Chest compressions during CPR cause some degree of injury more often than most people realize. A large systematic review pooling data from over 12,000 patients found that roughly 55% had at least one rib fracture and about 24% had a sternum fracture after resuscitation. These skeletal injuries are the most common complications, but they are not the only ones. Organ damage, lung problems, and rarer vascular injuries round out a list that matters both for clinicians managing survivors and for bystanders wondering whether they might do more harm than good.
Broken Ribs and Sternum Fractures
Rib and sternum fractures dominate the injury picture. The pooled prevalence from a 2024 meta-analysis of 60 studies was 55% for one or more rib fractures and 24% for sternum fractures.1PubMed Central. Rib fractures and other injuries after cardiopulmonary resuscitation for non-traumatic cardiac arrest: a systematic review and meta-analysis Those numbers may actually undercount the problem. An autopsy-based study using whole-body CT found skeletal chest injuries in 86% of males and 91% of females, with an average of about 11 individual fractures or separations per person.2PubMed. Frequency and number of resuscitation related rib and sternum fractures are higher than generally considered The discrepancy between the meta-analysis figure and the autopsy figure comes down to how carefully you look: many fractures are hairline or non-displaced and go undetected on standard chest X-rays.
Women tend to be more susceptible to rib fractures during CPR. A prospective CT evaluation found that females had significantly more rib fractures than males, and that compressions delivered by non-physicians in the emergency department led to more fractured ribs as well.3PubMed. Chest injury following cardiopulmonary resuscitation: a prospective computed tomography evaluation The sex difference is thought to relate to differences in chest wall compliance and bone density rather than any difference in technique.
Why Bone Density and Age Are the Biggest Risk Factors
Age stands out as the strongest predictor of CPR-related injury across multiple studies. One forensic analysis found that higher age was the only independent factor associated with both CPR-induced injuries overall and serious injuries like three or more rib fractures, aortic dissection, and cardiac rupture.4PubMed Central. Aging is only significant factor causing CPR-induced injuries and serious injuries The odds of injury rose by about 7% for every additional year of age, and the odds of serious injury rose by about 9% per year.
Bone mineral density explains much of that age effect. A 2025 study found that people with osteopenia or osteoporosis sustained roughly 30–40% more rib and sternal fractures during CPR than people with normal bone density, regardless of their age.5PubMed. Low bone mineral density increases the risk of multiple rib and sternal fractures during cardiopulmonary resuscitation This is relevant because the typical cardiac arrest patient skews older, meaning the population most likely to need CPR is also the population most vulnerable to its skeletal complications. It also helps explain the higher fracture rates in women, who are more likely to have reduced bone density after menopause.
Compression Depth and Injury Risk
Current resuscitation guidelines recommend compressing the chest at least 5 centimeters deep in adults. That guidance raises an obvious question: do deeper compressions cause more damage? The data is mixed. One study that tracked compression depth alongside post-resuscitation CT scans found that in male patients, injuries were associated with deeper mean and peak compression depths. Among men compressed to depths greater than 6 centimeters, 49% had injuries compared to 28% at depths below 5 centimeters. Interestingly, no such association showed up in women.6PubMed. Deeper chest compression – more complications for cardiac arrest patients?
The clinical implication is awkward: the depth most likely to generate adequate blood flow is also the depth most likely to break ribs, at least in men. Since survival depends on effective compressions, guidelines have not backed away from the 5-centimeter minimum. The fractures, while painful and sometimes serious, are generally considered an acceptable trade-off against death from inadequate circulation.
Liver Lacerations and Other Abdominal Organ Injuries
Broken bones get most of the attention, but the organs beneath the chest wall can also take a hit. The liver is especially vulnerable because part of it sits between the lower sternum and the spine. If the rescuer’s hands are placed too low on the chest, the pointed lower end of the sternum can act like a wedge and compress the liver directly.7Journal of Trauma and Injury. Liver laceration as a post-cardiopulmonary resuscitation complication in a person with breast implants: a case report Case reports have documented severe lacerations, including a grade 4 liver injury occurring precisely in the plane between sternum and spine.8PubMed Central. Thinking Outside the “Box”: Severe Intra-Abdominal Bleeding Due to Liver Injury Post CPR
In the general population, liver lacerations after CPR are uncommon, with published rates typically around 0.6–2.1%. But certain groups face dramatically higher risk. A retrospective study of pregnant women who survived CPR found that 43% of them developed clinically significant liver lacerations requiring intervention.9PubMed. Liver lacerations as a complication of CPR during pregnancy The enlarged uterus pushes the liver upward and changes the anatomy enough that standard hand placement can direct force straight into it. A separate case report of cardiac arrest during pregnancy confirmed the same risk: a post-resuscitation CT revealed grade 4 liver laceration with active bleeding alongside bilateral pulmonary embolisms.10Resuscitation Plus. Challenges during cardiac arrest in pregnancy
The spleen and kidneys are less commonly injured but appear in autopsy and forensic series. Splenic lacerations tend to occur when compressions are off-center toward the patient’s left side.
