BLS, High-Quality CPR and Choking

In depth

The one-page summary above is what the PDF prints. These sections go further.

Why rate, depth, recoil and pauses matter

Compressions produce blood flow only while they continue, and the chest must refill between them. ILCOR 2020 recommends a manual rate of 100 to 120/min (strong recommendation) and a depth of about 5 cm (strong), and suggests avoiding more than 6 cm (weak) and avoiding leaning between compressions (weak). The Korean 2025 guideline adds that depths beyond 6 cm are likely to raise complications and sets a chest compression fraction of 60% or more, kept as high as possible.

• Hand position: lower half of the sternum in adults (ILCOR 2020, weak).
• Ratio: 30:2 in adults (ILCOR 2020, weak); EMS may use 30:2 or continuous compressions with positive-pressure breaths until an advanced airway is placed (strong).
• In hospital, once a tracheal tube or supraglottic airway is in, compressions continue without pausing for breaths (AHA teaching; ILCOR 2020 states this only for EMS systems, and the pediatric review says the same).
• Rhythm checks every 2 min (ILCOR 2020, weak); Singapore 2026 says to resume compressions immediately after the shock.
• Breaths: about 1 s each, just to visible chest rise; Korea gives 500 to 600 mL (6 to 7 mL/kg) as the adult target. Forceful, fast breaths push air into the stomach (classic teaching).
• Feedback devices are suggested as part of a quality program and suggested against when used alone (ILCOR 2020, weak).
• Precordial thump: recommended against (ILCOR 2020, strong).

Surface and rescuer position

ILCOR 2020 suggests compressions on a firm surface when possible, turning on the bed's CPR (mattress-stiffening) mode during in-hospital arrest, and not moving the patient to the floor to gain depth; it made no recommendation on backboards. The Korean 2025 guideline, built on the 2025 ILCOR review, says an existing backboard may stay but placing a new one is not recommended (weak, very low certainty), and that moving to the floor delays CPR.

Rescuer position changes depth. In a simulation trial (Mayrand 2015, 55 rescuers analyzed), compressing with the arms at 90 degrees to the chest gave a mean depth of 41.4 mm against 32.2 mm at a lesser angle; a lowered bed (64 cm against 74 cm) trended deeper, and using a step stool was linked to a correct shoulder position. Even the better group averaged under the 50 mm target, which is why a feedback device and a low bed or stool matter for shorter rescuers.

Obesity: the opened sources give no different depth or rate for patients with obesity. A thick chest wall and a soft mattress mean more force is needed to reach the same depth, and compressors tire faster, so rotate early and do not interrupt compressions for a board.

Recognition, pulse checks and starting early

Unresponsiveness with absent or abnormal (agonal) breathing is treated as cardiac arrest. Professionals check breathing and pulse together for no more than 10 s; Singapore 2026 and the 2025 pediatric guidance both say to start CPR if the pulse is absent or uncertain. ILCOR 2020 strongly recommends that lay people start CPR for presumed arrest without worrying about harming someone who is not in arrest.

• Telecommunicators should coach callers into CPR (AHA 2025 Part 4, class 1); compression-only instructions for adults (class 1), conventional CPR with breaths for children and infants (class 1).
• A two-question approach (unresponsive? breathing normally?) identified 92% of out-of-hospital arrests in Part 4's evidence.
• Telecommunicator CPR was linked to more than 5 times the likelihood of bystander CPR, started 7 min sooner.
• Rescue breathing with a pulse: Korea 2025 states 1 breath every 6 s for adults (expert consensus; Singapore 2026 says every 5 s). For children and infants the 2025 pediatric review gives 1 breath every 2 to 3 s (20 to 30/min) when an advanced airway is in place or the pulse is present with inadequate breathing.
• Heart-rate rule in children: Singapore 2026 starts CPR in an unresponsive child or infant with a pulse of 60/min or less. The 2025 pediatric review says to start CPR when pulse or breathing is absent, uncertain or hard to judge and gives no rate. AHA PALS teaching (not opened here) is a heart rate under 60/min with poor perfusion.
• For an unmonitored arrest, ILCOR 2020 suggests a short period of CPR until the defibrillator is ready, then analysis without further delay.

