Ventilator-associated complications, including infection-related complications: the way forward

Pain management during a bromelain-based selective enzymatic debridement in paediatric and adult burn patients

BACKGROUND

Pain associated with surgical or enzymatic burn wound debridement prevents many burn centres from working outside an operating theatre, creating a burden. Alternatives for general anaesthesia to manage pain in burn patients treated with enzymatic debridements, such as regional anaesthesia, have not been studied in detail. This study explores the different possibilities for pain management during a bedside NexoBrid™ procedure.

MATERIAL AND METHODS

We performed a single-centre retrospective study that included 82 paediatric, adolescent, and adult patients with deep dermal and full-thickness burns treated bedside with NexoBrid™ under regional or general anaesthesia. Outcome measures were pain during the NexoBrid™ procedure, the safety of the anaesthesia and the NexoBrid™ procedure, logistics of the bedside NexoBrid™ procedure, and time to wound closure.

RESULTS

Forty-three patients in the adult group (43/67, 64%) only presented with burn wounds on one upper or the one or two lower extremities. In 29 of them (29/43, 67%), a NexoBrid™ procedure was performed under regional anaesthesia, which resulted in low pain levels without any adverse events. All seven patients in the paediatric group, where only one upper or one or two lower limbs were involved (7/15, 47%), underwent a NexoBrid™ procedure performed under regional anaesthesia where no adverse events were reported. In these children, the use of regional anaesthesia was associated with a significant decrease in time to wound closure (average treatment effect on the treated = -22.5 days, p = 0.021).

CONCLUSION

This study highlights that regional anaesthesia administered at the bedside should be the method of choice for pain management during NexoBrid™ procedures because often, it can be adequately and safely performed in all age groups. This approach will reduce the burden on operating theatres. A flow chart has been developed to guide pain management during a NexoBrid™ procedure.

Surgical Infection Society Research Priorities: A Narrative Review of Fourteen Years of Progress

Background: In 2006, the Surgical Infection Society (SIS) utilized a modified Delphi approach to define 15 specific priority research questions that remained unanswered in the field of surgical infections. The aim of the current study was to evaluate the scientific progress achieved during the ensuing period in answering each of the 15 research questions and to determine if additional research in these fields is warranted. Methods: For each of the questions, a literature search using the National Center for Biotechnology Information (NCBI) was performed by the Scientific Studies Committee of the SIS to identify studies that attempted to address each of the defined questions. This literature was analyzed and summarized. The data on each question were evaluated by a surgical infections expert to determine if the question was answered definitively or remains unanswered. Results: All 15 priority research questions were studied in the last 14 years; six questions (40%) were definitively answered and 9 questions (60%) remain unanswered in whole or in part, mainly because of the low quality of the studies available on this topic. Several of the 9 unanswered questions were deemed to remain research priorities in 2020 and warrant further investigation. These included, for example, the role of empiric antimicrobial agents in nosocomial infections, the use of inotropes/vasopressors versus volume loading to raise the mean arterial pressure, and the role of increased antimicrobial dosing and frequency in the obese patient. Conclusions: Several surgical infection-related research questions prioritized in 2006 remain unanswered. Further high-quality research is required to provide a definitive answer to many of these priority knowledge gaps. An updated research agenda by the SIS is warranted at this time to define research priorities for the future.

Value of Combination of Heart, Lung, and Diaphragm Ultrasound in Predicting Weaning Outcome of Mechanical Ventilation

Background

Postextubation distress is detrimental to the prognosis of critically ill patients with successful spontaneous breathing trial. The known risk factors of failed weaning are associated with the heart, lungs, and diaphragm. The aim of this study was to explore the role of a combined model including indicators of heart, lung, and diaphragm ultrasound in predicting the weaning outcome.

