Determining a safe upper limit of oxygen supplementation for adult patients: a systematic review.

OBJECTIVE: This systematic review aimed to describe the connection between the inspired oxygen fraction and pulmonary complications in adult patients, with the objective of determining a safe upper limit of oxygen supplementation. METHODS: MEDLINE and Embase were systematically searched in August 2019 (updated July 2020) for studies fulfilling the following criteria: intubated adult patients (Population); high fractions of oxygen (Intervention) versus low fractions of (Comparison); atelectasis, acute respiratory distress syndrome (ARDS), pneumonia and/or duration of mechanical ventilation (Outcome); original studies both observational and interventional (Studies). Screening, data extraction and risk of bias assessment was done by two independent reviewers. RESULTS: Out of 6120 records assessed for eligibility, 12 were included. Seven studies were conducted in the emergency setting, and five studies included patients undergoing elective surgery. Eight studies reported data on atelectasis, two on ARDS, four on pneumonia and two on duration of mechanical ventilation. There was a non-significant increased risk of atelectasis if an oxygen fraction of 0.8 or above was used, relative risk (RR): 1.37 (95% CI 0.95 to 1.96). One study showed an almost threefold higher risk of pneumonia in the high oxygen fraction group (RR: 2.83 (95% CI 2.25 to 3.56)). The two studies reporting ARDS and the two studies with data on mechanical ventilation showed no association with oxygen fraction. Four studies had a high risk of bias in one domain. CONCLUSIONS: In this systematic review, we found inadequate evidence to identify a safe upper dosage of oxygen, but the identified studies suggest a benefit of keeping inspiratory oxygen fraction below 0.8 with regard to formation of atelectases. PROSPERO REGISTRATION NUMBER: CRD42020154242.

Early hyperoxemia is associated with lower adjusted mortality after severe trauma: results from a French registry.

BACKGROUND: Hyperoxemia has been associated with increased mortality in critically ill patients, but little is known about its effect in trauma patients. The objective of this study was to assess the association between early hyperoxemia and in-hospital mortality after severe trauma. We hypothesized that a PaO2 ≥ 150 mmHg on admission was associated with increased in-hospital mortality. METHODS: Using data issued from a multicenter prospective trauma registry in France, we included trauma patients managed by the emergency medical services between May 2016 and March 2019 and admitted to a level I trauma center. Early hyperoxemia was defined as an arterial oxygen tension (PaO2) above 150 mmHg measured on hospital admission. In-hospital mortality was compared between normoxemic (150 > PaO2 ≥ 60 mmHg) and hyperoxemic patients using a propensity-score model with predetermined variables (gender, age, prehospital heart rate and systolic blood pressure, temperature, hemoglobin and arterial lactate, use of mechanical ventilation, presence of traumatic brain injury (TBI), initial Glasgow Coma Scale score, Injury Severity Score (ISS), American Society of Anesthesiologists physical health class > I, and presence of hemorrhagic shock). RESULTS: A total of 5912 patients were analyzed. The median age was 39 [26-55] years and 78% were male. More than half (53%) of the patients had an ISS above 15, and 32% had traumatic brain injury. On univariate analysis, the in-hospital mortality was higher in hyperoxemic patients compared to normoxemic patients (12% versus 9%, p < 0.0001). However, after propensity score matching, we found a significantly lower in-hospital mortality in hyperoxemic patients compared to normoxemic patients (OR 0.59 [0.50-0.70], p < 0.0001). CONCLUSION: In this large observational study, early hyperoxemia in trauma patients was associated with reduced adjusted in-hospital mortality. This result contrasts the unadjusted in-hospital mortality as well as numerous other findings reported in acutely and critically ill patients. The study calls for a randomized clinical trial to further investigate this association.

Early-onset pneumonia following bag-mask ventilation versus endotracheal intubation during cardiopulmonary resuscitation: A substudy of the CAAM trial.

