Lung preconditioning in anesthesia: Review of the literature

Lung injury can arise during or after anesthesia and can lead to a complicated postoperative course with great implications for the patient. Unfortunately, treatment of acute lung injury is at the moment mainly supportive and rates of recovery have not really improved in the recent years. In many cases, lung injury can be anticipated and preventive measures seem possible. This represents a unique challenge to the anesthesiologist, as some new opportunities to reduce the frequency and/or severity of lung injury seem now available. These chances may arise from the potency of preconditioning the lungs before the main injury, with smaller injurious insults. Although preconditioning began to be applicated first on the myocardium, experimental studies have shown potentially beneficial results also for the lungs. This review summarizes the main methods of lung preconditioning that have been tried in experimental studies in the literature and the main mechanisms that are perhaps involved. Emphasis is given in the two main methods of preconditioning that seem readily applicable in the clinical praxis, that is ischemic preconditioning, as well as preconditioning with volatile anesthetics. The few, but interesting clinical studies are also summarized and the future research points in this evolving field of anesthesia are stressed.

Predictive value of extravascular lung water indexed to predicted body weight

AIM: To investigate extravascular lung water indexed to predicted body weight (EVLWIp) and actual body weight (EVLWIa) on outcome of patients with severe sepsis.

METHODS: Transpulmonary thermodilution was prospectively used to measure cardiovascular hemodynamics, EVLWIp and EVLWIa via an arterial catheter placed in each patient within 48 h of meeting the criteria for severe sepsis from a medical intensive care unit (ICU) at a university affiliated hospital. Survival was the single dependent variable. In order to examine and compare the predictive power of EVLWIp, EVLWIa and other clinically significant factors in predicting the in-hospital survival status of severe sepsis patients in the medical ICU, a receiver operating characteristic (ROC) curve method to analyze the significant variables and the area under the ROC curve (AUC) of the variables, P value and 95%CI were calculated.

RESULTS: In total, 33 patients were studied. In the ROC curve method analyses, EVLWIp (the AUC: 0.849; P = 0.001, 95%CI: 0.72-0.98) was as predictive for in-hospital survival rate as variables with EVLWIa (AUC, 0.829; P = 0.001, 95%CI: 0.68-0.98). The proportion of patients surviving with a low EVLW (EVLWI < 10 mL/kg) was better than that of patients with a higher EVLW, whether indexed by actual (HR = 0.2; P = 0.0002, 95%CI: 0.06-0.42) or predicted body weight (HR = 0.13; P < 0.0001, 95%CI: 0.05-0.35) during their hospital stay with the Kaplan-Meier method (76% vs 12.5%, respectively).

CONCLUSION: This investigation proposed that EVLWIp is as good a predictor as EVLWIa to predict in-hospital survival rate among severe sepsis patients in the medical ICU.

Dexmedetomidine vs propofol in intensive care unit patients

Dexmedetomidine is indicated as a sedative agent in intensive care units (ICUs). While several clinical trials and two meta-analyses have compared this agent with propofol or midazolam, the results were variable depending on the specific end-point (e.g., duration of mechanical ventilation, ICU mortality, maintaining a target depth of sedation, incidence of delirium episodes, length of hospital stay). Hence, the effectiveness of this new agent vs the comparators seems to be controversial. Trial sequential analysis (TSA) is a statistical technique that can estimate the optimal, cumulative number of patients that would be needed to generate a conclusive result. We therefore applied a TSA model to the most recent meta-analysis evaluating dexmedetomidine. A total of 10 randomized controlled trials were included in our analysis. According to our results, the comparison of dexmedetomidine vs propofol showed no proof of incremental effectiveness for the end-points of length of ICUs stay and incidence of delirium episodes. In contrast, futility (i.e., proof of no incremental effectiveness) was demonstrated for the end-point of mechanical ventilation. Hence, the results for the comparison of dexmedetomidine vs propofol were inconclusive for the first two end-points; on the other hand, conclusiveness was reached for the third end-point. We conclude that the place of dexmedetomidine in therapy of critically ill patients is very uncertain and further controlled trials are still needed.

