A nasal tube for breathing is any tube or device inserted through one or both nostrils to deliver oxygen, maintain an open airway, or support ventilation. These devices range from a simple two-pronged plastic nasal cannula delivering low-flow oxygen to high-flow nasal cannula systems, nasopharyngeal airway tubes placed into the back of the throat, nasotracheal tubes threaded all the way into the windpipe, and nasal CPAP masks that apply constant air pressure. The type chosen depends on how much respiratory support a person needs and whether they are conscious, asleep, or under anesthesia.
Why the Nose Is the Starting Point
Your nose does more than just filter dust. One of its primary jobs is warming and humidifying the air you breathe before it reaches your lungs, where gas exchange happens. That conditioning process relies on evaporation of water from the moist lining inside the nasal passages.1PubMed. Observations on the ability of the nose to warm and humidify inspired air Without adequate warming and moistening, the delicate air sacs in the lungs can dry out and function poorly.2PubMed Central. Numerical simulation and nasal air-conditioning About 90% of this conditioning is finished before air even reaches the back of the nasal septum, so the front portion of the nose does most of the heavy lifting.3Scientific Reports. Effects of decongestion on nasal cavity air conditioning efficiency: a CFD cohort study
This built-in conditioning system is one reason medical devices that deliver gas through the nose work so well. A nasal cannula or high-flow system takes advantage of whatever natural warming and humidifying the nose can still provide, while the device itself can add heated, humidified gas to compensate. A tube that bypasses the nose entirely and goes straight into the mouth or throat skips that natural filter, which is why breathing through an oral endotracheal tube in an intensive care unit always requires a separate humidifier in the circuit.
The Simple Nasal Cannula
The most familiar nasal breathing tube is the standard low-flow nasal cannula: two small prongs that rest just inside the nostrils, connected by tubing to an oxygen source. It is lightweight, easy to apply, and lets you eat, drink, and talk while wearing it. Flow rates typically run from 1 to 6 liters per minute. The oxygen concentration a person actually inhales varies quite a bit depending on how fast they are breathing and whether their mouth is open, but at rest it generally ranges from roughly 26% at 1 liter per minute up to about 54% at 6 liters per minute.4PubMed. Delivered oxygen concentrations using low-flow and high-flow nasal cannulas That is a substantial boost over the 21% oxygen in room air, but for someone in severe respiratory failure, it often is not enough.
One underappreciated detail: the actual oxygen concentration reaching the lungs is not fixed the way it would be with a sealed mask. Every time you inhale, you draw in a mix of the oxygen flowing from the cannula and the room air around it. If you breathe faster or take bigger breaths, you dilute the oxygen more. In neonates and infants, the delivered concentration is strongly influenced by the baby’s tidal volume and how long each inhalation lasts, more so than by the exact shape of the nasal passage or position of the cannula prongs.5PubMed Central. Variability in low-flow oxygen delivery by nasal cannula evaluated in neonatal and infant airway replicas
High-Flow Nasal Cannula
High-flow nasal cannula, often abbreviated HFNC, is the more powerful cousin. Instead of a trickle of dry oxygen, it pushes heated, humidified air-oxygen blends through wider nasal prongs at rates up to 60 liters per minute in adults. At higher flow rates the delivered oxygen concentration can reach above 70%.6PubMed. Delivered oxygen concentrations using low-flow and high-flow nasal cannulas But oxygen delivery is only part of what makes HFNC effective.