AIM: Early-onset pneumonia (EOP) is a common in-hospital complication in survivors of out-of-hospital cardiac arrest. In this substudy of the CAAM trial, we aimed to compare whether bag mask ventilation (BMV) compared to endotracheal intubation (ETI) performed during cardiopulmonary resuscitation increases the risk of developing EOP. METHODS: Adult patients from the CAAM trial that survived beyond 12 h of hospitalization were included. Information about in-hospital management and outcome of study subjects was systematically collected. Our primary aim was to compare the incidence of EOP in the BMV and ETI group using a series of bivariate analysis adjusting for one variable at a time and a logistic regression controlled for survival beyond 96 h, age, gender, catecholamine administration, no flow time, and initial shockable rhythm. RESULTS: Of 627 patients from the CAAM trial that survived to hospital admission, 409 patients were hospitalized beyond 12 h and thus included (202 randomized to BMV and 20 7 randomized to ETI). Patients in the BMV group had a significantly longer period of unsecured airway during prehospital cardiopulmonary resuscitation (BMV (median): 33 min; ETI (median): 17 min, p < 0.0001). No significant difference in the development of EOP according to airway management was identified on univariate analysis (BMV: 53%, ETI: 53%, Odds Ratio 1.0 [0.7-1.5], p = 1.0). We found no difference in the development of EOP according to airway management in the series of bivariate analyses or in the multivariable regression analysis either. CONCLUSION: In this substudy of the CAAM trial, development of early-onset pneumonia in out-of-hospital cardiac arrest survivors did not depend on airway management technique during CPR.

Ketamine for rapid sequence intubation in adult trauma patients: A retrospective observational study.

BACKGROUND: In the trauma population, ketamine is commonly used during rapid sequence induction. However, as ketamine has been associated with important side effects, this study sought to compare in-hospital mortality in trauma patients after induction with ketamine versus other induction agents. METHODS: We retrospectively identified adult trauma patients intubated in the pre-hospital phase or initially in the trauma bay at two urban level-1 trauma centers during a 2-year period using local trauma registries and medical records. In-hospital mortality was compared for patients intubated with ketamine versus other agents using logistic regression with adjustment for age, gender, Injury Severity Score (ISS), systolic blood pressure (SBP) < 90 mm Hg, and pre-hospital Glasgow Coma Scale (GCS) score. RESULTS: A total of 343 trauma patients were included with a median ISS of 25 [17-34]. The most frequently used induction agents were ketamine (36%) and propofol (36%) followed by etomidate (9%) and midazolam (5%). There was no difference in ISS or the presence of SBP <90 mm Hg according to the agent of choice, but the pre-hospital GCS score was higher for patients intubated with ketamine (median 8 vs 5, P = .001). The mortality for patients intubated with ketamine was 18% vs 27% for patients intubated with other agents (P = .14). This remained statistically insignificant in the multivariable logistic regression analysis (odds ratio 0.68 [0.33-1.41], P = .30). CONCLUSIONS: We found no statistically significant difference in mortality among patients intubated in the initial phase post-trauma with the use of ketamine compared with other agents (propofol, etomidate, or midazolam).

Impact of Physician-staffed Helicopters on Pre-hospital Patient Outcomes: A systematic review.

BACKGROUND: Management of pre-hospital patients remains a challenge. In developed countries a physician-staffed helicopter emergency medical service (PS-HEMS) is used in addition to ground emergency medical service (GEMS), but the effect is debated. This systematic review aimed to evaluate the effect of PS-HEMS compared with GEMS on patient outcomes based on the published scientific literature. METHODS: Medline, EMBASE and the Cochrane Library were systematically searched on November 15, 2019 for prospective, interventional studies comparing outcomes of patients transported by either PS-HEMS or GEMS. Outcomes of interest were mortality, time to hospital and quality of life. RESULTS: The majority of 18 studies included were observational and difficult to summarize because of heterogeneity. Meta-analysis could not be carried out. Three studies found reduced mortality in patients transported by PS-HEMS compared with GEMS with Odds ratios (OR) of 0.68 (0.47-0.98); 0.29 (0.10-0.82) and 0.21 (0.06-0.73) respectively. Another two studies found improved survival with OR 1.2 (1.0-1.5) and 6.9 (1.48-32.5) in patients transported by PS-HEMS compared with GEMS. In three studies, PS-HEMS was associated with shorter time to hospital. Three studies reported quality of life and found no benefit of PS-HEMS. CONCLUSION: In this systematic review the studies comparing PS-HEMS with GEMS were difficult to summarize because of heterogeneity. We found a possible survival benefit of PS-HEMS but were unable to conduct a meta-analysis. The overall quality of evidence was low.

Cervical Spine Clearance in Trauma Patients with an Unreliable Physical Examination.

