Impact of Coronavirus Disease 2019 Pandemic on Crowding: A Call to Action for Effective Solutions to “Access Block”

Introduction

Healthcare patterns change during disease outbreaks and pandemics. Identification of modified patterns is important for future preparedness and response. Emergency department (ED) crowding can occur because of the volume of patients waiting to be seen, which results in delays in patient assessment or treatment and impediments to leaving the ED once treatment is complete. Therefore, ED crowding has become a growing problem worldwide and represents a serious barrier to healthcare operations.

Methods

This observational study was based on a retrospective review of the epidemiologic and clinical records of patients who presented to the Foundation IRCCS Policlinic San Matteo in Pavia, Italy, during the coronavirus disease 2019 (COVID-19) outbreak (February 21–May 1, 2020, pandemic group). The methods involved an estimation of the changes in epidemiologic and clinical data from the annual baseline data after the start of the COVID-19 pandemic.

Results

We identified reduced ED visits (180 per day in the control period vs 96 per day in the pandemic period; P < 0.001) during the COVID-19 pandemic, irrespective of age and gender, especially for low-acuity conditions. However, patients who did present to the ED were more likely to be hemodynamically unstable, exhibit abnormal vital signs, and more frequently required high-intensity care and hospitalization. During the pandemic, ED crowding dramatically increased primarily because of an increased number of visits by patients with high-acuity conditions, changes in patient management that prolonged length of stay, and increased rates of boarding, which led to the inability of patients to gain access to appropriate hospital beds within a reasonable amount of time. During the pandemic, all crowding output indices increased, especially the rates of boarding (36% vs 57%; P < 0.001), “access block” (24% vs 47%; P < 0.001), mean boarding time (640 vs 1,150 minutes [min]; P 0.001), mean “access block” time (718 vs 1,223 min; P < 0.001), and “access block” total time (650,379 vs 1,359,172 min; P < 0.001).

Conclusion

Crowding in the ED during the COVID-19 pandemic was due to the inability to access hospital beds. Therefore, solutions to this lack of access are required to prevent a recurrence of crowding due to a new viral wave or epidemic.

End-tidal carbon dioxide (ETCO2) and ventricular fibrillation amplitude spectral area (AMSA) for shock outcome prediction in out-of-hospital cardiac arrest. Are they two sides of the same coin?

AIM

Ventricular fibrillation amplitude spectral area (AMSA) and end-tidal carbon dioxide (ETCO₂) are predictors of shock success, understood as restoration of an organized rhythm, and return of spontaneous circulation (ROSC). However, little is known about their combined use. We aimed to assess the prediction accuracy when combined, and to clarify if they are correlated in out of hospital cardiac arrest' victims.

MATERIALS AND METHODS

Records acquired by external defibrillators in out-of-hospital cardiac arrest patients of the Lombardia Cardiac Arrest registry were processed. The 1-min pre-shock ETCO₂ median value (METCO₂) was computed from the capnogram and AMSA (2-48 mV.Hz range) computed applying the Fast Fourier Transform to a 2-second pre-shock filtered ECG interval (0.5-30 Hz). Support Vector Machine (SVM) predictive models based on METCO₂, AMSA and their combination were fit; results were given as the area under the curve (AUC) of the receiver operating characteristic (ROC) curves.

RESULTS

We considered 112 patients with 391 shocks delivered. METCO₂ and AMSA were predictors of shock success [AUC (IQR) of the ROC curve: 0.59 (0.56-0.62); 0.68 (0.65-0.72), respectively] and of ROSC [0.56 (0.53-0.59); 0.74 (0.71-0.78),]. Their combination in a SVM model increased the accuracy for predicting shock success [AUC (IQR) of the ROC curve: 0.71 (0.68-0.75)] and ROSC [0.77 (0.73-0.8)]. AMSA and METCO₂ were significantly correlated only in patients who achieved ROSC (rho = 0.33 p = 0.03).

CONCLUSIONS

AMSA and ETCO₂ predict shock success and ROSC after every shock, and their predictive power increases if combined. Notably, they were correlated only in patients who achieved ROSC.

Use of critical care resources during the first 2 weeks (February 24-March 8, 2020) of the Covid-19 outbreak in Italy

Background

A Covid-19 outbreak developed in Lombardy, Veneto and Emilia-Romagna (Italy) at the end of February 2020. Fear of an imminent saturation of available ICU beds generated the notion that rationing of intensive care resources could have been necessary.

Results

In order to evaluate the impact of Covid-19 on the ICU capacity to manage critically ill patients, we performed a retrospective analysis of the first 2 weeks of the outbreak (February 24–March 8). Data were collected from regional registries and from a case report form sent to participating sites. ICU beds increased from 1545 to 1989 (28.7%), and patients receiving respiratory support outside the ICU increased from 4 (0.6%) to 260 (37.0%). Patients receiving respiratory support outside the ICU were significantly older [65 vs. 77 years], had more cerebrovascular (5.8 vs. 13.1%) and renal (5.3 vs. 10.0%) comorbidities and less obesity (31.4 vs. 15.5%) than patients admitted to the ICU. PaO₂/FiO₂ ratio, respiratory rate and arterial pH were higher [165 vs. 244; 20 vs. 24 breath/min; 7.40 vs. 7.46] and PaCO₂ and base excess were lower [34 vs. 42 mmHg; 0.60 vs. 1.30] in patients receiving respiratory support outside the ICU than in patients admitted to the ICU, respectively.

Conclusions

Increase in ICU beds and use of out-of-ICU respiratory support allowed effective management of the first 14 days of the Covid-19 outbreak, avoiding resource rationing.

