Home / Essay / Pulsatile vs. Nonpulsatile Perfusion, Essay Example

Pulsatile vs. Nonpulsatile Perfusion, Essay Example

Pages: 8

Words: 2307

Abstract

Background

Various studies have been published that showcase the benefits of using pulsatile perfusion techniques in cardiovascular surgeries for post-operative recovery and overall improvements in patient health. A lack of technological advancements and availabilities have hindered clinicians’ use of such techniques, as well as limited experience that clinicians have with such techniques in the surgical environment.

Objective

To examine the literature published on studies that meet the inclusion criteria and showcase positive or negative consequences of using pulsatile perfusion techniques as compared to non-pulsatile perfusion techniques.

Research-Type Review

The types of research that are available on this topic are very limited, which also calls for reasoning behind the problems associated with clinical use of pulsatile perfusion techniques. We examine the available research and show evidence as to what can be included and how it supports or contradicts our hypothesis.

Literature Review

Nine studies have been evaluated based on the inclusion criteria. The researchers examine the areas of mortality, myocardial infarction, renal function, neurological injury, and inflammatory responses. We have also devised a table that showcases the available research and what positive or negative consequences are explained throughout the research for pulsatile and non-pulsatile perfusion techniques. Substantial evidence exists in the publication of literature that promotes the use of pulsatile perfusion techniques by clinicians and subjects readers to the benefits of such techniques as opposed to non-pulsatile perfusion during surgeries.

Conclusion

Our review of the available literature promotes the use of pulsatile perfusion techniques and advanced availability of technology and research for clinicians to utilize these techniques in surgical environments.

Background

Pulsatile perfusion has been clinically proven to provide significant advantages to the body over any non-pulsatile perfusion techniques that are currently available. Unfortunately, clinicians often tend not to use pulsatile perfusion to offer heart treatment during surgeries because of a limited amount of technology that is available for clinicians to use in the operating room. Much literature has been provided to show the benefits of pulsatile perfusion techniques on recuperation and recovery during and after surgery. In addition to a lack of readily-available technology for pulsatile perfusion, clinicians also maintain that there is an inadequate clinical experience that is available to examine and analyze routing use of pulsatile perfusion techniques. Studies have also shown that non-pulsatile perfusion is associated with an increase in peripheral vascular resistance (PVR) that occurs during the perfusion period and that pulsatile perfusion is accompanied by significantly lower PVR levels. In order to properly establish a regular use of pulsatile perfusion techniques, clinicians and researchers must examine the need for pulsatile perfusion as compared to non-pulsatile perfusion techniques, and then analyze the need and potential benefits of using the techniques in the operating room.

Objective

We examined multiple research sources in order to better understand up-to-date findings on pulsatile perfusion studies and the clinical importance of these techniques as they compare to non-pulsatile perfusion techniques. This research holds clinical importance drawing a comparison between the beneficial areas of mortality, myocardial infarction, renal function, neurological injury, and inflammatory responses.

Research & Literature

Numerous articles and research studies have been performed to analyze the negative and positive impacts of pulsatile perfusion techniques on recovery outcomes during cardiovascular surgeries. As shown in Figure 1, there were only 126 articles published between 1982-2005 on the topics of pulsatile and non-pulsatile perfusion techniques. Of these 126 articles, 52 were based on animal trials, 28 were based on pediatric studies, and 12 compared adults to pediatric studies. In all, only nine articles met the inclusion criteria for our literature review. This further supports the claims by clinicians that a shortage of available research exists and makes it very difficult for clinicians to use pulsatile perfusion techniques without verifiable research to help support its use in the surgical environment.

Literature Review

Table 1 provides a breakdown of the research that is available for inclusion into this analysis. Each outcome has clinical research that supports the findings that there were improvements with the pulsatile perfusion flow. However, mortality, renal injury, and neurological injury outcomes varied within the research and literature and showed instances where there were no significant differences between pulsatile flow and non-pulsatile flow results.

Mortality

Studies have shown that mortality is not impacted by the use of pulsatile perfusion techniques over non-pulsatile techniques. In fact, research has demonstrated that cardiovascular morbidity and mortality have not been affected by pH management or pulsatile perfusion techniques. This leads us to assume that mortality is neither limited nor benefited by the use of pulsatile perfusion techniques, and information should be further analyzed by clinicians to support the use of such techniques. Evidence-based perfusion techniques must continue to be utilized in order to ascertain a direct correlation between the improved mortality rates suggested within this literature and the actually medical methods used during surgery.