Defibrillation details

Anterolateral placement is reasonable and anteroposterior is an acceptable alternative (ILCOR 2020), which helps when a dressing, chest tube, device or breast tissue is in the way. Pads larger than 8 cm are reasonable. Korea 2025 says the pads go on the bare chest, and in women without loosening or removing the bra and avoiding breast tissue (expert consensus). Singapore 2026 lists the preparation steps: not on a metal or wet surface, chest wiped dry, hair shaved, jewelry removed, medication patches removed and wiped.

Implanted pacemakers and ICDs do not prevent defibrillation; keep the pad off the device, at least 2.5 cm (1 in) from its edge (Febrasgo 2026), or use front-and-back placement. Singapore 2026 gives a wider margin of about four finger breadths from a pacemaker, which is more than 2.5 cm; the two figures are not the same distance, and the page uses the 2.5 cm minimum that the bank also keys. Pediatric pads: Singapore uses energy-attenuated pads for children up to 8 years or under 25 kg and adult pads if none are available; the 2025 AHA/AAP guidance likewise prefers an attenuated AED when available.

Public access defibrillation is a class 1 recommendation in AHA 2025 Part 4. In the PAD trial, a structured lay responder program with CPR and AED training produced 30 survivors among 107 arrests against 15 among 128 with CPR training alone (relative risk 2.0).

Choking: the evidence behind the sequence

There are no randomized trials comparing choking interventions. The 2025 AHA adult change rests on a cohort of 709 obstruction cases in which back blows were associated with better outcomes than abdominal thrusts or chest compressions, together with case reports of fatal injuries from abdominal thrusts such as aortic dissection and gastric rupture (Tian 2026). The sequence also now matches the pediatric one, which makes it easier to teach. ERC 2025 uses the same 5 and 5 cycles.

The MOCHI registry (Igarashi 2025, 407 Japanese adults) compared each technique with no bystander intervention: abdominal thrusts relieved the obstruction in 30% and back blows in 27%; both were linked to better neurologic outcome, and back blows also to higher 30-day survival (adjusted hazard ratio 0.52). One of 24 patients given abdominal thrusts had a pneumothorax. It did not compare the two techniques head to head.

• Unresponsive: start CPR. Compressions raise airway pressure and can move the object. Look in the mouth each time the airway is opened and remove only what you can see; blind finger sweeps are suggested against (ILCOR 2020).
• Magill forceps under direct view are an option for skilled providers in an obstruction arrest (ILCOR 2020).
• Suction anti-choking devices: ILCOR 2020 suggested against routine use; the 2025 ILCOR list dropped that line (Tian 2026), Korea 2025 still does not recommend routine use, and no source shows them better than back blows and thrusts.
• After successful thrusts or compressions, ERC and ILCOR 2025 call for evaluation by a clinician because injuries can be hidden (Tian 2026). MedlinePlus adds: seek care for a cough, fever, trouble swallowing or wheeze in the following days.
• Infants: abdominal thrusts are avoided because of the risk of liver injury (Tian 2026). Back blows alternate with 5 chest thrusts (Lee 2026, Tian 2026). The 2025 summaries opened do not name the chest-thrust hand technique; MedlinePlus (2026) shows two fingers on the center of the breastbone just below the nipple line.
• Children over 1 year: 5 back blows alternate with 5 abdominal thrusts (Lee 2026, Part 6 abstract). Adult and child chest thrusts replace abdominal thrusts in pregnancy or obesity (MedlinePlus; Korea 2025).