Baseline Characteristics and Outcomes of 1591 Patients Infected With SARS-CoV-2 Admitted to ICUs of the Lombardy Region, Italy

IMPORTANCE

In December 2019, a novel coronavirus (severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]) emerged in China and has spread globally, creating a pandemic. Information about the clinical characteristics of infected patients who require intensive care is limited.

OBJECTIVE

To characterize patients with coronavirus disease 2019 (COVID-19) requiring treatment in an intensive care unit (ICU) in the Lombardy region of Italy.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective case series of 1591 consecutive patients with laboratory-confirmed COVID-19 referred for ICU admission to the coordinator center (Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy) of the COVID-19 Lombardy ICU Network and treated at one of the ICUs of the 72 hospitals in this network between February 20 and March 18, 2020. Date of final follow-up was March 25, 2020.

EXPOSURES

SARS-CoV-2 infection confirmed by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay of nasal and pharyngeal swabs.

MAIN OUTCOMES AND MEASURES

Demographic and clinical data were collected, including data on clinical management, respiratory failure, and patient mortality. Data were recorded by the coordinator center on an electronic worksheet during telephone calls by the staff of the COVID-19 Lombardy ICU Network.

RESULTS

Of the 1591 patients included in the study, the median (IQR) age was 63 (56-70) years and 1304 (82%) were male. Of the 1043 patients with available data, 709 (68%) had at least 1 comorbidity and 509 (49%) had hypertension. Among 1300 patients with available respiratory support data, 1287 (99% [95% CI, 98%-99%]) needed respiratory support, including 1150 (88% [95% CI, 87%-90%]) who received mechanical ventilation and 137 (11% [95% CI, 9%-12%]) who received noninvasive ventilation. The median positive end-expiratory pressure (PEEP) was 14 (IQR, 12-16) cm H2O, and Fio2 was greater than 50% in 89% of patients. The median Pao2/Fio2 was 160 (IQR, 114-220). The median PEEP level was not different between younger patients (n = 503 aged ≤63 years) and older patients (n = 514 aged ≥64 years) (14 [IQR, 12-15] vs 14 [IQR, 12-16] cm H2O, respectively; median difference, 0 [95% CI, 0-0]; P = .94). Median Fio2 was lower in younger patients: 60% (IQR, 50%-80%) vs 70% (IQR, 50%-80%) (median difference, -10% [95% CI, -14% to 6%]; P = .006), and median Pao2/Fio2 was higher in younger patients: 163.5 (IQR, 120-230) vs 156 (IQR, 110-205) (median difference, 7 [95% CI, -8 to 22]; P = .02). Patients with hypertension (n = 509) were older than those without hypertension (n = 526) (median [IQR] age, 66 years [60-72] vs 62 years [54-68]; P < .001) and had lower Pao2/Fio2 (median [IQR], 146 [105-214] vs 173 [120-222]; median difference, -27 [95% CI, -42 to -12]; P = .005). Among the 1581 patients with ICU disposition data available as of March 25, 2020, 920 patients (58% [95% CI, 56%-61%]) were still in the ICU, 256 (16% [95% CI, 14%-18%]) were discharged from the ICU, and 405 (26% [95% CI, 23%-28%]) had died in the ICU. Older patients (n = 786; age ≥64 years) had higher mortality than younger patients (n = 795; age ≤63 years) (36% vs 15%; difference, 21% [95% CI, 17%-26%]; P < .001).

CONCLUSIONS AND RELEVANCE

In this case series of critically ill patients with laboratory-confirmed COVID-19 admitted to ICUs in Lombardy, Italy, the majority were older men, a large proportion required mechanical ventilation and high levels of PEEP, and ICU mortality was 26%.

Load distributing band device for mechanical chest compressions: An Utstein-categories based analysis of survival to hospital discharge

PURPOSE

The role of load distributing band device (LDB, AutoPulse®, Zoll Medical Corporation, Chelmsford, MA, USA) in out-of-hospital cardiac arrest is still a matter of debate, with few studies reaching conflicting results available in literature. We sought to assess whether the use of the LBD device could affect survival to hospital discharge in the different Utstein categories.

MATERIALS AND METHODS

All consecutive patients enrolled in our provincial cardiac arrest registry (Pavia CARe) from January 2015 to December 2017 were included and pre-hospital data were computed as well as survival to hospital discharge.

RESULTS

Among 1401 resuscitation attempts, the LDB device was used in 235 (17%) patients. The LDB device was significantly more used for shockable cardiac arrest (42.6% vs 13.7%, p < 0.001). The rate of ROSC and of survival to hospital discharge in the LDB group compared to the manual group was 40% vs 17% (p < 0.001) and 10% vs 7% (p = 0.2), respectively. However, after correction for independent predictors of LDB use, LDB device was a strong independent predictor of survival to hospital discharge only for non-shockable witnessed OHCA [n = 624/1401, OR 11.9 (95% CI 1.5-95.2), p = 0.02]. In this categories of patients LDB group showed longer resuscitation time [49.3 min (IQR 37-71) vs 23.6 (IQR 15-35), p < 0.001] and a higher rate of conversion to a shockable rhythm (33/83 = 40% vs 29/541 = 5%, p < 0.001).

CONCLUSION

Utstein categories-based analysis showed that the LDB device positively affect survival to hospital discharge for non-shockable witnessed cardiac arrests with a neutral effect for shockable rhythms.

Right ventricular total isovolumic time: Reference value study

BACKGROUND

There is lack of noninvasive indices to detail the right side cardiovascular physiology. Total isovolumic time (tIVT) is a sensitive marker of left ventricular electromechanical efficiency and systolic-diastolic interaction. The aim of the study was to evaluate normal reference value of the right ventricular tIVT with increasing age.

