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Results for “Supine Position”

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At least 613 records · Page 34Linked to original sources

PubMed2006

Changes in aortic blood flow induced by passive leg raising predict fluid responsiveness in critically ill patients.

INTRODUCTION: Esophageal Doppler provides a continuous and non-invasive estimate of descending aortic blood flow (ABF) and corrected left ventricular ejection time (LVETc). Considering passive leg raising (PLR) as a reversible volume expansion (VE), we compared the relative abilities of PLR-induced ABF variations, LVETc and respiratory pulsed pressure variations (DeltaPP) to predict fluid responsiveness. METHODS: We studied 22 critically ill patients in acute circulatory failure in the supine position, during PLR, back to the supine position and after two consecutive VEs of 250 ml of saline. Responders were defined by an increase in ABF induced by 500 ml VE of more than 15%. RESULTS: Ten patients were responders and 12 were non-responders. In responders, the increase in ABF induced by PLR was similar to that induced by a 250 ml VE (16% versus 20%; p = 0.15). A PLR-induced increase in ABF of more than 8% predicted fluid responsiveness with a sensitivity of 90% and a specificity of 83%. Corresponding positive and negative predictive values (PPV and NPV, respectively) were 82% and 91%, respectively. A DeltaPP threshold value of 12% predicted fluid responsiveness with a sensitivity of 70% and a specificity of 92%. Corresponding PPV and NPV were 87% and 78%, respectively. A LVETc of 245 ms or less predicted fluid responsiveness with a sensitivity of 70%, and a specificity of 67%. Corresponding PPV and NPV were 60% and 66%, respectively. CONCLUSION: The PLR-induced increase in ABF and a DeltaPP of more than 12% offer similar predictive values in predicting fluid responsiveness. An isolated basal LVETc value is not a reliable criterion for predicting response to fluid loading.

Aged↗

PubMed2004

Left lateral vs. supine, wedged position for development of block after combined spinal-epidural anaesthesia for Caesarean section.

This prospective, randomised controlled trial compared a spinal block developing in the left lateral position (LL), after sitting a combined spinal-epidural for Caesarean section with the woman sitting -- using intrathecal hyperbaric bupivacaine and fentanyl -- with a block developing in the supine, wedged position (SW). The median (IQR) block onset times for loss of cold sensation to T4 bilaterally for LL and SW women were 15 (13-19) and 12 (10.8-14) min, respectively (p = 0.004). Unilateral blocks did not occur in the left lateral group. There were no other significant differences between groups, except the median [range] 1-min Apgar scores, which were 9 [8-10] and 9 [6-9] in the LL and SW groups, respectively (p = 0.04). In summary, the LL position is associated with a relatively slower block onset, but produces a spinal block with similar characteristics to that obtained in the SW position.

Adult↗

PubMed2001

[Quantitative evaluation of esophageal scintigraphy in systemic sclerosis].

BACKGROUND: Esophageal involvement by systemic sclerosis (SSc) is frequent. The purpose of this study was to evaluate esophageal motility disorders quantitatively. METHODS: We investigate esophageal scintigraphy in 22 patients with SSc. Esophageal scintigraphy was obtained with swallowing physiological saline in supine position, and swallowing soup in supine and sitting positions. Data was acquired with 0.5 sec per frame for 192 frames in the anterior view. We employed a condensed image as a visual evaluation, half-life and retention rate as a quantitative evaluation, which were obtained from time-activity curves generated from regions of interest on the whole esophagus. The half-life and retention rate were compared with classification of Barnett, stages of SSc, and modified Rodnan total skin score (TSS). RESULTS: No significant differences were seen in classification of Barnett and the stages of SSc. No significant difference was seen between swallowing water and soup in the supine position. The retention rate was significantly prolonged in the supine position than in the sitting position. The retention rate of soup study in the sitting position correlated with TSS (r = 0.61). CONCLUSION: Esophageal scintigraphy in the sitting position is useful in evaluation of esophageal motility in SSc.

Adult↗

PubMed1979

[Orthostatic hypotension in complicated diabetes mellitus: study of the renin-angiotensin-aldosterone system (author's transl)].

