Ventilation during resuscitation efforts for out-of-hospital primary cardiac arrest

A mixed methods analysis of caller-emergency medical dispatcher communication during 9-1-1 calls for out-of-hospital cardiac arrest

OBJECTIVE

Recognition of out-of-hospital cardiac arrest (OHCA) during 9-1-1 calls is critically important, but little is known about how laypersons and emergency medical dispatchers (EMDs) communicate. We sought to describe 9-1-1 calls for OHCA.

METHODS

We performed a mixed-methods, retrospective analysis of 9-1-1 calls for OHCA victims in a large urban emergency medical services (EMS) system using a random sampling of cases containing the term "cardiopulmonary resuscitation" (CPR) in the EMS electronic report. A constant comparison qualitative approach with four independent reviewers continued until thematic saturation was achieved. Quantitative analysis employed computational linguistics. Callers' emotional states were rated using the emotional content and cooperation score (ECCS).

RESULTS

Thematic saturation was achieved after 46 calls. Three "OHCA recognition" themes emerged [ 1) disparate OHCA terms used, 2) OHCA mimics create challenges, 3) EMD questions influence recognition]. Three "CPR facilitation" themes emerged [ 1) directive language may facilitate CPR, 2) specific instructions assist CPR, 3) caller's emotions affect CPR initiation]. Callers were generally "anxious but cooperative." Callers saying "pulse" was associated with OHCA recognition.

CONCLUSION

Communication characteristics appear to influence OHCA recognition and CPR facilitation.

PRACTICE IMPLICATIONS

Dispatch protocols that acknowledge characteristics of callers' communication may improve OHCA recognition and CPR facilitation.

Continuous flow insufflation of oxygen for cardiac arrest: Systematic review of human and animal model studies

OBJECTIVE

To synthetize the evidence regarding the effect of constant flow insufflation of oxygen (CFIO) on the rate of return of spontaneous circulation (ROSC) and other clinical outcomes during cardiac arrest (CA).

METHODS

A systematic review was performed using four databases (PROSPERO: CRD42020071960). Studies reporting on adult CA patients or on animal models simulating CA and assessing the effect of CFIO on ROSC or other clinical outcomes were considered.

RESULTS

A total of 3540 citations were identified, of which 16 studies were included. Four studies (two randomized controlled trials (RCT), two cohort studies), reported on humans while 12 studies used animal models. No meta-analysis was performed due to clinical heterogeneity. There were no differences in the ROSC (18.9% vs 20.8%, p = 0.99; 27.1% vs 21.3%, p = 0.51) and sustained ROSC rates (16.1% vs 17.3%, p = 0.81; 12.5% vs 14.9%, p = 0.73) with CFIO compared to intermitant positive pressure ventilation (IPPV) in the two human RCTs. Survival to ICU discharge was similar between CFIO (2.3%) and IPPV (2.3%) in the largest RCT (p = 0.96). Human studies were at serious or high risk of bias. In animal models' studies, ROSC rates were presented in seven RCTs. CFIO was superior to IPPV in one trial, but was associated with similar ROSC rates using different ventilation strategies in the remaining six studies.

CONCLUSIONS

No definitive association between CFIO and ROSC, sustained ROSC or survival compared to other ventilation strategies could be demonstrated. Future studies should assess CFIO effect on post-survival neurological functions and patient-important CA outcomes.

An observational study on survival rates of patients with out-of-hospital cardiac arrest in the Netherlands after improving the 'chain of survival'

OBJECTIVES

To evaluate the impact of implemented procedures for out-of-hospital cardiac arrests (OHCAs) by determining patient outcome defined as the percentage return of spontaneous circulation at arrival at the emergency department, and 3-month and 1-year-survival rates.

DESIGN

Observational study.

SETTING

Primary emergency medical care consisting of Advanced Life Support is given by ambulance nurses and secondary care by hospitals within the mid-western part of the Netherlands covering 750 000 inhabitants.