Children and infants

Infants are under 1 year, children run from 1 year to puberty, and adolescents follow adult BLS (Lee 2026). A single rescuer uses 30:2 at every age; two rescuers use 15:2 before puberty. Compressions are at least one-third of the chest depth. The 2025 AHA/AAP guidance dropped the two-finger infant technique because it does not reliably reach depth; the heel of one hand or two thumbs with the hands encircling the chest are both acceptable, and the heel of one hand is used if you cannot encircle the chest. Depth in centimeters: MedlinePlus (2026) gives about 5 cm for a child and about 4 cm for an infant; the 2025 pediatric review gives only one-third of the chest, and Singapore 2026 uses 4 to 5 cm (child) and 3 to 4 cm (infant).

• With an advanced airway, or a pulse with inadequate breathing: 1 breath every 2 to 3 s (20 to 30/min).
• Rescue breaths with compressions improve survival in pediatric out-of-hospital arrest; lay rescuers should give them if willing and able.
• Lone rescuer without a phone: about 2 min (5 cycles) of CPR before leaving to call (MedlinePlus).
• Infant breaths: cover the mouth and nose with your mouth (classic teaching).
• Newborns at birth follow neonatal resuscitation, and Singapore does not use an AED under 1 month.

Pregnancy, opioids and drowning

Pregnancy: once the fundus reaches the umbilicus, at about 20 weeks, the uterus compresses the vena cava when the patient is supine. A rescuer moves the uterus by hand to the left throughout CPR; Febrasgo says lateral tilting is not recommended because it lowers compression effectiveness. Hands stay on the lower sternum at normal depth and rate, and defibrillation is the same as for any adult with fetal monitors removed first (Febrasgo 2026). The hospital team prepares for emergency delivery at the site of arrest; that decision belongs to advanced providers (see OB Emergencies).

Opioids: an estimated 1 in 6 to 1 in 3 out-of-hospital arrests are overdose-related (AHA 2025 Part 4). Without a pulse, CPR and the AED come first; naloxone is given if available without stopping compressions (MedlinePlus), and the 2025 adult BLS algorithms now include it (Part 7 abstract). Part 4 supports lay possession and use of naloxone with legal protection (class 1). With a pulse and poor breathing, ventilate with a bag-mask and give naloxone.

Drowning: ventilation matters. Korea 2025 has trained responders start with breaths and recommends standard CPR with ventilation, with compression-only CPR for untrained lay rescuers. Dry the chest before the AED pads go on.

Teams, transport and debriefing

• Out of hospital, prioritizing on-scene resuscitation toward sustained return of circulation before transport can be beneficial (Part 4, class 2a); survival to discharge was about twice as high without intra-arrest transport in adults.
• Termination of resuscitation on scene is an ALS and medical-direction decision, not a BLS one.
• An ALS-level clinician at the arrest (2a) and a team large enough for separate roles (2a) are beneficial; pit-crew style role assignment is discussed in the same evidence.
• In hospital, code teams should include members with ALS training (class 1); dedicated teams with defined roles can help (2a).
• Performance-focused debriefing (2a), using the device data (2a), immediate and delayed (2a).
• Closed-loop communication: the sender gives the message and the receiver repeats it back (Bhangu 2022, Arnold 2025); announcing completion is common team practice.

Exam pearls

• Gasping plus an uncertain pulse is cardiac arrest: compress, do not recheck.
• Choking, still coughing forcefully: watch and encourage, do not hit or thrust.
• Choking, cannot speak or cough: 5 back blows then 5 abdominal thrusts, repeated; chest thrusts in late pregnancy or a large abdomen; infants chest thrusts only.
• Choking patient goes limp: floor, compressions, look before breaths, no blind sweep.
• Medication patch under a pad: remove and wipe. Pacemaker under the pad site: move the pad away or go front-and-back.
• AED says shock delivered or no shock: compressions now, not a pulse check.
• High bed and a short rescuer: lower the bed or use a stool. Patient with obesity: same depth, no pause for a board.
• Witnessed shockable arrest with an AED working: stay and work on scene; let ALS come to you.
• Leader orders a drug: repeat it back, then report it given.