Plasma renin activity (P.R.A.) and plasma aldosterone (P.A.) were studied basally and after various stimuli in eight diabetic subjects with orthostatic hypotension and autonomic neuropathy. Five of them had chronic renal failure and proteinuria. On a diet containing 100 mEq Na/24 H, mean P.R.A. was 0,80 +/- 0,32 ng/ml/h in the supine position and 0,95 +/- 0,43 ng/ml/h in the upright position (N.S.); mean P.A. was 111 +/- 77 pg/ml in the supine position and 234 pg/ml in the upright position (p less than 0,01). On a diet containing 10 mEq Na/24 H, mean P.R.A. was 1,54 +/- 0,76 ng/ml/h in the supine position and 2,44 +/- 1,53 ng/ml/h in the upright position (N.S.). There was little stimulation of P. R. A. by low sodium intakes. After furosemide (n = 6), epinephrine + norepinephrine (n = 4) or diazoxide (n = 2), there was no stimulation of P.R.A. and P.A. Thus in diabetic patients with orthostatic hypotension and autonomic neuropathy basal values of P.R.A. and P.A. are in the normal range but there is dysregulation of renin-angiotensin-aldosterone system.

Adult↗

PubMed1998

Supine empty stress test as a predictor of low valsalva leak point pressure.

Our objective was to determine whether a positive supine empty stress test is predictive of a low Valsalva leak point pressure (< or =60 cm of water). Evaluation was carried out on 179 patients with a history of genuine stress incontinence confirmed with urodynamic testing. All patients had a supine stress test performed after voiding. Residual urine determinations were all <100 cc. A vesical Valsalva leak point pressure determination (cough and strain) was performed during multichannel urodynamics with 150 cc in the bladder. Urethral profilometry was performed at maximum capacity. There was a statistically significant relationship between a low leak point pressure and a positive supine empty stress test (P < 0.000). The supine empty stress test had a sensitivity of 79% and a specificity of 62.5% for the detection of a low leak point pressure. The negative predictive value was high at 90%. For the age group 50 years and younger the negative predictive value was 95%. However, there was no significant relationship between a positive supine empty stress test and a low maximal urethral closure pressure. We conclude that the supine empty stress test is a useful screening test for a low leak point pressure but not a low urethral closure pressure. Its high negative predictive value is useful in excluding the presence of a low leak point pressure and may help the clinician to determine which patients with genuine stress incontinence need further assessment of the dynamic function of the urethral sphincter.

Exercise Test↗

PubMed1990

Regional deposition of aerosolized pentamidine. Effects of body position and breathing pattern.

OBJECTIVE: To evaluate the effects of varying body position and breathing pattern on overall lung distribution of aerosolized pentamidine. DESIGN: Nonrandomized control trial with four weekly inhalational treatments. SETTING: The nuclear medicine department of a voluntary hospital. PATIENTS: Sixteen men with the acquired immunodeficiency syndrome (AIDS) or positive serology for the human immunodeficiency virus (HIV). Thirteen patients (81%) completed the study. INTERVENTIONS: Patients inhaled a solution of either saline and technetium-99m bound to diethylenetriamine penta-acetic acid or sterile water, pentamidine (60 mg), and technetium-99m bound to human serum albumin. On weekly visits, the patients inhaled the aerosol solution using four methods: sitting, supine, sitting with an abdominal binder, and sitting and breathing from residual volume with a shallow inspiration. MEASUREMENTS AND MAIN RESULTS: Deposition scans, obtained after each aerosol inhalation, were superimposed on each patient's equilibrium xenon scan, and a frequency distribution histogram was constructed. An asymmetry index was determined from this histogram. The lower the asymmetry index, the more homogeneous the aerosol distribution. Only use of the supine position showed a significant decrease in the asymmetry index (mean, 0.34 +/- 0.02 in the supine position, 0.48 +/- 0.03 in the sitting position; P less than 0.001). CONCLUSIONS: Aerosol distribution in the lungs was more uniform when administered to patients in the supine position. Patients receiving aerosolized pentamidine may benefit from inhalation in the supine position; these results should be verified by clinical study.

Adult↗

PubMed2005

[Otolith function tests--a differentiated, quality-assured screening system].

