Noninvasive respiratory support in the perioperative period

Comparison of automatic versus constant CPAP in elderly patients after major abdominal surgery: a randomized noninferiority trial

BACKGROUND

Geriatric patients undergoing major open abdominal surgery are at high risk for postoperative pulmonary complications and hypoxemia. Continuous Positive Airway Pressure (CPAP) after surgery may improve postoperative lung function. This randomized controlled trial compared two CPAP techniques ‒ automatic via nasal mask and constant via facial mask ‒ regarding pulmonary function and patient tolerance.

METHODS

Sixty patients (≥ 60 years) were randomized (1:1) to receive either automatic CPAP (2-10 cm H2O) via a nasal mask (Group A) or constant CPAP (7.5 cm H2O) via a facial mask (Group C) upon arrival in the post-anesthesia care unit. Oxygenation (PaO2, PaO₂/FiO₂, SpO2) and spirometry (FVC, FEV1, PEF) were assessed preoperatively, postoperatively, and one hour after treatment. Comfort scores (0-10, with 0 indicating the best comfort) and complications were recorded.

RESULTS

PaO₂/FiO2 improvement was lower in Group A (32.6 ± 26.3 mmHg) than in Group C (52.9 ± 40.1 mmHg; p = 0.023). FVC improvement was also lower in Group A (3.7% ± 4.0%) than in Group C (6.7% ± 4.9%; p = 0.012). However, Group A had better tolerance, with lower comfort scores (2 [2-3] vs. 3 [2-4], p = 0.002). Pulmonary function benefits were more pronounced in patients over 70 and those undergoing upper abdominal surgery.

CONCLUSION

Both CPAP techniques prevent pulmonary decline in geriatric patients post-surgery. While automatic CPAP provides better comfort, constant CPAP improves oxygenation. Although our findings are short-term, they suggest that CPAP mode selection should be tailored based on patient-specific needs.

Debunking a mythology: Atelectasis is not a cause of postoperative fever

Most physicians appreciate that practicing medicine is a commitment to continuous learning. However, "learning" can be mistakenly understood as simply the acquisition of facts and new knowledge. But learning also necessitates the constant re-examination and challenging of one's existing body of knowledge, as misinformation persists when one's beliefs are not challenged or questioned in the light of new information. One example is the pervasive belief that postoperative atelectasis causes fever despite ample evidence to the contrary. Herein we examine the imaging characteristics of atelectasis, and the means of differentiation of atelectasis from consolidation. We also explore the history of this persistent myth and review the existing literature on the actual causes of postoperative fever.

Noninvasive respiratory support in the perioperative setting: a narrative review

The application of preoperative noninvasive respiratory support (NRS) has been expanding with increasing recognition of its potential role in this setting as a physiological optimization for patients with a high risk of developing atelectasis and postoperative pulmonary complications (PPC). The increased availability of high-performance anesthesia ventilator machines providing an easy way for NRS support in patients with reduced lung function should not be under-evaluated. This support can reduce hypoxia, restore lung volumes and theoretically reduce atelectasis formation after general anesthesia. Therapeutic purposes should also be considered in the perioperative setting, such as preoperative NRS to optimize treatment of patients' pre-existing diseases, e.g., sleep-disordered breathing. Finally, the recent guidelines for airway management suggest preoperative NRS application before anesthesia induction in difficult airway management to prolong the time needed to secure the airway with an orotracheal tube. This narrative review aims to revise all these aspects and to provide some practical notes to maximize the efficacy of perioperative noninvasive respiratory support.

Negative pressure pulmonary edema following laryngospasm after dental abscess: A case report

Negative pressure pulmonary edema (NPPE), also known as post-obstructive pulmonary edema, is a rare and life-threatening condition. It occurs when a person breathes against an obstructed glottis, causing negative thoracic pressure in the lungs. This negative pressure can lead to fluid accumulation in the lungs, resulting in pulmonary edema. The obstructed glottis might be caused by laryngospasm, which occurs when the muscles around the larynx involuntarily spasm and can lead to complete upper airway occlusion. This report shares the case of a 33-year-old woman hospitalized for periapical dental abscess, facial swelling, and shortness of breath. The patient exhibited signs of poor oral hygiene. After the exacerbation of her symptoms, she showed signs of asphyxia and decreased oxygen saturation, which led to her intubation. Imaging revealed bilateral pleural effusion and patchy ground glass opacities favoring NPPE. After three days of treatment with diuretics and other conservative measures, her condition was alleviated, and she was extubated. Laryngospasm in the presence of a dental abscess is uncommon. Identification of imaging favoring NPPE in this setting is even more rare. In cases of laryngospasm, prompt intubation is crucial. Therapy with diuretics and other conservative measures can effectively treat NPPE following laryngospasm.

The role of prophylactic administration of CPAP in general surgical wards after open visceral surgery in reducing postoperative pneumonia-a retrospective cohort study

BACKGROUND

Postoperative pneumonia is a main adverse event that causes increased postoperative morbidity and prolonged length of hospital stay leading to high postoperative mortality. Continuous positive airway pressure (CPAP) is a type of non-invasive ventilation for the delivery of a positive airway pressure during respiration. In this study, we evaluated the impact of postoperative prophylactic CPAP on prevention of pneumonia in patients after open visceral surgery.

METHODS

In this observational cohort study, we compared the rates of postoperative pneumonia in patients who underwent open major visceral surgery from January 2018 till August 2020 in the study and control group. The study group had postoperative prophylactic sessions of CPAP for 15 min, 3-5 times a day and a repeated spirometer training was also performed in the general surgical ward. The control group received only the postoperative spirometer training as a prophylactic measure against postoperative pneumonia. The chi-square test was used to measure the relationships between categorical variables, and a binary regression analysis determined the correlation between independent and dependent variables.

RESULTS

A total of 258 patients met the inclusion criteria who had open visceral surgery for various clinical illnesses. There were 146 men (56.6%) and 112 women with a mean age of 68.62 years. As many as 142 patients received prophylactic CPAP and they were grouped into the study group, whereas 116 patients without prophylactic CPAP were placed in the control group. Overall, the rate of postoperative pneumonia was significantly less in the study group (5.6% vs. 25.9% in the control group; p-value < 0.0001), which could be confirmed by the regression analysis (OR 0.118, CI 95% 0.047-0.295, p < 0.001).

CONCLUSION

Postoperative intermittent CPAP after open visceral surgery can be performed in a general surgical ward. Our study showed a significant association with a low rate of postoperative pneumonia, especially in high-risk patients. This leads to a significantly shorter postoperative hospital stay especially in high-risk patients after upper gastrointestinal surgery.

TRIAL REGISTRATION NUMBER

DRKS00028988, 04.05.2022, retrospectively registered.

