ABSTRACT
Study background: Measurement of delivered pharyngeal pressure during continuous positive airway pressure (CPAP) therapy is not in routine practice due to lack of a simple and affordable technique of intrapharyngeal pressure measurement. To overcome the lack of the gold standard solid-state catheter-tip pressure measurement technology in our set up, we improvised a novel method of pressure measurement and tested its validity in a simulated pharynx. Methods: A low-cost pressure transducer was improvised by attaching an orogastric tube to its one end. The other end of the orogastric tube was sealed into an artificial pharynx - a 20 ml syringe. The pressure transducer readings were compared with that obtained by a digital manometer attached to the tip of the syringe. Bland-Altman statistic was used to quantify the measurement reliability of the novel method against the digital manometer. Effect of tube length on the measurement agreement was also studied. The developed technique was applied in new-borns. Results & conclusion: Pressures measured by this technique were in good agreement with that obtained using a digital manometer. This technique has the potential to be used as an alternative to catheter-tip pressure transducers for bedside pharyngeal pressure measurement in new-born babies, especially in underresourced setups.
ABSTRACT
Background & objectives: Chronic obstructive pulmonary disease (COPD) is characterized by slowly progressive airflow limitaion, chronic lung inflammation and associated systemic manifestations. The objective of this preliminary study was to investigate the levels of high sensitivity C reactive protein (hs CRP) and tumour necrosis factor-α (TNF-α) as markers of systemic inflammation and assessment of systemic vascular reactivity that may play an important role in development of cardiovascular disease in COPD patients. Methods: Systemic vascular reactivity was assessed non-invasively by measuring peripheral pulse waveform changes during reactive hyperemia (RH) in 16 COPD patients and 14 controls by photoplethysmography technique (PPG). Parameters measured were pulse wave amplitude (PWA), slope and pulse transit time (PTT). Tumour necrosis factor-α (TNF-α) and hs CRP were measured as markers of inflammation. Results: PWA during the 1st, 2nd and 3rd minutes post release of occlusion were significantly higher than the baseline means in controls, whereas in the patient group there was no significant change in the PWA during any of the observed time periods following release of occlusion, in comparison to the baseline means. Similar results were observed in slope values for patients and controls. Maximum percentage change in PWA during RH with reference to baseline was significantly lower in patients as compared to controls (26.78±20.19 vs 57.20±19.80%, P<0.001). Maximum percentage change in slope during RH with reference to baseline was significantly lower in patients as compared to controls (19.77±10.73 vs 39.25±13.49%, P<0.001). A vascular tone response as represented by PTT was also impaired in the 3rd minute of RH as compared to baseline mean values in COPD patients only. Interpretation & conclusions: Our findings showed raised hs CRP levels and impaired systemic vascular reactivity in COPD patients. Whether these may increase the risk of cardiovascular disease in COPD patients need to be confirmed in future studies with large sample size and appropriate study design.
ABSTRACT
Obesity and insulin resistance (IR) are associated with type 2 diabetes mellitus (DM). Obesity can be quantified by body mass index (BMI) and waist circumference (WC). Similarly, IR is commonly quantified by fasting-plasma-insulin (FPI) and Homeostatic model assessment (HOMA-IR). We aimed our study to find correlation between obesity-parameters and IR especially in the Indian population where despite lower BMI there is more prevalence of type 2 DM. In 34 uncomplicated patients of type 2 DM weight and WC were measured and BMI was calculated. HOMA-IR and FPI level were estimated to assess IR. Significant correlation was found between HOMA-IR and WC (r = +0.368, P = 0.0324) but it was non-significant between HOMAIR and BMI. Correlations were also not significant between FPI and WC or BMI.In conclusion, HOMA-IR and WC are better measures of IR and obesity as compared to FPI and BMI, respectively in type 2 DM.
ABSTRACT
The cardiovascular autonomic neuropathy (CAN) is a known complication of long standing diabetes. In the present study, the prevalence of sympathetic and parasympathetic abnormalities in diabetic patients was evaluated on retrospective analysis of standard tests done for the assessment of CAN. Three different scoring systems were utilized for assessment of CAN namely, Ewing’s crtieria, Bellavere’s criteria and the criteria followed at the Autonomic Function Test laboratory. All the three criteria use different set of tests for classification. A total of 124 patients’ laboratory data was analysed. The abnormality of single test ranged from 6.49% in Valsalva Maneuver to 47.41% in cold pressor test. When Bellavere’s criteria was used only 53 patients had evidence of CAN while Ewing’s criteria revealed that 100 patients had CAN however 69 of these patients could not be categorized. The criteria used by AFT laboratory revealed that isolated sympathetic (49 patients) and paraysmpathetic (10 patients) abnormality can be seen in CAN along with those with combined deficits (42 patients). If the Bellavere’s criteria is used then patients with dominant sympathetic neuropathy are likely to be missed during testing. High prevalence of CAN in tertiary care referral centre suggests that the testing of autonomic functions in diabetics should be done routinely. It is recommended that full battery of test to evaluate both the arms of autonomic drive namely sympathetic and parasympathetic should be done and reported as such.
ABSTRACT
Background & objectives: Patients of orthostatic hypotension may or may not have symptoms of the cerebral hypoperfusion despite fall in the blood pressure. The present study was done to quantify autonomic functions and cerebral autoregulation in patients of orthostatic hypotension with or without symptoms. Methods: The study was conducted in 15 patients of orthostatic hypotension and 15 age, sex matched control subjects. The sympathetic reactivity was measured by diastolic blood pressure response to handgrip test (ΔDBP in HGT) and cold pressor test (ΔDBP in CPT). The parasympathetic reactivity was measured by E:I ratio during deep breathing test (DBT) and Valsalva ratio (VR) during Valsalva maneuver. The cerebral autoregulation was computed from the changes in the cerebral blood flow, cerebrovascular conductance and blood pressure measured during different time points during head-up tilt (HUT). Results: The sympathetic reactivity was lower in patients as compared to controls [ΔDBP in HGT: 10 (4 - 16) vs 18 (12 - 22) mmHg, P<0.01; ΔDBP in CPT : 10 (4-12) vs 16 (10-20) mmHg, P<0.01]. The parasympathetic reactivity was also lower in patients as compared to controls. The sympathetic and parasympathetic reactivity was comparable in the symptomatic and asymptomatic patients. The maximum fall in blood pressure during HUT was comparable between symptomatic and asymptomatic patients (29.14 ± 10.94 vs 29.50 ± 6.39 mmHg), however, the percentage fall in the cerebral blood flow was significantly higher in the symptomatic (P<0.05) compared to asymptomatics. Interpretation & conclusions: Patients with orthostatic hypotension had deficits in sympathetic and parasympathetic control of cardiovascular system. Cerebral autoregulation was present in asymptomatic patients (increase in cerebrovascular conductance) during HUT while it was lost in symptomatic patients.