INTRODUCTION: More than 30% of all otogenic vestibular disorders are related to isolated macular dysfunction. Videooculographic examination techniques for the otolith-ocular reflex, e. g. by means of eccentric rotation tests, are not widely used in clinical routine as these put a considerable strain on technical and staff resources. Thus, there is a considerable risk of "false negative" classification of vertigo disorders being labelled as "non-otogenic". By means of vestibular-evoked myogenic potentials (VEMPs) and caloric irrigation in prone and supine position, several examination techniques for a side-related investigation of macula-induced vestibulo-ocular reflexes are available. The objective of this study is to compare and evaluate these techniques as screening tests. METHODS: In 32 patients with vestibular disorders we performed investigations for VEMPs, eccentric rotation tests, as well as caloric irrigation for macular reaction in prone and supine position. In addition, we performed other audiologic and vestibular function tests which were complemented by the clinical course in order to differentiate each case between otogenic and non-otogenic vertigo with or without macular affection. RESULTS: The technical feasibility as well as patients' acceptance for VEMP testing is better than for eccentric rotation tests. The sensitivity index for VEMPs (89%) as well as for caloric irrigation in prone and supine position for macular examination (71%) is satisfactory. However, the specificity of VEMPs is inferior (53%) to eccentric rotation (100%). DISCUSSION: Both the examination for VEMPs as well as caloric macular testing in prone and supine position carry features which make them feasible for screening, even though these two procedures test for two different parts of the otolith system. However, to confirm a diagnosis and to set up a therapeutic concept for macular function disorders, eccentric rotation should be added.

Caloric Tests↗

PubMed1998

Nasal resistance in snorers with or without sleep apnea: effect of posture and nasal ventilation with continuous positive airway pressure.

We investigated the effects of posture and nasal ventilation with continuous airway pressure (CPAP) on nasal resistance in snorers with or without obstructive sleep apnea (OSA). Posterior rhinomanometry was performed in 70 snorers referred for polysomnography and in 11 nonsnoring volunteers, (1) in the seated posture; (2) and (3) after 10 minutes in the supine position, before and after inhalation of oxymetazoline; and (4) 10 minutes after return to the seated position. The effect of CPAP on posterior rhinomanometry was also examined in the nonsnorers and in 12 of the snorers. Changing from the seated to the supine position resulted in an increase in resistance in snorers and nonsnorers (resistance supine 182 +/- 10.9% and 128 +/- 6.7% respectively of seated value, p < 0.05). After oxymetazoline instillation, resistance in the supine position decreased but remained higher in snorers than baseline value in the seated position. Effects of posture and oxymetazoline were similar in snorers with or without sleep apnea. During nasal ventilation with CPAP, resistance was 30 +/- 3.8 and 45 +/- 4.4% of value before CPAP in snorers and nonsnorers, respectively (p < 0.05). These effects of posture and CPAP were also observed when resistance was measured with anterior rhinomanometry. In conclusion, nasal resistance measured with posterior rhinomanometry in the supine position is not predictive for OSA. Nasal ventilation with CPAP resulted in an acute and marked decrease in nasal resistance.

Adult↗

PubMed2001

Sympathetic nervous system overactivity in hypertensive patients with chronic renal failure--role of upright body position.

OBJECTIVE: The renal functional consequences of an activated sympathetic nervous system and plasma atrial natriuretic hormone (ANP) in various renal diseases are not well described. We hypothesize that norepinephrine (NE) and ANP have antagonizing effects on renal hemodynamics in diseased kidneys. MATERIAL AND METHODS: Plasma NE, ANP. glomerular filtration rate (GFR), effective renal plasma flow (ERPF) and mean arterial pressure (MAP) were measured in the upright position in healthy controls (n = 9) and hypertensive patients with reduced GFR (n =11). The same parameters were compared between healthy controls (n = 6) and hypertensive patients with reduced GFR (n = 6) in upright and supine positions. RESULTS: Upright plasma NE and ANP were significantly elevated in the patients compared with the controls (4.4 +/- 0.4 vs 2.1 +/- 0.2 nmol/l (p < 0.001) and 1.3.5 +/- 2.1 vs 6.9 +/- 1.0 nmol/l (p < 0.01) respectively). With change from upright to supine position plasma NE decreased in the controls (2.2 +/- 0.3 vs 1.7 +/- 0.3 nmol/l) (p < 0.01) and patients (3.8 +/- 0.4 vs 2.6 +/- 0.4) (p < 0.01). Supine ANP increased in controls (5.5 +/- 1.0 vs 8.3 +/- 1.1) (p < 0.01) but not in patients (14.3 +/- 3.8 vs 16.1 +/- 3.8 nmol/l) (p > 0.10). Plasma NE correlated positively with MAP (p < 0.001) and negatively with GFR (p < 0.01) in the upright but not supine position. A positive correlation between NE and ANP was observed in upright (p < 0.001) but not in supine position. ANP correlated negatively with GFR in the upright (p < 0.01) but not supine position. No position dependent changes were seen in GFR and ERPF, but supine filtration fraction (FF) increased insignificantly in the patient group (0.23 +/- 0.02 vs 0.24 +/- 0.02) (p < 0.05). CONCLUSION: Hypertensive patients with reduced GFR have elevated levels of plasma NE and ANP in the upright body position. When the upright and supine positions are compared, plasma NE declines in the supine position in controls and hypertensive renal failure patients. and plasma ANP levels are elevated only in the upright position in hypertensive renal failure patients where the sympathetic nervous system is activated. A significant positive relationship between plasma NE and ANP was observed only in the upright position. The upright body position seems superior to recumbency in the characterization of these hormonal changes in hypertensive chronic renal failure patients.