High-flow nasal cannula reduces intubation rate in patients with COVID-19 with acute respiratory failure: a meta-analysis and systematic review

OBJECTIVE

This study aimed to investigate the effect of high-flow nasal cannula therapy (HFNC) versus conventional oxygen therapy (COT) on intubation rate, 28-day intensive care unit (ICU) mortality, 28-day ventilator-free days (VFDs) and ICU length of stay (ICU LOS) in adult patients with acute respiratory failure (ARF) associated with COVID-19.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Web of Science, Cochrane Library and Embase up to June 2022.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Only randomised controlled trials or cohort studies comparing HFNC with COT in patients with COVID-19 were included up to June 2022. Studies conducted on children or pregnant women, and those not published in English were excluded.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently screened the titles, abstracts and full texts. Relevant information was extracted and curated in the tables. The Cochrane Collaboration tool and Newcastle-Ottawa Scale were used to assess the quality of randomised controlled trials or cohort studies. Meta-analysis was conducted using RevMan V.5.4 computer software using a random effects model with a 95% CI. Heterogeneity was assessed using Cochran's Q test (χ²) and Higgins I² statistics, with subgroup analyses to account for sources of heterogeneity.

RESULTS

Nine studies involving 3370 (1480 received HFNC) were included. HFNC reduced the intubation rate compared with COT (OR 0.44, 95% CI 0.28 to 0.71, p=0.0007), decreased 28-day ICU mortality (OR 0.54, 95% CI 0.30 to 0.97, p=0.04) and improved 28-day VFDs (mean difference (MD) 2.58, 95% CI 1.70 to 3.45, p<0.00001). However, HFNC had no effect on ICU LOS versus COT (MD 0.52, 95% CI -1.01 to 2.06, p=0.50).

CONCLUSIONS

Our study indicates that HFNC may reduce intubation rate and 28-day ICU mortality, and improve 28-day VFDs in patients with ARF due to COVID-19 compared with COT. Large-scale randomised controlled trials are necessary to validate our findings.

PROSPERO REGISTRATION NUMBER

CRD42022345713.

Comparing the effects of continuous positive airway pressure via mask or helmet interface on oxygenation and pulmonary complications after major abdominal surgery: a randomized trial

The risk of pulmonary complications is high after major abdominal surgery but may be reduced by prophylactic postoperative noninvasive ventilation using continuous positive airway pressure (CPAP). This study compared the effects of intermittent mask CPAP (ICPAP) and continuous helmet CPAP (HCPAP) on oxygenation and the risk of pulmonary complications following major abdominal surgery. Patients undergoing open abdominal aortic aneurysm repair or pancreaticoduodenectomy were randomized (1:1) to either postoperative ICPAP or HCPAP. Oxygenation was evaluated as the partial pressure of oxygen in arterial blood fraction of inspired oxygen ratio (PaO₂/FIO₂) at 6 h, 12 h, and 18 h postoperatively. Pulmonary complications were defined as X-ray verified pneumonia/atelectasis, clinical signs of pneumonia, or supplementary oxygen beyond postoperative day 3. Patient-reported comfort during CPAP treatment was also evaluated. In total, 96 patients (ICPAP, n = 48; HCPAP, n = 48) were included, and the type of surgical procedure were evenly distributed between the groups. Oxygenation did not differ between the groups by 6 h, 12 h, or 18 h postoperatively (p = 0.1, 0.08, and 0.67, respectively). Nor was there any difference in X-ray verified pneumonia/atelectasis (p = 0.40) or supplementary oxygen beyond postoperative day 3 (p = 0.53). Clinical signs of pneumonia tended to be more frequent in the ICPAP group (p = 0.06), yet the difference was not statistically significant. Comfort scores were similar in both groups (p = 0.43), although a sensation of claustrophobia during treatment was only experienced in the HCPAP group (11% vs. 0%, p = 0.03). Compared with ICPAP, using HCPAP was associated with similar oxygenation (i.e., PaO₂/FIO₂ ratio) and a similar risk of pulmonary complications. However, HCPAP treatment was associated with a higher sensation of claustrophobia.

Postoperative prophylactic intermittent noninvasive ventilation versus usual postoperative care for patients at high risk of pulmonary complications: a multicentre randomised trial

BACKGROUND

Pulmonary complications are an important cause of morbidity and mortality after surgery. We evaluated the clinical effectiveness of noninvasive ventilation (NIV) in preventing postoperative acute respiratory failure.

METHODS

This is an open, multicentre randomised trial that included patients at high risk of postoperative pulmonary complications after elective or semi-urgent surgery with an Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) score ≥45. Patients were randomly assigned to intermittent prophylactic face-mask NIV for 6-8 h day^-1 or usual postoperative care. The primary outcome was in-hospital acute respiratory failure within 7 days after surgery. Patients who underwent surgery and postoperative extubation were included in the modified intended-to-treat analysis. Results are presented as n (%) and odds ratios (ORs) with 95% confidence intervals.

RESULTS

Between November 2017 and October 2019, 266 patients were randomised and 253 included in the main analysis. Of these, 203 (80.2%) were male with a mean age of 68 (11) yr and an ARISCAT score of 53 (6); 237 subjects (93.7%) underwent cardiac or thoracic surgery. There were 125 patients allocated to prophylactic NIV and 128 to usual care. Unplanned treatment termination occurred in 58 subjects in the NIV group, which was linked to NIV discomfort for 36 subjects. There was no difference in the incidence of the primary outcome of postoperative acute respiratory failure between treatment groups (NIV: 30 of 125 subjects [24.0%] vs usual care: 35 of 128 subjects [27.3%]; OR 0.97 [0.90-1.04]; P=0.54).

CONCLUSIONS

Prophylactic NIV was difficult to implement after high-risk surgery because of low patient compliance. Prophylactic NIV did not prevent acute respiratory failure.

CLINICAL TRIAL REGISTRATION

NCT03629431 and EudraCT 2017-001011-36.

Perioperative oxygen therapy: a protocol for an overview of systematic reviews and meta-analyses

BACKGROUND

Oxygen is routinely given to patients during and after surgery. Perioperative oxygen administration has been proposed as a potential strategy to prevent and treat hypoxaemia and reduce complications, such as surgical site infections, pulmonary complications and mortality. However, uncertainty exists as to which strategies in terms of amount, delivery devices and timing are clinically effective. The aim of this overview of systematic reviews and meta-analyses is to answer the research question, 'For which types of surgery, at which stages of care, in which sub-groups of patients and delivered under what conditions are different types of perioperative oxygen therapy clinically effective?'.

