Evaluation of colour vision impairment during acute hypobaric hypoxia in aviation medicine: a randomized controlled trial.

The digitization of aircraft cockpits places high demands on the colour vision of pilots. The present study investigates colour vision changes upon acute exposure to hypobaric hypoxia. The digital Waggoner Computerized Color Vision Test and the Waggoner D-15 were performed by 54 healthy volunteers in a decompression chamber. Respective altitude levels were sea level, 10,000 or 15,000 ft for exposure periods of 15 and 60 min, respectively. As for 60 min of exposure a significant decrease in colour perception was found between subjects at 15,000 ft as compared to the control group as well as between subjects at 15,000 ft as compared to subjects at 10,000 ft. No significant difference was found in the comparison within the 15,000 ft groups across time points pre-, peri-, and post-exposure. Thus, pilots appear to experience only minor colour vision impairment up to an exposure altitude of 15,000 ft over 60 min of exposure.

[Effect of implementation of a trauma leader on process parameters for polytrauma treatment in the shock room of a tertiary care hospital]. / Auswirkung der Implementierung eines Schockraumkoordinators auf Prozessparameter der Polytraumaversorgung im Schockraum eines Maximalversorgers.

BACKGROUND: In patients up to the age of 40 years old severe trauma is the most frequent cause of death in Germany. According to the current S3 guidelines on treatment of polytrauma and the severely injured, since 2011 the presence of a shock room coordinator should be considered, who can improve the survival of patients by optimized treatment quality and times. The aim of the present study was to analyze various parameters of shock room treatment for polytraumatized patients before and after implementation of a shock room coordinator for treatment of polytrauma. MATERIAL AND METHODS: To ensure an adequate period of time between the implementation of the shock room coordinator in 2011, data from 2009 and 2012 were included for comparative purposes. All scanned protocols of shock room treatment in the period from 1 January 2009 to 31 December 2009 and from 1 January 2012 to 31 December 2012 were inspected and evaluated. RESULTS: In total 213 shock room treatments from 2009 and 420 from 2012 were included. The mean number of shock room treatments in 2009 was 17.8 per month and in 2012 the mean number was 35 per month. The mean number of shock room treatments was nearly doubled in comparison (p < 0.001). The mean time for shock room treatment in 2009 was 74.8 min and in 2012 the mean time was 69 min and was therefore reduced by 5.8 min (p = 0.56). CONCLUSION: The treatment of polytraumatized patients in the presence of a shock room coordinator and after implementation of the standard operating procedure (SOP) was neither statistically nor clinically relevantly shortened.

[Deployment of the in-hospital emergency team in a tertiary care university hospital : Data analysis for the time period 2013-2016 in North-Rhine/Westphalia]. / Einsätze des innerklinischen Notfallteams eines überregionalen Maximalversorgers : Datenanalyse für den Zeitraum 2013­2016 im nordrhein-westfälischen Raum.

BACKGROUND: Recent studies demonstrated that in-hospital emergencies are linked to a higher patient mortality. In approximately 10% of patients an unexpected incident occurs during the hospital stay. Therefore, the establishment of in-hospital medical emergency teams (MET) is becoming more important in the interdisciplinary emergency treatment. The aim of this study was an analysis of medical documentation, operational tactics and procedures taken by MET of the University Hospital of Cologne in a 4-year period ranging from 2013 to 2016. MATERIAL AND METHODS: A retrospective analysis of 1664 emergency forms from MET activities at the University Hospital of Cologne from 1 January 2013 to 31 December 2016 was carried out. Every MET activation call via the emergency telephone number (5555) and subsequent emergency treatment was recorded using a standardized documentation form. The registry number on ClinicalTrials.gov is NCT03786445. RESULTS: There were 1664 emergency team calls in the whole study period. Between 2013 (404 calls) and 2016 (461 calls) the number of calls increased by 11.4%. The total mission time of the MET increased in the study period from 8342 min (2013) to 10,800 min (2016, +29.5%) and the average mission time increased from 2013 (35 min) to 2016 (40 min) by 14.3%. The primary reason for activation was collapse or syncope and was the underlying cause for 29% of calls. The number of deployments for emergencies at weekends was 50% of those during weekdays and 6.5% of the calls were for cardiopulmonary resuscitation (CPR). CONCLUSION: Analysis of data revealed that the number of MET calls, total operating time and average deployment time increased from 2013 to 2016. The primary reason for MET activations was collapse or syncope and every 17th deployment was for cardiopulmonary resuscitation. The incidence of in-hospital cardiac arrests decreased during the study period.