Material/Methods

Patients’ clinical data and ultrasonic features of heart, lungs, and diaphragm were recorded. Patients were included in either the failed weaning group (n=24) or the successful weaning group (n=81). The association of potential variables with the risk of weaning failure was determined using multivariate logistic regression analysis. The accuracy of potential indicators for predicting the weaning outcome were evaluated and a multiindicator combined model was established to improve the predictive accuracy.

Results

Brain natriuretic peptide (odds ratio [OR]=1.120, P=0.004), left-atrial pressure (LAP) (OR=1.333, P=0.005), lung ultrasound score (LUS) (OR=1.736, P=0.001), and hemidiaphragm dysfunction (OR=3.942, P=0.014) were associated with an increased risk of weaning failure. However, all of these indicators could not accurately predict the weaning outcome independently (all areas under the curve [AUCs] <0.9). The combination of LAP, LUS, and hemidiaphragm dysfunction showed the highest AUC (AUC=0.919).

Conclusions

The combined model including LAP, LUS, and hemidiaphragm dysfunction were the most accurate method for the prediction.

Descriptive Analysis of Extubations Performed in an Emergency Department-based Intensive Care Unit

Introduction

Extubation of appropriate patients in the emergency department (ED) may be a strategy to avoid preventable or short-stay intensive care unit (ICU) admissions, and could allow for increased ventilator and ICU bed availability when demand outweighs supply. Extubation is infrequently performed in the ED, and a paucity of outcome data exists. Our objective was to descriptively analyze characteristics and outcomes of patients extubated in an ED-ICU setting.

Methods

We conducted a retrospective observational study at an academic medical center in the United States. Adult ED patients extubated in the ED-ICU from 2015–2019 were retrospectively included and analyzed.

Results

We identified 202 patients extubated in the ED-ICU; 42% were female and median age was 60.86 years. Locations of endotracheal intubation included the ED (68.3%), outside hospital ED (23.8%), and emergency medical services/prehospital (7.9%). Intubations were performed for airway protection (30.2%), esophagogastroduodenoscopy (27.7%), intoxication/ingestion (17.3%), respiratory failure (13.9%), seizure (7.4%), and other (3.5%). The median interval from ED arrival to extubation was 9.0 hours (interquartile range 6.2–13.6). One patient (0.5%) required unplanned re-intubation within 24 hours of extubation. The attending emergency physician (EP) at the time of extubation was not critical care fellowship trained in the majority (55.9%) of cases. Sixty patients (29.7%) were extubated compassionately; 80% of these died in the ED-ICU, 18.3% were admitted to medical-surgical units, and 1.7% were admitted to intensive care. Of the remaining patients extubated in the ED-ICU (n = 142, 70.3%), zero died in the ED-ICU, 61.3% were admitted to medical-surgical units, 9.9% were admitted to intensive care, and 28.2% were discharged home from the ED-ICU.

Conclusion

Select ED patients were safely extubated in an ED-ICU by EPs. Only 7.4% required ICU admission, whereas if ED extubation had not been pursued most or all patients would have required ICU admission. Extubation by EPs of appropriately screened patients may help decrease ICU utilization, including when demand for ventilators or ICU beds is greater than supply. Future research is needed to prospectively study patients appropriate for ED extubation.

Antimicrobial Stewardship and Intensive Care Unit Mortality: A Systematic Review

BACKGROUND

Antimicrobial stewardship programs (ASPs) using audit and feedback in the intensive care unit (ICU) setting can reduce harms related to inappropriate antibiotic use. However, inappropriate discontinuation or narrowing of antibiotic treatment could increase infection-related mortality in this population. Individual ASP studies are underpowered to detect differences in mortality.

METHODS

We conducted a systematic review and meta-analysis of audit and feedback in the ICU setting, using mortality as our outcome.

