Outcomes

Early Postoperative Desaturation and Discharge Outcome

A large retrospective study reviewed oxygen desaturation < 90% in the 10mins after extubation in non-cardiac surgery. It was associated with higher odds of being discharged to a nursing facility, a higher risk of respiratory, renal and cardiovascular complications, as well as increased duration of hospital stay, postoperative intensive care unit admission frequency, and cost. Associated risk factors included high intraoperative FiO2, low FiO2 before extubation, high Neostigmine dose, and higher intraoperative long-acting opioid administration.

The authors note: There was substantial provider variability between anaesthetists in the incidence of postoperative desaturation unexplained by patient‐ and procedure‐related factors. This highlights the difficulty in interpreting retrospective studies, but should at least prompt reflecting on extubation readiness criteria as well as the role of oxygen saturation.

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Sepsis-Associated Acute Kidney Injury

The BMJ provides a comprehensive article on Sepsis-associated acute kidney injury (AKI). It discusses risk factors such as advanced age, chronic kidney disease, cardiovascular disease, diabetes, and liver disease. Review of sepsis definitions and kidney injury scores like RIFLE, AKIN and KDIGO are discussed. Markers beyond creatinine are surveyed, like albuminuria, urine microscopy for casts, NGAL etc.

As well as early detection, early resuscitation is important, with balanced electrolyte solutions rather than 0.9% Saline; controversy exists as to the Surviving Sepsis recommendations of 20mL or more per kg fluid, and the potential negative effects of excess fluid are highlighted.

Vasopressor choices to maintain mean arterial pressure include Norepinephrine and Vasopressin. Dopamine and Phenylephrine have not achieved comparable results or safety. Angiotensin II may have promise in future studies.

Mechanical ventilation, although unavoidable often, may increase AKI risk from multiple mechanisms like changes in intrathoracic pressure, reducing venous return, cardiac output, and renal perfusion, as well as neurohormonal and inflammatory pathways.

Pharmacological treatments for AKI are largely preliminary. Renal Replacememt therapy should not begin too early from recent trials, optimal dose being 20-25mL/kg/hour. Removal of toxins via hemoperfusion has not been proven effective. Nephrotoxic agents should be avoided (NSAIDS, contrast, Hydroxyethyl Starch).

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Preoperative Nutrition Optimization

Anaesthesia continues its preoperative optimization articles.

The frequent occurrence of malnutrition in pre-operative patients results in functional impairment, decreased immune defence, delayed wound healing and organ dysfunction. It increases infectious and non-infectious complications, length of stay, cost, readmission, and mortality. Muscle loss and fatty infiltration occur from disease, stress responses and treatment.

Evidence exists that correcting malnutrition can decrease complications and improve outcome. Assessing malnutrition may involve BMI, weight loss and dietary history and albumin measurement. Tools such as the Duke Peri‐operative Malnutrition Score, and Peri‐Operative Enhancement pathway are discussed. References are also provided to guidelines from the European Society for Clinical Nutrition and Metabolism, American Society of Parenteral Enteral Nutrition, and the American Society for Enhanced Recovery with Peri‐operative Quality Initiative.

Treatment involves protein supplementation and Vitamin D, omega-3 fatty acids, as well as immunonutrition with glutamine, arginine and cysteine. The authors advise a more equal distribution of protein through the day in synergy with exercise.

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WHO Surgical Safety Checklist In Emergency Laparotomy

A global cohort study explored the use and impact of the WHO Surgical Safety Checklist in emergency laparotomy. Once again, the findings were striking in that checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low‐Human Development Index (HDI) countries was half that in high‐HDI countries.

The authors importantly note that the association with lower mortality “is likely to reflect broader health system differences that prioritize safe and effective surgical care, yet the checklist plays an important part”. It focuses a team on better communication, collaboration, empowerment and behavioural changes.

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Multimodal Prehabilitation

There is growing evidence for the use of prehabilitation before major surgery to maximize patients’ nutrition, physical condition and cardiovascular fitness, respiratory status and psychological well-being. This is particularly important in cancer surgery. Patients commonly report reduced functional capacity, pain, fatigue, reduced sleep and appetite long after discharge.

There is a window, albeit narrow, before surgery to implement the supervised exercise and nutritional optimization discussed in this article in Anaesthesia, especially in at risk patients – frail, elderly or cancer patients. Concurrently, optimization of respiratory function, anemia correction, smoking cessation, diabetes and cardiac status should occur.

The logistics and economic ramifications will clearly need to be addressed.

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High Volume Fluid and Pediatric Colectomy Outcome

Restrictive fluid administration has become the standard of care in major abdominal surgery in adults as part of ERAS (enhanced recovery); the RELIEF trial sounded the only caution in terms of renal risk ( link ).

This pediatric paper extends the doctrine in that high volume fluids were associated with increased length of stay, longer time to first meal, and longer need for supplemental oxygen.

The conclusion is that high volume fluid administration during colectomy for pediatric patients is associated with worsened postoperative outcomes suggestive of impaired recovery.

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80% Oxygen during Surgery?

High FiO2 is recommended by the WHO to reduce surgical infections. Concern exists however re the growing evidence of the potential harms and adverse or worse outcomes from too much oxygen in many settings like MI, stroke, lung injury, brain injury and ACLS leading to important recommendations to limit oxygen based on adequate SpO2 values. ( blog link ) This current paper fails to find harm from high FiO2 in terms of atelectasis, cardiovascular events, ICU admission or death.

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Numerous critiques of the WHO recommendation exist eg.

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Pre‐operative respiratory optimization

An expert review of respiratory optimization from Anaesthesia.

It discusses the evidence for approaching conditions such as COPD, Asthma, Obstructive Sleep Apnea and Smoking. A review of the evidence is provided on smoking cessation, exercise testing, exercise training, respiratory muscle training, and how they may impact improved respiratory outcomes post-operatively.

Acute respiratory infections, low Oxygen Saturation or uncontrolled symptoms or signs may be the most clear cut reasons for delaying elective surgery.

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Preoperative Anemia

An Anaesthesia review surveys optimizing preoperative anemia.

Anemia in surgical patients is linked to increased morbidity, kidney failure, infection and mortality. Blood transfusion is also linked to worse outcomes and therefore strategies to optimize anemia preoperatively are important, although the evidence that this will improve outcome is limited but ongoing. 130g/dL is the proposed trigger in both sexes, as the WHO figure of 120g/dL in women would disadvantage them.

Targets for anemia correction include cardiac, obstetric, orthopedic and oncological patients.

Screening is advised at least 30 days before surgery, and at the latest 14 days preoperatively. This may involve Ferritin, Transferrin, CRP, B12, Folate and Crestinine measurement. Logistics and team liaison including primary care is needed.

Oral iron is appropriate if 6 weeks before surgery; intravenous iron is recommended if within 4 weeks of surgery. Erythropoietin is not routinely advised because of the potential for increased thrombotic events and mortality, but may be considered where blood is refused or difficult to obtain.

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Sugammadex and Readmission

A retrospective, observational study (with its inherent limitations) studied Sugammadex compared to Neostigmine for reversal of Rocuronium. The endpoints here were further out and reflected on potential improvements in outcome. “Compared with neostigmine, reversal of rocuronium with sugammadex after major abdominal surgery was associated with a lower incidence of 30-day unplanned readmission, a shorter hospital stay, and lower related hospital charges”.

These striking findings need replication in more controlled and randomized trials.

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