The latest medical research on Anesthesiology

The research magnet gathers the latest research from around the web, based on your specialty area. Below you will find a sample of some of the most recent articles from reputable medical journals about anesthesiology gathered by our medical AI research bot.

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Transversus Abdominis Plane Block: A Narrative Review.


In this narrative review article, the authors discuss the anatomy, nomenclature, history, approaches (posterior vs. lateral vs. subcostal), techniq...

Trends in Direct Hospital Payments to Anesthesia Groups: A Retrospective Cohort Study of Nonacademic Hospitals in California.


In the United States, anesthesia groups derive revenue from insurers and "direct payments" or "institutional support" from hospitalsDirect payments can represent a significant portion of group revenue and may enable the provision of services to patients covered by public insurers, which disproportionately represent low-resource and underserved populationsThe magnitude or characteristics of direct hospital payments to nonacademic private practice anesthesia groups is not well understood WHAT THIS ARTICLE TELLS US THAT IS NEW: Among 240 nonacademic California hospitals analyzed between 2002 and 2014, more hospitals made direct payments to an anesthesia group in 2014 than in 2002 and the median payment increasedHospitals where public insurers accounted for a larger fraction of anesthesia revenues were increasingly more likely to make direct payments to private anesthesia groupsDirect payments to private anesthesia groups are becoming increasingly important, particularly for hospitals providing care to underserved populations BACKGROUND:: In addition to payments for services, anesthesia groups in the United States often receive revenue from direct hospital payments. Understanding the magnitude of these payments and their association with the hospitals' payer mixes has important policy implications.

Using a dataset of financial reports from 240 nonacademic California hospitals between 2002 and 2014, the authors characterized the prevalence and magnitude of direct hospital payments to anesthesia groups, and analyzed the association between these payments and the fraction of anesthesia revenue derived from public payers (e.g., Medicaid).

Of hospitals analyzed, 69% (124 of 180) made direct payments to an anesthesia group in 2014, compared to 52% (76 of 147) in 2002; the median payment increased from $242,351 (mean, $578,322; interquartile range, $72,753 to $523,861; all dollar values in 2018 U.S. dollars) to $765,128 (mean, $1,295,369; interquartile range, $267,006 to $1,503,163) during this time period. After adjusting for relevant covariates, hospitals where public insurers accounted for a larger fraction of anesthesia revenues were more likely to make direct payments to anesthesia groups (β = 0.45; 95% CI, 0.10 to 0.81; P = 0.013), so that a 10-percentage point increase in the fraction of anesthesia revenue derived from public payers would be associated with a 4.5-percentage point increase in the probability of receiving any payment. Among hospitals making payments, our results (β = 2.10; 95% CI, 0.74 to 3.45; P = 0.003) suggest that a 1-percentage point increase in the fraction of anesthesia revenue derived from public payers would be associated with a 2% relative increase in the amount paid.

Direct payments from hospitals are becoming a larger financial consideration for anesthesia groups in California serving nonacademic hospitals, and are larger for groups working at hospitals serving publicly insured patients.

Superior Trunk Block: A Phrenic-sparing Alternative to the Interscalene Block: A Randomized Controlled Trial.


Interscalene nerve block is commonly used for shoulder surgery for anesthesia and postoperative analgesiaUnfortunately, interscalene blocks commonly result in hemidiaphragmatic paralysis WHAT THIS ARTICLE TELLS US THAT IS NEW: When interscalene block was compared with superior trunk block, less frequent hemidiaphragmatic paralysis was seen in the superior trunk block groupSuperior trunk block was noninferior to interscalene block in terms of worst pain scores in the recovery room, and superior trunk block patients were more satisfied BACKGROUND:: Interscalene nerve blockade remains one of the most commonly used anesthetic and analgesic approaches for shoulder surgery. The high incidence of hemidiaphragmatic paralysis associated with the block, however, precludes its use among patients with compromised pulmonary function. To address this issue, recent studies have investigated phrenic-sparing alternatives that provide analgesia. None, however, have been able to reliably demonstrate surgical anesthesia without significant risk for hemidiaphragmatic paralysis. The utility of the superior trunk block has yet to be studied. The hypothesis was that compared with the interscalene block, the superior trunk block will provide noninferior surgical anesthesia and analgesia while sparing the phrenic nerve.

This randomized controlled trial included 126 patients undergoing arthroscopic ambulatory shoulder surgery. Patients either received a superior trunk block (n = 63) or an interscalene block (n = 63). The primary outcomes were the incidence of hemidiaphragmatic paralysis and worst pain score in the recovery room. Ultrasound was used to assess for hemidiaphragmatic paralysis. Secondary outcomes included noninvasively measured parameters of respiratory function, opioid consumption, handgrip strength, adverse effects, and patient satisfaction.