METHODS

We will search key electronic databases (MEDLINE, EMBASE, the Cochrane Database of Systematic Reviews, CENTRAL, Epistemonikos, PROSPERO, the INAHTA International HTA Database and DARE archives) for systematic reviews and randomised controlled trials comparing perioperative oxygen strategies. Each review will be mapped according to type of surgery, surgical pathway timepoints and clinical comparison. The highest quality reviews with the most comprehensive and up-to-date coverage of relevant literature will be chosen as anchoring reviews. Standardised data will be extracted from each chosen review, including definition of oxygen therapy, summaries of interventions and comparators, patient population, surgical characteristics and assessment of overall certainty of evidence. For clinical outcomes and adverse events, the overall pooled findings and results of subgroup and sensitivity analyses (where available) will be extracted. Trial-level data will be extracted for surgical site infections, mortality, and potential trial-level effect modifiers such as risk of bias, outcome definition and type of surgery to facilitate quantitative data analysis. This analysis will adopt a multiple indication review approach with panoramic meta-analysis using review-level data and meta-regression using trial-level data. An evidence map will be produced to summarise our findings and highlight any research gaps.

DISCUSSION

There is a need to provide a panoramic overview of systematic reviews and meta-analyses describing peri-operative oxygen practice to both inform clinical practice and identify areas of ongoing uncertainty, where further research may be required. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42021272361.

The effect of postoperative respiratory and mobilization interventions on postoperative complications following abdominal surgery: a systematic review and meta-analysis

PURPOSE

Up to 30% of patients undergoing abdominal surgery suffer from postoperative pulmonary complications. The purpose of this systematic review and meta-analyses was to investigate whether postoperative respiratory interventions and mobilization interventions compared with usual care can prevent postoperative complications following abdominal surgery.

METHODS

The review was conducted in line with PRISMA and GRADE guidelines. MEDLINE, Embase, and PEDRO were searched for randomized controlled trials and observational studies comparing postoperative respiratory interventions and mobilization interventions with usual care in patients undergoing abdominal surgery. Meta-analyses with trial sequential analysis on the outcome pulmonary complications were performed. Review registration: PROSPERO (identifier: CRD42019133629) RESULTS: Pulmonary complications were addressed in 25 studies containing 2068 patients. Twenty-three studies were included in the meta-analyses. Patients predominantly underwent open elective upper abdominal surgery. Postoperative respiratory interventions consisted of expiratory resistance modalities (CPAP, EPAP, BiPAP, NIV), assisted inspiratory flow modalities (IPPB, IPAP), patient-operated ventilation modalities (spirometry, PEP), and structured breathing exercises. Meta-analyses found that ventilation with high expiratory resistance (CPAP, EPAP, BiPAP, NIV) reduced the risk of pulmonary complications with OR 0.42 (95% CI 0.18-0.97, p = 0.04, I2 = 0%) compared with usual care, however, the trial sequential analysis revealed that the required information size was not met. Neither postoperative assisted inspiratory flow therapy, patient-operated ventilation modalities, nor breathing exercises reduced the risk of pulmonary complications.

CONCLUSION

The use of postoperative expiratory resistance modalities (CPAP, EPAP, BiPAP, NIV) after abdominal surgery might prevent pulmonary complications and it seems the preventive abilities were largely driven by postoperative treatment with CPAP.

The effect of immediate postoperative Boussignac CPAP on adverse pulmonary events after thoracic surgery: A multicentre, randomised controlled trial

BACKGROUND

The effectiveness of prophylactic continuous positive pressure ventilation (CPAP) after thoracic surgery is not clearly established.

OBJECTIVE

The aim of this study was to assess the effectiveness of CPAP immediately after lung resection either by thoracotomy or thoracoscopy in preventing atelectasis and pneumonia.

DESIGN

A multicentre, randomised, controlled, open-label trial.

SETTINGS

Four large University hospitals at Madrid (Spain) from March 2014 to December 2016.

PATIENTS

Immunocompetent patients scheduled for lung resection, without previous diagnosis of sleep-apnoea syndrome or severe bullous emphysema. Four hundred and sixty-four patients were assessed, 426 were randomised and 422 were finally analysed.

INTERVENTION

Six hours of continuous CPAP through a Boussignac system versus standard care.

MAIN OUTCOME MEASURES

Primary outcome: incidence of the composite endpoint 'atelectasis + pneumonia'. Secondary outcome: incidence of the composite endpoint 'persistent air leak + pneumothorax'.

RESULTS

The primary outcome occurred in 35 patients (17%) of the CPAP group and in 58 (27%) of the control group [adjusted relative risk (ARR) 0.53, 95% CI 0.30 to 0.93]. The secondary outcome occurred in 33 patients (16%) of the CPAP group and in 29 (14%) of the control group [ARR 0.92, 95% CI 0.51 to 1.65].

CONCLUSION

Prophylactic CPAP decreased the incidence of the composite endpoint 'postoperative atelectasis + pneumonia' without increasing the incidence of the endpoint 'postoperative persistent air leaks + pneumothorax'.

Safety of changes in the use of noninvasive ventilation and high flow oxygen therapy on reintubation in a surgical intensive care unit: A retrospective cohort study

Reintubation after weaning from mechanical ventilation is relatively common and is associated with poor outcomes. Different methods to decrease the reintubation rate post extubation, including noninvasive ventilation, and more recently high-flow oxygen (HFO) therapy, have been proposed. In this study, we aimed to assess the safety of introducing HFO in the post-extubation care of intensive care unit (ICU) patients. We conducted a single-center cohort study of extubated adult patients hospitalized in a surgical ICU and previously mechanically ventilated for > 1 day. Our study consisted of two phases: Phase 1 (before the introduction of HFO from April 2015 to April 2016) and Phase P2 (after the introduction of HFO from April 2017 to April 2018). The primary endpoint was the reintubation rate within 48 hours of extubation. In total, 290 patients (median age 65 years [50–74]; 190 men [65.5%]) were included in the analysis (181 and 109 in Phases 1 and 2, respectively). The results of the post-extubation use of noninvasive methods (noninvasive ventilation and/or HFO) were not significantly different between the two phases (41 [22.7%] versus 29 [26.6%] patients; p = 0.480), however these methods were implemented earlier in Phase 2 (0 versus 4 hours; p = 0.009) and HFO was used significantly more often than noninvasive ventilation (24 [22.0%] versus 25 [13.8%] patients; p = 0.039). The need for reintubation within 48 hours post extubation was significantly lower in Phase 2 (4 [3.7%] versus 20 [11.0%] patients; p = 0.028) but was not significantly different at 7 days post extubation (10 [9.2%] versus 30 [16.6%] patients; p = 0.082). The earlier implementation of noninvasive methods and the increased use of HFO beginning in Phase 2 were safe and effective based on the reintubation rates within the first 48 hours post extubation and after 7 days.