RESULTS

Of 2447 citations, 11 studies met our inclusion criteria. Although a variety of study designs were used to assess reductions in antibiotic use, mortality was analyzed using an uncontrolled before-after study design in all studies. Five studies directed audit and feedback to all or most ICU patients receiving antibiotics and measured overall ICU mortality. In the meta-analysis of these studies, the pooled relative risk of ICU mortality was 1.03 (95% confidence interval, .93-1.14). A second meta-analysis of 3 smaller studies that evaluated mortality only in patients directly assessed by the ASP found a pooled relative risk of ICU mortality of 1.06 (95% confidence interval, .80 to 1.4). Three studies were not appropriate for meta-analysis, but their results were consistent with our overall findings.

CONCLUSIONS

Our systematic review did not identify a change in mortality associated with antimicrobial stewardship using audit and feedback in the ICU setting. These results increase our confidence that audit and feedback can be safely implemented in this setting. Future studies should report standardized estimates of mortality and use more robust study designs to assess mortality, when feasible.

Comparative study of 2 oral care protocols in intensive care units

BACKGROUND

The quality of oral care is important in limiting the emergence of ventilator-associated pneumonia (VAP) in intubated patients. Our main objective was to measure the quality improvement in oral care following the implementation of a new oral care protocol. We also monitored VAP rates.

MATERIAL/METHODS

This was a cohort study of patients in 5 adult ICUs covering different specialties. During period 1, caregivers used a foam stick for oral care and during period 2 a stick and tooth brushing with aspiration. Oral chlorhexidine was used during both periods. The caregivers rated improvement in oral health on the basis of 4 criteria (tongue, mucous membranes, gingivae, and teeth). Caregiver satisfaction was also assessed. The incidence of VAP was monitored.

RESULTS

A total of 2,030 intubated patients admitted to intensive care units benefited from oral care. The patient populations during the 2 periods were similar with regard to demographic data and VAP potential risk factors. Oral health was significantly better from the third day of oral care in period 2 onward (period 1, 6.4 ± 2.1; period 2, 5.6 ± 1.8; P = .043). Caregivers found the period 2 protocol easier to implement and more effective. VAP rates decreased significantly between the 2 periods (period 1, 12.8%; period 2, 8.5%; P = .002).

CONCLUSIONS

Our study showed that the implementation of a simple strategy improved the quality of oral care of patients in intensive care units, and decreased VAP rates.

The Clinical Impact of Ventilator-Associated Events: A Prospective Multi-Center Surveillance Study

OBJECTIVE

The Centers for Disease Control and Prevention (CDC) has developed an approach to ventilator-associated events (VAE) surveillance. Using these methods, this study was performed to investigate VAE incidences and to test whether VAEs are associated with poorer outcomes in China.

DESIGN

A 4-month, prospective multicenter surveillance study between April and July 2013.

SETTING

Our study included 15 adult intensive care units (ICUs) of 15 hospitals in China.

PATIENTS

Patients admitted to ICUs during the study period

METHODS

Patients on mechanical ventilation (MV) were monitored for VAEs: ventilator-associated conditions (VACs), infection-related ventilator-associated complications (IVACs), and possible or probable ventilator-associated pneumonia (VAP). Patients with and without VACs were compared with regard to duration of MV, ICU length of stay (LOS), overall hospital LOS, and mortality rate.

RESULTS

During the study period, 2,356 of the 5,256 patients admitted to ICUs received MV for 8,438 ventilator days. Of these patients, 636 were on MV >2 days. VACs were identified in 94 cases (4.0%; 11.1 cases per 1,000 ventilator days), including 31 patients with IVACs and 16 with possible VAP but none with probable VAP. Compared with patients without VACs, patients with VACs had longer ICU LOS (by 6.2 days), longer duration on MV (by 7.7 days), and higher hospital mortality rate (50.0% vs 27.3%). The mortality rate attributable to VACs was 11.7%. Compared with those with VACs alone, patients with IVACs had longer duration on MV and increased ICU LOS but no higher mortality rates.

CONCLUSIONS

In China, surveillance of VACs and IVACs is able to identify MV patients with poorer outcomes. However, surveillance of possible and probable VAP can be problematic.