The superior trunk group had a significantly lower incidence of hemidiaphragmatic paralysis compared with the interscalene group (3 of 62 [4.8%] vs. 45 of 63 [71.4%]; P < 0.001, adjusted odds ratio 0.02 [95% CI, 0.01, 0.07]), whereas the worst pain scores in the recovery room were noninferior (0 [0, 2] vs. 0 [0, 3]; P = 0.951). The superior trunk group were more satisfied, had unaffected respiratory parameters, and had a lower incidence of hoarseness. No difference in handgrip strength or opioid consumption were detected. Superior trunk block was associated with lower worst pain scores on postoperative day 1.

Compared with the interscalene block, the superior trunk block provides noninferior surgical anesthesia while preserving diaphragmatic function. The superior trunk block may therefore be considered an alternative to traditional interscalene block for shoulder surgery.

Measurement of extravascular lung water to diagnose severe reperfusion lung injury following pulmonary endarterectomy: a prospective cohort clinical validation study.


The measurement of extravascular lung water is a relatively new technology which has not yet been well validated as a clinically useful tool. We st...

A randomised controlled trial of the pectoral nerves-2 (PECS-2) block for radical mastectomy.


We randomly allocated 50 women scheduled for radical mastectomy to pectoral nerves-2 (PECS-2) block (n = 25) or no block (n = 25), 20 and 22 of who...

Blood Purification and Mortality in Sepsis and Septic Shock: A Systematic Review and Meta-analysis of Randomized Trials.


Among patients with sepsis or septic shock, a variety of extracorporeal blood purification techniques are availableIndividual existing trials evaluating these options are underpowered to provide clear evidence WHAT THIS PAPER TELLS US THAT IS NEW: Meta-analysis of very low-quality randomized controlled trial evidence demonstrates a potential benefit of hemoperfusion, hemofiltration, or plasmapheresisAdditional high-quality trials demonstrating benefit in modern clinical practice are needed before recommending these therapies BACKGROUND:: Sepsis and septic shock are severe inflammatory conditions related to high morbidity and mortality. We performed a systematic review with meta-analysis of randomized trials to assess whether extracorporeal blood purification reduces mortality in this setting.

Electronic databases were searched for pertinent studies up to January 2019. We included randomized controlled trials on the use of hemoperfusion, hemofiltration without a renal replacement purpose, and plasmapheresis as a blood purification technique in comparison to conventional therapy in adult patients with sepsis and septic shock. The primary outcome was mortality at the longest follow-up available. We calculated relative risks and 95% CIs. The grading of recommendations assessment, development and evaluation methodology for the certainty of evidence was used.

Thirty-seven trials with 2,499 patients were included in the meta-analysis. Hemoperfusion was associated with lower mortality compared to conventional therapy (relative risk = 0.88 [95% CI, 0.78 to 0.98], P = 0.02, very low certainty evidence). Low risk of bias trials on polymyxin B immobilized filter hemoperfusion showed no mortality difference versus control (relative risk = 1.14 [95% CI, 0.96 to 1.36], P = 0.12, moderate certainty evidence), while recent trials found an increased mortality (relative risk = 1.22 [95% CI, 1.03 to 1.45], P = 0.02, low certainty evidence); trials performed in the United States and Europe had no significant difference in mortality (relative risk = 1.13 [95% CI, 0.96 to 1.34], P = 0.15), while trials performed in Asia had a positive treatment effect (relative risk = 0.57 [95% CI, 0.47 to 0.69], P < 0.001). Hemofiltration (relative risk = 0.79 [95% CI, 0.63 to 1.00], P = 0.05, very low certainty evidence) and plasmapheresis (relative risk = 0.63 [95% CI, 0.42 to 0.96], P = 0.03, very low certainty evidence) were associated with a lower mortality.

Very low-quality randomized evidence demonstrates that the use of hemoperfusion, hemofiltration, or plasmapheresis may reduce mortality in sepsis or septic shock. Existing evidence of moderate quality and certainty does not provide any support for a difference in mortality using polymyxin B hemoperfusion. Further high-quality randomized trials are needed before systematic implementation of these therapies in clinical practice.

Prophylactic Haloperidol Effects on Long-term Quality of Life in Critically Ill Patients at High Risk for Delirium: Results of the REDUCE Study.


