The Role of Extra Corporeal Membrane Oxygenation for Treatment of the Adult Respiratory Distress Syndrome: Review and Quantitative Analysis

The role of Extra corporeal membrane oxygenation (ECMO) has not been formally validated for patients with adult respiratory distress syndrome. In anticipation of publication of the conventional ventilation versus ECMO in severe adult respiratory failure (CESAR) trial, the role of ECMO in this setting was reviewed.

An electronic search for studies reporting the use of ECMO for the treatment of adult respiratory distress syndrome revealed two randomised controlled trials and three non-controlled trials. Bayesian analysis on the two randomised controlled trials produced an odds ratio mortality of 1.28 (credible interval 0.24 to 6.55) demonstrating no significant harm or benefit. Pooling was not possible for the non-controlled studies because of differing admission status and ECMO selection criteria and an inability to control for these differences in the absence of individual patient data. A large number (n=35) of case series have been published with generally more positive results. We also present a comprehensive narrative commentary on the history, current practice and future for ECMO.

ECMO, as rescue therapy for adult respiratory distress syndrome, appears to be an unvalidated rescue treatment option. Analysis and review of trial data does not support its application; however the body of reported cases suggests otherwise. Until the CESAR trial provides an authoritative answer ECMO will continue to be offered on a case by case basis.

Trends in the methodological quality of published randomized controlled trials on antibacterial agents

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Randomized controlled trials (RCTs) are believed to be one of the best methods of clinical research because they can minimize systematic errors of various types. Temporal trends in the various aspects of RCTs have been studied in several medical fields (e.g. nephrology, hepatology, oncology). However, there is lack of data regarding the trends in the methodological quality of RCTs focusing on antimicrobial agents.

WHAT THIS STUDY ADDS

Several important methodological aspects of RCTs on antibacterial agents, such as description of randomization, double blinding, description of the blinding and allocation concealment, have not improved during the last 30 years. AIM To investigate the trends of the methodological quality of randomized controlled trials (RCTs) of antimicrobial agents published during the last 30 years.

METHODS

We randomly selected from the Cochrane Central Register of Controlled Trials database 70 RCTs of antibacterial agents that were published during a 30-year study period (1975-2005); specifically, we randomly selected 10 RCTs published during each of the following years: 1975, 1980, 1985, 1990, 1995, 2000 and 2005. In each of the selected RCTs, we searched for information on various methodological aspects and graded the methodological quality of the RCTs to evaluate trends for possible improvement.

RESULTS

No improvement was noted in most of the analysed methodological aspects of the RCTs during the 30-year study period. Description of randomization, double blinding, description of the blinding, and allocation concealment were rather scarce among the evaluated RCTs, without observing a trend for improvement during the study period. We noted improvement in reporting power of the study calculations, baseline data as well as in reporting the presence or not of statistical significance and the statistical cut-off of significance. In only 1/70 RCTs were all 13 of the examined methodological quality aspects met and in one more RCT 12 of them were met.

CONCLUSIONS

We did not observe considerable improvement in the quality of the reporting and methodology of RCTs on antibacterial agents during the last 30 years. The methodological quality aspects that need most improvement are those that help safeguard against various types of biases.

Scales to assess the quality of randomized controlled trials: a systematic review

BACKGROUND AND PURPOSE

The methodological quality of randomized controlled trials (RCTs) is commonly evaluated in order to assess the risk of biased estimates of treatment effects. The purpose of this systematic review was to identify scales used to evaluate the methodological quality of RCTs in health care research and summarize the content, construction, development, and psychometric properties of these scales.

METHODS

Extensive electronic database searches, along with a manual search, were performed.

RESULTS

One hundred five relevant studies were identified. They accounted for 21 scales and their modifications. The majority of scales had not been rigorously developed or tested for validity and reliability. The Jadad Scale presented the best validity and reliability evidence; however, its validity for physical therapy trials has not been supported.

DISCUSSION AND CONCLUSION

Many scales are used to evaluate the methodological quality of RCTs, but most of these scales have not been adequately developed and have not been adequately tested for validity and reliability. A valid and reliable scale for the assessment of the methodological quality of physical therapy trials needs to be developed.