METHODS AND RESULTS

One hundred and eighty-one healthy volunteers (51% male) underwent transthoracic echocardiography. The population was divided into four categories according to age: A < 30 years; B 30-39 years; C 40-49 years; and C ≥ 50 years old. tIVT was computed in seconds/minutes as: 60 - (tET + tFT). tET and tFT are the total ejection and filling time adjusted by the heart rate, measured, respectively, from the onset to the end of the right ventricle (RV) forward flow through the pulmonary valve and from the onset of the E-wave and the end of the A-wave at the level of the tricuspid valve. The mean RV tIVT was 7 ± 1.1 s/min and increased significantly with age, from a 3.4 to 9.7 s/min(P < 0.0001). Significant correlation was found between tIVT and trans-tricuspid E/E' (P < 0.0001; 0.78 (95% CI: 0.715-0.831) while weaker between tIVT and E/A (P = 0.001; -0.283 95% CI: -0.413 to -0.143).

CONCLUSION

The normal values of RV tIVT increase with age and correlate significantly with Doppler diastolic parameters.

Navigating Market Authorization: The Path Holoclar Took to Become the First Stem Cell Product Approved in the European Union

Gene therapy, cell therapy, and tissue engineering have the potential to revolutionize the treatment of disease and injury. Attaining marketing authorization for such advanced therapy medicinal products (ATMPs) requires a rigorous scientific evaluation by the European Medicines Agency—authorization is only granted if the product can fulfil stringent requirements for quality, safety, and efficacy. However, many ATMPs are being provided to patients under alternative means, such as “hospital exemption” schemes. Holoclar (ex vivo expanded autologous human corneal epithelial cells containing stem cells), a novel treatment for eye burns, is one of the few ATMPs to have been granted marketing authorization and is the first containing stem cells. This review highlights the differences in standards between an authorized and unauthorized medicinal product, and specifically discusses how the manufacture of Holoclar had to be updated to achieve authorization. The result is that patients will have access to a therapy that is manufactured to high commercial standards, and is supported by robust clinical safety and efficacy data. stemcellstranslationalmedicine2018;7:146–154

Veno-venous ECMO during surgical repair of tracheal perforation: A case report

•

Airway management during surgical repair of iatrogenic tracheal injury can be difficult.

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ECMO has emerged as a valid tool to maintain adequate oxygenation during tracheal surgery.

•

Veno-venous ECMO allows a safer peri and intraoperative management of iatrogenic tracheal injuries.

Introduction

Extracorporeal membrane oxygenation (ECMO) is used extensively in cardiothoracic surgery both for hemodynamic and respiratory support. It has proven to be a valuable tool to maintain adequate oxygenation during tracheal surgery. Airway lesion may be an indication for veno-venous ECMO both in case of conservative management and in case of surgical repair. Here we report the case of a patient with a iatrogenic tracheal injury, successfully operated with the support of veno-venous extracorporeal oxygenation.

Presentation of case

A 39-year-old female underwent an elective laparoscopic adhesiolysis. At the end of the procedure, the patient had developed subcutaneous emphysema. A CT-scan showed mediastinal and subcutaneous emphysema and left pneumothorax with a laceration of the membranous portion of the middle third of the trachea.

A left pleural drain was inserted and a bronchoscopy showed a 2-cm long tear of the membranous portion in the middle third of the trachea.

Veno-venous ECMO was established and surgical repair of the tracheal lesion was performed. Post-operative recovery was uneventful and the patient was discharged on 8th postoperative day.

Discussion

The use of Veno-venous ECMO allowed a safe intubation with optimal oxygenation. A selective intubation with a small tube was performed to prevent further tracheal injury and allow an adequate surgical space for tracheal repair.

Conclusion

The use of ECMO support represents a safe and effective way to manage patients with ITI when surgical repair with minimally invasive ventilation is needed.

Since this is a case report larger studies are needed to validate the technique.

Randomized, multicenter trial of lateral Trendelenburg versus semirecumbent body position for the prevention of ventilator-associated pneumonia

PURPOSE

The lateral Trendelenburg position (LTP) may hinder the primary pathophysiologic mechanism of ventilator-associated pneumonia (VAP). We investigated whether placing patients in the LTP would reduce the incidence of VAP in comparison with the semirecumbent position (SRP).

METHODS

This was a randomized, multicenter, controlled study in invasively ventilated critically ill patients. Two preplanned interim analyses were performed. Patients were randomized to be placed in the LTP or the SRP. The primary outcome, assessed by intention-to-treat analysis, was incidence of microbiologically confirmed VAP. Major secondary outcomes included mortality, duration of mechanical ventilation, and intensive care unit length of stay.

RESULTS

At the second interim analysis, the trial was stopped because of low incidence of VAP, lack of benefit in secondary outcomes, and occurrence of adverse events. A total of 194 patients in the LTP group and 201 in the SRP group were included in the final intention-to-treat analysis. The incidence of microbiologically confirmed VAP was 0.5% (1/194) and 4.0% (8/201) in LTP and SRP patients, respectively (relative risk 0.13, 95% CI 0.02-1.03, p = 0.04). The 28-day mortality was 30.9% (60/194) and 26.4% (53/201) in LTP and SRP patients, respectively (relative risk 1.17, 95% CI 0.86-1.60, p = 0.32). Likewise, no differences were found in other secondary outcomes. Six serious adverse events were described in LTP patients (p = 0.01 vs. SRP).

CONCLUSIONS

The LTP slightly decreased the incidence of microbiologically confirmed VAP. Nevertheless, given the early termination of the trial, the low incidence of VAP, and the adverse events associated with the LTP, the study failed to prove any significant benefit. Further clinical investigation is strongly warranted; however, at this time, the LTP cannot be recommended as a VAP preventive measure. CLINICALTRIALS.

GOV IDENTIFIER

NCT01138540.

