Overflow waters in the western Irminger Sea modify deep sound speed structure and convergence zone propagation.

Deep sound speed structure in the western Irminger Sea is found to be highly dynamic in comparison to the adiabatic (uniform) sound speed gradient underpinning data assimilation and modeling efforts around the globe. A beamed source parabolic equation model is used to illustrate how the resulting non-uniform sound speed structure at 1 to 1.5 km in depth and sound speed inversion near the seafloor produce observable effects on acoustic signals between a shallow source and shallow vertical line array at convergence zone ranges. Beamforming analysis shows that a uniform sound speed gradient leads to "ideal" interference patterns that do not capture or represent modeled convergence zone properties, such as location, strength, and sharpness. Overall findings suggest that in situ information about sound speed below 1 km is necessary for low frequency, long-range propagation studies, particularly in areas of complex thermohaline circulation.

Comparison of Femoral Nerve Catheter, Adductor Canal Catheter, and Periarticular Liposomal Bupivacaine Infiltration for Postoperative Analgesia After Primary Total Knee Arthroplasty.

BACKGROUND: Peripheral nerve catheters are used to provide analgesia after total knee arthroplasty (TKA) and have been shown to decrease pain and opioid use, to facilitate participation with physical therapy (PT), and to hasten discharge. More recently, pericapsular infiltration using liposomal bupivacaine (LB) has been employed as an alternative analgesic approach. METHODS: This retrospective study compared outcomes for three analgesic approaches: femoral nerve catheter (FNC), adductor canal catheter (ACC), and intraoperative LB infiltration. The primary outcome was numeric rating scale (NRS) pain scores at 24 hours. Secondary outcomes included pain scores at 12, 36, and 48 hours, time-to-first opioid, cumulative opioid use, distance walked, and time-to-discharge. RESULTS: Pain scores at 24 hours were significantly lower in both the ACC and FNC cohorts when compared to the LB cohort (3.1 versus 4.6 [P = .017] and 2.4 versus 4.6 [P < .0001]). The ACC and FNC groups did not differ significantly at that timepoint (P = .27). Similar comparisons were found at 12 and 36 hours, while at 48 hours the FNC group was superior. Time to first opioid and opioid consumption favored the ACC and FNC groups. Walking distance favored the ACC group. Both the ACC and LB groups had a faster time-to-discharge than the FNC group. CONCLUSION: Both ACCs and FNCs provided superior analgesia at 24 hours compared to LB, while being equivalent to each other. Pain scores at 12 hours and 36 hours as well as opioid consumption through 48 hours mirrored this finding. Although various differences were found between groups in terms of time-to-first analgesic, walking distance and time-to-discharge, the ACC approach appeared to optimally balance analgesia, ambulation, and time-to-discharge.

A randomized comparison of loss of resistance versus loss of resistance plus electrical stimulation: effect on success of thoracic epidural placement.

BACKGROUND: Loss of resistance (LOR) for epidural catheter placement has been utilized for almost a century. LOR is a subjective endpoint associated with a high failure rate. Nerve stimulation (NS) has been described as an objective method for confirming placement of an epidural catheter. We hypothesized that the addition of NS to LOR would improve the success of epidural catheter placement. METHODS: One-hundred patients were randomized to thoracic epidural analgesia (TEA) utilizing LOR-alone or loss of resistance plus nerve stimulation (LOR + NS). The primary endpoint was rate of success, defined as loss of sensation following test dose. Secondary endpoints included performance time. An intention-to-treat analysis was planned, but a per-protocol analysis was performed to investigate the success rate when stimulation was achieved. RESULTS: In the intention-to-treat analysis there was no difference in success rates (90% vs 82% [LOR + NS vs LOR-alone]; P = 0.39). The procedural time increased in the LOR + NS group (33.9 ± 12.8 vs 24.0 ± 8.0 min; P < 0.001). The per-protocol analysis found a statistically higher success rate for the LOR + NS group compared to the LOR-alone group (98% vs. 82%; P = 0.017) when only patients in whom stimulation was achieved were included. CONCLUSIONS: Addition of NS technique did not statistically improve the success rate for epidural placement when analyzed in an intention-to-treat format and was associated with a longer procedural time. In a per-protocol analysis a statistically higher success rate for patients in whom stimulation was obtained highlights the potential benefit of adding NS to LOR. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT03087604 on 3/22/2017; Institutional Review Board Wake Forest School of Medicine IRB00039522, Food and Drug Administration Investigational Device Exemption: G160273.

