Epidurals, DVTs, and chemical prophylaxis in the setting of oncologic surgery

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One discussion this week involved preoperative epidurals and chemical prophylaxis.

Reference: Manguso N, et al. The impact of epidural analgesia on the rate of thromboembolism without chemical thromboprophylaxis in major oncologic surgery. The American Surgeon. 2018 Jun 1;84(6):851-855.

Summary: General surgery patients are at a particularly high risk of developing deep vein thrombosis (DVT) without prophylaxis and some data suggest their risk increases 2-fold if an underlying malignancy is present. A meta-analysis by Leonardi et al (2007) found that without chemical prophylaxis, the rate of DVT is as high as 35%, which drops to 12% if a patient receives chemical prophylaxis.

Although the use of chemical prophylaxis to reduce the risk of thromboembolic events has been validated in numerous studies, these drugs increase the risk of bleeding. Risk of bleeding in the setting of epidural analgesia may put the patient at risk for the potentially catastrophic complication of epidural hematoma which may lead to long-term paralysis.

Manguso et al (2018) evaluated the rate of thromboembolic events in cancer patients undergoing major oncologic abdominal and/or pelvic surgery who had a preoperative epidural catheter (EC) placed for postoperative pain control.

The aim of this study was to evaluate the need for chemical thromboprophylaxis in patients undergoing major abdominal or pelvic oncologic surgery with preoperative EC placement for postoperative pain control. Of the 285 patients for whom data were collected over this five-year period, the rates of above knee and below-knee DVTs were 3.2 and 5.2%, respectively. These patients were all asymptomatic and had no serious adverse events occur secondary to the identified thromboses.

A secondary finding was that 2.5% of patients had above-knee DVT before undergoing surgery; thus, it is important to consider the patient’s risk factors for DVT and screen preoperatively if there is concern.

Our data suggest that patients undergoing major open operations with epidural analgesia have low rates of DVT and may obviate the need for chemical prophylaxis. However, larger studies are required to determine the overall effects of epidural analgesia on the development of DVTs postoperatively.

Will there be positive neurological outcomes after ECMO resuscitation?

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One discussion this week involved neurological outcomes following ECMO resuscitation.

Reference: Ryu JA, et al. Predictors of neurological outcomes after successful extracorporeal cardiopulmonary resuscitation. BMC Anesthesiology. 2015 Mar 8;15:26. doi: 10.1186/s12871-015-0002-3

Summary: Extracorporeal membrane oxygenation (ECMO) is a useful intervention for refractory cardiogenic shock and respiratory failure. Because ECMO implementation can rapidly normalize circulation in patients under cardiac arrest, it has been used to assist cardiopulmonary resuscitation (CPR). Using traditional chest compression is less effective than using ECMO with CPR (known as extracorporeal CPR or ECPR). ECPR can achieve more effective recovery of spontaneous circulation (ROSC) than conventional CPR.

Since the brain is the organ most vulnerable to hypoxia and inadequate perfusion, ECPR can result in severe neurologic deficits if ECMO is not performed promptly. In addition to delay, several factors may lead to poor neurological outcomes after ECPR. Achieving good neurological outcomes and successful resuscitation are important, so the authors investigated predictors of favorable neurological outcomes rather than survival after ECPR.

The study’s primary endpoint was neurological outcome at hospital discharge, assessed with the Glasgow-Pittsburgh Cerebral Performance Categories (CPC) scale (1 to 5, as shown in Table 1). CPC 1 and 2 were classified as good neurological outcomes. CPC 3, 4, and 5 were considered poor neurological outcomes.

Of 115 patients, 68 (59%) had good neurological outcomes but 47 (41%) did not (Figure 2). Therapeutic hypothermia was performed in 10 patients (5%). Mean duration of ECMO support was 47.5 (range 18.5–101) hours. Total length of stay in intensive care unit (ICU) was 11 (range 7–22.5) days and 24 patients died from brain death.

