Complications

Preoperative Cardiac Optimization

Another Anaesthesia review discusses the approach to preoperative cardiac risk stratification, hypertension, heart failure, murmurs, beta-blockers and other medication management, and implantable electronic cardiac devices.

Also discussed is the role of preoperative investigation such as EKG, CXR, and Echocardiography, as well as serial monitoring of Troponins and BNP. Some evidence for exercise therapy as a preoperative cardiac prehabilitation is reviewed.

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OR Fires

Another (gated) review seeks to bring attention to the issue of Operating Room fires. It reviews the “fire triangle” of ignition, fuel and oxidizer; the contribution and risks of such factors as electrosurgery, laser, drills, fibreoptic light sources, defibrillators, alcohol skin prep, intestinal gas, drapes and oxygen.

Oxygen is one of the key modifiable factors and advice is to maintain FiO2 below 30%. Over 80% of all OR fires are in surgery on the head, neck and upper chest and a similar percentage under sedation, where local oxygen concentrations can easily increase with nasal cannula flow above (or even less with draping) 4l/min. A lethal combination of oxygen, drapes and alcohol based preps can develop waiting for the cautery to spark a fire, particularly lethal near the patient airway.

Should a fire occur, recommendations are to stop the flow of all airway gases, disconnect the breathing circuit, remove tracheal tubes in airway fires and irrigate with saline, and remove burning materials, extinguish the fire and restore room air breathing.

Fire risk should be included in checklists at briefing and/or timeouts.

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A (free!) guideline is also available from the FDA here

Intrathecal Fentanyl for Cesarean Delivery

This study validates the common use of Fentanyl in spinal anesthesia for Cesarean delivery. It reduces the need for intraoperative supplemental analgesia, reduces nausea and vomiting, with longer time for postoperative first analgesia request, and similar benefits were observed when added to Bupivacaine-Morphine spinals.

There was no difference in conversion to GA, hypotension, the onset of sensory block, or the duration of motor block. The only downside was an increase in pruritus.

The study was a systematic review and meta-analysis.

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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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Residual Neuromuscular Blockade

The incidence of residual neuromuscular blockade after anesthesia is, in short, too high and this retrospective study sought to establish its relationship to hospital costs. While there was not an independent association with hospital cost, there was a greater odds of ICU admission, along with a trend towards increased hospital length of stay.

The findings continue to support rigorous quantitative monitoring of neuromuscular function during anesthesia and adequate reversal to a minimum Train-of-Four of 0.9, and probably more optimally 1.

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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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