THE DETECTION AND ESTIMATION OF THE AIR LEAKAGE IN NONINVASIVE VENTILaTION: PLATFORM STUDY

Although noninvasive ventilation has been increasingly used in clinics and homes to treat respiratory diseases, the problem of air leaks should not be neglected because they may affect the performance of the ventilation and even pose a threat to life. The detection and estimation of the leakage are required to implement auto-compensation, which is important in the development of intelligent ventilation. In this study, the methods of detection and estimation of the leakage were established and validated. Ventilation experiments were performed based on the established experimental platform. The air flow and pressure were detected at different locations of the airway to determine the relationship between the leakage and the other variables. The leakage was estimated using linear predictor models. The curves describing the relationships among pressure, flow and volume changed regularly with the leakage. For pressure-controlled ventilation, the leakage could be estimated by the detected peak flow and by the ventilation volume of one breathing cycle. The methods for the leakage estimation were validated. Volume-controlled ventilation was also studied. Although the leakage could be estimated using the detected peak pressure, the limitation of volume-controlled ventilation was obvious for noninvasive ventilation (NIV). Leaks could be detected and estimated using a linear predictor model via the flow/pressure curve. The use of this model is a potential method for the auto-compensation of noninvasive ventilation.

Helmet continuous positive airway pressure versus high-flow nasal cannula in COVID-19: a pragmatic randomised clinical trial (COVID HELMET)

BACKGROUND

Patients with COVID-19 and hypoxaemia despite conventional low-flow oxygen therapy are often treated with high-flow nasal cannula (HFNC) in line with international guidelines. Oxygen delivery by helmet continuous positive airway pressure (CPAP) is a feasible option that enables a higher positive end-expiratory pressure (PEEP) and may theoretically reduce the need for intubation compared to HFNC but direct comparative evidence is lacking.

METHODS

We plan to perform an investigator-initiated, pragmatic, randomised trial at an intermediate-level COVID-19 cohort ward in Helsingborg Hospital, southern Sweden. We have estimated a required sample size of 120 patients randomised 1:1 to HFNC or Helmet CPAP to achieve 90% power to detect superiority at a 0.05 significance level regarding the primary outcome of ventilator free days (VFD) within 28 days using a Mann-Whitney U test. Patient recruitment is planned to being June 2020 and be completed in the first half of 2021.

DISCUSSION

We hypothesise that the use of Helmet CPAP will reduce the need for invasive mechanical ventilation compared to the use of HFNC without having a negative effect on survival. This could have important implications during the current COVID-19 epidemic.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04395807 . Registered on 20 May 2020.

Postoperative pain therapy with hydromorphone; comparison of patient-controlled analgesia with target-controlled infusion and standard patient-controlled analgesia: A randomised controlled trial

BACKGROUND

The challenge of managing acute postoperative pain is the well tolerated and effective administration of analgesics with a minimum of side effects. The standard therapeutic approach is patient-controlled analgesia (PCA) with systemic opioids. To overcome problems of oscillating opioid concentrations, we studied patient-controlled analgesia by target-controlled infusion (TCI-PCA) as an alternative.

OBJECTIVE

To compare efficacy, safety and side effects of standard PCA with TCI-PCA for postoperative pain therapy with hydromorphone.

DESIGN

Single-blinded, randomised trial.

SETTING

University Hospital, Germany from December 2013 to April 2015.

PARTICIPANTS

Fifty adults undergoing cardiac surgery.

INTERVENTIONS

Postoperative pain therapy on the ICU was managed with intravenous (i.v.) hydromorphone and patients randomised to TCI-PCA with target plasma concentrations between 0.8 and 10 ng ml, or PCA with bolus doses of 0.2 mg. Pain was regularly assessed using the 11-point numerical rating scale (NRS). Blood pressure, heart rate, oxygen saturation and cardiac output were continuously monitored, and adverse events were registered throughout the study.

MAIN OUTCOME MEASURES

NRS pain ratings, hydromorphone doses, haemodynamic effects and side effects.

RESULTS

NRS pain ratings, total doses of hydromorphone and haemodynamic data did not differ significantly between TCI-PCA and PCA. The number of bolus doses during PCA was significantly higher than the number of target increases during TCI-PCA (P = 0.006). The number of negative requests was also significantly higher during PCA than during TCI-PCA (P = 0.02). The respiratory rate on the first postoperative morning was 25 ± 6 min during TCI-PCA, compared with 19 ± 4 min during PCA (P = 0.022). Nausea occurred in 30% after TCI-PCA and 24% after PCA (P = 0.46).

CONCLUSION

TCI-PCA was effective and well tolerated in acute postoperative pain management after cardiac surgery. Further studies are needed to evaluate this approach in clinical practice.

TRIAL REGISTRATION

EudraCT Number: 2013-002875-16, and ClinicalTrials.gov Identifier: NCT02035709.

Pulmonary edema post-adenotonsillectomy in children

Post-adenotonsillectomy pulmonary edema (pATPE) is a life-threatening condition that necessitates immediate clinical intervention. The early diagnosis and detection of the signs of this condition is vital to its treatment and patient outcome. The purpose of this review article is to present epidemiological data on the prevalence of pATPE, and address the mechanisms of development, types, etiology, pathophysiology, and management of pATPE. In order to minimize postoperative intensive care unit admission rates of pATPE, utilization of preoperative clinical assessment, operative/postoperative monitoring tools, and procedural precautions are discussed.

Prophylactic continuous positive airway pressure after pulmonary lobectomy: a randomized controlled trial

Background

Despite advances in perioperative care and surgical techniques, patients undergoing pulmonary lobectomy are still at high risk for postoperative complications. Among interventions expected to reduce complications, continuous positive airway pressure (CPAP) is a discussed option. This trial aims to test the hypothesis whether prophylactic application of CPAP following pulmonary lobectomy can reduce postoperative complications.

Methods

The study was designed as a prospective, randomized, controlled trial. Patients with clinical stage I non-small cell lung cancer scheduled for pulmonary lobectomy were eligible and were trained for the use of CPAP interface. The control group received standard postoperative pain management and physiotherapy; in addition, the study group received CPAP (PEEP 8-12 cmH₂O, 2 hours thrice daily for three days).

Results

After the appropriate selection, 163 patients were considered for the analysis: 82 patients constituted the control group, 81 the study group. The two groups were substantially comparable for preoperative parameters. The rate of postoperative complications was lower in the study group (24.7% vs. 43.9%; P=0.015) as well as the hospital stay (6 vs. 7 days; P=0.031). The stepwise logistic regression model identified: CPAP [odd ratio (OR): 0.3026, CI: 0.1389-0.6591], smoke habits [OR: 2.5835, confidence interval (CI): 1.0331-6.4610] and length of surgery in minutes (OR: 1.0102, CI: 1.0042-1.0163) as regressors on postoperative complications.

