Proteinuria and Postoperative Kidney Injury

While proteinuria is well documented as a medical risk factor for morbidity, this retrospective review of pre-operative proteinuria in surgical patients finds: “Proteinuria was associated with postoperative acute kidney injury and 30-day unplanned readmission independent of preoperative eGFR. Simple urine assessment for proteinuria may identify patients at higher risk of AKI and readmission to guide perioperative management”.



Crystalloids vs. Colloids in Surgical Hypovolemia

Immense concern has existed regarding the evidence that colloids, in particular starches, increase mortality and renal injury, especially in septic shock. A previous study in critical care however found no mortality difference ( link ). The present subgroup analysis was focussed on critically ill surgical hypovolemic shock needing surgery before or within 24 hours of ICU admission. Again, no difference in mortality or renal injury was found.

Nuances like differentiation between synthetic colloids and albumin, and potential benefits of balanced salt solutions were not addressed so once again, the debate will continue. In particular the results should not at this point be extrapolated to the different population of septic shock patients.



Sleep Apnea and Peri-operative Oitcomes

Obstructive Sleep Apnea is a red flag for surgery and anesthesia and ASA guidelines exist to identify and manage it peri-operatively, based on factors such as its severity, type/magnitude of surgery and need for postoperative opioids. The present study, although based on administrative data, is noteworthy as it involved a common ambulatory procedure, shoulder arthroscopy.

There was an increased risk of pulmonary complications, myocardial infarction, and an increased odds of requiring postoperative ventilation, hospital admission, and intensive care unit admission. These are significant for an ambulatory procedure and emphasize the need for caution in this population.


Adverse side effects of dexamethasone in surgical patients

A single dose of Dexamethasone is widely used in anesthesia as an anti-emetic. This Cochrane review sought to assess the effects of a steroid load of dexamethasone on postoperative systemic or wound infection, delayed wound healing, and blood glucose change in adult surgical patients.

They found a single dose of Dexamethasone did not increase infection within 30 days. The data was inconclusive on wound healing, and there was some increase in blood sugar. They caution on extrapolating such data where infection and wound healing may be more likely, such as diabetes or immunodeficiency. Also the surgeries were very heterogeneous, including cardiac, abdominal, neurosurgery, orthopedic etc. and no differentiation is mentioned between elective and emergency surgery. Further studies are awaited.


Prothrombin Complex Concentrates For Vitamin K Antagonist Reversal

The following figures emerge from this Anesthesiology review: Annual rates of major hemorrhagic events ranged from 1.0 to 7.4% in a systematic review of patients with atrial fibrillation receiving vitamin K antagonist therapy, while rates of intracranial hemorrhage in the same population ranged from 0.1 to 2.5%. Major bleeding occurred in 3.3% of warfarin-treated patients undergoing elective surgery, but 21.6% in patients in emergency surgery

Fresh Frozen Plasma brings risks of fluid overload, lung injury, infection and is slow to act and less effective. Vitamin K alone is feasible only when surgery can be delayed 24-48 hours.

Current guidelines recommend prothrombin complex concentrates (PCC), specifically four-factor prothrombin complex concentrates, with concomitant intravenous vitamin K, as the preferred therapy for urgent vitamin K antagonist reversal, which are effective in 30 minutes or so. PCCs reduces bleeding and some studies suggest mortality also. Many studies show them to be more effective than FVIIa. Thromboembolism has not been found to be increased to date.

Whereas specific reversal agents are in use or being introduced for Factor Xa Inhibitors and Direct Thrombin Inhibitors, PCCs may be worth considering for hemorrhage in such patients in the interim although their efficacy is very variable for non-vitamin K antagonist reversal.

The full review surveys all the published studies and also examines evidence in various scenarios such as intracranial hemorrhage, cardiac surgery and trauma.


Laryngeal Tube and Cardiac Arrest Outcome

A strategy of initial laryngeal tube insertion, compared with endotracheal intubation, was associated with greater likelihood of 72-hour survival after out of hospital cardiac arrest.

There were small differences in secondary outcomes like favourable neurological status. Airway success rates were far higher in the laryngeal tube group and this makes it difficult to compare directly as intubation successes were so low here, about 50%, quite concerning

At least once again, supraglottic airways seem appropriate as a choice of initial airway management.



Midazolam and Dexmedetomidine in Cancer

This is a preclinical study whose clinical significance remains to be determined but illustrates the potential wide ranging effects of medications in the cancer patient.

The study in Anesthesiology found “Midazolam possesses antitumorigenic properties partly mediated by the peripheral benzodiazepine receptor, whereas dexmedetomidine promotes cancer cell survival through signaling via the α2-adrenoceptor in lung carcinoma and neuroglioma cells”.