Effect of active forced air warming during the first hour after anesthesia induction and intraoperation avoids hypothermia in elderly patients.

BACKGROUND: The study aimed at exploring an optimal temperature model of forced air warming during the first hour after induction and intraoperation to prevent hyperthermia for elderly patients undergoing laparoscopic abdominal surgery. METHODS: There were 218 patients that were randomly divided into 3 groups warmed with a forced-air warmer during surgery: Group L (intraoperative warming set to 38 °C, n = 63), Group H (intraoperative warming set to 42 °C, n = 65) and Group LH (intraoperative warming set to 42 °C for the first hour then set to 38 °C, n = 65). Core temperature in the preoperative room and PACU was measured by a tympanic membrane thermometer and in the operation room, a nasopharyngeal temperature probe was recorded. The rate of perioperative hypothermia, defined as a reduction in body temperature to < 36 °C was recorded as the primary outcome. Intraoperative anesthetic dosage, recovery time, adverse events, thermal comfort and satisfaction score were measured as secondary outcome. RESULTS: The incidence of intraoperative and postoperative hypothermia was significantly lower in Group LH and Group H than Group L (18.75 and 15.62% vs 44.44%, P<0.001; 4.69 and 4.69% vs 20.63%, P<.05). Anesthetic dosage of rocuronium was lower in Group L than other two groups, with the opposite result of recovery time. The number of patients with shivering was higher in Group L but sweating was higher in Group H. Both of the thermal comfort and satisfaction score was highest in Group LH. CONCLUSION: A temperature pattern of forced air warming set at 42 °C during the first hour after anesthesia induction and maintained with 38 °C was a suitable choice for elderly patients undergoing laparoscopic abdominal surgery lasting for more than 120 min. TRIAL REGISTRATION: Chictr.org.cn ChiCTR-2,100,053,211.

Perioperative Pulmonary Atelectasis: Part II. Clinical Implications.

The development of pulmonary atelectasis is common in the surgical patient. Pulmonary atelectasis can cause various degrees of gas exchange and respiratory mechanics impairment during and after surgery. In its most serious presentations, lung collapse could contribute to postoperative respiratory insufficiency, pneumonia, and worse overall clinical outcomes. A specific risk assessment is critical to allow clinicians to optimally choose the anesthetic technique, prepare appropriate monitoring, adapt the perioperative plan, and ensure the patient's safety. Bedside diagnosis and management have benefited from recent imaging advancements such as lung ultrasound and electrical impedance tomography, and monitoring such as esophageal manometry. Therapeutic management includes a broad range of interventions aimed at promoting lung recruitment. During general anesthesia, these strategies have consistently demonstrated their effectiveness in improving intraoperative oxygenation and respiratory compliance. Yet these same intraoperative strategies may fail to affect additional postoperative pulmonary outcomes. Specific attention to the postoperative period may be key for such outcome impact of lung expansion. Interventions such as noninvasive positive pressure ventilatory support may be beneficial in specific patients at high risk for pulmonary atelectasis (e.g., obese) or those with clinical presentations consistent with lung collapse (e.g., postoperative hypoxemia after abdominal and cardiothoracic surgeries). Preoperative interventions may open new opportunities to minimize perioperative lung collapse and prevent pulmonary complications. Knowledge of pathophysiologic mechanisms of atelectasis and their consequences in the healthy and diseased lung should provide the basis for current practice and help to stratify and match the intensity of selected interventions to clinical conditions.

Intraoperative Hypotension and Acute Kidney Injury after Noncardiac Surgery in Infants and Children: A Retrospective Cohort Analysis.