Delirium is a frequently occurring disorder in intensive care unit patients associated with impaired short-term and long-term outcomesProphylactic haloperidol neither reduces delirium incidence nor its short-term clinical consequencesMany intensive care unit survivors suffer from long-term impairment of physical, cognitive, or mental health status, but there is a gap in knowledge regarding which factors are associated with such a change in quality of life in the post-intensive care unit period WHAT THIS ARTICLE TELLS US THAT IS NEW: Prophylactic haloperidol does not affect long-term outcome of critically ill patients at high risk for deliriumEvery additional day of sedation-induced coma is associated with further decline of long-term physical and mental function BACKGROUND:: Delirium incidence in intensive care unit patients is high and associated with impaired long-term outcomes. The use of prophylactic haloperidol did not improve short-term outcome among critically ill adults at high risk of delirium. This study evaluated the effects of prophylactic haloperidol use on long-term quality of life in this group of patients and explored which factors are associated with change in quality of life.

A preplanned secondary analysis of long-term outcomes of the pRophylactic haloperidol usE for DeliriUm in iCu patients at high risk for dElirium (REDUCE) study was conducted. In this multicenter randomized clinical trial, nondelirious intensive care unit patients were assigned to prophylactic haloperidol (1 or 2 mg) or placebo (0.9% sodium chloride). In all groups, patients finally received study medication for median duration of 3 days [interquartile range, 2 to 6] until onset of delirium or until intensive care unit discharge. Long-term outcomes were assessed using the Short Form-12 questionnaire at intensive care unit admission (baseline) and after 1 and 6 months. Quality of life was summarized in the physical component summary and mental component summary scores. Differences between the haloperidol and placebo group and factors associated with changes in quality of life were analyzed.

Of 1,789 study patients, 1,245 intensive care unit patients were approached, of which 887 (71%) responded. Long-term quality of life did not differ between the haloperidol and placebo group (physical component summary mean score of 39 ± 11 and 39 ± 11, respectively, and P = 0.350; and mental component summary score of 50 ± 10 and 51 ± 10, respectively, and P = 0.678). Age, medical and trauma admission, quality of life score at baseline, risk for delirium (PRE-DELIRIC) score, and the number of sedation-induced coma days were significantly associated with a decline in long-term quality of life.

Prophylactic haloperidol use does not affect long-term quality of life in critically ill patients at high risk for delirium. Several factors, including the modifiable factor number of sedation-induced coma days, are associated with decline in long-term outcomes.

Population Kinetics of 0.9% Saline Distribution in Hemorrhaged Awake and Isoflurane-anesthetized Volunteers.


Volume kinetic modeling is an adaptation of pharmacokinetic modeling that characterizes the disposition of intravenously administered fluids using hemoglobin concentration as a natural tracerPopulation-based pharmacokinetic analysis enables assessment of variability between individuals and across populations and permits inclusion of covariates such as the presence or absence of anesthetization, body weight, and sex in the data analysis WHAT THIS ARTICLE TELLS US THAT IS NEW: The distribution of infused fluid after hemorrhage (7 ml/kg during 20 min) in a randomized crossover study of 12 healthy volunteers while awake and while isoflurane-anesthetized was described by a two-fluid space model that included study arm, body weight, and sex as covariatesOnly sex had a statistically significant effect on the area under the plasma dilution curve and maximum plasma dilution, both of which were increased by a median of 17% in females (95% CIs, 1.08 to 1.38 and 1.07 to 1.39, respectively) compared with males BACKGROUND:: Population-based, pharmacokinetic modeling can be used to describe variability in fluid distribution and dilution between individuals and across populations. The authors hypothesized that dilution produced by crystalloid infusion after hemorrhage would be larger in anesthetized than in awake subjects and that population kinetic modeling would identify differences in covariates.

Twelve healthy volunteers, seven females and five males, mean age 28 ± 4.3 yr, underwent a randomized crossover study. Each subject participated in two separate sessions, separated by four weeks, in which they were assigned to an awake or an anesthetized arm. After a baseline period, hemorrhage (7 ml/kg during 20 min) was induced, immediately followed by a 25 ml/kg infusion during 20 min of 0.9% saline. Hemoglobin concentrations, sampled every 5 min for 60 min then every 10 min for an additional 120 min, were used for population kinetic modeling. Covariates, including body weight, sex, and study arm (awake or anesthetized), were tested in the model building. The change in dilution was studied by analyzing area under the curve and maximum plasma dilution.