Frequency of respiratory virus infections and next-generation analysis of influenza A/H1N1pdm09 dynamics in the lower respiratory tract of patients admitted to the ICU

Recent molecular diagnostic methods have significantly improved the diagnosis of viral pneumonia in intensive care units (ICUs). It has been observed that 222G/N changes in the HA gene of H1N1pdm09 are associated with increased lower respiratory tract (LRT) replication and worse clinical outcome. In the present study, the frequency of respiratory viruses was assessed in respiratory samples from 88 patients admitted to 16 ICUs during the 2014–2015 winter-spring season in Lombardy. Sixty-nine out of 88 (78.4%) patients were positive for a respiratory viral infection at admission. Of these, 57/69 (82.6%) were positive for influenza A (41 A/H1N1pdm09 and 15 A/H3N2), 8/69 (11.6%) for HRV, 2/69 (2.9%) for RSV and 2/69 (2.9%) for influenza B. Phylogenetic analysis of influenza A/H1N1pdm09 strains from 28/41 ICU-patients and 21 patients with mild respiratory syndrome not requiring hospitalization, showed the clear predominance of subgroup 6B strains. The median influenza A load in LRT samples of ICU patients was higher than that observed in the upper respiratory tract (URT) (p<0.05). Overall, a greater number of H1N1pdm09 virus variants were observed using next generation sequencing on partial HA sequences (codons 180–286) in clinical samples from the LRT as compared to URT. In addition, 222G/N/A mutations were observed in 30% of LRT samples from ICU patients. Finally, intra-host evolution analysis showed the presence of different dynamics of viral population in LRT of patients hospitalized in ICU with a severe influenza infection.

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016

[This corrects the article DOI: 10.1186/s13054-016-1208-6.].

Long-Term Retrospective Analysis of Gene Therapy with Alipogene Tiparvovec and Its Effect on Lipoprotein Lipase Deficiency-Induced Pancreatitis

Alipogene tiparvovec (Glybera) is a gene therapy product approved in Europe under the "exceptional circumstances" pathway as a treatment for lipoprotein lipase deficiency (LPLD), a rare genetic disease resulting in chylomicronemia and a concomitantly increased risk of acute and recurrent pancreatitis, with potentially lethal outcome. This retrospective study analyzed the frequency and severity of pancreatitis in 19 patients with LPLD up to 6 years after a single treatment with alipogene tiparvovec. An independent adjudication board of three pancreas experts, blinded to patient identification and to pre- or post-gene therapy period, performed a retrospective review of data extracted from the patients' medical records and categorized LPLD-related acute abdominal pain events requiring hospital visits and/or hospitalizations based on the adapted 2012 Atlanta diagnostic criteria for pancreatitis. Both entire disease time period data and data from an equal time period before and after gene therapy were analyzed. Events with available medical record information meeting the Atlanta diagnostic criteria were categorized as definite pancreatitis; events treated as pancreatitis but with variable levels of laboratory and imaging data were categorized as probable pancreatitis or acute abdominal pain events. A reduction of approximately 50% was observed in all three categories of the adjudicated post-gene therapy events. Notably, no severe pancreatitis and only one intensive care unit admission was observed in the post-alipogene tiparvovec period. However, important inter- and intraindividual variations in the pre- and post-gene therapy incidence of events were observed. There was no relationship between the posttreatment incidence of events and the number of LPL gene copies injected, the administration of immunosuppressive regimen or the percent triglyceride decrease achieved at 12 weeks (primary end point in the prospective clinical studies). Although a causal relationship cannot be established and despite the limited number of individuals evaluated, results from this long-term analysis suggest that alipogene tiparvovec was associated with a lower frequency and severity of pancreatitis events, and a consequent overall reduction in health care resource use up to 6 years posttreatment.

Prep1 (pKnox1) regulates mouse embryonic HSC cycling and self-renewal affecting the Stat1-Sca1 IFN-dependent pathway

A hypomorphic Prep1 mutation results in embryonic lethality at late gestation with a pleiotropic embryonic phenotype that includes defects in all hematopoietic lineages. Reduced functionality of the hematopoietic stem cells (HSCs) compartment might be responsible for the hematopoietic phenotype observed at mid-gestation. In this paper we demonstrate that Prep1 regulates the number of HSCs in fetal livers (FLs), their clonogenic potential and their ability to de novo generate the hematopoietic system in ablated hosts. Furthermore, we show that Prep1 controls the self-renewal ability of the FL HSC compartment as demonstrated by serial transplantation experiments. The premature exhaustion of Prep1 mutant HSCs correlates with the reduced quiescent stem cell pool thus suggesting that Prep1 regulates the self-renewal ability by controlling the quiescence/proliferation balance. Finally, we show that in FL HSCs Prep1 absence induces the interferon signaling pathway leading to premature cycling and exhaustion of fetal HSCs.

Reduction of Prep1 levels affects differentiation of normal and malignant B cells and accelerates Myc driven lymphomagenesis

The Prep1 homeodomain transcription factor has recently been recognized as a tumor suppressor. Among other features, haploinsufficiency of Prep1 is able to strongly accelerate the B-lymphomagenesis in EμMyc mice. Now we report that this occurs concomitantly with a change in the type of B-cell lymphomas generated by the Myc oncogene. Indeed, the tumors generated in the EμMyc-Prep1^+/− mice are much more immature, being mostly made up of Pro-B or Pre-B cells, while those in the EμMyc-Prep1^+/+ mice are more differentiated being invariably IgM⁺. Moreover, we show that Prep1 is in fact required for the differentiation of Pro-B and Pre-B cells into IgM⁺ lymphocytes and/or their proliferation, thus showing also how a normal function of Prep1 affects EμMyc lymphomagenesis. Finally, we show that the haploinsufficiency of Prep1 is accompanied with a major decrease of Myc-induced apoptosis and that the haploinsufficieny is sufficient for all these effects because the second allele of Prep1 is not lost even at late stages. Therefore, the tumor-suppressive activity of Prep1 is intertwined with both the interference with Myc-induced apoptosis as well as with natural developmental functions of the protein.