PARTICIPANTS

433 of 500 consecutive patients with OHCA were included in the study over a 1.5 -year period.

OUTCOME MEASURES

Analysis included number of patients with return of spontaneous circulation (ROSC) when handed over to the emergency department, survival at 3 months and 1 year including a comparison with global outcome rates. We further considered the influence of gender, delays, bystander Basic Life Support, use of an automated external defibrillator, initial rhythm and mechanical thorax compression in combination with Boussignac tube ventilation.

RESULTS

13% (67/500) of the initial patient population was excluded from the analysis as reanimation in these patients was aborted due to expressed wish not to be resuscitated. Resuscitation was started by bystanders, police and/or first responders in 312/433 (72%) cases. An automated external defibrillator was used in 198 of these 312 cases (63%) of which it defibrillated 108 times. Mechanical thorax compression in combination with Boussignac tube ventilation was necessary in 277/433 patients (64%). Spontaneous circulation returned in 96/277 (35%) patients of this group. In the overall studied population, ROSC percentage at arrival at the hospital was 214/433 (49%). The 3-month and 12-month-survival rates were 123/433 (28%) and 119/433 (27%), respectively.

CONCLUSIONS

Optimised 'chain of survival' for patients with OHCA resulted in ROSC in 49% of the cases and a 1-year-survival rate of 27% in the studied population.

Advanced Airway Type and Its Association with Chest Compression Interruptions During Out-of-Hospital Cardiac Arrest Resuscitation Attempts

OBJECTIVE

To assess interruptions in chest compressions associated with advanced airway placement during cardiopulmonary resuscitation (CPR) of out-of-hospital cardiac arrest (OHCA) victims.

METHODS

The method used was observational analysis of prospectively collected clinical and defibrillator data from 339 adult OHCA victims, excluding victims with <5 minutes of CPR. Interruptions in CPR, summarized by chest compression fraction (CCF), longest pause, and the number of pauses greater than 10 seconds, were compared between patients receiving bag valve mask (BVM), supraglottic airway (SGA), endotracheal intubation (ETI) via direct laryngoscopy (DL), and ETI via video laryngoscopy (VL). Secondary outcomes included first pass success and the effect of multiple airway attempts on CPR interruptions.

RESULTS

During the study period, paramedics managed 23 cases with BVM, 43 cases with SGA, 148 with DL, and 125 with VL. There were no statistically significant differences between the airway groups with regard to longest compression pause (BVM 18 sec [IQR 11-33], SGA 29 sec [IQR 15-65], DL 26 sec [IQR 12-59], VL 22 sec [IQR 14-41]), median number of pauses greater than 10 seconds (BVM 2 [IQR 1-3], SGA 2 [IQR 1-3], DL 2 [IQR 1-4], VL 2 [IQR 1-3]), or CCF (0.92 for all groups). However, each additional attempt following failed initial DL was associated with an increase in the risk of additional chest compression pauses (relative risk 1.29, 95% confidence interval 1.02-1.64). Such an association was not observed with additional attempts using VL or SGA. First pass success was highest with SGA (77%), followed by between DL (68%) and VL (67%); these differences were not statistically significant.

CONCLUSIONS

While summary measures of chest compression delivery did not differ significantly between airway classes in this observational study, repeated attempts following failed initial DL during cardiopulmonary resuscitation were associated with an increase in the number of pauses in chest compression delivery observed.

Design of a Functional Training Prototype for Neonatal Resuscitation

Birth Asphyxia is considered to be one of the leading causes of neonatal mortality around the world. Asphyxiated neonates require skilled resuscitation to survive the neonatal period. The project aims to train health professionals in a basic newborn care using a prototype with an ultimate objective to have one person at every delivery trained in neonatal resuscitation. This prototype will be a user-friendly device with which one can get trained in performing neonatal resuscitation in resource-limited settings. The prototype consists of a Force Sensing Resistor (FSR) that measures the pressure applied and is interfaced with Arduino^® which controls the Liquid Crystal Display (LCD) and Light Emitting Diode (LED) indication for pressure and compression counts. With the increase in population and absence of proper medical care, the need for neonatal resuscitation program is not well addressed. The proposed work aims at offering a promising solution for training health care individuals on resuscitating newborn babies under low resource settings.

