Outcomes

Volatile Anesthetics vs. Total Intravenous Anesthesia for Cardiac Surgery

The ‘cardioprotective’ effects of volatile anesthesia gases have been seen as useful during coronary artery bypass surgery (CABG). This controlled study in elective CABG compared volatile anesthesia with total intravenous anesthesia (TIVA) and found no difference in 30 day or 1 year mortality.

The findings are important as anesthetic gases have been even recommended as useful in American and European guidelines, based on known cellular protective effects and effects on cardiac biomarkers, and suggested by previous observational and meta-analysis studies.

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Transfusion-Associated Circulatory Overload in ICUs

Transfusion-associated circulatory overload is frequent in ICU patients, about 5.5% in this review. It was associated with increased ICU and hospital length of stay.

Risk factors included positive fluid balance, the number and type of products transfused, rate of transfusion, and cardiovascular and renal comorbidities. 

In pediatric ICUs, the authors note “The lack of a pediatric-adjusted definition of transfusion-associated circulatory overload may lead to a risk of underdiagnosis of this condition in PICUs”.

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Cesarean Maternal & Neonatal Mortality in Africa

Maternal mortality after cesarean delivery in Africa is 50 times higher than that of high-income countries and is driven by peripartum haemorrhage and anaesthesia complications. Neonatal mortality is double the global average.

These shocking figures from a prospective observational study across Africa may be due to such factors as poor access to caesarean delivery, peripartum hemorrhage, and provision of anesthesia by non-physicians.

Suggested areas to improve include risk identification (eg, ASA status, risk of bleeding), care bundles and checklists and a higher level of monitoring, use of antifibrinolytic drugs (tranexamic acid), improved access to blood and blood products with long shelf lives, such as freeze-dried plasma and fibrinogen; and novel methods of training of non-physician anaesthetists, including online support and mobile-based applications.

Intraoperative Goal-directed Balanced Crystalloid versus Colloid

Another piece for the perpetual puzzle as to the harms and/or benefits of colloids vs. crystalloids.

The potential serious kidney injury and mortality using Hydroxyethyl Starch reported in critical illness are not always replicated in the intraoperative setting.

In this study in abdominal surgery, the primary outcome was a composite of serious postoperative cardiac, pulmonary, infectious, gastrointestinal, renal, and coagulation complications. Creatinine at 6 months was assessed.

Lactated Ringers or Hydroxyethyl Starch were given in a goal directed manner using esophageal Doppler based on stroke volume and corrected aortic flow time.

“Doppler-guided intraoperative hydroxyethyl starch administration did not reduce composites of serious complications. Nor did hydroxyethyl starch reduce the duration of hospitalization, but there was also no indication of renal or other toxicity”.

No clear reason to use Hydroxyethyl Starch is apparent, in view of the greater cost.

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Acute Pain Trajectories and Remote Pain Resolution

A secondary analysis of the Stanford Accelerated Recovery Trial assessed remote postoperative pain, opioid use, and recovery. The incidence of persistent postsurgical pain ranges from 10% to 50%, and 2% to 10% of patients report severe, chronic pain after surgery.

The study assessed high and low pain clusters in the first 10 days in a mixed surgical cohort. Numerous pain and other scores were administered. The authors identified worst pain over the past 24 hours reported on postoperative day 10 as a significant immediate postoperative predictor of remote pain resolution, opioid cessation, and complete surgical recovery.

The implications are summarized: “Ultimately, early identification of high-risk patients would facilitate personalized care with closer follow-up, earlier referral for specialist care, and extension of multimodal pain regimens”.

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Lidocaine and Neurologic Outcomes after Cardiac Surgery

50% of cardiac surgery patients leave hospital with cognitive dysfunction which tends to improve but may persist at 5 years in some. Based on previous suggestion that Lidocaine may ameliorate such issues due to postulated anti-inflammatory, blood flow, and cerebral metabolism mechanisms, this randomized study failed to find benefit with use of Lidocaine infusion during and for 48 hours after cardiac surgeries.

Conclusion: Intravenous lidocaine administered during and after cardiac surgery did not reduce postoperative cognitive decline at 6 weeks.

The authors note the complex issues involved in cognitive dysfunction that could not be expected to benefit from a single agents – preoperative cognitive impairment, genetic predisposition, cerebral microembolism or hypoperfusion during CPB, inflammatory responses, hemodilution, hyperglycemia, hyperthermia, unmasking of Alzheimer disease, and acceleration of amyloid deposition associated with inhalational anesthetics.

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Perioperative Hypotension and Cardiovascular Events

Another study adds to the now established theme that perioperative hypotension increases cardiovascular events and does so independently of the degree of coronary artery disease.

Hypotension is defined in this study as systolic blood pressure < 90mm Hg for at least 10 mins. Other studies have also used mean arterial pressure < 65.

The nuances show the effects were additive if not multiplicative. There was insufficient evidence that perioperative hypotension may have less deleterious cardiovascular effects in patients with a lesser degree of coronary artery disease compared to greater coronary artery disease.

“These data support efforts for the prevention, monitoring, and treatment of perioperative hypotension regardless of the presence or absence of significant coronary artery disease”.

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Intraoperative Controlled Hypotension and Acute Kidney Injury

This was a retrospective study (immediate caveat!) on total hip arthroplasty under neuraxial anesthesia with intraoperative controlled hypotension (MAP < 60).

Acute kidney injury occurred in 45 (1.85%) of the 2431 patients in this cohort. Longer duration of hypotension was not associated with increased odds of postoperative AKI. Preexisting differences, such as compromised renal function, best predicted increased odds of AKI.

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The authors speculate that inadvertent and controlled hypotension may be different. Hypotension may have surgical benefits but this study should be interpreted with caution in view of the known evidence on the cardiac, renal and mortality associations ( link ).

Methylprednisolone for AKI in Cardiac Surgery

A sub study of a randomized trial finds: “Intraoperative corticosteroid use did not reduce the risk of acute kidney injury in patients with a moderate-to-high risk of perioperative death who had cardiac surgery with cardiopulmonary bypass. Our results do not support the prophylactic use of steroids during cardiopulmonary bypass surgery”.

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A previous review casts doubt on the use of steroids for various purposes in cardiac surgery, finding that they had “an unclear impact on mortality, increased the risk of myocardial injury, and the impact on atrial fibrillation should be viewed with caution given that large trials showed no effect”. link

Delirium in Older Acute Care Surgery

Patients older than 65 years were followed after acute care surgery. Some 23% had delirium from a validated chart review.

Postoperative delirium risk factors included Foley catheter use, intestinal surgery, gallbladder surgery, appendix surgery, intensive care unit admission and mild to moderate frailty. Risk factors for prolonged postoperative delirium (> 48 hours) included Foley catheter use and mild to moderate frailty. Surgical approach (open v. laparoscopic) and overall operative time were not found to be significant.

The seemingly innocuous Foley urinary catheter consistently appears as a delirium risk factor and protocols to ask every day whether it can be removed are appropriate.

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