Airway Closure during Surgical Pneumoperitoneum in Obese Patients.

BACKGROUND: Airway closure causes lack of communication between proximal airways and alveoli, making tidal inflation start only after a critical airway opening pressure is overcome. The authors conducted a matched cohort study to report the existence of this phenomenon among obese patients undergoing general anesthesia. METHODS: Within the procedures of a clinical trial during gynecological surgery, obese patients underwent respiratory/lung mechanics and lung volume assessment both before and after pneumoperitoneum, in the supine and Trendelenburg positions, respectively. Among patients included in this study, those exhibiting airway closure were compared to a control group of subjects enrolled in the same trial and matched in 1:1 ratio according to body mass index. RESULTS: Eleven of 50 patients (22%) showed airway closure after intubation, with a median (interquartile range) airway opening pressure of 9 cm H2O (6 to 12). With pneumoperitoneum, airway opening pressure increased up to 21 cm H2O (19 to 28) and end-expiratory lung volume remained unchanged (1,294 ml [1,154 to 1,363] vs. 1,160 ml [1,118 to 1,256], P = 0.155), because end-expiratory alveolar pressure increased consistently with airway opening pressure and counterbalanced pneumoperitoneum-induced increases in end-expiratory esophageal pressure (16 cm H2O [15 to 19] vs. 27 cm H2O [23 to 30], P = 0.005). Conversely, matched control subjects experienced a statistically significant greater reduction in end-expiratory lung volume due to pneumoperitoneum (1,113 ml [1,040 to 1,577] vs. 1,000 ml [821 to 1,061], P = 0.006). With airway closure, static/dynamic mechanics failed to measure actual lung/respiratory mechanics. When patients with airway closure underwent pressure-controlled ventilation, no tidal volume was inflated until inspiratory pressure overcame airway opening pressure. CONCLUSIONS: In obese patients, complete airway closure is frequent during anesthesia and is worsened by Trendelenburg pneumoperitoneum, which increases airway opening pressure and alveolar pressure: besides preventing alveolar derecruitment, this yields misinterpretation of respiratory mechanics and generates a pressure threshold to inflate the lung that can reach high values, spreading concerns on the safety of pressure-controlled modes in this setting.

Prognostication in comatose survivors of cardiac arrest: an advisory statement from the European Resuscitation Council and the European Society of Intensive Care Medicine.

OBJECTIVES: To review and update the evidence on predictors of poor outcome (death, persistent vegetative state or severe neurological disability) in adult comatose survivors of cardiac arrest, either treated or not treated with controlled temperature, to identify knowledge gaps and to suggest a reliable prognostication strategy. METHODS: GRADE-based systematic review followed by expert consensus achieved using Web-based Delphi methodology, conference calls and face-to-face meetings. Predictors based on clinical examination, electrophysiology, biomarkers and imaging were included. RESULTS AND CONCLUSIONS: Evidence from a total of 73 studies was reviewed. The quality of evidence was low or very low for almost all studies. In patients who are comatose with absent or extensor motor response at ≥72 h from arrest, either treated or not treated with controlled temperature, bilateral absence of either pupillary and corneal reflexes or N20 wave of short-latency somatosensory evoked potentials were identified as the most robust predictors. Early status myoclonus, elevated values of neuron specific enolase at 48 72 h from arrest, unreactive malignant EEG patterns after rewarming, and presence of diffuse signs of postanoxic injury on either computed tomography or magnetic resonance imaging were identified as useful but less robust predictors. Prolonged observation and repeated assessments should be considered when results of initial assessment are inconclusive. Although no specific combination of predictors is sufficiently supported by available evidence, a multimodal prognostication approach is recommended in all patients.

Prognostication in comatose survivors of cardiac arrest: an advisory statement from the European Resuscitation Council and the European Society of Intensive Care Medicine.

