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Biomedical subjects

A Perel

Publications and source records attributed to A Perel.

At least 109 records · Page 6Linked to original sources

Intermittent mandatory ventilation during anaesthesia using the Manley Servovent ventilator.

The lungs of 25 patients were ventilated with intermittent mandatory ventilation (IMV) during anaesthesia using the Manley Servovent Model MS. This ventilatory mode is especially suitable for prolonged operations in which there is no need for muscle relaxation. While incorporating the advantages of spontaneous and mechanical ventilation, it is superior to both in selected cases. The Manley Servovent Model MS ventilator is capable of delivering IMV without modification, using a single source of gas.

Adolescent↗

The variable effect of PEEP in acute respiratory failure associated with multiple trauma.

Both short and longterm effects of positive end-expiratory pressure (PEEP) on oxygenating capacity (OC) were investigated in three groups of patients with acute respiratory failure following multiple trauma (MT). Group A consisted of six patients with "uncomplicated" MT; Group B, eight patients with MT and generalized sepsis; Group C, nine patients with MT and lung contusion. OC was evaluated in terms of PaO2/FIO2 and P(A-a)DO2 on FIO 2 = 1.0. OC was markedly and equally reduced in the three patient groups before use of PEEP. The use of a mean PEEP of 6-7 cm H2O resulted in an initial improvement in mean PaO2/FIO2 of 152.5, 36.1, and 59.2 mm Hg, and an overall improvement of 196.8, 57.5, and 107.0 mm Hg in Groups A, B, and C, respectively. There was a similar improvement in both the initial and the overall effect of PEEP on P(A-a)DO2 in the three groups. The difference in the improvement in OC due to PEEP was statistically significant between Groups A and B. It is concluded that acute respiratory failure following MT includes a wide spectrum of clinical syndromes, and that the improvement in OCT due to PEEP depends on the clinical sydrome that is responsible for the respiratory failure associated with MT.

Acute Disease↗

A new infusion flow stabilizer.

A new intravenous flow stabilizer (IFS) for keeping constant infusion rates was evaluated and found to be precise and easy to use. The IFS enables precise intravenous treatment while relieving the nursing staff of the frequent checking and readjustment that are required with the intravenous sets in current use.

Humans↗

Cardiopulmonary effects of volume loading in patients in septic shock.

The effect of volume loading in 20 patients with clinical and bacteriological evidence of generalized sepsis was studied. The patients were divided into two groups according to their response to volume loading. Group A included 9 patients in whom the initial pulmonary capillary wedge pressure (PWP)was lower than the central venous pressure (CVP). In this group the intravenous administration of 5089+/-409ml/24 hr fluids was accompanied by a significant rise in blood pressure from 94.4+/-9.3mm Hg to 118.9+/-6.3 MM Hg with no significant change in pulse rate or CVP. PWP rose from 5.7 +/- 1.8 to 10.0 +/- 1.4. The rise in cardiac output from 8.0+/-1.3 liter/min to 9.7+/-1.1 liter/min was not statistically significant. Group B included 11 patients in whom the initial PWP was higher than the CVP. In this group, signs of fluid overloading appeared after administration of 3151+/-540ml/24 hr. There was no significant change in blood pressure, pulse rate, CVP, PWP or cardiac output. Urine output was adequate in both groups. This volume load did not affect pulmonary oxygenating capacity (PaO2/F1O2) and effective lung compliance in both groups, but the maintenance of an unchanged oxygenating capacity necessitated an increase in PEEP in some patients. Thus, synchronous monitoring of PWP and CVP in septic shock is helpful in selecting patients (Group A) who will best respond to fluid loading without deterioration of pulmonary oxygenating capacity. PEEP ventilation may be necessary in some patients to maintain the favorable effect of volume loading.

Adult↗

Anaesthesia in the Guillian-Barré syndrome. A case report and recommendations.

A large proportion of patients with the Guillain Barré syndrome show signs of involvement of the autonomic nervous system beside the better known motor and sensory features of this disease. These patients present a substantial anaesthetic risk because of autonomic dysfunction. We present here an illustrative case in which the administration of a low subarachnoid block resulted in cardiac arrest and offer suggestions for the anaesthetic management of such cases.

Aged↗

Recurrent hallucinations following ketamine.

Recurrent hallucinations appeared in an 11-year-old boy during 5 days following ketamine anaesthesia. Previous anaesthesia with ketamine and adequate diazepam supplementation did not produce any such effect. The phenomenon of delayed recurring hallucinations is a rare but dangerous side-effect of ketamine, not unlike LSD flashbacks. The described case lends support to previous reports on the value of diazepam in the prevention of post-ketamine perceptual abnormalities.

Anesthesia, General↗

The use of systolic pressure variation in hemodynamic monitoring during deliberate hypotension in spine surgery.