BACKGROUND: The objective of this study was to describe and compare the timing of cervical spine clearance in trauma patients with an unreliable physical examination. METHODS: We prospectively included adult trauma patients admitted with a cervical collar and an unreliable clinical examination (as defined by the NEXUS criteria) at two level 1 trauma centers: one in the USA (US) and one in Denmark (DK). We excluded patients with cervical spine injuries requiring a collar or surgery as treatment and patients with a collar placed after hospital arrival. The primary outcome was time from emergency department (ED) arrival to collar removal. Secondary outcomes included time to CT of the cervical spine (CTCS). At the US trauma center, an institutional protocol allowing cervical spine clearance exclusively by CTCS was in place. At the Danish trauma center, cervical spine clearance was based on a clinical evaluation by an orthopedic surgeon, usually after CTCS. RESULTS: A total of 113 patients were included (US: n = 56; DK: n = 57). The median age was 47 years, and 68% were males. The main reasons for an unreliable physical examination were a Glasgow Coma Scale score below 14 (35%), distracting injuries (26%), cervical spine tenderness (13%) and intoxication (13%). The injury severity score at the US trauma center was higher than at the DK trauma center (median: 17 vs. 11, p = 0.03). Both time to CTCS (median: 41 vs. 18 min, p < 0.0001) and time to collar removal (median: 1042 vs. 49 min, p < 0.0001) were significantly greater at the US trauma center. CONCLUSIONS: Time to collar removal was significantly greater in a trauma center utilizing a cervical spine clearance protocol based on CTCS. As patients may develop complications related to the collar, future studies should clarify how early removal can be implemented without increasing the risk of morbidity.

Patient experience of spinal immobilisation after trauma.

BACKGROUND: Spinal immobilisation of blunt trauma victims with potential spinal cord injury is considered standard of care. The traditional management has, however, been increasingly questioned and concerns about harm have been raised. Few studies have described the perspective of the trauma patient regarding the spinal immobilisation. The objective of this study was therefore to evaluate the patient experience of immobilisation after trauma. METHODS: We prospectively screened adult trauma patients admitted to a level 1 trauma centre for eligibility. We included adult trauma patients who had been, and remembered being, immobilised for spinal protection with a cervical collar and a spine board prehospitally or upon arrival at the trauma centre. A semi-structured interview was conducted 2 to 72 h after admission either in person or by telephone. RESULTS: One hundred and fourteen patients were eligible for inclusion based on the patient charts. Out of 98 patients assessed for participation, 48 (49%) had no memory of being immobilised. We thus included 50 patients with a median age of 37 years (IQR: 26-60) of whom 38 (76%) were men. The median injury severity score was 9 (IQR: 3-15) and the median time with a cervical collar from initial application to in-hospital removal or until the interview was given was 91 min (IQR: 72-136). Nineteen patients (38%) reported discomfort and 12 patients (24%) experienced pain related to the immobilisation. Forty patients (80%) reported a sense of protection related to the immobilisation. CONCLUSION: Discomfort related to spinal immobilisation was reported in 38% of trauma patients. However, a sense of protection was a recurring theme in 80% of the trauma patients, who recalled being immobilised. Nearly half of the awake trauma patients had no memory of being immobilised.

Spontaneous Retroperitoneal and Rectus Sheath Hemorrhage-Management, Risk Factors and Outcomes.

BACKGROUND: Spontaneous retroperitoneal and rectus sheath hemorrhage (SRRSH) is associated with high mortality in the literature, but studies on the subject are lacking. The objective of this study was to identify early predictors of the need for angiographic or surgical intervention (ASI) in patients with SRRSH and define risk factors for mortality. METHODS: We conducted a retrospective cohort study at a tertiary academic hospital. All patients with computed tomography-identified SRRSH between 2012 to 2017 were included. Exclusion criteria were age below 18 years, possible mechanical cause of SRRSH, aortic aneurysm rupture or dissection, and traumatic or iatrogenic sources of SRRSH. The primary outcome was the incidence of ASI and/or mortality. RESULTS: Of 100 patients included (median age 70 years, 52% males), 33% were transferred from another hospital, 82% patients were on therapeutic anticoagulation, and 90% had serious comorbidities. Overall mortality was 22%, but SRRSH-related mortality was only 6%. Sixteen patients underwent angiographic intervention (n = 10), surgical intervention (n = 5), or both (n = 1). Flank pain (OR 4.15, 95% CI 1.21-14.16, p = 0.023) and intravenous contrast extravasation (OR 3.89, 95% CI 1.23-12.27, p = 0.020) were independent predictors of ASI. Transfer from another hospital (OR 3.72, 95% CI 1.30-10.70, p = 0.015), age above 70 years (OR 4.24, 95% CI 1.25-14.32, p = 0.020), and systolic blood pressure below 110 mmHg at the time of diagnosis (OR 4.59, 95% CI 1.19-17.68, p = 0.027) were independent predictors of mortality. CONCLUSIONS: SRRSH is associated with high mortality but is typically not the direct cause. Most SRRSHs are self-limited and require no intervention. Pattern identification of ASI is hard.

