Rate of Change of Rapid Shallow Breathing Index and Extubation Outcome in Mechanically Ventilated Patients.

Background: Rapid shallow breathing index (RSBI) has been widely used as a predictor of extubation outcome in mechanically ventilated patients. We hypothesize that the rate of change of RSBI between the beginning and end of a 120-minute spontaneous breathing trial (SBT) could be a better predictor of extubation outcome than a single RSBI measured at the end of SBT in mechanically ventilated patients. Methodology. In this prospective observational study, we enrolled 193 patients who met the inclusion criteria, of whom 33 patients were unable to tolerate a 120-minute SBT and were excluded from the study. The study population consisted of 160 patients, categorized into three subgroups: patients with normal lung (no reported history of respiratory diseases), patients with airway disease, and patients with parenchymal disease who completed 120 minutes of SBT on low levels of pressure support ventilation. RSBI was obtained from the ventilator display at the 5th and the 120th minutes of SBT. The rate of change of RSBI (RSBI 5-120) was calculated as (RSBI 2-RSBI 1)/RSBI 1 × 100. Receiver-operating characteristic (ROC) curves were plotted for RSBI 5-120 and RSBI 120 in all patients and among the three subgroups (normal group, airway group, and parenchymal group) to compare the superiority of their best thresholds in predicting extubation failure. Results: The RSBI 5-120 threshold for extubation failure in the entire patient group was 23% with an overall accuracy of 88% (AUC = 0.933, sensitivity = 91%, and specificity = 86%) and the threshold of RSBI 120 for extubation failure in the entire patient group was 70 breaths/min/L with an overall accuracy of 82% (AUC = 0.899, sensitivity = 85%, and specificity = 81%). In patients in the normal lung group, the threshold of RSBI 5-120 was 22%, with an overall accuracy of 89% (AUC = 0.892, sensitivity = 87.5%, and specificity = 90%), and the RSBI 120 threshold was 70 breaths/min/L, with an overall accuracy of 89% (AUC = 0.956, sensitivity = 88%, and specificity = 90%). The RSBI 5-120 threshold in patients with airway disease was 25% with an accuracy of 86% (AUC = 0.892, sensitivity = 85%, and specificity = 86%) and the threshold of RSBI 120 was 73 breaths/min/L with an accuracy of 83% (AUC = 0.874, sensitivity = 85%, and specificity = 82%). In patients in the parenchymal disease group, the threshold of RSBI 5-120 was 24%, with an accuracy of 90% (AUC = 0.966, sensitivity = 92%, and specificity = 89%) and RSBI 120 threshold was 71 breaths/min/L, which was 88% accurate (AUC = 0.893, sensitivity = 85%, and specificity = 89%). Conclusion: The rate of change of RSBI between the 5th and 120th minutes was moderately more accurate than the single value of RSBI measured at the 120th minute in predicting extubation outcome.

Lung Ultrasound: The Emerging Role of Respiratory Therapists.

Lung ultrasound is a point-of-care imaging tool that is routinely used in acute care medicine. Traditionally, radiology physicians were the primary practitioners of diagnostic ultrasound, but with the recognition of its importance in intensive care medicine, critical care physicians have also adopted this practice. Within the intensive care unit inter-professional team is the respiratory therapist, who participates actively in the care of ventilated patients. Their scope of responsibility is expanding with newer technologies being brought into clinical use on a regular basis. This review focuses on the scope and benefits of ultrasound training within respiratory care-related areas.

Rapid shallow breathing index.

Predicting successful liberation of patients from mechanical ventilation has been a focus of interest to clinicians practicing in intensive care. Various weaning indices have been investigated to identify an optimal weaning window. Among them, the rapid shallow breathing index (RSBI) has gained wide use due to its simple technique and avoidance of calculation of complex pulmonary mechanics. Since its first description, several modifications have been suggested, such as the serial measurements and the rate of change of RSBI, to further improve its predictive value. The objective of this paper is to review the utility of RSBI in predicting weaning success. In addition, the use of RSBI in specific patient populations and the reported modifications of RSBI technique that attempt to improve the utility of RSBI are also reviewed.

EXTRA CORPOREAL MEMBRANE OXYGENATION IN ACUTE RESPIRATORY DISTRESS SYNDROME.

A young female presented with pneumonitis and worsened acute respiratory distress syndrome (ARDS) failed all the conservative ventilator management, was managed with extra corporeal life support technology, and was successfully discharged.

Severe Neurotoxic Envenoming and Cardiac Complications after the Bite of a 'Sind Krait' (Bungarus cf. sindanus) in Maharashtra, India.

We report a case of severe envenoming with unusual complications and two anecdotal cases of fatalities following proven 17-scale-row 'Sind krait' (Bungarus cf. sindanus) bites on people sleeping in temporary huts at construction sites in Pune District, Maharashtra, India. A 25-yr-old male developed progressive neuromuscular paralysis, abdominal pain and autonomic disturbances complicated by four prolonged episodes of pulseless ventricular tachycardia requiring defibrillation, and followed by pulmonary edema secondary to impaired left ventricular systolic function and hyperfusion. There was no response to antivenom; mechanical ventilation was required for six days. Only one other case of fatal envenoming likely caused by this species had been reported previously in India. The distribution of B. sindanus sensu lato from eastern Afghanistan to India overlaps with that of the superficially very similar common krait (Bungarus caeruleus). Thus, B. cf. sindanus envenoming may be common but routinely overlooked or misdiagnosed.