The systolic pressure variation (SPV), which is the difference between the maximal and minimal systolic blood pressure (SP) during one ventilatory cycle, was studied in ten patients during posterior spine fusion. To minimize the blood loss, deliberate hypotension to a mean blood pressure of 50 mmHg was introduced by a continuous infusion of sodium nitroprusside. SPV was further divided into two components, delta up and delta down, using SP during a short apnea as a reference point. All hemodynamic parameters were measured at the beginning of anesthesia, 15 minutes after induction of hypotension, before cessation of nitroprusside infusion, and 15 minutes after the end of the hypotensive period. During the hypotensive period (166 +/- 53 minutes), cardiac output (CO) decreased significantly from 4.83 +/- 1.36 L/min to 3.86 +/- 1.07 L/min (p less than 0.05). Heart rate (HR), central venous pressure (CVP), and pulmonary capillary wedge pressure (PCWP) did not change during this period and bore no correlation to the changes in CO. The only variables that changed during the hypotensive period, in addition to CO, were SPV (from 13.1 +/- 4.9 mmHg to 16.9 +/- 5.1 mmHg, p less than 0.02), and delta down (from 6.0 +/- 3.8 mmHg to 9.9 +/- 6.3 mmHg, p less than 0.05). The delta down segment was the only hemodynamic variable whose changes during the hypotensive period showed a significant (p less than 0.018) correlation with the changes in CO. delta down reflects the degree of decrease in left ventricular stroke output in response to a positive pressure breath, and thus is a sensitive indicator of preload.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Echocardiographic left ventricular remodeling and pseudohypertrophy as markers of hypovolemia. An experimental study on bleeding and volume repletion.

BACKGROUND: Monitoring intravascular volume during surgery, especially in major cardiovascular procedures is necessary for appropriate fluid restoration and the maintenance of an adequate cardiac output. In estimating preload, both standard hemodynamic and echocardiographic parameters have been limited. The purpose of this study was to further define the effects of induced hypovolemia on the echocardiographic parameters. In particular, we sought to show whether a decrease in echocardiographic left ventricular area and volume was associated with a significant increase in left ventricular wall thickness (left ventricular pseudohypertrophy) and with changes in LV function. In addition, we sought to investigate the effects of rapid restoration of blood volume on cardiac dimensions and function. METHODS AND RESULTS: Seven anesthetized pigs underwent systemic and right heart pressures and cardiac output measurements. Two-dimensional echocardiographic parasternal long- and short-axis views were obtained during graded bleeding by rapid withdrawal of blood from an arterial cannula, with increments of 5% each up to 30% of calculated blood volume. After completion of the bleeding, the entire amount of the blood withdrawn was retransfused within 4 to 5 minutes. Both hemodynamic and echocardiographic measurements were performed at baseline, immediately after the completion of each stage of bleeding and after blood restoration. Mean (+/- standard deviation) left ventricular wall thickness (mean of septal and posterior wall thickness) was 6.3 +/- 0.1 mm at baseline, 8.3 +/- 1.5 mm at peak bleeding, and 6.2 +/- 0.1 after restoration (p < 0.01). Left ventricular mass did not change during the experiment. Left ventricular end-diastolic volume was 62.8 +/- 20.3 ml at baseline, 37.5 +/- 12.4 ml at peak bleeding (p < 0.0001), and 65.9 +/- 16.7 ml after blood restoration (p < 0.001 compared with 30% bleeding). H/r ratio (posterior wall thickness divided by left ventricular radius) increased from 0.29 +/- 0.07 at baseline to 0.50 +/- 0.19 at peak bleeding returning to 0.26 +/- 0.04 after restoration. Left ventricular ejection fraction was 0.53 +/- 0.10 at baseline and 0.55 +/- 0.20 at peak bleeding (not significant), decreasing to 0.38 +/- 0.11 after blood restoration (p < 0.05 compared with 30% bleeding). End-diastolic volume correlated closely with right atrial pressure (r = -0.82), capillary wedge pressure (r = -0.78), and stroke volume (r = 0.74). Left ventricular ejection fraction inversely correlated with left ventricular end-diastolic volume (r = -0.48) and with end-systolic wall stress (r = -0.62). The changes in interventricular septal and posterior wall thickness were inversely related to left ventricular end-diastolic volume (r = -0.72 and -0.35, respectively). CONCLUSIONS: This study shows that transient concentric left ventricular remodeling (pseudohypertrophy), a phenomenon previously described in cardiac tamponade and during rapid atrial pacing is commonly seen during hypovolemia. This new sign may further enhance the echocardiographic estimation of left ventricular preload.

Animals↗

Continuous psoas compartment block for anesthesia and perioperative analgesia in patients with hip fractures.