No pain, no social gains: A social-signaling perspective of human pain behaviors

In this review article, we describe a social-signaling perspective of human pain and pain empathizing behaviors which is based on the premise that pain percepts evolved to serve both intrapersonal as well as interpersonal, communicative functions. This perspective offers a generative framework for understanding the natural origin and proximate expression of felt pain and pain empathizing behaviors. The basic thesis is that humans evolved sensory-behavioral heuristics for perceiving and inhibiting exogenous and endogenous pain sensations as part of more general expressive styles characterized by the demonstration of vulnerability gestures (i.e., trustworthiness cues) versus empowerment gestures (i.e., capacity cues), and these styles ultimately facilitate broader self-protection and social novelty-seeking life-history behavior strategies, respectively. We review the extant literature on how social contextual factors (e.g., audience characteristics) and how structural and functional components of individual’s social network appear to influence the expression of pain behaviors in ways that support basic predictions from the social-signaling perspective. We also show how the perspective can be used to interpret conventional findings of sex differences in pain percepts and pain empathizing behaviors and for predicting how the situational context and individual’s peer networks modulate these differences in vitro and in vitro. We conclude the article by describing how pain researchers may better understand how varying levels and divergent directions of changes in affect tend to co-occur with systematic changes in internal vs external pain sensitivities, and thus why, from an evolutionary perspective, pain may occur in the presence and absence of physical tissue damage.

Practical diastology

Left ventricular (LV) diastolic dysfunction is being recognized as an important part in the pre-operative evaluation. Pre-operative LV diastolic dysfunction has been associated with increased risk of post-operative complications. Furthermore guidelines have been published on the assessment of LV diastolic function. However LV diastolic function is significantly influenced by loading conditions which are typically altered during cardiac and non-cardiac surgery. In addition, waveform analysis from the pulmonary artery catheter tend to correlate with diastolic function and loading conditions. The advantage of hemodynamic monitoring being that they are continuously displayed as opposed to intermittent diastolic parameters. Finally if the importance of diastolic function assessment is to estimate filling pressure, the presence of B lines with the use of lung ultrasound is a simpler method in detecting pulmonary edema. Another indirect evidence of either LV systolic or diastolic dysfunction is an abnormal near-infrared spectroscopy value. Finally it might be more important to evaluate right ventricular (RV) diastolic dysfunction as RV dysfunction is significantly associated with pulmonary hypertension and consequently mortality. Such assessment of RV diastolic dysfunction can be obtained continuously with the use of RV pressure waveform monitoring.

Anaesthesia and pancreatic surgery: Techniques, clinical practice and pain management

Pancreatic cancer continues to pose a major public health concern. The incidence of the disease is nearly equivalent to the death rate associated with the diagnosis of pancreatic cancer. Thus, there exists a need for continued improvement in the diagnostic, therapeutic and palliative care of these patients. There have been significant advances made over the years in the areas of critical care, anesthesia, and surgical technique, which have led to improved mortality rates and survival after resection for pancreatic cancer. Resections are performed with the goals of negative margins and minimal blood loss and referral to high-volume centers and surgeons is encouraged. However, 5-year survival rate after curative resection still remains at less than 20%. Perioperative management of pancreatic and periampullary cancer poses a considerable challenge to the pancreatic surgeon, anesthesiologist and the intensive care team. Major morbidity is often secondary to pancreatic anastomotic leakage and fistula or infection. The anesthesiologist plays a crucial role in the perioperative management of such patients and in the pain control. Pancreatic ductal adenocarcinoma has a high rate of neural invasion (80%-100%) and can be associated with moderate to severe pain. In the recent past, new information has emerged on many issues including preoperative biliary drainage, nutritional support, cardiovascular assessment, perioperative fluid therapy and hemodynamic optimization. Careful patient selection and appropriate preoperative evaluation can greatly contribute to a favorable outcome after major pancreatic resections.