Anesthetized subjects had larger plasma dilution than awake subjects. The analysis showed that females increased area under the curve and maximum plasma dilution by 17% (with 95% CI, 1.08 to 1.38 and 1.07 to 1.39) compared with men, and study arm (anesthetized increased area under the curve by 99% [0.88 to 2.45] and maximum plasma dilution by 35% [0.71 to 1.63]) impacted the plasma dilution whereas a 10-kg increase of body weight resulted in a small change (less than1% [0.93 to 1.20]) in area under the curve and maximum plasma dilution. Mean arterial pressure was lower in subjects while anesthetized (P < 0.001).

In awake and anesthetized subjects subjected to controlled hemorrhage, plasma dilution increased with anesthesia, female sex, and lower body weight. Neither study arm nor body weight impact on area under the curve or maximum plasma dilution were statistically significant and therefore no effect can be established.

Opioid- and Motor-sparing with Proximal, Mid-, and Distal Locations for Adductor Canal Block in Anterior Cruciate Ligament Reconstruction: A Randomized Clinical Trial.


Adductor canal nerve block is useful for a range of knee surgeries, although the optimal injection location has not been definedUnfortunately, analgesia achieved using adductor canal block is sometimes accompanied by unwanted motor block WHAT THIS ARTICLE TELLS US THAT IS NEW: Proximal adductor canal injections were associated with lower first 24-h morphine consumption than when injections were more distalDecreases in quadriceps strength were similar whether the injection was made in a proximal, mid-, or distal adductor canal location BACKGROUND:: The ideal location for single-injection adductor canal block that maximizes analgesia while minimizing quadriceps weakness after painful knee surgery is unclear. This triple-blind trial compares ultrasound-guided adductor canal block injection locations with the femoral artery positioned medial (proximal adductor canal), inferior (mid-adductor canal), and lateral (distal adductor canal) to the sartorius muscle to determine the location that optimizes postoperative analgesia and motor function. The hypothesis was that distal adductor block has (1) a superior opioid-sparing effect and (2) preserved quadriceps strength, compared with proximal and mid-locations for anterior cruciate ligament reconstruction.

For the study, 108 patients were randomized to proximal, mid-, or distal adductor canal injection locations for adductor canal block. Cumulative 24-h oral morphine equivalent consumption and percentage quadriceps strength decrease (maximum voluntary isometric contraction) at 30 min postinjection were coprimary outcomes. The time to first analgesic request, pain scores, postoperative nausea/vomiting at least once within the first 24 h, and block-related complications at 2 weeks were also evaluated.

All patients completed the study. Contrary to the hypothesis, proximal adductor canal block decreased 24-h morphine consumption to a mean ± SD of 34.3 ± 19.1 mg, (P < 0.0001) compared to 64.0 ± 33.6 and 65.7 ± 22.9 mg for the mid- and distal locations, respectively, with differences [95% CI] of 29.7 mg [17.2, 42.2] and 31.4 mg [21.5, 41.3], respectively, mostly in the postanesthesia care unit. Quadriceps strength was similar, with 16.7%:13.4%:15.3% decreases for proximal:mid:distal adductor canal blocks. The nausea/vomiting risk was also lower with proximal adductor canal block (10 of 34, 29.4%) compared to distal location (23 of 36, 63.9%; P = 0.005). The time to first analgesic request was longer, and postoperative pain was improved up to 6 h for proximal adductor canal block, compared to mid- and distal locations.

A proximal adductor canal injection location decreases opioid consumption and opioid-related side effects without compromising quadriceps strength compared to mid- and distal locations for adductor canal block in patients undergoing anterior cruciate ligament reconstruction.

Preadmission Statin Use and 90-day Mortality in the Critically Ill: A Retrospective Association Study.


Randomized controlled trials evaluating the potential value of statin administration for intensive care unit patients have not observed a benefitHowever, the chronic preadmission use of statins among patients admitted to the intensive care unit has not been robustly studied WHAT THIS ARTICLE TELLS US THAT IS NEW: Single-center retrospective data suggest that preadmission statin use may be associated with decreased 90-day mortality among some intensive care unit patientsSpecific statin agents and noncardiovascular mortality may demonstrate a stronger signal for further study BACKGROUND:: This study aimed to examine the association between preadmission statin use and 90-day mortality in critically ill patients and to investigate whether this association differed according to statin type and dose. We hypothesized that preadmission statin use was associated with lower 90-day mortality.

This retrospective cohort study analyzed the medical records of all adult patients admitted to the intensive care unit in a single tertiary academic hospital between January 2012 and December 2017. Data including preadmission statin use, statin subtype, and daily dosage were collected, and the associations between these variables and 90-day mortality after intensive care unit admission were examined. The primary endpoint was 90-day mortality.

