Guidelines for perioperative haemodynamic optimization

16 Julio 2015

Guías de consenso de la Sociedad Francesa de Anestesia y Reanimación. Podéis descargarla (en francés) haciendo click en el enlace.

Guidelines for perioperative haemodynamic optimization

Comentarios a Impact of mechanical bowel preparation on survival after colonic cancer resection ( Br J Surg 2014: 101: 1594–1600)

25 Junio 2015

Impact of mechanical bowel preparation on survival after colonic cancer resection – Å. Collin1, B. Jung, E. Nilsson, L. Påhlman1 and J. Folkesson (+ Renehan)

Por Mihai Paduraru

This is a clearly presented paper with specific intention and methodology. The authors identify where there are limitations in their research and suggest how this can be improved upon. However, as has already been identified by A. G. Renehan in his commentary in BJS (2014), a key flaw in the validity of the findings of Jung et al, is the lack of attention paid to the impact of confounding factors over a ten year period, the fact being that the first trial was rigorous as an RCT, with different aims, and the second study is retrospectively analyzing data using the same patient group from the original trial, can lead to confusion. He suggests that the statistical methodology used was insufficient in some cases and lacking in others to support the findings and therefore, the conclusion. Renehan has already commented (BJS 2014) on the insufficiency of some of the statistical analysis and lack of attention to confounding factors.

There are some further points to make in addition to Renehan’s comments. Firstly the high number/proportion of patients from the RCT that were excluded from the data analysis of this second study. The authors give a rationale for this but the end result is a smaller sample size than is considered valid for the results to be significant. Since this is a retrospective cohort study, this is an important point. If all patients had been included, then it has to be considered that the results might have been different. One of the reasons stated for the exclusion of certain patient data was the lack of accuracy of the data base used and the inconsistency of recording, compounded by the changes in reporting over the 10 year period. Again, this factor cannot be ignored and throws into question the accuracy of the patient case records.

Secondly, the higher proportion of patents in the non MBP group with stage III tumor is not discussed sufficiently. The difference between stage II and III is that the cancer has spread to nearby lymph nodes in the latter stage. The expectation then would be for this group to have a lower cancer specific survival rate. Furthermore, each stage has sub classifications (a,b and a,b,c respectively) and we do not know, from the paper, if the stages are pre- or postoperative, nor if the study takes into account the number of nodes in relation to the long term oncological results for stage III (stage IV being excluded). The authors do not provide any data as a reference with regard to overall colon cancer survival for patients undergoing resection with type II and type III tumor stage.

Thirdly, the ‘surgeon factor’ is not discussed at all as a factor. The proficiency of the surgeon has been demonstrated in other studies to play an important role in trial outcomes. This could be another confounding factor, especially with regard to practice 10 years ago and with the debate to prepare mechanicaly or not the colon.

Another confounding factor not accounted for and already mentioned by Renehan, are other/additional kinds of oncological treatment – adjuvance.

In agreement with Renehan, the study has some use in generating further research, but these new studies need to be more thorough in identifying and accounting for the confounding factors.

Overall this paper contributes no hard evidence that MBP could improve colon cancer survival rates, with a low level of evidence for the moment and with high level of bias.

On the other hand, if this study had been a strong one, with a high level of evidence and recommendation (Harbour and Miller), to give it validity, what would the implications for practice be: To choose the option of reducing postoperative complications, including mortality, by not undertaking MBP (as recommended and proven by ERAS); or to choose long term better oncological results re-instating the classical MBP for colon resections? Such a recommendation poses a real ethical dilemma and needs much more concrete evidence than this study offers before we take a step back to the future.

Lectura Crítica – “Introducing an enhanced recovery after surgery program in colorectal surgery: A single center experience”

22 Junio 2015

Lectura crítica a “Introducing an enhanced recovery after surgery program in colorectal surgery: A single center experience” Stefano Bona, Mattia Molteni, Riccardo Rosati, Ugo Elmore, Pietro Bagnoli, Roberta Monzani, Monica Caravaca, Marco Montorsi, Department of General Surgery, University of Milan School of Medicine, Humanitas Research Hospital, 20089 Rozzano, Milan, Italy

By Mihai Paduraru. PhD, MSc, MD – Servicio de Cirurgia General y Digestiva. Hospital General de Tomelloso. España.