BACKGROUND: Age- and sex-specific reference nomograms for intraoperative blood pressure have been published, but they do not identify harm thresholds. The authors therefore assessed the relationship between various absolute and relative characterizations of hypotension and acute kidney injury in children having noncardiac surgery. METHODS: The authors conducted a retrospective cohort study using electronic data from two tertiary care centers. They included inpatients 18 yr or younger who had noncardiac surgery with general anesthesia. Postoperative renal injury was defined using the Kidney Disease Improving Global Outcomes definitions, based on serum creatinine concentrations. The authors evaluated potential renal harm thresholds for absolute lowest intraoperative mean arterial pressure (MAP) or largest MAP reduction from baseline maintained for a cumulative period of 5 min. Separate analyses were performed in children aged 2 yr or younger, 2 to 6 yr, 6 to 12 yr, and 12 to 18 yr. RESULTS: Among 64,412 children who had noncardiac surgery, 4,506 had creatinine assessed preoperatively and postoperatively. The incidence of acute kidney injury in this population was 11% (499 of 4,506): 17% in children under 6 yr old, 11% in children 6 to 12 yr old, and 6% in adolescents, which is similar to the incidence reported in adults. There was no association between lowest cumulative MAP sustained for 5 min and postoperative kidney injury. Similarly, there was no association between largest cumulative percentage MAP reduction and postoperative kidney injury. The adjusted estimated odds for kidney injury was 0.99 (95% CI, 0.94 to 1.05) for each 5-mmHg decrease in lowest MAP and 1.00 (95% CI, 0.97 to 1.03) for each 5% decrease in largest MAP reduction from baseline. CONCLUSIONS: In distinct contrast to adults, the authors did not find any association between intraoperative hypotension and postoperative renal injury. Avoiding short periods of hypotension should not be the clinician's primary concern when trying to prevent intraoperative renal injury in pediatric patients.

Perioperative Pulmonary Atelectasis: Part I. Biology and Mechanisms.

Pulmonary atelectasis is common in the perioperative period. Physiologically, it is produced when collapsing forces derived from positive pleural pressure and surface tension overcome expanding forces from alveolar pressure and parenchymal tethering. Atelectasis impairs blood oxygenation and reduces lung compliance. It is increasingly recognized that it can also induce local tissue biologic responses, such as inflammation, local immune dysfunction, and damage of the alveolar-capillary barrier, with potential loss of lung fluid clearance, increased lung protein permeability, and susceptibility to infection, factors that can initiate or exaggerate lung injury. Mechanical ventilation of a heterogeneously aerated lung (e.g., in the presence of atelectatic lung tissue) involves biomechanical processes that may precipitate further lung damage: concentration of mechanical forces, propagation of gas-liquid interfaces, and remote overdistension. Knowledge of such pathophysiologic mechanisms of atelectasis and their consequences in the healthy and diseased lung should guide optimal clinical management.

C5 Palsy Following Cervical Spine Decompression.

BACKGROUND: Cervical spinal surgery is considered safe and effective. One of the few specific complications of this procedure is C5 nerve root palsy. Expressed primarily by deltoid muscle and biceps brachii weakness, it is rare and has been related to nerve root traction or to ischemic spinal cord damage. OBJECTIVES: To determine the clinical and epidemiological traits of C5 palsy. To determine whether C5 palsy occurs predominantly in one specific surgical approach compared to others. METHODS: A retrospective study of patients who underwent cervical spine surgery at our medical center during a consecutive 8-year period was conducted. The patient data were analyzed for demographics, diagnosis, and surgery type and approach, as well as for complications, with emphasis on the C5 nerve root palsy. RESULTS: The study group was comprised of 124 patients. Seven (5.6%) developed a C5 palsy following surgery. Interventions were either by anterior, by posterior or by a combined approach. Seven patients developed this complication. All of whom had myelopathy and were older males. A combined anteroposterior (5 patients) and posterior access (2 patients) were the only approaches that were associated with the C5 palsy. None of the patients who were operated via an anterior approach did develop this sequel. CONCLUSIONS: The incidence of the C5 root palsy in our cohort reached 5.6%. Interventions performed through a combined anterior-posterior access in older myelopathic males, may carry the highest risk for this complication.

Heterogeneous impact of hypotension on organ perfusion and outcomes: a narrative review.