In a separate study, researchers found that total mortality was significantly lower in the pulsatile group (4.6%, p = 0.018) compared with the non-pulsatile group (10.3%, p= 0.06). This further suggests that pulsatile perfusion techniques are much more beneficial to decreasing overall mortality rates than non-pulsatile techniques. Still, much more research is necessary to prove to clinicians that the techniques are overall beneficial, and this suggests the inclusion of much more studies into current-day research. Overall, however, literary evidence has shown that pulsatile perfusion techniques improve coronary flow, and that mortality is not negatively impacted through the use of such techniques.

Myocardial Infarction

Similar research to decreased mortality rates have also been shown to suggest decreased rates of myocardiac infarction in patients where pulsatile perfusion techniques were utilized. In a recent study by researchers the effects of pulsatile perfusion techniques were compared to those of non-pulsatile perfusion techniques within human patients that had undergone cardiopulmonary bypass surgery. Research suggested that the incidence of myocardial infarction was 5.7% (p = 0.04) in the nonpulsatile group and 0.6% (p =0.01) in the pulsatile group [1]. Many clinical studies have also shown highly improved myocardial function after pulsatile perfusion as compared to non-pulsatile perfusion techniques [1]. In addition to a reduction in myocardial infarction with pulsatile perfusion, research also shows lower levels of thromboxane and increased concentrations of prostacyclin, which are changes that are typically favoring faster and more efficient blood flow throughout the body. Additionally, research results showed an increase in myocardial oxygen and improved subendocardial blood flow with pulsatile perfusion over non-pulsatile perfusion. Overall, the benefits of pulsatile perfusion techniques within cardiopulmonary bypass surgery are very clear and suggest that clinicians continue to strive to utilize these techniques in order to increase blood flow and decrease the risk of myocardiac infarction within treated patients.

Renal Function

Patients with chronic renal failure and chronic obstructive pulmonary disease have an increased risk of fatal outcome, increased length of hospital stay and increased incidence of organ failure and morbidity after open heart surgery [6]. Research covering the effects of pulsatile perfusion techniques varies in the areas of renal function. As shown in Table 1, evidence has been shown to suggest that pulsatile perfusion techniques aid in decreasing renal injuries and dysfunction, while providing no significant differences between the two techniques. There appears to be a slight discrepancy in the research within the belief that pulsatile perfusion techniques are more beneficial than non-pulsatile techniques. Rater, two studies have shown results that suggest that non-pulsaitle persfusion techniques are equally beneficial in reducing renal injury. The two studies maintained that the impacts of pulsatile and nonpulsatile perfusion techniques had no difference in the renal failure index between multiple groups. Therefore, clinicians should feel free to utilize either technique when considering solely the negative or positive consequences associated with pulsatile perfusion.

On the other hand, Kocakulak et al. suggested that although nonpulsatile perfusion during cardiopulmonary bypass is used more expansively than pulsatile perfusion, it causes dysfunction of many systems, especially the renal system. The evidence in literature suggest that pulsatile perfusion techniques are much more beneficial because they reduce the risk of renal injury and decreased renal dysfunction caused by cardiopulmonary bypass. Despite the evidence, differing opinions suggest that more research must be conducted to clearly establish a positive or negative relationship between the two opposing techniques.

Neurological Injury

Evidence varied upon the literature results of comparing pulsatile and non-pulsatile treatment techniques as each reduced the chance for neurological injury. Takahara et al. suggested that there was a substantial difference between the two techniques in showing marked improvements for reducing the risk of neurological injury. However, two separate cases, showed in Table 1, argued that there were no differences between the results of the treatment techniques. However, it is important to note that the authors of these two cases continued to argue for the use of pulsatile treatment methods despite showing no difference between the methods for reducing or eliminating neurological injury.

Inflammatory Responses

The inflammatory responses demonstrate only signs of improvement and decrease in inflammation with pulsatile perfusion techniques. In our literature review, no evidence was found to support that non-pulsatile perfusion is superior or equal to that of perfusion techniques. One study in particular performed by Driessen et al. suggested that the cause of inflammation throughout the body is actually from a decrease in blood flow. As the flow of the blood is decreased, so is the flow of oxygen to tissues that require it to function correctly. Therefore, the body engages in a protective action to inflame the tissue in order to protect it from additional damage. This process can be attributed to the use of nonpulsatile perfusion techniques during cardiopulmonary bypass surgey. As previously stated, nonpulsatile perfusion techniques actually decrease the amount of blood flow throughout the body. Evidence shows that the academic community is unanimous in showing that inflammatory response is decreased with pulsatile perfusion techniques.