Oxygenation, ventilation, and airway management in out-of-hospital cardiac arrest: a review

Recently published evidence has challenged some protocols related to oxygenation, ventilation, and airway management for out-of-hospital cardiac arrest. Interrupting chest compressions to attempt airway intervention in the early stages of OHCA in adults may worsen patient outcomes. The change of BLS algorithms from ABC to CAB was recommended by the AHA in 2010. Passive insufflation of oxygen into a patent airway may provide oxygenation in the early stages of cardiac arrest. Various alternatives to tracheal intubation or bag-mask ventilation have been trialled for prehospital airway management. Simple methods of airway management are associated with similar outcomes as tracheal intubation in patients with OHCA. The insertion of a laryngeal mask airway is probably associated with worse neurologically intact survival rates in comparison with other methods of airway management. Hyperoxemia following OHCA may have a deleterious effect on the neurological recovery of patients. Extracorporeal oxygenation techniques have been utilized by specialized centers, though their use in OHCA remains controversial. Chest hyperinflation and positive airway pressure may have a negative impact on hemodynamics during resuscitation and should be avoided. Dyscarbia in the postresuscitation period is relatively common, mainly in association with therapeutic hypothermia, and may worsen neurological outcome.

A review of chest compression interruptions during out-of-hospital cardiac arrest and strategies for the future

BACKGROUND

It has been known for many years that interrupting chest compressions during cardiopulmonary resuscitation (CPR) from out-of-hospital cardiac arrest (OHCA) leads directly to negative outcomes. Interruptions in chest compressions occur for a variety of reasons, including provider fatigue and switching of compressors, performance of ventilations, placement of invasive airways, application of CPR devices, pulse and rhythm determinations, vascular access placement, and patient transfer to the ambulance. Despite significant resuscitation guideline changes in the last decade, several studies have shown that chest compressions are still frequently interrupted or poorly executed during OHCA resuscitations. Indeed, the American Heart Association has made great strides to improve outcomes by placing a greater emphasis on uninterrupted chest compressions. As highly trained health care providers, why do we still interrupt chest compressions? And are any of these interruptions truly necessary?

OBJECTIVES

This article aims to review the clinical effects of both high-quality chest compressions and the effects that interruptions during chest compressions have clinically on patient outcomes.

DISCUSSION

The causes of chest compression interruptions are explored from both provider and team perspectives. Current and future methods are introduced that may prompt the provider to reduce unnecessary interruptions during chest compressions.

CONCLUSIONS

New and future technologies may provide promising results, but the greatest benefit will always be a well-directed, organized, and proactive team of providers performing excellent-quality and continuous chest compressions during CPR.

Quantifying the effect of cardiopulmonary resuscitation quality on cardiac arrest outcome: a systematic review and meta-analysis