OBJECTIVES: To review and update the evidence on predictors of poor outcome (death, persistent vegetative state or severe neurological disability) in adult comatose survivors of cardiac arrest, either treated or not treated with controlled temperature, to identify knowledge gaps and to suggest a reliable prognostication strategy. METHODS: GRADE-based systematic review followed by expert consensus achieved using Web-based Delphi methodology, conference calls and face-to-face meetings. Predictors based on clinical examination, electrophysiology, biomarkers and imaging were included. RESULTS AND CONCLUSIONS: Evidence from a total of 73 studies was reviewed. The quality of evidence was low or very low for almost all studies. In patients who are comatose with absent or extensor motor response at ≥ 72 h from arrest, either treated or not treated with controlled temperature, bilateral absence of either pupillary and corneal reflexes or N20 wave of short-latency somatosensory evoked potentials were identified as the most robust predictors. Early status myoclonus, elevated values of neuron-specific enolase at 48-72 h from arrest, unreactive malignant EEG patterns after rewarming, and presence of diffuse signs of postanoxic injury on either computed tomography or magnetic resonance imaging were identified as useful but less robust predictors. Prolonged observation and repeated assessments should be considered when results of initial assessment are inconclusive. Although no specific combination of predictors is sufficiently supported by available evidence, a multimodal prognostication approach is recommended in all patients.

Rapidly fatal hemorrhagic pneumonia and group A Streptococcus serotype M1.

We report 3 cases of fulminant hemorrhagic pneumonia in previously health patients. Sudden-onset hemoptysis and dyspnea developed; all 3 patients and died <12 h later of massive pulmonary bleeding, despite aggressive supportive care. Postmortem analysis showed that the illnesses were caused by group A Streptococcus emm1/sequence type 28 strains.

Predictors of poor neurological outcome in adult comatose survivors of cardiac arrest: a systematic review and meta-analysis. Part 2: Patients treated with therapeutic hypothermia.

AIMS AND METHODS: To systematically review the accuracy of early (≤7 days) predictors of poor outcome, defined as death or vegetative state (Cerebral Performance Categories [CPC] 4-5) or death, vegetative state or severe disability (CPC 3-5), in comatose adult survivors from cardiac arrest (CA) treated using therapeutic hypothermia (TH). Electronic databases were searched for eligible studies. Sensitivity, specificity, and false positive rates (FPR) for each predictor were calculated. Quality of evidence (QOE) was evaluated according to the GRADE guidelines. RESULTS: 37 studies (2403 patients) were included. A bilaterally absent N20 SSEP wave during TH (4 studies; QOE: Moderate) or after rewarming (5 studies; QOE: Low), a nonreactive EEG background (3 studies; QOE: Low) after rewarming, a combination of absent pupillary light and corneal reflexes plus a motor response no better than extension (M≤2) (1 study; QOE: Very low) after rewarming predicted CPC 3-5 with 0% FPR and narrow (<10%) 95% confidence intervals. No consistent threshold for 0% FPR could be identified for blood levels of biomarkers. In 6/8 studies on SSEP, in 1/3 studies on EEG reactivity and in the single study on clinical examination the investigated predictor was used for decisions to withdraw treatment, causing the risk of a self-fulfilling prophecy. CONCLUSIONS: in the first 7 days after CA, a bilaterally absent N20 SSEP wave anytime, a nonreactive EEG after rewarming or a combination of absent ocular reflexes and M≤2 after rewarming predicted CPC 3-5 with 0% FPR and narrow 95% CIs, but with a high risk of bias.

Predictors of poor neurological outcome in adult comatose survivors of cardiac arrest: a systematic review and meta-analysis. Part 1: patients not treated with therapeutic hypothermia.