Utility of the Pectoral Nerve Block (PECS II) for Analgesia Following Transaxillary First Rib Section.

BACKGROUND: The transaxillary approach to resection of the first rib is one of several operative techniques for treating thoracic outlet syndrome. Unfortunately, moderate to severe postoperative pain is anticipated for patients undergoing this particular operation. While opioids can be used for analgesia, they have well-described side effects that has led investigators to search for clinically relevant alternative analgesic modalities. We hypothesized that a regional analgesic procedure, commonly called a pectoral nerve (PECS II) block, which anesthetizes the second through sixth intercostal nerves as well as the long thoracic nerve and the medial and lateral pectoral nerves, would improve postoperative analgesia for patients undergoing a transaxillary first rib resection. METHODS: We performed a retrospective study by reviewing the charts of all patients that had undergone a transaxillary first rib resection for thoracic outlet syndrome during the defined study period. Patients that received a PECS II block were compared to those that did not. The primary outcome was a comparison of numeric rating scale pain scores during the first 24 hours following the operation. Secondary outcomes included cumulative opioid consumption during the same time period. RESULTS: Pain scores during the first 24 hours following the operation were not statistically different between groups (Block Group: 3.9 [2.1-5.3] [median (IQR 25-75%)] versus Non-block Group: 3.6 [2.4-4.1]; P = 0.40. In addition, opioid use through the first 24 hours after the operation was not significantly different (43.5 [22.0-81.0] [median morphine equivalents in mg's] versus 42.0 [12.5-75.0]; P = 0.53). CONCLUSIONS: An ultrasound-guided PECS II nerve block did not reduce postoperative pain scores or opioid consumption for patients undergoing a transaxillary first rib resection. However, a prospective, randomized, study with improved power would be beneficial to further explore the potential utility of a PECS II block for patients presenting for this surgical procedure.

Analgesic Benefit of Pectoral Nerve Block II Blockade for Open Subpectoral Biceps Tenodesis: A Randomized, Prospective, Double-Blinded, Controlled Trial.

BACKGROUND: Axillary pain is common after arthroscopic shoulder surgery with an open subpectoral biceps tenodesis. We hypothesized that adding a pectoral nerve block II (Pecs II) to an interscalene block (ISB) would improve postoperative analgesia in this surgical population. METHODS: Forty patients were enrolled in this prospective, randomized, observer and patient-blinded, single-institution trial. All 40 patients received a single-injection ISB with 20 mL of 0.25% bupivacaine with 1:400,000 epinephrine and 1:600,000 clonidine. The intervention arm (ISB + Pecs II) consisted of 20 patients who also received a Pecs II block using 30 mL of 0.25% bupivacaine with 1:400,000 epinephrine and 1:600,000 clonidine. The 20 control group patients (ISB) received a sham Pecs II block. The primary outcome was postoperative pain scores at 6 hours using the numeric rating scale (NRS; range, 0-10) and was analyzed using the Mann-Whitney U test. Secondary outcomes included the presence of axillary pain at 6 hours, the need for postanesthesia care unit (PACU) opioids, PACU length of stay (LOS) (minutes), NRS pain scores at 24 hours, cumulative opioid usage postdischarge through 24 hours, the presence of nausea or vomiting during the first 24 hours, and Pecs II block duration (in hours, based on time to onset of axillary pain). Data were analyzed using a modified intention-to-treat (ITT) methodology. RESULTS: Pain scores (NRS, 0-10) at 6 hours differed significantly between groups: ISB 3.0 (0.25-5.0) (1.7-4.3) versus ISB + Pecs II 0.0 (0-2.0) (0.0-1.1) (median [IQR] [95% CI]); P = .026. Hodges-Lehmann estimator of the difference was 2.0 (95% CI, 0.0-4.0). Fewer patients in the ISB + Pecs II group reported axillary pain at 6 hours and fewer required opioids in the PACU. There were no differences in any of the remaining secondary outcomes. CONCLUSIONS: The addition of a Pecs II block to an ISB for patients undergoing arthroscopic shoulder surgery with an open subpectoral biceps tenodesis significantly improved postoperative analgesia and reduced the need for opioids in the PACU.

