Pre-operative

Optic nerve sheath diameter and intracranial pressure

There have been a number of studies on the use of ocular ultrasound measurement of optic nerve sheath diameter to non-invasively diagnose raised intracranial pressure. This meta-analysis shows that while it seems to be reasonable, wide confidence intervals suggest caution in its use. It can be employed as an aid certainly, and to dictate further assessment.

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Pre-operative Oral Care and Cancer Surgery Outcome

Oral hygiene may be linked to aspiration of oro-pharyngeal secretions and this study concludes that preoperative oral care by a dentist significantly reduced postoperative complications in patients who underwent cancer surgery.They found reduced pneumonia and even mortality rates. Limitations of the study include its retrospective nature and analysis of an administrative claims database. It clearly deserves further study.

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Surgeon-Anesthesiology Relationship

Legendary patient safety advocate Jeffrey Cooper provides his observations on the impact of the surgeon-anesthesiology relationship on patient safety.

Anesthesiology : surgeons are ignorant of medical/anesthesia issues, underestimate surgical time and blood loss, fail to consider health conditions and patient desires, fail to inform of the likelihood of surgical success and magnitude of recovery.

Surgeon: anesthesiologists cancel easily, long turnover time, don’t appreciate scheduling, inattentive and poor communication of hemodynamics, just want to finish the day, don’t change anesthesia for surgeons’ needs.

Instead of an adversarial approach, he suggests an advance huddle on the premise that both presume competence, intelligence, knowledge and a patient interest focus on the part of the other. Where there is legitimate disagreement about what option to pursue, the debate would center on what’s right for the patient, not who is right.

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Blood: Choosing Wisely

Some recommendations of relevance to anesthesia and perioperative care on anemia and blood usage:

Delay elective surgery in patients who have correctable anemia

To reduce iatrogenic anemia, don’t order blood tests unless they are clinically indicated.

Don’t transfuse if there is no active bleeding or laboratory evidence of coagulopathy.

To manage surgical bleeding, use early antifibrinolytic drugs like tranexamic acid rather than blood transfusion if possible.

In nonemergent settings, avoid transfusion when other interventions are available. Discuss alternative strategies during the informed consent process.

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Anti-platelet Agents and Non-cardiac Surgery

In the past it was conventional to continue aspirin and withhold other antiplatelet agents like Plavix before surgery. However recent studies do not tend to show any particular benefit. One study showed increased bleeding without benefit but this new Cochrane review shows neither harm nor benefit in terms of bleeding, ischemic events or mortality.

Clearly a more nuanced approach may be needed for those with coronary stents or where neuraxial anesthesia is being considered ( blog link )

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Cardiac Risk Prediction

A retrospective observational study compared well established cardiac risk prediction models: (i)the Revised Cardiac Risk Index, (ii)American College of Surgeons National Surgical Quality Improvement Program Surgical Risk Calculator, and (iii)the Myocardial Infarction or Cardiac Arrest calculator.

While agreement was better between the latter two (ACS NSQIP and MICA), there was 30% discordance between assigning high or low risk compared to the RCRI.

The NSQIP certainly seems more modern and comprehensive than the RCRI but the divergence in risk assessment certainly needs to be borne in mind.

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Pre-operative Opiod Use and Characteristics

23% of this group reported pre-operative opioid use. “Age, tobacco use, illicit drug use, higher pain severity, depression, higher Fibromyalgia Survey scores, lower life satisfaction, and more medical comorbidities were independently associated with preoperative opioid use”. Use was highest in those presenting for orthopedic and neurosurgical procedures. This data may be important in pre-operative management, weaning or risk mitigation and peri-operative and post-discharge opioid prescribing.

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SGLT2 Inhibitors and Peri-Op Ketoacidosis

SGLT2 Inhibitors are increasingly promoted for diabetes and this article again highlights the risks of euglycemic ketocacidosis. Fasting, hypovolemia, infection, surgery, bowel preparation, keto diets before bariatric procedures, excessive alcohol are some of the predisposing conditions. Treatment involve some aggressive rehydration and Potassium supplementation with Insulin infusion and sometimes bicarbonate. Prevention may necessitate withholding SGLT2 Inhibitors for up to three days, more than the recommended 24 hours.

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ACEIs, ARBs and Post-Op Renal Injury

ACE Inhibitors and ARBs are commonly held before major non-cardiac surgery. This study showed that such practice did not prevent the development of post-op acute kidney injury. While the other rationale is to hold them to prevent severe or intractable hypotension, this may not be the mechanism causing acute kidney injury.

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