BACKGROUND AND OBJECTIVES: The perioperative use of continuous psoas compartment block (CPCB) was compared with traditional pain management for patients with fracture of the femur. The anatomy of CPCB was also tested in cadavers. METHODS: Forty consecutive patients (range, 67-96 years old) were prospectively randomized either to group A (given local anesthetics using a CPCB) or group B (given perioperative analgesia with meperidine). In another part of the study, CPCB was performed in 15 fresh cadavers, and dissection of the lumbar region was performed after dye injection. RESULTS: Continuous psoas compartment block was performed successfully in all patients in group A and was used in the pre- (16-48 hours) and postoperative (72 hours) periods. Visual analog scale score in group A was lower than in group B in 5/7 preoperative and 9/9 postoperative 8 hourly assessments. Differences reached statistical significance (P < .05) in 3 and 5 of the assessments, respectively. Patient satisfaction was higher in group A in the pre- (P < .05) and postoperative periods (P<.03). The block failed to achieve surgical anesthesia in 85% (17/20) of the patients, and additional anesthesia was needed. The anatomic study failed to support the existence of a defined "psoas compartment" previously described, and supported the clinical findings. Injected dye was found in the region of the origin of the sciatic nerve (essential for the production of anesthesia for hip surgery) in only 26% (4/15) of cadavers. CONCLUSIONS: The CPCB seems to be an appropriate technique for efficient and safe perioperative pain control. However, in our dissections, the psoas compartment was not well defined in all patients, thus, using this route for anesthesia may result in only partial success.

Aged↗

The effect of PEEP on oxygenating capacity in acute respiratory failure with sepsis.

We report an evaluation of the effect of postive-end-expiratory-pressure (PEEP) on improving pulmonary oxygenating capacity in the adult respiratory distress syndrome (ARDS), when the latter is associated with generalized gram-negative sepsis. Fifty-seven cases treated in our RICU with PEEP ventilation (April 1972 to January 1975) were retrospectively reviewed. Oxygenating capacity improvement was evaluated in terms of the changes in PaO2/FIO2 and AaDO2 (FIO2 = 1.0). Both the short term (2-3 hours from the initiation of PEEP) and the overall effects of PEEP were evaluated. A mean PEEP of 5.6 cm H2O initially increased PaO2/FIO2 by a mean of 94 torr and decreased AaDO2 (FIO2 = 1.0) by 105 torr in the 28 nonseptic patients. In the 29 septic patients, 5.1 cm H2O PEEP initially increased PaO2/FIO2 by 32 torr and decreased AsDO2 (FIO2 = 1.0) by 38 torr. The differences between the septic and nonseptic patients were statistically significant (P less than 0.001). Likewise, the long-term effect of similar levels of PEEP was in increasing PaO2/FIO2 by 142 torr and by 75 torr in the nonseptic and septic patients, respectively. The final reduction in AaDO2 (FIO2 = 1.0) was 163 torr and 87 torr in the nonseptic and septic patients, respectively. These differences between patient groups were also statistically significant (P less than 0.02). Mortality during PEEP was 15/29 and 3/28 in the septic and nonseptic patients, respectively. Overall mortality in the septic and nonseptic groups was 18/29 and 5/28, respectively. We conclude that ARDS with sepsis constitutes a more severe pulmonary insult than ARDS without sepsis, and/or that generalized sepsis creates a more prolonged pulmonary insult that makes it less amenable to PEEP. Thus, high levels of PEEP may be needed to treat ARDS associated with sepsis.

Adolescent↗

Serum cholinesterase in tetanus.

This paper describes the correlation between serum cholinesterase levels and the severity and course of tetanus in a young patient. The diagnostic and prognostic value and significance of this enzyme as well as the therapeutic value of cholinesterase-restoring agents in tetanus are discussed.

Child↗

Intraperitoneal bupivacaine does not attenuate pain following laparoscopic cholecystectomy.

BACKGROUND: Laparoscopic cholecystectomy is characterized by a short hospital stay. Hence, pain control on the day of surgery is increasingly important. The aim of this study was to evaluate the effect of intraperitoneal bupivacaine on pain relief following laparoscopic cholecystectomy. METHODS: Sixty patients undergoing elective laparoscopic cholecystectomy were prospectively randomized into 2 groups. Following removal of the gallbladder, group A received 100 mg of bupivacaine in 50 cc of saline, installed into the gallbladder bed and right subphrenic space. Group B received saline without bupivacaine. Pain was assessed using a visual/analog scale at fixed-time intervals. RESULTS: No significant difference occurred in the average pain levels between the groups at 1, 2, 4, and 14 hours postsurgery. The average analgesic requirement was lower in the bupivacaine group, but this did not reach statistical significance. CONCLUSION: Application of intraperitoneal bupivacaine did not attenuate pain following laparoscopic cholecystectomy, and no role exists for its routine use.

Adult↗