Single-Injection Adductor Canal Block With Multiple Adjuvants Provides Equivalent Analgesia When Compared With Continuous Adductor Canal Blockade for Primary Total Knee Arthroplasty: A Double-Blinded, Randomized, Controlled, Equivalency Trial.

BACKGROUND: Peripheral nerve blockade is used to provide analgesia for patients undergoing total knee arthroplasty. This study compared a single-injection adductor canal block (SACB) with adjuvants to continuous adductor canal blockade (CACB). The hypothesis was that the 2 groups would have equivalent analgesia at 30 hours after neural blockade. METHODS: This was a double-blinded, randomized, controlled, equivalency trial. Sixty patients were randomized to either the SACB group (20 mL of 0.25% bupivacaine, 1.67 mcg/mL of clonidine, 2 mg of dexamethasone, 150 mcg of buprenorphine, and 2.5 mcg/mL of epinephrine) or the CACB group (20 mL 0.25% of bupivacaine injection with 2.5 mcg/mL of epinephrine followed by an 8 mL/h infusion of 0.125% bupivacaine continued through postoperative day 2). The primary outcome was movement pain scores at 30 hours using the numeric rating scale (NRS). The secondary outcomes included serial postoperative NRS pain scores (rest and movement every 6 hours), opioid consumption, time to first opioid administration, ability to straight leg raise, patient satisfaction, length of stay, and the incidence of nausea/vomiting. RESULTS: An intention-to-treat analysis included 59 patients. The NRS pain scores with movement were equivalent at 30 hours (SACB 5.5 ± 2.8 vs CACB 5.7 ± 2.9 [mean NRS ± standard deviation]; mean difference 0.2 [-1.5 to 1.0 {90% confidence interval}]). All NRS pain scores were equivalent until 42 hours (rest) and 48 hours (rest and movement) with the CACB group having lower pain scores. Other secondary outcomes were not statistically different. CONCLUSION: An SACB provides equivalent analgesia for up to 36 hours after block placement when compared with a CACB for patients undergoing total knee arthroplasty, though a CACB was favored at 42 hours and beyond.

Evaluation of a wireless, portable, wearable multi-parameter vital signs monitor in hospitalized neurological and neurosurgical patients.

Unrecognized changes in patients' vital signs can result in preventable deaths in hospitalized patients. Few publications or studies instituting routine patient monitoring have described implementation and the setting of alarm parameters for vital signs. We wanted to determine if continuous multi-parameter patient monitoring can be accomplished with an alarm rate that is acceptable to hospital floor nurses and to compare the rate of patient deterioration events to those observed with routine vital sign monitoring. We conducted a prospective, observational, 5-month pilot study in a 26-bed adult, neurological/neurosurgical unit (non-ICU) in an academic medical center. A patient surveillance system employing a wireless body-worn vital signs monitor with automated nursing notification of alarms via smartphones was used to gather data. Data collected included: alarm rates, rapid response team (RRT) calls, intensive care unit (ICU) transfers, and unplanned deaths before and during the pilot study. Average alarm rate for all alarms (SpO2, HR, RR, NIBP) was 2.3 alarms/patient/day. The RRT call rate was significantly reduced (p < 0.05) from 189 to 158 per 1000 discharges. ICU transfers per 1000 discharges were insignificantly reduced from 53 to 40 compared to the previous 5-month period in the same unit. Similar measures of comparison units did not change over the same period. Although unplanned patient deaths in the study unit were also reduced during the intervention period, this was not statistically significant. Continual, multi-parameter vital signs monitoring can be customized to reduce a high alarm rates, and may reduce rapid response team calls.

An Evaluation of Ultrasound-Guided Adductor Canal Blockade for Postoperative Analgesia After Medial Unicondylar Knee Arthroplasty.