The article defines itself as a ‘prospective single center cohort study’ and therefore has been evaluated against the criteria set out in the CASP Cohort Study Checklist (2013).
The title of this paper highlights some of the ambiguity in the focus of this study. It implies a reflection on the experience that took place rather than a more solid scientific approach. The authors do give an aim to the study: ‘…the prospective evaluation of an ERAS protocol that includes full application of all ERAS principles, through the progressive steps of its implementation at our Institution, (… from “pilot study” to “standard of care”)’.
It is clear with regard to the population to be studied and the outcomes to be measured: length of postoperative hospital stay, re-admission rate, compliance to the (ERAS) protocol and morbidity by comparing results from the pilot and ‘shared’ phases of the implementation, thus with the aim of highlighting the benefits and issues incurred.

The rationale for the study is explicitly stated in that, despite there being a large body of evidence to support the implementation of ERAS, there is still a reluctance in practice to implement due to such cultural factors as fear of change structurally/organizationally.(‘The question seems no longer to be whether colorectal surgery according to “enhanced recovery after surgery” (ERAS) principles or to traditional care is better, but rather how to improve the approach and facilitate its deployment.’) Much of the detailed background to the study is found in the ‘Discussion’ and would be better for the paper’s structure for it to be in the ‘Introduction’.

The ‘recruitment’ of the cohort is implied from the ‘inclusion criteria’ that all patients over the age of 18 undergoing elective colorectal laparoscopic resection surgery and who consented to take part (‘and judged able to understand the requirements of the study’), were involved in the trial. It is not clear or explained what is meant by: ‘judged able to understand the requirements of the study’; how objectively this was achieved and what patients were indeed told; neither is it clear how many patients were excluded as a result of this (or as a result of the other stated ‘exclusion’ criteria), therefore it is not possible to accurately assess whether the recruitment methods were wholly acceptable or if the population studied was representative of that as a whole. The authors state that traditionally their hospital performs 300 colorectal resections annually (the majority of which are via laparoscopy), however, only data from 190 patients is used in the study, with no explanation as to why there is a difference in these numbers.
The inclusion criteria, when extended beyond the pilot group, are also extended (to include ASA score of V and some emergency cases). Again, no rationale is given for this but these new factors prohibit a direct comparison with the pilot group and make it difficult to measure the accuracy of the results against the outcomes set. The lack of clarity in these issues opens the study up to selection bias and questions its validity.

The methodology of the study lacks some rigor. All patients were exposed to the same procedures as specified by ERAS and were therefore objective; however, where there was no compliance to the protocol, these factors were not measured in relation to the outcomes. Since both groups were not identical from both the patient profile and the experience/practice of the medical personnel point of view, the measurement of the outcomes cannot be strictly accurate. The issue of the pilot phase being conducted in a ‘specialist’ unit with (and ‘due to’) dedicated staff with sympathetic training (e.g. Nurses experienced and focused on ‘fast tracking’ a patient), is an important factor – closer to clinical trial conditions. The authors discuss these but do not account for them as confounding factors statistically, thus the results are open to bias.
The trail is not consistent in the period of exposure between the two groups (21 months in the pilot study and 7 months for wider implementation), but the significance of this is not discussed. The authors compare results between the two groups in terms of outcomes re: recovery rates and readmissions, presumably with the view of illustrating the benefits and consequences of compliance/non compliance with ERAS. It is possible to argue that the pilot needs longer to implement and once established, could be easier to introduce to the rest of the hospital. Conversely, taking into account the number of staff in the rest of the center and the training required for effective implementation, the second period should have been longer than the first. Indeed, it could be argued that if this part of the study had been longer, then overall results might have been better due to compliance though better understanding and practice. Follow up was undertaken at 7 days and then 1 month, which is standard procedure and is deemed sufficient.
Statistical analysis of the results is not rigorous and there is no description of how results were obtained or which tests were used to analyze the results. There are no tables depicting the breakdown of results or the differences between patients, treatment and personnel. Only 3 graphical representations are offered and these are not easy to interpret. The authors use mean and median data in the text but only median on the graphs, leading to initial confusion. Differences in stated outcomes are expressed in terms of percentages but are not given P values to identify any statistically significance and Confidence Intervals are not set in order to establish the validity of the results. Poorer results are associated with non compliance but are not strictly analyzed for this, indeed the authors state that their results ‘seem’ to fit this hypothesis but provide no strong evidence.