Atrial Natriuretic Factor↗

PubMed2001

Operative management for sacrococcygeal teratoma diagnosed in utero.

BACKGROUND/PURPOSE: Sacrococcygeal teratomas (SCT) diagnosed in utero have been reported to be large and associated with high perinatal mortality rate. However, operative management including timing of operation after birth, combined abdominal approach for devascularization, and the position of the patients during resection is not well established. METHODS: A retrospective review of 14 patients with SCT between 1978 and 1999 was performed. To prevent massive bleeding during surgery, the authors used an abdominoperineal resection in the supine position after devascularization. The patients' clinical and sonographic characteristics, prenatal outcome, operative management, and postnatal outcomes were examined. RESULTS: One fetus died in utero. Two patients died within a week, but no late death and no malignant degeneration were noted. A staged operation with devascularization was performed in 2 patients, and 1 death occurred. Surgical management was analyzed between survivors without massive bleeding at surgery (n = 9) and others (n = 4). A significant difference was observed in the subgroup of tumor resection with devascularization or supine position and that of early resection with devascularization or supine position. CONCLUSIONS: Early resection using the abdominoperineal approach supported by close antenatal sonography may be preferable for a favorable outcome. Resection in the supine position after devascularization may have advantages of respiratory management, cardiac resuscitation, and bleeding prevention. J Pediatr Surg 36:545-548.

Female↗

PubMed1980

The effects of posture on capillary blood flow pulse and gas exchange in the lungs of man.

Cardiac output and pulmonary capillary blood flow were measured on 5 normal subjects to dye dilution and N2O-body plethysmograph method, respectively. To facilitate calculations and to improve signal to noise ratio, a computer of average transient was used. Cardiac output increased from 7.16 +/- SEM 0.86 L/min to 8.46 +/- 0.72 L/min after the subject changed his posture from upright to supine. Pulmonary capillary blood flow also increased from 5.2 +4- 0.44 L/min to 6.95 +/- 0.48 L/min. These changes were mostly due to changes in stroke volume. The differences between cardiac output and pulmonary capillary blood flow were 19% and 15% in upright and supine positions, respectively. Conduction time of blood flow pulse from pulmonic valve to pulmonary capillary beds prolonged significantly in supine position. Flow acceleration and pulsatility index did not change by posture. Changes in flow acceleration and changes in PaO2 were significantly correlated. These results indicate: 1) profiles of pulmonary capillary blood flow pulse do not alter by posture except conduction time, 2) zone I which is normally closed because of gravity in upright position seems to recruit in supine position, and 3) blood flow acceleration is responsible at least partially for postural changes in PaO2.

Adult↗

PubMed2005

Axial load-dependent cervical spinal alterations during simulated upright posture: a comparison of healthy controls and patients with cervical degenerative disease.

OBJECT: The objectives of this study were to simulate the upright loading condition in the cervical spine by applying a new compression device during supine posture and to assess intervertebral angles and cross-sectional areas of the spinal cord and dural tube before and during axial compression. METHODS: A magnetic resonance (MR) imaging-compatible device was developed to create axial compression with the patient in the supine position. Lateral radiographs were obtained in upright and supine positions with an axial load of 0% (supine) and by applying a cervical compression device at 7, 10, and 13% of body weight (BW) in 18 control individuals and seven symptomatic patients with cervical degenerative disc disease (DDD). Additionally, cervical MR images acquired in 17 controls and 12 patients were compared before and during an axial load of 8.4% BW in terms of anteroposterior diameter and cross-sectional area of the dural sac. The supine intervertebral angles with loads of 0, 7, 10, and 13% of the individuals' BW relative to upright posture were -8.1+/-1.3, -2.3+/-1.4, 1.3+/-1.9, and 2.8+/-2 degrees, respectively. Subsequent axial force was interpolated as 8.9% of BW to simulate upright cervical spine alignment. Under an axial loading similar to that created by the upright posture, the dural sac narrowed at the C5-6 interspace in asymptomatic individuals and at the C6-7 interspace in patients with cervical DDD. CONCLUSIONS: This cervical compression device may be a useful tool to simulate upright cervical spinal alignment. The results of this study help in understanding the pathophysiology of symptoms related to cervical degenerative disorders in upright posture.