[Anesthesia in patients with NBIA : Neurodegeneration with brain iron accumulation]. / Anästhesie bei Patienten mit NBIA : Neurodegeneration mit Eisenablagerung im Gehirn.

BACKGROUND: Neurodegeneration with brain iron accumulation (NBIA) forms a group of rare hereditary diseases with rapid neurodegenerative progression due to an abnormal accumulation of iron in the basal ganglia. This causes extrapyramidal symptoms as well as dystonia and mental retardation. The most common form of NBIA is pantothenate kinase-associated neurodegeneration (PKAN, formerly Hallervorden-Spatz syndrome). There are multiple anesthesiological challenges with great implications for the clinical routine, particularly regarding the preparation for general anesthesia and the premedication visits. As with other orphan diseases, the available recommendations are mainly based on case reports. OBJECTIVE AND METHODS: This article gives a short overview of complications associated with NBIA pertaining to general anesthesia. This includes anesthesia-relevant clinical symptoms and perioperative management. The published literature and case reports (available on PubMed) were reviewed to extract a set of recommendations. RESULTS: So far only a few reports have included the anesthesia management of NBIA patients. Most of them refer to PKAN as the predominant type (50% of cases). Recommendations were found on www.orphananesthesia.eu and consensus guidelines on PKAN in general. In particular, dystonia-related restrictions in the maxillofacial area can complicate airway management and cause difficulties with respect to intubation. Furthermore, local or regional anesthesia as the sole anesthesia technique is not eligible/viable due to the reduced compliance of the patient. Special attention should be paid to a timely premedication visit and evaluation to ensure sufficient time to safely plan and prepare the anesthetic procedure. CONCLUSION: The handling of NBIA patients requires good preparation, including an interdisciplinary team and customized time management. In principle, both general anesthesia as a balanced method and total intravenous anesthesia (TIVA) seem to be possible/viable options. The main focus is on airway management. Even after brief sedation in the context of diagnostic measures, the patient should be monitored for longer than usual.

[Transport of ventilated emergency patients from the air rescue service to the hospital destination (HOVER study) : Results of an online survey]. / Transport beatmeter Notfallpatienten vom Hubschrauber zum Krankenhauszielort (HOVER-Studie) : Ergebnisse einer Onlineumfrage.

BACKGROUND: In Germany more than 110,000 helicopter emergency medical service (HEMS) missions are carried out annually. A considerable number of patients are ventilated during the flight. So far, structured surveys with respect to the ground transport from the helipad to the hospital facility and handover of ventilated patients in the emergency room (ER) are not available in the German-speaking HEMS system. The handover of ventilated HEMS patients in the ER (HOVER I study) explored the use of the helicopter ventilator and medical equipment during the transport from the hospital landing site to the ER. METHOD: After approval by the HEMS operators, emergency medical doctors and HEMS technical crew members (HEMS-TC) of 145 German-speaking HEMS bases were invited to participate in an anonymous online survey (period: 1 February 2018-1 March 2018). Each participant was only allowed to submit the survey once. RESULTS: Data of 569 participants were completely analyzed, with responses from 429 emergency physicians and 140 HEMS-TC (75% from Germany, 13% Switzerland, 11% Austria, 1% Italy and Luxembourg). The most frequent type of aircraft used was the Eurocopter (EC)/Airbus helicopter (H) 135 (60.5%) followed by the EC/H 145 (33%). The majority of the respondents (53%) principally used the helicopter ventilator machine for patient transport from the helipad to the ER, 38% used it depending on the circumstances and 7% never used it. Of the participants 52% always took the emergency backpack for patient transport to the ER, 43% depending on the situation and 5% never took it along. The availability of oxygen or a ventilator at the helipad was considered to be helpful (59% and 45%, respectively), obligatory (25% and 14%, respectively) but was also considered unnecessary by some participants (16% and 40%, respectively). The collection of the HEMS team by a hospital team at the helipad was rated as helpful (64%) or mandatory (19%), 12% considered it to be unimportant and 5% even disturbing. For most respondents (58.5%) the responsibility for the patient ended after a structured handover on reaching the internal hospital target area (e.g. the ER). CONCLUSION: The management of the handover of ventilated emergency patients in German-speaking HEMS is heterogeneously structured. Only approximately 50% of the participants frequently carried the helicopter ventilator and emergency equipment during patient transport to the ER. Depending on the situation, more than 90% of the respondents used the helicopter ventilator and emergency backpack during the transport. The collection of the HEMS team by a hospital team at the helipad was appreciated by the majority of participants. The use of the helicopter ventilator for patient transport to the ER needs to be explored in future studies. The study was registered at the Research Registry ( www.researchregistry.com ) under the following number: researchregistry2925.