Severe outcome of influenza A/H1N1/09v infection associated with 222G/N polymorphisms in the haemagglutinin: a multicentre study

In a multicentre study, influenza A/H1N1/09v 222G/N variants were more frequently detected in patients admitted to the intensive-care unit for invasive mechanical ventilation or extracorporeal membrane oxygenation (10/23; 43.5%) than in patients hospitalized in other units (2/27; 7.4%) and community patients (0/81; 0.0%) (p <0.01). A significantly higher virus load (p 0.02) in the lower vs the upper respiratory tract was observed. Predominance of 222G/N variants in the lower respiratory tract (40% of total virus population) vs the upper respiratory tract (10%) was shown by clonal analysis of haemagglutinin sequences in paired nasal swab and bronchoalveolar lavage samples. The time from illness onset to sampling was significantly longer in patients with severe infection vs community patients (p <0.001). It was concluded that the 222G/N variants showed increased virulence; mutant variants were probably selected in individual patients; and the longer duration of illness might have favoured the emergence of adaptive mutations through multiple replication cycles.

The absence of Prep1 causes p53-dependent apoptosis of mouse pluripotent epiblast cells

Disruption of mouse Prep1, which codes for a homeodomain transcription factor, leads to embryonic lethality during post-implantation stages. Prep1(-/-) embryos stop developing after implantation and before anterior visceral endoderm (AVE) formation. In Prep1(-/-) embryos at E6.5 (onset of gastrulation), the AVE is absent and the proliferating extra-embryonic ectoderm and epiblast, marked by Bmp4 and Oct4, respectively, are reduced in size. At E.7.5, Prep1(-/-) embryos are small and very delayed, showing no evidence of primitive streak or of differentiated embryonic lineages. Bmp4 is expressed residually, while the reduced number of Oct4-positive cells is constant up to E8.5. At E6.5, Prep1(-/-) embryos retain a normal mitotic index but show a major increase in cleaved caspase 3 and TUNEL staining, indicating apoptosis. Therefore, the mouse embryo requires Prep1 when undergoing maximal expansion in cell number. Indeed, the phenotype is partially rescued in a p53(-/-), but not in a p16(-/-), background. Apoptosis is probably due to DNA damage as Atm downregulation exacerbates the phenotype. Despite this early lethal phenotype, Prep1 is not essential for ES cell establishment. A differential embryonic expression pattern underscores the unique function of Prep1 within the Meis-Prep family.

Down syndrome fibroblasts and mouse Prep1-overexpressing cells display increased sensitivity to genotoxic stress

PREP1 (PKNOX1) maps in the Down syndrome (DS) critical region of chromosome 21, is overexpressed in some DS tissues and might be involved in the DS phenotype. By using fibroblasts from DS patients and by overexpressing Prep1 in F9 teratocarcinoma and Prep1^i/i MEF to single out the role of the protein, we report that excess Prep1 increases the sensitivity of cells to genotoxic stress and the extent of the apoptosis directly correlates with the level of Prep1. The apoptotic response of Prep1-overexpressing cells is mediated by the pro-apoptotic p53 protein that we show is a direct target of Prep1, as its depletion reverts the apoptotic phenotype. The induction of p53 overcomes the anti-apoptotic role of Bcl-X_L, previously shown to be also a Prep1 target, the levels of which are increased in Prep1-overexpressing cells as well. Our results provide a rationale for the involvement of PREP1 in the apoptotic phenotype of DS tissues and indicate that differences in Prep1 level can have drastic effects.

Prep1 (pKnox1)-deficiency leads to spontaneous tumor development in mice and accelerates EmuMyc lymphomagenesis: a tumor suppressor role for Prep1

The Prep1 homeodomain transcription factor is essential for embryonic development. 25% of hypomorphic Prep1(i/i) embryos, expressing the gene at 2% of the normal levels, survive pregnancy and live a normal-length life. Later in life, however, these mice develop spontaneous pre-tumoral lesions or solid tumors (lymphomas and carcinomas). In addition, transplantation of E14.5 fetal liver (FL) Prep1(i/i) cells into lethally irradiated mice induces lymphomas. In agreement with the above data, haploinsufficiency of a different Prep1-deficient (null) allele accelerates EmuMyc lymphoma growth. Therefore Prep1 has a tumor suppressor function in mice. Immunohistochemistry on tissue micrroarrays (TMA) generated from three distinct human cohorts comprising a total of some 1000 human tumors revealed that 70% of the tumors express no or extremely low levels of Prep1, unlike normal tissues. Our data in mice are thus potentially relevant to human cancer.

The homeodomain transcription factor Prep1 (pKnox1) is required for hematopoietic stem and progenitor cell activity

Most of the hypomorphic Prep1(i/i) embryos (expressing 3-10% of the Prep1 protein), die between E17.5 and P0, with profound anemia, eye malformations and angiogenic anomalies [Ferretti, E., Villaescusa, J.C., Di Rosa, P., Fernandez-Diaz, L.-C., Longobardi, E., Mazzieri, R., Miccio, A., Micali, N., Selleri, L., Ferrari G., Blasi, F. (2006). Hypomorphic mutation of the TALE gene Prep1 (pKnox1) causes a major reduction of Pbx and Meis proteins and a pleiotropic embryonic phenotype. Mol. Cell. Biol. 26, 5650-5662]. We now report on the hematopoietic phenotype of these embryos. Prep1(i/i) fetal livers (FL) are hypoplastic, produce less common myeloid progenitors colonies (CFU-GEMM) in cytokine-supplemented methylcellulose and have an increased number of B-cells precursors that differentiate poorly. Prep1(i/i) FL is able to protect lethally irradiated mice only at high cell doses but the few protected mice show major anomalies in all hematopoietic lineages in both bone marrow (BM) and peripheral organs. Prep1(i/i) FL cells compete inefficiently with wild type bone marrow in competitive repopulation experiments, suggesting that the major defect lies in long-term repopulating hematopoietic stem cells (LTR-HSC). Indeed, wt embryonic expression of Prep1 in the aorta-gonad-mesonephros (AGM) region, fetal liver (FL), cKit(+)Sca1(+)Lin(-)AA4.1(+) (KSLA) cells and B-lymphocytes precursors agrees with the observed phenotype. We therefore conclude that Prep1 is required for a correct and complete hematopoiesis.