AIMS AND METHODS: To systematically review the accuracy of early (≤7 days) predictors of poor outcome defined as death or vegetative state (Cerebral Performance Categories [CPC] 4-5) or death, vegetative state or severe disability (CPC 3-5) in comatose survivors from cardiac arrest not treated using therapeutic hypothermia (TH). PubMed, Scopus and the Cochrane Database of Systematic reviews were searched for eligible studies. Sensitivity, specificity, false positive rates (FPR) for each predictor were calculated and results of predictors with similar time points and outcome definitions were pooled. Quality of evidence (QOE) was evaluated according to the GRADE guidelines. RESULTS: 50 studies (2828 patients) were included in final analysis. Presence of myoclonus at 24-48h, bilateral absence of short-latency somatosensory evoked potential (SSEP) N20 wave at 24-72h, absence of electroencephalographic activity >20-21µV ≤72h and absence of pupillary reflex at 72h predicted CPC 4-5 with 0% FPR and narrow (<10%) 95% confidence intervals. Absence of SSEP N20 wave at 24h predicted CPC 3-5 with 0% [0-8] FPR. Serum thresholds for 0% FPR of biomarkers neuron specific enolase (NSE) and S-100B were highly inconsistent among studies. Most of the studies had a low or very low QOE and did not report blinding of the treating team from the results of the investigated predictor. CONCLUSIONS: In comatose resuscitated patients not treated with TH presence of myoclonus, absence of pupillary reflex, bilateral absence of N20 SSEP wave and low EEG voltage each predicted poor outcome early and accurately, but with a relevant risk of bias.

Accuracy of plethysmographic indices as predictors of fluid responsiveness in mechanically ventilated adults: a systematic review and meta-analysis.

PURPOSE: To systematically review the accuracy of the variation in pulse oxymetry plethysmographic waveform amplitude (∆POP) and the Pleth Variability Index (PVI) as predictors of fluid responsiveness in mechanically ventilated adults. METHODS: MEDLINE, Scopus and the Cochrane Database of Systematic Reviews were screened for clinical studies in which the accuracy of ∆POP/PVI in predicting the hemodynamic response to a subsequent fluid bolus had been investigated. Random-effects meta-analysis was used to summarize the results. Data were stratified according to the amount of fluid bolus (large vs. small) and to the study index (∆POP vs. PVI). RESULTS: Ten studies in 233 patients were included in this meta-analysis. All patients were in normal sinus rhythm. The pooled area under the receiver operating characteristic curve (AUC) for identification of fluid responders was 0.85 [95 % confidence interval (CI) 0.79-0.92]. Pooled sensitivity and specificity were 0.80 (95 % CI 0.74-0.85) and 0.76 (0.68-0.82), respectively. No heterogeneity was found within studies with the same amount of fluid bolus, nor between studies on ∆POP and those on PVI. The AUC was significantly larger in studies with a large bolus amount than in those with a small bolus [0.92 (95 % CI 0.87-0.96) vs. 0.70 (0.62-0.79); p < 0.0001]. Sensitivity and specificity were also higher in studies with a large bolus [0.84 (95 % CI 0.77-0.90) vs. 0.72 (0.60-0.82) (small bolus), p = 0.08 and 0.86 (95 % CI 0.75-0.93) vs. 0.68 (0.56-0.77) (small bolus), p = 0.02], respectively. CONCLUSIONS: Based on our meta-analysis, we conclude that ∆POP and PVI are equally effective for predicting fluid responsiveness in ventilated adult patients in sinus rhythm. Prediction is more accurate when a large fluid bolus is administered.

Are patients brain-dead after successful resuscitation from cardiac arrest suitable as organ donors? A systematic review.