The choice of the hypnotic drug (volatile or propofol) for maintenance of anesthesia does not influence surgical conditions during cranioplasty.

BACKGROUND AND AIMS: In contrast to propofol, volatile agents are often considered harmful to maintain anesthesia due to increasing brain volume and potential deleterious effects. Patients for cranioplasty, including patients with large bone defects, could be susceptible for intraoperative complications but have not properly been investigated so far. The aim of the present study was to evaluate brain swelling, intraoperative conditions, surgical course, and postoperative complication rates of propofol-based vs. volatile-based anesthesia. MATERIAL AND METHODS: In this monocentric, retrospective, and observational study, we collected demographic, clinical, and outcome data of patients undergoing cranioplasty between December 2010 and September 2014. According to the hypnotic drug used, patients were assigned to either a propofol or a volatile group. The primary outcome parameter was brain swelling. For comparison of the groups, univariate analysis was performed using Chi-square and Mann-Whitney-U test. RESULTS: One hundred and one patients were identified in the period. Twenty-three patients were excluded due to cerebrospinal fluid diversion. Baseline characteristics and preoperative conditions did not vary between the groups except a higher body mass index and positive end-expiratory pressure (PEEP) in the propofol group. The choice of anesthesia (volatile or intravenous) influence neither the intraoperative local conditions nor postoperative complication rate. No significant risk factor for impaired bone flap placement was identified. CONCLUSIONS: In a well-defined cohort, the choice of the anesthetic agent does not influence the degree of intraoperative brain swelling, bone flap fit, and postoperative course.

[Rapid sequence induction and intubation in patients with risk of aspiration : Recommendations for action for practical management of anesthesia]. / "Rapid sequence induction and intubation" beim aspirationsgefährdeten Patienten : Handlungsempfehlungen für das praktische anästhesiologische Management.

BACKGROUND: Induction of general anesthesia in patients with risk for aspiration needs special considerations to avoid the incidence and severity of complications. Since no evidence-based guidelines support the challenge for anesthesiologists various practical recommendations exist in clinical practice for rapid sequence induction and intubation (RSI). The aim of this systematic review is, to summarize the evidence and recommend a decision making process. MATERIAL AND METHODS: Multilevel RAND-delphi-method (RAND: Research and Development) combined with systematic literature research, individual assessment and evaluation, consensus conferences and final common sequence. RESULTS AND DISCUSSION: The consideration of all practical, clinical procedures in patients at risk for aspiration represents an effective prevention of pulmonary aspiration during the induction of anesthesia. These include the optimal drug pre-treatment with antacids (e. g. sodium citrate) for highly aspiration-endangered and proton pump inhibitors or H2 blockers in other patients the evening before. Each patient should be examined and explained prior to RSI according to the recommendations of the National German Society of Anesthesiology for preoperative evaluation. A RSI should be performed in patients with no 2h liquid and no 6h food fasting or acute vomiting, sub-ileus or ileus, or no protective reflexes or a gastrointestinal passenger disorder. In addition, RSI should be performed in pregnant women after the 3rd trimester and during birth. The expertise and competence of the physician before and during rapid sequence induction and intubation about the respective task distribution minimizes the risk of aspiration, as does the adequate equipment, as well as an optimized upper body elevation of the patient. Consistent pre-oxygenation with an FIO2 of 1.0 (FetO2-concentration > 0.9) and an oxygen flow > 10 l/min using a completely sealing respiratory mask with capnography should take 3-5 minutes. Fast enough deep anesthesia and muscle relaxation to avoid coughing and choking can be achieved by a combination of opioid, hypnotic and muscle relaxation. In addition, an opioid of choice, propofol, thiopental, etomidate and ketamine can be used as hypnotic and rocuronium with the availability of sugammadex should be used as muscle relaxant. If there are no contraindications, succinylcholine can also be used as a muscle relaxant. In case of an unexpected difficult airway, a 2nd generation extraglottic airway device should be used. During regurgitation or aspiration, intensive medical monitoring and fiber-optic bronchoscopy should be performed, depending on the degree of severity and an X­ray thorax image or a CT scan should be performed if symptoms arise. Three factors reduce the risk of aspiration: expertise, support from an experienced anesthesiologist and close monitoring of an inexperienced anesthesiologist.