Univariate analysis showed no differences between the good and poor neurological outcome groups for age, comorbidities, bystander CPR, therapeutic hypothermia, total bilirubin, creatinine, 24-hour lactic acid clearance, ROSC before ECMO, or ROSC time (Table 2).

Multivariate analysis revealed neurological outcomes were affected by hemoglobin level, serum lactic acid before ECMO insertion, and interval from cardiac arrest to ECMO (Figure 3). However, age, gender, cardiac arrest out of the hospital, hemoglobin level after ECMO, acute coronary syndrome, initial shockable rhythm, and CPR duration were not independent predictors of neurological outcomes (Table 3).

An algorithm for preoperative cardiac risk assessment

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One discussion last week involved cardiac arrest in the setting of hernia repair. The reference below was highlighted in the chief resident’s presentation.

Reference: Rafiq A, Skylar E, Bella JN. Cardiac evaluation and monitoring of patients undergoing noncardiac surgery. Health Services Insight. 2017 Feb 20; 9: 1178632916686074. doi: 10.1177/1178632916686074.

Summary: Cardiovascular complications in the perioperative period are one of the most common events leading to increased morbidity and mortality. Although such events are very small in number, they are associated with a high mortality rate making it essential for physicians to understand the importance of perioperative cardiovascular risk assessment and evaluation. Its involves a detailed process of history taking, patient’s medical profile, medications being used, functional status of the patient, and knowledge about the surgical procedure and its inherent risks.

That being said, this review by Rafiq et al (2017) aims to provide a concise but comprehensive analysis on all such aspects of perioperative cardiovascular risk assessment for noncardiac surgeries and provide a basic methodology toward such assessment and decision making.

The ideal approach toward perioperative cardiac risk assessment requires a multidisciplinary team or a dedicated perioperative team of physicians. This leads expert physicians in this field to be involved in patient care with improved communications among primary physicians, anesthesiologist, surgeons, the patient, family members of the patient, cardiologist, and all other ancillary departments of health care involved.

Figure 1: Algorithm for perioperative cardiac risk assessment prior to noncardiac surgery (p.2)

algorithm cardiac

The authors state that it is important to stress the fact that a majority of these recommendations are based, to a large extent, on observational studies and clinical experience. There are only few RCTs that address this matter. It is prudent that more randomized trials are needed to improve on current recommendations, hence leading to further improvement in patient care and management in the perioperative period.

Helicobacter pylori infection: patient management

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One discussion this week involved the management of patients with helicobacter pylori infection.

Reference: DynaMed Plus [Internet]. Ipswich (MA): EBSCO Information Services. 1995 – . Record No. T114484, Helicobacter pylori infection; [updated 2018 Dec 04, cited 2019 Apr 05]. Emory login required. [NOTE: direct link is not functional. Go to DynaMed Plus main page and search “helicobacter pylori infection” to access full content.]

Summary: Management overview (DynaMed Plus, 2018)

