Clinical Features and Outcomes Among Patients With Refractory Out-of-Hospital Cardiac Arrest and an Initial Shockable Rhythm

BACKGROUND

Clinical features among patients with refractory out-of-hospital cardiac arrest (OHCA) and initial shockable rhythms of ventricular fibrillation/pulseless ventricular tachycardia are not well-characterized.

METHODS

We compared clinical characteristics and coronary angiographic findings between patients with refractory OHCA (incessant ventricular fibrillation/pulseless ventricular tachycardia after ≥3 direct-current shocks) and those without refractory OHCA.

RESULTS

Between 2014 and 2018, a total of 204 patients with ventricular fibrillation/pulseless ventricular tachycardia OHCA (median age 62; males 78%) were divided into groups with (36%, 74/204) and without refractory arrest (64%, 130/204). Refractory OHCA patients had longer cardiopulmonary resuscitation (23 versus 15 minutes), more frequently required ≥450 mg amiodarone (34% versus 3.8%), and had cardiogenic shock (80% versus 55%) necessitating higher adrenaline dose (4.0 versus 1.0 mg) and higher rates of mechanical ventilation (92% versus 74%; all P<0.01). Of 167 patients (82%) selected for coronary angiography, 33% (n=55) had refractory OHCA (P=0.035). Significant coronary artery disease (≥1 major vessel with >70% stenosis) was present in >70% of patients. Refractory OHCA patients frequently had acute coronary occlusion (64% versus 47%), especially left circumflex (20% versus 6.4%) and graft vessel (7.3% versus 0.9%; all P<0.05) compared with those without refractory OHCA. Refractory OHCA group had higher in-hospital mortality (45% versus 30%, P=0.036) and greater new requirement for dialysis (18% versus 6.3%, P=0.011). After adjustment, refractory OHCA was associated with over 2-fold higher odds of in-hospital mortality (odds ratio, 2.28 [95% CI, 1.06-4.89]; P=0.034).

CONCLUSIONS

Refractory ventricular fibrillation/pulseless ventricular tachycardia OHCA was associated with more intensive resuscitation, higher rates of acute coronary occlusion, and poorer in-hospital outcomes, underscoring the need for future studies in this extreme-risk subgroup.

Effect of experimental manipulation on survival and recruitment of feral pigs

Lethal removal is commonly used to reduce the density of invasive-species populations, presuming it reduces population growth rate; the actual effect of lethal removal on the vital rates contributing to population growth, however, is rarely tested. We implemented a manipulative experiment of feral pig (Sus scrofa) populations at Fort Benning, Georgia, USA, to assess the demographic effects of harvest intensity. Using mark–recapture data, we estimated annual survival, recruitment, and population growth rates of populations in a moderately harvested area and a heavily harvested area for 2004–06. Population growth rates did not differ between the populations. The top-ranked model for survival included a harvest intensity effect; model-averaged survival was lower for the heavily harvested population than for the moderately harvested population. Increased immigration and reproduction likely compensated for the increased mortality in the heavily harvested population. We conclude that compensatory responses in feral pig recruitment can limit the success of lethal control efforts.

Change-in-ratio density estimator for feral pigs is less biased than closed mark - recapture estimates

Closed-population capture–mark–recapture (CMR) methods can produce biased density estimates for species with low or heterogeneous detection probabilities. In an attempt to address such biases, we developed a density-estimation method based on the change in ratio (CIR) of survival between two populations where survival, calculated using an open-population CMR model, is known to differ. We used our method to estimate density for a feral pig (Sus scrofa) population on Fort Benning, Georgia, USA. To assess its validity, we compared it to an estimate of the minimum density of pigs known to be alive and two estimates based on closed-population CMR models. Comparison of the density estimates revealed that the CIR estimator produced a density estimate with low precision that was reasonable with respect to minimum known density. By contrast, density point estimates using the closed-population CMR models were less than the minimum known density, consistent with biases created by low and heterogeneous capture probabilities for species like feral pigs that may occur in low density or are difficult to capture. Our CIR density estimator may be useful for tracking broad-scale, long-term changes in species, such as large cats, for which closed CMR models are unlikely to work.

Application of quality improvement techniques to the reduction of turnaround time for "STAT" and "ASAP" orders

This project educated a multidisciplinary team on the techniques of continuous quality improvement, which were then used to analyze the total medication cycle process in order to reduce the total turnaround time for STAT and ASAP orders. Members were trained in the appropriate analytical techniques, developed flow charts of the medication cycle, and developed and conducted a study of the turnaround time for STAT and ASAP orders. Three data collections were obtained: 1) baseline, 2) after flagging orders and medications to help quickly identify both, and 3) after implementation of guidelines for physicians to properly use the terms STAT and ASAP. The interventions seem to have resulted in system improvement based upon an overall decrease in turnaround time (70% for STAT orders, 54% for ASAP orders). The majority of the medication cycle time was on the patient care unit after medication delivery. Problems with the process were identified and recommendations made for future quality improvement teams.

Accuracy and time requirements of a bar-code inventory system for medical supplies

The effects of implementing a bar-code system for issuing medical supplies to nursing units at a university teaching hospital were evaluated. Data on the time required to issue medical supplies to three nursing units at a 480-bed, tertiary-care teaching hospital were collected (1) before the bar-code system was implemented (i.e., when the manual system was in use), (2) one month after implementation, and (3) four months after implementation. At the same times, the accuracy of the central supply perpetual inventory was monitored using 15 selected items. One-way analysis of variance tests were done to determine any significant differences between the bar-code and manual systems. Using the bar-code system took longer than using the manual system because of a significant difference in the time required for order entry into the computer. Multiple-use requirements of the central supply computer system made entering bar-code data a much slower process. There was, however, a significant improvement in the accuracy of the perpetual inventory. Using the bar-code system for issuing medical supplies to the nursing units takes longer than using the manual system. However, the accuracy of the perpetual inventory was significantly improved with the implementation of the bar-code system.

Tenuous Surface Layer on the Moon: Evidence Derived from Radar Observations

By radar backscattering, observations of the moon have been made which show a systematic difference between the backscattering coefficient of waves polarized in, and perpendicular to, the local plane of incidence. The results arein agreement with a model consisting of a tenuous top layer at least 10 centimeters thick, supported by a denser underlying layer.