Background- Evidence has accrued that cardiopulmonary resuscitation quality affects cardiac arrest outcome. However, the relative contributions of chest compression components (such as rate and depth) to successful resuscitation remain unclear. Methods and Results- We sought to measure the effect of cardiopulmonary resuscitation quality on cardiac arrest outcome through systematic review and meta-analysis. We searched for any clinical study assessing cardiopulmonary resuscitation performance on adult cardiac arrest patients in which survival was a reported outcome, either return of spontaneous circulation or survival to admission or discharge. Of 603 identified abstracts, 10 studies met inclusion criteria. Effect sizes were reported as mean differences. Missing data were resolved by author contact. Estimates were segregated by cardiopulmonary resuscitation metric (chest compression rate, depth, no-flow fraction, and ventilation rate), and a random-effects model was applied to estimate an overall pooled effect. Arrest survivors were significantly more likely to have received deeper chest compressions than nonsurvivors (mean difference, 2.44 mm; 95% confidence interval, 1.19-3.69 [P<0.001]; n=6 studies; I(2)=0.0%; P for heterogeneity=0.9). Likewise, survivors were significantly more likely to have received chest compression rates closer to 85 to 100 compressions per minute (cpm) than nonsurvivors (absolute mean difference from 85 cpm, -4.81 cpm; 95% confidence interval, -8.19 to -1.43 [P=0.005]; from 100 cpm, -5.04 cpm; 95% confidence interval, -8.44 to -1.65 [P=0.004]; n=6 studies; I(2)<49%; P for heterogeneity >0.2). No significant difference in no-flow fraction (n=7 studies) or ventilation rate (n=4 studies) was detected between survivors and nonsurvivors. Conclusions- Deeper chest compressions and rates closer to 85 to 100 cpm are significantly associated with improved survival from cardiac arrest.

Correlation between capnography and arterial carbon dioxide before, during, and after severe chest injury in swine

The relationship between end-tidal carbon dioxide (EtCO(2)) and arterial carbon dioxide (PaCO(2))-if better defined-could facilitate the difficult task of ventilation in prehospital trauma patients. We aimed to study the PaCO(2)-EtCO(2) relationship before, during, and after chest trauma, hemorrhage, and resuscitation in swine. Twenty-four swine were intubated, anesthetized, and monitored in an animal intensive care unit during three phases: phase 1 (day 1, healthy animals); phase 2 (day 2, injury), which consisted of blunt chest trauma, hemorrhage, and resuscitation; and phase 3 (day 2, after injury). "Respiratory maneuvers" (changes in respiratory rate and tidal volume [TV], intended to vary the PaCO(2) over a range of 25 to 85 mmHg, were performed during phases 1 and 3. End-tidal CO(2) and PaCO(2) were recorded after each respiratory maneuver and analyzed using linear regression. During phase 1, PaCO(2) and EtCO(2) were strongly correlated (r(2) = 0.97, P < 0.01). During phase 2, animals developed decreased oxygenation (PaO(2):FiO(2) [fraction of inspired oxygen] ratio <200) and hypotension (mean arterial pressure, 20-50 mmHg); the PaCO(2)-EtCO(2) relationship deteriorated (r(2) = 0.25, P < 0.0001). During phase 3, oxygenation, hemodynamics, and the PaCO(2)-EtCO(2) relationship recovered (r(2) = 0.92, P < 0.01). End-tidal CO(2) closely correlates to PaCO(2) in healthy animals and after injury/resuscitation across a wide range of respiratory rates and tidal volumes. Once oxygenation and hemodynamics are restored, EtCO(2) can be used to predict PaCO(2) following chest trauma/hemorrhage and should be considered for patient monitoring. This work demonstrated that EtCO(2) alone can reliably be used to estimate PaCO(2) in uninjured subjects and in those subjects who have been resuscitated from severe injury. Immediately after blunt chest injury, the correlation between EtCO(2) and PaCO(2) is temporarily unstable. Under these circumstances (with abnormal oxygenation and/or hemodynamics), greater caution and other monitoring tools may be required.

Chest compressions versus ventilation plus chest compressions: a randomized trial in a pediatric asphyxial cardiac arrest animal model

PURPOSE

To compare survival, oxygenation, ventilation, and hemodynamic variables achieved with chest compressions or ventilation plus chest compressions.

METHODS

This randomized experimental study was conducted in the experimental department of a university hospital. Thirty infant pigs with asphyxial cardiac arrest were randomized into two groups of cardiopulmonary resuscitation (CPR): group 1, continuous chest compressions plus non-coordinated ventilation with a mask and mechanical ventilator (inspired oxygen fraction 0.21) (VC); group 2, chest compressions only (CC). Nine minutes of basic resuscitation was performed initially in both groups, followed by advanced resuscitation. CPR was terminated on achieving return of spontaneous circulation (ROSC) or after 30 min of total resuscitation time without ROSC.