Arterial blood pressure is the driving force for organ perfusion. Although hypotension is common in acute care, there is a lack of accepted criteria for its definition. Most practitioners regard hypotension as undesirable even in situations that pose no immediate threat to life, but hypotension does not always lead to unfavourable outcomes based on experience and evidence. Thus efforts are needed to better understand the causes, consequences, and treatments of hypotension. This narrative review focuses on the heterogeneous underlying pathophysiological bases of hypotension and their impact on organ perfusion and patient outcomes. We propose the iso-pressure curve with hypotension and hypertension zones as a way to visualize changes in blood pressure. We also propose a haemodynamic pyramid and a pressure-output-resistance triangle to facilitate understanding of why hypotension can have different pathophysiological mechanisms and end-organ effects. We emphasise that hypotension does not always lead to organ hypoperfusion; to the contrary, hypotension may preserve or even increase organ perfusion depending on the relative changes in perfusion pressure and regional vascular resistance and the status of blood pressure autoregulation. Evidence from RCTs does not support the notion that a higher arterial blood pressure target always leads to improved outcomes. Management of blood pressure is not about maintaining a prespecified value, but rather involves ensuring organ perfusion without undue stress on the cardiovascular system.

Circulating adrenomedullin and B-type natriuretic peptide do not predict blood pressure fluctuations during pheochromocytoma resection: a cross-sectional study.

BACKGROUND: Despite adequate presurgical management, blood pressure fluctuations are common during resection of pheochromocytoma or sympathetic paraganglioma (PPGL). To a large extent, the variability in blood pressure control during PPGL resection remains unexplained. Adrenomedullin and B-type natriuretic peptide, measured as MR-proADM and NT-proBNP, respectively, are circulating biomarkers of cardiovascular dysfunction. We investigated whether plasma levels of MR-proADM and NT-proBNP are associated with blood pressure fluctuations during PPGL resection. METHODS: Study subjects participated in PRESCRIPT, a randomized controlled trial in patients undergoing PPGL resection. MR-proADM and NT-proBNP were determined in a single plasma sample drawn before surgery. Multivariable linear and logistic regression analyses were used to explore associations between these biomarkers and blood pressure fluctuations, use of vasoconstrictive agents during surgery as well as the occurrence of perioperative cardiovascular events. RESULTS: A total of 126 PPGL patients were included. Median plasma concentrations of MR-proADM and NT-proBNP were 0.51 (0.41-0.63) nmol/L and 68.7 (27.9-150.4) ng/L, respectively. Neither MR-proADM nor NT-proBNP were associated with blood pressure fluctuations. There was a positive correlation between MR-proADM concentration and the cumulative dose of vasoconstrictive agents (03B2 0.44, P =0.001). Both MR-proADM and NT-proBNP were significantly associated with perioperative cardiovascular events (OR: 5.46, P =0.013 and OR: 1.54, P =0.017, respectively). CONCLUSIONS: plasma MR-proADM or NT-proBNP should not be considered as biomarkers for the presurgical risk assessment of blood pressure fluctuations during PPGL resection. Future studies are needed to explore the potential influence of these biomarkers on the intraoperative requirement of vasoconstrictive agents and the perioperative cardiovascular risk.

Transgastric Abdominal Ultrasonography in Anesthesia and Critical Care: Review and Proposed Approach.

The use of transesophageal echocardiography (TEE) in the operating room and intensive care unit can provide invaluable information on cardiac as well as abdominal organ structures and function. This approach may be particularly useful when the transabdominal ultrasound examination is not possible during intraoperative procedures or for anatomical reasons. This review explores the role of transgastric abdominal ultrasonography (TGAUS) in perioperative medicine. We describe several reported applications using 10 views that can be used in the diagnosis of relevant abdominal conditions associated with organ dysfunction and hemodynamic instability in the operating room and the intensive care unit.

Pulmonary Apical Cap as a Potential Risk Factor for Pleuroparenchymal Fibroelastosis.

Pleuroparenchymal fibroelastosis (PPFE) is a progressive and frequently fatal interstitial lung disease that involves the upper lobes. Although its cause remains unknown, the histopathologic evidence underlying PPFE bears striking resemblance to that of the pulmonary apical cap (PAC), a relatively common and benign entity. We describe the case of a patient with PAC that evolved into distinctly asymmetric PPFE over 6 years after unilateral surgical lung injury. Given the histologic similarity between these two conditions, we propose that these two entities underlie common biologic pathways of abnormal response to lung injury, with the presence of a PAC increasing susceptibility to the development of PPFE in the face of ongoing inflammatory insults. This case describes the histopathologic evolution of PAC to PPFE before and after an inciting injury.

Gastric content and perioperative pulmonary aspiration in patients with diabetes mellitus: a scoping review.