The high flow of gas continuously flushes stale, carbon-dioxide-rich air out of the nasal passages, throat, and upper trachea. This “dead space washout” means that each new breath contains more fresh oxygen and less leftover carbon dioxide, making every breath more efficient. Imaging studies using radioactive krypton gas have shown that the speed at which gas clears the nasal cavities, pharynx, and trachea increases in a flow-dependent way as HFNC is turned up from 15 to 45 liters per minute.7PubMed Central. Nasal high flow reduces dead space A systematic review confirmed that higher flows improve oxygenation, clear dead space, and can reduce the effort of breathing, with the greatest benefit when the delivered flow exceeds the patient’s own peak inspiratory demand.8PubMed Central. The effects of flow settings during high-flow nasal cannula support for adult subjects: a systematic review
The clinical payoff is clearest in people with acute hypoxemic respiratory failure, the kind of sudden, severe oxygen deficit seen in pneumonia or acute respiratory distress. In that setting, HFNC is considered a first-line therapy and is strongly recommended over standard oxygen by European intensive care guidelines.9PubMed Central. High flow nasal cannula for adult acute hypoxemic respiratory failure in the ED setting A network meta-analysis of 23 randomized trials with nearly 5,800 patients found that HFNC at higher flow settings was linked to lower intubation rates and lower short-term mortality compared with non-invasive ventilation masks.10PubMed Central. Comparison of the efficacy and comfort of high-flow nasal cannula with different initial flow settings in patients with acute hypoxemic respiratory failure Not every meta-analysis has found a statistically clear reduction in intubation or hospital mortality, though. An earlier pooled analysis noted that the trend favored HFNC but did not cross the line of statistical significance for either outcome.11PubMed. Does high-flow nasal cannula oxygen improve outcome in acute hypoxemic respiratory failure? A systematic review and meta-analysis The difference in findings likely comes down to how high the flow was set. More recent evidence suggests that the benefit really kicks in at the higher end of the flow range, not with timid settings.
A practical advantage of HFNC that patients and nurses appreciate: most people can eat while using it. In a survey of clinicians, about 86% said patients on HFNC could have an oral diet as long as they were not on the verge of needing intubation.12PubMed Central. A Survey of Feeding Practices During High-Flow Nasal Cannula Oxygen Therapy That is a real quality-of-life difference compared with a sealed face mask, which makes eating impossible.
Nasal CPAP for Sleep Apnea
Continuous positive airway pressure, or CPAP, delivered through a nasal mask is the standard treatment for obstructive sleep apnea. The device blows a steady stream of pressurized air through the nose. The key mechanism is not about oxygen delivery; it is about splinting the airway open. During sleep, the muscles in the throat relax, and in people with sleep apnea, the soft tissue collapses inward and blocks airflow. Nasal CPAP pushes against that collapse with positive pressure, acting like a pneumatic splint to keep the passage open.13PubMed. Benefit of nasal CPAP in obstructive sleep apnea is due to positive pharyngeal pressure
Early research tried to figure out whether CPAP worked by inflating the lungs more, which might indirectly tighten the upper airway, or by directly propping the throat open. The evidence points firmly toward the splinting explanation. Studies measuring muscle activity in the upper airway found that CPAP actually decreases the electrical activity in throat muscles rather than increasing it, consistent with the airway being held open mechanically so those muscles no longer need to fight as hard.14American Review of Respiratory Disease. Nasal CPAP Therapy, Upper Airway Muscle Activation, and Obstructive Sleep Apnea The improvement in blood oxygen levels that follows is a downstream effect of keeping the airway patent, not the mechanism itself.
Nasal CPAP in Premature Infants
Neonates are obligate nasal breathers, meaning they rely almost exclusively on their noses for air intake, which allows them to breathe and nurse at the same time.15Anaesthesia & Intensive Care Medicine. Developmental anatomy of the airway Their tiny nasal passages make congestion or obstruction a serious problem. For very premature babies who struggle to breathe on their own, nasal CPAP is an alternative to putting a tube down the windpipe and connecting them to a mechanical ventilator.
A large randomized trial compared nasal CPAP started at birth with immediate intubation and ventilation in very preterm infants. Babies started on nasal CPAP had fewer days on a ventilator and needed half as much surfactant, a medication used to keep the lungs from collapsing. At 28 days, the CPAP group had a lower combined risk of death or needing supplemental oxygen. The trade-off: a higher rate of pneumothorax, with 9% in the CPAP group versus 3% in the intubation group. Still, about 46% of infants initially assigned to CPAP ended up needing intubation within the first five days anyway, so nasal CPAP does not eliminate the need for ventilators in this population, it reduces it.16PubMed. Nasal CPAP or intubation at birth for very preterm infants
Nasopharyngeal Airways in Emergencies
A nasopharyngeal airway, sometimes called an NPA or “nasal trumpet,” is a soft rubber or silicone tube inserted through one nostril and advanced until its tip sits in the back of the throat behind the tongue. It creates a channel for air to pass even when the tongue or soft tissues have fallen backward and blocked the natural airway. Unlike an oral airway, which triggers gagging in anyone who is not deeply unconscious, an NPA is generally tolerated by people who are semiconscious or have an intact gag reflex, making it especially useful in trauma and field medicine.
