Risk of cardiac events after elective versus urgent or emergent noncardiac surgery: Implications for quality measurement and improvement.

INTRODUCTION: Patient populations differ for elective vs urgent and emergent surgery. The effect of this difference on surgical outcome is not well understood and may be important for improving surgical safety. Our primary hypothesis was that there is an association of surgical acuity with risk of postoperative cardiac events. Secondarily, we examined elective vs urgent and emergent patients separately to understand patient characteristics that are associated with postoperative cardiac events. METHODS: We performed a retrospective cohort study of patients ≥65 years undergoing noncardiac elective or urgent/emergent surgery. Logistic regression estimated the association of surgical acuity with a postoperative cardiac event, which was defined as myocardial infarction or cardiac arrest within 30 days of surgery. For the secondary analysis, we modeled the outcome after stratifying by acuity. RESULTS: The study included 161,177 patients with 1014 cardiac events. The unadjusted risk of a postoperative cardiac event was 3.2 per 1000 among elective patients and 28.7 per 1000 among urgent and emergent patients (adjusted odds ratio 4.10, 95% confidence interval 3.56-4.72). After adjustment, increased age, higher baseline cardiac risk, peripheral vascular disease, hypertension, worse American Society of Anesthesiologist (ASA) physical classification, and longer operative time were associated with a postoperative cardiac event. Higher baseline cardiac risk was more strongly associated with postoperative cardiac events in elective patients. In contrast, worse ASA physical classification was more strongly associated with postoperative cardiac events in urgent and emergent patients. Black patients had higher odds of a postoperative cardiac event only in urgent and emergent patients compared to White patients. CONCLUSIONS: Quality measurement and improvement to address postoperative cardiac risk should consider patients based on surgical acuity.

Case Report of Serratus Plane Catheter for Pain Management in a Patient With Multiple Rib Fractures and an Inferior Scapular Fracture.

We placed a superficial serratus anterior plane catheter in an elderly woman with dementia and elevated clotting times who presented with multiple rib fractures after a mechanical fall. She was not a surgical candidate, and treatment consisted of conservative management with physical therapy and pain control. She was not a candidate for a patient-controlled analgesia regimen because of her dementia. Given her elevated international normalized ratio, thoracic epidural and paravertebral analgesia was also contraindicated. We placed an ultrasound-guided serratus anterior plane catheter, allowing titratable continuous infusion in a trauma patient, resulting in excellent analgesia without adverse effects.

Ultrasound-Guided Genicular Nerve Thermal Radiofrequency Ablation for Chronic Knee Pain.

Osteoarthritis (OA) of the knee is one of the most common joint diseases affecting adults in the United States. For elderly patients with multiple medical comorbidities who do not wish to undergo total knee arthroplasty (TKA), lifestyle modification, pharmacologic management, and injections are the mainstay of therapy. Previously, pain management interventions were limited to intra-articular joint injections and viscosupplementation with hyaluronic acid. Fluoroscopic-guided techniques for radiofrequency ablation (RFA) of the genicular nerves have been previously described and a recent cadaveric study suggests that ultrasound-guided genicular nerve blocks can be performed accurately. We performed an ultrasound-guided radiofrequency ablation of the genicular nerves in 88-year-old woman who had deferred surgical management given her age. Following successful ultrasound guided diagnostic genicular nerve blocks, she proceeded to RFA using the same ultrasound guided technique. The procedure resulted in significant pain relief and improvement in overall function for greater than 6 months. The use of ultrasound provides a relatively rapid and noninvasive method to directly visualize genicular nerves and surrounding vasculature. Our case suggests that, for genicular nerve blockade and RFA, ultrasound may be a useful alternative to fluoroscopy. Not only did the procedure result in significant pain relief that has persisted for greater than 6 months but also more importantly her function status and quality of life were improved.

Pain management in critically ill patients: a review of multimodal treatment options.

Pain management for critically ill patients provides physicians with the challenge of maximizing patient comfort while avoiding the risks that arise with oversedation. Preventing oversedation has become increasingly important as we better understand the negative impact it has on patients' experiences and outcomes. Current research suggests that oversedation can result in complications such as thromboembolism, pulmonary compromise, immunosuppression and delirium. Fortunately, the analgesic options available for physicians to limit these complications are growing as more treatment modalities are being researched and implemented in the intensive care unit. Our goal is to outline some of the effective and widely utilized tools available to physicians to appropriately and safely manage pain while avoiding oversedation in the critically ill population.

Truncal blocks for perioperative pain management: a review of the literature and evolving techniques.

As the American healthcare system continues to evolve and reimbursement becomes tied to value-based incentive programs, perioperative pain management will become increasingly important. Regional anesthetic techniques are only one component of a successful multimodal pain regimen. In recent years, the use of peripheral and paraneuraxial blocks to provide chest wall and abdominal analgesia has gained popularity. When used within a multimodal regimen, truncal blocks may provide similar analgesia when compared with other regional anesthetic techniques. While there are other reviews that cover this topic, our review will also highlight the emerging role for serratus plane blocks, pectoral nerve blocks and quadratus lumborum blocks in providing thoracic and abdominal analgesia.

Management of Acute Kidney Injury and Acid-Base Balance in the Septic Patient.

