Give back blows between the infant’s shoulder blades, on the flat upper-middle back, with the infant face-down along your forearm and the head lower than the chest. The heel of your hand strikes the midline, roughly the level of the shoulder blades, not the neck and not the lower back. Five blows, then flip and give five chest thrusts.
That placement is not arbitrary. It sits at the intersection of infant anatomy, the mechanics of a sudden pressure wave, and the narrow margin between moving an airway obstruction and injuring a 4-kilogram body.
The mechanics of a back blow in an infant
A back blow does not “knock” a object out of the throat. It produces a rapid compression of the chest wall and a sudden rise in intrathoracic pressure. That pressure is transmitted upward through the trachea, and the resulting burst of airflow can dislodge a foreign body that is wedged in the larynx or upper trachea.
Position matters because the infant is inverted. When the head is lower than the torso, gravity assists the foreign body outward rather than letting it settle deeper. The strike between the scapulae transmits force through the posterior rib cage toward the airways, which is why the midline upper back is the target and the flanks are not.
The force also has to travel through soft tissue, not bone. An infant’s ribs are pliable and the chest wall is thin. A blow delivered too high lands on the cervical spine and the base of the skull. A blow delivered too low lands on the liver or the lower ribs. The shoulder-blade level is the zone where the force couples efficiently into the chest without concentrating on a vulnerable structure.
Plain language: you are trying to squeeze the chest suddenly from behind, not hit the baby hard.
Quantified context: force, size, and timing
Infants are small and their airways are smaller. A newborn trachea is roughly 4 millimeters in internal diameter, and the narrowest point in a young infant’s airway sits at the level of the cricoid ring rather than the vocal cords. A foreign body a few millimeters across can produce near-total obstruction.
The numbers that shape the technique:
Five back blows, then five chest thrusts, repeated in cycles. This is the current infant sequence taught by major resuscitation bodies. The strike uses the heel of one hand, not the fingertips and not a fist. Head-down positioning is maintained throughout the back-blow phase. Back blows are recommended for infants under 1 year. For children over 1 year, abdominal thrusts replace chest thrusts, because the anatomy and the risk profile change.
Current guidance from the American Heart Association and the American Red Cross places infant back blows at five repetitions per cycle. The number is a compromise: enough blows to be effective, few enough to avoid cumulative trauma before reassessment.
A key threshold: if the infant is coughing forcefully, crying, or moving air, do not intervene with back blows at all. The cough is more effective than your hand. Intervention starts when the cough becomes silent or ineffective, or when the infant cannot breathe, cry, or make sound.
Timeline: what happens minute by minute
| Time from complete obstruction | What is happening | What the rescuer should be doing |
|---|---|---|
| 0–30 seconds | Airway blocked; infant may be silent, distressed, or panicked | Confirm obstruction; call emergency services or direct someone to call |
| 30 seconds–2 minutes | Oxygen reserves fall; coughing weakens | Begin cycles of 5 back blows and 5 chest thrusts |
| 2–4 minutes | Risk of hypoxic injury rises sharply | Continue cycles; do not stop to search the mouth blindly |
| 4–6 minutes | Brain injury risk becomes significant | Continue resuscitation; begin CPR if the infant becomes unresponsive |
| 6+ minutes | High risk of severe neurological injury or death | Continue until help arrives or the infant recovers |
The timeline is the argument for acting fast and for not improvising. Every pause to reposition, search, or reconsider costs seconds that the infant’s brain cannot spare.
Edge cases that change the technique
Age is the first edge case. Back blows are the infant technique, defined as under 1 year. Once a child is walking and over 1 year, abdominal thrusts become the standard for conscious choking, and the back-blow position changes in the child and adult algorithms.
Obesity and body habitus matter less in infants than in adults, but they matter at the margins. A very small or premature infant has a proportionally larger head and a more fragile cervical spine, so supporting the jaw and neck during the face-down position is critical.
A second edge case is the infant who is already limp or unresponsive. Back blows are for the conscious infant with an ineffective cough. An unresponsive infant gets CPR, not back blows, because the priority shifts from expelling a foreign body to circulating oxygenated blood.