Conclusions

The present trial demonstrated that prophylactic application of CPAP during the postoperative period after pulmonary lobectomy for stage I non-small cell lung cancer was effective in prevent postoperative complications.

Relationship between hyperoxemia and ventilator associated pneumonia

Previous studies suggest a relationship between hyperoxemia and ventilator-associated pneumonia (VAP). Hyperoxemia is responsible for denitrogenation phenomena, and inhibition of surfactant production, promoting atelectasis in mechanically ventilated patients. Further, hyperoxemia impairs the efficacy of alveolar macrophages to migrate, phagocyte and kill bacteria. Oxygen can also cause pulmonary-specific toxic effect called hyperoxic acute lung injury leading to longer duration of mechanical ventilation. All these hyperoxic effects are well-known risk factors for VAP. A recent retrospective large single center study identified hyperoxemia as an independent risk factor for VAP. However, two recent randomized controlled trials evaluated the impact of conservative oxygen strategy versus a liberal strategy, but did not confirm the role of hyperoxemia in lower respiratory tract infection occurrence. In this review, we discuss animal and human studies suggesting a relationship between these two common conditions in mechanically ventilated patients and potential interventions that should be evaluated. Further large prospective studies in carefully selected groups of patients are required to confirm the potential role of hyperoxemia in VAP pathogenesis and to evaluate the impact of a conservative oxygen strategy vs. a conventional strategy on the incidence of VAP.

Heated humidified high-flow nasal cannula oxygen after thoracic surgery - A randomized prospective clinical pilot trial

BACKGROUND

Thoracic surgery patients are at high-risk for adverse pulmonary outcomes. Heated humidified high-flow nasal cannula oxygen (HHFNC O₂) may decrease such events. We hypothesized that patients randomized to prophylactic HHFNC O₂ would develop fewer pulmonary complications compared to conventional O₂ therapy.

METHODS AND PATIENTS

Fifty-one patients were randomized to HHFNC O₂ vs. conventional O₂. The primary outcome was a composite of postoperative pulmonary complications. Secondary outcomes included oxygenation and length of stay. Continuous variables were compared with t-test or Mann-Whitney-U test, categorical variables with Fisher's Exact test.

RESULTS

There were no differences in postoperative pulmonary complications based on intention to treat [two in HHFNC O₂ (n=25), two in control (n=26), p=0.680], and after exclusion of patients who discontinued HHFNC O₂ early [one in HHFNC O₂ (n=18), two in control (n=26), p=0.638]. Discomfort from HHFNC O₂ occurred in 11/25 (44%); 7/25 (28%) discontinued treatment.

CONCLUSIONS

Pulmonary complications were rare after thoracic surgery. Although HHFNC O₂ did not convey significant benefits, these results need to be interpreted with caution, as our study was likely underpowered to detect a reduction in pulmonary complications. High rates of patient-reported discomfort with HHFNC O₂ need to be considered in clinical practice and future trials.

Noninvasive ventilation versus oxygen therapy for the treatment of acute respiratory failure

INTRODUCTION

There is an ongoing discussion on whether oxygen therapy or noninvasive ventilation (NIV) should be used in patient with acute respiratory failure. While respiratory acidosis, especially in case of COPD exacerbation, is a clear indication for NIV, data available in patients with acute hypoxemic respiratory failure (AHRF) are ambiguous. In addition, recently the use of nasal high flow (NHF) has been increased. Despite that NHF has been studied as an alternative to NIV, the clinical advantages of NHF need to be confirmed.

AREAS COVERED

The purpose of this review is to enhance our understanding about the management of AHRF in specific settings, focusing on recent papers in which NIV and standard oxygen or NHF have been compared. Expert commentary: The choice of the most appropriate strategy for AHRF treatment should be made based upon patient's clinical status, underlying diseases, level of required respiratory support and patient's tolerance and comfort.

The optimum timing to wean invasive ventilation for patients with AECOPD or COPD with pulmonary infection

COPD is characterized by a progressive decline in lung function and mental and physical comorbidities. It is a significant burden worldwide due to its growing prevalence, comorbidities, and mortality. Complication by bronchial-pulmonary infection causes 50%-90% of acute exacerbations of COPD (AECOPD), which may lead to the aggregation of COPD symptoms and the development of acute respiratory failure. Non-invasive or invasive ventilation (IV) is usually implemented to treat acute respiratory failure. However, ventilatory support (mainly IV) should be discarded as soon as possible to prevent the onset of time-dependent complications. To withdraw IV, an optimum timing has to be selected based on weaning assessment and spontaneous breathing trial or replacement of IV by non-IV at pulmonary infection control window. The former method is more suitable for patients with AECOPD without significant bronchial-pulmonary infection while the latter method is more suitable for patients with AECOPD with acute significant bronchial-pulmonary infection.

Patient-controlled Analgesia with Target-controlled Infusion of Hydromorphone in Postoperative Pain Therapy

Background

Patient-controlled analgesia (PCA) is a common method for postoperative pain therapy, but it is characterized by large variation of plasma concentrations. PCA with target-controlled infusion (TCI-PCA) may be an alternative. In a previous analysis, the authors developed a pharmacokinetic model for hydromorphone. In this secondary analysis, the authors investigated the feasibility and efficacy of TCI-PCA for postoperative pain therapy with hydromorphone.

Methods

Fifty adult patients undergoing cardiac surgery were enrolled in this study. Postoperatively, hydromorphone was applied intravenously during three sequential periods: (1) as TCI with plasma target concentrations of 1 to 2 ng/ml until extubation; (2) as TCI-PCA with plasma target concentrations between 0.8 and 10 ng/ml during the following 6 to 8 h; and (3) thereafter as PCA with a bolus dose of 0.2 mg until the next morning. During TCI-PCA, pain was regularly assessed using the 11-point numerical rating scale (NRS). A pharmacokinetic/pharmacodynamic model was developed using ordinal logistic regression based on measured plasma concentrations.

Results

Data of 43 patients aged 40 to 81 yr were analyzed. The hydromorphone dose during TCI-PCA was 0.26 mg/h (0.07 to 0.93 mg/h). The maximum plasma target concentration during TCI-PCA was 2.3 ng/ml (0.9 to 7.0 ng/ml). The NRS score under deep inspiration was less than 5 in 83% of the ratings. Nausea was present in 30%, vomiting in 9%, and respiratory insufficiency in 5% of the patients. The EC50 of hydromorphone for NRS of 4 or less was 4.1 ng/ml (0.6 to 12.8 ng/ml).