Expression of CCL9/MIP-1gamma is repressed by BCR/ABL and its restoration suppresses in vivo leukemogenesis of 32D-BCR/ABL cells

Transformation of hematopoietic cells by the BCR/ABL oncogene is caused by perturbation of signal transduction pathways leading to altered patterns of gene expression and activity. By oligonucleotide microarray hybridization of polysomal RNA of untreated and STI571-treated 32D-BCR/ABL cells, we identified the beta-chemokine CCL9 as a gene regulated by BCR/ABL in a tyrosine kinase-dependent manner. BCR/ABL repressed CCL9 expression at the transcriptional level by mechanisms involving suppression of p38 MAP kinase, and modulation of the activity of CDP/cut and C/EBPalpha, two transcription regulators of myeloid differentiation. However, repression of C/EBP-dependent transcription did not prevent the induction of CCL9 expression by STI571, suggesting that C/EBPalpha is involved in maintaining rather than in inducing CCL9 expression. Restoration of CCL9 expression in 32D-BCR/ABL cells had no effect on the in vitro proliferation of these cells, but reduced their leukemogenic potential in vivo, possibly by recruitment of CD3-positive immune cells. Together, these findings suggest that downregulation of chemokine expression may be involved in BCR/ABL-dependent leukemogenesis by altering the relationship between transformed cells and the microenvironment.

Leukemogenesis induced by wild-type and STI571-resistant BCR/ABL is potently suppressed by C/EBPalpha

Chronic phase-to-blast crisis transition in chronic myelogenous leukemia (CML) is associated with differentiation arrest and down-regulation of C/EBPalpha, a transcription factor essential for granulocyte differentiation. Patients with CML in blast crisis (CML-BC) became rapidly resistant to therapy with the breakpoint cluster region-Abelson murine leukemia (BCR/ABL) kinase inhibitor imatinib (STI571) because of mutations in the kinase domain that interfere with drug binding. We show here that the restoration of C/EBPalpha activity in STI571-sensitive or -resistant 32D-BCR/ABL cells induced granulocyte differentiation, inhibited proliferation in vitro and in mice, and suppressed leukemogenesis. Moreover, activation of C/EBPalpha eradicated leukemia in 4 of 10 and in 6 of 7 mice injected with STI571-sensitive or -resistant 32D-BCR/ABL cells, respectively. Differentiation induction and proliferation inhibition were required for optimal suppression of leukemogenesis, as indicated by the effects of p42 C/EBPalpha, which were more potent than those of K298E C/EBPalpha, a mutant defective in DNA binding and transcription activation that failed to induce granulocyte differentiation. Activation of C/EBPalpha in blast cells from 4 patients with CML-BC, including one resistant to STI571 and BMS-354825 and carrying the T315I Abl kinase domain mutation, also induced granulocyte differentiation. Thus, these data indicate that C/EBPalpha has potent antileukemia effects even in cells resistant to ATP-binding competitive tyrosine kinase inhibitors, and they portend the development of anti-leukemia therapies that rely on C/EBPalpha activation.

[Inhaled nitrous oxide (NO) for the treatment of ARDS]

OBJECTIVE

To investigate the initial longterm effect of inhaled NO on hypoxemia in ARDS patients.

DESIGN

Retrospective study.

PATIENTS

Nine hypoxemic patients with ARDS (Murray Lung Injury Score, LIS, 2.8 +/- 0.3), treated with conventional mechanical ventilation.

INTERVENTIONS

Continuous NO inhalation was started after a test of inhaled NO efficacy on gas exchange and hemodynamics. Long term effects of inhaled NO were evaluated daily in terms of arterial oxygenation and methemoglobin formation.

RESULTS

The initial NO inhalation increased the PaO2/FiO2 from 141 +/- 64 mmHg to 216 +/- 70 mmHg (p < 0.0001) and decreased the mean pulmonary pressure from 38 +/- 7 mmHg to 32 +/- 5 mmHg (p < 0.01), the pulmonary venous admixture from 29 +/- 10% to 20 +/- 8% (p < 0.01) and the pulmonary vascular resistance from 325 +/- 97 dyne.s.cm-5 to 238 +/- 48 dyne.s.cm-5 (p < 0.01). Daily withdrawal of inhaled NO, which was administered for 14 +/- 16 days at 8 +/- 2 ppm, was associated with a decrease in PaO2/FiO2 by 61 +/- 32 mmHg (p < 0.0001). During prolonged NO inhalation the FiO2 was decreased, on average, by 0.34 +/- 0.19 (p < 0.01), the positive end-expiratory pressure by 4 +/- 2 cmH2O (p < 0.01) and the peak inspiratory pressure by 7 +/- 4 cmH2O (p < 0.01). Three patients died during the ICU stay.

CONCLUSIONS

Our results confirm the interest for inhaled NO as an additional approach for the treatment of hypoxemia in ARDS. Inhaled NO seems to allow for a better control of gas exchange, rather than for a rapid reduction of the ventilatory support.