BACKGROUND: Unicondylar knee arthroplasty (UKA) is a commonly performed procedure with significant expected postoperative pain. Peripheral nerve blocks are 1 analgesic option, but some approaches may decrease quadriceps motor strength and interfere with early ambulation. In this study, we compared the analgesia provided by an adductor canal block (ACB) and a psoas compartment block (PCB) after UKA. We hypothesized that the ACB would provide equivalent analgesia, defined as a difference of <2 points on the pain scale (0-10 numeric rating scale [NRS]), at rest and with movement 6 hours after block placement. METHODS: One hundred fifty patients undergoing medial UKA were randomly assigned to receive either an ACB or a PCB with 0.25% bupivacaine, 5 µg/mL epinephrine, and 1.67 µg/mL clonidine. All patients received multimodal analgesics, sham blockade at the alternate site, and a posterior capsule injection during surgery. Patients and observers were blinded to treatment groups. The primary end points were NRS pain scores with rest and movement at 6 hours. Secondary end points included quadriceps muscle strength at 6 hours (0-5 [5 being full strength]; Medical Research Council scale) as well as NRS pain scores, opioid consumption, and opioid-related side effects over 24 hours. RESULTS: One hundred forty-seven patients were analyzed. Pain scores were equivalent at 6 hours with rest (ACB 1.0 ± 2 vs PCB 1.1 ± 2.2 [mean NRS ± SD]; 95% confidence interval of mean difference, -0.8 to 0.6; P < 0.0001) and with movement (ACB 1.6 ± 2.6 vs PCB 1.5 ± 2.8; 95% confidence interval of mean difference, -0.8 to 0.9; P < 0.0001). In addition, pain scores at rest and with movement at 12, 18, and 24 hours were equivalent. Quadriceps motor strength was significantly increased in the ACB group (Medical Research Council scale score, 4.0 ± 1.1 vs 2.5 ± 1.3 [mean ± SD]; P < 0.0001). No significant differences were found between groups for time to first analgesic or for cumulative opioid consumption at 6, 12, 18, or 24 hours. Other than an increase in the incidence of pruritus in the ACB group at 6 hours, there were no differences in opioid-related side effects. CONCLUSIONS: An ACB provides equivalent analgesia after medial UKA when compared with a PCB. In addition, the ACB caused significantly less motor weakness. An ACB should be considered for postoperative analgesia after medial UKA.

Evaluating residual anti-Xa levels following discontinuation of treatment-dose enoxaparin in patients presenting for elective surgery: a prospective observational trial.

INTRODUCTION: Prior studies have demonstrated that patients presenting for elective surgery may have higher-than-expected residual anti-Xa level activity at or beyond 24 hours following their last treatment dose of enoxaparin. Given that 24 hours of abstinence is currently recommended by both European and American societies before the performance of neuraxial or deep anesthetic/analgesic procedures, determining the actual timeframe at which residual anti-Xa level activity reliably falls below 0.2 IU/mL, the lower limit of the target range for thromboprophylaxis, is critical. METHODS: This was a prospective observational trial. Consenting patients on treatment-dose enoxaparin were randomized to either a 24-hour group (last dose at 07:00 the day prior to surgery) or a 36-hour group (last dose at 19:00 2 days prior to surgery). On arrival for surgery, blood samples were obtained to assess residual anti-Xa level activity and renal function. The primary outcome was residual anti-Xa level activity following the last treatment dose of enoxaparin. Incorporating all patients, linear regression modeling was performed to predict the timepoint at which the level of anti-Xa activity reliably fell below 0.2 IU/mL. RESULTS: 103 patients were analyzed. Time from the last dose at which residual anti-Xa activity fell below 0.2 IU/mL, based on the upper bound of the 95% CI, was 31.5 hours. No correlation overall between age, renal function, or sex was found. CONCLUSION: Residual levels of anti-Xa activity do not reliably fall below 0.2 IU/mL 24 hours following discontinuation of treatment-dose enoxaparin. Therefore, current time-based guidelines are not conservative enough. Routine anti-Xa testing should be strongly considered, or current time-based guidelines should be reassessed. TRIAL REGISTRATION NUMBER: NCT03296033.

Methylmercury accumulation in plankton on the continental margin of the northwest Atlantic Ocean.

Accumulation of monomethylmercury (MMHg) by plankton is a key process influencing concentrations of this toxic mercury species in marine food webs and seafood. We examined bioaccumulation and biomagnification of MMHg in microseston and four size fractions of zooplankton on the continental shelf, slope, and rise of the northwest Atlantic Ocean. The bioaccumulation factor (BAF, L/kg) for MMHg in microseston averaged 10(4.3±0.3) among 21 locations, and concentrations were unrelated to those in colocated, filtered surface water. Instead, concentrations and the BAF of MMHg in microseston were related inversely with total suspended solids in surface water, a proxy for planktonic biomass at these remote locations. MMHg was biomagnified by a factor of 4 from microseston to zooplankton, and both concentrations of MMHg and the fraction of total mercury as MMHg increased with larger size fractions of zooplankton. These results suggest that the initial magnitude of MMHg uptake into pelagic marine food webs is influenced by the degree of primary production in surface waters and propagated up through large zooplankton. Accordingly, biological productivity, in addition to inputs of MMHg to surface waters, must be considered when predicting how MMHg bioaccumulation will vary spatially and temporally in the ocean.