Conclusion

TCI-PCA with hydromorphone offered satisfactory postoperative pain therapy with moderate side effects.

Noninvasive ventilation practice patterns for acute respiratory failure in Canadian tertiary care centres: A descriptive analysis

BACKGROUND

The extent of noninvasive ventilation (NIV) use for patients with acute respiratory failure in Canadian hospitals, indications for use and associated outcomes are unknown.

OBJECTIVE

To describe NIV practice variation in the acute setting.

METHODS

A prospective observational study involving 11 Canadian tertiary care centres was performed. Data regarding NIV indication, mode and outcomes were collected for all adults (>16 years of age) treated with NIV for acute respiratory failure during a four-week period (between February and August 2011). Logistic regression with site as a random effect was used to examine the association between preselected predictors and mortality or intubation.

RESULTS

A total of 330 patients (mean [± SD] 30±12 per centre) were included. The most common indications for NIV initiation were pulmonary edema (104 [31.5%]) and chronic obstructive pulmonary disease (99 [30.0%]). Significant differences in indications for NIV use across sites, specialty of ordering physician and location of NIV initiation were noted. Although intubation rates were not statistically different among sites (range 10.3% to 45.4%), mortality varied significantly (range 6.7% to 54.5%; P=0.006). In multivariate analysis, the most significant independent predictor of avoiding intubation was do-not-resuscitate status (OR 0.11 [95% CI 0.03 to 0.37]).

CONCLUSION

Significant variability existed in NIV use and associated outcomes among Canadian tertiary care centres. Assignment of do-not-resuscitate status prevented intubation.

Continuous positive airway pressure (CPAP) during the postoperative period for prevention of postoperative morbidity and mortality following major abdominal surgery

BACKGROUND

Major abdominal surgery can be associated with a number of serious complications that may impair patient recovery. In particular, postoperative pulmonary complications (PPCs), including respiratory complications such as atelectasis and pneumonia, are a major contributor to postoperative morbidity and may even contribute to increased mortality. Continuous positive airway pressure (CPAP) is a type of therapy that uses a high-pressure gas source to deliver constant positive pressure to the airways throughout both inspiration and expiration. This approach is expected to prevent some pulmonary complications, thus reducing mortality.

OBJECTIVES

To determine whether any difference can be found in the rate of mortality and adverse events following major abdominal surgery in patients treated postoperatively with CPAP versus standard care, which may include traditional oxygen delivery systems, physiotherapy and incentive spirometry.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) 2013, Issue 9; Ovid MEDLINE (1966 to 15 September 2013); EMBASE (1988 to 15 September 2013); Web of Science (to September 2013) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (to September 2013).

SELECTION CRITERIA

We included all randomized controlled trials (RCTs) in which CPAP was compared with standard care for prevention of postoperative mortality and adverse events following major abdominal surgery. We included all adults (adults as defined by individual studies) of both sexes. The intervention of CPAP was applied during the postoperative period. We excluded studies in which participants had received PEEP during surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies that met the selection criteria from all studies identified by the search strategy. Two review authors extracted the data and assessed risk of bias separately, using a data extraction form. Data entry into RevMan was performed by one review author and was checked by another for accuracy. We performed a limited meta-analysis and constructed a summary of findings table.

MAIN RESULTS

We selected 10 studies for inclusion in the review from 5236 studies identified in the search. These 10 studies included a total of 709 participants. Risk of bias for the included studies was assessed as high in six studies and as unclear in four studies.Two RCTs reported all-cause mortality. Among 413 participants, there was no clear evidence of a difference in mortality between CPAP and control groups, and considerable heterogeneity between trials was noted (risk ratio (RR) 1.28, 95% confidence interval (CI) 0.35 to 4.66; I(2) = 75%).Six studies reported demonstrable atelectasis in the study population. A reduction in atelectasis was observed in the CPAP group, although heterogeneity between studies was substantial (RR 0.62, 95% CI 0.45 to 0.86; I(2) = 61%). Pneumonia was reported in five studies, including 563 participants; CPAP reduced the rate of pneumonia, and no important heterogeneity was noted (RR 0.43, 95% CI 0.21 to 0.84; I(2) = 0%). The number of participants identified as having serious hypoxia was reported in two studies, with no clear difference between CPAP and control groups, given imprecise results and substantial heterogeneity between trials (RR 0.48, 95% CI 0.22 to 1.02; I(2) = 67%). A reduced rate of reintubation was reported in the CPAP group compared with the control group in two studies, and no important heterogeneity was identified (RR 0.14, 95% CI 0.03 to 0.58; I(2) = 0%). Admission into the intensive care unit (ICU) for invasive ventilation and supportive care was reduced in the CPAP group, but this finding did not reach statistical significance (RR 0.45, 95% CI 0.18 to 1.14; I(2) = 0).Secondary outcomes such as length of hospital stay and adverse effects were only minimally reported.A summary of findings table was constructed using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) principle. The quality of evidence was determined to be very low.

AUTHORS' CONCLUSIONS

Very low-quality evidence from this review suggests that CPAP initiated during the postoperative period might reduce postoperative atelectasis, pneumonia and reintubation, but its effects on mortality, hypoxia or invasive ventilation are uncertain. Evidence is not sufficiently strong to confirm the benefits or harms of CPAP during the postoperative period in those undergoing major abdominal surgery. Most of the included studies did not report on adverse effects attributed to CPAP.New, high-quality research is much needed to evaluate the use of CPAP in preventing mortality and morbidity following major abdominal surgery. With increasing availability of CPAP to our surgical patients and its potential to improve outcomes (possibly in conjunction with intraoperative lung protective ventilation strategies), unanswered questions regarding its efficacy and safety need to be addressed. Any future study must report on the adverse effects of CPAP.

Early postoperative prophylactic noninvasive ventilation after major lung resection in COPD patients: a randomized controlled trial

OBJECTIVES

To investigate whether prophylactic postoperative NIV prevents respiratory complications following lung resection surgery in COPD patients.

METHODS

In seven thoracic surgery departments, 360 COPD patients undergoing lung resection surgery were randomly assigned to two groups: conventional postoperative treatment without (n = 179) or with (n = 181) prophylactic NIV, applied intermittently during 6 h per day for 48 h following surgery. The primary endpoint was the rate of acute respiratory events (ARE) at 30 days postoperatively (ITT analysis). Secondary endpoints were acute respiratory failure (ARF), intubation rate, mortality rate, infectious and non-infectious complications, and duration of ICU and hospital stay.

