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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EMLA and Infants

While we strive to safely minimize pediatric pain, this meta-analysis found that the use of EMLA cream on the skin for venipuncture in infants less than 3 months did not seem to provide much benefit. EMLA had minimal benefits compared to placebo and no benefit compared to sucrose and/or breastfeeding. Rather it only increased methemoglobin levels and skin blanching. The authors caution it may not be applicable to older infants.

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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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Labor Neuraxial Analgesia Variation

Labor epidurals should be available for all births on maternal request unless contraindicated. This US study found quite a variation between states in neuraxial labor analgesia – from 37 – 80%.

Higher rates were associated with no prior birth, previous Cesarean, labor augmentation or induction. Factors inversely associated with neuraxial analgesia were older maternal age, nonwhite race and Hispanic ethnicity, no private insurance or no insurance, twelfth grade or less as the highest level of education, and late or no prenatal care, and the odds reduced with non-physician birth attendants and midwives.

Efforts should be made to decipher the meaning of these variations in terms of sociodemographic and economic influences, disparity, vulnerable groups and access to quality obstetric anesthesia care.

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Anesthesia Induction and Hypoxia

A prospective trial sought to determine the risk factors for hypoxia after pre-oxygenation during anesthesia induction. Hypoxia was observed in 6.6%. Risk factors were: chronic obstructive pulmonary disease, hypertension, anticipated difficult mask ventilation and difficult tracheal intubation, and emergency surgery.

Difficult pre-oxygenation was observed in 30%. Male sex, chronic obstructive pulmonary disease, hypertension, emergency surgery, and predictable difficult mask ventilation were independent patient risk factors for difficult preoxygenation.

This suggests targeting better pre-oxygenation strategies as an important measure to prevent hypoxia. Such measures have included CPAP and BIPAP but an increasingly popular measure is high flow nasal oxygen, or THRIVE (trans-nasal humidified rapid insufflation ventilators exchange). At its simplest, pre-oxygenation by cranking conventional nasal prongs to 15+ l/min may buy time in addition to a face-mask.

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Health related quality of life after ICU

Much has been reported on neuropsychiatric and cognitive sequelae of critical illness. This systematic review found that health-related quality of life was worse for ICU survivors compared to population norms. Pre-existing quality of life was poorer also. The improvement that did occur was in the first year, in the domains of physical function, physical role, vitality and social function. The ICU pathologies were heterogeneous, including sepsis and ventilated patients.

The study confirms current views that cure does not occur at ICU, or even hospital discharge and follow-up and interventions should occur in the first year to maximize better health-related quality of life.

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Anesthesiologist Specialization and Use of General Anesthesia for Cesarean Delivery

A single institution study using data extracted from electronic medical records compares generalist vs. specialized anesthesiologists with regard to general anesthesia for Cesarean delivery.

Specialized providers had a 29% less use of general anesthesia (7.3% vs. 12.1%, 4,052 cases reviewed). However weekend or evening on-call deliveries showed no difference. Emergency Cesarean had a 7-fold higher risk of general anesthesia.

The evidence supports the use of training and staffing models for specialized obstetric anesthesiologists, as neuraxial anesthesia is in general the recommended choice. The authors discuss various possible confounding variables like provider or patient factors, institutional and team dynamics, although they attempted to adjust for some. Also there is no maternal or neonatal outcome data.

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ICDs and Electromagnetic Interference

Bipolar cautery is ideal to minimize electromagnetic interference with Implantable Cardioverter Defibrillators (ICDs).

Where monopolar is used, this study employed protocolized placement of electrosurgery dispersive electrode positioning to divert return current away from the ICD. They found no interference from below-umbilicus procedures but 7% in above-umbilicus procedures and as high as 29% in cardiac surgery (using underbody Megadyne, described as alarmingly high!).

The findings support recommendations that reprogramming and suspending anti-tachycardia functions may be unnecessary in below-umbilicus procedures. However higher risk exists in above-umbilicus procedures and especially in cardiac surgery and underbody dispersive electrodes.

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Nitrous Oxide and Intra-ocular Gas

Intra-ocular air or various gases are used during vitrectomy, commonly after retinal detachment or macular hole surgery, and also with corneal grafts.

The Royal College of Ophthalmologists has issued a warning about these gases, some of which can persist for 8 weeks (1 week or so for air). The diffusibility of Nitrous Oxide may critically increase intra-ocular pressure if used for analgesia or anesthesia at these times. Patients should also carry warning information after the use of such gas/air.

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Cognitive Effects of Perioperative Pregabalin

Gabapentinoids have been shown in many studies to reduce postoperative pain but side effects such as somnolence, dizziness and even respiratory depression have been also reported (not to mention Gabapentinoid misuse and dependence in longer term use). This secondary analysis adds a further caveat in that Pregabalin may increase the risk of developing impaired postoperative cognitive performance, and this may be more important in older or frail patients.

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