The quality of trials in operative surgery

OBJECTIVE

This study aimed to assess the reported quality of trials in operative surgery.

SUMMARY BACKGROUND DATA

Randomized controlled trials (RCTs) in operative surgery have previously been criticized for using weak methodology despite no evidence to suggest their quality is any different from nonsurgical trials.

STUDY DESIGN

All surgical RCTs published in the British Medical Journal, the Journal of the American Medical Association, The Lancet, and the New England Journal of Medicine between 1998 and 2004 were identified. The adequacy of the reported methodology used to perform the randomization, power calculation, and recruitment was assessed for each trial using predefined criteria. The results from the surgical trials were compared with a randomly selected control group of nonsurgical RCTs, which were matched for journal and year of publication.

RESULTS

Sixty-six surgical RCTs were identified. Adequate reporting of randomization sequence generation was seen in 42% (n = 28) of surgical trials and 30% (n = 20) of nonsurgical trials, and adequate allocation concealment was recorded in 46% (n = 30) and 47% (n = 31), respectively. When combining these 2 interrelated steps of randomization, only 26% (n = 17) of surgical trials and 23% (n = 15) of nonsurgical trials reported both adequately. Adequate recruitment was recorded in 52% (n = 33 of 63) surgical and 55% (n = 33 of 60) nonsurgical trials, with approximately a quarter (n = 17 and n = 16, respectively) of the trials in both the surgical and nonsurgical categories reporting an adequate power calculation.

CONCLUSIONS

There was no evidence that the reported quality of surgical trials was different to nonsurgical trials. However, approximately half or less of all the trials reviewed reported adequate methodology.

Checklists to improve the quality of the orthopaedic literature

Several checklists have been developed in an effort to help journals and researchers improve the quality of reporting in research. The CONSORT statement and the CLEAR NPT evaluate randomized trials. The MOOSE and QUOROM checklists evaluate meta-analyses. The STROBE checklists assists readers in evaluating observational studies and the STARD checklist was developed for diagnostic test evaluation. The checklists presented here provide an invaluable source of guidance to authors, journal editors and readers who are seeking to prepare and evaluate reports. As evidence-based medicine continues to establish itself as the new paradigm by which medicine is practiced, the need for good reporting for all research designs must also become commonplace as opposed to the exception.

An established extracorporeal membrane oxygenation protocol promotes survival in extreme hypothermia

BACKGROUND

Historical reports indicate that active rewarming with extracorporeal membrane oxygenation (ECMO) can salvage a patient after hypothermic cardiac arrest. We created a protocol that includes ECMO for extreme hypothermia to guide rewarming of the hypothermic patient.

METHODS

A retrospective review of the ECMO rewarming protocol (2004-2006) was conducted.

RESULTS

The active rewarming protocol is a flowchart that is available on our hospital intranet and can be accessed in the trauma bay. A severely hypothermic patient triggers the activation of a TRAUMA ONE-OP ECMO response. During the 2-year period, there were 5 activations of the system and 4 children were placed on ECMO. Two of the 4 were dramatically salvaged and eventually discharged neurologically intact. All 5 children were found pulseless at the scene before transport. The average time from the injury occurrence to arrival was 94 minutes (range, 41-181 minutes). Mean cardiopulmonary resuscitation time was 78.2 minutes (range, 37-152 minutes). The mean core temperature on arrival was 25.4 degrees C (range, 20.4 degrees C-28.6 degrees C). The average time from arrival to ECMO cannulation was 25.5 minutes (range, 16-37 minutes).

CONCLUSION

A preemptive strategy for the severely hypothermic patient provides an organized approach and prompt response. Expeditious rewarming can make the difference in an opportunity for survival.

The design and assessment of prospective randomised, controlled trials in orthopaedic surgery

Randomised controlled trials represent the gold standard in the evaluation of outcome of treatment. They are needed because differences between treatment effects have been minimised and observational studies may give a biased estimation of the outcome. However, conducting this kind of trial is challenging. Several methodological issues, including patient or surgeon preference, blinding, surgical standardisation, as well as external validity, have to be addressed in order to lower the risk of bias. Specific tools have been developed in order to take into account the specificity of evaluation of the literature on non-pharmacological intervention. A better knowledge of methodological issues will allow the orthopaedic surgeon to conduct more appropriate studies and to better appraise the limits of his intervention.