AIM: To compare the outcome of organs retrieved from patients brain dead due to cardiac arrest (CA) with that of organs retrieved from patients brain dead due to other causes (non-CA). METHODS: Systematic review. Clinical studies comparing the outcome of patients and organs retrieved from donors brain dead after being resuscitated from cardiac arrest with that of patients and organs retrieved from donors brain dead not due to cardiac arrest were considered for inclusion. Full-text articles were searched on MEDLINE, EmBASE, Cochrane Register of Controlled Trials and Cochrane Register of Systematic Reviews. MAIN OUTCOME MEASURE: One-year patient or organ survival rate. RESULTS: Four studies fulfilling inclusion criteria were found and three had sufficient quality to be included in final analysis. A total of 858 organs were transplanted from 741 donors. Since the transplanted organs (heart, liver, kidney, lung and intestine) were different in the three studies, metanalysis was not performed. There were no significant differences in 1-year survival rates between CA and non-CA groups. No significant differences were reported for 5-year survival rates, early recovery of transplanted organ function, and organ rejection rates. CONCLUSION: Survival rates of kidneys, livers, hearts and intestines retrieved from CA donors were not significantly different from that of organs transplanted from non-CA donors. Patients brain dead after having been resuscitated from cardiac arrest can be considered as potential donors for organ transplantation.

Which factors predict candidate outcome in advanced life support courses? A preliminary observational study.

PURPOSE: To identify factors associated with candidate outcome in the European Resuscitation Council (ERC) advanced life support (ALS) provider courses. METHODS: Medical doctors participating as candidates to consecutive ALS courses organised by an ERC training centre in Italy were enrolled in this prospective cohort study. The association between the ALS course outcome and candidate demographics, professional background and pre-course knowledge measured by using the pre-course multiple choice quiz (MCQ) was investigated by using logistic regression. RESULTS: A total of 283 candidates, median age 31 years, were evaluated. Among them, 269 (95.1%) passed the final evaluation and 14 (4.9%) failed. Candidates who passed were younger (median age 31 vs. 37.5 years; p = 0.006) and attained a higher pre-course MCQ score (median 84 vs. 72.5%; p < 0.0001). On multivariate analysis, a higher pre-course MCQ score (OR 1.18 [95%CI 1.09-1.28]) and a basic life support (BLS) certification (OR 5.00 [95%CI 1.12-22.42]) were independent predictors of candidate success, while older age was associated with a significantly higher risk of failing (OR 0.90 [95%CI 0.83-0.97]). Female candidates had higher pass rates (97.2 vs. 91.2%; p = 0.048); however, after correction for confounders gender was not significantly associated with candidate outcome. Neither candidate specialty nor site of work was a predictor of candidate success. CONCLUSIONS: On ALS courses, younger age and a higher level of specific pre-course knowledge, as measured by both the pre-course MCQ and the presence of BLS certification, are the most important predictors of success. Candidate gender and professional background did not show a significant correlation with course outcome.

Diagnostic accuracy of passive leg raising for prediction of fluid responsiveness in adults: systematic review and meta-analysis of clinical studies.

PURPOSE: To systematically review the published evidence on the ability of passive leg raising-induced changes in cardiac output (PLR-cCO) and in arterial pulse pressure (PLR-cPP) to predict fluid responsiveness. METHODS: MEDLINE, EMBASE and the Cochrane Database of Systematic Reviews were screened. Clinical trials on human adults published as full-text articles in indexed journals were included. Two authors independently used a standardized form to extract data about study characteristics and results. Study quality was assessed by using the QUADAS scale. RESULTS: Nine articles including a total of 353 patients were included in the final analysis. Data are reported as point estimate (95% confidence intervals). The pooled sensitivity and specificity of PLR-cCO were 89.4% (84.1-93.4%) and 91.4% (85.9-95.2%) respectively. Diagnostic odds ratio was 89.0 (40.2-197.3). The pooled area under the receiver operating characteristics curve (AUC) was 0.95 (0.92-0.97). The pooled correlation coefficient r between baseline value of PLR-cCO and CO increase after fluid load was 0.81 (0.75-0.86). The pooled difference in mean PLR-cCO values between responders and non-responders was 17.7% (13.6-21.8%). No significant differences were identified between patients adapted to ventilator versus those with inspiratory efforts nor between patients in sinus rhythm versus those with arrhythmias. The pooled AUC for PLR-cPP was 0.76 (0.67-0.86) and was significantly lower than the AUC for PLR-cCO (p < 0.001). The pooled difference in mean PLR-cPP values between responders and non-responders was 10.3% (6.5-14.1%). CONCLUSIONS: Passive leg raising-induced changes in cardiac output can reliably predict fluid responsiveness regardless of ventilation mode and cardiac rhythm. PLR-cCO has a significantly higher predictive value than PLR-cPP.

