Francesco Zarantonello

Perioperative noninvasive ventilation in obese patients: a qualitative review and meta-analysis

BACKGROUND Perioperative noninvasive ventilation (NIV) has been proposed to reduce postoperative morbidity and improve perioperative outcomes in patients undergoing general anesthesia. Whether it is advantageous to apply NIV just before and after general anesthesia in obese patients has not been yet established. OBJECTIVES To perform a qualitative review and meta-analysis to assess the effectiveness and tolerability of perioperative NIV in obese patients. METHODS All studies in English language performed in clinical setting that compared the application of NIV with standard care just before and after induction of general anesthesia in obese adults (body mass index [BMI]≥35 kg/m(2)) were included. Data on oxygenation, respiratory function, complications, and outcomes were extracted. RESULTS Twenty-nine articles were selected and used in the qualitative review. Eleven studies including 768 patients were used for subsequent meta-analyses. Compared with standard preoxygenation, NIV was associated with a significant improvement in oxygenation (P<.0001) before tracheal intubation. Benefits in oxygenation (P<.0001), clearance of carbon dioxide (P<.0001), and pulmonary function testing (P<.0001) after general anesthesia were observed with NIV compared with standard care. Postoperatively, NIV was associated with a decreased risk of respiratory complications (relative risk [RR] = .33; 95% confidence interval [CI] .16-.66; P = .002), but not of reintubation after tracheal extubation (RR = .41; 95% CI .09-1.82]; P = .3657) and unplanned intensive care unit admission (RR = .43; 95% CI .16-1.15; P = .0937). NIV-related complications in obese patients were mainly due to intolerance and ranged from 7% to 28% of cases. NIV-related anastomotic leakage and adverse events were not reported. CONCLUSIONS Results from this review and meta-analysis suggest that NIV is well tolerated and effective in improving perioperative care in obese patients. The application of NIV before and after general anesthesia should be considered and promoted in relevant cases.

Sugammadex for reversal of neuromuscular blockade: a retrospective analysis of clinical outcomes and cost-effectiveness in a single center.

Objective The aim of the study is to evaluate the clinical and economic impact of introducing a rocuronium–neostigmine–sugammadex strategy into a cisatracurium–neostigmine regimen for neuromuscular block (NMB) management. Methods We conducted a retrospective analysis of clinical outcomes and cost-effectiveness in five operating rooms at University Hospital of Padova. A clinical outcome evaluation after sugammadex administration as first-choice reversal drug in selected patients (rocuronium–sugammadex) and as rescue therapy after neostigmine reversal (rocuronium–neostigmine–sugammadex) compared to control was performed. A cost-analysis of NMB management accompanying the introduction of a rocuronium–neostigmine–sugammadex strategy into a cisatracurium–neostigmine regimen was carried out. To such purpose, two periods were compared: 2011–2012, without sugammadex available; 2013–2014, with sugammadex available. A subsequent analysis was performed to evaluate if sugammadex replacing neostigmine as first choice reversal drug is cost-effective. Results The introduction of a rocuronium–neostigmine–sugammadex strategy into a cisatracurium–neostigmine regimen reduced the average cost of NMB management by 36%, from €20.8/case to €13.3/case. Patients receiving sugammadex as a first-choice reversal drug (3%) exhibited significantly better train-of-four ratios at extubation (P<0.001) and were discharged to the surgical ward (P<0.001) more rapidly than controls. The cost-saving of sugammadex as first-choice reversal drug has been estimated to be €2.9/case. Patients receiving sugammadex as rescue therapy after neostigmine reversal (3.2%) showed no difference in time to discharge to the surgical ward (P=0.44) compared to controls. No unplanned intensive care unit (ICU) admissions with rocuronium–neostigmine–sugammadex strategy were observed. The potential economic benefit in avoiding postoperative residual curarization (PORC)-related ICU admission in the 2013–2014 period was estimated at an average value of €13,548 (€9,316–€23,845). Conclusion Sugammadex eliminated PORC and associated morbidities. In our center, sugammadex reduced the costs of NMB management and promoted rapid turnover of patients in operating rooms, with total cost-effectiveness that counteracts the disadvantages of its high cost.