Dental injuries in relation to general anaesthesia-A retrospective study.

BACKGROUND: Dental injuries may occur during general anaesthesia, especially during airway management. The aim of this study was to describe cases of dental injury related to general anaesthesia, focusing on the type and extent of the injuries as well as the timing of recognition. METHOD: We reviewed the nationwide electronic database available at the Danish Patient Compensation Association and scrutinized all claims classified as possible dental injuries in relation to general anaesthesia between 2007 and 2017. RESULTS: During the 10-year study period, there were 2523 claims for compensation related to anaesthesia. Of these, 552 (21.9%) were cases of possible dental injuries following general anaesthesia. The most commonly injured teeth were the central maxillary incisors with 174 (25.3%) cases related to the left and 118 (17.2%) cases related to the right incisor. The most common injuries were fractures (41.2%) and subluxations (25.9%). Airway management included the use of Macintosh laryngoscope in 296 (64.4%) cases and a supraglottic airway device in 69 (15%) cases. Claims were more frequently approved if more than two intubation attempts were used (100% vs 82.8%, RR = 0.83, 95% CI [0.78-0.88], P = 0.0037). Injuries recognized in-hospital were more frequently approved than injuries recognized after discharge (91.6% vs 70.7%, RR = 0.83, 95% CI [0.70-0.86], P < 0.0001). CONCLUSION: The most commonly reported dental injury related to general anaesthesia in the Danish Patient Compensation Association database was a fracture. Claims were more frequently approved if more than two intubation attempts were used and if the injury was recognized in-hospital.

Restrictive vs liberal oxygen for trauma patients-the TRAUMOX1 pilot randomised clinical trial.

INTRODUCTION: Hyperoxaemia is commonly observed in trauma patients but has been associated with pulmonary complications and mortality in some patient populations. The objectives of this study were to evaluate whether maintenance of normoxia is feasible using a restrictive oxygen strategy in the initial phase after trauma and to evaluate the incidence of 30-day mortality and/or major pulmonary complications. METHODS: Forty-one adult trauma patients admitted to our trauma centre were randomised to 24 hours of restrictive oxygen therapy (no supplemental oxygen if the arterial oxyhaemoglobin saturation (SpO2 ) was at least 94%, n = 21) or liberal oxygen therapy (intubated patients: FiO2 1.0 in the trauma bay, 0.8-1.0 elsewhere; spontaneously breathing patients: 15 L/min via a non-rebreather mask, n = 20). Two blinded anaesthesiologists evaluated major in-hospital pulmonary complications within 30 days. RESULTS: Protocol compliance was high, as the median arterial oxygen tension was significantly lower in the restrictive group (10.8 kPa [9.7-12.0] vs 30.4 kPa [23.7-39.0], P < 0.0001). There were seven episodes of SpO2 below 90% in the restrictive group and one episode in the liberal group. Thirty-day mortality and/or major in-hospital pulmonary complications occurred in 4/20 (20%) in the restrictive group and in 6/18 (33%) in the liberal group: two patients in each group died within 30 days and the incidence of major in-hospital pulmonary complications was 2/20 (10%) in the restrictive group and 4/18 (22%) in the liberal group. CONCLUSION: Maintenance of normoxia using a restrictive oxygen strategy following trauma is feasible. This pilot study serves as the basis for a larger clinical trial.

Cervical spinal cord injury after blunt assault: Just a pain in the neck?