Other than precise detail of the ERAS protocols applied, the authors do not systematically detail how implementation from ‘pilot’ to ‘system wide’ application was planned and undertaken; nor how staff were trained; nor of all the precise difficulties encountered during implementation and why some aspects of the protocol were harder to implement than others. All these aspects surely would be of benefit to the clinical community, especially since implementation is a focus of the trial. This study does not adequately expose these issues nor give any attempt to guide future trials with the limitations/achievements of their study, despite the ‘Primary Endpoint being: ‘… the description of the results and the identification of critical issues of large scale implementation of an ERAS program in colorectal surgery emerged in the experience of a single center’. The Secondary Endpoint is: ‘…the identification of interventions that have been proven to be effective for facilitating the transition from traditional care pathways to a multimodal management protocol according to ERAS principles in colorectal surgery at a single center.’ They only give some examples in the discussion, such as dedicated space being provided for better mobilization of patients.

The study gives results of pre ERAS procedures and compares these with those after implementation, as well as comparative data between pilot, second and third stage implementation. ERAS has already been proven effective in trials and the results of this study show that ERAS is more effective in the pilot stage but still reduces length of hospitalization (mean 8 days from 10). Statistical comparisons for morbidity and readmission are given for the 3 stages but not for the period before ERAS implementation and so consistent comparisons cannot be made. Again, the lack of tabulated data makes these results harder to find.

The authors claim: ‘Our results confirm that introduction of an ERAS protocol for colorectal surgery allows quicker postoperative recovery and shortens the length of stay compared to historical series.’ But this claim is weakened because the purpose of the study is confusing: evidence is provided for the validity of ERAS but is not consistent; the comparison of pilot study results against wider implementation, show that a controlled environment is more effective and yet the pilot is not strictly comparable as it varies in key aspects from the wider study; the pilot is also used to serve as an incentive for this wider implementation and to provide evidence for the benefits of full implementation, the authors are not rigorous enough however in detailing the implementation methods to enable other hospitals to benefit from these.

The authors cite 2 other studies already identifying that there is decreased compliance to protocols when undertaking wide scale application and the results from this study demonstrate the same, and argues for compliance in order to reduce morbidity based on some, (not rigorous) evidence of a correlation between the two. This is useful information for further investigation.

The study provides no new evidence but does serve to demonstrate that, firstly a centre has adopted ERAS protocols as its standard practice, and secondly, even though there is not total compliance and therefore results show less positive outcomes overall in comparison to those of a designated pilot group of patients, they are better than those achieved without application of ERAS, thus dismissing some of the arguments against wide scale implementation.”

Comentario sobre el Trabajo de keller DS et al ( J Am Coll Surg. 2014 Dec; 219(6):1143-8)

23 Diciembre 2014

Comentario a: “Demonstrating the Benefits of Transversus Abdominis Plane Blocks on Patient Outcomes in Laparoscopic Colorectal Surgery: Review of 200 Consecutive Cases”. Keller DS, Ermlich BO, Delaney CP. J Am Coll Surg. 2014 Dec; 219(6):1143-8.