Predicting Noninvasive Ventilation Failure: Simplifying Is Not Always Easy.

e772 www.ccmjournal.org August 2016 • Volume 44 • Number 8 The authors reply: We thank Zarantonello and Esquinas (1) for their interest in our article reporting that a high tidal volume is associated with noninvasive ventilation (NIV) failure in patients receiving NIV for de novo acute hypoxemic respiratory distress (2). Zarantonello and Esquinas (1) point out that pneumonia was the cause of respiratory failure in 51 (82%) of patients included in our cohort. They reasonably assume that the efficacy of antimicrobial therapy might impact the NIV outcome and influence our results. We reviewed microbiologic documentation and antimicrobial therapy for each of the 51 patients with pneumonia, among whom 26 (51%) failed NIV. Twenty-nine patients with pneumonia (57%) were community-acquired and 22 (43%) associated with healthcare. The pulmonary infection was documented in 34 patients (67%), including 14 of 25 patients (56%) with NIV success and 20 of 26 patients (77%) with NIV failure, p value equal to 0.11; these results are consistent with previous reports (3). When empirical, the first line of antimicrobial therapy in our unit follows current recommendations (4). Based on the microbiologic documentation, the antimicrobial therapy received the first day of NIV treatment was deemed ineffective in only two patients who failed (8%) and no patient who succeeded NIV; p value equal to 0.16. In the 51 patients with pneumonia, we reassessed in our backward stepwise Cox proportional hazards regression model the four risk factors for NIV failure identified by univariable analysis (immunosuppression, Simplified Acute Physiology Score [SAPS] II at admission, Pao 2 -to-Fio 2 ratio before the onset of NIV treatment, and mean expired tidal volume [Vte] during NIV) along with the efficacy of initial antimicrobial therapy. The mean Vte (in mL/kg of predicted body weight) remained independently associated with NIV failure (adjusted Hazard Ratio [95% CI], 1.261 [1.012–1.572]; p = 0.04), along with the SAPS II (adjusted Hazard Ratio [95% CI], 1.057 [1.017–1.098]; p = 0.004). Our results do not support a key role for antimicrobial efficacy in altering NIV outcome in our cohort. The authors have disclosed that they do not have any potential conflicts of interest.

Preoxygenation Before Intubation in the Critically Ill Obese Patient

Critically ill obese patients are at increased risk of severe hypoxemia during intubation. Preoxygenation consists in enhancing the patient’s oxygen reserve to avoid this complication and should be routinely applied in clinical practice. Correctly positioning the patient or using specific techniques might provide additional time before hypoxemia develops.

Obesity and perioperative noninvasive ventilation in bariatric surgery

The incidence and prevalence of obesity continues to increase globally. Physicians will therefore provide care for an increasing number of obese patients in their clinical practice. Optimal management of these patients is required to minimize the risk of perioperative complications that increase morbidity and mortality. Obesity affects the respiratory function. It is generally associated with reduced lung volume with increased atelectasis, decreased lung and chest wall compliance, increased airway resistance, and moderate to severe hypoxemia. These physiologic alterations are generally more pronounced in obesity complicated by obstructive sleep apnea syndrome or obesity hypoventilation syndrome. Anesthesia and surgery can profoundly impair respiratory function, increasing the risk of postoperative respiratory complications and acute respiratory failure. Certain comorbidities associated with obesity (e.g., metabolic syndrome, obstructive sleep apnea, pulmonary disease) further increase the risk of perioperative complications. Non-invasive ventilation (NIV) is emerging as an important strategy to minimize perioperative complications. It may ameliorate obesity-related comorbidities, counteract upper airway obstruction, reduce hypoventilation and atelectasis, improve gas exchange and respiratory function, relieve dyspnea, and decrease breathing effort in obese patients in the perioperative period. Thus, NIV may lower the risk of acute respiratory failure after bariatric surgery. Selecting the appropriate interface and type of NIV is fundamental for increasing the likelihood of NIV success in such high-risk patients. NIV is a safe therapy, which should be considered in the perioperative period to help optimize the management of obese patients undergoing bariatric surgery and improve their postoperative course.