BACKGROUND: We aimed to determine the incidence, risk factors, and outcomes of cervical spinal cord injury (CSCI) after blunt assault. METHODS: The ACS National Trauma Data Bank (NTDB) 2012 Research Data Set was used to identify victims of blunt assault using the ICD-9 E-codes 960.0, 968.2, 973. ICD-9 codes 805.00, 839.00, 806.00, 952.00 identified cervical vertebral fractures/dislocations and CSCI. Multivariable analyses were performed to identify independent predictors of CSCI. RESULTS: 14,835 (2%) out of 833,311 NTDB cases were blunt assault victims and thus included. 217 (1%) had cervical vertebral fracture/dislocation without CSCI; 57 (0.4%) had CSCI. Age ≥55 years was independently predictive of CSCI; assault by striking/thrown object, facial fracture, and intracranial injury predicted the absence of CSCI. 25 (0.02%) patients with CSCI underwent cervical spinal fusion. CONCLUSIONS: CSCI is rare after blunt assault. While the odds of CSCI increase with age, facial fracture or intracranial injury predicts the absence of CSCI. SUMMARY: The incidence, risk factors, and outcomes of cervical spinal cord injury (CSCI) after blunt assault was investigated. 14,835 blunt assault victims were identified; 217 had cervical vertebral fracture/dislocation without CSCI; 57 had CSCI. Age ≥55 years was found to independently predict CSCI, while assault by striking/thrown object, facial fracture, and intracranial injury predicted the absence of CSCI.

Ketamine as a Rapid Sequence Induction Agent in the Trauma Population: A Systematic Review.

The choice of drug used to facilitate endotracheal intubation in trauma patients during rapid sequence induction (RSI) may have an impact on survival. Ketamine is commonly used in the hemodynamically unstable trauma patient although it has been associated with side effects. This review sought to investigate whether ketamine should be preferred over other induction agents for RSI in trauma patients. PubMed, Embase, and the Cochrane Library were systematically searched on September 19, 2016 for studies reporting RSI of adult trauma patients with ketamine compared with another induction agent (etomidate, propofol, thiopental, or midazolam). No language restrictions were applied. The primary outcome was 30-day mortality, and secondary outcomes included information on blood transfusions, length of hospital stay, and hospital mortality. Risk of bias was assessed using the Cochrane Risk of Bias assessment tool for randomized trials and the Risk of Bias in Non-Randomized Studies of Interventions for nonrandomized studies of intervention. A total of 4 studies were included. A cohort study from 1976 compared thiopental (n = 26) with ketamine (n = 14) for RSI in trauma patients. The primary outcome was number of blood transfusions, and no significant difference was found. Risk of bias was judged to be serious. A randomized controlled trial from 2009 compared etomidate (n = 57) with ketamine (n = 47) and found no significant difference in 28-day mortality (odds ratio [OR], 0.8 [0.4-2.0]). The trial was judged to have a low risk of bias. Two cohort studies from 2015 and 2017 also compared etomidate (n = 116 and n = 526) with ketamine (n = 145 and n = 442). No significant difference in hospital mortality between the groups was observed (OR, 1.11 [0.38-3.27] and OR, 1.41 [0.91-2.16], respectively). Both studies were judged to have a moderate risk of bias, thus excluding the possibility of a meaningful meta-analysis. The study from 2017 also reported number of units of blood transfused during the first 48 hours after trauma and length of hospital stay. No significant differences were observed (OR, 1.14 [0.87-1.49] and OR, 1.1 [0.95-1.27], respectively). Extremely few studies have compared induction agents for RSI in trauma patients. No significant differences have been found in mortality, length of hospital stay, or number of blood transfusions after induction with ketamine compared to other induction agents, but a clinically relevant benefit or harm cannot be excluded.

Supplemental oxygen and hyperoxemia in trauma patients: A prospective, observational study.

BACKGROUND: Supplemental oxygen is recommended during the initial treatment of trauma patients according to several guidelines, but the supporting evidence is sparse. We aimed to describe the use of supplemental oxygen and occurrence of hyperoxemia in the initial phase of trauma management at two level 1 trauma centers, TC1 and TC2. METHODS: In this prospective, observational study we included trauma patients ≥16 years of age. Data on pre- and in-hospital supplemental oxygen, arterial oxygen tension (PaO2 ), and outcomes (in-hospital mortality, hospital- and intensive care unit length of stay) were collected. RESULTS: We included 56 patients. There were 22 (39%) females with a mean age of 49 years (SD: 18) and a median Injury Severity Score of 9 (IQR: 4-14, n = 49). A total of 23 (45%) out of 51 spontaneously breathing patients received pre-hospital supplemental oxygen, but did not differ significantly from the patients that did not receive supplemental oxygen. In-hospital, 29 (59%) out of 49 spontaneously breathing patients received supplemental oxygen. The median PaO2 was 26.5 kPa [IQR: 22.2-34.1] in four intubated patients and 12.3 kPa [IQR: 9.7-25.7] in eight patients with spontaneous respiration on supplemental oxygen. At TC1 a significantly greater proportion of spontaneously breathing patients received both pre-hospital (TC1: 18 [64%]; TC2: 5 [21%], P = 0.002) and in-hospital (TC1: 24 [92%]; TC2: 7 [30%], P < 0.001) supplemental oxygen. CONCLUSION: Approximately 50% of trauma patients received supplemental oxygen during the initial treatment. Hyperoxemia was a common finding for patients treated with supplemental oxygen, and it was more pronounced in intubated patients.