RESULTS

Three animals (18.8%) in the VC group and 1 (7.1%) in the CC group achieved ROSC (P = 0.351). Oxygenation and ventilation during basic CPR were insufficient in both groups, though they were significantly better in the VC group than in the CC group after 9 min (PaO(2), 26 vs. 19 mmHg, P = 0.008; PaCO(2), 84 vs. 101 mmHg, P = 0.05). Cerebral saturation was higher in the VC group (61%) than in the CC group (30%) (P = 0.06). There were no significant differences in mean arterial pressure.

CONCLUSIONS

Neither of the basic CPR protocols achieved adequate oxygenation and ventilation in this model of asphyxial pediatric cardiac arrest. Chest compressions plus ventilation produced better oxygenation, ventilation, and cerebral oxygenation with no negative hemodynamic effects. Survival was higher in the VC group, though the difference was not statistically significant.

The PICU perspective on monitoring hemodynamics and oxygen transport

Alterations of hemodynamics and oxygen transport balance are very common scenarios in the pediatric intensive care unit (PICU), and these alterations are as heterogeneous and diverse in nature as are the patient populations that typically exist in the PICU. Accordingly, the PICU perspective on monitoring of hemodynamics and oxygen transport balance in critically ill children must be understood in this context of heterogeneity and diversity. We provide an interpretation of the evidence supporting various monitoring strategies as presented in the The Pediatric Cardiac Intensive Care Society Evidence Based Review and Consensus Statement on Monitoring of Hemodynamics and Oxygen Transport Balance from a Pediatric Intensive Care perspective.

Advanced airway management does not improve outcome of out-of-hospital cardiac arrest

BACKGROUND

The goal of out-of-hospital endotracheal intubation (ETI) is to reduce mortality and morbidity for patients with airway and ventilatory compromise. Yet several studies, mostly involving trauma patients, have demonstrated similar or worse neurologic outcomes and survival-to-hospital discharge rates after out-of-hospital ETI. To date, there is no study comparing out-of-hospital ETI to bag-valve-mask (BVM) ventilation for the outcome of survival to hospital discharge among nontraumatic adult out-of-hospital cardiac arrest (OOHCA) patients.

OBJECTIVES

The objective was to compare survival to hospital discharge among adult OOHCA patients receiving ETI to those managed with BVM.

METHODS

In this retrospective cohort study, the records of all OOHCA patients presenting to a municipal teaching hospital from November 1, 1994, through June 30, 2008, were reviewed. The type of field airway provided, age, sex, race, rhythm on paramedic arrival, presence of bystander cardiopulmonary resuscitation (CPR), whether the arrest was witnessed, site of arrest, return of spontaneous circulation (ROSC), survival to hospital admission, comorbid illnesses, and survival to hospital discharge were noted. A univariate odds ratio (OR) was first computed to describe the association between the type of airway and survival to hospital discharge. A multivariable logistic regression analysis was performed, adjusting for rhythm, bystander CPR, and whether the arrest was witnessed.

RESULTS

A cohort of 1,294 arrests was evaluated. A total of 1,027 (79.4%) received ETI, while 131 (10.1%) had BVM, 131 (10.1%) had either a Combitube or an esophageal obturator airway, and five (0.4%) had incomplete prehospital records. Fifty-five of 1,294 (4.3%) survived to hospital discharge; there were no survivors in the Combitube/esophageal obturator airway cohort. Even after multivariable adjustment for age, sex, site of arrest, bystander CPR, witnessed arrest, and rhythm on paramedic arrival, the OR for survival to hospital discharge for BVM versus ETI was 4.5 (95% confidence interval [CI] = 2.3-8.9; p<0.0001).

CONCLUSIONS

In this cohort, when compared to BVM ventilation, advanced airway methods were associated with decreased survival to hospital discharge among adult nontraumatic OOHCA patients.