BACKGROUND: Gastric emptying may be delayed in patients with diabetes mellitus (DM). However, the incidence of full stomach in fasting patients with DM and their risk of pulmonary aspiration under anaesthesia is not well understood. METHODS: A scoping review was undertaken to map the literature on aspiration risk in DM. A search was conducted in seven bibliographic databases, including MEDLINE and Embase, for original articles that studied aspiration risk, gastric emptying, or gastric content and volume. Selection and characterisation were performed by two independent reviewers using a predefined protocol registered externally. RESULTS: The search identified 5063 unique records, and 16 studies (totalling 775 patients with DM) were selected: nine studied gastric emptying and seven studied gastric content or volume. There were no studies reporting the incidence of aspiration in subjects with DM. All nine studies reported delayed emptying in patients with DM compared with healthy controls. Amongst the seven studies that compared gastric residual content/volume (GRV) in the perioperative period, five reported clinically negligible GRV in both patients with DM and controls, whereas two observed a higher incidence of 'full' stomach in patients with DM. CONCLUSIONS: The evidence concerning the aspiration risk for surgical patients with DM is based on a limited number of studies, mostly unblinded, reporting physiological data on gastric emptying and gastric volume as surrogate markers of aspiration risk. Data on fasting gastric content and volume in patients with DM are limited and contradictory; hence, the true risk of aspiration in fasting patients with DM is unknown.

Hypotony Without Globe Rupture During Orbital Fracture Repair.

A 29-year-old male presented to the emergency department with an orbital fracture. He denied ocular symptoms and CT showed bilateral fracture of nasal bones, left medial orbital wall, and left orbital floor, with herniation of orbital fat and minimal retrobulbar hematoma. Pre-operative ophthalmic exam was unremarkable. Intra-operatively, intraocular pressure of the left eye was 5 mm Hg, a significant change from 17 mm Hg preoperatively. Globe exploration revealed no injury. Post-operatively, IOP normalized. With these findings it was felt that ocular manipulation related to the orbital fracture repair placed significant and intermittent pressure on the globe, thereby lowering IOP. Laryngoscope, 131:2238-2240, 2021.

Anesthetic protocol for right ventricular dysfunction management in heart transplantation: systematic review, development and validation.

BACKGROUND: Right Ventricular Dysfunction (RVD) is the most frequent intraoperative hemodynamic complication in Heart Transplantation (HTx). RVD occurs in 0.04-1.0% of cardiac surgeries with cardiotomy and in 20-50% of HTx, with mortality up to 75%. No consensus has been established for how anesthesiologists should manage RVD, with management methods many times remaining unvalidated. METHODS: We conducted a systematic review, following PRISMA guidelines, to create an anesthetic protocol to manage RVD in HTx, using databases that include PubMed and Embase, until September 2018 based on inclusion and exclusion criteria. The articles screening for the systematic review were done two independent reviewers, in case of discrepancy, we consulted a third independent reviewer. Based on the systematic review, the anesthetic protocol was developed. The instrument selected to perform the validation of the protocol was AGREE II, for this purpose expert anesthetists were recruited to do this process. The minimum arbitration score for domains validation cutoff of AGREE II is arbitered to 70%. This study was registered at PROSPERO (115600). RESULTS: In the systematic review, 152 articles were included. We present the protocol in a flowchart with six steps based on goal-directed therapy, invasive monitoring, and transesophageal echocardiogram. Six experts judged the protocol and validated it. CONCLUSION: The protocol has been validated by experts and new studies are needed to assess its applicability and potential benefits on major endpoints.

Hemodynamic Instability During Liver Transplantation in Patients With End-stage Liver Disease: A Consensus Document from ILTS, LICAGE, and SATA.

Hemodynamic instability (HDI) during liver transplantation (LT) can be difficult to manage and increases postoperative morbidity and mortality. In addition to surgical causes of HDI, patient- and graft-related factors are also important. Nitric oxide-mediated vasodilatation is a common denominator associated with end-stage liver disease related to HDI. Despite intense investigation, optimal management strategies remain elusive. In this consensus article, experts from the International Liver Transplantation Society, the Liver Intensive Care Group of Europe, and the Society for the Advancement of Transplant Anesthesia performed a rigorous review of the most current literature regarding the epidemiology, causes, and management of HDI during LT. Special attention has been paid to unique LT-associated conditions including the causes and management of vasoplegic syndrome, cardiomyopathies, LT-related arrhythmias, right and left ventricular dysfunction, and the specifics of medical and fluid management in end-stage liver disease as well as problems specifically related to portal circulation. When possible, management recommendations are made.