MEASUREMENTS AND MAIN RESULTS

ARE rates did not differ between the prophylactic NIV and control groups (57/181, 31.5 vs. 55/179, 30.7%, p = 0.93). ARF rate was 18.8% in the prophylactic NIV group and 24.5% in controls (p = 0.20). Re-intubation rates were similar in the prophylactic NIV and control group [10/181 (5.5%) and 13/179 (7.2%), respectively, p = 0.53]. Mortality rates were 5 and 2.2% in the control and prophylactic NIV groups, respectively (p = 0.16). Infectious and non-infectious complication rates, and duration of ICU and hospital stays were similar between groups.

CONCLUSIONS

Prophylactic postoperative NIV did not reduce the rate of ARE in COPD patients undergoing lung resection surgery and did not influence other postoperative complications rates, mortality rates, and duration of ICU and hospital stay.

[Esophageal cancer surgery: evolution of pain management, hemodynamics and ventilation practices during 16 years]

OBJECTIVE

To describe the evolution of perioperative anesthesia practices in for esophageal cancer surgery.

PATIENTS AND METHODS

We conducted an observational retrospective study in a single center evaluating main perioperative practices during 16 years (1994-2009). Statistical analysis was done on 4 chronologic quartiles of same sample size.

RESULTS

Two hundred and seven consecutive patients were included during the 4 periods 1994-1997 (n=52), 1997-1999 (n=52), 1999-2003 (n=52) and 2004-2009 (n=51). The main significant evolutions between the first and the fourth period were observed: (i) in ventilation: lower tidal volume (9.6[8.6-10.6] vs 7.6[7.0-8.3] mL/kg of ideal body weight (IBW), p<0.01), increased use of Positive End Expiratory Pressure (0 vs 83%, p<0.001) and increased use of post-operative non-invasive ventilation (0 vs 51%, p<0.001); (ii) in hemodynamic management: lower fluid replacement (20.6 [16.0-24.6] vs 12.6 [9.7-16.2] mL/h/kg of IBW, p<0.001); (iii) in analgesia: increased use of epidural thoracic anesthesia (31 vs 57%, p<0.001). Peroperative bleeding, type of fluid replacement, length of mechanical ventilation, length of stay in intensive care unit, ventilatory free days and mortality at day 28 didn't change.

CONCLUSIONS

During these previous years, anesthesia practices in ventilation, hemodynamics and analgesia for esophageal cancer surgery have changed.

Preadmission interventions to prevent postoperative complications in older cardiac surgery patients: a systematic review

OBJECTIVE(S)

The literature on postoperative complications in cardiac surgery patients shows high incidences of postoperative complications such as delirium, depression, pressure ulcer, infection, pulmonary complications and atrial fibrillation. These complications are associated with functional and cognitive decline and a decrease in the quality of life after discharge. Several studies attempted to prevent one or more postoperative complications by preoperative interventions. Here we provide a comprehensive overview of both single and multiple component preadmission interventions designed to prevent postoperative complications.

METHODS

We systematically reviewed the literature following the PRISMA statement guidelines.

RESULTS

Of 1335 initial citations, 31 were subjected to critical appraisal. Finally, 23 studies were included, of which we derived a list of interventions that can be applied in the preadmission period to effectively reduce postoperative depression, infection, pulmonary complications, atrial fibrillation, prolonged intensive care unit stay and hospital stay in older elective cardiac surgery patients. No high quality studies were found describing effective interventions to prevent postoperative delirium. We did not find studies specifically targeting the prevention of pressure ulcers in this patient population.

CONCLUSIONS

Multi-component approaches that include different single interventions have the strongest effect in preventing postoperative depression, pulmonary complications, prolonged intensive care unit stay and hospital stay. Postoperative infection can be best prevented by disinfection with chlorhexidine combined with immune-enhancing nutritional supplements. Atrial fibrillation might be prevented by ingestion of N-3 polyunsaturated fatty acids. High quality studies are urgently needed to evaluate preadmission preventive strategies to reduce postoperative delirium or pressure ulcers in older elective cardiac surgery patients.

Effect of adding postoperative noninvasive ventilation to usual care to prevent pulmonary complications in patients undergoing coronary artery bypass grafting: a randomized controlled trial

OBJECTIVE

We compared the efficacy of noninvasive ventilation with bilevel positive airway pressure added to usual care versus usual care alone in patients undergoing coronary artery bypass grafting.

METHODS

We performed a 2-group, parallel, randomized controlled trial. The primary outcome was time until fit for discharge. Secondary outcomes were partial pressure of carbon dioxide, forced expiratory volume in 1 second, atelectasis, adverse events, duration of intensive care stay, and actual postoperative stay.

RESULTS

A total of 129 patients were randomly allocated to bilevel positive airway pressure (66) or usual care (63). Three patients allocated to bilevel positive airway pressure withdrew. The median duration of bilevel positive airway pressure was 16 hours (interquartile range, 11-19). The median duration of hospital stay until fit for discharge was 5 days for the bilevel positive airway pressure group (interquartile range, 4-6) and 6 days for the usual care group (interquartile range, 5-7; hazard ratio, 1.68; 95% confidence interval, 1.08-2.31; P = .019). There was no significant difference in duration of intensive care, actual postoperative stay, and mean percentage of predicted forced expiratory volume in 1 second on day 3. Mean partial pressure of carbon dioxide was significantly reduced 1 hour after bilevel positive airway pressure application, but there was no overall difference between the groups up to 24 hours. Basal atelectasis occurred in 15 patients (24%) in the usual care group and 2 patients (3%) in the bilevel positive airway pressure group. Overall, 30% of patients in the bilevel positive airway pressure group experienced an adverse event compared with 59% in the usual care group.

CONCLUSIONS

Among patients undergoing elective coronary artery bypass grafting, the use of bilevel positive airway pressure at extubation reduced the recovery time. Supported by trained staff, more than 75% of all patients allocated to bilevel positive airway pressure tolerated it for more than 10 hours.

Diagnosis, prevention and management of postoperative pulmonary edema

Postoperative pulmonary edema is a well-known postoperative complication caused as a result of numerous etiological factors which can be easily detected by a careful surveillance during postoperative period. However, there are no preoperative and intraoperative criteria which can successfully establish the possibilities for development of postoperative pulmonary edema. The aims were to review the possible etiologic and diagnostic challenges in timely detection of postoperative pulmonary edema and to discuss the various management strategies for prevention of this postoperative complication so as to decrease morbidity and mortality. The various search engines for preparation of this manuscript were used which included Entrez (including Pubmed and Pubmed Central), NIH.gov, Medknow.com, Medscape.com, WebMD.com, Scopus, Science Direct, MedHelp.org, yahoo.com and google.com. Manual search was carried out and various text books and journals of anesthesia and critical care medicine were also searched. From the information gathered, it was observed that postoperative cardiogenic pulmonary edema in patients with serious cardiovascular diseases is most common followed by noncardiogenic pulmonary edema which can be due to fluid overload in the postoperative period or it can be negative pressure pulmonary edema (NPPE). NPPE is an important clinical entity in immediate post-extubation period and occurs due to acute upper airway obstruction and creation of acute negative intrathoracic pressure. NPPE carries a good prognosis if promptly diagnosed and appropriately treated with or without mechanical ventilation.