Regional anesthesia for acute pain management in elderly patients

Normal aging is a process that involves loss of functional reserve of most organ systems of the human body, most significantly: cardiovascular, pulmonary, renal and nervous systems. Advancements in both surgery and anesthesia have made it possible to operate more safely on the elderly population and those older patients with multiple severe co-morbidities that were not routinely possible in the recent past. Regional anesthesiologist have proven to be instrumental in this regard as regional anesthetic/analgesic techniques may now permit surgeons to operate on the elderly who were not ideal surgical candidates or unable to tolerate general anesthesia. In addition, regional techniques provide alternatives that may optimize acute pain control and reduce the incidence of devastating side effects during the perioperative period such as: myocardial infarction, pulmonary embolism, pneumonia, and also increases the opportunity to allow for early ambulation and shorter hospital stays. These anesthetic options now provide the elderly patient with better medical care alternatives, but also can show a significant financial impact on health care system resources. Further understanding on aging molecular biology, physiology and pathophysiology, together with technical improvements of regional anesthetic techniques will continue to make it safer and more efficacious to operate on the elderly population with evidence of reduced morbidity and mortality. Although there is only anecdotal evidence that regional anesthesia (RA) improves survival, there is little doubt that RA plays an important role in perioperative optimization of pain control and decreases pain management complications as well as a reduction in healthcare costs. Beyond traditional operating rooms, elderly patients may increasingly benefit from RA and acute pain management in Emergency Rooms, medical clinics and even within a patient’s home. Therefore, the focus of this review is directed toward geriatric patients and beneficial effects of RA on outcomes in the elderly.

Review of essential understanding of ultrasound physics and equipment operation

Ultrasound (US) is being extensively used an imaging tool in regional anesthesia (RA) and pain practice. Although it was first used in a regional block in 1978, it was only in 1994 that the first direct use of US in RA was reported. Like any other medical tool, its utility is only realized when the performing physician is able to understand the principles behind its application. Efficient use of US also requires an understanding of physical variables which can be suitable modified to produce a clear image of the structure of importance. This brief narrative review summarises the advantages of US in RA and pain practice over the conventionally used localising or imaging tools. The second section deals with the physics behind US. It highlights the necessary physical concepts such as wavelength, frequency and generation of US waves. It also informs the reader about the possible US and tissue interactions, use of US transducers and their differences. The third section deals with understanding the control variables in a typical US machine and how they could be modified to improve the image quality. The final section highlights the various artifacts that could be associated.

Fractured tracheostomy tube obturator: A rare cause of respiratory distress in a tracheostomized patient

Foreign body aspiration is a worldwide health problem which often results in life threatening complications. Tracheostomy tube fracture resulting in airway obstruction is a serious condition which has been reported in the medical literature. We report a rare case of a tracheostomy obturator fractured and lodged in tracheobronchial tree in a patient who presented with acute respiratory distress. Rigid or flexible bronchoscopy is frequently necessary for the diagnosis as well as the treatment. In adults, removal of the foreign body can be attempted during a diagnostic examination with a fiberoptic bronchoscope under lignocaine local infiltration with sedation, which may help to avoid any further invasive procedures. Flexible bronchoscopy should always be considered in foreign body aspiration. A periodic review of the techniques of tracheostomy care, including timely check-ups for signs of wear and tear, can possibly eliminate such avoidable late complications.

Comparison between intrathecal hyperbaric bupivacaine and levobupivacaine for ambulatory knee arthroscopy

AIM: To compare the effect of hyperbaric levobupivacaine and bupivacaine on the quality of the block, patient satisfaction, and discharge time in patients undergoing arthroscopic knee surgery under unilateral spinal anesthesia.