Intraoperative Hypotension and Myocardial Infarction Development Among High-Risk Patients Undergoing Noncardiac Surgery: A Nested Case-Control Study.

BACKGROUND: Hemodynamic instability during anesthesia and surgery is common and associated with cardiac morbidity and mortality. Information is needed regarding optimal blood pressure (BP) threshold in the perioperative period. Therefore, the effect of intraoperative hypotension (IOH) on risk of perioperative myocardial infarction (MI) was explored. METHODS: A nested case-control study with patients developing MI <30 days postsurgery matched with non-MI patients, sampled from a large surgery cohort. Study participants were adults undergoing noncardiac surgery at 3 university hospitals in Sweden, 2007-2014. Matching criteria were age, sex, American Society of Anesthesiologists (ASA) physical status, cardiovascular disease, hospital, year-, type-, and extent of surgery. Medical records were reviewed to validate MI diagnoses and retrieve information on comorbid history, baseline BP, laboratory and intraoperative data. Main exposure was IOH, defined as a decrease in systolic blood pressure (SBP), in mm Hg, from preoperative individual resting baseline lasting at least 5 minutes. Outcomes were acute MI, fulfilling the universal criteria, subclassified as type 1 and 2, occurring within 30 days and mortality beyond 30 days among case and control patients. Conditional logistic regression assessed the association between IOH, decrease in SBP from individual baseline, and perioperative MI. Mortality rates were estimated using Cox proportional hazards. Relative risk estimates are reported as are the corresponding absolute risks derived from the well-characterized source population. RESULTS: A total of 326 cases met the inclusion criteria and were successfully matched with 326 controls. The distribution of MI type was 59 (18%) type 1 and 267 (82%) type 2. Median time to MI diagnosis was 2 days; 75% were detected within a week of surgery. Multivariable analysis acknowledged IOH as an independent risk factor of perioperative MI. IOH, with reduction of 41-50 mm Hg, from individual baseline SBP, was associated with a more than tripled increased odds, odds ratio (OR) = 3.42 (95% confidence interval [CI], 1.13-10.3), and a hypotensive event >50 mm Hg with considerably increased odds in respect to MI risk, OR = 22.6, (95% CI, 7.69-66.2). In patients with a very high-risk burden, the absolute risk of an MI diagnosis increased from 3.6 to 68 per 1000 surgeries. CONCLUSIONS: In patients undergoing noncardiac surgery, IOH is a possible contributor to clinically significant perioperative MI. The high absolute MI risk associated with IOH, among a growing population of patients with a high-risk burden, suggests that increased vigilance of BP control in these patients may be beneficial.

Visual outcomes of lens subluxation surgery with Cionni modified capsular tension rings in Marfan syndrome.

Marfan syndrome (MFS) is a hereditary disease with an incidence of 0.3% in the general population. Approximately 60% of MFS patients with FBN1 gene mutation will suffer ectopia lentis (EL) from the age of 3. With the development of EL, severe loss of vision will accrue because of lens tilt and glaucoma. Cionni modified capsular tension rings (MCTR) has been applied in the surgery for EL in MFS patients. To evaluate visual acuity and safety of using MCTR during lens subluxation surgery in MFS patients, 66 MFS patients (110 eyes) were included in our study, with the mean duration of follow-up of 4.7 months (SD 1.76 months). The capsular bags were preserved in 101 eyes (91.81%) with MCTR implantation. There was an overall significant improvement in BCVA at 1-month follow-up which was maintained at 3 months. Multivariable linear regression revealed that older age at first visit was associated with greater postoperative BCVA at the 1-month follow-up (P = 0.007). A significant difference was found between different degrees of lens subluxation and the length of surgical time and complications. At follow-up, only two eyes (1.98%) were identified to have developed retinal detachments. In conclusion, better visual outcomes can be achieved when patients received an early operation with MCTR implantation.