Rapid endovascular warming for profound hypothermia

Profound hypothermia is associated with high mortality and morbidity. Optimal outcomes have been reported with invasive extracorporeal warming techniques not readily available in most hospitals. Endovascular warming devices may provide a less invasive alternative. A 68-year-old woman developed profound hypothermia after environmental exposure. On arrival, she was comatose, severely bradycardic, without palpable pulses, and with a core body temperature of 23.0 degrees C (72 degrees F). Attempts to warm her with traditional methods during 2 hours were ineffective. An endovascular temperature control system was placed and effectively warmed the patient at about 3 degrees C (4.5 degrees F) per hour, with return of hemodynamic stability. When hypothermia is profound, surface warming works poorly and invasive strategies, including cardiopulmonary bypass, are recommended. Rapid warming from profound hypothermia can be accomplished with endovascular systems, and these may be an effective alternative to more invasive extracorporeal methods.

Anticoagulation and Pediatric Extracorporeal Membrane Oxygenation: Impact of Activated Clotting Time and Heparin Dose on Survival

BACKGROUND

Anticoagulation during pediatric extracorporeal membrane oxygenation (ECMO) is accomplished by titrating heparin administration to maintain an activated clotting time (ACT) of between 180 and 220 seconds. We hypothesized that an ACT of 180 to 220 seconds results in inadequate anticoagulation during pediatric ECMO and that increased heparin levels will lead to increased survival.

METHODS

A retrospective review was conducted of 604 consecutive pediatric ECMO patients at a single institution between 1980 and 2001. Multiple logistic regressions were used to assess the impact on survival of ACT, heparin, age, weight, diagnosis, and previous surgery.

RESULTS

There were 349 survivors (57.8%), and 255 (42.2%) nonsurvivors. Mean hours on ECMO were 182 +/- 134 (range, 3 to 957 hours), mean ACT was 227 +/- 50 seconds (range, 158 to 620 seconds), and the mean hourly heparin dose was 45 +/- 21 U/kg (range, 6 to 134 U/kg). Regression analysis indicated that increased heparin administration was predictive of survival (p < 0.0001), independent of all other variables. The ACT was not a predictor of survival (p = 0.096). Although previous surgery was independently associated with an increased likelihood of ECMO death (p < 0.001), increased heparin administration again exerted a survival advantage (p = 0.012).

CONCLUSIONS

Adherence to the recommended ACT of 180 to 220 seconds in pediatric ECMO patients may result in inadequate anticoagulation. Survival is improved by increased heparin administration independent of the ACT. The ACT may be too insensitive to maintain adequate long-term systematic anticoagulation, and other methods, such as heparin levels or functional parameters such as anti-Factor Xa activity or thrombin generation, should be investigated.

Standards of reporting of randomized controlled trials in general surgery: can we do better?

OBJECTIVE

To evaluate the quality of reporting of surgical randomized controlled trials published in surgical and general medical journals using Jadad score, allocation concealment, and adherence to CONSORT guidelines and to identify factors associated with good quality.

SUMMARY BACKGROUND DATA

Randomized controlled trials (RCTs) provide the best evidence about the relative effectiveness of different interventions. Improper methodology and reporting of RCTs can lead to erroneous conclusions about treatment effects, which may mislead decision-making in health care at all levels.

METHODS

Information was obtained on RCTs published in 6 general surgical and 4 general medical journals in the year 2003. The quality of reporting of RCTs was assessed under masked conditions using allocation concealment, Jadad score, and a CONSORT checklist devised for the purpose.

RESULTS

Of the 69 RCTs analyzed, only 37.7% had a Jadad score of > or =3, and only 13% of the trials clearly explained allocation concealment. The modified CONSORT score of surgical trials reported in medical journals was significantly higher than those reported in surgical journals (Mann-Whitney U test, P < 0.001). Overall, the modified CONSORT score was higher in studies with higher author numbers (P = 0.03), multicenter studies (P = 0.002), and studies with a declared funding source (P = 0.022).