Discussion

In our literature review, the evidence for pulsatile perfusion techniques is very clear. Positive consequences will result in clinical trials through the use of such techniques during cardiopulmonary bypass surgery. Not only will pulsatile perfusion techniques increase blood flow, they decrease mortality rates, myocardiac infarction and renal injury or dysfunction. Research is unanimous in stating solely positive benefits of pulsatile perfusion during these types of surgeries. However, the original problems still remain that make it difficult for clinicians to not only support the research but utilize the techniques within their surgical environments for treatment.

First of all, clinicians argue that there is very little evidence that meets the inclusion criteria that would suggest that clinicians should really utilize pulsatile perfusion in the operating room. Despite the large array of research that suggests positive results, only nine studies actually met the inclusion criteria. It is highly unlikely that a clinician would utilize a technique without having hard evidence to support it. Figure 1 shows the breakdown of the available literature dating as far back as 1982. Most of the trials have been performed on children or animals. Very little research has been performed on adults, which are the largest medical population that would be receiving cardiopulmonary bypass surgery.

Furthermore, clinicians often lack the availability of technology to perform such techniques. The cost of the technology is often a profound reason why it is not utilized within a healthcare setting and unfamiliarity of the techniques. Despite this argument, it is clear that evidence-based pulsatile perfusion techniques must be used in further trials and within the medial environment to separate results between the two techniques and improve upon the recovery problems currently associated with non-pulsatile techniques. As the medical community continues to advance in their understanding and usage of pulsatile perfusion techniques during surgery, the patient outcomes will continue to increase and will put an end to the dissenting views between the two treatment methods.

Conclusion

The benefits of pulsatile perfusion techniques are very strong in supporting additional research and using evidence-based pulsatile perfusion techniques. These techniques will greatly benefit the patients and reduce the risk of additional post-operative complications. It is the responsibility of the academic and medical communities to engage in activities that help educate, train and conduct additional research to support these techniques and probably make it a new standard of care.

References

Murkin JM, Martzke JS, Buchan AM, Bentley C, and Wong CJ; The Journal of Thoracic and Cardiovascular Surgery, A randomized study of the influence of perfusion technique and pH management strategy in 316 patients undergoing coronary artery bypass surgery, vol. 110, issue 2, December 1994

Driessen JJ, Dhaese H, Fransen G, Verrelst P, Rondelez L, Gevaert L, van Becelaere M, and Schelstraete E; Perfusion, Pulsatile compared with nonpulsatile perfusion using a centrifugal pump for cardiopulmonary bypass during coronary artery bypass grafting. Effects on systemic haemodynamics, oxygenation, and inflammatory response parameters, vol. 10, 1995

Taylor KM, Bain WH, Davidson KG and Turner MA; Thorax, Comparative clinical study of pulsatile and non-pulsatile perfusion in 350 consecutive patients, vol. 37, 1982

Sezai A, Shiono M, Nakata K, Hata M, Iida M, Saito A, Hattori T, Wakui S, Soeda M, Taoka M, Umeda T, Negishi N, and Sezai Y; Artificial Organs, Effects of pulsatile CPB on interleukin-8 and enthothelin-1 levels, vol. 29, issue 9, 2005

Badner NH, Murkin JM, and Lok P; Anesth Analg, Differences in pH management and pulsatile/nonpulsatile perfusion during cardiopulmonary bypass do not influence renal function, vol. 75, 1992

Kocakulak M, Askin G, Kucukaksu S, Tarcan O, and Piskin E; Blood Purification, Pulsatile flow improves renal function in high-risk cardiac operations, vol. 23, 2005

Henze T, Stephan H, and Sonntag H; Thorac. Cardiovasc. Surgn, Cerebral dysfunction following extracorporeal circulation for aortocoronary bypass surgery: no differences in neuropsychological outcome after pulsatile versus nonpulsatile flow, vol. 38, 1990

Takahara Y, Sudo Y, Nakano H, Sato T, Ishikawa H, and Nakajima N; Thorac. Cardiovasc. Surgn., Strategy for reduction of stroke incidence in coronary bypass patients with cerebral lesions. Early results and mid-term morbidity using pulsatile perfusion, vol. 48, issue 9, Sept. 2000