Nonthyroidal illness syndrome and prolonged mechanical ventilation in patients admitted to the ICU.

BACKGROUND: The effect of the nonthyroidal illness syndrome (NTIS) on the duration of mechanical ventilation (MV) has not been extensively investigated. This study aims to determine whether the NTIS is associated with the duration of MV in patients admitted to the ICU. METHODS: We evaluated all patients admitted over a 6-year period to our ICU who underwent invasive MV and had measurement of serum free triiodothyronine (fT3), free thyroxine (fT4), and thyroid-stimulating hormone (TSH) performed in the first 4 days after ICU admission and, subsequently, at least every 8 days during the time they received MV. The primary outcome measure was prolonged MV (PMV), which was defined as dependence on MV for > 13 days. RESULTS: Two hundred sixty-four patients were included. Fifty-six patients (normal-hormone group) had normal thyroid function test results, whereas 208 patients (low-fT3 group) had, at least in one hormone dosage, low levels of fT3 with normal (n = 145)/low (n = 63) levels of fT4 and normal (n = 189)/low (n = 19) levels of TSH. Patients in the low-fT3 group showed significantly higher mortality and simplified acute physiology score II, and significantly longer duration of MV and ICU length of stay compared with the normal-hormone group. Two of the variables studied were associated with PMV, as follows: the NTIS (odds ratio [OR], 2.25; 95% confidence interval [CI], 1.18 to 4.29; p = 0.01); and the presence of pneumonia (OR, 1.17; 95% CI, 1.06 to 3.01; p = 0.03). CONCLUSION: The NTIS represents a risk factor for PMV in mechanically ventilated, critically ill patients.

In-hospital cardiac arrest: incidence, prognosis and possible measures to improve survival.

DESIGN: Review. OBJECTIVE: Medical literature on in-hospital cardiac arrest (IHCA) was reviewed to summarise: (a) the incidence of and survival after IHCA, (b) major prognostic factors, (c) possible interventions to improve survival. RESULTS AND CONCLUSIONS: The incidence of IHCA is rarely reported in the literature. Values range between 1 and 5 events per 1,000 hospital admissions, or 0.175 events/bed annually. Reported survival to hospital discharge varies from 0% to 42%, the most common range being between 15% and 20%. Pre-arrest prognostic factors: the prognostic value of age is controversial. Among comorbidities, sepsis, cancer, renal failure and homebound lifestyle are significantly associated with poor survival. However, pre-arrest morbidity scores have not yet been prospectively validated as instruments to predict failure to survive after IHCA. Intra-arrest factors: ventricular fibrillation/ventricular tachycardia (VF/VT) as the first recorded rhythm and a shorter interval between IHCA and cardiopulmonary resuscitation or defibrillation are associated with higher survival. However, VF/VT is present in only 25-35% of IHCAs. Short-term survival is also higher in patients resuscitated with chest compression rates above 80/min. Interventions likely to improve survival include: early recognition and stabilisation of patients at risk of IHCA to enable prevention, faster and better in-hospital resuscitation and early defibrillation. Mild therapeutic hypothermia is effective as post-arrest treatment of out-of-hospital cardiac arrest due to VF/VT, but its benefit after IHCA and after cardiac arrest with non-VF/VT rhythms has not been clearly demonstrated.

Haemodynamic effects of mental stress during cardiac arrest simulation testing on advanced life support courses.