Difficult Airway Society Guidelines for the management of tracheal extubation

Tracheal extubation is a high-risk phase of anaesthesia. The majority of problems that occur during extubation and emergence are of a minor nature, but a small and significant number may result in injury or death. The need for a strategy incorporating extubation is mentioned in several international airway management guidelines, but the subject is not discussed in detail, and the emphasis has been on extubation of the patient with a difficult airway. The Difficult Airway Society has developed guidelines for the safe management of tracheal extubation in adult peri-operative practice. The guidelines discuss the problems arising during extubation and recovery and promote a strategic, stepwise approach to extubation. They emphasise the importance of planning and preparation, and include practical techniques for use in clinical practice and recommendations for post-extubation care.

Negative pressure pulmonary edema revisited: Pathophysiology and review of management

Negative pressure pulmonary edema (NPPE) is a dangerous and potentially fatal condition with a multifactorial pathogenesis. Frequently, NPPE is a manifestation of upper airway obstruction, the large negative intrathoracic pressure generated by forced inspiration against an obstructed airway is thought to be the principal mechanism involved. This negative pressure leads to an increase in pulmonary vascular volume and pulmonary capillary transmural pressure, creating a risk of disruption of the alveolar-capillary membrane. The early detection of the signs of this syndrome is vital to the treatment and to patient outcome. The purpose of this review is to highlight the available literature on NPPE, while probing the pathophysiological mechanisms relevant in both the development of this condition and that involved in its resolution.

Protocol for a randomised controlled trial of nasal high flow oxygen therapy compared to standard care in patients following cardiac surgery: the HOT-AS study

BACKGROUND

Postoperative respiratory complications following cardiac surgery may increase morbidity, mortality and length of stay. Non-invasive respiratory support therapies can be used prophylactically or curatively to reduce respiratory complications. One system, nasal high flow oxygen therapy, is in use in many intensive care units (ICUs) however there is a lack of information regarding its clinical utility and efficacy.

OBJECTIVES

This paper outlines the study protocol and methodology for a study designed to determine if the prophylactic use of nasal high flow oxygen therapy can improve pulmonary function in patients following cardiac surgery.

METHODS/DESIGN

A prospective randomised controlled trial will be conducted of adult patients scheduled for cardiac surgery and admitted to the Cardiothoracic Intensive Care Unit of a tertiary hospital. Study participants will be assigned to receive either nasal high flow or standard oxygen therapy (oxygen therapy at 2-4 L/min via either simple facemask or nasal cannulae) at extubation. The primary outcome measure is improved pulmonary function demonstrated by SpO2/FiO2 ratio >445 on post-operative day 3. Secondary outcome measures include atelectasis score on chest X-ray; spirometry; readmission to ICU for respiratory causes; ICU and hospital length of stay; mortality and incidence of respiratory complications at day 28; oxygenation variables; use of adjunctive respiratory support therapies; escalation of respiratory support; adverse events and patient comfort during administration of oxygen therapy.

SAMPLE SIZE

It was calculated that 340 patients will be required--170 per arm of study--to give a 90% power to detect a 15% treatment effect.

RESULTS

This study started recruiting in March 2011. It is anticipated that enrollment will be complete in April 2012 and results available towards the end of 2012.

CONCLUSION

This study will provide evidence of any benefits in the use of prophylactic nasal high flow therapy in post-operative cardiac surgical patients.

TRIAL REGISTRATION

This trial is registered with the Australian New Zealand Clinical Trials Registry www.anzctr.org.au (ACTRN12610000973011).

WITHDRAWN: Primary prevention for alcohol misuse in young people

BACKGROUND

Alcohol misuse is a cause of concern for health services, policy makers, prevention workers, the criminal justice system, youth workers, teachers and parents.

OBJECTIVES

1. To identify and summarize rigorous evaluations of psychosocial and educational interventions aimed at the primary prevention of alcohol misuse by young people. 2. To assess the effectiveness of primary prevention interventions over the longer-term (> 3 years).

SEARCH STRATEGY

Databases searched (no time limits): Project CORK, BIDS, PSYCLIT, ERIC, ASSIA, MEDLINE, FAMILY-RESOURCES-DATABASE, HEALTH-PERIODICALS-DATABASE, EMBASE, BIDS, Dissertation-Abstracts, SIGLE, DRUG-INFO, SOMED, Social-Work-Abstracts, National-Clearinghouse-on-Alcohol-and-Drug-Information, Mental-Health-Abstracts, DRUG-database, ETOH (all searched Feb-June 2002).

SELECTION CRITERIA

1. randomised controlled and non-randomised controlled and interrupted time series designs. 2. educational and psychosocial primary prevention interventions for young people up to 25 years old. 3. alcohol-specific or generic (drugs; lifestyle) interventions providing alcohol outcomes reported. 4. alcohol outcomes: alcohol use, age of alcohol initiation, drinking 5+ drinks on any one occasion, drunkeness, alcohol related violence, alcohol related crime, alcohol related risky behaviour.

DATA COLLECTION AND ANALYSIS

Stage 1: All papers screened by one reviewer against inclusion criteria. Stage 2: For those papers that passed Stage 1, key information was extracted from each paper by 2-3 reviewers.

MAIN RESULTS

20 of the 56 studies included showed evidence of ineffectiveness. No firm conclusions about the effectiveness of prevention interventions in the short- and medium-term were possible. Over the longer-term, the Strengthening Families Program (SFP) showed promise as an effective prevention intervention. The Number Needed to Treat (NNT) for the SFP over 4 years for three alcohol initiation behaviours (alcohol use, alcohol use without permission and first drunkeness) was 9 (for all three behaviours). One study also highlighted the potential value of culturally focused skills training over the longer-term (NNT=17 over three-and-a-half years for 4+ drinks in the last week).

AUTHORS' CONCLUSIONS

1. Research into important outcome variables needs to be undertaken. 2. Methodology of evaluations needs to be improved. 3. The Strengthening Families Programme needs to be evaluated on a larger scale and in different settings. 4. Culturally-focused interventions require further development and rigorous evaluation. 5. An international register of alcohol and drug misuse prevention interventions should be established and criteria agreed for rating prevention intervention in terms of safety, efficacy and effectiveness.