Are surgeons reluctant to accurately report intraoperative adverse events? A prospective study of 1,989 patients.

BACKGROUND: The true incidence of intraoperative adverse events (iAEs) remains unknown. METHODS: All patients undergoing abdominal surgery at an academic institution between January and July 2016 were included in a prospective fashion. At the end of surgery, using a secure REDCap database, the surgeon was given the Institute of Medicine definition of intraoperative adverse events and asked whether an intraoperative adverse event had occurred. Blinded reviewers systematically examined all operative reports for intraoperative adverse events and their severity. The response rate and the intraoperative adverse event rate reported by surgeons were calculated. The latter was compared with the rate of intraoperative adverse events detected by operative report review. The severity of intraoperative adverse events was assessed based on a previously validated intraoperative adverse event classification system. RESULTS: A total of 1,989 operations were included. The surgeons' response rate was 71.9%, reporting intraoperative adverse events in 107 operations (7.5%). Of those intraoperative adverse events, 26 (24.3%) were not described in the operative report. Operative report review revealed intraoperative adverse events in 417 operations (21.0%). Most injuries were of lower severity (85.8% were either class I or II). The surgeons' response rate was similar in operations with and without intraoperative adverse events (69.8% versus 72.5%, P=.28), but they underreported low severity intraoperative adverse events-only 13.2% of class I compared with 35.3%, 36.8%, and 55.6% of injury classes II, III, and IV respectively (P<.001). CONCLUSION: Surgeons are willing to report intraoperative adverse events, but systematically and significantly underreport them, especially if they are of lower severity. This is potentially related to the absence of a clear intraoperative adverse event definition or their personal interpretation of their clinical significance.

The Effects of Public Access Defibrillation on Survival After Out-of-Hospital Cardiac Arrest: A Systematic Review of Observational Studies.

BACKGROUND: Despite recent advances, the average survival after out-of-hospital cardiac arrest (OHCA) remains <10%. Early defibrillation by an automated external defibrillator is the most important intervention for patients with OHCA, showing survival proportions >50%. Accordingly, placement of automated external defibrillators in the community as part of a public access defibrillation program (PAD) is recommended by international guidelines. However, different strategies have been proposed on how exactly to increase and make use of publicly available automated external defibrillators. This systematic review aimed to evaluate the effect of PAD and the different PAD strategies on survival after OHCA. METHODS: PubMed, Embase, and the Cochrane Library were systematically searched on August 31, 2015 for observational studies reporting survival to hospital discharge in OHCA patients where an automated external defibrillator had been used by nonemergency medical services. PAD was divided into 3 groups according to who applied the defibrillator: nondispatched lay first responders, professional first responders (firefighters/police) dispatched by the Emergency Medical Dispatch Center (EMDC), or lay first responders dispatched by the EMDC. RESULTS: A total of 41 studies were included; 18 reported PAD by nondispatched lay first responders, 20 reported PAD by EMDC-dispatched professional first responders (firefighters/police), and 3 reported both. We identified no qualified studies reporting survival after PAD by EMDC-dispatched lay first responders. The overall survival to hospital discharge after OHCA treated with PAD showed a median survival of 40.0% (range, 9.1-83.3). Defibrillation by nondispatched lay first responders was associated with the highest survival with a median survival of 53.0% (range, 26.0-72.0), whereas defibrillation by EMDC-dispatched professional first responders (firefighters/police) was associated with a median survival of 28.6% (range, 9.0-76.0). A meta-analysis of the different survival outcomes could not be performed because of the large heterogeneity of the included studies. CONCLUSIONS: This systematic review showed a median overall survival of 40% for patients with OHCA treated by PAD. Defibrillation by nondispatched lay first responders was found to correlate with the highest impact on survival in comparison with EMDC-dispatched professional first responders. PAD by EMDC-dispatched lay first responders could be a promising strategy, but evidence is lacking.