  • offer treatment to all patients who test positive for active infection with Helicobacter pylori (ACG Strong recommendation)(1); the clinical efficacy of H. pylori eradication varies among associated conditions
    • peptic ulcer disease
      • in patients with H. pylori-positive duodenal ulcers, H. pylori eradication therapy (alone or in addition to ulcer-healing drugs) may increase ulcer healing, and eradication therapy alone may reduce ulcer recurrence (level 3 [lacking direct] evidence)
      • in patients with H. pylori-positive gastric ulcers, addition of H. pylori eradication therapy to ulcer-healing drugs may not improve ulcer healing but H. pylori eradication therapy alone may reduce ulcer recurrence (level 3 [lacking direct] evidence)
      • peptic ulcer bleeding
        • H. pylori eradication therapy appears more effective than short-term antisecretory therapy or long-term ranitidine in preventing recurrent peptic ulcer bleeding in patients not taking nonsteroidal anti-inflammatory drugs (NSAIDs) (level 2 [mid-level] evidence)
        • H. pylori eradication therapy appears less effective than daily proton pump inhibitor (PPI) for preventing recurrent peptic ulcer bleeding in patients who continue long-term NSAIDs (level 2 [mid-level] evidence)
    • precancerous gastric lesions – H. pylori eradication may reduce progression of lesions (level 3 [lacking direct] evidence)
    • iron deficiency anemia – eradicating H. pylori may improve response to oral iron therapy
    • nonulcer dyspepsia – H. pylori eradication improves but does not eliminate symptoms (level 1 [likely reliable] evidence)
    • chronic gastritis – H. pylori eradication may decrease histologic evidence of gastritis in multiple clinical settings (level 3 [lacking direct] evidence), but may not be associated with improved symptoms in children (level 2 [mid-level] evidence)
    • long-term PPI use – H. pylori eradication reduces healthcare use and may reduce dyspepsia symptoms but not reflux symptoms (level 1 [likely reliable] evidence)
    • long-term NSAID use – H. pylori eradication prevents ulcers and ulcer complications in patients starting NSAIDs (level 1 [likely reliable] evidence) but may be less effective than long-term PPI use (level 2 [mid-level] evidence)
    • immune thrombocytopenia – H. pylori eradication improves platelet count (level 2 [mid-level] evidence)
    • gastroesophageal reflux disease (GERD) – H. pylori eradication does not clearly cause, improve, or worsen GERD symptoms (level 2 [mid-level] evidence)
    • asymptomatic patients – H. pylori eradication may prevent future dyspepsia (level 2 [mid-level] evidence), but low overall risk (< 15%) may not warrant such therapy
  • when choosing therapy, consider all of following(1)
    • patient’s history of penicillin allergy, and history of macrolide exposure
    • patient’s ability to adhere to a multidrug regimen with potential adverse effects
    • sensitivity of regional H. pylori strain to the combination of antibiotics administered (H. pylori clarithromycin resistance is > 15% in many areas of North America); see Antimicrobial resistance considerations in Recommendations section for details

Additional Reading: Chey WD, et al. ACG Clinical Guideline: Treatment of Helicobactor pylori infection. American Journal of Gastroenterology. 2017 Feb;112(2):212-239. doi: 10.1038/ajg.2016.563.

Management of elective surgery for diverticulitis

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One discussion this week was on the management of elective surgery for acute diverticulitis.

Reference: Wieghard N, Geltzeiler CB, Tsikitis VB. Trends in the surgical management of diverticulitis. Annals of Gastroenterology. 2015 Jan-Mar;28(1):25-30.

Summary: Wieghard et al (2015) state that sigmoid diverticulitis is an increasingly common Western disease associated with a high morbidity and cost of treatment. Improvement in the understanding of the disease process, along with advances in the diagnosis and medical management has led to recent changes in treatment recommendations. The natural history of diverticulitis is more benign than previously thought and despite current recommendations of more restrictive indications for surgery, practice trends indicate an increase in elective operations for the treatment of diverticulitis. Due to diversity in disease presentation, in many cases, optimal surgical treatment of acute diverticulitis remains unclear with regard to patient selection, timing, and technical approach in both elective and urgent settings.

The table below (Wieghard et al, 2015, p.28) provides direct comparison between ASCRS and ACPGBI recommendations for surgical treatment:

diverticulitis 1

diverticulitis 2

Additional Reading: Xai J, Paul Olson TJ, Rosen SA. Robotic-assisted surgery for complicated and uncomplicated diverticulitis: a single-surgeon case series. Journal of Robotic Surgery. 2019 Jan 23. doi: 10.1007/s11701-018-00914-x. [Epub ahead of print]

Hyperkalemia: a review of outcomes

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One discussion this week included serum potassium levels in the setting of chronic kidney disease (CKD).

Reference: Montford JR, Linas S. How dangerous is hyperkalemia? Journal of the American Society of Nephrology. 2017 Nov; 28(11):3155-3165. doi: 10.1681/ASN.2016121344

Summary: A recent review article by Montford and Linas (2017) summarizes the clinical data linking hyperkalemia with poor outcomes and discusses how the efficacy of certain treatments might depend on the clinical presentation. Below are some points from the section on CKD.