[Performance of prehospital emergency anesthesia and airway management : An online survey]. / Durchführung einer prähospitalen Notfallnarkose und Atemwegssicherung : Eine Onlineumfrage.

BACKGROUND: The goal of rapid sequence induction (RSI) in cases of emergency situations is to secure the airway as quickly as possible to prevent pulmonary aspiration of gastric contents; however, the technique itself is not standardized. For example, the choice of drugs, application of cricoid pressure and the patient position remain controversial. A survey of emergency medical services (EMS) physicians throughout Germany was carried out to assess the different RSI techniques used and with respect to complying with the national guidelines for emergency airway management anesthesia and local standard operating procedures (SOP). MATERIAL AND METHODS: Between 1 April 2017 and 31 May 2017, EMS medical directors in Germany were contacted and asked to distribute a 28-question online questionnaire to local EMS physicians. Of the questions 26 were multiple choice and 2 with plain text. After 6 weeks an e­mail reminder was sent. In addition, the survey was distributed via social media to EMS physicians. RESULTS: In total the survey was opened 2314 times and 1074 completed responses were received (completion rate 46%). Most of the participants were male (78%) and anesthesiologists (70%) and only one quarter had a local SOP for RSI. The most frequently used muscle relaxant was succinylcholine (62%) and over half of the participants reported using cricoid pressure (57%). There was a distinction between the specialist disciplines in the selection of drugs. Propofol was used most by anesthesiologists, while the others still used etomidate on a larger scale. Nearly 100% could fall back on supraglottic devices (one third laryngeal mask, two thirds laryngeal tube) but only 32.8% with the recommended esophageal drainage. A video laryngoscope was available to 51% of all EMS physicians surveyed. CONCLUSION: The results of the survey demonstrate heterogeneity in RSI techniques used by EMS physicians in Germany. Medical equipment and safe care practices, such as labeling of syringes varied considerably between different service areas. The recommendations of the S1 national guidelines on emergency airway management and anesthesia should be adhered to together with the implementation of local SOPs.

Pre-operative evaluation of adults undergoing elective noncardiac surgery: Updated guideline from the European Society of Anaesthesiology

The purpose of this update of the European Society of Anaesthesiology (ESA) guidelines on the pre-operative evaluation of the adult undergoing noncardiac surgery is to present recommendations based on the available relevant clinical evidence. Well performed randomised studies on the topic are limited and therefore many recommendations rely to a large extent on expert opinion and may need to be adapted specifically to the healthcare systems of individual countries. This article aims to provide an overview of current knowledge on the subject with an assessment of the quality of the evidence in order to allow anaesthesiologists all over Europe to integrate - wherever possible - this knowledge into daily patient care. The Guidelines Committee of the ESA formed a task force comprising members of the previous task force, members of ESA scientific subcommittees and an open call for volunteers was made to all individual active members of the ESA and national societies. Electronic databases were searched from July 2010 (end of the literature search of the previous ESA guidelines on pre-operative evaluation) to May 2016 without language restrictions. A total of 34 066 abtracts were screened from which 2536 were included for further analysis. Relevant systematic reviews with meta-analyses, randomised controlled trials, cohort studies, case-control studies and cross-sectional surveys were selected. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to assess the level of evidence and to grade recommendations. The final draft guideline was posted on the ESA website for 4 weeks and the link was sent to all ESA members, individual or national (thus including most European national anaesthesia societies). Comments were collated and the guidelines amended as appropriate. When the final draft was complete, the Guidelines Committee and ESA Board ratified the guidelines.(AU)

[Correct positioning of central venous catheters in pediatrics : Are current formulae really useful?] / Sichere Platzierung von zentralen Venenkathetern im Kindesalter : Sind aktuelle Formeln wirklich sinnvoll?