Randomized controlled trial of intrathecal oxytocin on speed of recovery after hip arthroplasty.

ABSTRACT: Recovery from surgery is quicker in the postpartum period, and this may reflect oxytocin action in the spinal cord. We hypothesized that intrathecal injection of oxytocin would speed recovery from pain and disability after major surgery. Ninety-eight individuals undergoing elective total hip arthroplasty were randomized to receive either intrathecal oxytocin (100 µg) or saline. Participants completed diaries assessing pain and opioid use daily and disability weekly, and they wore an accelerometer beginning 2 weeks before surgery until 8 weeks after. Groups were compared using modelled, adjusted trajectories of these measures. The study was stopped early due to the lack of funding. Ninety patients received intrathecal oxytocin (n = 44) or saline (n = 46) and were included in the analysis. There were no study drug-related adverse effects. Modelled pain trajectory, the primary analysis, did not differ between the groups, either in pain on day of hospital discharge (intercept: -0.1 [95% CI: -0.8 to 0.6], P = 0.746) or in reductions over time (slope: 0.1 pain units per log of time [95% CI: 0-0.2], P = 0.057). In planned secondary analyses, postoperative opioid use ended earlier in the oxytocin group and oxytocin-treated patients walked nearly 1000 more steps daily at 8 weeks ( P < 0.001) and exhibited a clinically meaningful reduction in disability for the first 21 postoperative days ( P = 0.007) compared with saline placebo. Intrathecal oxytocin before hip replacement surgery does not speed recovery from worst daily pain. Secondary analyses suggest that further study of intrathecal oxytocin to speed functional recovery without worsening pain after surgery is warranted.

Femoral nerve block with selective tibial nerve block provides effective analgesia without foot drop after total knee arthroplasty: a prospective, randomized, observer-blinded study.

BACKGROUND: Sciatic nerve block when combined with femoral nerve block for total knee arthroplasty may provide superior analgesia but can produce footdrop, which may mask surgically induced peroneal nerve injury. In this prospective, randomized, observer-blinded study, we evaluated whether performing a selective tibial nerve block in the popliteal fossa would avoid complete peroneal motor block. METHODS: Eighty patients scheduled for primary total knee arthroplasty were randomized to receive either a tibial nerve block in the popliteal fossa or a sciatic nerve block proximal to its bifurcation in combination with femoral nerve block as part of a multimodal analgesia regimen. Local anesthetic solution of sufficient volume to encircle the target nerve was administered for the block, up to a maximum of 20 mL. General anesthesia was administered for surgery. After emergence from anesthesia, in the recovery room, the presence or absence of peroneal sensory and motor block was noted. Pain scores and opioid consumption were recorded for 24 hours after surgery. RESULTS: The tibial nerve block and sciatic nerve block were performed 1.7 cm (99% CI, 1.3 to 2.1) and 9.4 cm (99% CI, 8.3 to 10.5) proximal to the popliteal crease, respectively (99% CI for difference between means: 6.4 to 9.0; P < 0.001). A lower volume of ropivacaine 0.5% was used for the tibial nerve block, 8.7 mL (99% CI, 7.9 to 9.4) versus 15.2 mL (99% CI, 14.9 to 15.5), respectively (99% CI for difference between means, 5.6 to 7.3; P < 0.001). No patient receiving a tibial nerve block developed complete peroneal motor block compared to 82.5% of patients with sciatic nerve block (P < 0.001). There were no significant differences in the pain scores and opioid consumption between the groups. CONCLUSIONS: Tibial nerve block performed in the popliteal fossa in close proximity to the popliteal crease avoided complete peroneal motor block and provided similar postoperative analgesia compared to sciatic nerve block when combined with femoral nerve block for patients undergoing total knee arthroplasty.

Surface Landmarks in the Lateral Decubitus Position Are Unreliable for Thoracic Epidural Catheter Placement: A Case Series.