Noninvasive Ventilation in Patients with Severe Community-Acquired Pneumonia: What Have We Learned? Key Response Determinants and Practical Implications

Severe community-acquired pneumonia leads to acute respiratory failure, which may require tracheal intubation and mechanical ventilation while proper antibiotic therapy is being established. In an appropriate setting, noninvasive ventilation may be considered for patients with severe community-acquired pneumonia following careful patient selection according to the available guidelines. These patients require constant assessment, evaluating the risk factors for noninvasive ventilation failure.

Assessment of Cognitive Function After Critical Care: Potential Issues

To the Editor, We read with great interest the article by Porhomayon et al. [1] in which the authors discussed the impact of sedation on cognitive function in mechanically ventilated patients. This article represents an interesting contribution in this constantly evolving research field, as the authors carried out a thorough review of both early and late neuropsychological effects of sedation in the intensive care setting. However, some important issues about the review deserve consideration, in particular regarding the assessment of late cognitive alterations. First, the authors stated that their work focused on intensive care patients. Nevertheless, in this review, about 39 % of the patients included for the assessment of posttraumatic stress disorder (PTSD) were admitted to the intensive care unit (ICU) after surgery. Furthermore, they included also patients after cardiac surgery, and one of the studies was conducted entirely on trauma patients [2]. Various cognitive disorders may affect postoperative patients. Postoperative cognitive dysfunction (POCD), a disorder characterized by alterations of memory, concentration, language comprehension and social integration, affects up to 17 % of patients after non-cardiac surgery and up to 39 % of patients after cardiac surgery at 3 months [3]. In such population, the development of cognitive disorders may have had multifactorial origin, to which sedation may have contributed to varying degrees. Second, a follow-up examination is needed to diagnose PTSD. Unfortunately, the need to contact patients after discharge may pose some problems, as a number of subjects might skip follow-up interviews. Interestingly, in other studies measuring cognitive dysfunction after surgery, patients with executive function impairment at discharge from hospital were more prone to avoid further testing [4]. We think that it is important to underline that the studies included in this review have drop-out rates as high as 70 %, which might have affected the results. Finally, timing of assessment could also be important. Currently the diagnosis of PTSD ismade if symptoms persist for more than 1 month, and a further classification splits the disorder into acute (symptoms lasting up to 3 months) and chronic form (symptoms lasting more than 3 months). Moreover, late-onset PTSD has been described within the survivors of critical illness [5], with symptoms presenting and evolving differently up to 6 months after discharge. The studies reported by the authors assessed the prevalence of PTSD at different time points, with a median of 7.5 months, but ranging from 1 month up to 2 years after discharge from the ICU. Thismight both underestimate and overestimate the incidence of the different forms of PTSD. Almost universally critical care patients undergo sedation when mechanical ventilation is needed. Porhomayon et al. [1] summarized the impact of this practice on patients’ cognition, including the recent insights with respect to available drugs and sedation protocols. Unfortunately, it may be difficult to compare studies that assess cognitive alterations in different populations at diverse time points. Interpreting the data available in this research field might be easier if we define both the characteristics of the studied population and the treatments they underwent. & Francesco Zarantonello fzarantonello@gmail.com

Dose of sugammadex in morbidly obese patients

I thank Drs. Dalay and Jagannathan for their interest in our study, which compared nerve stimulation with ultrasound guidance for infraclavicular catheter placement [1]. We agree that patients with higher BMI may benefit from regional anesthesia, even though the risk of block failure is higher [2, 3]. We excluded very obese patients (BMI > 35 kg.m ) in order to reduce the contribution of obesity as a confounding factor in our comparison. However, we did include overweight (BMI 25.0–29.9 kg.m ) and obese (BMI 30.0–34.9 kg.m ) participants, as it would have been unreasonable to exclude them, given rates of obesity within the general population. Effectively, therefore, we excluded approximately 8–11% of potential participants, based on Canadian population statistics for obesity [4]. With regard to using ultrasound and nerve stimulation together, the present study originated from a previous, small study in which we compared dual guidance with nerve stimulation [5]. As the usefulness of dual guidance is debatable [6, 7], we designed the present study to compare only one method of guidance with the other. We retained equipoise when comparing complications between the two techniques, as there appears to be no difference in neurological injury between ultrasound and nerve stimulator-guided peripheral nerve blockade [8].