UNLABELLED: We investigated the haemodynamic response to the mental stress induced by being evaluated as a team leader in simulated advanced life support (ALS) scenarios. METHODS: Healthcare providers participating as candidates to ALS courses were monitored while acting as team leaders in a cardiac arrest testing scenario (CASTest). Heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured before, during and after the CASTest. The correlation between the haemodynamic responses and sex, age, body mass index (BMI) and marks on course multiple choice questions (MCQs) were studied using multiple linear regression. RESULTS: Eighty-eight subjects (46 women, 42 men, mean age 34.9+/-6.8 years) were enrolled. Mean HR, SBP and DBP increased significantly during the CASTest and reached a peak after a phase of the scenario which included an unsuccessful defibrillation. Ten minutes after the CASTest, HR, SBP and DBP were still significantly higher than their respective baseline values. A significant positive correlation was found between the DBP and SBP response during the scenario and the BMI, and between the DBP response and the candidates' age. The haemodynamic stress response was neither correlated with the candidates' marks in the course MCQ nor with their instructor potential (IP). CONCLUSION: During the testing scenario the ALS candidates showed a significant haemodynamic response to mental stress, which depended mainly on their age and BMI rather than on their knowledge and skills.

Automated external defibrillation by untrained deaf lay rescuers.

INTRODUCTION: The use of automated external defibrillators (AEDs) by lay rescuers can reduce the time to defibrillation, improving survival after out-of-hospital cardiac arrest. However, some people have hearing defects that can prevent them from understanding the AED verbal prompts. Moreover, even rescuers with normal hearing function may not easily understand the AED verbal prompts when operating in a noisy environment. This study was designed to assess the capability of rescuers to defibrillate effectively using an AED which included visual prompts. METHODS AND RESULTS: Nine deaf employees with no previous experience in basic life support (BLS) or defibrillation were asked to defibrillate a manikin following the text prompts of a Heartstart FR2+ AED. Subjects were tested before and after a 6 h BLS-AED course carried out with the help of a sign language interpreter. Before training, seven out of nine deaf subjects (78%) were able to defibrillate, eight out of nine subjects (89%) placed the pads correctly, and the mean time to defibrillation was 101.3 +/- 28.4 s. After the course, all subjects were able to complete the defibrillation sequence and place the pads correctly. The mean post-course time to defibrillation was 47.8 +/- 5.4 s (P < 0.001). None of the nine subjects touched the manikin during charging of the defibrillator and shock delivery before or after the course. CONCLUSIONS: This study demonstrates that untrained deaf rescuers can use AEDs appropriately providing that the defibrillator has visual instructions. Training improves defibrillator use and reduces time to defibrillation.

In-hospital cardiac arrest: survival depends mainly on the effectiveness of the emergency response.

OBJECTIVES: To evaluate the factors affecting the outcome of in-hospital cardiac arrest. SETTING: A 1400-bed tertiary care teaching hospital with a dedicated cardiac arrest team (CAT). The CAT was immediately available in monitored areas (intensive care unit and emergency room). In the wards the staff had only BLS skills and automated external defibrillation was not available. METHODS: A 2-year prospective audit according to the Utstein style. RESULTS: A total of 114 cardiac arrests (37 with VF/VT and 77 with non-VF/VT) were included. Fifty-two cardiac arrests (46%) occurred in monitored areas, 62 (54%) occurred in non-monitored areas. The CAT arrival time in non-monitored areas was 3.98+/-1.73 min. Thirty-seven patients (32%) survived to hospital discharge. Cardiac arrests occurring in monitored areas had a significantly better outcome than those occurring in the wards. Patient survival in the wards was significantly higher when the CAT arrival time was less than 3 min. No patient whose CAT arrival time was longer than 6 min survived. CAT arrival time was significantly shorter (1.30+/-1.70) in survivors than in non-survivors (2.51+/-2.37; P<0.005). Sex, age and presence of bystanders were not significantly associated with survival. CONCLUSIONS: In our setting, where bystander defibrillation was not available, the survival of patients having cardiac arrest in non-monitored areas strongly depends on advanced life support provided by the CAT. A faster CAT response and early defibrillation from the ward staff are the most important improvements necessary to increase cardiac arrest survival in our setting.