Updated military guidelines for tactical combat casualty care recommend considering a properly sized nasopharyngeal airway when a casualty has impaired ventilation and oxygen saturation drops below 90%, particularly during bag-valve-mask ventilation.17PubMed. Airway Management in Tactical Combat Casualty Care: TCCC Change 24-1 The NPA is compact, requires minimal training to insert, and can be placed quickly in chaotic environments where a full intubation is not feasible. It does not protect the airway from aspiration the way an endotracheal tube does, but when seconds count and the only problem is soft tissue obstruction, it can be the difference between adequate oxygen delivery and none.
Nasotracheal Intubation for Surgery
When a tube needs to go all the way into the trachea and the mouth cannot be used, nasotracheal intubation is the answer. A cuffed endotracheal tube is guided through a nostril, down through the nasal passage, past the vocal cords, and into the windpipe. This is the most common method for securing the airway during oral and maxillofacial surgery because it keeps the tube completely out of the mouth, giving the surgeon unobstructed access to the teeth, jaw, and palate.18PubMed Central. Nasotracheal Intubation: An Overview It is also chosen when a patient cannot open their mouth adequately for oral intubation, whether due to jaw spasm, prior radiation therapy to the head and neck, or infections in the throat.19Anesthesia and Pain Medicine. Nasotracheal intubation for airway management during anesthesia
Nasotracheal tubes come with their own set of complications. Nosebleeds are common because the tube must pass through the richly vascular nasal lining. Pressure injuries on the nose from the tube pressing against the skin can range from mild redness to tissue breakdown, which is why hospitals experiment with different padding materials to protect the skin during prolonged use.20PubMed Central. Comparison of 3M Restonâ„¢ Self-Adhesive Foam Pad and 3M Microfoamâ„¢ Surgical Tape in Preventing Nasal Pressure Injuries Associated With Nasotracheal Intubation: A Randomized Controlled Trial When the tube stays in for days, sinus infections become a real concern, because the tube blocks the natural drainage pathways of the paranasal sinuses.21British Journal of Anaesthesia. PARANASAL SINUSITIS: A COMPLICATION OF NASOTRACHEAL INTUBATION: Two Case Reports
When Nasal Tubes Are Dangerous
The single most feared complication of putting any tube through the nose is accidental intracranial penetration, meaning the tube enters the skull instead of following its intended path. This is rare, but it is associated with skull base fractures and previous skull base surgery. When the bony floor of the skull has been disrupted by trauma or an operation, a tube advanced through the nose can follow the path of least resistance straight through the defect and into the brain.22PubMed Central. Intracranial Injury Following Nasogastric Tube Placement After Skull Base Surgery: A Case Report and Systematic Review The risk applies not only to breathing tubes but also to nasogastric feeding tubes passed through the same nasal route.23Interdisciplinary Neurosurgery. Intracranial insertion of a nasogastric tube following septoplasty: Case report and literature review
The traditional teaching has been that known or suspected skull base fractures are an absolute contraindication to nasal intubation. That blanket rule has been questioned: a review of 160 patients with skull base fractures who were intubated nasally found no difference in complications compared with oral intubation. Some experts argue that the reason intracranial tube placements are so rarely reported is precisely because clinicians follow the traditional rule and avoid nasal routes in these patients, so we simply do not know how often it would go wrong if they did not.24British Journal of Anaesthesia. Intracranial placement of a nasotracheal tube after transnasal trans-sphenoidal surgery In practice, most emergency physicians still err on the side of caution and choose an oral route when facial or skull base trauma is suspected.