Thoracic epidurals remain the optimal method for providing postoperative analgesia after complex open abdominal and thoracic surgeries. However, they can be challenging to both place and maintain, as evidenced by a failure rate that exceeds 30%.1 Proper identification of the epidural space and accurate placement of the catheter are critical in order to deliver effective postoperative analgesia and avoid failure.2,3 This case series investigated the difficulty in correctly identifying the proper vertebral level for thoracic epidural catheter procedures when performed in the lateral decubitus position.

Seasonal temperature variability observed at abyssal depths in the Arabian Sea.

The abyssal ocean is generally considered an aseasonal environment decoupled from the variabilities observed at and just below the ocean's surface. Herein, we describe the first in-situ timeseries record of seasonal warming and cooling in the Arabian Sea at a depth of 4000 m. The seasonal cycle was observed over the nearly four-year-long record (from November 2018 to March 2022). The abyssal seasonal temperature cycle also exhibited noticeable interannual variability. We investigate whether or not surface processes influence the near-seabed temperature through deep meridional overturning circulation modulated by the Indian monsoon or by Rossby wave propagation. We also consider if bottom water circulation variability and discharge of the dense Persian Gulf and Red Sea Water may contribute to the observed seasonality.

The role of α7-nicotinic acetylcholine receptor in a rat model of chronic nicotine-induced mechanical hypersensitivity.

Smokers have a higher incidence of chronic pain than non-smokers, but the neural mechanism is not yet fully understood. Nicotine is the main component of tobacco and acts as an agonist for nicotinic cholinergic receptors (nAChRs) in the nervous system. This study was approved by the IACUC of UM. The effects of chronic nicotine administration on mechanical sensitivity were studied using a rat model. The changes in the expression levels of the α7 isoform of nAChR (α7-nAChR), inflammatory cytokines TNFα and COX-2, as well as the density of neuro-immune cells (astrocytes and microglia) were measured concurrently. The results indicate that long-term nicotine administration induces hypersensitivity to mechanical stimuli, as demonstrated by a significant reduction in the pain perception threshold. In response to nicotine, the expression levels of α7-nAChR increased in the periaqueductal gray matter (PAG) and decreased in the spinal cord. Acute administration of the selective α7-nAChR agonist CDP-Choline reversed this hypersensitivity. Chronic nicotine administration led to an increase of microglial cells in the dorsal horn of the spinal cord and increased expression levels of the cytokines TNFα and COX-2. This study suggests that decreased α7-nAChR expression in the spinal cord, as a result of long-term exposure to nicotine, may be causatively linked to chronic pain. Simultaneously, the increase of neuro-immune factors in the spinal cord is also a potential factor leading to chronic pain.

The mechanism of chronic nicotine exposure and nicotine withdrawal on pain perception in an animal model.

It has been demonstrated that smoking is associated with an increase in postoperative and chronic pain. The changes in the pain-related neural pathways responsible for these effects are unknown. Additionally, the effects of nicotine withdrawal, resulting from smoking abstinence preoperatively, has not been evaluated in terms of its impact on pain sensation. In this study, an animal model has been used to assess these effects. A rat model of long-term nicotine exposure was used. Von Frey mechanical sensory tests were performed. Western Blot and immunohistological analysis were conducted on spinal cord samples. Mechanical sensory thresholds increased in the initial period (1-3 weeks), indicating hyposensitivity. Long-term (410 weeks) and under nicotine withdrawal, the mechanical sensory thresholds decreased, indicating hyperalgesia. During short-term nicotine exposure, glutamate decarboxylase 67 (GAD67), GAD65, and µ-opioid receptors (MOR) up-regulated. Beta-endorphins down-regulated. Increased γ -aminobutyric acid (GABA) and MOR appear responsible for the hyposensitivity since the GABA receptor antagonist, bicuculline and opioid receptor antagonist, naloxone decreased the mechanical thresholds of nicotine-induced hyposensitivity. In long-term nicotine exposure, the expression of GAD67, MOR, and GABA decreased. Baclofen, a derivative of GABA, reversed the hyperalgesia seen with nicotine withdrawal. Therefore, nicotine acts as an analgesic when used acutely or short-term. Long-term exposure or nicotine withdrawal (similar to smoking cessation) results in hyperalgesia. Nicotine appears to alter pain sensitivity by affecting the expression of GAD65, GAD67, MOR, endorphins, and GABA. This may partially explain the increased pain and opioid use seen in chronic smokers in the postoperative period.