A total of 24,928 patients (7,396 statin users and 17,532 non-statin users) were included. After propensity score matching, 5,354 statin users and 7,758 non-statin users were finally included. The 90-day mortality rate was significantly higher in non-statin users (918 of 7,758; 11.8%) than in statin users (455 of 5,354; 8.5%; P < 0.001). In Cox regression analysis, the 90-day mortality rate was lower among statin users than among non-statin users (hazard ratio: 0.70, 95% CI: 0.63 to 0.79; P < 0.001). Rosuvastatin use was associated with 42% lower 90-day mortality (hazard ratio: 0.58, 95% CI: 0.47 to 0.72; P < 0.001). There were no specific significant differences in the association between daily statin dose and 90-day mortality. In competing risk analysis, the risk of noncardiovascular 90-day mortality in statin users was 32% lower than that in non-statin users (hazard ratio: 0.68, 95% CI: 0.60 to 0.78; P < 0.001). Meanwhile, cardiovascular 90-day mortality was not significantly associated with statin use.

Preadmission statin use was associated with a lower 90-day mortality. This association was more evident in the rosuvastatin group and with noncardiovascular 90-day mortality; no differences were seen according to daily dosage intensity.

Internal Carotid Artery Blood Flow Response to Anesthesia, Pneumoperitoneum, and Head-up Tilt during Laparoscopic Cholecystectomy.


Cardiac output is an independent regulator of cerebral blood flow in healthy awake humansThe relationship between cardiac output and cerebral blood flow in anesthetized patients undergoing laparoscopy has not been previously characterized WHAT THIS ARTICLE TELLS US THAT IS NEW: At steady-state depth of anesthesia, in patients undergoing laparoscopic cholecystectomy, creation of pneumoperitoneum decreased cardiac output and internal carotid artery blood flow while mean arterial pressure and end-tidal carbon dioxide levels remained unchanged BACKGROUND:: Little is known about how implementation of pneumoperitoneum and head-up tilt position contributes to general anesthesia-induced decrease in cerebral blood flow in humans. We investigated this question in patients undergoing laparoscopic cholecystectomy, hypothesizing that cardiorespiratory changes during this procedure would reduce cerebral perfusion.

In a nonrandomized, observational study of 16 patients (American Society of Anesthesiologists physical status I or II) undergoing laparoscopic cholecystectomy, internal carotid artery blood velocity was measured by Doppler ultrasound at four time points: awake, after anesthesia induction, after induction of pneumoperitoneum, and after head-up tilt. Vessel diameter was obtained each time, and internal carotid artery blood flow, the main outcome variable, was calculated. The authors recorded pulse contour estimated mean arterial blood pressure (MAP), heart rate (HR), stroke volume (SV) index, cardiac index, end-tidal carbon dioxide (ETCO2), bispectral index, and ventilator settings. Results are medians (95% CI).

Internal carotid artery blood flow decreased upon anesthesia induction from 350 ml/min (273 to 410) to 213 ml/min (175 to 249; -37%, P < 0.001), and tended to decrease further with pneumoperitoneum (178 ml/min [127 to 208], -15%, P = 0.026). Tilt induced no further change (171 ml/min [134 to 205]). ETCO2 and bispectral index were unchanged after induction. MAP decreased with anesthesia, from 102 (91 to 108) to 72 (65 to 76) mmHg, and then remained unchanged (Pneumoperitoneum: 70 [63 to 75]; Tilt: 74 [66 to 78]). Cardiac index decreased with anesthesia and with pneumoperitoneum (overall from 3.2 [2.7 to 3.5] to 2.3 [1.9 to 2.5] l · min · m); tilt induced no further change (2.1 [1.8 to 2.3]). Multiple regression analysis attributed the fall in internal carotid artery blood flow to reduced cardiac index (both HR and SV index contributing) and MAP (P < 0.001). Vessel diameter also declined (P < 0.01).

During laparoscopic cholecystectomy, internal carotid artery blood flow declined with anesthesia and with pneumoperitoneum, in close association with reductions in cardiac index and MAP. Head-up tilt caused no further reduction. Cardiac output independently affects human cerebral blood flow.

Complications related to peri-operative transoesophageal echocardiography - a one-year prospective national audit by the Association of Cardiothoracic Anaesthesia and Critical Care.


Previous studies on the safety of peri-operative transoesophageal echocardiography seem to suggest a low rate of associated morbidity and mortality...