Bronchoalveolar lavage fluid composition in alveolar proteinosis. Early changes after therapeutic lavage

In patients with idiopathic alveolar proteinosis, the alveoli are filled with materials rich in surfactant components, especially surfactant protein A (SP-A). The anomaly could be caused by either increased secretion, decreased clearance, or both. To clarify this point, we studied five patients who underwent therapeutic lavage and then were ventilated mechanically for 24 h. During the first 8 h of mechanical ventilation, a surfactant-depleted lung was lavaged at selected intervals, and the bronchoalveolar lavage fluid was analyzed. We observed that, after lavage, various surfactant components accumulated in the airways with different time courses. We also observed that SP-A increased until the second hour and then dropped rapidly, suggesting the existence of an efficient mechanism of removal. These findings suggest that idiopathic alveolar proteinosis might be caused by a primary defect in a slow mechanism of removal or by the presence of factor(s) that interfere with the clearance of surfactant and that can be removed by lavage. It seems clear, however, that an increased secretion rate is unlikely to be the major cause of idiopathic alveolar proteinosis.

Respiratory response and inspiratory effort during pressure support ventilation in COPD patients

OBJECTIVE

Pressure Support Ventilation (PSV) is now widely used in the process of weaning patients from mechanical ventilation. The aim of this study was to evaluate the effects of various levels of PS on respiratory pattern and diaphragmatic efforts in patients affected by chronic obstructive pulmonary disease (COPD).

SETTING

Intermediate intensive care unit.

PATIENTS

We studied ten patients undergoing PSV and recovering from an episode of acute respiratory failure due to exacerbation of COPD.

METHODS

Three levels of PSV were studied, starting from the lowest (PSb) one at which it was possible to obtain an adequate Vt with a pH > or = 7.32 and an SaO2 > 93%. Then, PS was set at 5 cmH2O above (PSb + 5) and below (PSb-5) this starting level. Ventilatory pattern, transdiaphragmatic pressure (Pdi), the pressure-time product of the diaphragm (PTPdi), the integrated EMG of the diaphragm, static PEEP (PEEPi, stat), dynamic PEEP (PEEPi, dyn), and the static compliance and resistance of the total respiratory system were recorded.

RESULTS

Minute ventilation did not significantly change with variations in the level of PS, while Vt significantly increased with PS (PS-5 = 6.3 +/- 0.5 ml/kg vs. PSb = 10.1 +/- 0.9 [p < 0.01] and vs. PS + 5 = 11.7 +/- 0.6 [p < 0.01]), producing a reduction in respiratory frequency with longer expiratory time. The best values of blood gases were obtained at PSb, while at PSb-5, PaCO2 markedly increased. During PSb and PSb + 5 and to a lesser extent during PSb-5, most of the patients made several inspiratory efforts that were not efficient enough to trigger the ventilator to inspire; thus, the PTPdi "wasted" during these inefficient efforts was increased, especially during PS + 5. The application of an external PEEP (PEEPe) of 75% of the static intrinsic PEEP during PSb caused a significant reduction in the occurrence of these inefficient efforts (p < 0.05). Minute ventilation remained constant, but Vt decreased, together with Te, leaving the blood gases unaltered. The PTPdi per breath and the dynamic PEEPi were also significantly reduced (by 59% and 31% of control, respectively, p < 0.001) with the application of PEEPe.

CONCLUSION

We conclude that in COPD patients, different levels of PSV may induce different respiratory patterns and gas exchange. PS levels capable of obtaining a satisfactory equilibrium in blood gases may result in ineffective respiratory efforts if external PEEP is not applied. The addition of PEEPe, not exceeding dynamic intrinsic PEEP, may also reduce the metabolic work of the diaphragm without altering gas exchange.

Simple method to measure total expiratory time constant based on the passive expiratory flow-volume curve

OBJECTIVE

In intubated, mechanically ventilated patients, inspiration is forced by externally applied positive pressure. In contrast, exhalation is passive and depends on the time constant of the total respiratory system. The expiratory time constant is thus an important determinant of mechanical ventilation. The aim of this study was to evaluate a simple method for measuring the expiratory time constant in ventilated subjects.

DESIGN

Prospective study using a lung simulator and ten dogs.

SETTING

University hospital.

SUBJECTS

Commercially available lung simulator and ten greyhound dogs.

INTERVENTIONS

Different expiratory time constants were set on the lung simulator. In the dogs, the endotracheal tube was clamped to increase airways resistance by 22.5 cm H2O/(L/sec) and the lungs were injured with hydrochloric acid to decrease total respiratory compliance by 16 mL/cm H2O. This procedure resulted in a wide range of expiratory time constants.

MEASUREMENTS AND MAIN RESULTS

Pneumotachography was used to measure flow and volume. The ratio of exhaled volume and peak flow was calculated from these signals, corrected for the limited exhalation time yielding the "calculated expiratory time constant" and compared with the actual expiratory time constant. The typical error was +/- 0.19 sec for the lung simulator and +/- 0.15 sec for the dogs.

CONCLUSIONS

The volume and peak flow corrected for limited exhalation time is a good estimate of the total expiratory time constant in passive subjects and may be useful for the titration of mechanical ventilation.

Elevated static compliance of the total respiratory system: early predictor of weaning unsuccess in severed COPD patients mechanically ventilated

OBJECTIVE

To assess in a group of COPD patients mechanically ventilated for an episode of acute respiratory failure the respiratory mechanics with a simple and non invasive method at the bedside in order to evaluate if these parameters may be predictive of weaning failure or success.

DESIGN

A prospective study.

SETTING

Intensive care and intermediate intensive care units.

PATIENTS

23 COPD patients ventilated for acute respiratory failure and studied within 24 hours from intubation.

METHODS

Using end-expiratory and end-inspiratory airway occlusion technique, we measured PEEPi, static compliance of the respiratory system (Crs, st) maximum respiratory resistance (Rrsmax) and minimum respiratory resistance (Rrsmin).