Cardiac and Vascular Injuries
The heart itself can be damaged by the compressions meant to restart it. Pericardial effusion (fluid collecting around the heart), myocardial contusions, and in rare cases, ventricular rupture have all been documented. One case report described right ventricular rupture in a patient with acute myocardial infarction who received CPR. The rupture caused cardiac tamponade, with blood pressure crashing to dangerously low levels roughly 20 hours after resuscitation, ultimately requiring surgical drainage and repair.11PubMed Central. Right ventricular rupture induced by cardiopulmonary resuscitation The forensic literature also identifies aortic dissection as a rare but documented consequence of vigorous compressions.
These cardiac injuries are uncommon in isolation but clinically treacherous because they can mimic the hemodynamic instability that clinicians expect after cardiac arrest for other reasons. A patient who achieves return of spontaneous circulation but then deteriorates may have a tamponade or internal bleed that gets attributed to the original cardiac event rather than to CPR itself.
Lung Complications
Pneumothorax, where air leaks into the space around the lungs and prevents them from expanding fully, is relatively common after CPR and is often a downstream consequence of rib fractures. A sharp fragment of broken rib can puncture the lung lining. Pulmonary contusion, a bruise of the lung tissue itself, is less frequently reported but has been described as a complication that clinicians should consider when post-CPR chest imaging shows unexpected clouding.12Resuscitation. Unilateral pulmonary contusion following cardiopulmonary resuscitation
Aspiration of stomach contents into the lungs is another concern. The pressure swings created by chest compressions, combined with positive-pressure ventilation, can force stomach contents upward. A cadaver study found that the incidence of pulmonary aspiration was generally high when a supraglottic airway device was used during CPR, and the data hinted that pausing compressions during ventilation might offer some protection compared to continuous compressions.13PubMed Central. Regurgitation and pulmonary aspiration during cardio-pulmonary resuscitation (CPR) with a laryngeal tube: A pilot crossover human cadaver study Aspiration pneumonia is a recognized post-resuscitation complication, though one study of prehospital resuscitation found that gastric inflation itself was not independently associated with aspiration pneumonia, survival to discharge, or neurological outcomes.14PubMed Central. Gastric Inflation in Prehospital Cardiopulmonary Resuscitation: Aspiration Pneumonia and Resuscitation Outcomes
Fat and Bone Marrow Embolism
One of the more surprising complications links rib fractures to a downstream embolic event. When ribs break, fat and bone marrow particles from the fracture sites can enter the bloodstream. The pressure gradients created during ventilation may actively pull those particles into the venous circulation. An autopsy study of 100 cases with non-traumatic causes of death who all received CPR found rib fractures in every case, and the researchers proposed that the compressions themselves facilitated intake of bone marrow fat into the blood.15PubMed Central. Histopathological evaluation of autopsy cases with isolated pulmonary fat embolism (IPFE): is cardiopulmonary resuscitation a main cause of death in IPFE? A separate case report documented bone marrow particles in the pulmonary arteries as well as fat emboli with scattered blood-forming cells in the small vessels of the heart and liver.16PubMed Central. Fatal bone marrow embolism
Whether fat embolism independently contributes to death in these patients, rather than simply coexisting with it, is hard to untangle. The patients were already in cardiac arrest, and multiple organ failure is common regardless. But the finding matters for forensic pathologists trying to interpret autopsy results and for clinicians managing survivors who develop unexplained respiratory deterioration.
Many Injuries Go Undetected on Standard Imaging
One practical problem for clinicians is that standard portable chest X-rays, the imaging tool most readily available in an emergency department, miss the vast majority of CPR-related fractures. A study comparing X-ray and CT findings in cardiac arrest survivors found that of 40 patients with rib or sternal fractures on CT, only 3 were identified on X-ray, a sensitivity of just 7.5%. For pneumothorax, X-ray caught half of the cases CT revealed.17PubMed Central. The utility of computed tomography to evaluate thoracic complications after cardiopulmonary resuscitation This means that many patients who survive cardiac arrest are walking around with fractures that were never formally diagnosed, which has implications for pain management and recovery planning.
Mechanical Devices Versus Human Hands
Mechanical CPR devices, which deliver compressions via a piston or a band wrapped around the chest, were designed in part to provide more consistent compressions. The question of whether they cause more or fewer injuries than human hands has been studied repeatedly with somewhat mixed results.
A Cochrane review found no demonstrated difference in adverse events or injury patterns between mechanical and manual compressions, though the quality of the evidence was low.18PubMed Central. Mechanical versus manual chest compressions for cardiac arrest A more recent meta-analysis painted a slightly different picture: mechanical compressions were associated with a 29% higher rate of overall compression-induced injuries. However, the rate of life-threatening injuries was not significantly different between the two methods. The two approaches shared similar rates of sternal fractures, vertebral fractures, and lung, spleen, and kidney injuries. Where they diverged was in the pattern: mechanical devices were linked to more posterior rib fractures and more heart and liver lesions, while manual compressions caused fewer of those specific injuries.19PubMed. Safety of mechanical and manual chest compressions in cardiac arrest patients: A systematic review and meta-analysis
A third study found no difference in incidence or severity of injuries between the two methods, despite the fact that mechanical CPR was used for significantly longer durations. Pericardial damage was the one exception, appearing more often with mechanical devices.20PubMed. The comparison of cardiopulmonary resuscitation-related trauma: Mechanical versus manual chest compressions The overall takeaway is that mechanical devices produce a somewhat different injury profile rather than a clearly better or worse one, and neither method eliminates the risk of serious harm.
