Gaussian Boson Sampling.

Boson sampling has emerged as a tool to explore the advantages of quantum over classical computers as it does not require universal control over the quantum system, which favors current photonic experimental platforms. Here, we introduce Gaussian Boson sampling, a classically hard-to-solve problem that uses squeezed states as a nonclassical resource. We relate the probability to measure specific photon patterns from a general Gaussian state in the Fock basis to a matrix function called the Hafnian, which answers the last remaining question of sampling from Gaussian states. Based on this result, we design Gaussian Boson sampling, a #P hard problem, using squeezed states. This demonstrates that Boson sampling from Gaussian states is possible, with significant advantages in the photon generation probability, compared to existing protocols.

Driven Boson Sampling.

Sampling the distribution of bosons that have undergone a random unitary evolution is strongly believed to be a computationally hard problem. Key to outperforming classical simulations of this task is to increase both the number of input photons and the size of the network. We propose driven boson sampling, in which photons are input within the network itself, as a means to approach this goal. We show that the mean number of photons entering a boson sampling experiment can exceed one photon per input mode, while maintaining the required complexity, potentially leading to less stringent requirements on the input states for such experiments. When using heralded single-photon sources based on parametric down-conversion, this approach offers an ∼e-fold enhancement in the input state generation rate over scattershot boson sampling, reaching the scaling limit for such sources. This approach also offers a dramatic increase in the signal-to-noise ratio with respect to higher-order photon generation from such probabilistic sources, which removes the need for photon number resolution during the heralding process as the size of the system increases.

Driven quantum walks.

We introduce the concept of a driven quantum walk. This work is motivated by recent theoretical and experimental progress that combines quantum walks and parametric down-conversion, leading to fundamentally different phenomena. We compare these striking differences by relating the driven quantum walks to the original quantum walk. Next, we illustrate typical dynamics of such systems and show that these walks can be controlled by various pump configurations and phase matchings. Finally, we end by proposing an application of this process based on a quantum search algorithm that performs faster than a classical search.

Bilateral ultrasound-guided supraclavicular block in a patient with severe electrocution injuries of the upper extremities.

The performance of bilateral supraclavicular brachial plexus nerve blocks is controversial. We present the challenging case of a 29-year-old male who suffered bilateral high-voltage electrocution injuries to the upper extremities, resulting in severe tissue damage, sensory and motor deficits, and wounds in both axillae. This injury necessitated bilateral below-elbow amputations. His postoperative course was complicated by pain refractory to intravenous narcotics. The decision was made to attempt bilateral supraclavicular brachial plexus blocks. Our concerns with this approach included the risks of pneumothorax and respiratory failure due to phrenic nerve block. Initial attempts at brachial plexus blockade using nerve stimulation were unsuccessful; therefore, ultrasound guidance was employed. With vigilant monitoring in an intensive care unit setting, we were able to safely perform bilateral continuous supraclavicular brachial plexus nerve blocks with an excellent analgesic response and no noted complications.

Psychiatric agents and implications for perioperative analgesia.

The use of antidepressants, anxiolytics, mood stabilizers, anticonvulsants, and major tranquilizers introduces neurochemical, behavioral, cognitive, and emotional factors that increase the complexity of medical and surgical tasks. Increasingly, various classes of psychotropic medications are being prescribed in the perioperative setting for their analgesic properties in patients with or without a psychiatric diagnosis. In many cases, the precise mechanisms of action and dose-response relationships by which these agents mediate analgesia are largely unclear. An appreciation of the side effects and adverse-effect profiles of such medications and familiarity with the clinically relevant drug interactions that may occur in the perioperative setting are imperative to ensure the best possible outcome in dealing with patients on these medications. This review focuses on various classes of psychotropic agents, which are addressed individually, with particular focus on their analgesic properties. The latest published research is summarized, deficiencies in our current collective knowledge are discussed, and evidence-based recommendations are made for clinical practice.

Intraoperative and Postoperative Blood Glucose Concentrations in Diabetic Surgical Patients Receiving Lactated Ringer's Versus Normal Saline: A Retrospective Review of Medical Records.

BACKGROUND: Hyperglycemia is associated with poor postoperative outcomes after carotid endarterectomy. This retrospective study examined the effect of lactated Ringer's and normal saline solutions on intraoperative blood glucose control in diabetic patients undergoing carotid endarterectomy. METHODS: The anesthetic and surgical records of type 2 diabetic patients who underwent carotid endarterectomy and received either lactated Ringer's solution or normal saline exclusively during the case were reviewed, and 20 patients were randomly selected from each group for further analysis. The outcome of interest was preoperative to postoperative change in blood glucose. RESULTS: The preoperative to postoperative mean changes in glucose for the normal saline and lactated Ringer's groups were 34.4 ± 70.32 mg/dL and 64.5 ± 61.38 mg/dL, respectively. This slight difference in the mean change in glucose between the 2 groups was not statistically significant (P=0.157). CONCLUSION: Lactated Ringer's solution does not appear to cause a significant change in the mean blood glucose levels in diabetic patients undergoing carotid endarterectomy compared to patients receiving normal saline. Randomized controlled trials are needed to further determine whether lactated Ringer's solution adversely affects glucose control in diabetic surgical patients.