Sinus infections are a more common complication. Any tube occupying a nasal passage can obstruct sinus drainage. A nasogastric tube left in place for feeding has been documented to cause rhinosinusitis and subsequent sepsis, a risk that clinicians sometimes overlook when searching for the source of a hospitalized patient’s fever.25PubMed Central. Rhinosinusitis; a potential hazard of nasogastric tube insertion
Do Nasal Tubes Affect Your Sense of Smell
People who need supplemental oxygen for months or years understandably worry about whether a stream of dry gas blowing into the nose will damage their ability to smell. A study of subjects with chronic obstructive pulmonary disease who used nasal cannula oxygen for six months found that smell and taste scores were essentially unchanged over that period.26PubMed. Smell and taste function in subjects with chronic obstructive pulmonary disease. Effect of long-term oxygen via nasal cannulas That is reassuring for chronic users.
For short-term high-flow nasal cannula use, the news is actually positive. In patients with acute respiratory failure, switching to HFNC led to measurable improvements in olfactory function scores, likely because better oxygenation and the humidified flow improved the local nasal environment rather than harming it.27PubMed. The Impact of High-Flow Nasal Cannula on Olfactory Function The concern about smell loss from nasal tubes, in other words, does not appear to hold up in the evidence that exists.
Nasal Versus Mouth Breathing During Exercise
Outside the clinical world, there is a growing popular interest in nasal breathing as a performance strategy during exercise. The logic sounds appealing: the nose filters and conditions air, produces nitric oxide, and supposedly improves oxygen uptake. The research, however, is humbling for nasal-breathing enthusiasts. During high-intensity anaerobic exercise, one study found no differences in power output or performance between nasal and mouth breathing. Nasal breathing did reduce hyperventilation, but it came with higher heart rates during the later stages of the test, indicating greater cardiovascular strain.28PubMed Central. Effects of Nasal or Oral Breathing on Anaerobic Power Output and Metabolic Responses
For muscular endurance, the picture is similar. A study comparing nose-only, nose-and-mouth, and mouth-only breathing during resistance exercise found no significant differences in repetitions to failure, perceived effort, or oxygen saturation across any breathing mode. Men did show lower heart rates with pure nasal breathing, but women did not.29PubMed Central. Nose vs. mouth breathing– acute effect of different breathing regimens on muscular endurance The underlying reason is straightforward: the nasal passages have higher resistance than the mouth, and the ventilatory response during exercise drops in proportion to that extra resistance.30PubMed. The breathing route dependence of ventilatory responses to hypercapnia and exercise is modulated by upper airway resistance You can move the same amount of air through the nose, but your cardiovascular system has to work harder to compensate. For light to moderate activity, that trade-off may not matter. For high-intensity efforts, nasal breathing is unlikely to improve performance and may slightly increase cardiac workload. The honest takeaway from the available studies: personal preference should guide your choice when performance is the goal.
How Nasal Congestion Changes the Equation
One variable that affects every nasal breathing device is congestion. When nasal tissues swell, resistance goes up, flow drops, and the nose’s ability to condition air diminishes. Computational modeling of congested versus decongested nasal cavities found that applying a decongestant (which shrinks the swollen tissue and widens the nasal passage) paradoxically reduced air conditioning efficiency by about 35% on average, because the wider airway meant air spent less time in contact with the moist mucosal surface. Doubling the flow rate through a normal nose produced a nearly identical drop, around 33%.31Scientific Reports. Effects of decongestion on nasal cavity air conditioning efficiency: a CFD cohort study
This is relevant if you are using any nasal device. A congested patient receiving oxygen via nasal cannula will get less of the flow delivered effectively, and a decongestant may improve flow at the cost of reducing the natural humidification. High-flow systems partially sidestep the problem by supplying their own heated, humidified gas, so the nose does not have to do all the conditioning work. For CPAP users with chronic nasal congestion, many machines now include integrated heated humidifiers and adjustable pressure ramps specifically to counteract the discomfort and reduced effectiveness that congestion causes.