CONCLUSION

The overall quality of reporting of surgical RCTs was suboptimal. There is a need for improving awareness of the CONSORT statement among authors, reviewers, and editors of surgical journals and better quality control measures for trial reporting and methodology.

Surgical treatment of coronary multivessel disease

Coronary artery bypass grafting has had a significant impact on the treatment of angina, and has been the 'gold standard' since 1969. Its use and efficacy has been increased by revascularization in cardiac arrest and the use of the internal mammary artery. In parallel, catheter techniques have evolved by means of balloon dilatation and additional stenting. This has effected the referral to surgery despite the development of new arterialization techniques and minimally invasive surgery. As competing techniques, an acceptable equilibrium between surgery and stenting will be found within the next years.

[Resuscitation from accidental hypothermia of 22 degrees C with circulatory arrest: importance of prehospital management]

In winter, French Medicalised Ambulance Service rescued a 50-year-old patient after suicide attempts by jump from a bridge in the Seine. The body was discovered after more than 10 minutes of immersion. She was unconscious and in deep hypothermia with circulatory arrest. Basic CPR was started immediately and oral intubation and 100% oxygen ventilation was performed. Ventricular fibrillation appeared but repeated defibrillation failed due to profound hypothermia (rectal temperature: 28 degrees C). The patient was immediately transported to hospital. CPR and mechanical ventilation was continued during transport. The patient was taken in emergency room. The oesophageal temperature was 22 degrees C. Rewarming using extracorporeal circulation was immediately initiated after insertion of femoral access. At 27 degrees C, ventricular fibrillation started and was converted by external defibrillation to a pulse-generating cardiac rhythm. At 360 minutes, the patient's rectal temperature had reached 36 degrees C and she was disconnected from cardiopulmonary bypass with inotropic support. She was transferred to the intensive care unit after 9 hours of resuscitation, rewarming and stabilisation. Mechanical ventilation was needed for 15 days because of adult respiratory distress syndrome. Renal failure, pneumonia also occurred. She was successfully extubated on day 15 and was discharged from intensive care unit on day 21, suffering no neurological side effects.

Accidental Hypothermia

Hypothermia is a multi-system disorder that significantly increases morbidity and mortality in the injured patient. It is an environmental hazard that can kill in its own right. The most difficult differentiation and management decisions are likely to be with victims in Stage II or Stage III hypothermia. Following successful rescue in these cases, arresting any further cooling of the core temperature, instituting rewarming strategies and careful patient handling will be the key factors in reducing morbidity and mortality.

Coronary endarterectomy in the current era

PURPOSE OF REVIEW

The increasing incidence of diffuse coronary artery disease in the current era challenges cardiac surgeons in accomplishing their goal of complete revascularisation. Although coronary endarterectomy is used with encouraging results in most institutions, there remains some controversy in its indications, technique, and results. The purpose of this review is to highlight the important evolutions of technique in the recent past.

RECENT FINDINGS

Despite the increased risk factors and comorbidities in patients presenting with diffuse coronary artery disease requiring coronary endarterectomy, the results of coronary endarterectomy are improving inline with the improvements in the results of conventional coronary artery bypass grafting surgery. The improving results of coronary endarterectomy in the left anterior descending artery are further clarified. The intra- and postoperative use of prostacyclin has been shown to be effective in reducing mortality and perioperative myocardial infarction. The technique of open coronary endarterectomy with on-lay patch bypass grafting has been shown to be safe and effective in reducing mortality and improving patency as compared with the closed (traction) method of coronary endarterectomy. The use of coronary endarterectomy was also found to be effective in the treatment of in-stent restenosis in the setting of diffuse coronary artery disease. The results of off-pump coronary endarterectomy are encouraging and comparable with the conventional coronary endarterectomy using cardiopulmonary bypass.

SUMMARY

With the increasing incidence of diffuse coronary artery disease and improving results of coronary endarterectomy, it is vital for cardiac surgeons to have coronary endarterectomy in their armamentarium to achieve complete coronary revascularisation.