Managing endotracheal tube cuff pressure at altitude: a comparison of four methods

BACKGROUND

Ascent to altitude results in the expansion of gases in closed spaces. The management of overinflation of the endotracheal tube (ETT) cuff at altitude is critical to prevent mucosal injury.

METHODS

We continuously measured ETT cuff pressures during a Critical Care Air Transport Team training flight to 8,000-ft cabin pressure using four methods of cuff pressure management. ETTs were placed in a tracheal model, and mechanical ventilation was performed. In the control ETT, the cuff was inflated to 20 mm Hg to 22 mm Hg and not manipulated. The manual method used a pressure manometer to adjust pressure at cruising altitude and after landing. A PressureEasy device was connected to the pilot balloon of the third tube and set to a pressure of 20 mm Hg to 22 mm Hg. The final method filled the balloon with 10 mL of saline. Both size 8.0-mm and 7.5-mm ETT were studied during three flights.

RESULTS

In the control tube, pressure exceeded 70 mm Hg at cruising altitude. Manual management corrected for pressure at altitude but resulted in low cuff pressures upon landing (<10 mm Hg). The PressureEasy reduced the pressure change to a maximum of 36 mm Hg, but on landing, cuff pressures were less than 15 mm Hg. Saline inflation ameliorated cuff pressure changes at altitude, but initial pressures were 40 mm Hg.

CONCLUSION

None of the three methods using air inflation managed to maintain cuff pressures below those associated with tracheal damage at altitude or above pressures associated with secretion aspiration during descent. Saline inflation minimizes altitude-related alteration in cuff pressure but creates excessive pressures at sea level. New techniques need to be developed.

The potential role of nano- and micro-technology in the management of critical illnesses

In recent years nanomedicine has become an attractive concept for the targeted delivery of therapeutic and diagnostic compounds to injured or inflamed organs. Nanoscale drug delivery systems have the ability to improve the pharmacokinetics and increase the biodistribution of therapeutic agents to target organs, thereby resulting in improved efficacy and reduced drug toxicity. These systems are exploited for therapeutic purposes to carry the drug in the body in a controlled manner from the site of administration to the therapeutic target. The mortality in many of the critical illnesses such as sepsis and acute respiratory distress syndrome continues to remain high despite of an increased understanding of the molecular pathogenesis of these diseases. Several promising targets that have been identified as potential therapies for these devastating diseases have been limited because of difficulty with delivery systems. In particular, delivery of peptides, proteins, and miRNAs to the lung is an ongoing challenge. Hence, it is an attractive strategy to test potential targets by employing nanotechnology. Here some of the novel nanomedicine approaches that have been proposed and studied in recent years to facilitate the delivery of therapeutic agents in the setting of critical illnesses such as acute respiratory distress syndrome, sepsis and ventilator associated pneumonia are reviewed.

Impact of appropriate antimicrobial treatment on transition from ventilator-associated tracheobronchitis to ventilator-associated pneumonia

Introduction

Two small randomized controlled trials have suggested beneficial effects of antibiotic treatment in patients with ventilator-associated tracheobronchitis (VAT). The primary aim of this study is to determine the impact of appropriate antibiotic treatment on transition from VAT to ventilator-associated pneumonia (VAP) in critically ill patients. The secondary objective was to determine the incidence of VAP in patients with VAT.

Methods

This was a prospective observational multicenter study. All patients with a first episode of VAT were eligible. Patients with tracheostomy at intensive care unit (ICU) admission, and those with VAP prior to VAT were excluded. VAT was defined using all the following criteria: fever > 38°C with no other cause, purulent tracheal secretions, positive tracheal aspirate (≥10⁵ cfu/mL), and absence of new infiltrate on chest X ray. Only VAP episodes diagnosed during the 96 h following VAT, and caused by the same bacteria, were taken into account. Antibiotic treatment was at the discretion of attending physicians. Risk factors for transition from VAT to VAP were determined using univariate and multivariate analysis. All variables from univariate analysis with P values <0.1 were incorporated in the multivariate logistic regression analysis.