MEASUREMENTS AND RESULTS

The weaned group (A) and the not weaned group (B) were not different regarding to static PEEPi (group A 8.5 +/- 4.0 vs group B 8.9 +/- 2.6 cmH2O), TO Rrsmax (22.4 +/- 5.3 versus 22.2 +/- 9.0 cmH2O/1/s) and to Rrsmin (17.6 +/- 5.5 versus 17.9 +/- 8.0 cmH2O/1/s), while a significant difference (p < 0.001) has been found in Cst, rs (62.7 +/- 17.% versus 111.6 +/- 18.0 ml/cm H2O). The threshold value of 88.5 ml/cmH2O was identified by discriminant analysis and provided the best separation between the two groups, with a sensitivity of 0.85 and a specificity of 0.87.

CONCLUSION

Cst, rs measured non invasively in the first 24 h from intubation, provided a good separation between the patients who were successfully weaned and those who failed.

[Nitric oxide inhalation test in patients with ARDS: preliminary assessment of the effect on arterial oxygenation]

OBJECTIVE

Inhaled NO can improve arterial oxygenation in ARDS. We evaluated the incidence and the magnitude of this effect during a short test of NO inhalation. This was performed in 24 consecutive mechanically ventilated patients with ARDS in order to assess the interest of NO for the therapy of hypoxemia in each case.

DESIGN

Retro-spective study.

SETTING

ICU in a University Hospital.

PATIENTS

24 hypoxemic patients with ARDS (lung injury score, LIS, 2.9 +/- 0.52), treated with conventional mechanical ventilation.

INTERVENTIONS

Tests were performed using a mean inhalatory NO dose of 14 +/- 6 ppm. A pair of PaO2 data was obtained for each patient from two blood gas analysis, performed one just before and one 15 min after the start of NO inhalation.

RESULTS

The mean baseline PaO2 was 76 +/- 21 mmHg and significantly increased with NO inhalation to 97 +/- 34 mmHg (p = 0.0001). Considering the individual response to NO, patients were arbitrarily classified as responders when the increase of PaO2 from baseline was > or = 10%. Sixteen patients were identified as responders, showing a mean increase of PaO2 from baseline by 40 +/- 26%, while the remaining 8 patients resulted non responders (mean change 1 +/- 5.7%). In no case a clinically significant decrease of PaO2 was observed during NO inhalation. The response to NO did not correlate with the LIS (r = 0.019) and with baseline PaO2 (r = 0.31).

CONCLUSIONS

Inhaled NO doses of 14 +/- 6 ppm increased on the average the PaO2 in a group of ARDS patients, the individual response being however variable. A deterioration of arterial oxygenation was never observed. Even if the criteria for predicting the response to NO still remain to be defined, a short test seems to reliably provide a first estimate of the magnitude of the response.

Whole lung lavage

Bronchoalveolar lavage is universally employed as a diagnostic procedure and also, both in the massive (whole lung) and limited forms, has important therapeutic applications. Since the second half of the century whole lung lavage (WLL) has been applied in patients with pulmonary alveolar proteinosis and has proved successful. The procedure has improved over the years in terms of safety and efficacy, whilst indications and methods for WLL are not yet completely defined and standardized. In this paper, we summarize the history of the development of WLL, and describe the procedure used eight times in five patients in our department.

Body iron status in critically ill patients: significance of serum ferritin

Serial measurements of blood haemoglobin, serum iron, serum transferrin, total iron-binding capacity, transferrin per cent saturation and serum ferritin were determined in 51 post-operative critically ill patients to investigate body iron status in severely stressed patients. The results showed decreased blood haemoglobin, serum iron, serum transferrin and transferrin saturation compared to an increase in serum ferritin levels. These results indicate that there is inadequate availability of iron to tissues (secondary to rearrangement of body iron to the advantage of the iron storage compartment), which is often present in severely critically ill patients. A positive correlation was found between the initial (ferritin) levels and SAPS (r = 0.41, p less than 0.01). In addition, the increase of ferritin concentration parallels a worsening of the clinical status in severely ill patients. This is due to enhanced release by the macrophage system. From this, we consider serum ferritin as an acute-phase protein and a useful marker of the severity of the clinical status. It appears to be useful in predicting the patient's outcome, but is not reliable in evaluating iron stores in stressed patients.

A continuous flow intermittent mandatory ventilation with continuous positive airway pressure circuit with high-compliance reservoir bag

Unstable inspiratory pressure may reduce the benefits of intermittent mandatory ventilation and impose a greater work of breathing than some patients can tolerate. The authors evaluated a continuous flow intermittent mandatory ventilation with continuous positive airway pressure apparatus provided with a 10-L high compliance reservoir bag, separated from the ventilator circuit by a one-way valve. A pulmonary simulator was tested to generate a wide range of inspiratory peak flow rates. Pressures and flow rates were examined in different sections of the system, using PEEP levels up to 15 mm Hg and different fresh gas flow rates. The circuit offers many advantages, particularly considering the low inspiratory pressure drop and the low fresh gas flow rates needed for optimal function.

Bedside evaluation of right ventricular performance using a rapid computerized thermodilution method

In 34 patients, we assessed the reproducibility and accuracy of a new, computerized, thermodilution method that determines right ventricular ejection fraction (RVEF). We compared the results from this new algorithm with simultaneous results from the conventional plateau thermodilution method and from both first-pass and gated nuclear techniques. Using this new method improved the reproducibility of thermal determinations of RVEF. Although the thermal values were lower, the correlations between thermal and nuclear measurements were close [r = .92 (first-pass technique), r = .81 (gated technique)]. This new method seems particularly appropriate for serial monitoring of RV performance.