This Month in: Anesthesiology

Analysis of nearly 57 million delivery admissions recorded in the Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project between 1998 and 2011 identified an increase in the prevalence of opioid abuse or dependence during pregnancy from 0.17% in 1998 to 0.39% in 2011. Analysis of the most contemporary data set available that preserved the power to explore relatively rare endpoints, deliveries between 2007 and 2011, found opioid abuse or dependence during pregnancy markedly increased the odds of major obstetrical morbidity and mortality after adjusting for age group, race, primary payer, previous cesarean section, multiple gestation, and preexisting maternal conditions.

Impaired coordination between breathing and swallowing is associated with an increased risk of aspiration. The effects of propofol and sevoflurane anesthesia and of hypercapnia on the coordination of breathing and swallowing were studied in 11 healthy volunteers in a randomized controlled trial. Propofol and sevoflurane anesthesia increased the proportion of pathological swallows (i.e., swallows during inspiration or followed by inspiration), and decreased the frequency of swallowing. In addition, carbon dioxide–induced increases in minute ventilation and augmentation of the negative pharyngeal pressure generated during inspiration increased both the frequencies of swallowing and the proportions of pathological swallows during propofol and sevoflurane anesthesia.

When patients present for an anesthetic, the anesthesia team cannot benefit from knowledge of previously successful airway management techniques if they have not been documented in detail. Using a consensus-driven process, local criteria were established for complete airway management documentation. A retrospective review of baseline airway documentation found that only 13.2% of 23,011 general anesthetic records met all of the criteria for the new definition of complete airway management documentation. A combination of process improvement methodologies, including iterative improvements through Plan-Do-Study-Act cycles, increased the rate of complete documentation to a sustained rate of more than 90%.

Fifty-three patients undergoing total knee arthroplasty were randomly assigned to receive single-shot sciatic nerve block (SNB) using either the infragluteal (proximal) or popliteal (distal) technique, or no SNB (placebo). All patients received spinal anesthesia and postoperative continuous-femoral nerve block and multimodal analgesia. Proximal and distal SNB reduced the proportion of patients experiencing moderate-to-severe posterior and anterior knee pain up to 6 h postoperatively, decreased posterior knee pain and anterior knee pain, reduced opioid consumption, and prolonged the time to first analgesic request. The distal approach to SNB was performed more quickly, required fewer needle passes, and produced less patient discomfort.

Toll-like receptors (TLRs) are important elements of the innate immune system that recognize microbes and activate host response to them. While the innate immune response eradicates invading pathogens, excessive inflammatory responses during sepsis may lead to tissue injury, resulting in part from damaged mitochondrial structure and function. Studies in wild type and TLR2-deficient mice subjected to cecum ligation and puncture or a sham procedure found TLR2 signaling contributed to increased intracellular and mitochondrial reactive oxygen species production and mitochondrial dysfunction, including decreased adenosine triphosphate production and decreased mitochondrial membrane potential, in peritoneal leukocytes. However, polymicrobial sepsis produced additional mitochondrial dysfunction that may be TLR2 independent. See the accompanying Editorial View on page 1147.

The elderly patient with a hip fracture can be a medical challenge for the anesthesiologist because such a patient frequently has numerous comorbidities. The conditions that can weaken the elderly patient with a hip fracture are discussed as is the need to balance the potential benefit of any medical intervention that may delay surgery against the fact that delayed surgery is associated with a poorer outcome. Intraoperative management considerations and the benefits of integrated orthopedic and geriatric care to prevent postoperative morbidity and mortality and to promote rehabilitation, the orthogeriatric concept, are presented. See the accompanying Editorial View on page 1144.

Spontaneous intracranial hypotension can occur when cerebral spinal fluid loss due to a dural tear exceeds the ability of the choroid plexus to replace it. The challenge of diagnosing spontaneous intracranial hypotension, the role of imaging studies in making the diagnosis, and the value of an empiric epidural blood patch in treating it are illustrated by a case in which intracranial hypotension occurred due to dural puncture by a vertebral osteophytic spur after a minor fall. An algorithm for managing symptoms of spontaneous intracranial hypotension after failure of conservative measures is provided.

Treatment of hypoxemia in mechanically ventilated patients depends on titration of fraction of inspired oxygen and positive end-expiratory pressure (PEEP) to optimize partial pressure of oxygen in arterial blood. Esophageal balloon manometry enables estimation of pleural pressure and calculation of transalveolar pressure, providing guidance by which PEEP can be increased to minimize both atelectrauma and volutrauma. The case of an obese patient who had suffered an intracerebral hemorrhage and experienced persistent hypoxemia, which was improved by titration of PEEP using esophageal manometry, is presented. The rationale and process for titration of PEEP in mechanically ventilated patients using esophageal manometry is discussed.