Results

One thousand seven hundred and ten patients were screened for this study. Eighty-six, and 123 patients were excluded for tracheostomy at ICU admission, and VAP prior to VAT; respectively. One hundred and twenty two (7.1%) patients were included. 17 (13.9%) patients developed a subsequent VAP. The most common microorganisms in VAT patients were Pseudomonas aeruginosa (30%), Staphylococcus aureus (18%), and Acinetobacter baumannii (10%). Seventy-four (60%) patients received antimicrobial treatment, including 58 (47.5%) patients who received appropriate antimicrobial treatment. Appropriate antibiotic treatment was the only factor independently associated with reduced risk for transition from VAT to VAP (OR [95% CI] 0.12[0.02-0.59], P = 0.009). The number of patients with VAT needed to treat to prevent one episode of VAP, or one episode of VAP related to P. aeruginosa was 5, and 34; respectively.

Conclusions

Appropriate antibiotic treatment is independently associated with reduced risk for transition from VAT to VAP.

Clinician practice and the National Healthcare Safety Network definition for the diagnosis of catheter-associated urinary tract infection

BACKGROUND

The National Healthcare Safety Network (NHSN) definition for catheter-associated urinary tract infection (CAUTI) is used to evaluate improvements in CAUTI prevention efforts. We assessed whether clinician practice was reflective of the NHSN definition.

METHODS

We evaluated all adult inpatients hospitalized between July 2010 and June 2011, with a first positive urine culture > 48 hours of admission obtained while catheterized or within 48 hours of catheter discontinuation. Data comprised patients' signs, symptoms, and diagnostic tests; clinician's diagnosis; and the impression of the infectious diseases (ID) consultant. The clinician's practice was compared with the NHSN definition and the ID consultant's impression.

RESULTS

Antibiotics were initiated by clinicians to treat CAUTI in 216 of 387 (55.8%) cases, with 119 of 387 (30.7%) fitting the NHSN CAUTI definition, and 63 of 211 (29.9%) considered by ID to have a CAUTI. The sensitivity, specificity, and positive and negative predictive values of a clinician diagnosis of CAUTI were 62.2%, 47%, 34.3%, and 73.7% when compared with NHSN CAUTI definition (n = 387) and 100%, 57.4%, 50%, and 100% when compared with the ID consultant evaluation (n = 211), respectively. The positive predictive value of the NHSN CAUTI definition was 35.1% when compared with the ID consultant's impression (n = 211).

CONCLUSION

NHSN CAUTI definition did not reflect clinician or ID consultant practices. Our findings reflect the differences between surveillance definitions and clinical practice.

Pouring salt on a wound: Pseudomonas aeruginosa virulence factors alter Na+ and Cl- flux in the lung

Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen with multiple niches in the human body, including the lung. P. aeruginosa infections are particularly damaging or fatal for patients with ventilator-associated pneumonia, chronic obstructive pulmonary disease, and cystic fibrosis (CF). To establish an infection, P. aeruginosa relies on a suite of virulence factors, including lipopolysaccharide, phospholipases, exoproteases, phenazines, outer membrane vesicles, type III secreted effectors, flagella, and pili. These factors not only damage the epithelial cell lining but also induce changes in cell physiology and function such as cell shape, membrane permeability, and protein synthesis. While such virulence factors are important in initial infection, many become dysregulated or nonfunctional during the course of chronic infection. Recent work on the virulence factors alkaline protease (AprA) and CF transmembrane conductance regulator inhibitory factor (Cif) show that P. aeruginosa also perturbs epithelial ion transport and osmosis, which may be important for the long-term survival of this microbe in the lung. Here we discuss the literature regarding host physiology-altering virulence factors with a focus on Cif and AprA and their potential roles in chronic infection and immune evasion.