Ha pasado más de una década desde que en 2001, Rafi (Anaesthesia. 2001;56(10):1024-6) describió la técnica de anestesia regional de la pared abdominal basada en el bloqueo de los nervios intercostales a nivel del plano del músculo transverso del abdomen. Era una técnica no exenta de riesgo, ya que el acceso al nivel del plano fascial entre los músculos transverso y oblicuo externo se realizaba por técnica de pérdida de resistencia al atravesar la fascia del oblicuo interno. El riesgo de punción peritoneal era elevado al tratarse de una técnica “a ciegas”.
Con la introducción de la ecografía en la práctica anestésica, el riesgo de complicaciones derivadas de la técnica se ha minimizado. La visualización de las estructuras anatómicas permite la localización precisa del plano donde debe inyectarse el anestésico local para alcanzar su diana. Otra de las variaciones en la técnica descrita por Rafi ha sido el lugar de de punción. Inicialmente el autor accedió al plano transverso desde el triangulo de Petit, ya que desde este punto el acceso al plano evitaba el oblicuo externo haciendo más fácil el abordaje. Sin embargo, con esta técnica solamente se lograba la anestesia de la región infraumbilical de la pared abdominal, siendo ineficaz para cirugías supraumbilicales. Con el estudio de la distribución metamérica de la inervación de la pared abdominal, se han descrito nuevos accesos. Entre ellos está el acceso subcostal, con el que se logra una analgesia supra e infraumbilical de la abdominal. En esta región, a diferencia de zonas más inferiores, el músculo recto del abdomen descansa sobre el transverso, lo que deberá tenerse en cuenta en este bloqueo.
La tendencia actual es la realizar el bloqueo transverso en la línea arcuata, zona en la que los nervios intercostales atraviesan la región fascial para distribuirse por debajo del recto del abdomen formando un verdadero plexo nervioso. En la zona subcostal el sitio de elección de depósito del anestésico será entre el transverso y el recto, con lo cual se loga minimizar el riesgo de punción peritoneal. A este nivel se consigue una anestesia eficaz de los últimos cinco nervios intercostales de T7 a T11.
En la literatura existen números referencias de la eficacia del bloqueo del plano transverso en cirugía abdominal. Sin embargo, las referencias en cirugía laparoscópica no son tantas.
Por lo dicho hasta el momento, sorprende encontrarse en la literatura referencias que abogan por técnicas no ecográficas para el abordaje del plano transverso. En el presente artículo el abordaje se realiza bajo visión laparoscópica directa y utilizando técnicas de punción a ciegas con el uso de los cásicos “pops”, que tan fielmente son descritos por los autores, y que en la literatura no han demostrado su eficacia. Ya que la mayoría de las veces la punción de la fascia muscular no llega a percibirse, con el consiguiente riesgo de punción peritoneal. También sorprende el lugar donde los autores realizan la punción; en la línea media axilar, en el punto medio entre la cresta iliaca y el margen costal. A ese nivel, la variabilidad de los músculos atravesados no asegura la localización del plano transverso con la técnica de los “pops”. Por otro lado, solamente el uso de grande volúmenes de anestésico podría asegurar, si el lugar de infiltración es el adecuado, un nivel de anestesia eficaz.En este artículo, el bloqueo se realiza con lo trocares e incisiones ya realizados, con lo que el concepto de analgesia preventiva no se realiza.
La justificación de la técnica podría adecuarse a un hospital donde el servicio de anestesia no estuviera familiarizado con la realización de técnicas eco-guiadas del plano transverso.
Pocas conclusiones podemos sacar de un trabajo retrospectivo con los riesgos de sesgo estadístico que ello supone. Haciendo suyas estas limitaciones y con una muestra de 200 pacientes, los autores concluyen lo ya evidenciado en la literatura, una mejor analgesia postoperatoria, bajo índice de complicaciones y una menor estancia hospitalaria. En resumen, ninguna aportación novedosa.

Javier Longas. Servicio de Anestesia. HCU “Lozano Blesa”. Zaragoza

Bibliografia “seleccionada” Diciembre 2014

18 Diciembre 2014

Con una búsqueda rápida, aparecen más de 25 nuevas publicaciones sobre rehabilitación multimodal y “fast track”. Hemos seleccionado las que nos han parecido más interesantes, y en breve publicaremos nuestra opinión “experta” sobre alguna(s) de ellas.

Keller DS, Ermlich BO, Delaney CP. Demonstrating the benefits of transversus abdominis plane blocks on patient outcomes in laparoscopic colorectal surgery: review of 200 consecutive cases. ACS. 2014 Dec;219(6):1143–8.

Bagnall NM, Malietzis G, Kennedy RH, Athanasiou T, Faiz O, Darzi A. A systematic review of enhanced recovery care after colorectal surgery in elderly patients. Colorect Dis. 2014 Dec;16(12):947–56.

Ament SMC, Gillissen F, Moser A, Maessen JMC, Dirksen CD, Meyenfeldt von MF, et al. Identification of promising strategies to sustain improvements in hospital practice: a qualitative case study. BMC Health Serv Res. 2014 Dec;14(1):641.

Segelman J, Nygren J. Evidence or eminence in abdominal surgery: Recent improvements in perioperative care. WJG. 2014 Nov;20(44):16615–9.

Hughes MJ, Ventham NT, McNally S, Harrison E, Wigmore S. Analgesia After Open Abdominal Surgery in the Setting of Enhanced Recovery Surgery: A Systematic Review and Meta-analysis. JAMA Surg. 2014 Dec;149(12):1224–30.

Cannesson M, Kain ZN. The role of perioperative goal-directed therapy in the era of enhanced recovery after surgery and perioperative surgical home. Journal of Cardiothoracic and Vascular Anesthesia. 2014 Dec;28(6):1633–4.

Nelson G, Kalogera E, Dowdy SC. Enhanced recovery pathways in gynecologic oncology. Gynecol Oncol. 2014 Dec;135(3):586–94.

Chaudhary A, Barreto SG, Talole SD, Singh A, Perwaiz A, Singh T. Early Discharge After Pancreatoduodenectomy: What Helps and What Prevents? Pancreas. 2014 Dec.

Colquhoun DA, Roche AM. Oesophageal Doppler cardiac output monitoring: A longstanding tool with evolving indications and applications. Best Practice & Research Clinical Anaesthesiology. 2014 Dec;28(4):353–62.