Adult↗

PubMed2002

Physiological relationship between autonomic reactions and arousals in infancy.

OBJECTIVE: Changes in blood pressure (BP) were measured following auditory stimuli in the prone and the supine position to study the correlation between arousal from sleep and autonomic responses. METHOD: Two newborns born at term, two infants and four children were recorded polygraphically during one night, while sleeping in the prone and the supine position. They were exposed to white noises of increasing intensities during both rapid eye movement (REM) and non-rapid eye movement (NREM) sleep in each position. BP changes were measured by Finapress in the children and by pulse transient time (PTT) in the infants and newborns. RESULTS: Basal systolic BP pressures were lower (P<0.001) and PTT were higher (P=0.008) in the prone than in the supine position in children and in infants. Following the auditory stimulations, the increases in systolic BP (P=0.024) and the decreases in PTT (P=0.006) were smaller in prone than in supine position. During cortical arousals, the same findings were found, independently of sleep stages. CONCLUSION: Compared with when they are sleeping supine, children and infants sleeping prone had lower basal BP and higher PTT and smaller changes in BP and PTT after auditory stimulation. Reduced BP changes to stimuli could be implicated in the increased arousal thresholds in prone position.

Journal Article↗

PubMed2002

Prone-position ventilation induces sustained improvement in oxygenation in patients with acute respiratory distress syndrome who have a large shunt.

OBJECTIVES: Prone-position ventilation (PPV) induces acute improvement in oxygenation in many patients with acute respiratory distress syndrome (ARDS), with some maintaining their oxygenation even after they were returned to the supine position, but it is unclear what clinical factors determine the sustained oxygenation benefit. We hypothesized that patients with ARDS who have a larger shunt would have a better acute and sustained oxygenation response to PPV. DESIGN: Prospective, nonrandomized interventional study. SETTING: Medical and surgical intensive care units, university tertiary care center. PATIENTS: Twenty-two consecutive patients, with ARDS with an average PaO2/FiO2 of 94, were administered PPV for 12 hrs followed by supine-position ventilation for 2 hrs. MEASUREMENTS: Hemodynamic and gas exchange variables were monitored. The shunt was measured as venous admixture at an FiO2 of 1.0, and compliances of the respiratory system, lung, and chest wall were measured by the esophageal balloon technique before PPV, during PPV, and during subsequent supine-position ventilation. MAIN RESULTS: Fourteen patients (64%) responded to PPV, with PaO2/FiO2 increasing by > or =20. These changes were associated with a decrease in chest wall compliance. Responders had significantly shorter time from ARDS to PPV, a lower baseline PaO2/FiO2, and a higher venous admixture. All responders maintained the improvement in oxygenation and had a greater respiratory system compliance after returning to the supine position. Time from ARDS to PPV and baseline lung injury score were negatively associated, whereas chest wall compliance, heart rate, and PaCO2 were positively associated with sustained improvement in oxygenation. CONCLUSIONS: PPV induced acute and sustained improvement in oxygenation in many patients with ARDS. The sustained improvement is more significant if PPV is administered early to patients with a larger shunt and a more compliant chest wall. Measuring venous admixture and chest wall compliance before PPV may help select a subgroup of patients with ARDS who may benefit the most from PPV.

Adult↗

PubMed2000

Positional MR imaging of the lumbar spine: does it demonstrate nerve root compromise not visible at conventional MR imaging?

PURPOSE: To evaluate whether positional magnetic resonance (MR) images of the lumbar spine demonstrate nerve root compromise not visible on MR images obtained with the patient in a supine position (conventional MR images). MATERIALS AND METHODS: Thirty patients with chronic low back pain unresponsive to nonsurgical treatment and with disk abnormalities but without compression of neural structures were included. Positional MR images were obtained by using an open-configuration, 0.5-T MR imager with the patients seated and with flexion and extension of their backs. The disk and nerve root were related to the body position. Nerve root compression and foraminal size were correlated with the patient's symptoms, as assessed with a visual analogue scale. RESULTS: Nerve root contact without deviation was present in 34 of 152 instances in the supine position, in 62 instances in the seated flexion position, and in 45 instances in the seated extension position. As compared with the supine position, in the seated flexion position nerve root deviation decreased from 10 to eight instances; in the seated extension position, it increased from 10 to 13 instances. Nerve root compression was seen in one patient in the seated extension position. Positional pain score differences were significantly related to changes in foraminal size (P =.046) but not to differences in nerve root compromise. CONCLUSION: Positional MR imaging more frequently demonstrates minor neural compromise than does conventional MR imaging. Positional pain differences are related to position-dependent changes in foraminal size.