Can we predict intensive care relatives at risk for posttraumatic stress disorder?

AIMS: To identify the relatives of the intensive care unit (ICU) patients at risk for developing symptoms of posttraumatic stress disorders. SETTING: A multidisciplinary hospital ICU. DESIGN: Prospective single center observational study. MATERIAL AND METHODS: Relatives of patients admitted in the ICU (May06-Nov06) who consented to answer the questionnaire participated in the study. Anxiety was assessed by using the Hospital Anxiety and Depression Scale (HAD) and vulnerability to posttraumatic disorder (PTSD) by using the Impact of Event Scale Revised (IES-R) which was administered on the fifth day of admission and at two months following discharge or death. RESULTS: During admission, 48% of the relatives had a HAD score >11 and 72% showed IES-R score >26. There was no association of HAD with gender, patient outcome, working status, age of the patient, or mode of payment of the bills. There was significant association of IES-R >26 with trauma admission, HAD score >11 and mode of payment with the relatives of insured being more stressed as compared to those who settled their bills personally. A total of 35% relatives showed symptoms of posttraumatic stress reaction consistent with a high risk of PTSD after two months. Death in the hospital resulted in elevated HAD and IES-R score during admission and at the two month follow-up. Persistence of stress symptoms was more in school drop outs, working relatives, parents and those with initial anxiety score >11. CONCLUSIONS: HAD score greater than 11 was the only factor at admission which could statistically predict a higher PTSD score on follow-up. Adequate counseling of this group of relatives may prevent lasting psychological sequelae of an ICU admission in the relatives of critically ill.

Variability of serum phenytoin levels in critically ill head injured patients in intensive care unit.

Patients with large variations in phenytoin levels despite standard doses may prove to become difficult clinical problems. Our study of 34 head injury patients whose serum phenytoin levels were measured on day one and day five following intravenous loading and maintenance dose of phenytoin, showed 38.24% patients, to have therapeutic phenytoin levels on day one, while 20% were in toxic range. On day five, 23% patients were in toxic and 29.41% were in therapeutic range. Only 21% patients remained in the therapeutic range during the monitoring period. This study shows that there is a wide variability of phenytoin levels in the ICU patients with a difference of more than 100% between the highest and lowest phenytoin level in individual cases (in four patients the difference exceeded 500%) raising concern about the safety of the drug. Hence it is recommended that intensive care unit patients receiving phenytoin therapy should have periodic serum phenytoin obtained even in absence of seizures or classic signs phenytoin toxicity.

Acute respiratory failure as a manifestation of an arachnoid cyst.

Arachnoid cysts are the most common congenital cystic lesions in the brain occurring in the middle fossa, suprasellar region and occasionally in the posterior fossa. Conventionally all cysts are considered as benign and symptoms are attributed to expansion of cysts causing compression of adjacent neurological structures, bleeds within the cyst or due to the development of acute hydrocephalus. We are reporting this case of a 15-year-old female patient with non-progressive weakness in the limbs since the age of seven years who presented with acute onset syncopal attacks and respiratory failure. She was intubated and ventilated. An magnetic resonance imaging scan showed large posterior fossa cyst extending up to mid second cervical vertebra causing compression of the medulla and pons, with mild hydrocephalus. After a failed attempt to wean her from the ventilator a cysto peritoneal shunt surgery was performed following which she was weaned from the ventilator successfully. Weakness in the upper and lower limbs, which had increased in the preceding month, also improved following the surgery.

Influenza activity among the paediatric age group in Chennai.

BACKGROUND & OBJECTIVE: Respiratory viral infections have a major impact on public health. Acute respiratory infections largely caused by viruses, are the most common illnesses experienced by otherwise healthy adults and children. Among the respiratory viruses, influenza viruses are known to cause outbreaks globally. Information on the activity of influenza virus in our country is limited and none from Chennai. The present study was carried out to isolate and identify the influenza virus serotypes causing acute respiratory infection in children attending a tertiary care centre at Chennai. METHODS: During January to December 2002, 240 children with acute respiratory infection attending the out patient clinic of Institute of Child Health were included by convenient sampling. Throat swabs were collected from 4 to 5 cases every week. Isolation of influenza virus was attempted by inoculating the sample in Madin Darby Canine Kidney (MDCK) cell line. The isolates were typed by haemagglutination inhibition test and confirmed by immunoflourescence assay. RESULTS: Virus isolation was positive in 30 (12.5%) of the 240 samples. Influenza A/H3N2/Panama/ 2000/99 was the predominant serotype isolated accounting for 24 (80%) of the 30 isolates. Influenza B/Sichuan/379/99 was isolated in 4 (13.33%) and a combination of Influenza A/H3N2 and B/Sichuan in 2 (6.6%) of the isolates. INTERPRETATION & CONCLUSION: Isolation of influenza A and B viruses indicated a significant activity of these viruses in Chennai. Peak activity was observed during and after the first spell of rain. The predominance of A/H3N2/ Panama is an indication that the Indian scenario is similar to the global picture of influenza activity.