One of the first studies to demonstrate an independent association of hyperkalemia and risk of subsequent death involved a large retrospective study of Japanese patients with advanced CKD presenting for dialysis initiation. An initial serum potassium level >5.5 meq/L at dialysis vintage was the strongest single independent predictor of mortality after an average of 15 years of follow-up. In patients on hemodialysis, potassium levels >5.6 and >5.7 meq/L have been associated with higher mortality. This is also reflected in patients on peritoneal dialysis, with one study suggesting hyperkalemia >5.5 meq/L is associated with a heightened risk of death. Potassium increases during longer intradialytic intervals, and many have attempted to link these fluctuations to the higher incidence of sudden cardiac death in patients with ESRD.

A recently published retrospective observational trial of 52,734 patients on a Monday/Wednesday/Friday hemodialysis schedule revealed that serum potassium levels 5.5–6.0 meq/L were associated with higher risk for subsequent hospitalization, emergency department visits, and mortality within 4 days of measurement.

Management of massive and submassive PE

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A discussion this week included the management of massive and submassive pulmonary embolism (PE).

Reference: Aggarwal V, et al. Acute management of pulmonary embolism. American College of Cardiology. 2017 Oct 24.

Summary: The severity of PE is stratified into massive (PE causing hemodynamic compromise), submassive (PE causing right ventricular dysfunction demonstrable by echocardiography, computed tomography or elevated cardiac biomarkers) and non-massive or low-risk (PE without evidence of RV dysfunction or hemodynamic compromise). The International Cooperative Pulmonary Embolism Registry (ICOPER) demonstrated 90-day mortality rates of 58.3% in patients with massive PE versus 15.1% in sub-massive PE.

Anticoagulation 

Anticoagulation therapy is the primary treatment option for most patients with acute PE. The utilization of factor Xa antagonists and direct thrombin inhibitors, collectively termed Novel Oral Anticoagulants (NOACs) are likely to increase as they become incorporated into societal guidelines as first line therapy.

Inferior vena cava filters

The role of inferior vena cava filters (IVCF) in the contemporary management of acute VTE has not been truly defined owing to a paucity of high quality evidence. At present the benefit of IVCF use seems to be in reducing the risk of acute PE in patients who have a clear contraindication to anticoagulation in the form of active bleeding.54,55 In the absence of such a contraindication there appears to be no clear benefit and non-retrieval of IVCF exposes the patient to risk of recurrent VTE, PTS and other mechanical complications such as filter fracture or migration.

Percutaneous Mechanical Thrombectomy (PMT) for Massive and Submassive Acute PE

Several percutaneous approaches have been used alone or in combination in patients with an absolute contraindication to thrombolysis: thrombus fragmentation, aspiration thrombectomy, rheolytic thrombectomy, and suction embolectomy.

Caution must be exercised during the placement of all catheters into the pulmonary arterial circulation. Ensuring proper positioning is vital in order to prevent the risk of catastrophic vessel injury as well as distal embolization of thrombus when using high-pressure injection systems. For this reason, the American College of Cardiology (Aggarwal et al, 2017) advocate the use of available computed tomography to help guide the optimal placement of any drug delivery system. Suction embolectomy devices such as the Greenfield catheter benefit from being large bore catheters capable of achieving thrombus removal without the side effects associated with fragmentation and rheolytic techniques. Despite this, technical difficulties related to catheter size have precluded its widespread adoption.

Ultrasound-Assisted CDT (UA-CDT) for Acute PE

For patients without an absolute contraindication to systemic thrombolysis, UA-CDT can be considered. Low energy ultrasound disaggregates fibrin within acute thrombi, this is exploited by the EKOS device (EkoSonic, Bothell, WA), which combines emission of low energy ultrasound and infusion of a thrombolytic agent via a multi side-hole containing catheter. This strategy has been evaluated in the ULTIMA (Ultrasound-Assisted, Catheter-Directed Thrombolysis for Acute Intermediate-Risk Pulmonary Embolism) trial, which demonstrated superiority to anticoagulation alone in improving hemodynamics without a significant increase in bleeding complications.