BACKGROUND: Correct positioning of a central venous catheter (CVC) tip in pediatric patients is very important. Malpositioning may lead to direct complications, such as arrhythmia and increase the risk of thrombosis, infections, valve failures or pericardial tamponade. OBJECTIVE: The aim of this review was to identify and summarize published formulae for the correct positioning of the CVC tip in children and to discuss the benefits of these formulae for the daily routine. MATERIAL AND METHODS: A systematic and standardized search in Medline and PubMed was performed to identify published formulae. Formulae for insertion depth of the CVC tip over the right internal jugular vein are discussed. The keywords "pediatric" or "pediatric", "children", "central venous catheter", "CVC", "central venous", "length", "insertion", "optimal", "formula", "depth", "correct position" and "right position", "internal jugular vein" were used to identify the formulae. RESULTS: A total of 854 publications were found and 127 publications were analyzed. The publications were subsequently assessed and classified independently by a specialist in anesthesiology and a specialist in pediatrics. A total of six publications described different body height-based formulae for calculation of a CVC insertion depth. No prospective evaluation of these formulae was performed to show if it is possible to place a CVC tip at the optimal position. CONCLUSION: The benefit of a formula for daily practice is very limited due to the problem of choosing the right insertion point. The recommended insertion depth should be considered as an indicator and a verification of the CVC tip position should be done using an imaging technique.

[Which patients benefit from transport with ongoing cardiopulmonary resuscitation? : Retrospective analysis of 70 patients with refractory preclinical cardiac arrest]. / Welcher Patient profitiert von einem Transport unter laufender kardiopulmonaler Reanimation? : Retrospektive Analyse von 70 Patienten mit refraktärem präklinischem Herzstillstand.

BACKGROUND: Mortality in patients with out-of-hospital cardiac arrest (OHCA) remains very high despite advances in resuscitation algorithms. Most of these patients die at the scene and do not reach hospital. It is currently the subject of discussion whether transport to hospital with ongoing cardiopulmonary resuscitation (CPR) improves survival and neurological outcome in patients with OHCA. OBJECTIVE: The aim of this study was to identify predictors of survival and good neurological outcome in patients after OHCA who were transported to hospital with ongoing CPR. PATIENTS AND METHODS: A total of 70 consecutive patients with refractory OHCA (mean age 54.7 ± 15 years) transported to hospital with ongoing CPR were retrospectively analyzed. Neurological outcome was assessed after 30 days based on the Glasgow-Pittsburgh cerebral performance category (CPC). RESULTS: After 30 days 82.9% of the patients enrolled in the trial died (CPC score of 5), 8 patients (11.4%) showed a good neurological recovery with CPC scores of 1-2 and 4 patients (5.7%) had a poor neurological outcome with CPC scores of 3-4. Predictors of good neurological outcome were witnessed arrest, initial defibrillatable rhythm and serum lactate levels on admission. In all patients with good outcome, the index event for OHCA was from cardiac causes. CONCLUSION: Selected patient collectives can benefit from transport to hospital with ongoing cardiopulmonary resuscitation (CPR).

The effect of neuromuscular blockade on the efficiency of facemask ventilation in patients difficult to facemask ventilate: a prospective trial.

Facemask ventilation of the lungs can be an important rescue intervention in a 'cannot intubate' scenario. We assessed the effect of neuromuscular blockade on expiratory tidal volumes in patients with expected difficulty in mask ventilation. The lungs of patients with at least three predictors of difficulty in mask ventilation were ventilated using a facemask held with two hands, with mechanical ventilation set in a pressure-controlled mode. Tidal volumes were recorded before and after the establishment of complete neuromuscular block. In 113 patients, median (IQR [range]) tidal volume increased from 350 (260-492 [80-850]) ml initially, by 48% to 517 (373-667 [100-1250]) ml 30 s after rocuronium administration, (p < 0.001). After the onset of the complete neuromuscular block, a median tidal volume of 600 (433-750 [250-1303]) ml was observed, corresponding to an increase of 71% from baseline values (p < 0.001), and 16% from values obtained 30 s after rocuronium administration, respectively; p = 0.003). No decrease in the tidal volume during the measurements was observed. We conclude that the administration of rocuronium at a dose of 0.6 mg.kg-1 was able to improve facemask ventilation in all cases with a potentially clinically relevant increase in tidal volume. The early use of a neuromuscular blocking agent can be considered as a therapeutic option in case of difficulty with mask ventilation.