METHODS: One hundred and thirty-two patients, American Society of Anaesthesiologists I or II, scheduled for elective ambulatory knee arthroscopy were randomly assigned to four double-blind groups. To achieve a unilateral spinal block, Group BF received 5 mg of hyperbaric bupivacaine plus 20 μg of fentanyl intrathecally, Group LF received 5 mg of hyperbaric levobupivacaine plus 20 μg of fentanyl intrathecally, Group B received 5 mg of hyperbaric bupivacaine intrathecally, and Group L received 5 mg of hyperbaric levobupivacaine intrathecally. The level and duration of the sensory block, the intensity and duration of the motor block, the time to first analgesic requirement, and the time elapsed until the patient’s discharge were recorded. Hemodynamic values and adverse effects were also recorded.

RESULTS: The duration of time needed to reach the T12 dermatome level was significantly longer in Group L [7 (3-20) min] than in Group B [6 (3-12) min] (P = 0.006). The maximum sensory level reached on the side undergoing the operation was significantly higher in Group BF than in Group B (P < 0.05). The intensity of the motor blockade was greater in Group BF than in Group LF and L. Complete recovery from motor blockade occurred earlier in Groups LF [75 (45-165) min] and L [63 (35-120) min] than in Group BF [115 (60-180) min] (P < 0.05). The length of time needed for the sensory block to regress to the level of S2 was shorter in Group L (154 ± 50) than in Group BF (192 ± 66) (P < 0.05). The quality of the block was significantly lower in Group L than in Groups BF, LF and B (P = 0.012, P = 0.003, and P < 0.001, respectively). The time elapsed until Visual Analog Scale ≥ 4 was significantly shorter in Group L (110 ± 48) than in Groups BF (200 ± 60), LF (156 ± 61) and B (162 ± 52) (P < 0.05). The time elapsed until the patient’s discharge was shorter in Groups B (244 ± 54) and L (229 ± 55) than in Group BF (288 ± 64) (P = 0.021 and P = 0.001, respectively). There were no differences among the groups regarding hemodynamic parameters and adverse events, except for pruritus. The occurrence of pruritus was significantly more frequent in Groups BF and LF than in other groups.

CONCLUSION: In conclusion, 5 mg of hyperbaric bupivacaine and 5 mg of hyperbaric levobupivacaine plus 20 μg of fentanyl provided a better spinal anesthesia than 5 mg of hyperbaric levobupivacaine alone.

Suspected cerebral arterial gas embolism during a laparoscopic Nissen fundoplication

We present the first case report known to us of a suspected cerebral arterial gas embolism (CAGE) leading to transient left-sided hemiparesis after a laparoscopic Nissen fundoplication. During the operation there was no evidence of hemodynamic compromise and the end-tidal carbon dioxide level and oxygen saturation had been within normal limits. Radiological studies and transesophageal echocardiography showed no abnormalities. We conclude that CAGE can occur during uncomplicated laparoscopic surgery even in the absence of demonstrable intracardiac shunts.

Electrochemotherapy and heart function: Treatment in a patient with implantable cardioverter defibrillator/pace-maker

Electrochemotherapy (ECT) is a recently described therapy that relies on the permeation of cancer cell membranes by electrical pulses to enhance cytotoxic drug penetration. It has been successfully used in the treatment of primary and metastatic skin cancer. Systemic chemotherapy is the most commonly used therapeutic strategy, and the prevailing orientation calls for the administration of the maximum tolerated dose; however, considerable limitations exist including toxicities to healthy tissues and low achievable drug concentrations at tumor sites. We reported a case of an 83-years-old patient with a laterocervical metastasis of a squamous epidermoidal lip cancer. The patient had a complex medical history and an implantable cardioverter defibrillator (ICD)/pace-maker. The lesion was localized in the supraclavicular right side with a distance from the pace-maker/ICD about 5 cm, but the nodule was not deeply located. The ECT was performed under general anesthesia and particular attention we put on the interference with the functioning of the heart. The synchronization algorithm currently implemented in Clinoporator Vitae device coupled with the external triggering device AccuSync proved to be effective in preventing external stimulation of the heart during the so-called vulnerable period of the ventricles. As a result all electroporation pulses in our study were delivered outside the vulnerable period and no heart arrhythmias or any other pathological morphological changes were observed. The safety of treatment was demonstrated also by absence of side effects during and after ECT.

