often run to emergencies where the patient is not breathing adequately and requires intubation. However, before any intubation, a patient in respiratory distress/failure needs ventilation. Providers who have passed ACLS are often able to ventilate an apneic patient well because they have practiced on the manikin. However, I often see that providers have more difficulty trying to assist ventilation of a patient who is still breathing spontaneously.
The typical inexperienced provider will try to provide large, slow breaths just as they were taught in ACLS. Unfortunately these breaths are often out of synch with the patient’s own breathing. Squeezing the bag while the patient is exhaling means that your inflation pressure must not only overcome the diaphragm, but also reverse the passive outflow of air, the elastic recoil of the lungs, and the rebound of the chest wall combined. The vocal cords may be closed. Ventilating out of synch with the patient won’t be as effective. The breath you deliver will take the path of least resistance to enter the stomach or escape from the mask. It often makes the patient cough.
Even worse, providers will occasionally hesitate to try to assist a patient’s breathing while waiting for the intubation team because they feel they don’t know how. Delay in improving ventilation can place your patient at higher risk of complication. This is unfortunate because in many ways assisting ventilation is even easier than manually ventilating an apneic patient. Let’s see why. Continue reading
There is often a great deal of confusion about how to manage the care of a patient with COPD because of unwarranted, and incorrect, concern that all patients with COPD are CO2 retainers. This fear of causing CO2 retention sometimes causes providers to withhold or withdraw oxygen inappropriately. Understanding some of the respiratory physiology behind CO2 retention will allow you to make more informed decisions. Let’s start at the beginning. Some of this material comes from my book Anyone Can Intubate, 5th Edition. Continue reading
Assessing extubation criteria, and then deciding when to extubate a patient safely can sometimes be a difficult decision.
We all know the common extubation criteria:
- recovery of airway reflexes and response to command;
- inspiratory capacity of at least 15 ml/kg;
- no hypoxia, hypercarbia, or major acid/base imbalance;
- no cardiopulmonary instability;
- signs of intact muscle power;
- absence of retraction during spontaneous respiration;
- absence of a distended stomach.
In other words, you want your patient to be stable, able to breathe without help, and able to protect the airway.
However, sometimes the decision is not so easy. Here I describe a case of a patient who met some but not all of the criteria for extubation. The reason turned out to be due to a rare complication: plugging of the endotracheal tube. However, getting to that solution required working through the extubation algorithm. Continue reading