Intraoperative vascular complications during 2278 cerebral endovascular procedures with multimodality IONM: relationship between signal change, complication, intervention and postoperative outcome.

BACKGROUND: Intraoperative neuromonitoring (IONM) is often used during cerebral endovascular procedures. OBJECTIVE: To investigate the relationship between intraoperative vascular complications and IONM signal changes, and the impact of interventions on signal resolution and postoperative outcomes. METHODS: A series of 2278 cerebral endovascular procedures conducted under general anesthesia and using electroencephalography and somatosensory evoked potential monitoring were retrospectively reviewed. A subset of 763 procedures also included motor evoked potentials (MEPs). IONM alerts were categorized as either a partial attenuation or complete loss of signal. Vascular complications were subcategorized as due to rupture, emboli, instrumentation, or vasospasm. Odds ratios (ORs) for new postoperative motor deficits were calculated and diagnostic accuracy was measured using sensitivity, specificity, and likelihood ratios. RESULTS: The overall incidence of new postoperative motor deficit was 1.2%; 20.4% in cases with an IONM alert and 0.09% in cases without an alert. Relative to procedures with no alerts, odds of a new deficit increased if there was partial signal attenuation (OR=210.9, 95% CI 44.3 to 1003.5, p<0.0001) and increased further with complete loss of signal (OR=1437.3, 95% CI 297.3 to 6948.2, p<0.0001). Relative to procedures with unresolved alerts, odds of a new deficit decreased if the alert was fully resolved (OR=0.039, 95% CI 0.005 to 0.306, p<0.002). Procedures using MEPs had slightly higher sensitivity (92.3% vs 85.7%) but slightly lower specificity (96.7% vs 98.2%). CONCLUSIONS: An IONM alert associated with an arterial complication is associated with a dramatic increase in odds of a new postoperative deficit; however, if there is resolution of the alert prior to closure, odds of a new deficit decrease significantly.

Intraoperative hypotension during liver transplant surgery is associated with postoperative acute kidney injury: a historical cohort study.

BACKGROUND: Acute kidney injury (AKI) occurs frequently after liver transplant surgery and is associated with significant morbidity and mortality. While the impact of intraoperative hypotension (IOH) on postoperative AKI has been well demonstrated in patients undergoing a wide variety of non-cardiac surgeries, it remains poorly studied in liver transplant surgery. We tested the hypothesis that IOH is associated with AKI following liver transplant surgery. METHODS: This historical cohort study included all patients who underwent liver transplant surgery between 2014 and 2019 except those with a preoperative creatinine > 1.5 mg/dl and/or who had combined transplantation surgery. IOH was defined as any mean arterial pressure (MAP) < 65 mmHg and was classified according to the percentage of case time during which the MAP was < 65 mmHg into three groups, based on the interquartile range of the study cohort: "short" (Quartile 1, < 8.6% of case time), "intermediate" (Quartiles 2-3, 8.6-39.5%) and "long" (Quartile 4, > 39.5%) duration. AKI stages were classified according to a "modified" "Kidney Disease: Improving Global Outcomes" (KDIGO) criteria. Logistic regression modelling was conducted to assess the association between IOH and postoperative AKI. The model was run both as a univariate and with multiple perioperative covariates to test for robustness to confounders. RESULTS: Of the 205 patients who met our inclusion criteria, 117 (57.1%) developed AKI. Fifty-two (25%), 102 (50%) and 51 (25%) patients had short, intermediate and long duration of IOH respectively. In multivariate analysis, IOH was independently associated with an increased risk of AKI (adjusted odds ratio [OR] 1.05; 95%CI 1.02-1.09; P < 0.001). Compared to "short duration" of IOH, "intermediate duration" was associated with a 10-fold increased risk of developing AKI (OR 9.7; 95%CI 4.1-22.7; P < 0.001). "Long duration" was associated with an even greater risk of AKI compared to "short duration" (OR 34.6; 95%CI 11.5-108.6; P < 0.001). CONCLUSIONS: Intraoperative hypotension is independently associated with the development of AKI after liver transplant surgery. The longer the MAP is < 65 mmHg, the higher the risk the patient will develop AKI in the immediate postoperative period, and the greater the likely severity. Anesthesiologists and surgeons must therefore make every effort to avoid IOH during surgery.