Management of a patient with perioperative saddle embolus

Pulmonary embolism is a major cause of morbidity and mortality. Risk factors include venous stasis, endothelial injury, and hypercoagulability. Prevention centers on the use of sequential compression devices and anticoagulation in the hospital patient. This is the case of a 45-year-old male who presented for open reduction and internal fixation of tibia plateau fracture. He developed a saddle embolus during the perioperative period which was diagnosed in the recovery room after workup for the cause of his poor oxygenation. A chest computed tomographic scan showed an extensive saddle embolus with partial occlusion of the bilateral main pulmonary arteries and all segmental pulmonary artery branches. This case report discusses his diagnosis, management and clinical course. In addition, risk factors, treatment and prevention for pulmonary embolus and described.

Clinical pharmacology of intravenous paracetamol in perinatal medicine

Clinical pharmacology aims to predict drug-related effects based on compound and population specific pharmacokinetics (PK, concentration-time), and pharmacodynamics (PD, concentration-effect). Consequently, dosing needs to be based on the physiological characteristics of the individual patient. Pregnancy and early infancy hereby warrant focused assessment. The specific characteristics of both subpopulations will be illustrated based on observations on intravenous (iv) paracetamol PK and PD collected in these specific populations. At delivery, there is a significant higher paracetamol clearance (+ 45%, L/h) when compared to non-pregnant observations. This higher clearance is in part explained by a proportional increase in oxidative metabolite production, but mainly an increase in glucuronidation. When focusing on PD, an association between maternal paracetamol exposure and atopy in infancy and fetal gastroshizis has been reported. In early infancy, paracetamol clearance is significantly lower and mainly depends on size (weight 0.75), while also the distribution volume is higher (L/kg). Reports on hepatic tolerance, haemodynamic stability and impact of body temperature have been published while the concentration effect profile for analgesia seems to be similar between neonates and children. Similar to maternal exposure, there are reports on the association with atopy. Studies on the use of paracetamol to close the patent ductus arteriosus are ongoing. At least, these observations provide evidence on the need to study commonly administered anesthetics in such specific subpopulations with specific focus on both population specific PK and PD to further improve patient tailored pharmacotherapy.

Anesthetic management of patient with hypertrophic cardiomyopathy and automatic implantable cardioverter defibrillator with a hand fracture

A 26-year-old male with a history of hypertrophic cardiomyopathy (HCM) and ventricular arrhythmias s/p automatic implantable cardioverter defibrillator (AICD) placement presented for open reduction and internal fixation of an open third metacarpal fracture and extensor tendon repair. He underwent successful surgery after placement of an ultrasound-guided infraclavicular brachial plexus block with ropivacaine 0.5% as the main anesthetic. This case report discusses the anesthetic management of patients with HCM and AICD, different approaches available for brachial plexus blockade, and potential complications of anesthesia and surgery in this group of patients.

What is the purpose of launching World Journal of Anesthesiology?

The launch of World Journal of Anesthesiology (WJA) is great news for the community of anesthesiology. Anesthesiology is a rapidly evolving medical specialty. The practice of anesthesia is broad and has an important impact on our society. Thus, it is necessary to have a multi-modal system to rapidly disseminate anesthesiology-related knowledge. WJA’s preparatory work was initiated on December 3, 2010, will be published on December 27, 2011. The WJA Editorial Board has now been established and consists of 121 distinguished experts from 28 countries. It will publish various formats of papers including original studies, review, commentary, guidelines, case report, book review and letters to the editor. The publication of the accepted papers will be quick and it is free of charge for readers to download and read any articles in the journal. Thus, WJA should be an excellent choice for anyone to consider publishing anesthesiology-related papers. Congratulations to the birth of WJA, a new member of World series journal family.