Acute kidney injury (AKI) is an abrupt decrease in kidney function that takes place over hours to days. Sepsis is the leading cause of AKI and portends a particularly high morbidity and mortality, although the severity may vary from a transient rise in serum creatinine to end-stage renal disease. With regard to acid-base management in septic AKI, caution should be used with hyperchloremic crystalloid solutions, and dialysis is often used in the setting of severe acidosis. In the future, biomarkers may help clinicians identify AKI earlier and allow for potential interventions before the development of severe AKI.

Management of intra-aortic balloon pumps.

Intra-aortic balloon pumps (IABPs) continue to be the most widely used cardiac support devices with an annual estimate of 200 000 IABPs placed worldwide. IABPs enhance myocardial function by maximizing oxygen supply and minimizing oxygen demand. The use of IABPs is not without risk, with major vascular injury, ischemia, and infection being the most common complications, especially in high-risk patients. While recent studies have questioned the use of IABPs in patients with cardiogenic shock secondary to myocardial infarction, these studies have limitations making it difficult to formulate definitive conclusions. This review will focus on the mechanisms of counterpulsation, the management of IABPs and the evidence supporting this ventricular support therapy.

Lung ischemia reperfusion injury: a bench-to-bedside review.

Lung ischemia reperfusion injury (LIRI) is a pathologic process occurring when oxygen supply to the lung has been compromised followed by a period of reperfusion. The disruption of oxygen supply can occur either via limited blood flow or decreased ventilation termed anoxic ischemia and ventilated ischemia, respectively. When reperfusion occurs, blood flow and oxygen are reintroduced to the ischemic lung parenchyma, facilitating a toxic environment through the creation of reactive oxygen species, activation of the immune and coagulation systems, endothelial dysfunction, and apoptotic cell death. This review will focus on the mechanisms of LIRI, the current supportive treatments used, and the many therapies currently under research for prevention and treatment of LIRI.

Depletion of calcium stores in injured sensory neurons: anatomic and functional correlates.

BACKGROUND: Painful nerve injury leads to disrupted Ca signaling in primary sensory neurons, including decreased endoplasmic reticulum (ER) Ca storage. This study examines potential causes and functional consequences of Ca store limitation after injury. METHODS: Neurons were dissociated from axotomized fifth lumbar (L5) and the adjacent L4 dorsal root ganglia after L5 spinal nerve ligation that produced hyperalgesia, and they were compared to neurons from control animals. Intracellular Ca levels were measured with Fura-2 microfluorometry, and ER was labeled with probes or antibodies. Ultrastructural morphology was analyzed by electron microscopy of nondissociated dorsal root ganglia, and intracellular electrophysiological recordings were obtained from intact ganglia. RESULTS: Live neuron staining with BODIPY FL-X thapsigargin (Invitrogen, Carlsbad, CA) revealed a 40% decrease in sarco-endoplasmic reticulum Ca-ATPase binding in axotomized L5 neurons and a 34% decrease in L4 neurons. Immunocytochemical labeling for the ER Ca-binding protein calreticulin was unaffected by injury. Total length of ER profiles in electron micrographs was reduced by 53% in small axotomized L5 neurons, but it was increased in L4 neurons. Cisternal stacks of ER and aggregation of ribosomes occurred less frequently in axotomized neurons. Ca-induced Ca release, examined by microfluorometry with dantrolene, was eliminated in axotomized neurons. Pharmacologic blockade of Ca-induced Ca release with dantrolene produced hyperexcitability in control neurons, confirming its functional importance. CONCLUSIONS: After axotomy, ER Ca stores are reduced by anatomic loss and possibly diminished sarco-endoplasmic reticulum Ca-ATPase. The resulting disruption of Ca-induced Ca release and protein synthesis may contribute to the generation of neuropathic pain.

Axotomy depletes intracellular calcium stores in primary sensory neurons.

BACKGROUND: The cellular mechanisms of neuropathic pain are inadequately understood. Previous investigations have revealed disrupted Ca signaling in primary sensory neurons after injury. The authors examined the effect of injury on intracellular Ca stores of the endoplasmic reticulum, which critically regulate the Ca signal and neuronal function. METHODS: Intracellular Ca levels were measured with Fura-2 or mag-Fura-2 microfluorometry in axotomized fifth lumbar (L5) dorsal root ganglion neurons and adjacent L4 neurons isolated from hyperalgesic rats after L5 spinal nerve ligation, compared to neurons from control animals. RESULTS: Endoplasmic reticulum Ca stores released by the ryanodine-receptor agonist caffeine decreased by 46% in axotomized small neurons. This effect persisted in Ca-free bath solution, which removes the contribution of store-operated membrane Ca channels, and after blockade of the mitochondrial, sarco-endoplasmic Ca-ATPase and the plasma membrane Ca ATPase pathways. Ca released by the sarco-endoplasmic Ca-ATPase blocker thapsigargin and by the Ca-ionophore ionomycin was also diminished by 25% and 41%, respectively. In contrast to control neurons, Ca stores in axotomized neurons were not expanded by neuronal activation by K depolarization, and the proportionate rate of refilling by sarco-endoplasmic Ca-ATPase was normal. Luminal Ca concentration was also reduced by 38% in axotomized neurons in permeabilized neurons. The adjacent neurons of the L4 dorsal root ganglia showed modest and inconsistent changes after L5 spinal nerve ligation. CONCLUSIONS: Painful nerve injury leads to diminished releasable endoplasmic reticulum Ca stores and a reduced luminal Ca concentration. Depletion of Ca stores may contribute to the pathogenesis of neuropathic pain.