[Anaesthesia procedures and invasive vascular access in severely injured patients at trauma room admission in Germany : An online survey]. / Anästhesiologisches Vorgehen und invasive Gefäßzugänge bei der klinischen Erstversorgung von schwer verletzten Patienten in Deutschland : Onlineumfrage.

BACKGROUND: The continuous monitoring of vital parameters and subsequent therapy belong to the core duties of anaesthetists during acute trauma resuscitation in the trauma room. Important procedures may include placement of arterial lines and central venous catheters (CVCs). Knowledge of indication, performance and localization of invasive catheterisation of trauma care in Germany is scarce. METHODS: After approval of the German Society of Anaesthesiology and Intensive Care Medicine we conducted an online survey about arterial and central venous catheterisation of severely injured patients with consideration of common practice used by anaesthetists in German trauma rooms. Data are presented in a descriptive manner. RESULTS: Of 843 hospitals invited for the survey, 72 (8.5%) had complete and valid data and were thus included in the analysis. Of these, 47% were supra-regional (level 1) trauma centres, 38% regional trauma centres and 15% local trauma centres. The annual mean injury severity score (ISS) of admitted patients to these hospitals was 21 ± 10. In the trauma room, the responding hospitals place CVCs (49%) and arterial lines (59%) only in haemodynamically unstable patients, whereas 24% (CVC) and 39% (arterial line) do when pathological laboratory tests were confirmed. Standard operating procedures (SOPs) merely exist for placement of either arterial lines (25%) or CVCs (22%) in multiple trauma resuscitation. The decision to perform CVC or arterial line placement is usually (79%) at the discretion of the attending anaesthetist. The preferred anatomical access site for CVCs is the right internal jugular vein (46%) and for arterial lines the radial artery (without side preference) (57%), respectively. Of the responding hospitals, 49% prefer landmark-guided CVC-puncture (91% of arterial lines) instead of 43% using sonographic guidance (9% of arterial lines). Intravascular electrocardiography monitoring for CVC tip detection is used by 36%. CONCLUSION: In Germany, medical indication and schedule of invasive vascular catheterisation of severely injured patients in the trauma room is rarely regulated by SOPs and often performed at the discretion of the attending trauma team. Sonographic assistance during vascular puncture and electrocardiography for CVC tip detection is not as common as in non-emergency anaesthesia. Further studies are required to explore the real necessity and safety of invasive vascular catheterisation in multiple trauma patients in order to improve trauma care.

[Chest decompression in emergency medicine and intensive care]. / Die Thoraxdekompression in der Notfall- und Intensivmedizin.

Decompression of the chest is a life-saving invasive procedure for tension pneumothorax, trauma-associated cardiopulmonary resuscitation or massive haematopneumothorax that every emergency physician or intensivist must master. Particularly in the preclinical setting, indication must be restricted to urgent cases, but in these cases chest decompression must be executed without delay, even in subpar circumstances. The methods available are needle decompression or thoracentesis via mini-thoracotomy with or without insertion of a chest tube in the midclavicular line of the 2nd/3rd intercostal space (Monaldi-position) or in the anterior to mid-axillary line of the 4th/5th intercostal space (Bülau-position). Needle decompression is quick and does not require much material, but should be regarded as a temporary measure. Due to insufficient length of the usual 14-gauge intravenous catheters, the pleural cavity cannot be reached in a considerable percentage of patients. In the case of mini-thoracotomy, one must be cautious not to penetrate the chest inferior of the mammillary level, to employ blunt dissection techniques, to clearly identify the pleural space with a finger and not to use a trocar. In extremely urgent cases opening the pleural membrane by thoracostomy without inserting a chest tube is sufficient in mechanically ventilated patients. Complications are common and mainly include ectopic positions, which can jeopardise effectiveness of the procedure, sometimes fatal injuries to adjacent intrathoracic or - in case of too inferior placement - intraabdominal organs as well as haemorrhage or infections. By respecting the basic rules for safe chest decompression many of these complications should be avoidable.