A counterintuitive professional caveat: more force is not better. Rescuers who strike harder to “make it work” raise the risk of rib fracture, liver injury, and airway trauma without improving expulsion. The effective blow is firm and controlled, delivered with the heel of the hand.
Red-flag warnings:
Do not perform blind finger sweeps in an infant’s mouth; you can push the object deeper. Do not give abdominal thrusts to an infant under 1 year; the liver and other organs are poorly protected. Do not delay calling emergency services to keep trying solo. Do not stop cycles to hunt for the object unless you can see it. Do not use back blows on a choking infant who is coughing effectively.
Misconceptions about back-blow placement
The most common misconception is that the blow should land on the lower back or the flank, as though you were performing a Heimlich maneuver from behind. In an infant, abdominal thrusts are contraindicated, and the lower back is the wrong target for transmitting pressure to the airway.
A second misconception is that the infant should be upright. Upright positioning removes the gravity assist and changes the geometry of the force. The face-down, head-lower-than-chest position is part of the mechanism, not a detail.
A third misconception is that the neck should be struck to “open” the airway. Striking the neck risks cervical spine injury and does nothing for a laryngeal foreign body.
A fourth misconception is that back blows and chest thrusts are interchangeable. They are complementary. Back blows exploit intrathoracic pressure from behind; chest thrusts exploit it from the front. The cycle alternates because each produces a different pressure profile.
A comparison of alternatives makes the trade-offs explicit:
| Technique | Target population | Mechanism | Key risk | When it is preferred |
|---|---|---|---|---|
| Back blows (5) | Infants under 1 year | Sudden intrathoracic pressure from posterior chest compression | Cervical or rib injury if misplaced | First step in infant choking with ineffective cough |
| Chest thrusts (5) | Infants under 1 year | Anterior chest compression raising airway pressure | Rib injury, inadequate depth | Alternated with back blows |
| Abdominal thrusts | Children over 1 year, adults | Diaphragmatic compression | Liver and organ injury | Standard for older children and adults |
| Blind finger sweep | None | Mechanical removal | Pushing object deeper | Never recommended |
| CPR | Unresponsive any age | Circulation plus ventilation | None when indicated | When infant becomes unresponsive |
The table shows why the infant algorithm is distinct. The technique is matched to anatomy, not to convenience.
Putting the technique into practice
The practical sequence, in order:
Confirm the infant is choking and not coughing effectively. Look for silent distress, inability to cry, and a panicked expression. Call emergency services or have someone call while you begin. Sit or kneel and place the infant face-down along your forearm, supporting the jaw and head with your hand. Keep the head lower than the chest. Deliver five firm back blows with the heel of your hand between the shoulder blades. Turn the infant face-up and deliver five chest thrusts on the lower half of the sternum. Repeat the cycle of five and five until the object is expelled, the infant recovers, or help arrives.
The thresholds that matter: five blows per cycle, midline placement between the scapulae, head-down position, and no abdominal thrusts under 1 year. If the infant becomes unresponsive, stop back blows and start CPR.
One more practical point: get trained. The technique is simple to describe and harder to perform correctly under stress, and hands-on instruction with an infant manikin is the difference between knowing the landmark and hitting it.
Limitations and what the evidence cannot settle
The evidence base for back-blow placement is built on mechanism, anatomy, and consensus resuscitation guidance rather than on randomized trials, which are neither ethical nor practical for choking infants. That means the precise force, the exact strike point within the shoulder-blade zone, and the optimal number of blows rest on physiological reasoning and expert consensus, not on measured outcome data.
The technique also has a ceiling. Back blows cannot clear an object lodged below the reach of the pressure wave, and they cannot substitute for CPR once the infant loses consciousness. And no written description replaces supervised training, because the feel of a correct blow is learned, not read.
This article is general educational information about choking first aid, not a diagnosis or a treatment plan, and it does not replace hands-on training or professional medical advice. For an actual choking emergency, call your local emergency number immediately and follow dispatcher instructions. Consult a qualified local health professional or certified first-aid instructor for training and guidance specific to your situation.