Ilioinguinal/Iliohypogastric versus quadratus lumborum nerve blockade for elective open inguinal herniorrhaphy: a prospective, randomized, double-blinded, equivalency trial.

BACKGROUND: Open inguinal herniorrhaphy (OIH) is a commonly performed surgical procedure with expected postoperative pain. Historically, an option for regional analgesia has been an ilioinguinal and iliohypogastric nerve block (IINB). More recently, the transmuscular quadratus lumborum block (QLB) has been used as an analgesic technique for a variety of abdominal and truncal surgical procedures. Given our own institutional experiences with the performance of QLB combined with the body of literature supporting the proximal blockade of the ilioinguinal and iliohypogastric nerves via this approach, we compared the analgesia provided by an IINB to a QLB. We hypothesized that the two blocks would provide equivalent analgesia, as defined by a difference of less than±2 points on the pain scale (0-10 numeric rating scale (NRS)), for patients undergoing OIH. METHODS: Sixty patients scheduled for elective outpatient OIH under general anesthesia were randomized to preoperatively receive either an IINB or a transmuscular QLB with 0.25% bupivacaine/epinephrine/clonidine for postoperative analgesia. The primary endpoint was movement NRS pain scores at 8 hours. Secondary outcomes included resting NRS pain scores at 8 and 24 hours, movement NRS pain scores at 24 hours, incidence of opioid related side effects (nausea, vomiting, pruritus), time-to-first oral opioid analgesic, and total opioid consumption at 24 hours. RESULTS: Fifty-nine patients were analyzed per an intention-to-treat approach (one patient was excluded because the surgical procedure was canceled). Movement pain scores at 8 hours were equivalent (IINB 5.10±3.02 vs QLB 5.03±3.01 (mean NRS±SD); two one-sided test mean difference (90% CI), 0.07 (-1.24 to 1.38), p ≤0.01). There were no differences between groups for any of the secondary endpoints. CONCLUSION: An IINB and a transmuscular QLB are equivalent with regards to their ability to provide postoperative analgesia after OIH.

Postoperative ward monitoring - Why and what now?

The postoperative ward is considered an ideal nursing environment for stable patients transitioning out of the hospital. However, approximately half of all in-hospital cardiorespiratory arrests occur here and are associated with poor outcomes. Current monitoring practices on the hospital ward mandate intermittent vital sign checks. Subtle changes in vital signs often occur at least 8-12 h before an acute event, and continuous monitoring of vital signs would allow for effective therapeutic interventions and potentially avoid an imminent cardiorespiratory arrest event. It seems tempting to apply continuous monitoring to every patient on the ward, but inherent challenges such as artifacts and alarm fatigue need to be considered. This review looks to the future where a continuous, smarter, and portable platform for monitoring of vital signs on the hospital ward will be accompanied with a central monitoring platform and machine learning-based pattern detection solutions to improve safety for hospitalized patients.

The Land-Sea Breeze of the Red Sea: Observations, Simulations, and Relationships to Regional Moisture Transport.

Unique in situ observations of atmospheric conditions over the Red Sea and the coastal Arabian Peninsula are examined to study the dynamics and regional impacts of the local land-sea breeze cycle (LSBC). During a 26-month data record spanning 2008-2011, observed LSBC events occurred year-round, frequently exhibiting cross-shore wind velocities in excess of 8 m/s. Observed onshore and offshore features of both the land- and sea-breeze phases of the cycle are presented, and their seasonal modulation is considered. Weather Research and Forecasting climate downscaling simulations and satellite measurements are used to extend the analysis. In the model, the amplitude of the LSBC is significantly larger in the vicinity of the steeper terrain elements encircling the basin, suggesting an enhancement by the associated slope winds. Observed and simulated conditions also reflected distinct gravity-current characteristics of the intrinsic moist marine air mass during both phases of the LSBC. Specifically, the advance and retreat of marine air mass was directly tied to the development of internal boundary layers onshore and offshore throughout the period of study. Convergence in the lateral moisture flux resulting from this air mass ascending the coastal topography (sea-breeze phase) as well as colliding with air masses from the opposing coastline (land-breeze phase) further resulted in cumulous cloud formation and precipitation.