Adult↗

PubMed1996

Effect of jaw position and posture on forced inspiratory airflow in normal subjects and patients with obstructive sleep apnea.

OBJECTIVE: This study evaluated whether substantial airflow changes occur by changing both body posture and jaw position in normal subjects and patients with obstructive sleep apnea (OSA). DESIGN: A case-control design was utilized to assess group differences (OSA vs control) and each subject served as his/her own control subject to assess condition differences (jaw position and body posture changes). Subjects included 16 male patients with OSA (aged 33 to 71 years) whose conditions were diagnosed at the UCLA Sleep Disorders Laboratory with a polysomnographic recording, and 9 male non-OSA subjects (aged 22 to 52 years). The experimental intervention in the study involved alterations in body posture and jaw positioning. Airflow changes were determined using a spirometer that assessed the velocity of airflow during a forced inspiration. Subjects in this study all had the middle portion (25 to 75%) of their maximum forced inspiratory flow (FIF25-75) curve measured in three positions; (1) normal jaw position-upright body posture (N-U); (2) normal jaw position-supine body posture (N-S); and (3) protrusive jaw position-supine body posture (P-S). SETTING: The study was conducted at the UCLA Dental Clinical Research Center. RESULTS: Both groups had a significant decrease in their FIF25-75 upon reclining, and there were no significant group differences regarding the magnitude of this change. Both groups also had a nearly full recovery of their FIF25-75 airflow when their jaws were positioned forward while reclining. CONCLUSIONS: These data document that when a patient is in a supine position, a 100% protrusive jaw position allows significantly more inspiratory airflow to occur.

Adult↗

PubMed2004

Successful removal of a knotted fascia iliaca catheter: principles of patient positioning for peripheral nerve catheter extraction.

Peripheral nerve catheters are typically advanced a substantial distance into a perineural sheath, theoretically increasing the risk of catheter knotting and kinking. In this case report, we describe successful removal of a knotted fascia iliaca catheter and discuss principles of nonsurgical catheter extraction. A 64-yr-old woman with bilateral coxarthrosis presented for total hip arthroplasty under combined general/regional anesthesia. A 20-gauge fascia iliaca catheter was inserted before surgery by using a loss-of-resistance "double pop" technique. The catheter was uneventfully advanced 10 cm past the needle tip. After injection of 30 mL of 0.5% bupivacaine with 1:200,000 epinephrine and 100 microg of clonidine, general anesthesia was induced. An infusion of 0.1% bupivacaine at 20 mL/h was initiated in the recovery room for postoperative analgesia. Approximately 48 h later, resistance was encountered during catheter removal. Catheter extraction was attempted by altering patient positioning, including the supine position during which the catheter placement had occurred. Successful catheter removal was achieved by decreasing tension on the fascia lata and fascia iliaca through flexion of the hip joint and by applying firm, steady traction. The catheter was removed intact with a knot approximately 2 cm from the distal tip. We conclude that the principles for removal of entrapped peripheral catheters are not well known and may differ from those for neuraxial catheters. Patient positioning to minimize pressure and tension on the perineural soft tissues may facilitate catheter removal.

Arthroplasty, Replacement, Hip↗

PubMed2004

Changes in intraocular pressure in anesthetized prone patients.

BACKGROUND: Postoperative visual loss occurs more commonly in patients placed prone. The mechanism may be raised intraocular pressure (IOP) causing an ischemic oculopathy. METHODS: IOP was measured in 20 patients undergoing spinal surgery. The IOP was measured prior to intubation, immediately after pronation, and at the end of surgery before the patient was returned to the supine position. Duration of surgery, method of head stabilization and standard physiological parameters were recorded. RESULTS: Both measurements of median IOP in the prone position were significantly higher than that in the supine position (P < 0.001). There was no evidence of a relationship between rise in IOP and duration of surgery, age, or body mass index. There was weak evidence of a tendency for patients whose heads were on pillows to have higher values of IOP at the end of surgery than patients whose heads were supported in pins. CONCLUSION: IOP increases when anesthetized patients are placed in the prone position.

Adolescent↗