CPR in Children
The injury picture looks very different in pediatric patients. Children have much more flexible chest walls, and their ribs are less calcified than adults’. In a study of 218 children who received CPR, only 7% had at least one injury, and just 3% had injuries considered medically significant. Those significant injuries included retroperitoneal hemorrhage, pneumothorax, pulmonary hemorrhage, an epicardial hematoma, and a gastric perforation. Only one child had rib fractures.21PubMed. Pediatric injuries from cardiopulmonary resuscitation
A German forensic study found that about 28% of stillborns, newborns, infants, and toddlers had at least one CPR-related injury, but none were considered significant or life-threatening. Skeletal injuries and serious organ damage were extremely rare across all age groups in that series.22PubMed. Cardiopulmonary resuscitation-associated injuries in still-/newborns, infants and toddlers in a German forensic collective The forensic angle matters here because in cases of suspected child abuse, rib fractures found at autopsy after CPR could be mistaken for evidence of trauma. Understanding that CPR-related rib fractures in children are genuinely rare helps distinguish abuse-related injuries from resuscitation artifacts.
Do CPR Injuries Affect Survival?
This is a question that cuts both ways. On one hand, the injuries happen because someone is trying to save a life, and fractured ribs are preferable to death. On the other hand, severe injuries can complicate the recovery of someone who does achieve return of circulation.
A study of out-of-hospital cardiac arrest survivors found that patients with chest wall injuries had significantly fewer ventilator-free days and a higher mortality rate (54% versus 22%) than those without chest wall injury. Among patients who recovered neurologically, having six or more rib fractures or a single displaced fracture was associated with longer hospital and ICU stays.23Journal of Trauma and Acute Care Surgery. Chest wall injuries due to cardiopulmonary resuscitation and the effect on in-hospital outcomes in survivors of out-of-hospital cardiac arrest A separate analysis found that CPR-related injury was independently associated with 30-day mortality after adjusting for other factors, and that injury itself was predicted by older age, bystander CPR, cardiac cause of arrest, and longer CPR duration.24Resuscitation. CPR-related injuries after non-traumatic out-of-hospital cardiac arrest: Survivors versus non-survivors
Interpreting these numbers requires caution. Patients who receive longer CPR are both more likely to sustain injuries and more likely to die, but the longer CPR itself reflects a more difficult resuscitation. The injuries and the deaths share a common cause rather than one necessarily driving the other in every case.
Why Fear of Causing Injury Holds Bystanders Back
The complications described above are real, but they create a perception problem. Surveys of the general public have found that fear of causing injury is one of the reasons bystanders hesitate to perform CPR, especially on women. A study published in Circulation found that people perceived fears about inappropriate touching, accusations of sexual assault, and fear of causing physical harm as significant barriers to bystander CPR for female victims.25PubMed Central. Public Perceptions on Why Women Receive Less Bystander Cardiopulmonary Resuscitation Than Men in Out-of-Hospital Cardiac Arrest
Research into what actually motivates people to act tells a different story. Bystanders who had performed CPR in real emergencies reported that prior knowledge that they could not cause substantial harm was one of the key facilitators, alongside hands-on training and a sense of moral obligation.26PubMed Central. Lay Bystanders’ Perspectives on What Facilitates Cardiopulmonary Resuscitation and Use of Automated External Defibrillators in Real Cardiac Arrests The phrase “cannot cause substantial harm” may seem at odds with the injury data, but the framing is important: the person is already in cardiac arrest and will die without intervention. A few broken ribs are not comparable to death.
Legal protections reinforce this point. Good Samaritan statutes exist in all 50 U.S. states and protect bystanders who act in good faith during an emergency. A legal review concluded that bystanders are far more likely to face litigation for failing to intervene than for performing CPR that causes injuries.27PubMed. Risk and ROSC – Legal implications of bystander CPR The authors recommended that CPR training explicitly incorporate this information to encourage public response to cardiac arrests.
Procedural Complications During Resuscitation
Not all complications stem from the compressions themselves. Procedures performed during the resuscitation effort, like placing central venous catheters, can both cause their own injuries and interrupt the chest compressions that keep blood flowing. A study reviewing CCTV footage of resuscitation attempts found that subclavian central line placement was associated with compression pauses exceeding 10 seconds in about a third of patients, with a median pause of 15 seconds. One patient in the series developed an iatrogenic pneumothorax from the catheter placement itself.28Acute and Critical Care. Interruption of Chest Compression for Central Venous Catheterization during Cardiopulmonary Resuscitation These interruptions matter because every second without compressions reduces the chances of achieving a good outcome, creating a tension between the need for vascular access and the need for continuous blood flow.